Method of determining and predicting a ball loss in a ball and ramp assembly

A method of detecting a ball loss condition in a ball and ramp assembly. The method includes providing a drive unit having one or more clutch pack assemblies, one or more motors with a motor output shaft and one or more ball and ramp assemblies. One or more actuation profiles are ran by the motors and an amount of motor current used and a position of the output shaft of the motor is measured during the running of actuation profiles. One or more motor current vs. motor output shaft position plots are generated having one or more characteristic curves based on the amount of current measured and the position of the output shaft measured. The amount of motor current is compared to the motor current of characteristic curve at a given output shaft position and based on that comparison a ball loss condition is identified.

FIELD OF THE DISCLOSURE

The present disclosure relates to a method of determining a ball loss within ball and ramp assembly and predicting when a ball loss will occur within the ball and ramp assembly.

BACKGROUND OF THE DISCLOSURE

Conventional ball and ramp assemblies are used in a drive unit of a vehicle in order to translate the rotational power generated by a motor into an amount of axial movement which allows the ball and ramp assembly to apply an amount of force onto a clutch pack assembly of the drive unit. The ball and ramp assemblies typically include a first plate having a plurality of first plate grooves, a second plate having a plurality of second plate grooves and a plurality of rolling elements interposed between the first and second plates of the ball and ramp assembly. The plurality of rolling elements interposed are also disposed within the plurality of first and second plate grooves in the first and second plates of the ball and ramp assembly. As the plurality of rolling elements make multiple crossings across the plurality of first and second plate grooves of the first and second plate of the ball and ramp assembly, the rotational movement and acceleration of the plurality of rolling elements tend to lose their desired position and fall back toward their home position. When the plurality of rolling elements lose their desired position and fall back toward their home position, the amount of force applied by the ball and ramp assembly onto the clutch pack assembly is reduced or eliminated. This results a loss in the overall functionality of the ball and ramp assembly and the clutch pack assembly which reduces or eliminates the ability of the clutch pack assembly to provide the desired amount of torque vectoring capability to the drive-line of the vehicle. Because there is no feedback through motor position along to determine whether or not a ball loss has occurred, one or more elaborate detection methods need to be performed in order to determine if a ball loss has occurred. These elaborate detection methods increase the overall costs associated with the drive unit assembly, require more time to perform and tend to provide an undesirable amount of false positives.

It would therefore be advantageous to develop a method of detecting a ball loss within a ball and ramp assembly that is quick, accurate and more cost efficient. Additionally, it would therefore be advantageous to develop a method of predicting when a ball loss will likely occur within a ball and ramp assembly in order to prevent a ball loss from occurring thereby improving the overall operation of a drive unit assembly.

SUMMARY OF THE DISCLOSURE

A method of detecting a ball loss condition in a ball and ramp assembly. The method of detecting the occurrence of a ball loss condition includes providing a drive unit having one or more clutch pack assemblies, one or more ball and ramp assemblies and one or more motors with a motor output shaft that is drivingly connected to at least a portion of the one or more ball and ramp assemblies. During the method of detecting the ball loss condition, one or more actuation profiles are ran by the motors and an amount of motor current used and a position of the output shaft of the motor is measured during the running of actuation profiles. One or more motor current vs. motor output shaft position plots are then generated having one or more characteristic curves based on the amount of motor current measured and the position of the motor output shaft measured during the running of the one or more actuation profiles. The amount of motor current measured is then compared to the amount of current in the characteristic curve at a given motor output shaft position and based on that comparison a ball loss condition is identified.

Additionally, the present disclosure includes disclosure relating to a method of predicting when a ball loss condition will occur within one or more ball and ramp assemblies of a drive unit assembly.

DETAILED DESCRIPTION OF THE DISCLOSURE

It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also understood that the specific devices and processes illustrated in the attached drawings, and described in the specification are simply exemplary embodiments of the inventive concepts disclosed and defined herein. Hence, specific dimensions, directions or other physical characteristics relating to the various embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise.

The present disclosure relates to a method for determining if a ball loss has occurred within one or more ball and ramp assemblies of a drive unit. Additionally, the present disclosure relates to a method of predicting when a ball loss will occur within the one or more ball and ramp assemblies of the drive unit. As a non-limiting example, the methods described herein may be used in combination with a drive unit, such as but not limited to, a front drive unit, a rear drive unit, a forward tandem axle drive unit, a rear tandem axle drive unit, a differential assembly and/or any other vehicle drive unit having one or more clutching or clutch pack assemblies with one or more ball and ramp assemblies.

It is within the scope of this disclosure, and as a non-limiting example, that the method of detecting and predicting ball loss in one or more ball and ramp assemblies of a drive unit described herein may be used in automotive, off-road vehicle, all-terrain vehicle, construction, structural, marine, aerospace, locomotive, military, machinery, robotic and/or consumer product applications. Additionally, as a non-limiting example, the method of detecting and predicting ball loss in one or more ball and ramp assemblies of a drive unit described herein may also be used in passenger vehicle, electric vehicle, hybrid vehicle, commercial vehicle, autonomous vehicles, semi-autonomous vehicles and/or heavy vehicle applications.

FIG. 1is a schematic top-plan view of a vehicle2having one or more drive units with one or more ball and ramp assemblies utilizing a method of determining if a ball loss has occurred and/or when a ball loss will occur according to an embodiment of the disclosure. As illustrated inFIG. 1of the disclosure and as a non-limiting example, the2has an engine4which is drivingly connected to a transmission6. As non-limiting example, the engine4of the vehicle2may be an internal combustion engine, an electric motor, a steam turbine and/or a gas turbine. A transmission output shaft8is then drivingly connected to an end of the transmission6opposite the engine4. The transmission6is a power management system which provides controlled application of the rotational power generated by the engine4by means of a gear box.

Drivingly connected to an end of the transmission output shaft8, opposite the transmission6, is a transfer case input shaft10. An end of the transfer case input shaft10, opposite the transmission output shaft8, is drivingly connected to at least a portion of a transfer case12of the vehicle2. The transfer case12of the vehicle2allows for the selective transfer the rotational power from the transmission6to a front axle system14and a tandem axle system16of the vehicle2by utilizing a series of gears and drive shafts. As illustrated inFIG. 1of the disclosure and as a non-limiting example, the transfer case12includes a first transfer case output shaft18and a second transfer case output shaft20.

A first shaft22extends from the first transfer case output shaft18toward the front axle system14of the vehicle2. The first shaft22transmits the rotational power from the transfer case12to the front axle system14of the vehicle2thereby drivingly connecting the transfer case12to the front axle system14. It is within the scope of this disclosure and as a non-limiting example that the first shaft22may be a drive shaft, a propeller shaft, a Cardan shaft or a double Cardan shaft.

Drivingly connected to an end of the first shaft22, opposite the first transfer cane output shaft18, is a front axle system input shaft24. The front axle system input shaft24drivingly connects the first shaft22to a front axle differential assembly26of the front axle system14of the vehicle2. As illustrated inFIG. 1of the disclosure and as a non-limiting example, at least a portion of an end of the front axle system input shaft24, opposite the first shaft22, is drivingly connected to the front axle differential assembly26. It is within the scope of this disclosure and as a non-limiting example that the front axle system input shaft24may be front differential input shaft, a coupling shaft, stub shaft or a front differential pinion shaft. The front axle differential assembly26is a set of gears that allows the outer drive wheel(s) of the vehicle2to rotate at a faster rate that the inner drive wheel(s). The rotational power is transmitted through the front axle system14as described in more detail below.

The front axle system14further includes a first front axle half shaft28and a second front axle half shaft30. As illustrated inFIG. 1of the disclosure and as a non-limiting example, the first front axle half shaft28extends substantially perpendicular to the front axle system input shaft24of the vehicle2. At least a portion of a first end portion32of the first front axle half shaft28is drivingly connected to a first front axle wheel assembly34and at least a portion of a second end portion36of the first front axle half shaft28is drivingly connected to an end of the front axle differential assembly26. It is within the scope of this disclosure and as a non-limiting example that the second end portion36of the first front axle half shaft28may be drivingly connected to a front differential side gear, a separate stub shaft, a separate coupling shaft, a first front axle differential output shaft, a first front axle have shaft connect and disconnect assembly and/or a shaft that is formed as part of a front differential side gear.

Extending substantially perpendicular to the front axle system input shaft24is the second front axle half shaft30of the vehicle2. At least a portion of a first end portion38of the second front axle half shaft30is drivingly connected to a second front axle wheel assembly40of the vehicle2. As illustrated inFIG. 1of the disclosure and as a non-limiting example, at least a portion of a second end portion42of the second front axle half shaft30is drivingly connected to an end of the front axle differential assembly26opposite the first front axle half shaft28. It is within the scope of this disclosure and as a non-limiting example that the second end portion42of the second front axle half shaft30may be drivingly connected to a front differential side gear, a separate stub shaft, a separate coupling shaft, a second front axle differential output shaft, a second front axle half shaft connect and disconnect assembly and/or a shaft that is formed as part of a front differential side gear.

According to the embodiment of the disclosure illustrated inFIG. 1and as a non-limiting example, the front axle system14of the vehicle2may further include the use of one or more front axle differential clutch pack assemblies44. The one or more front axle differential clutch pack assemblies44are used to precisely control the amount of torque that is transferred by the engine4to the first and/or second front axle wheel assemblies34and/or40of the vehicle2. In order to apply an amount of force onto the one or more front axle differential clutch pack assemblies44, one or more front axle system ball and ramp assemblies45are operably connected to at least a portion of the one or more front axle differential clutch pack assemblies44of the vehicle2. The one or more front axle system ball and ramp assemblies45are operably configured to apply a variable amount of force onto the one or more front axle differential clutch pack assemblies44of the front axle system14of the vehicle2.

In order for the one or more front axle system ball and ramp assemblies45to apply a variable amount of force onto the one or more front axle differential clutch pack assemblies44of the vehicle2, a first motor46is drivingly connected to at least a portion of the one or more front axle system ball and ramp assemblies45. It is within the scope of this disclosure and as a non-limiting example that the first motor46of the one or more front axle differential clutch pack assemblies44may be an electric motor, an actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electro-mechanical actuator, an electro-magnetic actuator and/or any other type or motor that is able to convert an amount of energy into mechanical energy.

The one or more front axle system ball and ramp assemblies45and the first motor46of the one or more front axle differential clutch pack assemblies44of the vehicle2are in communication with a control unit48via one or more first data-links50. The one or more first data-links50allow for communication between one or more front axle system ball and ramp assemblies45, the first motor46and the control unit48of the vehicle2. As a non-limiting example, the one or more first data-links50of the vehicle2may be one or more fiber optic cables and/or one or more electrical cables that put the control unit48in optical and/or electrical communication with the first motor46and the one or more front axle system ball and ramp assemblies45of the one or more front axle differential clutch pack assemblies44.

In accordance with the embodiment of the disclosure illustrated inFIG. 1and as a non-limiting example, the control unit48may be in communication with a vehicle bus52via one or more control unit data-links54. It is within the scope of this disclosure and as a non-limiting example that the vehicle bus52may be a Controller Area network (CAN) Bus or a CAN Bus that conforms to the Society of Automotive Engineers (SAE) J-1939 standards. Additionally, it is within the scope of this disclosure and as a non-limiting example that the one or more control unit data-links54may be one or more fiber optic cables and/or one or more electrical cables that put the control unit48in optical and/or electrical communication with the vehicle bus52of the vehicle2.

An end of the second transfer case output shaft20is drivingly connected to an end of the transfer case12opposite the transfer case input shaft10. Extending from the second transfer case output shaft20toward a forward tandem axle system56of the tandem axle system16of the vehicle2is a second shaft58. It is within the scope of this disclosure and as a non-limiting example that the second shaft58of the vehicle2may be a drive shaft, a propeller shaft, a Cardan shaft or a double Cardan shaft.

Drivingly connected to an end of the second shaft58, opposite the second transfer case output shaft20, is a forward tandem axle system input shaft60. As a non-limiting example, the forward tandem axle input shaft60may be a forward tandem axle differential input shaft, a coupling shaft, stub shaft, a forward tandem axle differential pinion shaft, an inter-axle differential input shaft or an inter-axle differential pinion shaft. Drivingly connected to an end of the forward tandem axle input shaft60, opposite the second shaft58, is an inter-axle differential assembly62of the forward tandem axle system56of the vehicle2. The inter-axle differential assembly62is a device that divides the rotational power generated by the engine4between the axles in the vehicle2. The rotational power is transmitted through the forward tandem axle system56as described in more detail below.

As illustrated inFIG. 1of the disclosure and as a non-limiting example, the inter-axle differential assembly62of the vehicle2is drivingly connected to a forward tandem axle differential assembly64and a forward tandem axle system output shaft66. The forward tandem axle differential assembly64is a set of gears that allows the outer drive wheel(s) of the vehicle2to rotate at a faster rate than the inner drive wheel(s). The forward tandem axle system56of the vehicle2further includes a first forward tandem axle half shaft68and a second forward tandem axle half shaft70. As illustrated inFIG. 1of the disclosure and as a non-limiting example, the first forward tandem axle half shaft68extends substantially perpendicular to the forward tandem axle input shaft60of the vehicle2. At least a portion of a first end portion72of the first forward tandem axle half shaft68is drivingly connected to a first forward tandem axle wheel assembly74and at least a portion of a second end portion76of the first forward tandem axle half shaft68is drivingly connected to an end of the forward tandem axle differential assembly64. It is within the scope of this disclosure and as a non-limiting example that the second end portion76of the first forward tandem axle half shaft68may be drivingly connected to a forward tandem axle differential side gear, a separate stub shaft, a separate coupling shaft, a first forward tandem axle differential output shaft, a first forward tandem axle half shaft connect and disconnect assembly and/or a shaft that is formed as part of a forward tandem axle differential side gear.

According to the embodiment of the disclosure illustrated inFIG. 1and as a non-limiting example, the forward tandem axle system56of the vehicle2may further include the use of a first forward tandem axle differential clutch pack assembly78. The first forward tandem axle differential clutch pack assembly78is used to precisely control the amount of torque that is transferred by the engine4to the first forward tandem axle wheel assembly74of the vehicle2. In order to apply an amount of force onto the first forward tandem axle differential clutch pack assembly78, a first forward tandem axle system ball and ramp assembly79is operably connected to at least a portion of the first forward tandem axle differential clutch pack assembly78of the vehicle2. The first forward tandem axle system ball and ramp assembly79is operably configured to apply a variable amount of force onto the first forward tandem axle differential clutch pack assembly78of the forward tandem axle system56of the vehicle2.

In order for the first forward tandem axle system ball and ramp assembly79to apply a variable amount of force onto the first forward tandem axle differential clutch pack assembly78of the vehicle2, a second motor80is drivingly connected to at least a portion of the first forward tandem axle system ball and ramp assembly79. It is within the scope of this disclosure and as a non-limiting example that the second motor80of the first forward tandem axle differential clutch pack assembly78may be an electric motor, an actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electro-mechanical actuator, an electro-magnetic actuator and/or any other type or motor that is able to convert an amount of energy into mechanical energy.

The first forward tandem axle system ball and ramp assembly79and the second motor80of the first forward tandem axle differential clutch pack assembly78of the vehicle2are in communication with the control unit48via one or more second data-links82. The one or more second data-links82allow for communication between first forward tandem axle system ball and ramp assembly79, the second motor80and the control unit48of the vehicle2. As a non-limiting example, the one or more second data-links82of the vehicle2may be one or more fiber optic cables and/or one or more electrical cables that put the control unit48in optical and/or electrical communication with the second motor80and the first forward tandem axle system ball and ramp assembly79of the first forward tandem axle differential clutch pack assembly78.

Extending substantially perpendicular to the forward tandem axle system input shaft60is the second forward tandem axle half shaft70of the vehicle2. At least a portion of a first end portion84of the second forward tandem axle half shaft70is drivingly connected to a second forward tandem axle wheel assembly86of the vehicle2. As illustrated inFIG. 1of the disclosure and as a non-limiting example, at least a portion of a second end portion88of the second forward tandem axle half shaft70is drivingly connected to an end of the forward tandem axle differential assembly64opposite the first forward tandem axle half shaft68. It is within the scope of this disclosure and as a non-limiting example that the second end portion88of the second forward tandem axle half shaft70may be drivingly connected to a forward tandem differential side gear, a separate stub shaft, a separate coupling shaft, a second forward tandem axle differential output shaft, a second forward tandem axle half shaft connect and disconnect assembly and/or a shaft that is formed as part of a forward tandem differential side gear.

In accordance with the embodiment of the disclosure illustrated inFIG. 1and as a non-limiting example, the forward tandem axle system56of the vehicle2may further include the use of a second forward tandem axle differential clutch pack assembly90. The second forward tandem axle differential clutch pack assembly90is used to precisely control the amount of torque that is transferred by the engine4to the second forward tandem axle wheel assembly86of the vehicle2. In order to apply an amount of force onto the second forward tandem axle differential clutch pack assembly90, a second forward tandem axle system ball and ramp assembly91is operably connected to at least a portion of the second forward tandem axle differential clutch pack assembly90of the vehicle2. The second forward tandem axle system ball and ramp assembly91is operably configured to apply a variable amount of force onto the second forward tandem axle differential clutch pack assembly90of the forward tandem axle system56of the vehicle2.

In order for the second forward tandem axle system ball and ramp assembly91to apply a variable amount of force onto the second forward tandem axle differential clutch pack assembly90of the vehicle2, a third motor92is drivingly connected to at least a portion of the second forward tandem axle system ball and ramp assembly90. It is within the scope of this disclosure and as a non-limiting example that the third motor92of the second forward tandem axle differential clutch pack assembly90may be an electric motor, an actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electro-mechanical actuator, an electro-magnetic actuator and/or any other type or motor that is able to convert an amount of energy into mechanical energy.

The second forward tandem axle system ball and ramp assembly91and the third motor92of the second forward tandem axle differential clutch pack assembly90of the vehicle2are in communication with the control unit48via one or more third data-links94. The one or more third data-links94allow for communication between second forward tandem axle system ball and ramp assembly91, the third motor92and the control unit48of the vehicle2. As a non-limiting example, the one or more third data-links94of the vehicle2may be one or more fiber optic cables and/or one or more electrical cables that put the control unit48in optical and/or electrical communication with the third motor92and the second forward tandem axle system ball and ramp assembly91of the second forward tandem axle differential clutch pack assembly90.

Drivingly connected to an end of the forward tandem axle system output shaft66, opposite the inter-axle differential assembly62, is a third shaft96. The third shaft96extends from the forward tandem axle system output shaft66toward a rear tandem axle system98of the vehicle2. As a result, the third shaft98drivingly connects the inter-axle differential assembly62to the rear tandem axle system98of the vehicle2. It is within the scope of this disclosure and as a non-limiting example that the third shaft98may be a drive shaft, a propeller shaft, a Cardan Shaft or a double Cardan shaft.

At least a portion of an end of the third shaft96, opposite the forward tandem axle system output shaft66, is drivingly connected to an end of a rear tandem axle system input shaft100. It is within the scope of this disclosure and as a non-limiting example that the rear tandem axle system input shaft100may be a rear tandem axle differential input shaft, a coupling shaft, stub shaft or a rear tandem axle differential pinion shaft. Drivingly connected to an end of the rear tandem axle input shaft100, opposite the third shaft96, is a rear tandem axle differential assembly102of the rear tandem axle system98of the vehicle2. The rear tandem axle differential assembly102is a set of gears that allows the outer drive wheel(s) of the vehicle2to rotate at a faster rate than the inner drive wheel(s). The rotational power is transmitted through the rear tandem axle system98as described in more detail below.

As illustrated inFIG. 1of the disclosure and as a non-limiting example, the rear tandem axle system98further includes a first rear tandem axle half shaft104and a second rear tandem axle half shaft106. The first rear tandem axle half shaft104extends substantially perpendicular to the rear tandem axle system input shaft100of the vehicle2. At least a portion of a first end portion108of the first rear tandem axle half shaft104is drivingly connected to a first rear tandem axle wheel assembly110and at least a portion of a second end portion112of the first rear tandem axle half shaft104is drivingly connected to an end of the rear tandem axle differential assembly102. It is within the scope of this disclosure and as a non-limiting example that the second end portion112of the first rear tandem axle half shaft104is drivingly connected to a rear tandem axle differential side gear, a separate stub shaft, a separate coupling shaft, a first rear tandem axle differential output shaft, a first rear tandem axle half shaft connect and disconnect assembly and/or a shaft that is formed as part of a rear tandem axle differential side gear.

According to the embodiment of the disclosure illustrated inFIG. 1and as a non-limiting example, the rear tandem axle system98of the vehicle2may further include the use of a first rear tandem axle differential clutch pack assembly114. The first rear tandem axle differential clutch pack assembly114is used to precisely control the amount of torque that is transferred by the engine4to the first rear tandem axle wheel assembly110of the vehicle2. In order to apply an amount of force onto the first rear tandem axle differential clutch pack assembly114, a first rear tandem axle system ball and ramp assembly115is operably connected to at least a portion of the first rear tandem axle differential clutch pack assembly114of the vehicle2. The first rear tandem axle system ball and ramp assembly115is operably configured to apply a variable amount of force onto the first rear tandem axle differential clutch pack assembly114of the rear tandem axle system98of the vehicle2.

In order for the first rear tandem axle system ball and ramp assembly115to apply a variable amount of force onto the first rear tandem axle differential clutch pack assembly114of the vehicle2, a fourth motor116is drivingly connected to at least a portion of the first rear tandem axle system ball and ramp assembly115. It is within the scope of this disclosure and as a non-limiting example that the fourth motor116of the first rear tandem axle differential clutch pack assembly114may be an electric motor, an actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electro-mechanical actuator, an electro-magnetic actuator and/or any other type or motor that is able to convert an amount of energy into mechanical energy.

The first rear tandem axle system ball and ramp assembly115and the fourth motor116of the first rear tandem axle differential clutch pack assembly114of the vehicle2are in communication with the control unit48via one or more fourth data-links118. The one or more fourth data-links118allow for communication between first rear tandem axle system ball and ramp assembly115, the fourth motor116and the control unit48of the vehicle2. As a non-limiting example, the one or more fourth data-links118of the vehicle2may be one or more fiber optic cables and/or one or more electrical cables that put the control unit48in optical and/or electrical communication with the fourth motor116and the first rear tandem axle system ball and ramp assembly115of the first rear tandem axle differential clutch pack assembly114.

Extending substantially perpendicular to the rear tandem axle system input shaft100is the second rear tandem axle half shaft106of the vehicle2. At least a portion of a first end portion120of the second rear tandem axle half shaft106is drivingly connected to a second rear tandem axle wheel assembly122of the vehicle2. As illustrated inFIG. 1of the disclosure and as a non-limiting example, at least a portion of a second end portion124of the second rear tandem axle half shaft106is drivingly connected to an end of the rear tandem axle differential assembly102opposite the first rear tandem axle half shaft104. It is within the scope of this disclosure and as a non-limiting example that the second end portion124of the second rear tandem axle half shaft106may be drivingly connected to a rear tandem differential side gear, a separate stub shaft, a separate coupling shaft, a second rear tandem axle differential output shaft, a second rear tandem axle half shaft connect and disconnect assembly and/or a shaft that is formed as part of a rear tandem differential side gear.

In accordance with the embodiment of the disclosure illustrated inFIG. 1and as a non-limiting example, the rear tandem axle system98of the vehicle2may further include the use of a second rear tandem axle differential clutch pack assembly126. The second rear tandem axle differential clutch pack assembly126is used to precisely control the amount of torque that is transferred by the engine4to the second rear tandem axle wheel assembly122of the vehicle2. In order to apply an amount of force onto the second rear tandem axle differential clutch pack assembly126, a second rear tandem axle system ball and ramp assembly127is operably connected to at least a portion of the second rear tandem axle differential clutch pack assembly126of the vehicle2. The second rear tandem axle system ball and ramp assembly127is operably configured to apply a variable amount of force onto the second rear tandem axle differential clutch pack assembly126of the rear tandem axle system98of the vehicle2.

In order for the second rear tandem axle system ball and ramp assembly127to apply a variable amount of force onto the second rear tandem axle differential clutch pack assembly126of the vehicle2, a fifth motor128is drivingly connected to at least a portion of the second rear tandem axle system ball and ramp assembly127. It is within the scope of this disclosure and as a non-limiting example that the fifth motor128of the second rear tandem axle differential clutch pack assembly126may be an electric motor, an actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electro-mechanical actuator, an electro-magnetic actuator and/or any other type or motor that is able to convert an amount of energy into mechanical energy.

The second rear tandem axle system ball and ramp assembly127and the fifth motor127of the second rear tandem axle differential clutch pack assembly126of the vehicle2are in communication with the control unit48via one or more fifth data-links130. The one or more fifth data-links130allow for communication between second rear tandem axle system ball and ramp assembly127, the fifth motor128and the control unit48of the vehicle2. As a non-limiting example, the one or more fifth data-links130of the vehicle2may be one or more fiber optic cables and/or one or more electrical cables that put the control unit48in optical and/or electrical communication with the fifth motor128and the second rear tandem axle system ball and ramp assembly127of the second rear tandem axle differential clutch pack assembly126.

While the embodiment of the disclosure illustrated inFIG. 1illustrates the motors46,80,92,116and128and the ball and ramp assemblies45,79,91,115and127as being in electrical and/or optical communication with the control unit148, it is within the scope of this disclosure that one or more of the motors46,80,92,116and128and the ball and ramp assemblies45,79,91,115and127may be in wireless communication with the control unit148. As a non-limiting example the wireless communication between the motors46,80,92,116and/or128, the ball and ramp assemblies45,79,91,115and/or127and the control unit148may be a Bluetooth connection, a Wi-fi connection, a cellular connection and/or a radio wave connection. As a result, it is within the scope of this disclosure that the one or more of the motors46,80,92,116and/or128, the ball and ramp assemblies45,79,91,115and/or127and the control unit148may be operably configured to send and/or receive the data and/or instructions needed for the operation of clutch pack assemblies44,78,90,114and/or126of the vehicle2. Additionally, as a result, it is within the scope of this disclosure and as a non-limiting example that the motors46,80,92,116and/or128, the ball and ramp assemblies45,79,91,115and/or127and the control unit148may be operably configured to send and/or receive the data and/or instructions needed in order to determine if a ball loss has occurred or to predict when a ball loss will occur within one or more of the ball and ramp assemblies45,79,91,115and/or127.

Furthermore, while the embodiment of the disclosure illustrated inFIG. 1illustrates the control unit48being in electrical and/or optical communication with the vehicle bus52of the vehicle1, it is within the scope of this disclosure that the control unit48may be wireless communication with the vehicle bus52. As a non-limiting example the wireless communication between the control unit48and the vehicle bus52may be a Bluetooth connection, a Wi-fi connection, a cellular connection and/or a radio wave connection. As a result, it is within the scope of this disclosure that the control unit48and the vehicle bus52may be operably configured to send and/or receive the data and/or instructions needed for the operation of the clutch pack assemblies26,78,90,114and/or126of the vehicle2. Additionally, as a result, it is within the scope of this disclosure and as a non-limiting example that the control unit48and the vehicle bus52may be operably configured to send and/or receive the data and/or instructions needed in order to determine if a ball loss has occurred or to predict when a ball loss will occur within one or more of the ball and ramp assemblies45,79,91,115and/or127.

It is within the scope of this disclosure and as a non-limiting example that a ball loss within one or more of the ball and ramp assemblies45,79,91,115and/or127may be determined using a ball loss detection method according to an embodiment of the disclosure. Additionally, it is within the scope of this disclosure and as a non-limiting example that one or more of the ball and ramp assemblies45,79,91,115and/or127may utilize a method of predicting a ball loss condition according to an embodiment of the disclosure.

FIG. 2is a schematic top-plan view of another vehicle100having one or more drive units with one or more ball and ramp assemblies utilizing a method of determining if a ball loss has occurred and/or when a ball loss will occur according to an embodiment of the disclosure. The vehicle100illustrated inFIG. 2is the same as the vehicle2illustrated inFIG. 1, except where specifically noted below. As illustrated inFIG. 2of the disclosure and as a non-limiting example, the vehicle100does not include the use of the transfer case12that is drivingly connected to at least a portion of the front axle system differential assembly26having the one or more front axle differential clutch pack assemblies44.

In accordance with the embodiment of the disclosure illustrated inFIG. 2and as a non-limiting example, at least a portion of the end of the transmission output shaft8, opposite the transmission6, is drivingly connected to at least a portion of the end of the second shaft58opposite the forward tandem axle system input shaft60. As a result, in accordance with the embodiment of the disclosure illustrated inFIG. 2and as a non-limiting example, the second shaft58of the vehicle100extends from the transmission output shaft8toward the inter-axle differential assembly62of the forward tandem axle system56of the vehicle100.

It is within the scope of this disclosure and as a non-limiting example that a ball loss within one or more of the ball and ramp assemblies79,91,115and/or127may be determined using a ball loss detection method according to an embodiment of the disclosure. Additionally, it is within the scope of this disclosure and as a non-limiting example that one or more of the ball and ramp assemblies79,91,115and/or127may utilize a method of predicting a ball loss condition according to an embodiment of the disclosure.

FIG. 3is a schematic top-plan view of yet another vehicle200having one or more drive units with one or more ball and ramp assemblies utilizing a method of determining if a ball loss has occurred and/or when a ball loss will occur according to an embodiment of the disclosure. As illustrated inFIG. 3of the disclosure, the vehicle200has an engine204which is drivingly connected to a transmission206. As non-limiting example, the engine204of the vehicle200may be an internal combustion engine, an electric motor, a steam turbine and/or a gas turbine. A transmission output shaft208is then drivingly connected to an end of the transmission206opposite the engine204. The transmission206is a power management system which provides controlled application of the rotational power generated by the engine204by means of a gear box.

The transmission output shaft208is drivingly connected to a transfer case input shaft210which in turn is drivingly connected to a transfer case212. The transfer case212is used in four-wheel drive and/or all-wheel-drive (AWD) vehicles to transfer the rotational power from the transmission206to a front axle system214and a rear axle system216by utilizing a series of gears and drive shafts. Additionally, the transfer case212allows the vehicle200to selectively operate in either a two-wheel drive mode of a four-wheel/AWD drive mode. As illustrated inFIG. 3of the disclosure and as a non-limiting example, the transfer case212includes a first transfer case output shaft218and a second transfer case output shaft220.

A first shaft222extends from the first transfer case output shaft218toward the front axle system214of the vehicle200. The first shaft222transmits the rotational power from the transfer case212to the front axle system214thereby drivingly connecting the transfer case212to the front axle system214of the vehicle200. It is within the scope of this disclosure and as a non-limiting example that the first shaft222may be a drive shaft, a propeller shaft, a Cardan shaft or a double Cardan shaft.

Drivingly connected to an end of the first shaft222, opposite the first transfer cane output shaft218, is a front axle system input shaft224. The front axle system input shaft224drivingly connects the first shaft222to a front axle differential assembly226of the front axle system214of the vehicle200. As illustrated inFIG. 3of the disclosure and as a non-limiting example, at least a portion of an end of the front axle system input shaft224, opposite the first shaft222, is drivingly connected to the front axle differential assembly226of the vehicle200. It is within the scope of this disclosure and as a non-limiting example that the front axle system input shaft224may be front differential input shaft, a coupling shaft, stub shaft or a front differential pinion shaft. The front axle differential assembly226is a set of gears that allows the outer drive wheel(s) of the vehicle200to rotate at a faster rate that the inner drive wheel(s). The rotational power is transmitted through the front axle system214as described in more detail below.

The front axle system214further includes a first front axle half shaft228and a second front axle half shaft230. As illustrated inFIG. 3of the disclosure and as a non-limiting example, the first front axle half shaft228extends substantially perpendicular to the front axle system input shaft224of the vehicle200. At least a portion of a first end portion232of the first front axle half shaft228is drivingly connected to a first front axle wheel assembly234and at least a portion of a second end portion236of the first front axle half shaft228is drivingly connected to an end of the front axle differential assembly226. It is within the scope of this disclosure and as a non-limiting example that the second end portion236of the first front axle half shaft228may be drivingly connected to a front differential side gear, a separate stub shaft, a separate coupling shaft, a first front axle differential output shaft, a first front axle have shaft connect and disconnect assembly and/or a shaft that is formed as part of a front differential side gear.

Extending substantially perpendicular to the front axle system input shaft224is the second front axle half shaft230of the vehicle200. At least a portion of a first end portion238of the second front axle half shaft230is drivingly connected to a second front axle wheel assembly240of the vehicle200. As illustrated inFIG. 3of the disclosure and as a non-limiting example, at least a portion of a second end portion242of the second front axle half shaft230is drivingly connected to an end of the front axle differential assembly226opposite the first front axle half shaft228. It is within the scope of this disclosure and as a non-limiting example that the second end portion242of the second front axle half shaft230may be drivingly connected to a front differential side gear, a separate stub shaft, a separate coupling shaft, a second front axle differential output shaft, a second front axle half shaft connect and disconnect assembly and/or a shaft that is formed as part of a front differential side gear.

According to the embodiment of the disclosure illustrated inFIG. 3and as a non-limiting example, the front axle system214of the vehicle200may further include the use of one or more front axle differential clutch pack assemblies244. The one or more front axle differential clutch pack assemblies244are used to precisely control the amount of torque that is transferred by the engine204to the first and/or second front axle wheel assemblies234and/or240of the vehicle200. In order to apply an amount of force onto the one or more front axle differential clutch pack assemblies244, one or more front axle system ball and ramp assemblies245are operably connected to at least a portion of the one or more front axle differential clutch pack assemblies244of the vehicle200. The one or more front axle system ball and ramp assemblies245are operably configured to apply a variable amount of force onto the one or more front axle differential clutch pack assemblies244of the front axle system214of the vehicle200.

In order for the one or more front axle system ball and ramp assemblies245to apply a variable amount of force onto the one or more front axle differential clutch pack assemblies244of the vehicle200, a first motor246is drivingly connected to at least a portion of the one or more front axle system ball and ramp assemblies245. It is within the scope of this disclosure and as a non-limiting example that the first motor246of the one or more front axle differential clutch pack assemblies244may be an electric motor, an actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electro-mechanical actuator, an electro-magnetic actuator and/or any other type or motor that is able to convert an amount of energy into mechanical energy.

The one or more front axle system ball and ramp assemblies245and the first motor246of the one or more front axle differential clutch pack assemblies244of the vehicle200are in communication with a control unit248via one or more first data-links250. The one or more first data-links250allow for communication between one or more front axle system ball and ramp assemblies245, the first motor246and the control unit248of the vehicle200. As a non-limiting example, the one or more first data-links250of the vehicle200may be one or more fiber optic cables and/or one or more electrical cables that put the control unit248in optical and/or electrical communication with the first motor246and the one or more front axle system ball and ramp assemblies245of the one or more front axle differential clutch pack assemblies244.

In accordance with the embodiment of the disclosure illustrated inFIG. 3and as a non-limiting example, the control unit248may be in communication with a vehicle bus252via one or more control unit data-links254. It is within the scope of this disclosure and as a non-limiting example that the vehicle bus252may be a Controller Area network (CAN) Bus or a CAN Bus that conforms to the Society of Automotive Engineers (SAE) J-1939 standards. Additionally, it is within the scope of this disclosure and as a non-limiting example that the one or more control unit data-links254may be one or more fiber optic cables and/or one or more electrical cables that put the control unit248in optical and/or electrical communication with the vehicle bus252of the vehicle200.

An end of the second transfer case output shaft220is drivingly connected to an end of the transfer case212opposite the transfer case input shaft210. Extending from the second transfer case output shaft220, toward the rear axle system216of the vehicle200, is a second shaft256. It is within the scope of this disclosure and as a non-limiting example that the second shaft256of the vehicle200may be a drive shaft, a propeller shaft, a Cardan shaft or a double Cardan shaft.

Drivingly connected to an end of the second shaft256, opposite the second transfer case output shaft220, is a rear axle system input shaft258. As a non-limiting example, the rear axle input shaft258may be a rear axle differential input shaft, a coupling shaft, stub shaft or a rear axle differential pinion shaft. Drivingly connected to an end of the rear axle input shaft258, opposite the second shaft256, is a rear axle differential assembly260of the rear axle system216of the vehicle200. The rear axle differential assembly260is a device that divides the rotational power generated by the engine204between the axles in the vehicle200. The rotational power is transmitted through the rear axle system216as described in more detail below.

As illustrated inFIG. 3of the disclosure and as a non-limiting example, the rear axle system216further includes a first rear axle half shaft262and a second rear axle half shaft264. The first rear axle half shaft262extends substantially perpendicular to the rear axle system input shaft258of the vehicle200. At least a portion of a first end portion266of the first rear axle half shaft262is drivingly connected to a first rear axle wheel assembly268and at least a portion of a second end portion270of the first rear axle half shaft262is drivingly connected to an end of the rear axle differential assembly260. It is within the scope of this disclosure and as a non-limiting example that the second end portion270of the first rear axle half shaft262is drivingly connected to a rear axle differential side gear, a separate stub shaft, a separate coupling shaft, a first rear axle differential output shaft, a first rear axle half shaft connect and disconnect assembly and/or a shaft that is formed as part of a rear axle differential side gear.

According to the embodiment of the disclosure illustrated inFIG. 3and as a non-limiting example, the rear axle system216of the vehicle200may further include the use of a first rear axle differential clutch pack assembly272. The first rear axle differential clutch pack assembly272is used to precisely control the amount of torque that is transferred by the engine204to the first rear axle wheel assembly268of the vehicle200. In order to apply an amount of force onto the first rear axle differential clutch pack assembly272, a first rear axle system ball and ramp assembly273is operably connected to at least a portion of the first rear axle differential clutch pack assembly272of the vehicle200. The first rear axle system ball and ramp assembly273is operably configured to apply a variable amount of force onto the first rear axle differential clutch pack assembly272of the rear axle system216of the vehicle200.

In order for the first rear axle system ball and ramp assembly273to apply a variable amount of force onto the first rear axle differential clutch pack assembly272of the vehicle200, a second motor274is drivingly connected to at least a portion of the first rear axle system ball and ramp assembly273. It is within the scope of this disclosure and as a non-limiting example that the second motor274of the first rear axle differential clutch pack assembly272may be an electric motor, an actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electro-mechanical actuator, an electro-magnetic actuator and/or any other type or motor that is able to convert an amount of energy into mechanical energy.

The first rear axle system ball and ramp assembly273and the second motor274of the first rear axle differential clutch pack assembly272of the vehicle200are in communication with the control unit248via one or more second data-links276. The one or more second data-links276allow for communication between first rear axle system ball and ramp assembly273, the second motor274and the control unit248of the vehicle200. As a non-limiting example, the one or more second data-links276of the vehicle200may be one or more fiber optic cables and/or one or more electrical cables that put the control unit248in optical and/or electrical communication with the second motor274and the first rear axle system ball and ramp assembly273of the first rear axle differential clutch pack assembly272.

Extending substantially perpendicular to the rear axle system input shaft258is the second rear axle half shaft264of the vehicle200. At least a portion of a first end portion278of the second rear axle half shaft264is drivingly connected to a second rear axle wheel assembly280of the vehicle200. As illustrated inFIG. 3of the disclosure and as a non-limiting example, at least a portion of a second end portion282of the second rear axle half shaft264is drivingly connected to an end of the rear axle differential assembly260opposite the first rear axle half shaft262. It is within the scope of this disclosure and as a non-limiting example that the second end portion282of the second rear axle half shaft264may be drivingly connected to a rear differential side gear, a separate stub shaft, a separate coupling shaft, a second rear axle differential output shaft, a second rear axle half shaft connect and disconnect assembly and/or a shaft that is formed as part of a rear differential side gear.

According to the embodiment of the disclosure illustrated inFIG. 3and as a non-limiting example, the rear axle system216of the vehicle200may further include the use of a second rear axle differential clutch pack assembly284. The second rear axle differential clutch pack assembly284is used to precisely control the amount of torque that is transferred by the engine204to the second rear axle wheel assembly280of the vehicle200. In order to apply an amount of force onto the second rear axle differential clutch pack assembly284, a second rear axle system ball and ramp assembly285is operably connected to at least a portion of the second rear axle differential clutch pack assembly284of the vehicle200. The second rear axle system ball and ramp assembly285is operably configured to apply a variable amount of force onto the second rear axle differential clutch pack assembly284of the rear axle system216of the vehicle200.

In order for the second rear axle system ball and ramp assembly285to apply a variable amount of force onto the second rear axle differential clutch pack assembly284of the vehicle200, a third motor286is drivingly connected to at least a portion of the second rear axle system ball and ramp assembly285. It is within the scope of this disclosure and as a non-limiting example that the third motor286of the second rear axle differential clutch pack assembly284may be an electric motor, an actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electro-mechanical actuator, an electro-magnetic actuator and/or any other type or motor that is able to convert an amount of energy into mechanical energy.

The second rear axle system ball and ramp assembly285and the third motor285of the second rear axle differential clutch pack assembly284of the vehicle200are in communication with the control unit248via one or more third data-links288. The one or more third data-links288allow for communication between second rear axle system ball and ramp assembly285, the third motor286and the control unit248of the vehicle200. As a non-limiting example, the one or more third data-links288of the vehicle200may be one or more fiber optic cables and/or one or more electrical cables that put the control unit248in optical and/or electrical communication with the third motor286and the second rear axle system ball and ramp assembly285of the second rear axle differential clutch pack assembly284.

While the embodiment of the disclosure illustrated inFIG. 3illustrates the motors246,274and286and the ball and ramp assemblies245,273and285as being in electrical and/or optical communication with the control unit248, it is within the scope of this disclosure that one or more of the motors246,274and286and the ball and ramp assemblies245,273and285may be in wireless communication with the control unit248. As a non-limiting example the wireless communication between the motors246,274and/or286, the ball and ramp assemblies245,273and/or285and the control unit248may be a Bluetooth connection, a Wi-fi connection, a cellular connection and/or a radio wave connection. As a result, it is within the scope of this disclosure that the one or more of the motors246,274and/or286, the ball and ramp assemblies245,273and/or285and the control unit248may be operably configured to send and/or receive the data and/or instructions needed for the operation of clutch pack assemblies244,272and/or284of the vehicle200. Additionally, as a result, it is within the scope of this disclosure and as a non-limiting example that the motors246,274and/or286, the ball and ramp assemblies245,273and/or285and the control unit248may be operably configured to send and/or receive the data and/or instructions needed in order to determine if a ball loss has occurred or to predict when a ball loss will occur within one or more of the ball and ramp assemblies245,273and/or285.

Furthermore, while the embodiment of the disclosure illustrated inFIG. 3illustrates the control unit248being in electrical and/or optical communication with the vehicle bus252of the vehicle200, it is within the scope of this disclosure that the control unit248may be wireless communication with the vehicle bus252. As a non-limiting example the wireless communication between the control unit248and the vehicle bus252may be a Bluetooth connection, a Wi-fi connection, a cellular connection and/or a radio wave connection. As a result, it is within the scope of this disclosure that the control unit248and the vehicle bus252may be operably configured to send and/or receive the data and/or instructions needed for the operation of the clutch pack assemblies244,272and/or284of the vehicle200. Additionally, as a result, it is within the scope of this disclosure and as a non-limiting example that the control unit248and the vehicle bus252may be operably configured to send and/or receive the data and/or instructions needed in order to determine if a ball loss has occurred or to predict when a ball loss will occur within one or more of the ball and ramp assemblies245,273and/or285.

It is within the scope of this disclosure and as a non-limiting example that a ball loss within one or more of the ball and ramp assemblies245,273and/or285may be determined using a ball loss detection method according to an embodiment of the disclosure. Additionally, it is within the scope of this disclosure and as a non-limiting example that one or more of the ball and ramp assemblies245,273and/or285may utilize a method of predicting a ball loss condition according to an embodiment of the disclosure.

FIG. 4is a schematic top-plan view of still yet another vehicle300having one or more drive units with one or more ball and ramp assemblies utilizing a method of determining if a ball loss has occurred and/or when a ball loss will occur according to an embodiment of the disclosure. The vehicle300illustrated inFIG. 4is the same as the vehicle200illustrated inFIG. 2, except where specifically noted below. As illustrated inFIG. 4of the disclosure and as a non-limiting example, the vehicle300does not include the use of the transfer case212that is drivingly connected to at least a portion of the front axle system differential assembly226having the one or more front axle differential clutch pack assemblies244.

In accordance with the embodiment of the disclosure illustrated inFIG. 3of the disclosure and as a non-limiting example, at least a portion of the end of the transmission output shaft208, opposite the transmission206, is drivingly connected to at least a portion of the end of the second shaft265opposite the rear axle system input shaft258. As a result, in accordance with the embodiment of the disclosure illustrated inFIG. 4and as a non-limiting example, the second shaft256of the vehicle300extends from the transmission output shaft208toward the rear axle differential assembly260of the rear axle system216of the vehicle300.

It is within the scope of this disclosure and as a non-limiting example that a ball loss within one or more of the ball and ramp assemblies273and/or285may be determined using a ball loss detection method according to an embodiment of the disclosure. Additionally, it is within the scope of this disclosure and as a non-limiting example that one or more of the ball and ramp assemblies273and/or285may utilize a method of predicting a ball loss condition according to an embodiment of the disclosure.

FIG. 5is a schematic top-plan view of a drive unit assembly400with one or more clutch pack assemblies402with one or more ball and ramp assemblies403according to an embodiment of the disclosure. As illustrated inFIG. 5of the disclosure and as a non-limiting example, the drive unit assembly400includes a pinion gear404that is drivingly connected to and meshingly engaged with a ring gear406of a differential assembly408. At least a portion of a pinion gear shaft410is rotationally supported within one or more pinion shaft bearings412of the drive unit assembly400. It is within the scope of this disclosure and as a non-limiting example that the differential assembly408of the drive unit assembly400may be a front axle differential assembly, a rear axle differential assembly, a forward tandem axle differential assembly and/or a rear tandem axle differential assembly of a vehicle (not shown).

At least a portion of an end of the pinion shaft410, opposite the pinion gear404is drivingly connected to a source of rotational power (not shown). It is within the scope of this disclosure and as a non-limiting example that the source (not shown) may be an engine, a transmission, a transfer case, a propeller shaft a drive shaft, universal joint assembly and/or a constant velocity joint assembly.

Drivingly connected to at least a portion of the ring gear408of the differential assembly408is a differential case414having an inner surface416, an outer surface418, a first end portion420and a second end portion422. The inner surface416and the outer surface418of the differential case414defines a hollow portion424therein. Disposed with in at least a portion of the hollow portion424of the differential case414is a differential gear set426having a first side gear428, a second side gear430and one or more bevel gears432that are drivingly and meshingly engaged with the first and second side gears428and430of the differential gear set426.

Extending co-axially with at least a portion of the second side gear430of the differential assembly408is a second axle half shaft434having a first end portion (not shown) and a second end portion436. As illustrated inFIG. 5and as a non-limiting example, at least a portion of the second end portion436of the second axle half shaft434is drivingly connected to at least a portion of the second side gear430of the differential assembly408. At least a portion of the first end portion (not shown) of the second axle half shaft434is drivingly connected to at least a portion of a second wheel assembly (not shown). It is within the scope of this disclosure and as a non-limiting example that the second axle half shaft434may be a second front axle half shaft, a second rear axle half shaft, a second forward tandem axle half shaft and/or a second rear tandem axle half shaft.

At least a portion of the second axle half shaft434is rotationally supported by a second axle half shaft bearing438. In accordance with the embodiment of the disclosure illustrated inFIG. 8and as a non-limiting example, at least a portion of the second axle half shaft bearing438is interposed between the second axle half shaft434and first reduced diameter portion440of the differential case414. The first reduced diameter portion440of the differential case414extends axially outboard from at least a portion of the first end portion420of the differential case414.

Disposed radially outboard from at least a portion of the first reduced diameter portion440of the differential case414is a first differential case bearing442. As illustrated inFIG. 5of the disclosure and as a non-limiting example, at least a portion of the first differential case bearing442is interposed between the differential case414and an inner surface444of a housing446of the drive unit assembly400. The first differential case bearing442of the drive unit assembly400provides rotational support for at least a portion of the first end portion420of the differential case414. Additionally, it is within the scope of this disclosure and as a non-limiting example the first differential case bearing442may also provide axial load support for the differential case414allowing for rotation of the differential case414relative to the housing446of the drive unit assembly400when in operation.

A second differential case bearing443is interposed between the outer surface418of a second reduced diameter portion445of the differential case414and the inner surface444the housing446of the drive unit assembly400. In accordance with the embodiment of the disclosure illustrated inFIG. 5and as a non-limiting example, the second reduced diameter portion445of the differential case414extends axially outboard from at least a portion of the second end portion422of the differential case414. The second differential case bearing443of the drive unit assembly400provides rotational support for at least a portion of the second end portion422of the differential case414. Additionally, it is within the scope of this disclosure and as a non-limiting example the second differential case bearing443may also provide axial load support for the differential case414allowing for rotation of the differential case414relative to the housing446of the drive unit assembly400when in operation.

Extending co-axially with at least a portion of the first side gear428of the differential assembly408is a first axle half shaft448having a first end portion450, a second end portion452and an intermediate portion454interposed between the first and second end portions450and452of the first axle half shaft448. As illustrated inFIG. 5of the disclosure and as a non-limiting example, at least a portion of the first end portion450of the first axle half shaft448is drivingly connected to at least a portion of the first side gear428of the differential assembly408of the drive unit assembly400. At least a portion of the second end portion452of the first axle half shaft448is drivingly connected to at least a portion of a first wheel assembly (not shown). It is within the scope of this disclosure and as a non-limiting example that the first axle half shaft448may be a first front axle half shaft, a first rear axle half shaft, a first forward tandem axle half shaft and/or a first rear tandem axle half shaft.

Drivingly connected to at least a portion of the first axle half shaft448and the differential case414of the differential assembly408is the one or more clutch pack assemblies402of the drive unit assembly400. As illustrated inFIG. 5of the disclosure and as a non-limiting example, the one or more clutch pack assemblies402have a clutch can456, a clutch drum458, a first plurality of clutch plates460and a second plurality of clutch plates462. At least a portion of the clutch drum458of the one or more clutch pack assemblies402extends co-axially with at least a portion of the first axle half shaft448and the differential case414. The clutch drum458has a first end portion464, a second end portion466, an inner surface468and an outer surface470defining a hollow portion472therein. In accordance with the embodiment of the disclosure illustrated inFIG. 5and as a non-limiting example, at least a portion of the first end portion464of the clutch drum458is integrally connected to at least a proton of the second end portion422of the differential case414.

Interposed between the first end portion464of the clutch drum458and the housing446is a first thrust bearing474. The first thrust bearing474of the one or more clutch pack assemblies402of the drive unit assembly400allows for relative rotation and reduces the overall amount of friction between the clutch drum458and the housing446of the drive unit assembly400.

Drivingly connected to at least a portion of the inner surface468of the clutch drum458of the one or more clutch pack assemblies402is the first plurality of clutch plates460. Additionally, the first plurality of clutch plates460of the one or more clutch pack assemblies402are mounted to the clutch drum458so as to allow the first plurality of clutch plates460to slide axially along the inner surface468of the clutch drum458while remaining drivingly connected to the clutch drum458.

Extending co-axially with at least a portion of the first axle half shaft448and the clutch drum458is the clutch can456of the one or more clutch pack assemblies402of the drive unit assembly400. As illustrated inFIG. 5of the disclosure and as a non-limiting example, at least a portion of the clutch can456of the one or more clutch pack assemblies402is disposed within the hollow portion472of the clutch drum458. A radially extending portion478extends radially inward from at least a portion of an inner surface480of the clutch can456of the one or more clutch pack assemblies402. An end of the radially extending portion478, opposite the clutch can456, is drivingly connected to at least a portion of the intermediate portion454of the first axle half shaft448of the drive unit assembly400. It is within the scope of this disclosure and as a non-limiting example that the radially extending portion478of the clutch can456may be connected to at least a portion of the first axle half shaft448by using one or more mechanical fasteners, one or more adhesives, one or more welds, a spline connection and/or a threaded connection.

Drivingly connected to at least a portion of an outer surface482of the clutch can656of the one or more clutch pack assemblies402is the second plurality of clutch plates462. Additionally, the second plurality of clutch plates462of the one or more clutch pack assemblies462are mounted to the clutch can456so as to allow the second plurality of clutch plates462to slide axially along the outer surface482of the clutch can456while remaining drivingly connected to the clutch can456. As illustrated inFIG. 5of the disclosure and as a non-limiting example, the second plurality of clutch plates462are interleafed with the first plurality of clutch plates460of the one or more clutch pack assemblies402. It is within the scope of this disclosure and as a non-limiting example that the one or more clutch pack assemblies402may further include the use of one or more biasing members (not shown) that are interposed between one or more of the first and second plurality of clutch plates460and462.

Disposed axially outboard from at least a portion of the clutch can456and the clutch drum458is the one or more ball and ramp assemblies403of the one or more clutch pack assemblies402of the drive unit assembly400. The one or more ball and ramp assemblies403are selectively engageable with the first and/or second plurality of clutch plates460and/or462of the one or more clutch pack assemblies402. In accordance with the embodiment of the disclosure illustrated inFIG. 5and as a non-limiting example, the one or more ball and ramp assemblies403includes a first plate486, a second plate488and one or more balls490interposed between the first plate486and the second plate488.

The first plate486of the one or more ball and ramp assemblies403resists the axial force applied thereto thereby allowing the second plate488to translate axially toward the first and second plurality of clutch plates460and462of the one or more clutch pack assemblies402of the drive unit assembly400. It is within the scope of this disclosure and as a non-limiting example that the first plate486of the one or more ball and ramp assemblies403may be rotatable, non-rotatable and integrally connected to at least a portion of the housing446or non-rotatable and forms a part of the housing446of the drive unit assembly400. Additionally, it is within the scope of this disclosure and as a non-limiting example that the first plate486of the one or more ball and ramp assemblies403may be a pressure plate.

Interposed between the second plate488and the first plate486of the one or more ball and ramp assemblies403or between the second plate488and the housing446of the drive unit assembly400is a bearing492. The bearing492allows for relative rotation of the second plate488and the first plate486and/or the housing446of the drive unit assembly400when in operation.

As illustrated inFIG. 5of the disclosure and as a non-limiting example, the second plate488of the one or more ball and ramp assemblies403has an inner surface494, an outer surface496a first side498and a second side500. Circumferentially extending along at least a portion of the outer surface496of the second plate488of the one or more ball and ramp assemblies403is a plurality of actuator plate teeth502. It is within the scope of this disclosure and as a non-limiting example that the second plate488of the one or more ball and ramp assemblies403may be an actuator plate.

At least a portion of one or more of the one or more balls490of the one or more ball and ramp assemblies403are disposed within one or more first plate grooves501in the first plate486and one or more second plate grooves503in the second plate488. The one or more first and second plate grooves501in the first plate486are complementary to the one or more second plate grooves503in the second plate488of the one or more ball and ramp assemblies403of the drive unit assembly400. Additionally, the one or more second plate grooves503are in the second side500of the second plate488and the one or more first plate grooves501are in a side of the first plate486facing the second plate488of the one or more ball and ramp assemblies403. Furthermore, the one or more first plate grooves501and the one or more second plate grooves503have a variable depth such that when the second plate488is rotated, the second plate488is translated axially away from the first plate486toward the first and second plurality of clutch plates460and462of the one or more clutch pack assemblies402of the drive unit assembly400. It is within the scope of this disclosure and as a non-limiting example that the one or more first and second plate grooves501and503in the first and second plates486and488may be disposed along one or more fixed or variable radii from the theoretical center of the first and second plates486and488of the one or more ball and ramp assemblies403.

Interposed between the second plate488and the first and second plurality of clutch plates460and462of the one or more clutch pack assemblies402is a second thrust bearing504. The second thrust bearing504of the one or more clutch pack assemblies402of the drive unit assembly400allows for relative rotation and reduces the overall amount of friction between the second plate488and the first and second plurality of clutch plates460and462of the one or more clutch pack assemblies402. When in operation, the second plate488will translate the second thrust bearing504axially toward the first and second plurality of clutch plates460and462until at least a portion of the second thrust bearing504is in direct contact with at least a portion of the first and/or second plurality of clutch plates460and462. Once the second thrust bearing504is in direct contact with the first and/or second plurality of clutch plates460and462, the force from the second plate488will be transmitted to the first and second plurality of clutch plates460and462via the second thrust bearing504. This allows the one or more clutch pack assemblies402of the drive unit assembly400to precisely control the amount of torque that is transferred by an engine (not shown) to the wheel assemblies (not shown) of the vehicle (not shown).

Disposed radially outboard from at least a portion of the second plate488of the one or more ball and ramp assemblies403is one or more motors506and one or more gear sets508. Drivingly connected to at least a portion of the one or more motors506of the drive unit assembly400is a motor output shaft510. It is within the scope of this disclosure and as a non-limiting example that the one or more motors506may be an electric motor, an actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, an electro-mechanical actuator, an electro-magnetic actuator and/or any other type or motor that is able to convert an amount of energy into mechanical energy.

At least a portion of an end of the motor output shaft510, opposite the one or more motors506, is drivingly connected to at least a portion of a first gear512of the one or more gear sets508. It is within the scope of this disclosure and as a non-limiting example that the first gear512may be connected to at least a portion of the motor output shaft510by using one or more mechanical fasteners, one or more welds, one or more adhesives, a splines connection and/or a threaded connection.

A second or intermediate gear514of the one or more gear sets508is drivingly connected to and disposed radially inboard from at least a portion of the first gear512of the one or more gear sets508. Circumferentially extending from at least a portion of an outer surface516of the second or intermediate gear514is a plurality of second gear teeth518. The plurality of second gear teeth518of the second or intermediate gear514are complementary to and meshingly engaged with a plurality of first gear teeth520circumferentially extending from at least a portion of an outer surface522of the first gear512.

Drivingly connected to at least a portion of an inner surface524of the second or intermediate gear514is a gear shaft526. At least a portion of the gear shaft526of the one or more gear sets508is rotationally supported by a support shaft528. As illustrated inFIG. 5of the disclosure and as a non-limiting example, the support shaft528extends axially inboard from at least a portion of an inner surface530of the housing446of the drive unit assembly400. It is within the scope of this disclosure and as a non-limiting example that at least a portion of the support shaft528may be integrally connected to at least a portion of the inner surface530of the housing446by using one or more mechanical fasteners, one or more welds, one or more adhesives and/or by using a threaded connection. Additionally, it is within the scope of this disclosure and as a non-limiting example that the support shaft528may be integrally formed as part of the inner surface530of the housing546of the drive unit assembly500.

As illustrated inFIG. 5of the disclosure and as a non-limiting example, at least a portion of a third gear532is drivingly connected to at least a portion of an end of the gear shaft526opposite the second or intermediate gear514of the one or more gear sets508. Circumferentially extending along at least a portion of an outer surface534of the third gear532is a plurality of third gear teeth536. The plurality of third gear teeth536of the third gear532are complementary to and meshingly engaged with the plurality of actuator plate teeth502of the second plate488of the one or more ball and ramp assemblies403. As a result, the third gear532drivingly connects the one or more motors506to the second plate488of the one or more ball and ramp assemblies403of the drive unit assembly400.

In accordance with the embodiment of the disclosure illustrated inFIG. 5and as a non-limiting example, the one or more motors506of the drive unit assembly400may further include the use of one or more first sensors538. The one or more first sensors538of the one or more motors506are disposed radially outboard from at least a portion of the motor output shaft510and are operably configured to detect and/or determine the position of the motor output shaft510. It is within the scope of this disclosure and as a non-limiting example that the one or more first sensors538of the one or more motors506may be one or more Hall Effect sensors, one or more Hall sensors, one or more rotary encoders, one or more proximity sensors, one or more capacitive displacement sensors and/or any other type of sensor that is able to detect and/or determine the position of the motor output shaft510of the drive unit assembly400.

The one or more motors506and the one or more first sensors538in the one or more motors506are in communication with one or more control units540via one or more motor data-links542. The one or more motor data-links542allow for communication between the one or more motors506and the one or more control units540. Additionally, the one or more motor data-links542allow for communication between the one or more first sensors538of the one or more motors506and the one or more control units540. As a non-limiting example the one or more motor data-links542may be one or more fiber optic cables and/or one or more electrical cables that put the one or more control units540in optical and/or electrical communication with the one or more motors506and the one or more first sensors538of the one or more motors506.

As illustrated inFIG. 5of the disclosure and as a non-limiting example, the one or more control units540may further include the use of one or more second sensors544and/or one or more data processors546. The one or more second sensors544of the one or more control units540are operably configured to detect and/or determine the amount of current being supplied to the motor502of the drive unit assembly400. It is within the scope of this disclosure and as a non-limiting example that the one or more second sensors544of the one or more control units540may be one or more Hall Effect current sensors, one or more Hall current sensors, one or more resistors and/or any other type of sensor that is able to detect and/or determine the amount of electrical current in one or more wires supplying the one or more motors506with power.

The one or more data processors546of the one or more control units540are operably configured to collect and/or analyze the data collected by the one or more first and second sensors538and544in order to determine whether or not a ball loss has occurred within the one or more ball and ramp assemblies403of the drive unit assembly400. Additionally, the one or more data processors546of the one or more control units540are operably configured to collect and/or analyze the data collected by the one or more first and second sensors538and544in order to predict when a ball loss will occur within the one or more ball and ramp assemblies403of the drive unit assembly400. It is therefore within the scope of this disclosure and as a non-limiting example that the one or more control units540may be operably configured to determine and/or predict a ball loss condition within the one or more ball and ramp assemblies403of the drive unit assembly400.

In accordance with the embodiment of the disclosure illustrated inFIG. 5of the disclosure and as a non-limiting example, the one or more control units540may be in communication with a vehicle bus548via one or more control unit data-links550. The one or more control unit data-links550allow for communication between the one or more control units540and the vehicle bus550. Additionally, the one or more control unit data-links550allow for communication between the one or more first sensors538of the one or more motors506and the one or more control units540and the vehicle bus548. As a non-limiting example the one or more control unit data-links550may be one or more fiber optic cables and/or one or more electrical cables that put the vehicle bus548in optical and/or electrical communication with the one or more control units540, the one or more second sensors544of the one or more control units540and the one or more first sensors538of the one or more motors506. It is within the scope of this disclosure and as a non-limiting example that the vehicle bus548may be a CAN Bus or a CAN Bus that conforms to the SAE J-1939 standards.

As illustrated inFIG. 5of the disclosure and as a non-limiting example, the vehicle bus548may further include the use of one or more data processors552that are operably configured to collect and/or analyze the data collected from the one or more first and second sensors438and444in order to determine whether or not a ball loss has occurred within the one or more ball and ramp assemblies403of the drive unit assembly400. Additionally, as illustrated inFIG. 5of the disclosure and as a non-limiting example, the vehicle bus548may further include the use of one or more data processors552that are operably configured to collect and/or analyze the data collected from the one or more first and second sensors438and444in order to predict when a ball loss will occur within the one or more ball and ramp assemblies403of the drive unit assembly400. It is therefore within the scope of this disclosure and as a non-limiting example that the vehicle bus548may be operable configured to determine and/or predict a ball loss condition within the one or more ball and ramp assemblies403of the drive unit assembly400. As a result, it is within the scope of this disclosure and as a non-limiting example that the one or more control units540and/or the vehicle bus548may be used in order to determine and/or predict a ball loss condition within the one or more ball and ramp assemblies403of the drive unit assembly400.

While the embodiment of the disclosure illustrated inFIG. 5illustrates the one or more motors506and the one or more first sensors538as being in electrical and/or optical communication with the one or more control units540, it is within the scope of this disclosure that the one or more motors506and the one or more first sensors538may be in wireless communication with the one or more control units540. As a non-limiting example the wireless communication between the one or more motors506and the one or more first sensors538and the one or more control units540may be a Bluetooth connection, a Wi-fi connection, a cellular connection and/or a radio wave connection. As a result, it is within the scope of this disclosure that the one or more motors506, the one or more first sensors538and the one or more control units540may be operably configured to send and/or receive the data and/or instructions needed for the operation of the one or more clutch pack assemblies402of the drive unit400. Additionally, it is therefore within the scope of this disclosure and as a non-limiting example that the one or more motors506, the one or more first sensors538and the one or more control units540may be operably configured to send and/or receive the data and/or instructions needed in order to determine and/or predict a ball loss condition within the one or more ball and ramp assemblies403of the drive unit assembly400.

Furthermore, while the embodiment of the disclosure illustrated inFIG. 5illustrates the one or more control units540being in electrical and/or optical communication with the vehicle bus548, it is within the scope of this disclosure that the one or more control units540, the one or more motors506, the one or more first sensors538and the one or more second sensors544may be wireless communication with the vehicle bus548. As a non-limiting example the wireless communication between the one or more control units540, the one or more motors506, the one or more first sensors538and the one or more second sensors544and the vehicle bus548may be a Bluetooth connection, a Wi-fi connection, a cellular connection and/or a radio wave connection. As a result, it is within the scope of this disclosure that the one or more control units540, the one or more motors506, the one or more first sensors538, the one or more second sensors544and/or the vehicle bus548may be operably configured to send and/or receive the data and/or instructions needed for the operation of the one or more clutch pack assemblies402. Additionally, it is therefore within the scope of this disclosure and as a non-limiting example that the one or more control units540and/or the vehicle bus548may be operably configured to send and/or receive the data and/or instructions needed in order to determine and/or predict a ball loss condition within the one or more ball and ramp assemblies403of the drive unit assembly400.

FIGS. 6-8illustrate a method of determining a ball loss condition within one or more ball and ramp assemblies403of the drive unit assembly400according to an embodiment of the disclosure. As previously discussed, the one or more ball and ramp assemblies403of the one or more clutch pack assemblies402are used in order to translate the rotational motion of the one or more motors506into an axial motion that will apply a variable amount of force onto the plurality of first and second clutch plates460and462of the one or more clutch pack assemblies402. Additionally, as previously discussed, the one or more clutch pack assemblies402of the drive unit assembly400are used to precisely control the amount of torque that is transmitted from the engine (not shown) to one or more of the wheel assemblies (not shown) of the vehicle (not shown) by applying a variable amount of force onto the first and second plurality of clutch plates460and462by the one or more ball and ramp assemblies403.

In order for the one or more ball and ramp assemblies403to apply a variable amount of force onto the first and/or second plurality of clutch plates460and/or462, the one or more motors506selectively rotate the motor output shaft510which drives the one or more gear sets508which in turn selectively rotates the first and/or second plates486and/or488of the one or more ball and ramp assemblies403. As the first and/or the second plate486and/or488of the one or more ball and ramp assemblies403are rotated, the one or more balls490are translated from their home position or pocket (not shown) along the update slope of the one or more first and second plate grooves501and503in the first and second plates486and488. As the one or more balls490travel along the one or more first and second plate grooves501and503of the first and second plates486and488, the gap between the first plate486and the second plate488increases as the second plate488and the second thrust bearing504is translated axially toward the first and second plurality of clutch plates460and460of the one or more clutch pack assemblies402. Once the second thrust bearing504is in direct contact with at least a portion of the first and/or second plurality of clutch plates460and462the one or more ball and ramp assemblies403and the one or more motors506begin to apply a variable amount of force onto the one or more clutch pack assemblies402thereby providing the drive unit assembly400with the desired amount of clutch torque or torque vectoring capabilities.

As the one or more balls490of the one or more ball and ramp assemblies403travel along slope of the one or more first and second plate grooves501and503of the first and second plates486and488, one or more of the one or more balls490may lose their desired position and fall back down the slope of the one or more first and second plate grooves501and503toward their home position (not shown). This loss of position is referred to a ball loss condition thereby reducing and/or completely eliminating the ability of the one or more clutch pack assemblies402to provide the desired amount of torque vectoring capabilities to the drive unit assembly400. It is therefore to be understood that when the one or more ball and ramp assemblies403experience a ball loss condition, one or more of the one or more balls490have translated down the slope of the one or more first and second plate grooves501and503of the first and second plates486and488toward their home position (not shown).

In order to identify or determine the occurrence of a ball loss condition602within the one or more ball and ramp assemblies403of the drive unit assembly400, a method of detecting a ball loss condition600is run. As illustrated inFIG. 6of the disclosure and as a non-limiting example, the method of detecting a ball loss condition600first includes a data gathering step604. As part of the data gathering step604, one or more actuation profiles606are run by the one or more motors506of the one or more clutch pack assemblies402of the drive unit assembly400. During the running of the one or more actuation profiles606, one or more cycles are run by the one or more motors506to have the one or more ball and ramp assemblies403apply a variable amount of force onto the first and/or second plurality of clutch plates460and/or462of the one or more clutch pack assemblies402of the drive unit assembly400.

While the one or more actuation profiles606are ran, the one or more first and second sensors538and544measure one or more pre-determined parameters or variables608. As illustrated inFIG. 6of the disclosure and as a non-limiting example, during the measuring of the one or more pre-determined parameters step608of the method of detecting a ball loss condition600, the one or more second sensors544may continuously or at pre-determined intervals measure an amount of current610being used by the one or more motors506while the one or more actuation profiles606are being ran. Additionally, during the measuring of the one or more pre-determined parameters or variables step608, the one or more first sensors538may continuously or at pre-determined intervals measure a position612of the motor output shaft510while the one or more actuation profiles606are being run.

Once the one or more pre-determined parameters or variables608are measured by the one or more first and second sensors538and544, the one or more pre-determined parameters or variables608are sent614to one or more data buffers616in the one or more control units540. The one or more data buffers616of the one or more control units540is a region of physical memory storage that is used to temporarily store the one or more pre-determined parameters or variables608during the data gathering step604while it is being transferred from one location to another within the one or more control units540and/or the vehicle bus548of the vehicle (not shown). It is within the scope of this disclosure and as a non-limiting example that the data gathered during the data gathering step604may be received by the one or more data processors546and/or552of the one or more control units540and/or the vehicle bus548for analysis according to the method of detecting a ball loss condition600described herein.

According to an embodiment of the disclosure and as a non-limiting example, the method of detecting a ball loss condition600may further include the step of averaging618the one or more pre-determined parameters or variables measured608by the one or more first and second sensors538and544. This will provide a mean value for the one or more pre-determined parameters measured608during the one or more actuation profiles606ran thereby providing an average profile for the one or more clutch pack assemblies402of the drive unit400.

After the data gathering step604has been completed, one or more motor current vs. motor output shaft position plots are generated620in order to provide a force vs. position behavior for the one or more ball and ramp assemblies403using one or more motors506. It is within the scope of this disclosure and as a non-limiting example, that the data gathered during the data gathering step604may be received and analyzed by the one or more data processors546and/or552of the one or more control units540and/or the vehicle bus548.FIG. 7of the disclosure provides a graphical representation of an exemplary motor current vs. motor output shaft position plot621generated in accordance with the method of detecting a ball loss condition600described herein. As illustrated inFIG. 7of the disclosure and as a non-limiting example, the data gathered during the data gathering step604of the method of detecting a ball loss condition600generates one or more characteristic curves622. The one or more characteristic curves622of the one or more motor current vs. motor output shaft position plots621define an ideal operation condition for the one or more motors506and the one or more ball and ramp assemblies403of the drive unit400.

Throughout the operation of the drive unit assembly400, one or more first sensors538measure, either continuously or at pre-determined intervals, the position of the motor output shaft510of the one or more motors506. Additionally, the one or more second sensors54of the control unit540measure, either continuously or at pre-determined intervals, the amount of current being used by the one or more motors506of the one or more ball and ramp assemblies403. This data gathered is then plotted on the one or more motor current vs. motor output shaft position plots621as one or more curves623for analysis according to the method of detecting a ball loss condition600described herein.

As it can be seen by referencingFIG. 7of the disclosure and as a non-limiting example, then the one or more ball and ramp assemblies403are in their home position624, the amount of current needed to achieve that position by the motor output shaft510of the one or more motors506is at its lowest. Once the one or more ball and ramp assemblies403reach a kiss point626for the one or more clutch assemblies402, the amount of current needed to achieve each position of the one or more ball and ramp assemblies403increases. It is to be understood that the kiss point626is the point at which the one or more ball and ramp assemblies403and/or the second thrust bearing504begin to apply an amount of force onto the first and/or second plurality of clutch plates460and/or462of the one or more clutch pack assemblies402of the drive unit assembly400.

In the region628between home position624and the kiss point626, the one or more balls490of the one or more ball and ramp assemblies403are being translated up the incline of the one or more first and second plate grooves501and503thereby translating the second plate488axially toward the first and second plurality of clutch plates460and462. Since in this region the one or more ball and ramp assemblies403and/or the second thrust bearing504are not applying an amount of force onto the first and/or second plurality of clutch plates460and/or462of the one or more clutch pack assemblies402, the amount of current needed to achieve these positions are substantially the same.

When the motor output shaft510of the one or more motors506are at a position630illustrated inFIG. 7of the disclosure and as a non-limiting example, the one or more ball and ramp assemblies403and/or the second thrust bearing504are applying a pre-determined maximum amount of force onto the first and/or second plurality of clutch plates460and/or462of the one or more clutch pack assemblies402. At the position630illustrated inFIG. 7and as a non-limiting example, the amount of current needed to achieve that position of the motor output shaft510of the one or more motors506is at its maximum.

In the region632between the kiss point626and the position630illustrated inFIG. 7and as a non-limiting example, the one or more ball and ramp assemblies403and/or the second thrust bearing504are applying an increasing amount of force onto the first and/or second plurality of clutch plates460and/or462of the one or more clutch pack assemblies402. It is therefore to be understood that as the amount of force applied by the one or more ball and ramp assemblies403and/or the second thrust bearing504increases, the amount of current needed to achieve those positions of the motor output shaft510of the one or more motors506increases exponentially.

Once the one or more pre-determined parameters have been measured608by the one or more first and second sensors538and544, an amount of force is determined634. The amount of force determined634relates to the amount of force applied by the one or more ball and ramp assemblies403onto the first and/or second plurality of clutch plates460and/or462of the one or more clutch pack assemblies402during the running of the one or more actuation profiles606. In accordance with an embodiment of the disclosure and as a non-limiting example, the amount of force634applied by the one or more ball and ramp assemblies403onto the one or more clutch pack assemblies402may be determined by utilizing the motor current610and the motor output shaft position612data measured during the running of the one or more actuation profiles606. The amount of torque Tmgenerated by the one or more motors506of the drive unit assembly400is proportional to the amount of current Amused by the one or more motors506during the running of the one or more actuation profiles606. As a result, the amount of torque Tmgenerates by the one or more motors506may be determined by
Tm=Am*CTm
where CTmis a motor torque constant for the one or more motors506of the one or more ball and ramp assemblies403of the drive unit assembly400. The amount of force FBRapplied by the one or more ball and ramp assemblies403may then be determined based on one or more angles θ1of the first and/or second plates486and/or488of the one or more ball and ramp assemblies402, an amount of internal friction within the one or more ball and ramp assemblies403, a gear ratio X for the one or more gear sets508and the amount of torque Tmdetermined. As a result, the amount of force FBRmay be determined634by
FBR=θ1*X*Tm
where the one or more angles θ1relate to the rotational degree to which the one or more motors506have rotated the first and/or the second plates486and/or488away from their home position (not shown). It is within the scope of this disclosure and as a non-limiting example that one or more of the one or more data processors546and/or552of the one or more control units540and/or the vehicle bus548may be used in order to determine the amount of force634applied by the one or more ball and ramp assemblies403onto the one or more clutch pack assemblies402.

When the one or more ball and ramp assemblies403experience a ball loss condition602, the amount of current needed to achieve a given position decreases. This reduction in the amount of current needed for the one or more motors506to achieve a desired position of the motor output shaft510can be seen inFIG. 8of the disclosure.FIG. 8of the disclosure provides a graphical representation of an exemplary motor current vs. motor output shaft position plot636generated in accordance with the method of detecting a ball loss condition600described herein. As it can be seen by referencingFIG. 8of the disclosure and as a non-limiting example, the motor current vs. motor output shaft position plot636includes one or more first curves638and one or more second curves640. The one or more first curves638of the motor current vs. motor output shaft position plot636graphically illustrates the one or more ball and ramp assemblies403in normal operation and not experiencing the ball loss condition602. The one or more second curves640of the motor current vs. motor output shaft position plot636graphically illustrates the one or more ball and ramp assemblies403experiencing one or more of the ball loss conditions602. As it can be seen by referencingFIG. 8of the disclosure and as a non-limiting example, there is a reduction in the amount of current needed to achieve a desired position of the motor output shaft510during the occurrence of the ball loss condition602.

While a reduction in current can be an indication of the occurrence of the ball loss condition602within the one or more ball and ramp assemblies403, this alone is not enough to provide a positive determination as to whether or not the ball loss condition602has in fact occurred. In fact, additional considerations such as but not limited to, velocity and acceleration effects on the amount of current being used by the one or more motors506need to be taken into consideration. Otherwise, a false positive ball loss condition can and will occur. For example, when the one or more motors506are accelerating, it could mask the occurrence of or prevent the detection of the ball loss condition602within the one or more ball and ramp assemblies403of the drive unit assembly400. As a result, it is to be understood that the amount of current drawn by the one or more motors506at a given position of the motor output shaft510alone will not provide a positive determination as to whether or not the ball loss condition602has in fact occurred.

After the amount of force has been determined634, the step of checking for a ball loss condition642is performed. During the ball loss condition checking step642, the one or more control units540and/or the vehicle bus548monitor continuously or at pre-determined intervals the amount of force634being applied by the one or more ball and ramp assemblies403onto the first and/or second plurality of clutch plates460and/or462. Additionally, during the ball loss condition checking step642, the one or more control units540and/or the vehicle bus548monitor continuously or at pre-determined intervals the motor output shaft position requests sent to the one or more motors506to have the one or more ball and ramp assemblies403apply an amount of force onto the first and/or second plurality of clutch pates460and/or462. If the amount of force/position requests or the amount of torque/position requests exceed a pre-determined threshold, then one or more checks are run644in order to prevent the false identification of a ball loss condition within the one or more ball and ramp assembles403of the drive unit assembly400.

Once the one or more motor current vs. motor output shaft position plots621have been generated620, a comparison step646is performed. During the comparison step646, the amount of motor current measured610and/or the amount of force determined632for the one or more curves623of the motor current vs. motor output shaft position plots621is compared to the one or more characteristic curves622previously generated. If the amount of current measured610for the one or more curves623is less than the characteristic amount of current determined for that given motor output shaft position within the one or more characteristic curves622, then a timing error check is performed648. During the timing error check648, the amount of motor current measured610and/or the amount of force determined632is continuously monitored for a pre-determined amount of time t. If the amount of current measured610for the one or more curves623remains below the characteristic amount of current determined for that given motor output shaft position within the one or more characteristic curves622after the time t, then the drop in current is likely due to the occurrence of the ball loss condition602and not simply a momentary drop in current due to control actions or measurement noise. This aids in reducing or eliminating false positive ball loss condition identifications which in turn aids in improving the overall life, durability and operational efficiency of the one or more clutch pack assemblies402of the drive unit assembly400.

Once the timing error check648has been performed, a flag is sent out650within the one or more control units540and/or the vehicle bus548switching the ball loss indicator from a “0” to a “1”. When the ball loss indicator has a “0” value, it indicates that a ball loss condition has not occurred within the one or more ball and ramp assemblies403of the drive unit assembly400. When the ball loss indicator has a “1” value, it is indicating that a potential ball loss has been detected within the one or more ball and ramp assemblies403of the drive unit assembly400. The one or more control units540and/or the vehicle bus548will then continuously monitor the duration or amount of time the ball loss indicator sends out a “1” value652. Additionally, the one or more control units540and/or the vehicle bus548will determine the number of times the ball loss indicator sends out a “1” value within a pre-determined amount of time652. If the duration of the “1” value or the number of “1” values exceeds a pre-determined amount, then the ball loss condition has been identified or determined602and the ball loss indicator will remain at a “1” value until the one or more balls490have been successfully recaptured. This final check aids in filtering out potential false positive potential ball loss flags that have been sent650that may have occurred due to control actions and measurement noise. This further aids in reducing or eliminating false positive ball loss condition identifications which in turn aids in improving the overall life, durability and operational efficiency of the one or more clutch pack assemblies402of the drive unit assembly400.

After the ball loss condition has been identified602, one or more ball recapture procedures654are run. As a non-limiting example, the one or more ball recapture procedures654run includes aligning the home position or pockets of the one or more first and second plate grooves501and503with each other. Once aligned, the one or more balls490will be able to return to their home position allowing for normal operation of the one or more ball and ramp assemblies403.

FIGS. 9 and 10illustrate a method of predicting when a ball loss condition will occur700in order to prevent the occurrence of the ball loss condition602within the one or more ball and ramp assemblies403of the drive unit assembly400. As illustrated inFIG. 9of the disclosure and as a non-limiting example, the method of predicting when a ball loss condition will occur700first includes a data gathering step702. As part of the data gathering step702, one or more actuation profiles704are run by the one or more motors506of the one or more clutch pack assemblies402of the drive unit assembly400. The one or more actuation profiles704of the method of predicting when a ball loss condition will occur700are defined as the total movement of the first and/or the second plate486and/or488of the one or more ball and ramp assemblies403from their home position (not shown) until they return back to their home position (not shown). In accordance with an embodiment of the disclosure and as a non-limiting example, the home position (not shown) for the first and second plates486and488is the position of the first and second plates486and488where the ball pockets701and703of the one or more first and second plate grooves501and503are aligned with one another. It is within the scope of this disclosure and as a non-limiting example that during the running of the one or more actuation profiles704, one or more cycles may be run by the one or more motors506to have the one or more ball and ramp assemblies403apply a variable amount of force onto the first and/or second plurality of clutch plates460and/or462.

While the one or more actuation profiles704are ran, the one or more first sensors538measure one or more pre-determined parameters or variables706. As illustrated inFIG. 9of the disclosure and as a non-limiting example, during the measuring of the one or more pre-determined parameters step706, the one or more first sensors538measure a position708of the motor output shaft510of the one or more motors506while the one or more actuation profiles704are being run. It is within the scope of this disclosure and as a non-limiting example that the one or more first sensors538may continuously or at pre-determined intervals measure the position708of the motor output shaft510of the one or more motors506throughout the one or more actuation profiles704ran. By measuring the position708of the motor output shaft510of the one or more motors506, the total distance traveled by the first and/or second plate486and/or488during the running of the one or more actuation profiles704can be determined.

Once the one or more pre-determined parameters or variables706are measured by the one or more first and second sensors538and544, the one or more pre-determined parameters or variables608are sent614to one or more data buffers616in the one or more control units540. The one or more data buffers616of the one or more control units540is a region of physical memory storage that is used to temporarily store the one or more pre-determined parameters or variables608during the data gathering step604while it is being transferred from one location to another within the one or more control units540and/or the vehicle bus548of the vehicle (not shown).

Once the one or more pre-determined parameters or variables706are measured by the one or more first sensors538, the one or more pre-determined parameters or variables706are sent710to the one or more data buffers616in the one or more control units540.

In accordance with the embodiment of the disclosure illustrated inFIG. 9and as a non-limiting example, the method of predicting when a ball loss condition will occur700may further include the step of averaging712the one or more pre-determined parameters or variables measured706by the one or more first sensors538. This will provide a mean value for the one or more pre-determined parameters measured706during the one or more actuation profiles704ran thereby providing an average profile for the one or more clutch pack assemblies402.

After the one or more pre-determined parameters or variables706have been measured, the motor output shaft position data708is received and analyzed by the one or more data processors546and/or552of the one or more control units540and/or the vehicle bus548. Once the motor output shaft position data measured708has been received by the one or more data processors546and/or552, the motor output shaft position data measured708is integrated for each of the one or more actuation profiles704run by the one or more ball and ramp assemblies403.

The method of predicting when a ball loss condition will occur700further includes the step of identifying a plurality of regions716within the one or more first plate grooves501in the first plate486of the one or more ball and ramp assemblies403. As best seen inFIG. 10of the disclosure and as a non-limiting example, the plurality of regions718within the one or more first plate grooves501of the first plate486are disposed along the length of the one or more first plate grooves501. Each of the plurality of regions718identified have an upper and a lower bound that define the entrance into one of the plurality of regions718and the exit from one of the plurality of regions718of the one or more first plate grooves501.

In accordance with an embodiment of the disclosure and as a non-limiting example, the plurality of regions718identified716represent different physical and pre-defined segments of the one or more first plate grooves501that are fixed based on the position of the motor output shaft510. According to an alternative embodiment of the disclosure and as a non-limiting example, the plurality of regions718identified716are not pre-defined segments that are fixed in terms of the position of the motor output shaft510needed to put the one or more balls490within that particular region of the plurality of regions718identified716. Instead, in accordance with this embodiment of the disclosure, the plurality of regions718identified716are dependent on the material tolerances, the temperature conditions of the drive unit assembly400, the amount of wear and tear on the various components within the drive unit assembly400, the materials of the components of the drive unit assembly400and/or the properties of the one or more motors506. As a result, it is to be understood that the plurality of regions718identified716may change for the one or more first plate grooves501over time or may be different from one drive unit assembly to another.

As illustrated inFIG. 9of the disclosure and as a non-limiting example, the method of predicting when a ball loss condition will occur700further includes the step of identifying a plurality of regions720within the one or more second plate grooves503in the second plate488of the one or more ball and ramp assemblies403. As best seen inFIG. 10of the disclosure and as a non-limiting example, the plurality of regions722within the one or more second plate grooves503of the second plate488are disposed along the length of the one or more second plate grooves503. Each of the plurality of regions722identified have an upper and a lower bound that define the entrance into one of the plurality of regions722and the exit from one of the plurality of regions722of the one or more second plate grooves503.

In accordance with an embodiment of the disclosure and as a non-limiting example, the plurality of regions722identified720represent different physical and pre-defined segments of the one or more second plate grooves503that are fixed based on the position of the motor output shaft510. According to an alternative embodiment of the disclosure and as a non-limiting example, the plurality of regions722identified720are not pre-defined segments that are fixed in terms of the position of the motor output shaft510needed to put the one or more balls490within that particular region of the plurality of regions722identified720. Instead, in accordance with this embodiment of the disclosure, the plurality of regions722identified720are dependent on the material tolerances, the temperature conditions of the drive unit assembly400, the amount of wear and tear on the various components within the drive unit assembly400, the materials of the components of the drive unit assembly400and/or the properties of the one or more motors506. As a result, it is to be understood that the plurality of regions722identified720may change for the one or more second plate grooves503over time or may be different from one drive unit assembly to another.

Once the plurality of regions718and722within the first and second plates486and488have been identified716and720, the amount of distance traveled by the one or more balls490within each of the plurality of regions718and722is determined724. It is within the scope of this disclosure and as a non-limiting example that the position of and therefore the distance traveled by the one or more balls490may be determined based on the position of the motor output shaft510measured708, the amount of force FBRapplied by the one or more ball and ramp assemblies403and/or the angle θ1of the first and/or second plate486and/or488. The amount of distance traveled724within each of the plurality of regions718and722identified716and720is not solely dependent on the entering and exiting of a given region. Each and every change in the direction of the one or more balls490within each of the plurality of regions718and722identified716and720is counted toward the total distance traveled determined724in this step.

After the amount of distance traveled within each of the plurality of regions718and722has been determined724, one or more weight factors are then applied726to the amount of distance traveled within each of the plurality of regions718and722identified716and720in the one or more first and second grooves501and503of the first and second plates486and488. The weight factor applied to each of the plurality of regions718and722identified716and720is dependent on the amount of force FBRthat the one or more ball and ramp assemblies403will apply onto the first and/or second plurality of clutch plates460and/or462within that particular region identified716and720. It is to be understood that the higher position of the motor output shaft510measured708, the further the one or more balls490are disposed along the length of the incline of the one or more first and second plate grooves501and503and the greater the amount of force FBRapplied by the one or more ball and ramp assemblies403onto the first and/or second plurality of clutch plated460and/or462.

In accordance with an embodiment of the disclosure and as a non-limiting example, the regions of the plurality of regions718and722identified716and720corresponding to a greater amount of force FBRbeing exerted onto the first and/or second plurality of clutch plates460and/or462have a lesser amount of influence one the occurrence of a ball loss condition and are thus weighted less. The regions of the plurality of regions718and722identified716and720corresponding to a lower amount of force FBRbeing exerted onto the first and/or second plurality of clutch plates460and/or462have a greater amount of influence one the occurrence of a ball loss condition and are thus weighted more. As a result, it is to be understood that the weighted average applied to each region of the plurality of regions718and722identified716and720reduces as the one or more balls490travel up the incline of the one or more first and second plate grooves501and503of the first and second plates586and488. In the same way, the weighted average applied to each region of the plurality of regions718and722identified716and720increases as the one or more balls490travel down the incline of the one or more first and second plate grooves501and503of the first and second plates586and488. It is therefore to be understood that the greater the amount of distance traveled determined724, within the low force FBRregions of the one or more first and second grooves501and503, the greater the impact on the method of predicting when a ball loss condition will occur700.

As illustrated inFIG. 9of the disclosure and as a non-limiting example, the method of predicting when a ball loss condition will occur700further includes the step of continuously accumulating and/or monitoring the total distance traveled by the one or more balls490within each region of the plurality of regions718and722identified716and720in a weighted manner for each of the one or more actuation profiles run704. These accumulated amount of weighted distanced traveled determined728are then compared to a pre-determined threshold value730. It is within the scope of this disclosure and as a non-limiting example that the pre-determined threshold value730represents a limit for the total amount of travel by the one or more balls490of the one or more ball and ramp assemblies403within a given actuation profile run704.

The accumulated amount of weighted distanced traveled determined728compared to a pre-determined threshold value730is then scaled to a pre-determined range732. In accordance with an embodiment of the disclosure and as a non-limiting example, the pre-determined range732may be from approximately 0 to approximately 100 which can be seen as a percentage of approximately 0% to approximately 100%. The closer the accumulated amount of weighted distanced traveled determined728is to the pre-determined threshold value730, the higher the scaling732. The further the accumulated amount of weighted distanced traveled determined728is from the pre-determined threshold value730, the lower the scaling732. In accordance with an embodiment of the disclosure and as a non-limiting example, any accumulated amount of weighted distanced traveled728that is determined to be scaled732over 100%, will not be accumulated728, weighted726or sent out for analysis by the one or more data processors546and/or552.

Once the accumulated amount of weighted distanced traveled determined728has been compared to a pre-determined threshold value730and scaled to the pre-determined range732, the step of predicting whether or not a ball loss condition will occur734is performed. If the scaled to a pre-determined range determined732is low, for example from approximately 0% to approximately 30%, then the likelihood of the occurrence of a ball loss condition is low and a ball loss condition indicator value “1” is not triggered. If however, the scaled to a pre-determined range determined732is high, for example from approximately 80% to approximately 100%, then the likelihood of the occurrence of a ball loss condition is high and a ball loss condition indicator value “1” is triggered.

When the method of predicting when a ball loss condition700described herein has predicted734that the occurrence of a ball loss condition is high and the ball loss indicator valve “1” has been triggered, one or more ball recapture procedures are run736. As a non-limiting example, the one or more ball recapture procedures736run includes aligning the home position or pockets701and703of the one or more first and second plate grooves501and503with each other. Once aligned, the one or more balls490will be able to return to their home position allowing for normal operation of the one or more ball and ramp assemblies403. Upon successful completion of the ball recapture736, the ball loss indicator value is set back to “0”, the accumulated amount of weighted distanced traveled determined728are set back to zero and the method of predicting when a ball loss condition700is started over again. As a result, the method of predicting when a ball loss condition700described herein allows the one or more ball and ramp assemblies403to prevent a ball loss condition from occurring. This aids in increasing the overall operational efficiency of the drive unit assembly400by reducing or eliminating the number of ball loss conditions that occur within the one or more ball and ramp assemblies403when in operation. Additionally, this aids in increasing the overall accuracy and duration of the amount of force that is applied by the one or more ball and ramp assemblies403onto the first and/or second plurality of clutch plates486and/or488by reducing or eliminating the number of ball loss conditions thereby improving the overall operation of the drive unit assembly400.

It is within the scope of this disclosure that the various embodiments of the disclosure described and illustrated herein may be combined with one another to make a method of determining the occurrence of a ball loss condition and/or a method of predicting when a ball loss condition will occur according to an embodiment of the disclosure. Additionally, it is within the scope of this disclosure that the various embodiments of the drive unit assembly described herein may be combined to provide a drive unit assembly incorporating the use of a ball loss condition and/or a method of predicting when a ball loss condition will occur according to an embodiment of the disclosure.

In accordance with the provisions of the patent statutes, the present invention has been described to represent what is considered to represent the preferred embodiments. However, it should be noted that this invention can be practiced in other ways than those specifically illustrated and described without departing from the spirit or scope of this invention.