Patent ID: 12253149

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Various aspects of the disclosure will hereinafter be described in conjunction with the appended drawings to illustrate and not to limit the disclosure, wherein like designations denote like elements, and variations of the described aspects are not restricted to the specifically shown embodiments, but are applicable on other variations of the disclosure.

FIGS.1,2A-2B, and3A-3Cschematically show a differential gear unit1for a vehicle according to a first embodiment, andFIGS.4,5A-5B, and6A-6Cschematically show a differential gear unit1for a vehicle according to an alternative embodiment. The differential gear unit1of the respective illustrated embodiments comprise an annular ring gear2arranged to rotate around a rotational axis A extending in an axial direction DA. The ring gear2comprises an external surface2c, and a hub structure2awith an internal surface2b. The external surface2cis arranged as a toothed surface for driving engagement with a non-illustrated rotating input drive shaft, where the toothed surface of the ring gear2is meshing with a toothed surface of for example an input drive shaft pinion gear. In alternative non-illustrated embodiments, the toothed surface may instead be arranged on other parts of the ring gear2.

The differential gear unit1of the illustrated embodiments further comprises side gears and differential pinion gears of the bevel gear type. A first side gear3ais configured for distributing a first output torque TO1to a first drive shaft S1, and a second side gear3bis configured for distributing a second output torque TO2to a second drive shaft S2. The first side gear3aand the second side gear3bare arranged on opposite sides of the ring gear2in the axial direction DA. At least a first differential pinion gear4aand a second differential pinion gear4bare configured for engaging the first side gear3aand the second side gear3b, and in the embodiments illustrated inFIGS.1,2A-2B,3A-3C,4,5A-5B, and6A-6C, the differential gear unit1comprises two differential pinion gears. However, the differential gear unit1may instead be arranged with three or more differential pinion gears. The differential pinion gears are as illustrated in the figures in a conventional manner arranged with toothed surfaces that are engaging toothed surfaces of the side gears. The first differential pinion gear4aand the second differential pinion gear4bare rotatably arranged on a pinion pin5, and the differential pinion gears are configured for transferring torque from the ring gear2to the side gears.

The differential gear unit1further comprises a decoupling element6arranged radially inside the ring gear2, as illustrated in for exampleFIGS.3A-3C and6A-6C. The decoupling element6is rotatably arranged in relation to the ring gear2, and the pinion pin5is connected to and extending diametrically across the decoupling element6. The decoupling element6has in the illustrated embodiments a collar-like configuration. The decoupling element6is at least partly arranged radially inside the hub structure2aof the ring gear2, and an outer surface6aof the decoupling element6is rotatably arranged in relation to the internal surface2bof the ring gear2. One or more inner bearings14may be arranged between the outer surface6aof the decoupling element6and the internal surface2bof the ring gear2, as schematically illustrated in for exampleFIGS.1and4. The pinion pin5is depending on operational states of the differential gear unit1arranged for transferring torque from the ring gear2to the respective differential pinion gears, as will be further described below. Upon rotation of the ring gear2by for example the input drive shaft pinion gear, the pinion pin5could through the attachment to the decoupling element6, and the arrangement of the decoupling element6in relation to the ring gear2, be arranged to rotate with the ring gear2, depending on the operational state of the differential gear unit1. The rotational movement of the pinion pin5with the ring gear2via the decoupling element6is used for transferring the torque to the first side gear3aand the second side gear3bvia the first differential pinion gear4aand the second differential pinion gear4b. With the configuration of the differential gear unit1, the side gears and the differential pinion gears are positioned radially inside the ring gear2, as indicated in for exampleFIGS.2A-2B and5A-5B. The pinion pin5is thus configured for transferring an input torque T1from the ring gear2to the side gears via the differential pinion gears.

The decoupling element6comprises diametrically opposite openings6cfor holding the pinion pin5in position relative to the decoupling element6. With this arrangement, the pinion pin5is positioned diametrically across the decoupling element6, as understood from for exampleFIGS.1,2A-2B,4and5A-5B. Instead of the openings6c, the decoupling element6may be arranged with slots or similar arrangements for holding the pinion pin5.

The differential gear unit1further comprises a clutch sleeve7slidably arranged relative to the ring gear2and the decoupling element6in the axial direction DA. With this configuration, the clutch sleeve7is allowed to slide axially in different operational positions in relation to the ring gear2and the decoupling element6. Upon displacement in the axial direction DA, the clutch sleeve7is configured for being positioned in a first axial position PA1, a second axial position PA2, and a third axial position PA3. In the embodiments illustrated inFIGS.1,2A-2B,3A-3C,4,5A-5B, and6A-6C, the clutch sleeve7has a collar-like configuration. It should however be understood that the clutch sleeve7may have other suitable shapes and configurations. The differential gear unit1further comprises an actuating unit9in engagement with the clutch sleeve7. The actuating unit9is used for displacing the clutch sleeve7relative to the ring gear2and the decoupling element6in the axial direction DA, and the actuating unit9is suitably connected to a control unit13for operating the differential gear unit9into the different axial positions, as schematically shown inFIGS.3A-3C and6A-6C. The actuating unit9may be of any suitable type, such as for example a linear actuator, a solenoid, or an electric motor.

Different axial positions of the clutch sleeve are schematically illustrated inFIGS.3A-3C and6A-6C. In a first axial position PA1, as illustrated inFIGS.3A and6A, the ring gear2is disconnected from the decoupling element6, and in the first axial position PA1rotational movement of the decoupling element6relative to the ring gear2is allowed. In a second axial position PA2, as illustrated inFIGS.3B and6B, the ring gear2is connected to the decoupling element6, and in the second axial position PA2rotational movement of the decoupling element6relative to the ring gear2is prevented. In a third axial position PA3, as illustrated inFIGS.3C and6C, the ring gear2is connected to a park-lock structure8, and in the third axial position PA3, the ring gear is prevented from rotating relative to the park-lock structure8.

In the embodiments illustrated inFIGS.3C and6C, the clutch sleeve7is in the third axial position PA3not only configured for connecting the ring gear2to the park-lock structure8, but also configured for simultaneously connecting the ring gear2to the decoupling element6. This configuration prevents rotational movement of the decoupling element6relative to the ring gear2, and rotational movement of the ring gear2relative to the park-lock structure8. Thus, both the decoupling element6and the ring gear2are prevented from rotating relative to the park-lock structure8for an efficient park-locking function, where the wheels of the vehicle are prevented from rotating.

The clutch sleeve7comprises a sleeve body7awith a first toothed surface7b, as shown in for exampleFIGS.1and4. The clutch sleeve7has in the illustrated embodiments a collar-like configuration and the sleeve body7ais arranged radially outside the hub structure2a, as understood fromFIGS.3A-3C and6A-6C. The first toothed surface7bis arranged on a radially inner surface7dof the sleeve body7a.

The hub structure2acomprises one or more grooves10extending in the axial direction DA. The one or more grooves10are configured for receiving one or more radially protruding tooth elements11of the first toothed surface7b. As understood fromFIGS.3A-3Cand6A-6C, the radially protruding tooth elements11are through engagement with the grooves10configured for preventing rotational movement of the clutch sleeve7relative the hub structure2a. The decoupling element6comprises a radially outer toothed surface6bwith one or more radially protruding tooth elements15, as shown in for exampleFIGS.1and4. The one or more radially protruding tooth elements11of the first toothed surface7bare further configured for engaging the one or more radially protruding tooth elements15of the radially outer toothed surface6bin the second axial position PA2and third axial position PA3. The decoupling element6may be provided with a track, a groove, or similar arrangement for the tooth elements11of the first toothed surface7b, preventing the tooth elements11from engaging the decoupling element6in the first axial position PA1, allowing the decoupling element6to rotate relative to the ring gear2.

The radially outer toothed surface6band the first toothed surface7bare disengaged from each other in the first axial position PA1, as shown inFIGS.3A and6A. When the radially outer toothed surface6band the first toothed surface7bare disengaged from each other in the first axial position PA1, the decoupling element6is free to rotate relative to the ring gear2and torque is prevented from being transferred from the ring gear2to the differential pinion gears via the decoupling element6. The radially outer toothed surface6band the first toothed surface7bare in engagement with each other in the second axial position PA2and in the third axial position PA3via the radially protruding tooth elements11of the first toothed surface7band the radially protruding tooth elements15of the radially outer toothed surface6b, as shown inFIGS.3B-3C and6B-6C. When the radially outer toothed surface6band the first toothed surface7bare in engagement with each other in the second and third axial positions, the rotational movement of the decoupling element6relative to the ring gear2is prevented and torque can be transferred from the ring gear2to the differential pinion gears and the side gears via the decoupling element6.

The sleeve body7afurther comprises a second toothed surface7cwith one or more protruding tooth elements16, as shown in for exampleFIGS.1and4. The second toothed surface7cis arranged on a radially outer surface7eof the sleeve body7a. The park-lock structure8comprises a toothed area8awith one or more protruding tooth elements17, as shown in for exampleFIGS.1and4. The second toothed surface7cand the toothed area8aare disengaged from each other in the first axial position PA1and in the second axial position PA2, as shown inFIGS.3A-3B and6A-6B. When the second toothed surface7cand the toothed area8are disengaged from each other in the first and second axial positions, the ring gear2is free to rotate relative to the park-lock structure8and in these axial positions, the park-lock function is deactivated. The second toothed surface7cand the toothed area8are in engagement with each other in the third axial position PA3, as shown inFIGS.3C and6C. When the second toothed surface7cand the toothed area8are in engagement with each other in the third axial position PA3, the ring gear2is prevented from rotating relative to the park-lock structure8and in this axial position, the park-lock function is activated.

As understood fromFIGS.3A-3C and6A-6C, the one or more protruding tooth elements16of the second toothed surface7care configured for engaging the one or more protruding tooth elements17of the toothed area8ain the third axial position PA3.

In the embodiment illustrated inFIGS.1,2A-2B, and3A-3C, the park-lock structure8has a ring-like configuration. The park-lock structure8is arranged radially outside the hub structure2a, as shown in for exampleFIGS.3A-3C. In the embodiment illustrated inFIGS.4,5A-5B, and6A-6C, the park-lock structure8has an arc-like configuration. The park-lock structure8is arranged radially outside the hub structure2a, as shown in for exampleFIGS.6A-6C. The park-lock structure8is suitably connected to a differential housing12, or similar structure of a vehicle drivetrain. It should however be understood that the park lock structure8may have any suitable shape, design, and configuration for engaging the clutch sleeve7.

The side gears3a,3band the at least first differential pinion gear4aand second differential pinion gear4bare positioned radially inside the decoupling element6, as shown inFIGS.2A-2B,3A-3C,5A-5B, and6A-6C. The decoupling element6is via the at least first differential pinion gear4aand second differential pinion gear4bconfigured for transferring input torque T1from the ring gear2to the first side gear3aand second side gear3b.

As described above, the actuating unit9is in engagement with the clutch sleeve7and suitably controlled with the control unit13. The actuating unit9is adapted for displacing the clutch sleeve7relative to the ring gear2and the decoupling element6, in the axial direction DA, between the first axial position PA1, the second axial position PA2, and the third axial position PA3.

As shown in for exampleFIGS.1and4, the differential gear unit1further comprises a first bearing flange18aarranged in connection to a first side of the ring gear2, and a second bearing flange18barranged in connection to a second side of the ring gear2. The first bearing flange18a, the second bearing flange18b, are configured for at least partly enclosing the first side gear3a, the second side gear3b, the first differential pinion gear4a, and the second differential pinion gear4b. The bearing flanges are arranged as cover structures for keeping lubrication in place and for holding bearings. The first bearing flange18aand the second bearing flange18bmay have any suitable configuration, and each bearing flange may be provided with one or more seals in connection to its corresponding side gear. The first bearing flange18aand the second bearing flange18bare suitably symmetrical in shape for a cost efficient and simple construction of the differential gear unit1. As shown inFIG.1, the first bearing flange18ais arranged with a first bearing surface19afor holding a first bearing20a. The second bearing flange18bis arranged with a second bearing surface19bfor holding a second bearing20b. Each of the first bearing flange18aand the second bearing flange18bis suitably connected to the ring gear2with one or more welds or other fastening means.

To operate the differential gear unit1, the actuating unit9is displacing the clutch sleeve7relative to the ring gear2and the decoupling element6, in the axial direction DA, between the first axial position Pal, the second axial position PA2, and the third axial position PA3. The different axial positions may be operated in any sequence, depending on the driving conditions of the vehicle.

By displacing the clutch sleeve7of the illustrated embodiments in the axial direction DA to the first axial position Pal, the ring gear2is disconnected from the decoupling element6, as illustrated inFIGS.3A and6A. The first axial position PA1is reached from the second axial position PA2, or from the third axial position PA3via the second axial position PA2, as understood fromFIGS.3A-3C and6A-6C. In the first axial position Pal, rotational movement of the decoupling element6relative to the ring gear2is allowed, and thus no torque is transferred from the ring gear2to the differential pinion gears and the side gears due to the non-engagement of the radially protruding tooth elements11of the clutch sleeve7and the radially protruding tooth elements15of the decoupling element6. The first axial position PA1is used during driving of the vehicle when there is no need to transfer torque from a propulsion unit, such as an internal combustion engine and/or an electric motor, to the wheels of the vehicle, for example when the vehicle is allowed to roll without any torque transfer.

By displacing the clutch sleeve7of the illustrated embodiments in the axial direction DA to the second axial position PA2, the ring gear2is connected to the decoupling element6, as illustrated inFIGS.3B and6B. The second axial position PA2is reached from the first axial position Pal, or from the third axial position PA3, as understood fromFIGS.3A-3C and6A-6C. In the second axial position PA2, rotational movement of the decoupling element6relative to the ring gear2is prevented, and thus torque is transferred from the ring gear2to the differential pinion gears and the side gears due to the engagement of the radially protruding tooth elements11of the clutch sleeve7with the radially protruding tooth elements15of the decoupling element6. The second axial position PA2is used during driving of the vehicle when there is a need to transfer torque from the propulsion unit to the wheels of the vehicle.

By displacing the clutch sleeve7of the illustrated embodiments in the axial direction DA to the third axial position PA3, the ring gear2is connected both to the decoupling element6and to the park-lock structure8, as illustrated inFIGS.3C and6C. The third axial position PA3is reached from the second axial position PA2, or from the first axial position PA1via the second axial position PA2, as understood fromFIGS.3A-3C and6A-6C. In the third axial position PA3, rotational movement of the decoupling element6relative to the ring gear2is prevented, and rotational movement of the ring gear2relative to the park-lock structure is prevented. Thus, the park-lock functionality is enabled through the engagement of the radially protruding tooth elements11of the clutch sleeve7with the radially protruding tooth elements15of the decoupling element6, in combination with the engagement of the protruding tooth elements16of the clutch sleeve7with the protruding tooth elements17of the park-lock structure8. In the third axial position PA3, the ring gear2is connected to both the park-lock structure8and the decoupling element6for preventing rotational movement of the decoupling element6relative to the ring gear2and rotational movement of the ring gear2relative to the park-lock structure8. The decoupling element6and the ring gear2are prevented from rotating relative to the park-lock structure8for an efficient park-locking function. The third axial position PA3is used during non-driving of the vehicle when there is a need to prevent the vehicle from rolling, such as when the vehicle is parked.

It will be appreciated that the above description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure as defined in the claims. Furthermore, modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims. Reference signs mentioned in the claims should not be seen as limiting the extent of the matter protected by the claims, and their sole function is to make claims easier to understand.

REFERENCE SIGNS

1: Differential gear unit2: Ring gear2a: Hub structure2b: Internal surface2c: External surface3a: First side gear3b: Second side gear4a: First differential pinion gear4b: Second differential pinion gear5: Pinion pin6: Decoupling element6a: Outer surface6b: Outer toothed surface6c: Opening7: Clutch sleeve7a: Sleeve body7b: First toothed surface7c: Second toothed surface7d: Radially inner surface7e: Radially outer surface8: Park-lock structure8a: Toothed area9: Actuating unit10: Groove11: Tooth elements, First toothed surface12: Differential housing13: Control unit14: Inner bearing15: Tooth elements, Outer toothed surface16: Tooth elements, Second toothed surface17: Tooth elements, Toothed area18a: First bearing flange18b: Second bearing flange19a: First bearing surface19b: Second bearing surface20aFirst bearing20bSecond bearingDA: Axial directionPA1: First axial positionPA2: Second axial positionPA3: Third axial positionS1: First drive shaftS2: Second drive shaftT1: Input torqueTO1: First output torqueTO2: Second output torque