Patent Description:
All electric, hybrid electric, and plug-in hybrid electric vehicles (collectively referred to as EVs) have a powertrain to transfer power from various power generators to the driven wheels of the vehicle. Traditional transmissions utilize hydraulics and friction to operate. These two performance principles work well in the traditional transmission when powered by an internal combustion engine. The physics of these traditional transmission result in extreme amounts of energy waste, preventing their incorporation into EVs due to the limitations on range these losses create. <CIT> discloses a powertrain for a hybrid vehicle. While the powertrain utilizes a transmission that incorporates input torques from three different sources (an internal combustion engine and two motors), the transmission is incapable of performing such actions as hill-hold and park because it incorporates traditional hydraulically activated friction clutches.

According to the invention, this object is solved by the combination of features of claim <NUM>. The dependent claims show further advantageous embodiments of the invention.

Advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:.

For purposes of this discussion, elements will be identified by reference characters, typically reference numerals. There are several embodiments shown in the Figures that will be described in detail below. For purposes of simplicity, these elements will retain their reference characters throughout the discussion. If an element has characteristics that are different from one embodiment to another, those differences will be discussed when introducing the same element for the new embodiment.

Referring to <FIG>, a perspective view of one embodiment of a transmission is generally shown at <NUM>. In this Figure, the transmission <NUM> is operatively connected to a first motor <NUM> and a second motor <NUM>. Physically, the second motor <NUM> is mounted to the transmission <NUM> between the transmission <NUM> and the first motor <NUM>. The first motor <NUM> has an output (discussed subsequently) that extends through the second motor <NUM> and to the transmission <NUM>.

The transmission <NUM> includes a transmission housing <NUM> having a housing cap <NUM>. <FIG> and <FIG> show the second motor <NUM> (B-Motor) secured to the transmission housing <NUM> and the first motor <NUM> (A-Motor) secured to the second motor <NUM> (B-Motor). A first motor output shaft <NUM> of the first motor <NUM> (A-Motor) defines a length <NUM> that is longer than a length <NUM> of the first motor <NUM>. The first motor output shaft <NUM> also defines an outer diameter <NUM> at its distal end <NUM>.

The second motor <NUM> (B-Motor) includes a second motor output shaft <NUM>. The second motor output shaft <NUM> defines an inner diameter <NUM> that is larger than the outer diameter <NUM> of the first motor output shaft <NUM>. The first motor output shaft <NUM> extends through and is coaxial with the second motor output shaft <NUM>. It should be appreciated by those skilled in the art that the first motor output shaft <NUM> may not extend all the way through the second motor output shaft <NUM>.

In alternative embodiments that will be discussed in greater detail below, the first <NUM> and second <NUM> motors may be mounted on either side of the transmission <NUM>. Oil used to cool the transmission <NUM>, the first motor <NUM> and the second motor <NUM> is collected by a catch basin <NUM> and recirculated using a sump <NUM>. Because the catch basin <NUM> extends along the entire length of the transmission <NUM>, the first motor <NUM> and the second motor <NUM>, only one sump <NUM> is necessary. The transmission <NUM> has an output shaft <NUM> that extends out through the center of the housing cap <NUM>. Electrical ports <NUM> provide electrical access (power and communications) inside the first <NUM> and second <NUM> motors. The transmission <NUM>, first motor <NUM>, second motor <NUM>, and sump <NUM> may be referred to as a powertrain, generally shown at <NUM>.

Referring to <FIG>, the powertrain <NUM> is shown mounted between two rails <NUM>, <NUM> of a vehicular frame, generally shown at <NUM>. A body <NUM>, including a passenger compartment (not shown), is shown fixedly secured to the vehicular frame <NUM>. Referring specifically to <FIG>, the transmission <NUM> is shown connected to a drive line <NUM> that drives four wheels (none shown).

Referring to <FIG>, the transmission <NUM> is shown in a configuration for operating with a single input. In this configuration, which is not a part of the present invention, the single input is the first motor <NUM> fixedly secured directly to the transmission housing <NUM> in the absence of the second motor <NUM>. The first motor <NUM> is not shown in <FIG>, but the first motor output shaft <NUM> would be received by the input shaft <NUM>.

The input shaft <NUM> is also designated as shaft "<NUM>" in the power flow shown in <FIG>. The transmission <NUM> also includes a first gearset, generally shown at <NUM>, and a second gearset, generally shown at <NUM>. The first gearset <NUM> includes first <NUM>, second <NUM> and third <NUM> rotating members. The second gearset <NUM> includes a fourth <NUM>, fifth <NUM>, and sixth <NUM> rotating members. These gearsets <NUM>, <NUM> may be any gearset that has three rotating members. Types of gearsets contemplated include, but are not limited to, Ravigneaux gearsets, Simpson gearsets and ring-carrier/ring-carrier gearsets. The gearsets <NUM>, <NUM> shown in <FIG> and <FIG> are ring-carrier/ring-carrier gearsets. Because these gearsets are ring-carrier/ring-carrier gearsets, the first, second and third rotating members are a sun gear, a carrier and a ring gear, respectively. These are indicated as S1, C1, and R1 for the first gearset <NUM> and S2, C2, and R2 for the second gearset <NUM>. Two rotating members from the first gearset <NUM> and two rotating members from the second gearset <NUM> are fixedly secured to each other. These connections create a four-node linkage for the transmission <NUM>. As such, each pair of rotating members is represented by a single circle in <FIG>. Therefore, the third rotating member <NUM> (ring gear R1) and the fifth rotating member <NUM> (carrier C2) are fixedly secured to each other and represented by both reference numerals <NUM> and <NUM> in <FIG>, whereas the second rotating member <NUM> (carrier C1) and the sixth rotating member <NUM> (ring gear R2) are fixedly secured to each other and represented by both reference numerals <NUM> and <NUM> in <FIG>.

The output shaft <NUM> of the transmission <NUM> is also fixedly secured to two rotating members, one from each gearset <NUM>, <NUM>. In the first example embodiment shown in <FIG> and <FIG>, the output shaft <NUM> is fixedly secured to the third rotating member <NUM> (the ring gear R1of the first gearset <NUM> and the fifth rotating member <NUM> of the second gearset <NUM> (the carrier C2 of the second gearset <NUM>). The motor <NUM> is connected directly to the fourth rotating member <NUM> of the second gearset <NUM> using the input shaft <NUM> (shaft <NUM>).

A controllable clutch <NUM> is connected between the input shaft <NUM> (shaft <NUM>) at one end and the output shaft <NUM> (shaft <NUM>) at the other end. The controllable clutch <NUM> is also represented by the nomenclature K13 because it couples shafts <NUM> and <NUM> together. Referring specifically to <FIG>, the controllable clutch <NUM> is represented by a switch <NUM> and two diodes <NUM>, <NUM>. These three elements <NUM>, <NUM>, <NUM> represent the attributes of the controllable clutch <NUM>. More specifically, the switch <NUM> signifies that the controllable clutch <NUM> may be turned on and off. The diodes <NUM>, <NUM> represent the fact that the controllable clutch <NUM> may either bidirectionally lock the third rotating member <NUM> (ring gear R1), the fifth rotating member <NUM> (second carrier C2) and the output shaft <NUM> (shaft <NUM>), or allow those elements <NUM>, <NUM>, <NUM> to rotate freely in both directions. Therefore, when the switch <NUM> is closed, representing the active state for the controllable clutch <NUM>, the output shaft <NUM> rotates with the rotation of the input shaft <NUM>. When the switch <NUM> is open, representing an inactive state for the controllable clutch <NUM>, the output shaft <NUM> does not rotate or, alternatively, rotates based on the torques it receives from the other rotating elements <NUM>, <NUM>, <NUM>, <NUM> of the first <NUM> and second <NUM> gearsets.

The transmission <NUM> also includes a first controllable brake <NUM> (B04) that couples the first rotating member <NUM> (sun gear S1) of the first gearset <NUM> to the transmission housing <NUM>. The first controllable brake <NUM> also has the symbol B04 because it is a brake that connects shaft <NUM> (which is just the transmission housing <NUM>) with a fourth shaft <NUM> (shaft <NUM>). The first controllable brake <NUM> (B04) is similar to the controllable clutch <NUM> in that it is represented by two diodes <NUM>, <NUM> representing that it will lock and allow rotation in either direction. The first controllable brake <NUM> (B04) is different from the controllable clutch <NUM> in that each direction of operation can be controlled independently of the other, as represented by switches <NUM>, <NUM>. Operation of the first controllable brake <NUM> will be discussed in greater detail subsequently.

This transmission <NUM> also includes a second controllable brake <NUM> which couples the second rotating member <NUM> (carrier C1) of the first gearset <NUM> and the sixth rotating member <NUM> (ring R2) of the second gearset <NUM> to the transmission housing <NUM>. The second controllable brake <NUM> differs from the first controllable brake <NUM> in that it only has the ability to control whether a notch plate <NUM> (shaft <NUM>) is rotating or if it is tied to the transmission housing <NUM> and prevented from rotating. As such, the second controllable brake <NUM> only includes a single switch <NUM> representing the two states of the second controllable clutch <NUM> (B05) as being either on or off, and two diodes <NUM>, <NUM> indicate that the second controllable brake <NUM> (B05) can lock or allow the notch plate <NUM> (shaft <NUM>) rotate in either direction.

<FIG> also includes two levers <NUM>, <NUM>. These levers <NUM>, <NUM> are graphic representations of how torques received by the transmission <NUM> affect the torque provided at the output shaft <NUM> (shaft <NUM>). The first lever <NUM> represents when no speed is applied to the output shaft <NUM> (shaft <NUM>) and/or when the transmission <NUM> is at rest. The second lever <NUM> represents a transmission <NUM> in a state of operation that will be discussed in greater detail subsequently.

Referring to <FIG>, the transmission <NUM> is shown with the motor <NUM> secured transverse to a driven axle <NUM>. The torque at the output shaft <NUM> (not shown in <FIG>) is redirected using a gearset <NUM> that connects the output shaft <NUM> to an axle differential <NUM>. As is well known in the art, the axle <NUM> drives wheels <NUM> and tires <NUM>.

Referring to <FIG>, an embodiment of the transmission <NUM> according to the invention is shown attached transversely to an axle differential <NUM> via the gearset <NUM> in a manner similar to that which was shown in the first embodiment in <FIG>. The difference between this transmission <NUM> in the transmission of the prior Figure is that this transmission <NUM> receives two inputs, one from the first motor <NUM> (A-Motor) and one from a second motor <NUM> (B-Motor). It may be appreciated by those skilled in the art that the transmission <NUM> with inputs from a first motor <NUM> (A-Motor) and a second motor <NUM> (B-Motor) will provide a wider range of torque at the output shaft <NUM>.

Referring to <FIG>, a third configuration for the transmission <NUM> is shown wherein the transmission <NUM> receives inputs from the first motor <NUM> (A-Motor) and the second motor <NUM> (B-Motor). The gearset <NUM> used to direct the torques provided by the output shaft <NUM> is mirrored so that the torques provided by the output shaft <NUM> may be directed in two directions to drive two axle differentials <NUM> to, in turn, drive the driven axles <NUM>.

Referring to <FIG>, the third configuration of the transmission <NUM> is shown with an example gearset <NUM> shown directing output torque in two different directions to drive the two axles <NUM>. This gearset <NUM> is shown to be in line with the output shaft <NUM>, the transmission <NUM> and the motors <NUM>, <NUM>. Different configurations may be employed depending on the needs and the design parameters for such a system. It should be appreciated by those skilled in the art that other alignments may be used to, for instance, facilitate collection of lubricating fluids. Not shown is a housing that covers the gearset <NUM> - such a housing should be well known to those skilled in the art.

Referring to <FIG>, the cross-sectional side view illustrates the two-input configuration of the transmission <NUM> shown in <FIG> and discussed above (as stated above, elements discussed above will retain the same reference characters in this and any subsequent embodiment). In this embodiment, the input shaft <NUM> becomes the first input shaft <NUM>. While the first input shaft <NUM> is identical to the input shaft <NUM> in the one-input embodiment discussed above, a coupling end <NUM> of the first input shaft <NUM> has the same outer diameter and a much larger inner diameter. In other words, the coupling end <NUM> of the first input shaft <NUM> is thinner than that of the input shaft <NUM> in the one-input example embodiment shown in <FIG>.

A second input shaft is a pocket plate <NUM>. The second input shaft <NUM> is coaxial with the first input shaft <NUM>. The second input shaft <NUM> receives torque from the second motor output shaft <NUM>, whereas the coupling end <NUM> of the first input shaft <NUM> receives torque from a first motor output shaft <NUM> of the first motor <NUM>. The first <NUM> (A-Motor) and second <NUM> (B-Motor) motors provide independent inputs into the transmission <NUM> to provide multiple modes of operation for the overall powertrain. The inputs of the first <NUM> and second <NUM> motors are torques that are transferred to the transmission <NUM> through the first <NUM> and second <NUM> input shafts.

Both first <NUM> and second <NUM> input motors are electric. These motors <NUM>, <NUM> operate independently of each other and in concert with each other, depending on the mode in which the powertrain <NUM> is operating. In the power flow Figures that follow, the first input motor <NUM> and the second input motor <NUM> are designated as "A-Motor" and "B-Motor," respectively.

Referring to <FIG>, the transmission <NUM>, which is not a part of the present invention, is shown to be operating from launch through mid-range vehicle speeds (<NUM>-<NUM> MPH). A low one-way clutch <NUM>, represented by a diode is used to ground/lock (transmission housing <NUM>) the second rotating member <NUM> (carrier C1) and the sixth rotating member <NUM> (ring gear R2). Another clutch <NUM> is switchable via switch <NUM> to allow the second rotating member <NUM> (carrier C1) and the sixth rotating member <NUM> (ring gear R2) to rotate.

At these speeds, the transmission <NUM> is in Speed Ratio Mode (SRM). A lever <NUM> represents the output in SRM. In SRM, the speeds of the first <NUM> and second <NUM> motors are a fixed ratio relative to output speed. The first motor <NUM> has a ratio A to output and the second motor <NUM> has a ratio B to output. So, in SRM for a given vehicle speed, the speed of the motors <NUM>, <NUM> are fixed relative to their corresponding ratios. This is best seen in <FIG>, where the vertical line represents a particular speed at which the first <NUM> and second <NUM> motors are operating. The goal is to provide the proper torque output at that speed to maximize the efficiency of the motors <NUM>, <NUM>. As can be seen in <FIG>, the center portions of the shaded graphed area are the ranges in which the motors <NUM>, <NUM> are most efficient.

In SRM, the first motor <NUM> can be powered independently of second motor <NUM>. The three operating states of the powertrain <NUM> in SRM include power the first motor <NUM> only; power the second motor <NUM> only; and power the two motors <NUM>, <NUM> together at the same time.

While the speed of the motors <NUM>, <NUM> relative to output is fixed via a ratio, the torques in each motor <NUM>, <NUM> can vary from zero to maximum torque. The output torque is determined by this following formula
<MAT>
where:.

The variables X, Y, and Z are determined by the sun and ring gear tooth counts in a ring-carrier/ring-carrier gearset. The variables are the same for all gearsets that can be defined by a four-node relationship. How X, Y and Z are calculated is dependent on the type of four-node lever relationship employed.

<FIG> illustrates a lever diagram showing the transmission <NUM> of <FIG> in transition from a speed ratio mode (as shown in <FIG>) into a torque ratio mode. Again, the lever <NUM> represents the output in SRM, whereas the lever <NUM> represents the transmission <NUM> operating in a torque ratio mode (TRM). The benefit of operating in TRM is that it allows the efficient operation of the powertrain at higher vehicle speeds, as is shown in <FIG>. The torque ratio mode is a CVT mode. The second motor <NUM> provides the reaction torque for the first motor <NUM> and vice versa. Since the ratios of the first motor <NUM> (A-Motor) are typically numerically larger than the numeric ratio of the second motor <NUM> (B-Motor), the torque provided by the second motor <NUM> will be the limiting torque. There are three formulas that must be adhered to in torque ratio mode. They include:
<MAT>
<MAT>
<MAT>
wherein MS1 and MS2 are defined as the moments about the first sun gear S1 and the second sun gear S2, respectively.

<FIG> show the first motor <NUM> and the second motor <NUM> operating at a defined torque, as represented by the horizontal lines showing constant torque and how the speed of the motors <NUM>, <NUM> varies to maximize efficiency. As with the speed ratio mode, the most efficient portion of the operation of the motors <NUM>, <NUM> is in the darkest portion of the graph which is the center portion. It is ideal to operate in this range of speeds to maximize the efficiency of the motors <NUM>, <NUM>.

Referring to <FIG>, a lever diagram showing the transmission <NUM> having two inputs (<FIG> and <FIG>) according to the invention is shown. The lever diagram is substantially similar to lever diagram for the single-input transmission shown in <FIG>. One difference between the two configurations is the transmission <NUM> has two input shafts <NUM>, <NUM>, wherein the first input shaft <NUM> receives torque from the first motor <NUM> (A-Motor) and the second input shaft <NUM> receives torque from the second motor <NUM> (B-Motor). Another difference between the two configurations is the use of two controllable clutches <NUM> (K23), <NUM> (K24) instead of the single controllable clutch <NUM> (K13).

The output of the first motor <NUM> (A-Motor) is received by the first input shaft <NUM> (shaft <NUM>), which is fixedly secured to the fourth rotating member <NUM> (sun gear S2) of the second gearset <NUM>. The output of the second motor <NUM> (B-Motor) is received by the second input shaft <NUM> (shaft <NUM>). The second input shaft <NUM> (shaft <NUM>) is connected to the first controllable clutch <NUM> (K23) and the second controllable clutch <NUM> (K24). The first controllable clutch <NUM> (K23) operates in both directions as is indicated by the diodes <NUM>, <NUM>, which are oriented in opposite directions. A switch <NUM> illustrates that the clutch <NUM> (K23) is controllable and may be locked or allowed to rotate in both directions. The second controllable clutch <NUM> (K24) operates in both directions, as is indicated by the diodes <NUM>, <NUM>, which are oriented in opposite directions. A switch <NUM> illustrates that the controllable clutch <NUM> (K24) is controllable and may be locked or allowed to rotate in both directions.

The first controllable clutch <NUM> (K23) couples the second input shaft <NUM> (shaft <NUM>) and the output shaft <NUM> (shaft <NUM>). The second controllable clutch <NUM> (K24) couples the second input shaft <NUM> (shaft <NUM>) with the fourth shaft <NUM> (shaft <NUM>). As discussed above, the output shaft <NUM> is fixedly secured to both the third rotating member <NUM> (ring R1) of the first gearset <NUM> and the fifth rotating member <NUM> (carrier C2) of the second gearset <NUM>.

The transmission <NUM> also includes a first controllable brake <NUM> (B04) that couples the first rotating member <NUM> (sun gear S1) of the first gearset <NUM> to the transmission housing <NUM>. The first controllable brake <NUM> also has the symbol B04 because it is a brake that connects the transmission housing <NUM> (shaft <NUM>) with a fourth shaft <NUM> (shaft <NUM>). The first controllable brake <NUM> is similar to the controllable clutches <NUM>, <NUM> in that it is represented by two diodes <NUM>, <NUM> representing operation in either direction. The first controllable brake <NUM> is different from the controllable clutches <NUM>, 142in that each direction of operation can be controlled independently of the other, as represented by the two switches <NUM>, <NUM>. Operation of the first controllable brake <NUM> will be discussed in greater detail subsequently.

This transmission <NUM> also includes a second controllable brake <NUM> (B05) which couples the second rotating member <NUM> (carrier C1) of the first gearset <NUM> and the sixth rotating member <NUM> (ring R2) of the second gearset <NUM> to the transmission housing <NUM>. The second controllable brake <NUM> differs from the first controllable brake <NUM> in that it only can control whether a notch plate <NUM> (shaft <NUM>) is rotating, or if it is tied to the transmission housing <NUM> and prevented from rotating. As such, the second controllable brake <NUM> only includes a single switch <NUM> representing the two states of the second controllable clutch <NUM> (B05) as being either on or off, and two diodes <NUM>, <NUM> indicate that the second controllable brake <NUM> (B05) can lock in both directions or it can move freely in both directions.

Because the first <NUM> and second <NUM> gearsets are ring-carrier/ring-carrier gearsets, the connections described in the power flow in <FIG>, and the first <NUM> and second <NUM> motor output shafts are coaxial, the second motor <NUM> (B-Motor) is able to drive the output shaft <NUM> (shaft <NUM>) directly. The number of modes of operation increase due to this capability. In the embodiments shown in the Figures, the first motor output shaft <NUM> extends through the second motor output shaft <NUM>. As such, the second motor output shaft <NUM> is hollow providing a space through which the first motor output shaft <NUM> extends.

In <FIG>, the steady-state lever <NUM> represent when the host vehicle is not in motion. The operational lever <NUM> represents when the vehicle is moving through the operation of the first motor <NUM> (A Motor) and/or the second motor <NUM> (B Motor). The first controllable clutch <NUM> (K23) is open as represented by the switch <NUM> being open. In addition, the second controllable clutch <NUM> (K24) is closed. Therefore, the second motor <NUM> (B Motor) is coupled to the first rotating member <NUM> (sun gear S1) of the first gearset <NUM>. The first rotating member <NUM> (sun gear S1) is not grounded to the transmission housing <NUM> because the first controllable brake <NUM> (B04) is open. Finally, the second controllable brake <NUM> (B05) is closed tying the second rotating member <NUM> (carrier C1) of the first gearset <NUM> and the sixth rotating member <NUM> (ring gear R2) of the second gearset <NUM> are ground to the transmission housing <NUM> through the notch plat <NUM> (shaft <NUM>).

In this configuration, the first motor <NUM> is operating in the forward direction, indicated by arrow <NUM>, and the second motor <NUM> is operating in the reverse direction, indicated by arrow <NUM>. By way of example, and in not to be limiting, exemplary torques are provided based on the designs of the gearsets <NUM>, <NUM> and the motors <NUM>, <NUM>. Given the output of the first motor <NUM> (A Motor) provides a torque of <NUM> on the second sun gear <NUM> (sun gear S2) and the output of the second motor <NUM> provides a torque of <NUM> in the opposite direction on the first rotating member <NUM> (sun gear S1) results in a torque of <NUM> on the second rotating member <NUM> (carrier C1) of the first gearset <NUM> and the sixth rotating member <NUM> (ring gear R2) of the second gearset <NUM> and an output torque of <NUM> at the output shaft <NUM>. This is "first gear.

Referring to <FIG>, this is the same embodiment as that of <FIG> with the transmission <NUM> in a different state. More specifically, the second motor <NUM> (B Motor) as an output of <NUM> in the forward direction as is indicated by arrow <NUM>. The first motor <NUM> (A Motor) continues to output a torque of <NUM> in the forward direction as is indicated by the forward arrow <NUM>. The first controllable clutch <NUM> (K23) is now closed and the second controllable clutch <NUM> is now open. With the first <NUM> and second <NUM> controllable brakes (B04 and B05) unchanged from the state they were in in <FIG>, the transmission <NUM> is in "second gear" with an output torque at the output shaft <NUM> of <NUM>.

Referring to <FIG>, the transmission <NUM> is now in "third gear. " This is done by unlocking the second controllable brake <NUM> (B05), as represented by the open switch <NUM>, and locking both directions of the first controllable brake <NUM>, as represented by closing the two switches <NUM>, <NUM> of the first controllable brake <NUM>. Continuing with the example, the output shaft <NUM> (shaft <NUM>) only receives <NUM> of force in third gear.

Referring to <FIG>, the transmission <NUM> is shown in "fourth gear. " Both controllable clutches <NUM>, <NUM> (K23, K24) are closed allowing the second motor <NUM> (B-Motor) to apply torque to the first rotating member <NUM> (sun gear S1) as well as the output shaft <NUM> (shaft <NUM>) via the combination of the third rotating member <NUM> (ring gear R1) and the fifth rotating member <NUM> (carrier C2). In addition, both controllable brakes <NUM>, <NUM> (B04, B05) are opened such that none of the rotating members <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are ground to the transmission housing <NUM>.

Referring to <FIG>, the transmission <NUM> is now in "reverse. " The first motor <NUM> (A-Motor) is run in the opposite direction, as is indicated by arrow <NUM>. The first controllable clutch <NUM> (K23) is open removing the second motor <NUM> (B-Motor) from being connected to the output shaft <NUM> (shaft <NUM>). The second controllable clutch <NUM> (K24) is closed providing a path for the torque generated by the second motor <NUM> (B-Motor) in the forward direction <NUM>, which is received by the first rotating member <NUM> (sun gear S1). The first controllable brake <NUM> (B04) is open so the first rotating member <NUM> (sun gear S1) is not ground to the transmission housing <NUM>. The second controllable brake <NUM> (B05) is closed tying the second rotating member <NUM> (carrier C1) and the sixth rotating member <NUM> (ring gear R2) to ground (transmission housing <NUM>). Continuing with the numerical example started above, <NUM> of reverse torque provided by the first motor <NUM> (A-Motor) and <NUM> of forward torque provided by the second motor <NUM> (B-Motor) will result in <NUM> of torque in the reverse direction at the output shaft <NUM> (shaft <NUM>).

<FIG> are simplified representations of how the first motor <NUM> (A-Motor) and the second motor <NUM> (B-Motor) act on the lever that extends through the four nodes created by the first <NUM> and second <NUM> gearsets. In <FIG>, the first motor <NUM> is effectively asserting a torque in the forward direction against the top node of the lever <NUM> and the second motor <NUM> is asserting a torque in the reverse direction against the bottom node of the lever <NUM>. The first motor <NUM> (A-Motor) maintains this configuration through <FIG>, which represents the first motor <NUM> (A-Motor) has the same output starting at "first gear" through "fourth gear. " This results in the output shaft <NUM> (shaft <NUM>) having a large torque in the forward direction commensurate with "first gear. " In <FIG>, the second motor <NUM> (B-Motor) is applying a forwardly directed torque against the second node from the top, which also represents the output shaft <NUM> (shaft <NUM>) and the second node of the four-node linkage (representing the second rotating member <NUM> (carrier C1) and the sixth rotating member <NUM> (ring gear R2)) is locked in place because the second controllable brake (B05) is grounding that node to the transmission housing <NUM>. In <FIG>, the motors <NUM>, <NUM> maintain the same configuration, but the bottom node of the four-node linkage, which is the first rotating member <NUM> (sun gear S1) is locked in place and cannot rotate due to the grounding of this member <NUM> to the transmission housing <NUM> (ground). In <FIG>, the motors <NUM>, <NUM> maintain the same connections but all of the nodes of the four-node linkage are free to rotate, which is represented by the fact that the lever is generally parallel to the lever <NUM> representing the vehicle existing at <NUM> mph (at zero speed). In <FIG>, the second node is again locked to ground. In this configuration, the second motor <NUM> (B-Motor) is again coupled to the first rotating member <NUM> (sun gear S1) and the first motor <NUM> (A-Motor) is running in reverse, resulting in the output shaft <NUM> (shaft <NUM>) having a torque in the reverse direction, such that the transmission <NUM> is in "reverse.

Referring to <FIG>, a table of the different modes in which the transmission operates based on the clutch activation is shown. For the varying modes, "A1B1" is "first gear," "A1B2" is "second gear," "A2B2" is "third gear, "A3B2" is fourth gear and "Rev" is "reverse. " The transmission <NUM> in the configuration shown in <FIG> and <FIG>also can operate in two additional modes, "Park" and "Hill Hold. " By turning both of the controllable brakes <NUM>, <NUM> on, the bottom two nodes of the four-node linkage are coupled to the transmission housing <NUM>, resulting in no movement of the transmission <NUM>. This is a "park" state preventing movement of the vehicle. In "Hill Hold" mode, only one of the diodes <NUM>, <NUM> is turned on, preventing the vehicle from rolling down a hill. This is useful when stopped on a hill. The direction the vehicle is in when it is on the hill will dictate which of the two switches <NUM>, <NUM> of the first controllable clutch <NUM> (B04) is turned on.

<FIG> and <FIG> are block diagrams of three types of four-node linkage relationships for transmissions having two sets of gears. <FIG> illustrates a Ravigneaux gearset and the respective four-node linkage representation thereof. <FIG> represents a ring-carrier/ring-carrier gearset and the respective four-node linkage representation thereof. And <FIG> illustrates a Simpson gearset and the respective four-node linkage representation thereof.

Referring to <FIG>, the transmission <NUM> is shown in a configuration that includes three inputs, which is not a part of the present invention. In the example embodiment shown, the three inputs include the first motor <NUM> (A-Motor), the second motor <NUM> (B-Motor) and an internal combustion engine <NUM> (ICE). As stated above, the elements described above will have the same reference characters in when described in this section. While some of the parenthetic nomenclature changes (additional shafts require different connections), the reference characters will remain unchanged from above.

The first controllable clutch <NUM> (K23), the second controllable clutch (K36), the first controllable brake <NUM> (B06), the second controllable brake (B07) and the four-node linkage representing first <NUM> and second <NUM> gearsets are all connected in the same configuration as was discussed above.

The addition of the internal combustion engine <NUM> (ICE) requires the addition of a third gearset <NUM> having a seventh rotating member <NUM> (sun gear S0), an eighth rotating member <NUM> (ring gear R0) and a ninth rotating member <NUM> (annulus A0). The output of the internal combustion engine <NUM> (ICE) is coupled to the eighth rotating member <NUM> (ring gear R0). The ninth rotating member <NUM> (annulus A0) is coupled to the first input shaft <NUM> (shaft <NUM>), which is coupled to the fourth rotating member <NUM> (sun gear S2). The seventh rotating member <NUM> (sun gear S0) is operatively connected to the second motor <NUM> (B-Motor) through a third controllable clutch <NUM> (K45).

The second motor <NUM> (B-Motor) is also coupled to the second controllable clutch <NUM> (K36) through a fourth controllable clutch <NUM> (K34). Finally, the second motor <NUM> (B-Motor) is also coupled to the transmission housing <NUM> (ground) through a third controllable brake <NUM> B04).

The operation of the transmission <NUM>, when it incorporates the use of the internal combustion engine <NUM> (ICE) as depicted in <FIG>, the modes of operation include the use of the transmission <NUM> without the use of the internal combustion engine <NUM> (ICE). This is the EV Mode (the first four rows of the table shown in <FIG>). Hybrid Mode is shown in the next four rows wherein the first motor <NUM> (A-Motor), the second motor <NUM> (B-Motor) and the internal combustion engine <NUM> (ICE) all provide torques during certain defined conditions in the operation of the vehicle. The transmission <NUM> may operate in gas only mode, as is indicated in the next two rows identified by "ICE. " These modes rely exclusively on the torque provided by the internal combustion engine <NUM> (ICE). "Park" Mode is the next row, which identifies when the vehicle has a zero speed and is not engaged to move. "Hill Hold" Mode is a mode that allows the vehicle to maintain a position on a hill while being ready to move in a direction opposite the direction of the hill. The last mode is "Generator" Mode whereby the vehicle can use the second motor <NUM> (B-Motor) as a generator to power or charge a device or circuit (neither shown) that is electrically connectable to an electrical port/outlet (not shown) that is electrically connected to the second motor <NUM> (B-Motor). The controllable clutches <NUM>, <NUM>, <NUM>, <NUM> and the controllable brakes <NUM>, <NUM>, <NUM> are identified in the table in <FIG> to show which of these devices are active to facilitate any one of the modes identified above and in <FIG>.

Referring to <FIG>, another example embodiment of the three-input configuration is shown. The difference between the example embodiment shown in <FIG> and that which is shown in <FIG> is the type of clutches used. In the example embodiment shown in <FIG>, the third controllable clutch <NUM> (K45), the fourth controllable clutch <NUM> (K34) and the third controllable brake <NUM> (B04) are all binary devices. These devices <NUM>, <NUM>, <NUM> are all replaced with a single three-position clutch <NUM>, wherein the three-position clutch <NUM> couples shaft <NUM> to shaft <NUM> connecting the second motor <NUM> (B-Motor) to the seventh rotating member <NUM> (sun gear S0) in one position; it couples the second motor <NUM> (B-Motor) to the second controllable clutch <NUM> (K36); or, it leaves the second motor <NUM> (B-Motor) detached from the rest of the transmission <NUM>.

Referring to <FIG>, the example embodiment shown is similar to that which is shown in <FIG>. In addition to the three-position clutch <NUM>, a brake <NUM> (B04) is added between the three-position clutch <NUM> and the seventh rotating member <NUM> (sun gear S0). This brake <NUM> (B04) grounds the seventh rotating member <NUM> (sun gear S0) to allow the internal combustion engine <NUM> (ICE) to operate in an overdrive mode.

Referring to <FIG>, block diagrams of the example embodiments shown in <FIG>, <FIG> and <FIG> are shown. These drawings represent how a transmission <NUM> would be laid out in design. In <FIG>, the block diagram represents the transmission <NUM> shown in the lever diagram of <FIG>. In <FIG>, the block diagram represents the transmission <NUM> shown in the lever diagram of <FIG> but with two two-way clutches instead of a three-way clutch. In <FIG>, the block diagram represents the transmission <NUM> shown in the lever diagram of <FIG>. Finally, in <FIG>, the block diagram represents the transmission <NUM> shown in the lever diagram of <FIG>.

Referring to <FIG>, <FIG> and <FIG>, different embodiments of the transmission <NUM> are shown in cross-section. The transmission <NUM> is modular in that it can be configured differently while maintaining almost all of the content inside the transmission housing <NUM> the same. The design of the transmission <NUM> allows it to be scaled up to handle larger ranges of torques based on the host vehicle into which the transmission <NUM> will be installed. In <FIG>, the first input shaft <NUM> is the only input shaft. This embodiment only uses one input from the first motor <NUM> (A-Motor). In a sense, this is the most basic configuration of the transmission <NUM>.

In the next iteration, shown in <FIG>, the transmission has two input shafts <NUM>, <NUM>. The first input shaft <NUM> has an outer diameter <NUM> and the second input shaft <NUM> has inner diameter <NUM>, with the outer diameter <NUM> of the first input shaft <NUM> being less than the inner diameter <NUM> of the second input shaft <NUM>. The first input shaft <NUM> extends through the second input shaft <NUM>. In the embodiment shown, the second input shaft <NUM> is a pocket plate. In order to accommodate the second input shaft <NUM>, the second controllable clutch <NUM> (K24), and little else, is added.

Taking the modularity to the next level, the housing cap <NUM> can be one of several housing caps <NUM> to be used. Each housing cap <NUM> is configured to be mounted to the transmission housing <NUM> whereby the housing cap <NUM> provides for a different operational configuration. Referring to <FIG>, the housing cap <NUM> is extends out further away from the transmission housing <NUM> more than the housing cap <NUM> of <FIG>. This is because the housing cap <NUM> of <FIG> houses a gearset <NUM> to be used as a torque multiplier. Because the transmission <NUM> is modular, the additional torque multiplier <NUM> can be added to the transmission <NUM> and the transmission <NUM> can be interchangeable between a version that has a torque multiplying gearset <NUM> (<FIG>) and a version that is supplied without a torque multiplying gearset <NUM> (<FIG>).

Claim 1:
A transmission assembly (<NUM>) comprising:
a transmission housing (<NUM>);
a first ring-carrier/ring-carrier gearset (<NUM>) including a first sun gear (<NUM>), a first carrier (<NUM>), and a first ring gear (<NUM>) disposed within said transmission housing (<NUM>);
a second ring-carrier/ring-carrier gearset (<NUM>) including a second sun gear (<NUM>), a second carrier (<NUM>) and a second ring gear (<NUM>) disposed within said transmission housing (<NUM>) adjacent said first ring-carrier/ring-carrier gearset (<NUM>);
an output shaft (<NUM>) connected to said first ring gear (<NUM>) of said first ring-carrier/ring-carrier gearset (<NUM>) and said second carrier (<NUM>) of said second ring-carrier/ring-carrier gearset (<NUM>);
a first input shaft (<NUM>) connected to said second sun gear (<NUM>) of said second ring-carrier/ring-carrier gearset (<NUM>);
a first controllable clutch (<NUM>) connected to said first sun gear (<NUM>) of said first ring-carrier/ring-carrier gearset (<NUM>);
a second input shaft (<NUM>) connected to said first controllable clutch (<NUM>) such that said first controllable clutch (<NUM>) selectively couples said second input shaft (<NUM>) to said first sun gear (<NUM>) of said first ring-carrier/ring-carrier gearset (<NUM>);
a second controllable clutch (<NUM>) selectively coupling said second input shaft (<NUM>) with said output shaft (<NUM>) through said first ring gear (<NUM>) of said first ring-carrier/ring-carrier gearset (<NUM>) and said second carrier (<NUM>) of said second ring-carrier/ring-carrier gearset (<NUM>);
a first controllable brake (<NUM>) selectively coupling said first sun gear (<NUM>) to said transmission housing (<NUM>); and
a second controllable brake (<NUM>)selectively coupling said first carrier (<NUM>) of said first ring-carrier/ring-carrier gearset (<NUM>) and said second ring gear (<NUM>) of said second ring-carrier/ring-carrier gearset (<NUM>) to said transmission housing (<NUM>), such that said first and second controllable clutches (<NUM>, <NUM>) and said first and second controllable brakes (<NUM>, <NUM>) control the torque of said output shaft (<NUM>) as a function of forces driving said first and second input shafts (<NUM>, <NUM>).