PARKING SYSTEM FOR TWIN-ENGINE DRIVE UNIT

Abstract

Drive unit (100) comprising: a first electric machine (102) with a first machine shaft (106); a second electric machine (104) with a second machine shaft (108); a differential (114) connecting the first electric machine (102) and the second electric machine (104), the differential (114) comprising a parking gear (116); a parking system (200) configured to engage with the parking gear (116) of the differential (114) to stop the rotation of both the first electric machine (102) and the second electric machine (104) simultaneously; the parking system (200) comprising a pawl (202) movable relative to the parking gear (116) between an engaged and a disengaged position; the pawl (202) being disengaged from the parking gear (116) of the differential in the disengaged position (114) is spaced apart to allow rotation of the parking gear (116);and wherein the pawl (202) in the engaged position is in contact with the parking gear (116) of the differential (114) to prevent rotation of the parking gear (116), thereby preventing rotation of the first machine shaft (106) of the first electric machine (102) and the second machine shaft (108) of the second electric machine (104), and wherein the differential (114) is a torque-preload differential (314).

Description

INTRODUCTION

[0001] The present disclosure relates to vehicles and in particular to a parking system for a twin-motor drive unit. DESCRIPTION

[0002] Vehicles can be equipped with a parking system to stop the rotation of moving components within a drive unit. However, it is desirable to minimize the size and number of parts required by the drive unit and the parking system to simplify manufacturing. Therefore, there is a need to develop a parking system that occupies as little space as possible within the vehicle.

[0003] Therefore, the present disclosure describes a vehicle with a differential that connects two motors. By connecting the two motors via a differential, the vehicle uses a parking system to stop the rotation of the two motors. A pawl of the parking system engages with a parking gear of the differential to ground the two motors and thus stop the wheels. In normal operation, the two motors can perform their respective functions independently.

[0004] In one aspect of the present disclosure, a drive unit comprises a first electric machine with a first machine shaft, a second electric machine with a second machine shaft, and a differential connecting the first electric machine and the second electric machine. The differential includes a parking gear. The drive unit includes a parking system configured to engage with the parking gear of the differential to stop the rotation of both the first electric machine and the second electric machine simultaneously. The parking system may be a single parking system. The parking system includes a pawl that is movable relative to the parking gear between an engaged position and a disengaged position. The pawl may be a single pawl.In the disengaged position, the pawl is spaced away from the differential's parking gear to allow the parking gear to rotate. In the engaged position, the pawl is in contact with the differential's parking gear to prevent rotation of the parking gear, thereby preventing rotation of the first machine shaft of the first electric motor and the second machine shaft of the second electric motor.

[0005] In one aspect of the present disclosure, the first machine shaft of the first electric machine is directly coupled to the differential. The second machine shaft of the second electric machine is also directly coupled to the differential. The single pawl is in direct contact with the parking gear of the differential when the single pawl is in the engaged position. The differential is an open differential.

[0006] In one aspect of the present disclosure, both the first machine shaft and the second machine shaft are rotatable independently of each other. The drive unit further comprises a first machine gear coupled around the first machine shaft and a second machine gear coupled around the second machine shaft.

[0007] In one aspect of the present disclosure, the drive unit further comprises a first transmission shaft coupled to the first machine shaft, such that torque is transmitted from the first electric machine to the first transmission shaft. The drive unit further comprises a second transmission shaft coupled to the second machine shaft, such that torque is transmitted from the second electric machine to the second transmission shaft. The first transmission shaft and the second transmission shaft are rotatable independently of each other. The first transmission shaft and the second transmission shaft are coaxial with each other. The first machine shaft extends along a first machine axis. The second machine shaft extends along a second machine axis. The first machine axis is coaxial with the second machine axis.The first transmission shaft extends along a first transmission axis. The second transmission shaft extends along a second transmission axis; the first transmission axis is coaxial with the second transmission axis, and the first machine axis is parallel to the first transmission axis.

[0008] In one aspect of the present disclosure, the drive unit further comprises a first shaft gear coupled around the first shaft gear. The first shaft gear is in mesh with the first machine gear, so that a torque is transmitted from the first electric machine to the first transmission shaft. The drive unit comprises a second shaft gear coupled around the second shaft gear. The second shaft gear is in mesh with the second machine gear, so that a torque is transmitted from the second electric machine and the second shaft gear.

[0009] In one aspect of the present disclosure, the first transmission shaft comprises a first internal gear. The second transmission shaft comprises a second internal gear. The drive unit further comprises a first output shaft and a second output shaft. The first output shaft and the second output shaft are arranged coaxially with each other. The first output shaft comprises a first output gear that meshes with the first internal gear, such that torque is transmitted from the first transmission shaft to the first output shaft. The second output shaft comprises a second output gear that meshes with the second internal gear, such that torque is transmitted from the second transmission shaft to the second output shaft. The first output shaft and the second output shaft are independently rotatable.

[0010] In one aspect of the present disclosure, the differential can be a torque preload differential.

[0011] In one aspect of the present disclosure, the drive unit also comprises at least one planetary gear unit coupled to at least one of the first electric machine or the second electric machine.

[0012] In one aspect of the present disclosure, the first machine shaft and the second machine shaft are not coaxial. The drive unit further comprises a chain that connects the first machine shaft and the second machine shaft through the differential.

[0013] In one aspect of the present disclosure, the drive unit further comprises a first transfer case and a second transfer case. The first transfer case connects the differential to the first electric machine. The second transfer case connects the differential to the second electric machine. The first machine shaft and the second machine shaft are not coaxial.

[0014] The present disclosure also describes a vehicle system. In one aspect of the present disclosure, the vehicle system comprises a vehicle body and a drive unit (as described above) arranged within the vehicle body.

[0015] The above features and advantages, as well as other features and advantages of the present teaching, are readily apparent from the following detailed description of some of the best modes and other embodiments for carrying out the present teaching as defined in the attached claims, when considered in conjunction with the attached drawings. List of characters

[0016] The present revelation is described in connection with the following figures, in which the same reference numbers stand for the same elements. Fig. Figure 1 is a schematic side view of a vehicle with a drive unit that includes a parking gear. Fig. Figure 2 is a schematic, side sectional view of the drive unit of Fig. 1. Fig. Figure 3 is a schematic, perspective view of a parking system for the drive unit of Fig. 1. Fig. Figure 4 is a schematic, lateral sectional view of the drive unit according to one aspect of the present disclosure, wherein the drive unit comprises a torque preload differential. Fig. Figure 5 is a schematic, side sectional view of the drive unit according to one aspect of the present disclosure, wherein the drive unit comprises electric machines, a differential and planetary gears near the differential to reduce the output speed of the electric machines. Fig. Figure 6 is a schematic sectional view of the drive unit according to one aspect of the present disclosure, wherein the drive unit comprises electric machines, a differential and planetary gear sets spaced apart from the differential for reducing the output speed of the electric machines. Fig. Figure 7 is a schematic side view of the drive unit according to one aspect of the present disclosure, wherein the drive unit comprises electrical machines, a differential and a chain coupled between the electrical machines. Fig. Figure 8 is a schematic side view of the drive unit according to one aspect of the present disclosure, wherein the drive unit comprises electric machines, a differential and distribution gears coupled between the electric machines. DETAILED DESCRIPTION

[0017] The following detailed description is merely exemplary and is not intended to limit its application and use. Furthermore, there is no intention to be bound by any express or implied theories presented in the preceding technical section, background, summary, or the detailed description that follows. As used herein, the term "module" refers to hardware, software, firmware, electronic control components, processing logic, and / or processors, individually or in combination, including, but not limited to: application-specific integrated circuits (ASICs), electronic circuits, processors (common, dedicated, or group), and memory executing one or more software or firmware programs, combinational logic circuits, and / or other suitable components providing the described functionality.

[0018] Embodiments of the present disclosure can be described herein in the form of functional and / or logical block components and various processing steps. Such block components can be implemented by a number of hardware, software, and / or firmware components configured to perform the specified functions. For example, an embodiment of the present disclosure may employ various integrated circuit components, such as memory elements, digital signal processing elements, logic elements, lookup tables, or the like, which can perform a variety of functions under the control of one or more microprocessors or other control devices.Furthermore, the person skilled in the art will recognize that embodiments of the present disclosure can be practiced in connection with a number of systems and that the systems described here are merely exemplary embodiments of the present disclosure.

[0019] For the sake of brevity, techniques for signal processing, data fusion, signaling, control, and other functional aspects of the systems (and the individual operating components of the systems) are not described in detail here. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or physical couplings between the different elements. It should be noted that alternative or additional functional relationships or physical connections may exist in an embodiment of this disclosure.

[0020] Referring to Fig. The vehicle 10 comprises a vehicle body 12 and a plurality of wheels 14 connected to the vehicle body 12. Each wheel 14 can be attached to a tire 16. In the illustrated embodiment, the vehicle 10 is configured as a sedan. However, it is conceivable that the vehicle 10 could have suitable configurations, such as a pickup truck, an SUV, etc. The vehicle 10 can also be referred to as the vehicle system and includes a drive unit 100.

[0021] As in Fig. As shown in Figure 2, the drive unit 100 comprises a first electric machine 102 and a second electric machine 104. Both the first electric machine 102 and the second electric machine 104 can operate as electric motors and thus convert electrical energy into mechanical energy. However, it is also conceivable that the first electric machine 102 and the second electric machine 104 could function as generators and thus convert mechanical energy into electrical energy. The first electric machine 102 comprises a first machine shaft 106 extending along a first machine axis M1. The second electric machine 104 comprises a second machine shaft 108 extending along a second machine axis M2. The first machine axis M1 and the second machine axis M2 can be coaxial to minimize the space required by the drive unit 100 and to facilitate its manufacture.The first electric machine 102 and the second electric machine 104 can be supported by bearings 110, such as ball bearings. The drive unit 100 can also include a housing 112 in which the first electric machine 102 and the second electric machine 104 are housed.

[0022] The drive unit 100 comprises a differential 114 that connects the first electric machine 102 and the second electric machine 104. In the illustrated embodiment, the differential 114 is an open differential and is directly connected to the first machine shaft 106 and the second machine shaft 108 to improve the structural connection between the differential 114 and the first electric machine 102 and the second electric machine 104. The drive unit 100 can contain only one differential 114 connecting the first electric machine 102 and the second electric machine 104 to minimize the number of parts and simplify manufacturing. Therefore, the drive unit 100 can comprise only the first electric machine 102 and the second electric machine 104 to minimize the number of parts and simplify manufacturing.In other words, the drive unit 100 can only include two electric machines (i.e., the first electric machine 102 and the second electric machine 104) in order to minimize the number of parts and to facilitate manufacturing, and therefore the drive unit 100 can be called a double-motor drive unit.

[0023] As described below, the drive unit 100 comprises a single parking system 200 configured to lock the differential 114 in place, thus preventing movement of both the first machine shaft 106 and the second machine shaft 108 of the first electric machine 102 and the second electric machine 104, respectively. In other words, the drive unit 100 contains no other parking systems besides the parking system 200. The inclusion of the single parking system 200 simplifies the manufacture of the drive unit 100. The differential 114 includes a parking gear 116, and the parking system 200 is configured to engage with the parking gear 116 to simultaneously stop and prevent the rotation of the first machine shaft 106 and the second machine shaft 108 of the first electric machine 102 and the second electric machine 104, respectively.As explained below, the parking system 200 comprises a single pawl 202 which is positioned relative to the parking gear 116 between an inset position (as in . Fig. 2 shown) and a displaced position (as in Fig. (Figure 3) is movable. When the single pawl 202 is in the disengaged position, the pawl 202 is spaced and does not necessarily contact the parking gear 116 of the differential 114, allowing the parking gear 116 to rotate. Consequently, the first machine shaft 106 and the second machine shaft 108 of the first electric machine 102 and the second electric machine 104, respectively, can rotate freely when the pawl 202 is in the disengaged position. When the pawl 202 is in the engaged position, the pawl 202 is in direct contact with the parking gear 116 of the differential 114, thus preventing the parking gear 116 from rotating. Consequently, the first machine shaft 106 and the second machine shaft 108 of the first electric machine 102 and the second electric machine 104 respectively cannot rotate when the pawl 202 is in the engaged position.

[0024] As in Fig. As shown in Figure 3, the parking system 200 comprises the pawl 202, which is configured to engage with the parking gear 116. The parking gear 116 can be configured as a spur gear and comprises a main gear body 118 and a plurality of teeth 120 extending from the main gear body 118. The parking gear 116 defines a gap 122 between any two teeth 120. Each gap 122 of the parking gear 116 is dimensioned to accommodate a pawl tooth 204 of the pawl 202. The pawl 202 comprises a pawl body 206. The pawl tooth 204 projects directly from the pawl body 206 and is dimensioned to accommodate each gap 122 of the parking gear 116. When the pawl 202 is in the engaged position, the pawl tooth 204 is positioned within one of the recesses 122 of the parking gear 116 to prevent the parking gear 116 from rotating.If the parking gear 116 does not rotate, the first machine shaft 106 and the second machine shaft 108 of the first electric machine 102 and the second electric machine 104 respectively cannot rotate either.

[0025] The parking system 200 comprises a fixed support 208, which may be designed as a metal frame, and a pivot pin 210 that connects the pawl 202 and the fixed support 208. The pawl 202 is therefore pivotable about the pivot pin 210 relative to the fixed support 208 in the direction indicated by the double arrow ED. The parking system 200 further comprises an actuating shaft 212, which is coupled to the pawl 202 and movable relative to the pawl 202 in the direction indicated by the double arrow FB, in order to move the pawl tooth 204 towards and away from the parking gear 116. The parking system 200 may include a preloading element 214, such as a coil spring, to preload the actuating shaft 212 in a forward direction towards the pivot pin 210.

[0026] Back to Fig. 2: The drive unit 100 comprises a first machine gear 124, which is coupled around the first machine shaft 106, and a second machine gear 126, which is coupled around the second machine shaft 108. Accordingly, the first machine gear 124 rotates in sync with the first machine shaft 106 and the second machine gear 126 rotates in sync with the second machine shaft 108.

[0027] The drive unit 100 further comprises a first transmission shaft 128 and a second transmission shaft 130, which are rotatable independently of each other. The first transmission shaft 128 extends along a first transmission axis T1, and the second transmission shaft 130 extends along the second transmission axis T2. The first transmission axis T1 and the second transmission axis T2 are coaxial to facilitate manufacturing. Each of the first machine axis M1 and the second machine axis M2 is parallel to each of the first transmission axis T1 and the second transmission axis T2, respectively, to facilitate manufacturing. The drive unit 100 further comprises a first gear shaft 132 coupled around the first transmission shaft 128 and a second gear shaft 134 coupled around the second transmission shaft 130.The first shaft gear 132 rotates in sync with the first transmission shaft 128, and the second shaft gear 134 rotates in sync with the second transmission shaft 130. The first shaft gear 132 is meshed with the first machine gear 124. Accordingly, the torque from the first electric machine 102 is transmitted to the first transmission shaft 128. The gear of the second shaft 134 meshes with the gear of the second machine 126. Accordingly, the torque from the second electric machine 104 is transmitted to the second transmission shaft 130. The first transmission shaft 128 contains a first internal gear 136, and the second transmission shaft 130 contains a second internal gear 138.

[0028] The drive unit 100 further comprises a first output shaft 140 and a second output shaft 142, each of which transmits a torque to the wheels 14 ( Fig. 1) The first output shaft 140 extends along a first output axis OS1, and the second output shaft 142 extends along a second output axis OS2. In the illustrated embodiment, both the first output axis OS1 and the second output axis OS2 are arranged parallel to the first transmission axis T1 and the second transmission axis T2, respectively, to facilitate manufacturing. In the illustrated embodiment, the first output axis OS1 and the second output axis OS2 are coaxial to minimize the space occupied by the drive unit 100. The first output shaft 140 includes a first output gear 144, and the second output shaft 142 includes a second output gear 146. The first output gear 144 meshes with the first internal gear 136. Thus, the torque is transmitted from the first transmission shaft 128 to the first output shaft 140.The torque is then transmitted from the first output shaft to one of the wheels 14 (. Fig. 1) The second output gear 146 is engaged with the second internal gear 138. In this way, the torque is transmitted from the second transmission shaft 130 to the second output shaft 142. The torque is then transmitted from the second output shaft 142 to one of the gears 14 ( Fig. 1) The first output shaft 140 and the second output shaft 142 rotate independently of each other.

[0029] Fig. Figure 4 shows a drive unit 300 according to a further aspect of the present disclosure. The design and function of the drive unit 300 is essentially identical to the design and function of the drive unit 100 described above, except for the features described below. The drive unit 300 comprises a torque-preload differential 314 coupled between the first electric machine 102 and the second electric machine 104. The preload differential 314 also includes a parking gear 116 configured to engage with the single pawl 202 ( Fig. 2 and Fig. 3) When the preload differential 314 is used, a certain torque can be applied to wheel 14 ( Fig. 1) be transferred, which has better traction than wheel 14, which is spinning.

[0030] Fig. Figure 5 shows a drive unit 400 according to a further aspect of the present disclosure. The construction and function of the drive unit 400 is essentially identical to the construction and function of the drive unit 100 described above, except for the features described below. The drive unit 400 comprises a first planetary gear set 402 coupled to the first electric machine 102, and a second planetary gear set 404 coupled to the second electric machine 104. The first planetary gear set 402 serves as a first-stage reduction gear to reduce the output speed of the first electric machine 102, and the second planetary gear set 404 serves as a first-stage reduction gear to reduce the output speed of the second electric machine 104. The drive unit 400 does not include the first transmission shaft 128 ( Fig. 2) and the second transmission wave 130 ( Fig. 2) Rather, the torque from the first electric machine 102 is transmitted via the first planetary gear 402 to the first output shaft 140, and the torque from the second electric machine 104 is transmitted via the second planetary gear 404 to the second output shaft 142. The differential 114 includes the parking gear 116, which is configured to engage with the pawl 202 ( Fig. 2 and Fig. 3) This configuration is more compact than the others in the Fig. 2, Fig. 4 and Fig. 5 configurations shown.

[0031] Fig. Figure 6 shows a drive unit 500 according to a further aspect of the present disclosure. The construction and function of the drive unit 500 is essentially identical to the construction and function of the drive unit 100 described above, with the exception of the features described below. In this embodiment, only the first planetary gear set 402 and the second planetary gear set 404 are used to reduce the output speed of the first electric machine 102 and the second electric machine 104, respectively. The drive unit 500 does not include the first transmission shaft 128 ( Fig. 2), the second transmission wave 130 ( Fig. 2), the first output wave 140 ( Fig. 2) and the second output wave 142 ( Fig. 2) The differential 114 includes the parking gear 116, which is configured to engage with the pawl 202 ( Fig. and Fig. ).

[0032] Fig. Figure 7 shows a drive unit 700 according to another aspect of the present disclosure. The structure and function of the drive unit 700 are essentially identical to the structure and function of the drive unit 100 described above, except for the features described below. In the illustrated embodiment, the first machine axis M1 of the first electric machine 102 is not coaxial with the second machine axis M2 of the second electric machine 104. However, the second machine axis M2 is parallel to the first machine axis M1. The drive unit 700 comprises a chain 702 that connects the first electric machine 102 and the second electric machine 104 via the differential 114. The drive unit 700 may include a first sprocket 704 connected to the chain 702 and the first electric machine 102, and a second sprocket 706 connected to the chain 702 and the differential 114.The first pinion 704 rotates around the first machine axis M1 and the second pinion 706 rotates around the second machine axis M2. The differential 114 includes the parking gear 116, which is configured to engage with the pawl 202 (. Fig. 2 and Fig. 3).

[0033] Fig. Figure 8 shows a drive unit 800 according to another aspect of the present disclosure. The design and function of the drive unit 800 are essentially identical to the design and function of the drive unit 100 described above, except for the features described below. In the embodiment shown, the drive unit 100 comprises a first distribution gearbox 802 and a second distribution gearbox 804. The first distribution gearbox 802 connects the differential 114 to the first electric machine 102. The second distribution gearbox 804 connects the differential 114 to the second electric machine 104, and the first machine shaft and the second machine shaft are not coaxial. Both the first distribution gearbox 802 and the second distribution gearbox 804 rotate about a distribution gearbox axis TG, which is parallel to the first machine axis M1 and the second machine axis M2.The first machine axis M1 and the second machine axis M2 are not coaxial. The first machine axis M1 is parallel to the second machine axis M2. The differential 114 includes the parking gear 116, which is configured to engage with the pawl 202 (. Fig. 2 and Fig. 3).

[0034] The detailed description and the drawings or illustrations are a supporting description of the present teaching, but the scope of the present teaching is defined exclusively by the claims. While some of the best modes and other embodiments for carrying out the present teaching have been described in detail, there are various alternative designs and embodiments for carrying out the present teaching, which are defined in the accompanying claims.

Claims

[1] Drive unit comprising: a first electric machine with a first machine shaft; a second electric machine with a second machine shaft; a differential connecting the first electric machine and the second electric machine, the differential comprising a parking gear; a parking system configured to engage with the parking gear of the differential to stop the rotation of both the first electric machine and the second electric machine simultaneously; wherein the parking system has a pawl which is movable relative to the parking gear between an engaged and an disengaged position; wherein the pawl in the disengaged position is spaced apart from the parking gear of the differential to allow rotation of the parking gear; and wherein the pawl in the engaged position is in contact with the parking gear of the differential to prevent rotation of the parking gear, thereby preventing rotation of the first machine shaft of the first electric machine and the second machine shaft of the second electric machine. [2] Drive unit according to claim 1, wherein the parking system is a single parking system, the pawl is a single pawl, the first machine shaft of the first electric machine is directly coupled to the differential, the second machine shaft of the second electric machine is directly coupled to the differential, the single pawl is in direct contact with the parking gear of the differential when the single pawl is in the engagement position, and the differential is an open differential. [3] Drive unit according to claim 2, wherein both the first machine shaft and the second machine shaft are rotatable independently of each other and the drive unit further comprises a first machine gear coupled around the first machine shaft and a second machine gear coupled around the second machine shaft. [4] Drive unit according to claim 3, further comprising a first transmission shaft coupled to the first machine shaft so that the torque is transmitted from the first electric machine to the first transmission shaft, the drive unit further comprising a second transmission shaft coupled to the second machine shaft so that the torque is transmitted from the second electric machine to the second transmission shaft, the first transmission shaft and the second transmission shaft are rotatable independently of each other, the first transmission shaft and the second transmission shaft are coaxial to each other, the first machine shaft extends along a first machine axis, the second machine shaft extends along a second machine axis, the first machine axis is coaxial with the second machine axis, the first transmission shaft extends along a first transmission axis,the second transmission shaft extends along a second transmission axis, the first transmission axis is coaxial with the second transmission axis, and the first machine axis is parallel to the first transmission axis. [5] Drive unit according to claim 4, further comprising a first shaft gear coupled around the first shaft gear, wherein the first shaft gear engages with the first machine gear, so that a torque is transmitted from the first electric machine to the first transmission shaft, the drive unit comprising a second shaft gear coupled around the second shaft gear, wherein the second shaft gear engages with the second machine gear, so that a torque is transmitted from the second electric machine and the second shaft gear. [6] Drive unit according to claim 5, wherein the first transmission shaft has a first internal gear, the second transmission shaft has a second internal gear, the drive unit further comprises a first output shaft and a second output shaft, the first output shaft and the second output shaft are coaxial to each other, the first output shaft has a first output gear which engages with the first internal gear so that a torque is transmitted from the first transmission shaft to the first output shaft, the second output shaft has a second output gear which engages with the second internal gear so that a torque is transmitted from the second transmission shaft to the second output shaft, and the first output shaft and the second output shaft are rotatably independent of each other. [7] Drive unit according to claim 1, wherein the differential is a torque bias differential. [8] Drive unit according to claim 1, further comprising at least one planetary gear unit coupled to at least one of the first electric machine or the second electric machine. [9] Drive unit according to claim 1, wherein the first machine shaft and the second machine shaft are not coaxial and the drive unit further comprises a chain connecting the first machine shaft and the second machine shaft via the differential. [10] Drive unit according to claim 1, further comprising a first transfer case and a second transfer case, wherein the first transfer case connects the differential to the first electric machine, the second transfer case connects the differential to the second electric machine and the first machine shaft and the second machine shaft are not coaxial.

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