Power transmission device for vehicle

Abstract

To provide a power transmission device for a vehicle capable of controlling differential motion of a pair of right and left wheels while suppressing increase of vehicle weight.SOLUTION: The vehicular power transmission device 20 includes a right wheel axle 42R, a motor generator 50 having a stator 52 and a rotor 54 relatively rotatable around an axis Cmg1, and an electronic control device 90. (a) a ratio α 1 (= NwR / Nd) of the right wheel speed NwR to the differential-case rotation speed Nd is equal to a ratio α 2 (= Nr / Ns) of the rotor rotation speed Nr to the stator rotation speed Ns, (b) the stator 52 has a coil 52c, (c) the rotor 54 generates a rotating magnetic field for the stator 52 in accordance with the relative rotation between the stator 52 and the rotor 54, and (d) the electronic control device 90 is configured to control the rotation of the motor generator 50 in accordance with a predetermined condition when the predetermined condition is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power transmission device for a vehicle that includes a differential gear, an axle, and a motor generator. [Background technology]

[0002] There is known a power transmission device for a vehicle in which a pair of left and right axles are each provided with a sliding constant velocity joint, and an electric limited slip differential that limits the differential between the pair of left and right wheels is provided in the outer race of each sliding constant velocity joint. For example, the power transmission device for a vehicle described in Patent Document 1 is such a power transmission device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-217430 Summary of the Invention [Problem to be solved by the invention]

[0004] In the power transmission device for a vehicle described in Patent Document 1, a limited slip differential is provided for each of the sliding constant velocity joints provided on a pair of left and right axles, which increases the number of components mounted on the vehicle and may result in an increase in the vehicle's weight.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a power transmission device for a vehicle that makes it possible to control the differential between a pair of left and right wheels while suppressing an increase in vehicle weight. [Means for solving the problem]

[0006] The gist of the present invention is a power transmission device for a vehicle comprising: a differential gear rotatable around a first axis; an axle connecting the differential gear to one of a pair of left and right wheels; a motor generator having a first rotating element and a second rotating element that can rotate relatively around a second axis; and a control device that controls the rotation of the motor generator, wherein (a) the ratio of the rotational speed of the axle to the rotational speed of the differential case of the differential gear is the same as the ratio of the rotational speed of the second rotating element to the rotational speed of the first rotating element; (b) one of the first rotating element and the second rotating element has a coil; (c) the other of the first rotating element and the second rotating element generates a rotating magnetic field for one of the first rotating element and the second rotating element in accordance with the relative rotation between the first rotating element and the second rotating element; and (d) the control device is configured to control the rotation of the motor generator in accordance with a predetermined condition when the predetermined condition is met. [Effects of the Invention]

[0007] According to the vehicle power transmission device of the present invention, (a) the ratio of the rotational speed of the axle to the rotational speed of the differential case of the differential gear is the same as the ratio of the rotational speed of the second rotating element to the rotational speed of the first rotating element, (b) one of the first rotating element and the second rotating element has a coil, (c) the other of the first rotating element and the second rotating element generates a rotating magnetic field for one of the first rotating element and the second rotating element in response to relative rotation between the first rotating element and the second rotating element, and (d) the control device is configured to control the rotation of the motor generator in response to a predetermined condition when the predetermined condition is met. The ratio of the rotational speed of the axle to the rotational speed of the differential case is the same as the ratio of the rotational speed of the second rotating element to the rotational speed of the first rotating element in the motor generator. Furthermore, one of the first rotating element and the second rotating element in the motor generator has a coil, and the other generates a rotating magnetic field in response to relative rotation. Such a motor generator is provided on an axle connecting the differential gear and one of the pair of left and right wheels. On the other hand, such a motor generator may not be provided on an axle connecting the differential gear and the other of the pair of left and right wheels. Furthermore, the differential between the pair of left and right wheels is controlled by a control device controlling the rotation of the motor generator in accordance with predetermined conditions. This makes it possible to reduce the number of motor generators mounted on the vehicle, thereby enabling differential control between the pair of left and right wheels while suppressing an increase in vehicle weight. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a configuration of a power transmission device for a vehicle according to a first embodiment. [Figure 2] 2 is an example of a flowchart illustrating a main part of the control operation of the electronic control device shown in FIG. [Figure 3] 3 is a diagram for schematically explaining the control of the state of backlash in S70 when the determination in S50 shown in FIG. 2 is YES. FIG. [Figure 4]3 is a diagram for schematically explaining the control of the state of backlash in S70 when the determination in S60 shown in FIG. 2 is YES. FIG. [Figure 5] FIG. 6 is a diagram illustrating the configuration of a power transmission device for a vehicle according to a second embodiment. [Figure 6] FIG. 10 is a diagram illustrating the configuration of a power transmission device for a vehicle according to a third embodiment. [Figure 7] FIG. 10 is a diagram illustrating the configuration of a power transmission device for a vehicle according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. Note that in each embodiment, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of each part are not necessarily drawn accurately. [Example]

[0010] FIG. 1 is a diagram illustrating the configuration of a vehicle power transmission device 20 according to a first embodiment.

[0011] The vehicle power transmission device 20 is mounted on a vehicle 10. The vehicle power transmission device 20 is a device that transmits power from a differential gear 30 to a pair of left and right wheels 14. The pair of left and right wheels 14 are drive wheels and include a left wheel 14L and a right wheel 14R.

[0012] The vehicle power transmission device 20 includes a differential gear 30, a pair of left and right axles (=drive shafts) 42, a motor generator 50, an inverter 60, a battery 62, and an electronic control device 90. The pair of left and right axles 42 are connected to the differential gear 30 and each of the pair of left and right wheels 14. Specifically, the left axle 42L of the pair of left and right axles 42 is connected to the left wheel 14L, and the right axle 42R of the pair of left and right axles 42 is connected to the right wheel 14R.

[0013] The differential gear 30 includes a differential case 32, a pinion shaft 34, a pair of differential pinions 36, a pair of side gears 38, and a differential ring gear 40. The differential case 32 is supported by a non-rotating case (e.g., a transaxle case) via bearings (not shown) and is rotatable about a first axis C1. Both ends of the cylindrical pinion shaft 34 are held by the differential case 32, so that the pinion shaft 34 rotates integrally with the differential case 32 about the first axis C1. Each of the pair of differential pinions 36 is, for example, a bevel gear, and is rotatably fitted to the outer periphery of the pinion shaft 34. The pair of side gears 38 are, for example, bevel gears, and mesh with each of the pair of differential pinions 36 and are rotatable about the first axis C1. The differential ring gear 40 is fixed to the differential case 32 by, for example, a bolt.

[0014] The pair of side gears 38 each have a cylindrical fitting hole formed on the inner periphery of the first axis C1, and a pair of left and right axles 42 are inserted into the fitting holes and connected by spline fitting. Power input from the differential ring gear 40 is transmitted to the differential case 32, and then transmitted to the pair of left and right axles 42 via the pinion shaft 34, the pair of differential pinions 36, and the pair of side gears 38. The differential gear 30 receives the power input from the differential ring gear 40 and transmits equal driving torque to the pair of left and right axles 42 while allowing for an appropriate difference in rotational speed. The first axis C1 is the rotation axis of the differential gear 30 and also the rotation axis of the pair of left and right axles 42.

[0015] The motor generator 50 functions as both a prime mover and a generator. The axis Cmg1 is the rotational axis of the motor generator 50. In this embodiment, the axis Cmg1 is the same rotational axis as the first axis C1. The axis Cmg1 corresponds to the "second axis" in the present invention. The motor generator 50 has a stator 52 and a rotor 54 that are rotatable relative to each other about the axis Cmg1. Although the term "stator" is used in this specification to facilitate understanding of the invention, the "stator 52" is not fixed to a non-rotating member. Furthermore, the stator 52 and the rotor 54 are rotatable relative to each other about the axis Cmg1. For example, the motor generator 50 has substantially the same configuration as a so-called synchronous motor, except that the stator 52 is rotatable. Therefore, the motor generator 50 can be drive-controlled to generate a relative rotation of the rotor 54 with respect to the stator 52, i.e., a differential rotation ΔN1 [rpm], or can be regeneratively controlled to generate power based on the differential rotation ΔN1. The differential rotation ΔN1 is the rotation speed (=Nr-Ns) obtained by subtracting the stator rotation speed Ns [rpm] from the rotor rotation speed Nr [rpm]. The stator rotation speed Ns is the rotation speed of the stator 52, and corresponds to the "rotation speed of the first rotating element" in this invention. The rotor rotation speed Nr is the rotation speed of the rotor 54, and corresponds to the "rotation speed of the second rotating element" in this invention.

[0016] The rotor 54 has, for example, a cylindrical rotor core and permanent magnets 54m attached to the outer surface of the rotor core. The permanent magnets 54m have north and south poles arranged alternately in the circumferential direction of the rotor core. The rotor 54 generates a rotating magnetic field based on the permanent magnets 54m for the stator 52 in response to the differential rotation ΔN1. The stator 52 has, for example, a cylindrical stator core and coils 52c wound in grooves, i.e., slots, formed in the inner periphery of the stator core. The outer periphery of the rotor 54 and the inner periphery of the stator 52 face each other in the radial direction centered on the axis Cmg1. The "stator 52" and "rotor 54" correspond to "one of the first and second rotating elements" and "the other of the first and second rotating elements," respectively, in this invention.

[0017] The rotation of the differential case 32 and the rotation of the right wheel axle 42R are transmitted to the motor generator 50. The "right wheel axle 42R" corresponds to the "axle connecting the differential gear to one of the pair of left and right wheels" in this invention. Specifically, the differential case 32 is connected to the stator 52 by spline fitting, and the right wheel axle 42R is connected to the rotor 54 by spline fitting. The rotation speed of the differential case 32 is referred to as the "differential case rotation speed Nd" [rpm]. The rotation speed of the right wheel axle 42R is equal to the right wheel speed NwR [rpm], which is the rotation speed of the right wheel 14R. The right wheel speed NwR corresponds to the "axle rotation speed" in this invention. The ratio α1 (= NwR / Nd) of the right wheel speed NwR to the differential case rotation speed Nd is the same as the ratio α2 (= Nr / Ns) of the rotor rotation speed Nr to the stator rotation speed Ns. The ratio α1 corresponds to the "ratio of the rotation speed of the axle to the rotation speed of the differential case" in this invention, and the ratio α2 corresponds to the "ratio of the rotation speed of the second rotating element to the rotation speed of the first rotating element" in this invention.

[0018] The inverter 60 is a power supply circuit provided between the motor generator 50 and the battery 62, and is controlled by an electronic control device 90 to convert direct current to alternating current and vice versa. The inverter 60 and the coil 52c of the motor generator 50 are electrically connected via a slip ring 58. The slip ring 58 is a mechanism including an annular electric circuit provided on the outer circumferential surface of the stator core of the stator 52 and brushes that contact the electric circuit. The battery 62 is a rechargeable secondary battery. The battery 62 is used to supply power to drive the motor generator 50 and to store electric power generated by the motor generator 50 through regeneration.

[0019] The electronic control device 90 includes, for example, a so-called microcomputer, and performs signal processing in accordance with pre-stored programs to execute various controls of the vehicle power transmission device 20. The "electronic control device 90" corresponds to the "control device" of the present invention. The electronic control device 90 receives various signals (e.g., the wheel speed Nw [rpm] of the pair of left and right wheels 14 (left wheel speed NwL and right wheel speed NwR), the steering angle φste [deg] of the steering wheel 68 provided on the vehicle 10, the accelerator opening θacc [%] which is the amount of accelerator operation indicating the magnitude of the driver's acceleration operation, the brake operation amount θbrk [%] which indicates the amount of deceleration operation required by the driver, the vehicle speed V [km / h], the stator rotation speed Ns and the rotational angle θs [deg] which indicate the rotational position of the stator 52, the rotor rotation speed Nr and the rotational angle θr [deg] which indicates the rotational position of the rotor 54, etc.) based on detection values ​​from various sensors (e.g., wheel speed sensor 70, steering angle sensor 72, accelerator opening sensor 74, brake operation amount sensor 76, vehicle speed sensor 78, stator rotation sensor 80, rotor rotation sensor 82, etc.). The electronic control device 90 outputs an MG control signal Smg to the inverter 60 for controlling the rotation of the motor generator 50 (drive control or regeneration control), for example.

[0020] When the absolute value of the steering angle φste is less than a steering angle determination value φste_jdg (>0), the electronic control device 90 is configured to cause the motor generator 50 to output a rotation difference cancellation torque Tcncl [N·m] in order to improve the straight-line running performance of the vehicle 10. The "steering angle determination value φste_jdg" is a predetermined determination value near zero that is determined experimentally or by design as the steering angle φste at which the driver is considered to intend straight-line running. The rotation difference cancellation torque Tcncl is a torque that acts in a direction to cancel the rotation difference ΔN1 and is set to a magnitude that does not cause the driver to feel uncomfortable. Note that "when the absolute value of the steering angle φste is less than the steering angle determination value φste_jdg" and "configured to cause the motor generator 50 to output the rotation difference cancellation torque Tcncl" correspond to "when a predetermined condition is met" and "configured to control the rotation of the motor generator in accordance with a predetermined condition" in this invention, respectively.

[0021] When the absolute value of the differential rotation ΔN1 exceeds the differential rotation determination value ΔN1_jdg (>0), the electronic control device 90 is configured to output a differential rotation limit torque Tlmt [N·m] from the motor generator 50 to suppress a decrease in durability of the vehicle powertrain 20. The differential rotation ΔN1 is equal to the differential rotation ΔN2 (=NwR-Nd) of the right wheel speed NwR relative to the differential case rotation speed Nd. When the absolute value of the differential rotation ΔN1 exceeds the differential rotation determination value ΔN1_jdg, the pair of left and right wheels 14 of the vehicle 10 are making a large left or right turn. The "differential rotation determination value ΔN1_jdg" is a predetermined determination value determined experimentally or by design, for example, based on the assumption that the crossing angle of the joint portion of the constant velocity joint provided on the pair of left and right axles 42 of the vehicle powertrain 20 may become too large, potentially reducing its durability. The "differential rotation limiting torque Tlmt" is a torque that acts in a direction that reduces the differential rotation ΔN1, and has a magnitude that is determined in advance experimentally or by design so as not to reduce the durability of the vehicle power transmission device 20. Note that "when the absolute value of the differential rotation ΔN1 exceeds the differential rotation determination value ΔN1_jdg" and "configured to output the differential rotation limiting torque Tlmt from the motor generator 50" correspond to "when a predetermined condition is met" and "configured to control the rotation of the motor generator in accordance with the predetermined condition" in the present invention, respectively.

[0022] The electronic control device 90 is configured to output a backlash-reducing torque Tgata [N·m] from the motor-generator 50 to reduce backlash G between the stator 52 and the rotor 54 when the absolute value of the differential rotation speed ΔN1 is equal to or less than the differential rotation speed determination value ΔN1_jdg and the vehicle 10 is in either a predetermined acceleration state in which the accelerator pedal is depressed immediately after decelerating, or a predetermined deceleration state in which the brakes are depressed immediately after accelerating. The "backlash-reducing torque Tgata" is a converted torque value obtained by converting the torque required to reduce backlash G into a torque value for the motor-generator 50, and is a predetermined torque determined experimentally or by design. The backlash G will be described later. "Accelerator-on" refers to, for example, depressing the accelerator pedal, thereby causing the accelerator opening θacc to become a positive value. "Brake-on" refers to, for example, depressing the brake pedal, thereby causing the brake operation amount θbrk to become a positive value. Note that "when the absolute value of the differential rotation ΔN1 is equal to or less than the differential rotation determination value ΔN1_jdg and in either a predetermined acceleration operation state or a predetermined deceleration operation state" corresponds to "when a predetermined condition is met" in the present invention. Also, "configured to output backlash-eliminating torque Tgata from motor-generator 50" corresponds to "configured to control the rotation of the motor-generator in accordance with a predetermined condition" in the present invention.

[0023] The electronic control device 90 is configured to cause the motor generator 50 to generate electricity through regeneration based on the differential rotation ΔN1 when the absolute value of the differential rotation ΔN1 is equal to or less than the differential rotation determination value ΔN1_jdg and the vehicle is neither in a predetermined acceleration state nor in a predetermined deceleration state. Note that "when the absolute value of the differential rotation ΔN1 is equal to or less than the differential rotation determination value ΔN1_jdg and the vehicle is neither in a predetermined acceleration state nor in a predetermined deceleration state" and "configured to cause the motor generator 50 to generate electricity through regeneration based on the differential rotation ΔN1" correspond to "when a predetermined condition is met" and "configured to control the rotation of the motor generator in accordance with a predetermined condition" in this invention, respectively. In this way, by causing the motor generator 50 to generate electricity through regeneration while the vehicle 10 is turning, the energy efficiency of the driving power source of the vehicle 10 (fuel efficiency of the internal combustion engine and power efficiency of the driving electric motor) is improved.

[0024] Fig. 2 is an example of a flowchart illustrating the main control operations of the electronic control unit 90 shown in Fig. 1. The flowchart in Fig. 2 is repeatedly executed while the vehicle is running.

[0025] First, in step S10 (hereinafter, step will be omitted), it is determined whether the absolute value of the steering angle φste is less than the steering angle determination value φste_jdg. If the determination in S10 is YES, in S20, a differential rotation resolution torque Tcncl is output from the motor generator 50. If the determination in S10 is NO, in S30, it is determined whether the absolute value of the differential rotation ΔN1 exceeds the differential rotation determination value ΔN1_jdg. If the determination in S30 is YES, in S40, a differential rotation limiting torque Tlmt is output from the motor generator 50. After S20 is executed or if the determination in S30 is NO, in both cases, it is determined in S50 whether a predetermined acceleration operation state is being performed. If the determination in S50 is NO, in S60, it is determined whether a predetermined deceleration operation state is being performed. In both cases, if the determination in S50 is YES or if the determination in S60 is YES, a backlash elimination torque Tgata is output from the motor generator 50 in S70. If the determination in S60 is NO, in S80, the motor generator 50 generates electricity by regeneration based on the differential rotation speed ΔN1, and the generated electricity is used to charge the battery 62. After execution of S40, S70, and S80, the process returns.

[0026] 3 is a diagram illustrating the control of the state of backlash G in S70 when the determination in S50 shown in FIG. 2 is YES. Between the differential case 32 and the right axle 42R, there is backlash G3 between the pair of differential pinions 36 and the pair of side gears 38 in the differential gear 30. There is backlash G1 in the spline fitting portion connecting the differential case 32 and the stator 52. There is backlash G2 in the spline fitting portion connecting the right axle 42R and the rotor 54. Thus, the backlash G between the stator 52 and the rotor 54 includes these backlashes G1, G2, and G3.

[0027] As shown in FIG. 3(a), when the vehicle 10 is decelerating and the motor-generator 50 is not driven, the stator 52, the rotor 54, and the right-wheel axle 42R rotate as if dragged by the differential case 32 as the differential case 32 decelerates. As a result, the backlashes G1, G2, and G3 are each eliminated to one side. As shown in FIG. 3(b), during a predetermined acceleration operation, a backlash elimination torque Tgata is output from the motor-generator 50. As a result, the backlash elimination of the backlash G2 is first shifted from one side to the other, as indicated by the dashed line, and then the backlash elimination of the backlash G3 is shifted from one side to the other, as indicated by the dashed-dotted line. Note that the backlash G1 is maintained at one side due to the reaction of the backlash elimination torque Tgata. The backlash elimination torque Tgata is output after the accelerator is pressed and before the vehicle 10 actually accelerates. As shown in Figure 3(c), when the vehicle 10 accelerates immediately after deceleration, the stator 52, rotor 54, and right wheel axle 42R rotate as if being dragged by the differential case 32 as the differential case 32 accelerates. In this state, the backlash G1 is eliminated to one side, and the backlashes G2 and G3 are eliminated to the other side. This suppresses rattle noise (e.g., the sound of teeth hitting each other) that occurs when the backlash G is reversed from one side to the other or from the other side to one side.

[0028] FIG. 4 is a diagram for explaining the control of the state of backlash G in S70 when the determination in S60 shown in FIG. 2 is YES.

[0029] As shown in FIG. 4(a), when the vehicle 10 is accelerating and the motor-generator 50 is not driven, the stator 52, the rotor 54, and the right-wheel axle 42R rotate as if being dragged by the differential case 32 as the differential case 32 accelerates. As a result, the backlashes G1, G2, and G3 are each eliminated to the other side. As shown in FIG. 4(b), in a predetermined deceleration operation state, a backlash elimination torque Tgata is output from the motor-generator 50. As a result, as shown by the dashed-dotted line, the backlash G1 is shifted to one side due to the reaction of the backlash elimination torque Tgata. Note that the backlashes G2 and G3 are maintained at the other side. The backlash elimination torque Tgata is output after the brake-on operation and before the vehicle 10 actually decelerates thereafter. As shown in Figure 4(c), when the vehicle 10 decelerates immediately after accelerating, the stator 52, rotor 54, and right wheel axle 42R rotate as if being dragged by the differential case 32 as the differential case 32 decelerates. In this state, the backlash G1 is eliminated on one side, and the backlashes G2 and G3 are eliminated on the other side. This suppresses rattle noise.

[0030] As shown in FIGS. 3 and 4, the backlash-reducing torque Tgata is a torque that acts in a direction in which the backlash G1 is reduced to one side and the backlash G2 and G3 are reduced to the other side.

[0031] According to this embodiment, (a) a ratio α1 of the right wheel speed NwR to the differential case rotation speed Nd is equal to a ratio α2 of the rotor rotation speed Nr to the stator rotation speed Ns, (b) the stator 52 has a coil 52c, (c) the rotor 54 generates a rotating magnetic field for the stator 52 in accordance with the relative rotation between the stator 52 and the rotor 54, and (d) the electronic control device 90 is configured to control the rotation of the motor-generator 50 in accordance with a predetermined condition when the predetermined condition is met. In this manner, a ratio α1 of the right wheel speed NwR to the differential case rotation speed Nd is equal to a ratio α2 of the rotor rotation speed Nr to the stator rotation speed Ns in the motor-generator 50. Furthermore, in the motor-generator 50, the stator 52 has a coil 52c, and the rotor 54 generates a rotating magnetic field in accordance with the relative rotation. Furthermore, the electronic control device 90 controls the rotation of the motor-generator 50 in accordance with a predetermined condition, thereby controlling the differential between the pair of left and right wheels 14. The right wheel axle 42R is provided with such a motor-generator 50. On the other hand, the left wheel axle 42L may not be provided with such a motor-generator 50. This makes it possible to reduce the number of motor-generators 50 mounted on the vehicle 10, thereby suppressing an increase in vehicle weight and enabling differential control of the pair of left and right wheels 14.

[0032] According to this embodiment, (a) the first axis C1 and the axis Cmg1 are a common rotation axis, and (b) the differential case 32 is connected to the stator 52 so as not to rotate relative to each other, and the right wheel axle 42R is connected to the rotor 54 so as not to rotate relative to each other. This causes the ratio α1 and the ratio α2 to have the same value. [Example]

[0033] 5 is a diagram illustrating the configuration of a vehicle power transmission device 120 according to a second embodiment. The vehicle power transmission device 120 is mounted on a vehicle 110. The vehicle power transmission device 120 according to the second embodiment has substantially the same configuration as the vehicle power transmission device 20 according to the first embodiment described above, but differs mainly in that a motor generator 150 is provided instead of the motor generator 50, a differential gear 130 is provided instead of the differential gear 30, and a right wheel axle 142R is provided instead of the right wheel axle 42R. Therefore, the following description will focus on the differences from the first embodiment, and descriptions of substantially common parts will be omitted as appropriate.

[0034] The axis Cmg2, which is the rotation axis of the motor generator 150, is parallel to the first axis C1. The axis Cmg2 corresponds to the "second axis" in the present invention. The configuration of the motor generator 150 itself is substantially the same as the configuration of the motor generator 50, except that a stator 152 and a rotor 154 are provided instead of the stator 52 and the rotor 54, respectively. A gear 152g is provided in the stator 152 so as not to rotate relative to the rotor 154, and a gear 154g is provided in the rotor 154 so as not to rotate relative to the rotor 154. The gears 152g and 154g have the same rotation radius. The differential gear 130 has substantially the same configuration as the differential gear 30, except that a differential case 132 is provided instead of the differential case 32. The differential case 132 is provided with a gear 132g fixed to the differential case 132 so as not to rotate relative to the rotor 154. The right axle 142R has substantially the same configuration as the right axle 42R, except that a gear 142Rg is provided on the right axle 142R so as not to rotate relative to the right axle 142R. The gear 132g and the gear 142Rg have the same turning radius.

[0035] The gears 132g and 152g mesh with each other, and the gears 142Rg and 154g mesh with each other. That is, the rotation of the differential case 132 is transmitted to the stator 152 via the gears 132g and 152g, and the rotation of the right wheel axle 142R is transmitted to the rotor 154 via the gears 142Rg and 154g. In this way, the method of connecting the motor generator 150 to the differential case 132 and the right wheel axle 142R is different from that of the first embodiment.

[0036] In this way, the ratio α1 of the right wheel speed NwR to the differential case rotation speed Nd is the same as the ratio α2 of the rotor rotation speed Nr to the stator rotation speed Ns. The gears 132g and 152g correspond to the "first gear pair" in this invention, and the gears 142Rg and 154g correspond to the "second gear pair" in this invention.

[0037] For example, in this embodiment, the ratio β (=ΔN1 / ΔN2) of the differential rotation ΔN1 of the rotor rotation speed Nr relative to the stator rotation speed Ns to the differential rotation ΔN2 of the right wheel speed NwR relative to the differential case rotation speed Nd can be made larger than "1". To achieve this ratio β, the gear ratio (tooth ratio) of gear 152g relative to gear 132g and the gear ratio of gear 154g relative to gear 142Rg can each be set to a value less than "1". The differential rotation ΔN1 corresponds to the "differential rotation of the rotation speed of the second rotating element relative to the rotation speed of the first rotating element" in this invention. The differential rotation ΔN2 corresponds to the "differential rotation of the rotation speed of the axle relative to the rotation speed of the differential case" in this invention.

[0038] In this embodiment, similarly to the above-described first embodiment, (a) the ratio α1 and the ratio α2 are the same, (b) the stator 152 has a coil 52c, (c) the rotor 154 generates a rotating magnetic field for the stator 152 in accordance with the relative rotation between the stator 152 and the rotor 154, and (d) the electronic control device 90 is configured to control the rotation of the motor generator 150 in accordance with the predetermined conditions when the predetermined conditions are met. By having the same configuration as the above-described first embodiment, the same effects as those of the first embodiment can be achieved based on the configuration.

[0039] In this embodiment, unlike the first embodiment, the axis Cmg2, which is the rotation axis of the motor generator 150, is different from the first axis C1. That is, the motor generator 150 is disposed on a rotation axis different from that of the right wheel axle 142R. This improves the degree of freedom in designing the position where the motor generator 150 is disposed.

[0040] In this embodiment, unlike the first embodiment, for example, the ratio β between the differential rotation speed ΔN1 and the differential rotation speed ΔN2 is greater than 1. In this embodiment, the amount of power generated by the motor generator 150 can be increased, for example, compared to when the ratio β is 1. [Example]

[0041] 6 is a diagram illustrating the configuration of a vehicle power transmission device 220 according to a third embodiment. The vehicle power transmission device 220 is mounted on a vehicle 210. The vehicle power transmission device 220 according to the third embodiment has substantially the same configuration as the vehicle power transmission device 120 according to the second embodiment described above, but differs mainly in that it includes a first relay gear 264 and a second relay gear 266 that are rotatable about a third axis C3. Therefore, the following description will focus on the parts that are different from the second embodiment, and descriptions of parts that are essentially the same will be omitted as appropriate.

[0042] The third axis C3, which is the rotation axis of the first relay gear 264 and the second relay gear 266, is parallel to the first axis C1 and the axis Cmg2. The first relay gear 264 and the second relay gear 266 are rotatable relative to each other. The first relay gear 264 and the second relay gear 266 have the same rotation radius. The first relay gear 264 meshes with both the gear 132g and the gear 152g. The second relay gear 266 meshes with both the gear 142Rg and the gear 154g. In this way, the differential case 132 and the stator 152 are connected via the first relay gear 264, and the right wheel axle 142R and the rotor 154 are connected via the second relay gear 266. The ratio α1 of the right wheel speed NwR to the differential case rotation speed Nd and the ratio α2 of the rotor rotation speed Nr to the stator rotation speed Ns are set to be the same.

[0043] For example, in this embodiment, the ratio β between the differential rotation ΔN1 and the differential rotation ΔN2 can be set to be greater than 1. The gear ratios among the gear 132g, the first relay gear 264, and the gear 152g, and the gear ratios among the gear 142Rg, the second relay gear 266, and the gear 154g can be set so as to achieve this ratio β.

[0044] This embodiment has the same configuration as the second embodiment described above, and therefore has the same effects as the second embodiment based on that configuration.

[0045] In this embodiment, unlike the second embodiment described above, the rotation of the differential case 132 and the right wheel axle 142R is transmitted to the motor generator 150 via a first relay gear 264 and a second relay gear 266, which are rotatable about the third axis C3. This provides greater design freedom in terms of the position at which the motor generator 150 is disposed than in the second embodiment. [Example]

[0046] 7 is a diagram illustrating the configuration of a vehicle power transmission device 320 according to a fourth embodiment. The vehicle power transmission device 320 is mounted on a vehicle 310. The vehicle power transmission device 320 according to the fourth embodiment has substantially the same configuration as the vehicle power transmission device 20 according to the first embodiment described above, but differs mainly in that it includes a plurality of motor generators 350 instead of the motor generator 50, a planetary gear unit 360, and a right wheel axle 342R instead of the right wheel axle 42R. Therefore, the following description will focus on the differences from the first embodiment, and descriptions of substantially common parts will be omitted as appropriate.

[0047] The planetary gear set 360 is a planetary gear set having a ring gear R, a sun gear S, a pinion P meshing with the ring gear R and the sun gear S, and a carrier CA that supports the pinion P so that it can rotate and revolve about its axis. The ring gear R is connected to the differential case 32 so as not to rotate relative to it, and the sun gear S is connected to the right wheel axle 342R so as not to rotate relative to it. The carrier CA is rotatable about the first axis C1, and supports the pinions P so that they can rotate about their own pinion rotation axes Cp and revolve about the first axis C1.

[0048] The rotation of the differential case 32 and the rotation of the right-wheel axle 342R are transmitted to each of the motor generators 350. Each of the motor generators 350 includes a rotor 354 non-rotatably connected to the pinion P and a stator 352 non-rotatably connected to the carrier CA. The pinion rotation axis Cp corresponds to the "second axis" in this invention. The rotor 354 is a rotating element that can rotate about the pinion rotation axis Cp and revolve about the first axis C1. The stator 352 is a rotating element that cannot rotate about the pinion rotation axis Cp and revolve about the first axis C1. In this way, the stator 352 and the rotor 354 are rotatable relative to each other about the pinion rotation axis Cp. The rotor 354 includes a cylindrical rotor core and a permanent magnet 354m attached to the outer peripheral surface of the rotor core. The stator 352 has a cylindrical stator core and a coil 352c wound around a groove formed in the inner periphery of the stator core. The ratio α1 of the right wheel speed NwR to the differential case rotation speed Nd is the same as the ratio α2 of the rotor rotation speed Nr to the stator rotation speed Ns.

[0049] The inverter 60 and the coil 352c of the motor generator 350 are electrically connected via a slip ring 58. For example, an annular electric circuit is provided on the outer circumferential surface of the carrier CA, and a brush in contact with the electric circuit is electrically connected to the inverter 60.

[0050] For example, when the vehicle 310 is moving forward in a straight line and the differential rotation ΔN2 is zero, the ring gear R and the sun gear S rotate at the same rotational speed. In this case, each pinion P revolves but does not rotate. Therefore, the rotors 354 connected to each pinion P and the stator 352 connected to the carrier CA only revolve. In other words, no relative rotation occurs between the stator 352 and the rotor 354 about the pinion rotation axis Cp. For example, when the vehicle 310 is turning in the forward direction and the differential rotation ΔN2 is not zero, the ring gear R and the sun gear S rotate at different rotational speeds. In this case, each pinion P revolves and rotates. Therefore, relative rotation occurs between the stator 352 and the rotor 354 about the pinion rotation axis Cp.

[0051] For example, in this embodiment, the ratio β between the differential rotation ΔN1 and the differential rotation ΔN2 can be made larger than 1. The gear ratio of the planetary gear device 360 ​​can be set so as to achieve this ratio β.

[0052] This embodiment has the same configuration as the first embodiment described above, and therefore has the same effects as the first embodiment based on that configuration.

[0053] Unlike the first embodiment, this embodiment can be provided with a plurality of motor generators 350. Furthermore, the outer diameter of the motor generator 350 (= the outer diameter relative to the pinion rotation axis Cp) can be reduced regardless of the outer diameter of the right wheel axle 342R.

[0054] In this embodiment, unlike the above-described first embodiment, for example, the ratio β is greater than 1. In such an embodiment, the amount of power generated by the motor generator 350 can be increased, for example, compared to when the ratio β is 1.

[0055] The above-described embodiments of the present invention are merely illustrative, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0056] In the above-described first to fourth embodiments, the backlash G between the stator 52, 152, 352 and the rotor 54, 154, 354 includes backlash G1, G2, and G3, but these are merely examples. For example, in the first embodiment, if the differential case 32 and the stator 52 are connected together by an interference fit or the like so that no backlash occurs, the backlash G does not include backlash G1. For example, the backlash G may include backlashes other than G1, G2, and G3.

[0057] In the above-described first to fourth embodiments, the backlash-reducing torque Tgata is a torque acting in a direction in which the backlash G1 is reduced to one side and the backlashes G2 and G3 are reduced to the other side, but it may also be a torque acting in the opposite direction. Even in this embodiment, in either a predetermined deceleration operation state or a predetermined acceleration operation state, the backlash G1 is reduced to the other side and the backlashes G2 and G3 are reduced to one side. This suppresses rattle noise even when the vehicle is subsequently accelerated or decelerated.

[0058] In the third embodiment described above, the gears 132g and 142Rg, the first relay gear 264 and the second relay gear 266, and the gears 152g and 154g all have the same rotation radius, but the present invention is not limited to this. For example, as long as the ratio α1 and the ratio α2 are the same, the aforementioned gears may each have a different rotation radius.

[0059] In the above-described fourth embodiment, the motor generator 350 is provided for each of the multiple pinions P of the planetary gear set 360, but the present invention is not limited to this. The present invention may be provided in any embodiment in which the motor generator 350 is provided for at least one of the multiple pinions P of the planetary gear set 360.

[0060] In the above-described first to fourth embodiments, the rotors 54, 154, and 354 have permanent magnets attached to the outer periphery of their rotor cores. However, this is not limiting. For example, the rotors 54, 154, and 354 may have permanent magnets embedded in the outer periphery of their rotor cores. For example, the rotors 54, 154, and 354 may generate a magnetic field by supplying a direct current to coils wound around their rotor cores via slip rings, and generate a rotating magnetic field in response to relative rotation with respect to the stators 52, 152, and 352.

[0061] In the above-described first to fourth embodiments, the stators 52, 152, 352 are the first rotating elements and the rotors 54, 154, 354 are the second rotating elements, but the stators 52, 152, 352 may be the second rotating elements and the rotors 54, 154, 354 may be the first rotating elements.

[0062] In the above-described first to fourth embodiments, the right axle 42R, 142R, 342R is connected to the motor generators 50, 150, 350, respectively, but the left axle 42L may be connected to the motor generators 50, 150, 350, respectively, instead of the right axle 42R, 142R, 342R. In this case, the "left axle 42L" corresponds to the "axle connecting the differential gear and one of the pair of left and right wheels" in the present invention. [Explanation of symbols]

[0063] 14: Pair of left and right wheels, 20, 120, 220, 320: Vehicle power transmission device, 30, 130: Differential gear, 32, 132: Differential case, 42R, 142R, 342R: Right wheel axle (axle connecting the differential gear and one of the pair of left and right wheels), 50, 150, 350: Motor generator, 52, 152, 352: Stator (1st rotating element, one of the first rotating element and the second rotating element), 52c, 352c: coil, 54, 154, 354: rotor (second rotating element, the other of the first rotating element and the second rotating element), 90: electronic control device (control device), 132g: gear (first gear pair), 142Rg: gear (second gear pair), 152g: gear (first gear pair), 154g: gear (second gear pair), 264: first relay gear, 26 6: second relay gear, 360: planetary gear device, C1: first axis, Cmg1, Cmg2: axis (second axis), C3: third axis, CA: carrier, Nd: differential case rotation speed (rotation speed of differential case), Cp: pinion rotation axis (second axis), Nr: rotor rotation speed (rotation speed of second rotating element), Ns: stator rotation speed (rotation speed of first rotating element), NwR: right wheel speed (axle rotational speed), P: Pinion, R: Ring gear, S: Sun gear, α1: Ratio (ratio of the rotational speed of the axle to the rotational speed of the differential case), α2: Ratio (ratio of the rotational speed of the second rotating element to the rotational speed of the first rotating element), ΔN1: Differential rotation (differential rotation of the rotational speed of the second rotating element to the rotational speed of the first rotating element), ΔN2: Differential rotation (differential rotation of the rotational speed of the axle to the rotational speed of the differential case)

Claims

1. a differential gear rotatable about a first axis; an axle connecting the differential gear to one of a pair of left and right wheels; a motor generator having a first rotating element and a second rotating element that are rotatable relative to each other about a second axis; a control device that controls the rotation of the motor generator, The ratio of the rotational speed of the axle to the rotational speed of the differential case of the differential gear and the ratio of the rotational speed of the second rotating element to the rotational speed of the first rotating element are set to be the same, one of the first rotating element and the second rotating element has a coil; the other of the first rotating element and the second rotating element generates a rotating magnetic field for one of the first rotating element and the second rotating element in response to relative rotation between the first rotating element and the second rotating element, The control device is configured to control the rotation of the motor generator in accordance with a predetermined condition when the predetermined condition is met. A power transmission device for a vehicle.

2. the first axis and the second axis are a common rotation axis, The differential case is connected to the first rotating element so as not to rotate relative to the first rotating element, and the axle is connected to the second rotating element so as not to rotate relative to the second rotating element.

2. The power transmission device for a vehicle according to claim 1.

3. the first axis and the second axis are parallel to each other, The differential case and the first rotating element are connected via a first gear pair, The axle and the second rotating element are connected via a second gear pair.

2. The power transmission device for a vehicle according to claim 1.

4. The differential case and the first rotating element are connected via a first relay gear provided on a third axis parallel to the first axis and the second axis, The axle and the second rotating element are connected via a second relay gear provided on the third axis.

4. The power transmission device for a vehicle according to claim 3.

5. a planetary gear device including a ring gear non-rotatably connected to the differential case, a sun gear non-rotatably connected to the axle, a pinion meshing with the ring gear and the sun gear, and a carrier supporting the pinion so that it can rotate and revolve; The carrier is connected to the first rotating element, and the pinion is connected to the second rotating element.

2. The power transmission device for a vehicle according to claim 1.

6. The differential rotation of the second rotating element relative to the rotation speed of the first rotating element is made larger than the differential rotation of the axle relative to the rotation speed of the differential case.

6. A power transmission device for a vehicle according to claim 1, 3, 4 or 5.

Images