Vehicle

Abstract

To reduce driving loss.SOLUTION: A vehicle according to the present invention comprises: a connection part for connecting a trailer; and a differential rotation generating mechanism for generating a differential rotation at front and rear wheels when a tongue weight equal to or larger than a predetermined value is imparted to the connection part.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to the technical field of vehicles. [Background technology]

[0002] Conventionally, vehicles capable of towing trailers have been proposed. As described in Patent Document 1, such vehicles have a hitch ball attached as a coupling part to the lower rear part of the vehicle body, and a trailer is coupled to the vehicle by fitting a hitch coupler arranged at the tip of the trailer into the hitch ball. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-44029 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned vehicle, part of the trailer's weight (load) is added to the coupling as a tongue weight. Therefore, the rear wheels of the vehicle are crushed by the tongue weight, and the dynamic radius (the distance from the center to the ground) becomes smaller. This may increase the driving loss of the vehicle.

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to reduce driving loss. [Means for solving the problem]

[0006] A vehicle according to one embodiment of the present invention includes a coupling portion for coupling a trailer, and a differential rotation generating mechanism that generates differential rotation between the front and rear wheels when a tongue weight of a predetermined value or greater is added to the coupling portion. Effect of the Invention

[0007] According to the present invention, the driving loss can be reduced. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a configuration of a vehicle system. [Diagram 2] FIG. 2 is an enlarged view of the dashed line portion in FIG. 1, illustrating the configuration of a connecting mechanism. [Diagram 3] FIG. 2 is an enlarged view of the dashed line portion in FIG. 1, illustrating the configuration of a connecting mechanism. [Figure 4] FIG. 2 is a diagram showing a configuration of an on / off valve. [Diagram 5] FIG. 2 is a diagram showing a configuration of an on / off valve. [Figure 6] FIG. 2 is a diagram showing a configuration of a power transmission path of a vehicle. [Figure 7] FIG. 4 is a diagram showing the state of each part for each mode. [Figure 8] FIG. 4 is a diagram showing a power transmission path in a normal driving mode. [Figure 9] FIG. 4 is a diagram showing a power transmission path in a towing travel mode. [Figure 10] FIG. 4 is a diagram showing a power transmission path in a power storage mode. [Figure 11] FIG. 4 is a diagram showing a power transmission path in a power retention mode. [Figure 12] FIG. 4 is a diagram showing a power transmission path in a power release mode. [Figure 13] 4 is a flowchart showing a flow of control by an ECU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <1. Vehicle system configuration> 1 is a diagram showing a configuration of a vehicle system 1. As shown in FIG. The vehicle 2 has a motor generator 51 (see FIG. 6) as a power source and can run independently. The vehicle 2 may have an engine as a power source. The trailer 3 does not have a power source and cannot run on its own.

[0010] The vehicle 2 and the trailer 3 are connected via a connecting mechanism 4, which enables the vehicle 2 to tow the trailer 3.

[0011] As shown in FIGS. 2 and 3, the connecting mechanism 4 includes a vehicle side connecting portion 10 and a trailer side connecting portion 20. As shown in FIG.

[0012] The vehicle side connecting portion 10 is provided on a rear lower portion of the vehicle body 5. The vehicle side connecting portion 10 includes a hitch member 11, a support portion 12, a lever 13, a hitch pin 14, a hitch ball 15, and a pressure generating portion 30.

[0013] The hitch member 11 is fixed to the rear lower part of the vehicle body 5. The support part 12 is fixed to the lower part of the hitch member 11, and has a through hole penetrating in the vehicle width direction of the vehicle 2. In the following, the vehicle width direction of the vehicle 2 will be simply referred to as the vehicle width direction.

[0014] The lever 13 is a generally rectangular columnar member disposed along the front-rear direction of the vehicle 2, and is provided with an attachment portion 13a protruding upward near the center. A through hole penetrating in the vehicle width direction is formed in the attachment portion 13a.

[0015] The hitch pin 14 is inserted into both a through hole formed in the support part 12 and a through hole formed in the mounting part 13a and is prevented from slipping out of these through holes. As a result, the lever 13 is supported by the support part 12 so as to be rotatable about the hitch pin 14 as a rotation axis.

[0016] A roughly spherical hitch ball 15 is attached to the upper surface of the rear end of the lever 13. Furthermore, a hydraulic piston 32 of a pressure generating section 30 is attached to the upper surface of the front end of the lever 13 . Therefore, the hitch ball 15 and the hydraulic piston 32 are attached to the opposite sides of the lever 13 with the hitch pin 14 in between.

[0017] The pressure generating unit 30 includes a hydraulic cylinder 31 and a hydraulic piston 32. The hydraulic cylinder 31 contains oil 34 therein, and the hydraulic piston 32 is disposed so as to be slidable in the vertical direction.

[0018] The hydraulic piston 32 has a head portion disposed within the hydraulic cylinder 31, and a shaft portion connected to the lever 13. Therefore, the hydraulic piston 32 slides up and down within the hydraulic cylinder 31 in accordance with the rotational movement of the lever 13.

[0019] An oil flow path 33 is connected to the hydraulic cylinder 31 above the position of the head portion when the hydraulic piston 32 moves most upward. The oil flow path 33 is formed by, for example, a pipe or a hose. One end of the oil flow path 33 is connected to the hydraulic cylinder 31, and the other end is connected to an on-off valve 40, which will be described later.

[0020] The trailer side connecting portion 20 includes an arm portion 21 and a hitch coupler 22. The arm portion 21 is fixed to the front lower portion of the trailer 3, and is a substantially prismatic member disposed so as to protrude forward.

[0021] A cup-shaped hitch coupler 22 is attached to the underside of the front end of the arm portion 21. The hitch coupler 22 is formed so that the hitch ball 15 can be engaged therewith.

[0022] In the coupling mechanism 4, when the trailer 3 is coupled to the vehicle 2, the hitch coupler 22 is engaged with the hitch ball 15 by the user. At this time, as shown by the white arrow in Figure 3, part of the weight of the trailer 3 is added as a tongue weight to the hitch ball 15 of the vehicle-side coupling part 10. This causes the lever 13 to rotate around the hitch pin 14 so that the rear side (the hitch ball 15 side) moves downward (clockwise in Figure 3).

[0023] Then, the front side (the pressure generating unit 30 side) of the lever 13 moves upward. At this time, the lever 13 moves the hydraulic piston 32 upward. In the pressure generating unit 30, as a result of the hydraulic piston 32 being moved upward, the oil 34 contained in the hydraulic cylinder 31 is pushed out into the oil flow path 33, as indicated by the solid black arrow in Fig. 3. That is, the pressure generating unit 30 generates hydraulic pressure toward the oil flow path 33.

[0024] Figures 4 and 5 are diagrams showing the configuration of the on-off valve 40. Figure 4 is a diagram showing the on-off valve 40 when no hydraulic pressure is supplied. Figure 5 is a diagram showing the on-off valve 40 when hydraulic pressure is supplied.

[0025] As shown in FIGS. 4 and 5, the on / off valve 40 includes a body 41, a spool 42, and an elastic member 43.

[0026] The body 41 is formed in a hollow cylindrical shape with both ends closed. The spool 42 is formed in a cylindrical shape and is housed within the body 41.

[0027] The spool 42 includes a connecting rod 42a, a first land 42b, and a second land 42c. The diameter of the connecting rod 42a is sufficiently smaller than the inner diameter of the body 41. In addition, the length of the connecting rod 42a in the central axis direction is shorter than the length inside the body 41.

[0028] A first land 42b and a second land 42c are fixed to the connecting rod 42a and spaced apart in the central axis direction. The first land 42b and the second land 42c are formed to have a diameter such that the oil 34 does not flow in the central axis direction between the outer surfaces of the first land 42b and the second land 42c and the inner surface of the body 41.

[0029] A pilot chamber 42d is formed in the body 41, with which an end face of the first land 42b opposite to the second land 42c comes into contact. Also, a spring chamber 42e is formed in the body 41, with which an end face of the second land 42c opposite to the first land 42b comes into contact.

[0030] The spring chamber 42e accommodates an elastic member 43, which may be a spring. One end of the elastic member 43 abuts against the second land 42c, and the other end of the elastic member 43 abuts against the inner surface of the spring chamber 42e. The elastic member 43 biases the spool 42 toward the pilot chamber 42d.

[0031] A first inlet port 41a, a second inlet port 41b, and a discharge port 41c are formed in the body 41 from the first land 42b side toward the second land 42c side. The first inlet port 41a, the second inlet port 41b, and the discharge port 41c penetrate the body 41 between the inner surface and the outer surface.

[0032] Further, grooves are formed in the inner surface of the body 41 in the circumferential direction at positions where the first inlet port 41a, the second inlet port 41b, and the outlet port 41c are formed.

[0033] The first inlet port 41a and the second inlet port 41b are connected to the oil flow passage 33. The discharge port 41c is connected to an oil flow passage 44.

[0034] When hydraulic pressure (oil 34) is not supplied from the pressure generating unit 30 to the on-off valve 40, the spool 42 is biased toward the pilot chamber 42d by the elastic member 43, and the second inlet port 41b is blocked by the second land 42c, as shown in Fig. 4. This state is referred to as the off state.

[0035] On the other hand, as shown in Fig. 5, when the trailer 3 is coupled to the vehicle 2 and hydraulic pressure (oil 34) is supplied from the pressure generating unit 30 to the on-off valve 40, the oil 34 flows into the pilot chamber 42d through the first inflow port 41a. Then, the body 41 is pushed toward the spring chamber 42e by the oil 34 entering the pilot chamber 42d.

[0036] When a weight of a predetermined value or more is applied from the trailer 3 to the vehicle-side coupling portion 10, the second land 42c moves further toward the spring chamber 42e, as shown in FIG. 5, and the blocked discharge port 41c is opened. As a result, the second inflow port 41b and the discharge port 41c communicate with each other, and the oil 34 passes through the discharge port 41c and flows into the oil flow passage 44. This state is referred to as the on state.

[0037] Fig. 6 is a diagram showing the configuration of a power transmission path of vehicle 2. As shown in Fig. 6, vehicle 2 is equipped with a motor generator 51 as a power source. Motor generator 51 is, for example, a three-phase AC motor, and is driven by power supplied from battery 80. Furthermore, when performing regenerative operation, motor generator 51 charges battery 80 by supplying the power generated by the regenerative operation to battery 80.

[0038] The motor generator 51 is connected to front wheels 53 via a front differential gear 52, and transmits power to the front wheels 53. A disconnect clutch 54 is provided between the front differential gear 52 and one of the front wheels 53.

[0039] The disconnect clutch 54 is controlled to be engaged and disengaged by an ECU (Electronic Control Unit) 81. When the disconnect clutch 54 is engaged, the power from the motor generator 51 is transmitted to the front wheels 53, causing the front wheels 53 to rotate. On the other hand, when the disconnect clutch 54 is disengaged, the power from the motor generator 51 is no longer transmitted to the front wheels 53.

[0040] Further, a first propeller shaft 55 is connected to the front differential gear 52. A transfer clutch 56 is provided midway on the first propeller shaft 55.

[0041] The transfer clutch 56 is controlled to be engaged and disengaged by the ECU 81. When the transfer clutch 56 is engaged, the power from the motor generator 51 is transmitted to the rear wheels 60. On the other hand, when the transfer clutch 56 is disengaged, the power from the motor generator 51 is not transmitted to the rear wheels 60.

[0042] Further, a differential rotation generating mechanism 57 is connected to the first propeller shaft 55 on the downstream side of the transfer clutch 56 (the opposite side to the motor generator 51).

[0043] The differential rotation generating mechanism 57 transmits the power from the motor generator 51 to a downstream energy storage mechanism 58. At this time, the differential rotation generating mechanism 57 can transmit the power while maintaining the rotation speed of the first propeller shaft 55 unchanged or by increasing the rotation speed.

[0044] The differential rotation generating mechanism 57 includes a ring gear 61 , a pinion gear 62 , a ring gear 63 , a speed-passing clutch 64 , a speed-increasing clutch 65 , a rotating case 66 , a fastening clutch 67 , a locking mechanism 68 , and a cover 69 .

[0045] The ring gear 61 is fixed to the first propeller shaft 55, and when the transfer clutch 56 is engaged, rotates at the same rotation speed as the first propeller shaft 55. The ring gear 61 has an internal gear and is meshed with a pinion gear 62.

[0046] The pinion gears 62 have external gears, and are arranged in plurality on the circumferential outer side of the first propeller shaft 55. The pinion gears 62 are supported rotatably (on their own axes) by a cover 69 that functions as a carrier. However, the pinion gears 62 are supported by the cover 69 so as not to revolve around the rotation axis of the first propeller shaft 55.

[0047] The pinion gear 62 also meshes with an internal gear of a ring gear 63. The ring gear 63 rotates coaxially with the first propeller shaft 55 and the ring gear 61.

[0048] The rotating case 66 is housed in a cover 69 so as to be rotatable concentrically with the first propeller shaft 55 and the ring gear 61. The rotating case 66 is connected to the ring gear 61 via a speed-transmitting clutch 64, and is connected to the ring gear 63 via a speed-increasing clutch 65.

[0049] The speed-passing clutch 64 is switched between engagement and disengagement by hydraulic pressure supplied from the pressure generating unit 30. The speed-passing clutch 64 is directly supplied with the oil 34 from the on / off valve 40 via the oil flow path 44. The through clutch 64 is engaged when hydraulic pressure is not supplied from the pressure generating unit 30, connecting the ring gear 61 and the rotating case 66 to rotate them at the same rotation speed. When hydraulic pressure is supplied from the pressure generating unit 30, the through clutch 64 is released to separate the ring gear 61 and the rotating case 66.

[0050] The speed-increasing clutch 65 is switched between engagement and disengagement by hydraulic pressure supplied from the pressure generating unit 30. The speed-increasing clutch 65 is supplied with oil 34 from the on / off valve 40 via the valve 45. The speed-increasing clutch 65 opens when hydraulic pressure is not supplied from the pressure generating unit 30, and separates the ring gear 63 and the rotating case 66. When hydraulic pressure is supplied from the pressure generating unit 30, the speed-increasing clutch 65 closes, and connects the ring gear 63 and the rotating case 66 to rotate at the same rotation speed.

[0051] Here, the gear group consisting of ring gear 61, pinion gear 62, and ring gear 63 has a gear ratio set so that the rotation speed of ring gear 63 is, for example, about 3% faster than the rotation speed of ring gear 61. Therefore, the gear group consisting of ring gear 61, pinion gear 62, and ring gear 63 rotates rotating case 66 at a higher rotation speed than first propeller shaft 55 when speed-up clutch 65 is engaged.

[0052] The opening and closing of the valve 45 is controlled by the ECU 81. When the valve 45 is opened, hydraulic pressure (oil 34) is supplied from the on-off valve 40 to the speed-increasing clutch 65. On the other hand, when the valve 45 is closed, hydraulic pressure is no longer supplied from the on-off valve 40 to the speed-increasing clutch 65.

[0053] A rotating shaft 72 of the energy storage mechanism 58 is connected to the rear end of the first propeller shaft 55 via an engagement clutch 67. The engagement and disengagement of the engagement clutch 67 is controlled by the ECU 81. When the engagement clutch 67 is engaged, the first propeller shaft 55 and the rotating shaft 72 are connected, and the rotating shaft 72 rotates at the same rotation speed as the first propeller shaft 55. On the other hand, when the fastening clutch 67 is released, the first propeller shaft 55 and the rotating shaft 72 are separated from each other, and the rotating shaft 72 becomes rotatable relative to the first propeller shaft 55 .

[0054] A lock mechanism 68 is provided between the rotary shaft 72 and the rotary case 66. The lock mechanism 68 is provided to be movable, for example, in the axial direction of the rotary case 66. The movement of the lock mechanism 68, i.e., the engagement and release of the lock mechanism 68, is controlled by an ECU 81. The lock mechanism 68, when moved toward the fastening clutch 67, connects (fastens) the rotating case 66 and the rotating shaft 72, causing the rotating case 66 and the rotating shaft 72 to rotate at the same rotation speed. In addition, the lock mechanism 68, when moved toward the rotating shaft 72, separates (releases) the rotating case 66 and the rotating shaft 72, allowing the rotating case 66 and the rotating shaft 72 to rotate relative to each other.

[0055] The energy storage mechanism 58 includes a second propeller shaft 71 , a rotating shaft 72 , a ball screw 73 , and an elastic member 74 .

[0056] The second propeller shaft 71 is connected to the rotating case 66 and rotates at the same rotation speed as the rotating case 66. In addition, the second propeller shaft 71 is connected to the rear wheels 60 via the rear differential gear 59 and transmits power to the rear wheels 60. The second propeller shaft 71 is formed in a cylindrical shape with a bottom having a bottom portion 71a on the rear side. Further, a screw groove is formed on the inner peripheral surface that defines the internal space of the second propeller shaft 71. A rotating shaft 72 is rotatably housed in the internal space of second propeller shaft 71 .

[0057] A ball screw 73 is splined to the outer circumferential surface of the rotating shaft 72. The balls of the ball screw 73 are fitted into a thread groove formed on the inner circumferential surface of the second propeller shaft 71. The ball screw 73 moves in the axial direction of the second propeller shaft 71 and the rotating shaft 72 as the second propeller shaft 71 and the rotating shaft 72 rotate relative to each other. Specifically, when second propeller shaft 71 rotates relatively faster than rotary shaft 72 (at a high rotation speed), ball screw 73 moves to the rear stage side (toward bottom portion 71a).

[0058] An elastic member 74 is housed between the ball screw 73 and the bottom portion 71a in the internal space of the second propeller shaft 71. The elastic member 74 is, for example, a spring, and assumes a natural length when the ball screw 73 moves to a position farthest from the bottom portion 71a.

[0059] When the second propeller shaft 71 rotates relatively faster than the rotary shaft 72 and the ball screw 73 moves to the bottom portion 71a, the elastic member 74 is contracted (compressed) by the ball screw 73. When the locking mechanism 68 connects the rotating case 66 and the rotating shaft 72, no differential rotation occurs between the second propeller shaft 71 and the rotating shaft 72, and the ball screw 73 is maintained in its current position. Furthermore, when the rotating shaft 72 becomes rotatable faster than the second propeller shaft 71, the elastic force of the elastic member 74 which tries to return to its original state moves the ball screw 73 toward the engaging clutch 67. When moving toward the engaging clutch 67, the ball screw 73 rotates the rotating shaft 72 at a relatively high rotation speed with respect to the second propeller shaft 71.

[0060] <2. Mode> Fig. 7 is a diagram showing the state of each part for each mode. Fig. 8 is a diagram showing the power transmission path in the normal driving mode. Note that in Figs. 8 to 12, the power transmission path is indicated by a thick line.

[0061] During normal driving mode in which the vehicle 2 is not towing the trailer 3, as shown in FIG. 7, no tongue weight is added to the vehicle side coupling portion 10 (tongue weight less than a predetermined value), and no hydraulic pressure is generated by the pressure generating portion 30. Therefore, the on / off valve 40 is in the off state, and hydraulic pressure is not supplied to the through clutch 64 and the accelerating clutch 65. Then, the through clutch 64 is engaged and the accelerating clutch 65 is disengaged. The ECU 81 also performs control so as to engage the disconnect clutch 54, engage the transfer clutch 56, disengage the engaging clutch 67, and disengage the lock mechanism 68.

[0062] 8, the power output from the motor generator 51 is transmitted to the front wheels 53 via the front differential gear 52. The power output from the motor generator 51 is also transmitted to the rear wheels 60 via the front differential gear 52, the first propeller shaft 55, the ring gear 61, the speed-passing clutch 64, the rotating case 66, the second propeller shaft 71, and the rear differential gear 59.

[0063] At this time, in the differential rotation generating mechanism 57, the ring gear 61 and the rotating case 66 are connected by the speed-passing clutch 64, so that no differential rotation occurs between the first propeller shaft 55 and the rotating case 66. In FIG. 7, the absence of differential rotation is indicated as "directly connected." Furthermore, since the rotating case 66 and the second propeller shaft 71 rotate at the same rotation speed, no differential rotation occurs between the first propeller shaft 55 and the second propeller shaft 71. Thus, in the vehicle 2, the front wheels 53 and the rear wheels 60 are rotated without generating differential rotation.

[0064] Fig. 9 is a diagram showing the power transmission path in the towing mode. In the towing mode, in which the trailer 3 is coupled to the vehicle 2 and a tongue weight of a predetermined value or more is applied to the vehicle-side coupling 10, as shown in Fig. 7, the pressure generating unit 30 generates hydraulic pressure that turns the on-off valve 40 to the on state. Therefore, the on / off valve 40 is turned on and hydraulic pressure is supplied to the through clutch 64 and the speed-up clutch 65. Then, the through clutch 64 is disengaged and the speed-up clutch 65 is engaged. The ECU 81 also performs control so as to engage the disconnect clutch 54, engage the transfer clutch 56, disengage the engaging clutch 67, and release the lock mechanism 68.

[0065] 9, the power output from the motor generator 51 is transmitted to the front wheels 53 via the front differential gear 52. The power output from the motor generator 51 is also transmitted to the rear wheels 60 via the front differential gear 52, the first propeller shaft 55, the ring gear 61, the pinion gear 62, the ring gear 63, the speed-increasing clutch 65, the rotating case 66, the second propeller shaft 71, and the rear differential gear 59.

[0066] At this time, in the differential rotation generating mechanism 57, the first propeller shaft 55 and the rotating case 66 are connected via the ring gear 61, the pinion gear 62, the ring gear 63, and the speed-increasing clutch 65. Therefore, due to the gear ratio of the ring gear 61, the pinion gear 62, and the ring gear 63, the rotating case 66 rotates faster than the first propeller shaft 55.

[0067] As a result, a differential rotation occurs between the first propeller shaft 55 and the rotating case 66, and the rotation speed of the rotating case 66 becomes higher (accelerated) than the rotation speed of the first propeller shaft 55. In addition, since the rotating case 66 and the second propeller shaft 71 rotate at the same rotation speed, a differential rotation also occurs between the first propeller shaft 55 and the second propeller shaft 71, and the rotation speed of the second propeller shaft 71 becomes higher (accelerated) than the rotation speed of the first propeller shaft 55. Thus, in the vehicle 2 , the rear wheels 60 rotate faster than the front wheels 53 .

[0068] Here, when a tongue weight is added to the vehicle side connecting portion 10, the rear wheel 60 is crushed by the tongue weight, and the moving radius becomes smaller. On the other hand, the rear wheels 60 are rotated faster than the front wheels 53 by the differential rotation generating mechanism 57. Therefore, these are offset, and it is possible to reduce the difference between the travel distance of the front wheels 53 and the travel distance of the rear wheels 60. As a result, in the vehicle 2, slippage of the rear wheels 60 when towing the trailer 3 can be reduced, and the drive loss due to the differential rotation of the transfer clutch 56 can be reduced.

[0069] Fig. 10 is a diagram showing the power transmission path in the power storage mode, and Fig. 10 shows the power transmission path when the vehicle 2 is coasting.

[0070] When the vehicle 2 is coasting or decelerating while being towed and travelling with the trailer 3 connected thereto, the motor generator 51 performs regenerative operation.

[0071] However, when the vehicle 2 tows the trailer 3, the amount of power generated during regenerative operation of the motor generator 51 increases by the weight of the trailer 3, and it is possible that there will be surplus power even when charging the battery 80. Also, in cold regions or the like, the temperature of the battery 80 will drop, which may result in an output limit (charging limit) being imposed on the battery 80, and it is possible that there will be surplus power even when the battery 80 is charged with power obtained through regenerative operation by the motor generator 51.

[0072] Furthermore, if the battery 80 is fully charged, the battery 80 cannot be charged even if regenerative driving is performed by the motor generator 51. Also, because the weight of the trailer 3 is added, regenerative driving alone during deceleration cannot decelerate the vehicle 2, so it is also possible to use the brakes in combination.

[0073] In such a case, the power generated by the motor generator 51 will be surplus, or braking will be used in combination, resulting in increased energy loss.

[0074] Therefore, the vehicle 2 is shifted to the power storage mode when a predetermined power storage condition is satisfied during towing. The power storage condition is, for example, when the vehicle 2 is coasting or decelerating. Note that the power storage condition may include a condition that, when the motor generator 51 generates power, there is surplus power even after charging the battery 80.

[0075] 7 and 10, in the power accumulation mode, similarly to the towing travel mode, hydraulic pressure is generated by the pressure generating unit 30, the on-off valve 40 is turned on, and hydraulic pressure is supplied to the speed-passing clutch 64 and the speed-up clutch 65. Then, the speed-passing clutch 64 is released, and the speed-up clutch 65 is engaged. Further, the ECU 81 performs control so as to engage the disconnect clutch 54, engage the transfer clutch 56, engage the engaging clutch 67, and release the lock mechanism 68. Thus, the power storage mode is different from the towing travel mode in that the engagement clutch 67 is engaged.

[0076] 10, for example, when the vehicle 2 is coasting, the power output from the motor generator 51 is transmitted to the front wheels 53 via the front differential gear 52. The power output from the motor generator 51 is also transmitted to the rear wheels 60 via the front differential gear 52, the first propeller shaft 55, the ring gear 61, the pinion gear 62, the ring gear 63, the speed-increasing clutch 65, the rotating case 66, the second propeller shaft 71, and the rear differential gear 59.

[0077] At this time, in the differential rotation generating mechanism 57, the first propeller shaft 55 and the rotating case 66 are connected via the ring gear 61, the pinion gear 62, the ring gear 63, and the speed-increasing clutch 65. Therefore, due to the gear ratio of the ring gear 61, the pinion gear 62, and the ring gear 63, the rotating case 66 rotates faster than the first propeller shaft 55.

[0078] As a result, a differential rotation occurs between the first propeller shaft 55 and the rotating case 66, and the rotation speed of the rotating case 66 becomes higher (accelerated) than the rotation speed of the first propeller shaft 55. In addition, since the rotating case 66 and the second propeller shaft 71 rotate at the same rotation speed, a differential rotation also occurs between the first propeller shaft 55 and the second propeller shaft 71, and the rotation speed of the second propeller shaft 71 becomes higher (accelerated) than the rotation speed of the first propeller shaft 55. Thus, in the vehicle 2 , the rear wheels 60 rotate faster than the front wheels 53 .

[0079] Further, the rotating shaft 72 is connected to the first propeller shaft 55 via the fastening clutch 67. Therefore, the second propeller shaft 71 rotates faster than the rotating shaft 72. When the second propeller shaft 71 rotates faster than the rotating shaft 72, the ball screw 73 is moved toward the bottom portion 71a and the elastic member 74 is contracted.

[0080] In this manner, contraction energy is stored in the elastic member 74 in the power storage mode.

[0081] Fig. 11 is a diagram showing the power transmission path in the power retention mode. In the vehicle 2, when contraction energy is stored in the elastic member 74 during towing, the vehicle transitions to the power retention mode when the power retention condition is satisfied. The power retention condition is that the elastic member 74 is contracted (the ball screw 73 is moved toward the bottom 71a) and the vehicle 2 ends coasting or deceleration. The contraction of the elastic member 74 can be determined, for example, by measuring the position of the ball screw 73 with a sensor or the like.

[0082] 7 and 11, in the power retention mode, similarly to the towing travel mode, hydraulic pressure is generated by the pressure generating unit 30, the on-off valve 40 is turned on, and hydraulic pressure is supplied to the speed-passing clutch 64 and the speed-up clutch 65. Then, the speed-passing clutch 64 is released, and the speed-up clutch 65 is engaged. Further, the ECU 81 performs control so as to engage the disconnect clutch 54, engage the transfer clutch 56, release the engaging clutch 67, and engage the lock mechanism 68. Thus, the power retention mode is different from the towing travel mode in that the lock mechanism 68 is engaged.

[0083] 11, the power output from the motor generator 51 is transmitted to the front wheels 53 via the front differential gear 52. The power output from the motor generator 51 is also transmitted to the rear wheels 60 via the front differential gear 52, the first propeller shaft 55, the ring gear 61, the pinion gear 62, the ring gear 63, the speed-increasing clutch 65, the rotating case 66, the second propeller shaft 71, and the rear differential gear 59.

[0084] At this time, in the differential rotation generating mechanism 57, the first propeller shaft 55 and the rotating case 66 are connected via the ring gear 61, the pinion gear 62, the ring gear 63, and the speed-increasing clutch 65. Therefore, due to the gear ratio of the ring gear 61, the pinion gear 62, and the ring gear 63, the rotating case 66 rotates faster than the first propeller shaft 55.

[0085] As a result, a differential rotation occurs between the first propeller shaft 55 and the rotating case 66, and the rotation speed of the rotating case 66 becomes higher (accelerated) than the rotation speed of the first propeller shaft 55. In addition, since the rotating case 66 and the second propeller shaft 71 rotate at the same rotation speed, a differential rotation also occurs between the first propeller shaft 55 and the second propeller shaft 71, and the rotation speed of the second propeller shaft 71 becomes higher (accelerated) than the rotation speed of the first propeller shaft 55. Thus, in the vehicle 2 , the rear wheels 60 rotate faster than the front wheels 53 .

[0086] Furthermore, the rotating shaft 72 is connected to the rotating case 66 via a lock mechanism 68. Therefore, no differential rotation occurs between the second propeller shaft 71 and the rotating shaft 72. As a result, the ball screw 73 provided between the second propeller shaft 71 and the rotary shaft 72 does not move in either direction and maintains its current position. Therefore, the length of the elastic member 74 is also maintained.

[0087] In this manner, in the power retention mode, the contraction energy stored in the elastic member 74 is retained.

[0088] 12 is a diagram showing the power transmission path in the power release mode. In the vehicle 2, when contraction energy is stored in the elastic member 74 during towing, the vehicle 2 transitions to the power release mode when the power release condition is satisfied.

[0089] The power release condition occurs when the vehicle 2 is stopped or coasting, contraction energy is stored in the elastic member 74, and the battery 80 is capable of being charged.

[0090] 7 and 12, in the power release mode, similarly to the towing travel mode, hydraulic pressure is generated by the pressure generating unit 30, the on-off valve 40 is turned on, and hydraulic pressure is supplied to the through clutch 64 and the speed-up clutch 65. In addition, the ECU 81 closes the valve 45. Then, the through clutch 64 is released, and the speed-up clutch 65 is also released. Further, the ECU 81 performs control so as to disengage the disconnect clutch 54, engage the transfer clutch 56, engage the engaging clutch 67, and disengage the lock mechanism 68. Furthermore, the ECU 81 controls the motor generator 51 to perform regenerative operation.

[0091] As a result, as shown in FIG. 12, the motor generator 51 is not connected to the rear wheels 60 by any path. Furthermore, power is not transmitted to the front wheels 53 because the disconnect clutch 54 is open. The motor generator 51 is connected to a rotary shaft 72 via the front differential gear 52 , the first propeller shaft 55 and the coupling clutch 67 .

[0092] This allows the rotating shaft 72 to rotate freely. Then, the elastic member 74, which retains the contraction energy, tries to return to its original shape, causing the ball screw 73 to move toward the engaging clutch 67, and the rotating shaft 72 rotates accordingly.

[0093] When the rotating shaft 72 rotates, the rotating shaft of the motor generator 51 is rotated through the engagement clutch 67, the first propeller shaft 55, and the front differential gear 52, and the motor generator 51 generates electricity.

[0094] In this manner, in the power release mode, it is possible to charge the battery 80 by the contraction energy stored in the elastic member 74.

[0095] During towing, the vehicle 2 switches between a towing driving mode, a power storage mode, a power retention mode, and a power release mode as appropriate according to the driving state. As a result, in the vehicle 2, energy (power) that is not used for power generation in the battery 80 is stored in the elastic member 74 as appropriate, and when the battery 80 is chargeable, the stored energy is released to charge the battery 80. This makes it possible to reduce the power loss during towing in the vehicle 2, and also to reduce the energy loss.

[0096] Fig. 13 is a flowchart showing the flow of control by the ECU 81. As shown in Fig. 13, in step S1, the ECU 81 determines whether a tongue weight of a predetermined value or more is applied to the vehicle-side coupling part 10. Here, it determines whether the on-off valve 40 is turned on. As a method of determining the tongue weight, it may be determined that the on-off valve 40 is turned on, or the tongue weight applied to the vehicle-side coupling part 10 may be directly measured.

[0097] If a tongue weight equal to or greater than the predetermined value has not been applied (No in step S1), the ECU 81 transitions to a normal driving mode in step S2, and proceeds to step S10.

[0098] If a tongue weight equal to or greater than the predetermined value has been applied (Yes in step S1), the ECU 81 determines in step S3 whether a power storage condition is met. If the power accumulation condition is met (Yes in step S3), the ECU 81 transitions to the power accumulation mode in step S4, and proceeds to step S10.

[0099] If the power accumulation condition is not satisfied (No in step S3), the ECU 81 determines in step S5 whether the power retention condition is satisfied. If the power retaining condition is met (Yes in step S5), the ECU 81 transitions to the power retaining mode in step S6, and proceeds to step S10.

[0100] When the power holding condition is not satisfied (No in step S5), the ECU 81 determines in step S7 whether the power release condition is satisfied. If the power release condition is met (Yes in step S7), the ECU 81 transitions to the power release mode in step S8, and proceeds to step S10.

[0101] If the power release condition is not satisfied (No in step S7), the ECU 81 transitions to the towing travel mode in step S9, and proceeds to step S10.

[0102] In step S10, the ECU 81 controls the valves, clutches, etc. in accordance with the transition mode as described above, and then ends the process.

[0103] <3. Modifications> Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned specific examples and can adopt various configurations. For example, in the above embodiment, the differential rotation generating mechanism 57 uses the speed-increasing clutch 65 to increase the rotation speed of the rear wheels 60, thereby making the rotation speed of the rear wheels 60 higher than the rotation speed of the front wheels 53. However, the differential rotation generating mechanism 57 may also be configured to make the rotation speed of the rear wheels 60 higher than the rotation speed of the front wheels 53 by lowering the rotation speed of the front wheels 53.

[0104] <4. Summary of the embodiment> As described above, the vehicle 2 of the embodiment is equipped with a coupling portion (vehicle side coupling portion 10) for coupling the trailer 3, and a differential rotation generating mechanism 57 that generates differential rotation between the front wheels 53 and the rear wheels 60 when a tongue weight of a predetermined value or more is added to the coupling portion. Even when the moving radius of the rear wheels 60 becomes small due to tongue weight generated when the trailer 3 is coupled, the vehicle 2 makes the rotation speed of the rear wheels 60 higher than the rotation speed of the front wheels 53. This makes it possible for the vehicle 2 to offset these and reduce the difference in the moving distance between the front wheels 53 and the rear wheels 60. As a result, in the vehicle 2, the driving loss caused by the smaller moving radius of the rear wheels 60 can be reduced.

[0105] The coupling portion (vehicle side coupling portion 10) comprises a lever 13 rotatably supported on a support portion 12 fixed to the vehicle body 5, a connection portion (hitch ball 15) provided on one end of the lever 13 to which the trailer 3 is connected, and a pressure generating portion 30 provided on the other end of the lever 13 for generating pressure in response to the rotation of the lever 13 due to the trailer 3 being coupled to the connection portion. As a result, the hitch coupler 22 of the trailer 3 engages with the hitch ball 15, and part of the weight of the trailer 3 is added to it. At this time, the lever 13 rotates about the support part 12 as a fulcrum, generating pressure in the pressure generating part 30. The pressure generating part 30 can increase the rotation speed of the rear wheels 60 by the generated pressure. In this way, in the vehicle 2, the driving loss can be reduced with a simple configuration without performing electrical control or the like.

[0106] The differential rotation generating mechanism 57 includes a group of gears (ring gear 61, pinion gear 62, ring gear 63) that accelerates the speed of the rear wheel 60 on the power transmission path from the power source (motor generator 51) to the rear wheel 60, a first clutch (speed-through clutch 64) that can connect the power source to the rear wheel 60 on the power transmission path without going through the gear group, and a second clutch (speed-accelerating clutch 65) that can connect the power source to the rear wheel 60 on the power transmission path via the gear group, and when no pressure is received from the pressure generating unit 30, the first clutch is engaged and the second clutch is disengaged, and when pressure is received from the pressure generating unit 30, the first clutch is disengaged and the second clutch is engaged. This makes it possible to increase the rotation speed of the rear wheels 60 by the speed increasing clutch 65 in response to the addition of part of the weight of the trailer 3 to the vehicle side coupling 10. Also, when part of the weight of the trailer 3 is not added to the vehicle side coupling 10, the rotation speed of the rear wheels 60 can be made the same as the rotation speed of the front wheels 53. In this way, in the vehicle 2, the rotation speed of the rear wheels 60 can be increased during towing due to the mechanical configuration.

[0107] An energy storage mechanism 58 is provided that can store energy from the differential rotation generated by the differential rotation generating mechanism 57. As a result, even when, for example, battery 80 cannot be charged or the amount of power generated by motor generator 51 increases by the weight of trailer 3 and the power generated by motor generator 51 cannot be charged to battery 80, the energy can be stored in energy storage mechanism 58. Therefore, energy loss in vehicle 2 can be reduced.

[0108] The energy storage mechanism 58 comprises a rotating shaft 72 connected to a power source, a shaft (second propeller shaft 71) whose speed is increased relative to the rotating shaft by the differential rotation generating mechanism 57, a ball screw 73 sandwiched between the rotating shaft 72 and the shaft, and an elastic member 74 that can expand and contract as the ball screw 73 moves. As a result, in the energy storage mechanism 58, by using a configuration in which the rotation speed of the second propeller shaft 71 is increased in order to reduce drive loss, it becomes possible to store contraction energy in the elastic member 74. That is, in the vehicle 2, it is possible to achieve both reduction in drive loss and reduction in energy loss. [Explanation of symbols]

[0109] 1 Vehicle Systems 2 Vehicles 3. Trailer 6 Rear wheel 10 Vehicle side coupling 57 Differential rotation generating mechanism 58 Energy storage mechanism

Claims

1. A coupling portion for coupling a trailer; a differential rotation generating mechanism that generates a differential rotation between the front wheels and the rear wheels when a tongue weight of a predetermined value or more is applied to the connecting portion; A vehicle equipped with.

2. The connecting portion is A lever rotatably supported on a support part fixed to a vehicle body; a connection portion provided on one end side of the lever and to which the trailer is connected; a pressure generating section provided on the other end side of the lever and configured to generate pressure in response to rotation of the lever caused by connecting the trailer to the connecting section; 2. The vehicle of claim 1.

3. The differential rotation generating mechanism is a group of gears arranged on a power transmission path from a power source to the rear wheels to increase the rotation speed of the rear wheels; a first clutch that can connect the power source and the rear wheel on the power transmission path without passing through the gear group; a second clutch that is capable of connecting the power source and the rear wheel via the gear group on the power transmission path, When no pressure is received from the pressure generating portion, the first clutch is engaged and the second clutch is disengaged, When pressure is received from the pressure generating portion, the first clutch is released and the second clutch is engaged.

3. A vehicle as claimed in claim 2.

4. The differential rotation generating mechanism is provided with an energy storage mechanism capable of storing energy generated by the differential rotation generating mechanism. A vehicle according to claim 1 or 2.

5. The energy storage mechanism includes: A rotating shaft connected to a power source; a shaft whose speed is increased relative to the rotating shaft by the differential rotation generating mechanism; a ball screw sandwiched between the rotating shaft and the shaft; an elastic member that can expand and contract in accordance with the movement of the ball screw; The vehicle of claim 4 .

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