JP2009292307A - Driving force transmission device for four-wheel drive car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device for a four-wheel drive car capable of preventing low fuel-efficiency at the time of two-wheel driving by completely stopping rotation of a driving-force transmitting path to rear wheels at the time of the two-wheel driving. <P>SOLUTION: The power transmission device is provided with a front-wheel differential 16 for receiving input driving-force and outputting the driving-force to right-and-left front wheels 46, 48 and to a driving-force distribution device 14 via a bevel gear 50 and an output pinion 52, a rear-wheel differential 18 for receiving input driving-force distributed from the driving-force distribution device 14 and outputting the driving-force to right-and-left rear wheels 80, 82, a first clutch mechanism 20 capable of interrupting and permitting driving-force transmission between the front-wheel differential 16 and the bevel gear 50, and a second clutch mechanism 22 capable of interrupting and permitting driving-force transmission between the rear-wheel differential 18 and a right rear-wheel driving axle 78. In a four-wheel drive mode, the first clutch mechanism 20 and the second clutch mechanism 22 are connected with each other and driving-force distribution of the driving-force distribution device 14 is automatically controlled according to a traveling condition. In a two-wheel drive mode, the first clutch mechanism 20 and the second clutch mechanism 22 are disengaged. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a drive power transmission device for a four-wheel drive vehicle capable of switching between two-wheel drive and four-wheel drive, and in particular, a drive force for a four-wheel drive vehicle that stops rotation of a portion not related to transmission of the drive force during two-wheel drive. Related to the transmission device.

  In a conventional so-called on-demand full-time four-wheel drive vehicle, the driving force for a four-wheel drive vehicle is controlled by a multi-plate clutch mechanism that drives the front wheels during two-wheel drive and controls the distribution of the drive force to the rear wheels during four-wheel drive. As a transmission device, for example, the one shown in FIG. 6 is known.

  In FIG. 6, the driving force transmission device 400 is provided in the four-wheel drive vehicle 402, and the driving force from the engine 404 is shifted by the transmission 406, and the front wheel differential is transmitted via the output gear 408 and the ring gear 410 of the transmission 406. The signal is input to the device 412 and also transmitted to the output pinion 416 via the bevel gear 414 connected to the front wheel differential device 412.

  When the driving force from the output pinion 416 is transmitted to the multi-plate clutch mechanism 420 (driving force distribution device) via the propeller shaft 418, when the multi-plate clutch mechanism 420 is released (disengaged) during two-wheel drive. The driving force is not transmitted to the rear wheel differential device 426 but is transmitted only to the front wheel differential device 412. The front wheel differential device 412 absorbs the rotational speed difference between the left front wheel 428 and the right front wheel 430, and the left front wheel 428. The right front wheel 430 is rotated by giving an equal torque.

  When the multi-plate clutch mechanism 420 is fastened (connected) during four-wheel drive, the driving force is transmitted to the rear-wheel differential device 426 via the drive pinion 422 and the ring gear 424 connected to the multi-plate clutch mechanism 420. The rear wheel differential device 426 absorbs the difference in rotational speed between the left rear wheel 432 and the right rear wheel 434 and rotates the left rear wheel 432 and the right rear wheel 434 with the same torque.

  In general, on-demand full-time four-wheel drive vehicles are available in two-wheel drive mode, four-wheel drive auto mode, and four-wheel drive lock mode as drive modes that can be selected by the driver during operation. .

  The two-wheel drive mode is a mode in which the multi-plate clutch mechanism 420 of the drive force transmission device 400 is opened and used in a two-wheel drive state, and travels on a dry pavement or the like that does not require a four-wheel drive force because it has the best fuel efficiency. Select if you want to.

  In the four-wheel drive auto mode, various vehicle conditions during traveling are detected by sensors, and the distribution of driving force to the front and rear wheels of the multi-plate clutch mechanism 420 is optimized by an ECU (Electronic Control Unit) based on the detection signal. This mode is automatically controlled, and is a four-wheel drive that can always be selected regardless of the road surface condition.

  In this mode, the fastening force of the multi-plate clutch mechanism 420 is continuously increased or decreased by an electromagnetic actuator or a hydraulic actuator, and the front and rear wheels are driven between the two-wheel drive state in which the driving force to the rear wheels is substantially zero and the maximum fastening force. Control power distribution.

  The four-wheel drive lock mode is a mode that keeps the multi-plate clutch mechanism 420 at the maximum engagement force regardless of the vehicle state detected by various sensors, and maximizes the driving performance as a four-wheel drive on rough roads. Select if you want to.

In addition, in this application, when it is not necessary to distinguish clearly, a four-wheel drive auto mode and a four-wheel drive lock mode are named generically as a four-wheel drive mode.
Japanese Patent Laid-Open No. 11-125279

  However, in the conventional driving force transmission device for a four-wheel drive vehicle as shown in FIG. 6, the driving force from the transmission 406 is the bevel gear 414, the output pinion 416, and the propeller shaft 418 even in the two-wheel drive mode. In addition, the drive side (front wheel side) of the multi-plate clutch mechanism 420 is rotated, and the left rear wheel 432 and the right rear wheel 434 and the rear wheel differential 426 are directly connected, so the left rear wheel 432 and the right rear wheel By rotating 434, the rear wheel differential 426, the ring gear 424, the drive pinion 422, and the driven side (rear wheel side) of the multi-plate clutch mechanism 420 rotate.

  That is, even when the multi-plate clutch mechanism 420 is completely opened when the multi-plate clutch mechanism 420 is opened and the driving force is not transmitted to the rear wheels, even if the multi-plate clutch mechanism 420 is completely released, the bevel gear 414, the output pinion 416, Each component of the rear wheel driving force transmission section 436 including the propeller shaft 418, the multi-plate clutch mechanism 420, the drive pinion 422, the ring gear 424, and the rear wheel differential 426 rotates, and the oil stirring resistance in this section In addition, there is a problem in that fuel efficiency is reduced due to power loss due to friction loss of the bearing portion.

  The multi-plate clutch mechanism 420 is provided with a plurality of clutch plates and is lubricated and cooled by oil. However, the oil viscous resistance generated by the difference in rotational speed between the drive side and the driven side of the clutch plate and The so-called drag torque generated by the friction loss due to contact is larger than the meshing force of the drive pinion 422 and the ring gear 424 and the friction torque of the rear wheel differential 426, so that even if the left rear wheel 432 and the right rear wheel 434 rotate. Even if the transmission is not transmitted to the rear wheel differential 426, the drive pinion 422, the ring gear 424, and the rear wheel differential 324 are rotated from the multi-plate clutch mechanism 420 side, resulting in power loss and deterioration in fuel consumption. There is also a problem to make.

  Thus, in the conventional on-demand type full-time four-wheel drive vehicle, by reducing the transmission torque of the driving force distribution device (multi-plate clutch mechanism 420) to zero, the driving force is two-wheel drive vehicle. However, the transmission path (rear wheel driving force transmission section 436) until the driving force from the engine is transmitted to the rear wheels is always rotating. Therefore, even in the two-wheel drive mode, the four-wheel drive vehicle has a problem that the fuel consumption is worse than that of the two-wheel drive vehicle.

An object of the present invention is to provide a power transmission device for a four-wheel drive vehicle that does not cause a reduction in fuel consumption during two-wheel drive by completely stopping rotation of a drive force transmission path to a rear wheel during two-wheel drive.

  In order to achieve this object, the present invention is configured as follows. First, the present invention is provided with a driving force distribution device capable of steplessly changing the driving force transmitted to the rear wheels, a four-wheel drive mode for distributing the driving force to the front wheels and the rear wheels, and transmitting the driving force only to the front wheels. The target is a four-wheel drive vehicle driving force transmission device capable of switching between two-wheel drive modes.

  The present invention provides a driving force transmission device for such a four-wheel drive vehicle in which a driving force from a power source is input and output to the driving force distribution device via the left and right front wheels and the driving force transmission direction converter. Disconnects the driving force transmission between the differential, the rear wheel differential that inputs the driving force distributed by the driving force distribution device and outputs it to the left and right rear wheels, and the front wheel differential and the driving force transmission direction changer. And a connectable first connecting / disconnecting mechanism, and a second connecting / disconnecting mechanism capable of disconnecting and connecting the driving force transmission to either one or both of the rear wheel differential and the left and right rear wheels.

  Alternatively, in such a driving force transmission device for a four-wheel drive vehicle, the driving force from the power source is input and output to the left and right front wheels and the driving force distribution device, and distributed by the driving force distribution device. The driving force transmission between the rear wheel differential device that inputs the generated driving force via the driving force transmission direction conversion unit and outputs it to the left and right rear wheels, and the driving force transmission between the front wheel differential device and the driving force distribution device can be disconnected and connected. A first connection / disconnection mechanism, and a second connection / disconnection mechanism capable of disconnecting and connecting the driving force transmission between one or both of the rear wheel differential device and the left and right rear wheels, are provided.

  Here, the four-wheel drive mode connects the first connecting / disconnecting mechanism and the second connecting / disconnecting mechanism, and controls the driving force distribution of the driving force distribution device according to the traveling condition. The contact mechanism and the second connection / disconnection mechanism are cut.

  The rear wheel differential device includes a first output element and a second output element that output driving force to the rear wheel, and the second connecting / disconnecting mechanism disconnects driving force transmission between the rear wheel and the first output element. And connectable.

  Alternatively, the rear wheel differential device includes a first output element and a second output element that output driving force to the rear wheel, and the second connecting / disconnecting mechanism includes a rear wheel and the first output element and the second output element. The driving force transmission can be disconnected and connected.

  Alternatively, the rear wheel differential device includes an input element that inputs the driving force from the driving force distribution device and an output element that outputs the driving force to the rear wheel, and the second connecting / disconnecting mechanism includes the input element and the output element. It is possible to disconnect and connect the driving force transmission.

Further, the driving force distribution device controls the distribution of the driving force transmitted to the front wheels and the rear wheels by continuously changing the fastening force of the multi-plate clutch mechanism.

According to the present invention, the first connecting / disconnecting mechanism capable of connecting / disconnecting the driving force transmission between the front wheel differential device and the driving force distribution device, and driving the rear wheel differential device and / or the left and right rear wheels. A second connection / disconnection mechanism capable of connecting / disconnecting force transmission is provided, and in the two-wheel drive mode, the first connection / disconnection mechanism and the second connection / disconnection mechanism are disconnected to completely stop the rotation of the driving force transmission path to the rear wheels. As a result, fuel consumption can be prevented from being reduced during two-wheel drive, and fuel efficiency equivalent to that of a two-wheel drive vehicle can be achieved despite being a four-wheel drive vehicle.

  FIG. 1 is an explanatory view showing a first embodiment of a driving force transmission device for a four-wheel drive vehicle according to the present invention, and is in a state of a four-wheel drive mode. In FIG. 1, the driving force transmission device 10 of this embodiment is provided in a four-wheel drive vehicle 12, and includes a driving force distribution device 14, a front wheel differential device 16, a rear wheel differential device 18, a first connecting / disconnecting mechanism 20, and A two-connection mechanism 22 is provided.

  The driving force from the engine 24 is shifted by the transmission 26 and is input to the front wheel differential device 16 from the output gear 28 of the transmission 26 via the ring gear 30, and the front wheel differential device 16 rotates inside the differential case 32. The left front wheel drive shaft 42 and the right front wheel drive shaft 44 are driven via the freely supported pinions 34, 36 and the side gears 38, 40 engaged with the pinions 34, 36, and the left front wheel drive shaft 42 and the right front wheel drive are driven. The shafts 44 respectively rotate the left front wheel 46 and the right front wheel 48 to transmit driving force to the road surface.

  Even if a rotational speed difference occurs between the left front wheel 46 and the right front wheel 54 due to cornering or changes in road surface conditions, the front wheel differential 16 absorbs the rotational speed difference and gives equal torque to the left front wheel 46 and the right front wheel 48. Can be rotated.

  The driving force input to the front wheel differential device 16 is also transmitted to the first connecting / disconnecting mechanism 20 connected to the differential case 32. When the first connecting / disconnecting mechanism 20 is connected in the four-wheel drive mode, the bevel gear 50 and The transmission direction of the driving force is converted by the output pinion 52 (driving force transmission direction converting portion), and is also transmitted to the driving force distribution device 14 via the universal joint 54, the propeller shaft 56, and the universal joint 58.

  In the four-wheel drive mode, since the multi-plate clutch mechanism 60 of the driving force distribution device 14 is fastened, the driving force input to the driving force distribution device 14 is the difference between the rear wheels via the drive pinion 62 and the ring gear 64. The rear wheel differential device 18 is transmitted to the moving device 18, and the rear wheel differential device 18 is connected to the left rear wheel via pinions 68, 70 rotatably supported inside the differential case 66 and side gears 72, 74 engaged with the pinions 68, 70. The drive shaft 76 and the right rear wheel drive shaft 78 are driven, and the left rear wheel drive shaft 76 and the right rear wheel drive shaft 78 rotate the left rear wheel 80 and the right rear wheel 82, respectively, and transmit the driving force to the road surface.

  In the four-wheel drive mode, the second connecting / disconnecting mechanism 22 is connected to connect the side gear 74 and the right rear wheel drive shaft 78, and the rotation of the side gear 74 is transmitted to the right rear wheel drive shaft 78 as it is.

  Even if a difference in rotational speed occurs between the left rear wheel 80 and the right rear wheel 82 due to cornering or changes in road surface conditions, the rear wheel differential 18 absorbs the rotational speed difference, and the left rear wheel 80 and the right rear wheel 82 Can be rotated by applying a torque equal to.

  In the four-wheel drive auto mode, the ECU 84 continuously changes the fastening force of the multi-plate clutch mechanism 60 and increases or decreases the driving force transmitted to the drive pinion 62 as necessary. The wheel driving force distribution is controlled, and in the four-wheel drive lock mode, the multi-plate clutch mechanism 60 is held at the maximum fastening force, and the rear wheels are driven with a predetermined maximum torque.

  When the four-wheel drive mode is switched to the two-wheel drive mode, the ECU 84 first opens the multi-plate clutch mechanism 60, and then disconnects the first connection / disconnection mechanism 20 and the second connection / disconnection mechanism 22. In this case, the ECU 84 may release the multi-plate clutch mechanism 60 after first disconnecting the connection between the first connecting / disconnecting mechanism 20 and the second connecting / disconnecting mechanism 22.

  The first connecting / disconnecting mechanism 20 disconnects the differential case 32 of the front wheel differential device 16 from the bevel gear 50, and the driving force input to the ring gear 30 causes the output pinion 52, the universal joint 54, the propeller shaft 56, and the universal joint 58 to be connected. This prevents the multi-plate clutch mechanism 60 from rotating.

  Further, the second connecting / disconnecting mechanism 22 disconnects the connection between the side gear 74 of the rear wheel differential 18 and the right rear wheel drive shaft 78, and the rotational force received by the left rear wheel 80 and the right rear wheel 82 from the road surface is a ring gear. 64, the drive pinion 62 and the multi-plate clutch mechanism 60 are prevented from rotating.

  Thereby, in the two-wheel drive mode, the rotation from the front and rear wheels is not transmitted to the multi-plate clutch mechanism 60, and the section from the bevel gear 50 through the multi-plate clutch mechanism 60 to the differential case 66 does not rotate. Therefore, it is possible to solve the problem that the driving force transmission path to the rear wheels rotates even when the rear wheels are not driven, which is a factor that causes a reduction in fuel consumption in the two-wheel drive mode.

  In FIG. 1, if the side gear 74 of the rear wheel differential 18 and the right rear wheel drive shaft 78 are connected in the two-wheel drive mode, for example, when the side gears 72 and 74 rotate in the same direction and at the same speed, The differential case 66 and the ring gear 64 rotate without rotating (rotating) the pinion 68 and the pinion 70.

  Even if there is a difference in rotational speed between the side gears 72 and 74, if the rotational speed is the same, the rotational speed will change, but the differential case 66 will rotate, and the differential gear 66 and the ring gear 64 will rotate to engage the drive pinion. 62 and the multi-plate clutch mechanism 60 are rotated.

  If the multi-plate clutch mechanism 60 generates drag torque, the rotation of the multi-plate clutch mechanism 60 is further transmitted to the bevel gear 50 via the universal joint 58, the propeller shaft 56, the universal joint 54, and the output pinion 52. .

  Although the section from the differential case 66 to the bevel gear 50 is a portion that does not need to be rotated during two-wheel drive, the rotation of this portion causes oil viscosity resistance, friction loss of the bearing portion, and the like. That is, the driving force transmitted to the road surface from the left front wheel 46 and the right front wheel 48 rotates the left rear wheel 80 and the right rear wheel 82, thereby rotating this section that does not need to be rotated during two-wheel drive, resulting in power loss and fuel consumption. It will cause a decline.

  Therefore, in the present invention, in the two-wheel drive mode, the first connecting / disconnecting mechanism 20 disconnects the driving force input to the front wheel differential device 16 to the multi-plate clutch mechanism 60 and the second connecting / disconnecting mechanism. 22, the side gear 74 and the right rear wheel drive shaft 78 are disconnected from each other, thereby preventing the drive force transmission path from the bevel gear 50 to the differential case 66 from rotating.

  When the connection between the side gear 74 and the right rear wheel drive shaft 78 is broken, the rotation of the right rear wheel 82 is not transmitted to the side gear 74, and therefore the rotation of the side gear 72 by the left rear wheel 80 is performed via the pinions 68 and 70. Since the rotational resistance from the drive pinion 62 connected to the ring gear 64 to the bevel gear 50 is greater than the rotational resistance of the pinions 68 and 70 and the side gear 74, the differential case 66 does not rotate. .

  The fact that the ring gear 64 does not rotate means that the driving force transmission path to the rear wheels does not rotate. In this case, the power loss is only the portion where the pinions 68 and 70 and the side gear 74 rotate, and the first connecting / disconnecting mechanism. The fuel consumption can be improved compared to the case where the driving force transmission path to the rear wheel rotates without the 20 and the second connecting / disconnecting mechanism 22.

  FIG. 2 is a cross-sectional view showing the front wheel differential device 16 and the first connecting / disconnecting mechanism 20 of FIG. 1, and the upper side of the drawing is the front side (forward direction) of the four-wheel drive vehicle 12. In FIG. 2, the front wheel differential device 16, the first connection / disconnection mechanism 20, the bevel gear 50, and the output pinion 52 are accommodated in a housing 86 connected to the transmission 26.

  The front wheel differential device 16 located on the left side of the housing 86 includes a ring gear 30 fixed to the flange portion 32a of the differential case 32, pinions 34 and 36 rotatably supported on a pinion shaft 88 fixed to the differential case 32, A side gear 38 that is rotatably supported by the differential case 32 and rotatably connected to the left front wheel drive shaft 42 and a side gear 40 that is rotatably supported by the differential case 32 and rotatably connected to the right front wheel drive shaft 44 are provided.

  The ring gear 30 meshes with the output gear 28 of the transmission 26, and the side gears 38 and 40 mesh with the pinions 34 and 36, respectively. The differential case 32 is rotatably supported on the housing 86 by tapered roller bearings 90 and 92 on both the left front wheel drive shaft 42 side and the right front wheel drive shaft 44 side, respectively.

  The right side of the housing 86 is provided with a bevel gear shaft 94 that is non-rotatably fitted to the bevel gear 50 coaxially with the differential case 32. The bevel gear shaft 94 is housed on both sides of the differential case 32 side and the bevel gear 50 side by tapered roller bearings 96 and 98, respectively. 86 is rotatably supported.

  An output pinion 52 that meshes with the bevel gear 50 is provided on the lower right side of the housing 86, and the output pinion 52 is coupled to the propeller shaft 56 via a universal joint 54 that is connected downward. A first connecting / disconnecting mechanism 20 is provided between the front wheel differential 16 and the bevel gear 50.

  The first connecting / disconnecting mechanism 20 is spline-coupled with the tooth portion 32b formed on the outer periphery of the right end of the differential case 32 and the tooth portion 94a formed on the outer periphery of the left end of the bevel gear shaft 94, and the tooth portions 32b and 94a to connect the differential case 32 and the bevel gear shaft 94. The sleeve 100 is slidable at the position where it is to be disconnected and the position at which the connection is released, the fork 102 is slidable by the tip portion 102a slidably engaged with the groove portion 100a of the sleeve 100, and the shaft is driven by an actuator (not shown) fixed to the fork 102. It consists of a shift shaft 104 driven in the direction.

  FIG. 2 shows a state in which the first connecting / disconnecting mechanism 20 is not connected at the time of two-wheel drive, and the sleeve 100 is not engaged with the tooth portion 32b of the differential case 32, and the connection between the differential case 32 and the bevel gear shaft 94 is released. In position.

  During four-wheel drive, the sleeve 100 connects the differential case 32 and the bevel gear shaft 94 by sliding the shift shaft 104 in the C direction (illustrated by an imaginary line), and the first connecting / disconnecting mechanism 20 is connected. In this state, the driving force from the output gear 28 meshing with the ring gear 30 can be transmitted to the propeller shaft 56 via the bevel gear 50 and the output pinion 52.

  When returning to the two-wheel drive, the sleeve 100 releases the connection between the differential case 32 and the bevel gear shaft 94 by sliding the shift shaft 104 in the D direction, and the first connecting / disconnecting mechanism 20 is disconnected. In this state, the driving force from the output gear 28 is not transmitted to the propeller shaft 56.

  FIG. 3 is a cross-sectional view showing the driving force distribution device 14, the rear wheel differential device 18, and the second connecting / disconnecting mechanism 22 of FIG. 1, and the upper side of the drawing is the front side (forward direction) of the four-wheel drive vehicle 12. . In FIG. 3, the second connecting / disconnecting mechanism 22 is accommodated in the housing 106 to the right of the driving force distribution device 14, the drive pinion 62, the rear wheel differential device 18, and the rear wheel differential device 18 from the upper side to the lower side.

  In the present embodiment, the driving force distribution device 14 is configured by a multi-plate clutch mechanism 60 that is hydraulically controlled, and continuously changes the fastening force of the multi-plate clutch mechanism 60 during four-wheel drive and transmits it to the rear wheels 80 and 82. Control the distribution of driving force.

  The multi-plate clutch mechanism 60 includes a clutch drum 108 that connects a universal joint 58 to an upper end portion 108a and inputs a driving force from a propeller shaft 56, a clutch hub 110 that non-rotatably engages a drive pinion 62 coaxially with the clutch drum 108, A ball cam mechanism 114 that presses a multi-plate clutch 112 provided between the clutch drum 108 and the clutch hub 110 and a primary clutch 116 that drives the ball cam mechanism 114 are provided.

  The drive pinion 62 has a shaft portion 62a rotatably supported on the housing 106 by tapered roller bearings 118 and 120, and the clutch drum 108 has an upper end portion 108a rotatably supported on the housing 106 by a ball bearing 122. The other end of the drive pinion 62 is rotatably supported by a ball bearing 124 with respect to the shaft portion 62a of the drive pinion 62. In addition, the clutch hub 110 is inserted and fitted with the pinion 62 from below and is held, and the upper end of the clutch hub 110 is rotatably held by the ball bearing 126 with respect to the clutch drum 108.

  The ball cam mechanism 114 holds the ball 132 with a ball 132 sandwiched between a pair of pressing cam plates 128 provided coaxially with the clutch hub 110 and a cam surface facing the rotating cam plate 130.

  The multi-plate clutch 112 is held so as to be movable in the axial direction with respect to the clutch hub 110 or the clutch drum 108 between a pressing portion 128 a of the pressing cam plate 128 and a pressure receiving portion 108 b of the clutch drum 108.

  The pressing cam plate 128 is splined to the clutch hub 110 and is movable in the axial direction. The pressing cam plate 128 rotates together with the clutch hub 110, and is attached to the release direction of the multi-plate clutch mechanism 60 by a disc spring 134 provided between the pressing cam plate 128 and the clutch hub 110. It is energized.

  The rotating cam plate 130 is rotatably held by the clutch hub 110 and rotates together with the pressing cam plate 128 via a ball 132. A thrust bearing 136 is provided between the rotating cam plate 130 and the clutch drum 108, and the clutch drum The difference in rotational speed with respect to 108 is absorbed.

  The primary clutch 116 includes a clutch plate 138 that is held between the clutch drum 108 and the rotating cam plate 130 so as to be movable in the axial direction with respect to the rotating cam plate 130, and rotates together with the rotating cam plate 130. The clutch plate 138 is pressed against the pressure receiving plate 142 fixed to the drum 108 and fastened to transmit the rotational speed difference between the clutch drum 108 and the clutch hub 110 to the rotating cam plate 130.

  A hydraulic piston mechanism 144 that controls the fastening force of the multi-plate clutch 112 via a primary clutch 116 and a ball cam mechanism 114, and a hydraulic pump that supplies hydraulic pressure to the hydraulic piston mechanism 144, in the middle portion of the housing 106 below the clutch drum 108. 146, a servo motor 148 for driving the hydraulic pump 146 and a hydraulic sensor 150 for detecting the hydraulic pressure thereof.

  The pressing plate 140 of the primary clutch 116 is connected to a thrust bearing 154 via a pressing shaft 152 that slidably penetrates the clutch drum 108, and the thrust bearing 154 engages with a ring-shaped hydraulic piston 156 of the hydraulic piston mechanism 144. ing. The hydraulic piston 156 is loosely fitted inside a hydraulic cylinder 158 formed in the housing 106, and is movable to a position where the primary clutch 116 is disengaged and a position where it is fastened.

  When the rotary cam plate 130 is driven to rotate relative to the pressing cam plate 128 in a predetermined direction by the primary clutch 116, the ball cam mechanism 114 is pressed by the ball 132 sandwiched between the ball cam grooves that are inclined grooves on the opposing surfaces. Then, the pressing cam plate 128 and the disc spring 134 are pressed in the axial direction, and the pressing portion 128 a of the pressing cam plate 128 presses the multi-plate clutch 112 of the multi-plate clutch mechanism 60. The transmission torque is increased according to the amount of movement, and a direct connection state is established at the maximum pressing position.

  In this embodiment, a hydraulic actuator by the hydraulic piston mechanism 144 is used to control the fastening force of the multi-plate clutch mechanism 60. However, this is not limited to a hydraulic actuator, and may be an electromagnetic actuator or other actuator, for example. I do not care. Which actuator is used can be appropriately selected.

  A rear wheel differential 18 is provided on the lower side of the housing 106, and a ring gear 64 fixed to the flange portion 66 a of the differential case 66 and a pinion 68 rotatably supported by a pinion shaft 160 fixed to the differential case 66. And 70, a side gear 72 rotatably supported on the differential case 66 and non-rotatably connected to the left rear wheel drive shaft 76, and a side gear 74 rotatably supported on the differential case 66 and non-rotatably connected to the side gear shaft 162.

  The ring gear 64 meshes with the drive pinion 62 connected to the multi-plate clutch mechanism 60, and the side gears 72 and 74 mesh with the pinions 68 and 70, respectively. The differential case 66 is rotatably supported on the housing 106 by tapered roller bearings 164 and 166 on both sides of the left rear wheel drive shaft 76 side and the side gear shaft 162 side.

  A second connecting / disconnecting mechanism 22 is provided on the lower right side of the housing 106, and the second connecting / disconnecting mechanism 22 is formed on the outer periphery of the left end of the right rear wheel drive shaft 78 and the tooth portion 162 a formed on the right end surface portion of the side gear shaft 162. A toothed portion 78a, a sleeve 168 slidable at a position where the side gear shaft 162 and the right rear wheel drive shaft 78 are connected to and disconnected from each other by engaging the toothed portion 162a and the toothed portion 168a by spline coupling with the toothed portion 78a. The front end 170a slidably engages with the groove 168b of the sleeve 168. The fork 170 slides the sleeve 168, and the shift shaft 172 is fixed to the fork 170 and driven in the axial direction by an actuator (not shown).

  FIG. 3 shows a state in which the second connecting / disconnecting mechanism 22 is connected during four-wheel drive, and the sleeve 168 is engaged with the tooth portion 168a and the tooth portion 162a of the side gear shaft 162, and the side gear shaft 162 and the right side. It exists in the position which connects with the rear-wheel drive shaft 78. In this state, the driving force from the drive pinion 62 meshing with the ring gear 64 can be transmitted to the right rear wheel 82 via the right rear wheel drive shaft 78.

  At the time of two-wheel drive, the shift shaft 172 is slid in the D direction to release the connection of the sleeve 168 with the side gear shaft 162 (illustrated by an imaginary line), and the second connecting / disconnecting mechanism 22 is disconnected, and the four-wheel drive is performed. When returning to, the shift shaft 172 is slid in the C direction so that the sleeve 168 connects the side gear shaft 162 and the right rear wheel drive shaft 78, and the second connecting / disconnecting mechanism 22 is in a connected state.

  In the present embodiment, the first connecting / disconnecting mechanism 20 shown in FIG. 2 uses a sliding clutch system, and the second connecting / disconnecting mechanism 22 shown in FIG. 3 uses a dog clutch system. Any of the clutch systems can be used for the two connection / disconnection mechanism 22, and other systems may be used. Moreover, you may provide the synchro mechanism which synchronizes the rotational speed of both the elements which disconnect and connect. Furthermore, the actuator for driving the shift shafts 104 and 172 can be any of pneumatic, hydraulic, electromagnetic, and other systems.

  FIG. 4 is an explanatory view showing a second embodiment of the driving force transmission device for a four-wheel drive vehicle according to the present invention. The configuration is the same except that the elements that connect and disconnect are different.

  In FIG. 4, the driving force transmission device 200 of this embodiment is provided in a four-wheel drive vehicle 202, and includes a driving force distribution device 204, a front wheel differential device 16, a rear wheel differential device 206, a first connecting / disconnecting mechanism 20, and A two-connection mechanism 208 is provided.

  The driving force from the engine 24 is shifted by the transmission 26 and is input to the front wheel differential device 16 from the output gear 28 of the transmission 26 via the ring gear 30, and the front wheel differential device 16 rotates inside the differential case 32. The left front wheel drive shaft 42 and the right front wheel drive shaft 44 are driven via the freely supported pinions 34, 36 and the side gears 38, 40 engaged with the pinions 34, 36, and the left front wheel drive shaft 42 and the right front wheel drive are driven. The shafts 44 respectively rotate the left front wheel 46 and the right front wheel 48 to transmit driving force to the road surface.

  Even if a rotational speed difference occurs between the left front wheel 46 and the right front wheel 54 due to cornering or changes in road surface conditions, the front wheel differential 16 absorbs the rotational speed difference and gives equal torque to the left front wheel 46 and the right front wheel 48. Can be rotated.

  The driving force input to the front wheel differential device 16 is also transmitted to the first connecting / disconnecting mechanism 20 connected to the differential case 32. When the first connecting / disconnecting mechanism 20 is connected in the four-wheel drive mode, the bevel gear 50 is connected. Then, the transmission direction of the driving force is converted by the output pinion 52 (driving force transmission direction conversion unit), and is also transmitted to the driving force distribution device 204.

  In the four-wheel drive mode, since the multi-plate clutch mechanism 60 of the driving force distribution device 204 is engaged, the driving force input to the driving force distribution device 204 is the universal joint 54, the propeller shaft 56, the universal joint 58, and the drive. It is transmitted from the pinion 62 to the rear wheel differential device 206 via the ring gear 64.

  The rear wheel differential device 206 is provided with an outer case 210 having a ring gear 64 and an inner case 212 that can be connected / disconnected by a second connecting / disconnecting mechanism 208 therein. The left rear wheel drive shaft 76 and the right rear wheel drive shaft 78 are driven via the supported pinions 68 and 70 and the side gears 72 and 74 engaged with the pinions 68 and 70, and the left rear wheel drive shaft 76 and the right rear wheel are driven. The drive shaft 78 rotates the left rear wheel 80 and the right rear wheel 82, respectively, and transmits the driving force to the road surface.

  In the four-wheel drive mode, the second connection / disconnection mechanism 208 is connected to connect the outer case 210 and the inner case 212, the outer case 210 and the inner case 212 rotate integrally, and the ring gear 64 rotates to the left rear. It is transmitted to the wheel drive shaft 76 and the right rear wheel drive shaft 78.

  Even if a difference in rotational speed occurs between the left rear wheel 80 and the right rear wheel 82 due to cornering or changes in road surface conditions, the rear wheel differential device 206 absorbs the rotational speed difference, and the left rear wheel 80 and the right rear wheel 82 Can be rotated by applying a torque equal to.

  In the four-wheel drive auto mode, the ECU 84 continuously changes the fastening force of the multi-plate clutch mechanism 60, and increases or decreases the driving force transmitted to the propeller shaft 56 as necessary. The wheel driving force distribution is controlled, and in the four-wheel drive lock mode, the multi-plate clutch mechanism 60 is held at the maximum fastening force, and the rear wheels are driven with a predetermined maximum torque.

  When the four-wheel drive mode is switched to the two-wheel drive mode, the ECU 84 first opens the multi-plate clutch mechanism 60 and then disconnects the first connection / disconnection mechanism 20 and the second connection / disconnection mechanism 208. In this case, the ECU 84 may release the multi-plate clutch mechanism 60 after first disconnecting the first connection / disconnection mechanism 20 and the second connection / disconnection mechanism 208.

  The first connecting / disconnecting mechanism 20 disconnects the differential case 32 of the front wheel differential device 16 from the bevel gear 50, and the driving force input to the ring gear 30 rotates the multi-plate clutch mechanism 60 via the output pinion 52. To prevent.

  The second connecting / disconnecting mechanism 208 disconnects the outer case 210 and the inner case 212 of the rear wheel differential device 206, and the rotational force received by the left rear wheel 80 and the right rear wheel 82 from the road surface is the ring gear 64, The drive pinion 62, the universal joint 58, the propeller shaft 56, the universal joint 54, and the multi-plate clutch mechanism 60 are prevented from rotating.

  Thus, in the two-wheel drive mode, rotation from the front and rear wheels is not transmitted to the multi-plate clutch mechanism 60, and the section from the bevel gear 50 to the outer case 210 via the multi-plate clutch mechanism 60 does not rotate. Therefore, it is possible to solve the problem that the driving force transmission path to the rear wheels rotates even when the rear wheels are not driven, which is a factor that causes a reduction in fuel consumption in the two-wheel drive mode.

  FIG. 5 is an explanatory view showing a third embodiment of the driving force transmission device for a four-wheel drive vehicle according to the present invention. The driving force distribution is compared with the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. The configuration is the same except that the position of the device and the elements to which the second connection / disconnection mechanism is connected / disconnected are different.

  In FIG. 5, the driving force transmission device 300 of this embodiment is provided in a four-wheel drive vehicle 302, and includes a driving force distribution device 304, a front wheel differential device 16, a rear wheel differential device 18, a first connecting / disconnecting mechanism 20, and Two connection mechanisms 306 and 308 are provided.

  The driving force from the engine 24 is shifted by the transmission 26 and is input to the front wheel differential device 16 from the output gear 28 of the transmission 26 via the ring gear 30, and the front wheel differential device 16 rotates inside the differential case 32. The left front wheel drive shaft 42 and the right front wheel drive shaft 44 are driven via the freely supported pinions 34, 36 and the side gears 38, 40 engaged with the pinions 34, 36, and the left front wheel drive shaft 42 and the right front wheel drive are driven. The shafts 44 respectively rotate the left front wheel 46 and the right front wheel 48 to transmit driving force to the road surface.

  Even if a rotational speed difference occurs between the left front wheel 46 and the right front wheel 54 due to cornering or changes in road surface conditions, the front wheel differential 16 absorbs the rotational speed difference and gives equal torque to the left front wheel 46 and the right front wheel 48. Can be rotated.

  The driving force input to the front wheel differential device 16 is also transmitted to the first connecting / disconnecting mechanism 20 connected to the differential case 32. When the first connecting / disconnecting mechanism 20 is connected in the four-wheel drive mode, the driving force is It is also transmitted to the distribution device 304.

  In the four-wheel drive mode, since the multi-plate clutch mechanism 60 of the driving force distribution device 304 is engaged, the driving force input to the driving force distribution device 304 changes the transmission direction of the driving force by the bevel gear 50 and the output pinion 52. Converted (driving force transmission direction changing portion), and transmitted from the universal joint 54, the propeller shaft 56, the universal joint 58, and the drive pinion 62 to the rear wheel differential 18 through the ring gear 64. The left rear wheel drive shaft 76 and the right rear wheel drive shaft 78 are driven through pinions 68 and 70 rotatably supported inside the differential case 66 and side gears 72 and 74 engaged with the pinions 68 and 70, The left rear wheel drive shaft 76 and the right rear wheel drive shaft 78 rotate the left rear wheel 80 and the right rear wheel 82, respectively, and transmit the driving force to the road surface.

  In the four-wheel drive mode, the second connecting / disconnecting mechanism 306 capable of connecting / disconnecting the left rear wheel drive shaft 76 and the left rear wheel 80 and the connection of the right rear wheel driving shaft 78 and the right rear wheel 82 can be connected / disconnected. The second connecting / disconnecting mechanism 308 is connected together, and the rotation of the left rear wheel drive shaft 76 and the right rear wheel drive shaft 78 is transmitted to the left rear wheel 80 and the right rear wheel 82 as they are.

  The second connecting / disconnecting mechanism is arranged between the rear wheel differential and the rear wheel drive shaft in the first embodiment, but in the third embodiment, the rear wheel drive shaft and the rear wheel are arranged. It is arranged between.

  Even if a difference in rotational speed occurs between the left rear wheel 80 and the right rear wheel 82 due to cornering or changes in road surface conditions, the rear wheel differential 18 absorbs the rotational speed difference, and the left rear wheel 80 and the right rear wheel 82 Can be rotated by applying a torque equal to.

  In the four-wheel drive auto mode, the ECU 84 continuously changes the fastening force of the multi-plate clutch mechanism 60, and increases or decreases the drive force transmitted to the bevel gear 50 as necessary, whereby the front and rear wheels of the drive force distribution device 304 are changed. In the four-wheel drive lock mode, the multi-plate clutch mechanism 60 is held at the maximum engagement force, and the rear wheels are driven with a predetermined maximum torque.

  When switching from the four-wheel drive mode to the two-wheel drive mode, the ECU 84 first opens the multi-plate clutch mechanism 60, and then disconnects the first connection / disconnection mechanism 20 and the second connection / disconnection mechanisms 306, 308 from each other. In this case, the ECU 84 may first release the multi-plate clutch mechanism 60 after disconnecting the connection between the first connecting / disconnecting mechanism 20 and the second connecting / disconnecting mechanisms 306, 308.

  The first connection / disconnection mechanism 20 disconnects the differential case 32 of the front wheel differential device 16 from the multi-plate clutch mechanism 60 and prevents the driving force input to the ring gear 30 from rotating the multi-plate clutch mechanism 60.

  The second connecting / disconnecting mechanism 306 disconnects the left rear wheel drive shaft 76 from the left rear wheel 80, and the second connecting / disconnecting mechanism 308 disconnects the right rear wheel drive shaft 78 from the right rear wheel 82. The rotational force received by the left rear wheel 80 and the right rear wheel 82 from the road surface is the rear wheel differential 18, the ring gear 64, the drive pinion 62, the universal joint 58, the propeller shaft 56, the universal joint 54, the output pinion 52, and the multi-plate. The clutch mechanism 60 is prevented from rotating.

  Thereby, in the two-wheel drive mode, the rotation from the front and rear wheels is not transmitted to the multi-plate clutch mechanism 60, and the section from the multi-plate clutch mechanism 60 via the propeller shaft 56 does not rotate. . Therefore, it is possible to solve the problem that the driving force transmission path to the rear wheels rotates even when the rear wheels are not driven, which is a factor that causes a reduction in fuel consumption in the two-wheel drive mode.

  In the first and second embodiments, the driving force input from the transmission 26 to the front wheel differential device 16 is transmitted in the order of the differential case 32, the bevel gear 50, the output pinion 52, and the driving force distribution device 14. The first connecting / disconnecting mechanism 20 includes a front wheel differential device 16 and a bevel gear 50 (a driving force transmission direction conversion unit) that are the most upstream of the driving force transmission path for transmitting the driving force from the engine 24 to the rear wheels 80 and 82. In the third embodiment, since the driving force is transmitted in the order of the front wheel differential device 16, the driving force distribution device 14, the bevel gear 50, and the output pinion 52 in the third embodiment, the first connection / disconnection is performed. The mechanism 20 is disposed between the front wheel differential device 16 and the driving force distribution device 14 which are the most upstream in the driving force transmission path.

  By configuring the driving force transmission devices 10, 200, and 300 in this manner, the rotation of the longest section of the driving force transmission path to the rear wheels 80 and 82 can be stopped. It is possible to minimize power loss due to friction loss of the part.

In addition, this invention is not limited to said embodiment, The appropriate deformation | transformation which does not impair the objective and advantage is included.

Explanatory drawing which shows 1st Embodiment of the driving force transmission device for four-wheel drive vehicles of this invention. Sectional drawing which shows the front wheel differential of 1st Embodiment and a 1st connection / disconnection mechanism. Sectional drawing which shows the driving force distribution apparatus, rear-wheel differential gear, and 2nd connection / disconnection mechanism of 1st Embodiment. Explanatory drawing which shows 2nd Embodiment of the driving force transmission device for four-wheel drive vehicles of this invention. Explanatory drawing which shows 3rd Embodiment of the driving force transmission device for four-wheel drive vehicles of this invention. Explanatory drawing which shows the Example of the conventional driving force transmission device for four-wheel drive vehicles

Explanation of symbols

10, 200, 300: Driving force transmission device 12, 202, 302: Four-wheel drive vehicle 14, 204, 304: Driving force distribution device 16: Front wheel differential device 18, 206: Rear wheel differential device 20: First disconnection Contact mechanism 22, 208, 306, 308: second connecting / disconnecting mechanism 24: engine 26: transmission 28: output gear 30, 64: ring gear 32, 66: differential case 34, 36, 68, 70: pinion 38, 40, 72, 74: Side gear 42: Left front wheel drive shaft 44: Right front wheel drive shaft 46: Left front wheel 48: Right front wheel 50: Bevel gear 52: Output pinion 54, 58: Universal joint 56: Propeller shaft 60: Multi-plate clutch mechanism 62: Drive pinion 76: Left rear wheel drive shaft 78: Right rear wheel drive shaft 80: Left rear wheel 82: Right rear wheel 84: ECU
86, 106: Housing 88: Pinion shaft 90, 92, 96, 98, 118, 120, 164, 166: Tapered roller bearing 94: Bevel gear shaft 100, 168: Sleeve 102, 170: Fork 104, 172: Shift shaft 108: Clutch drum 110: Clutch hub 112: Multi-plate clutch 114: Ball cam mechanism 116: Primary clutch 122, 124, 126: Ball bearing 128: Press cam plate 130: Rotating cam plate 132: Ball 134: Belleville spring 136: Thrust bearing 138: Clutch plate 140: Press plate 142: Pressure receiving plate 144: Hydraulic piston mechanism 146: Hydraulic pump 148: Servo motor 150: Hydraulic sensor 152: Press shaft 154: Thrust bearing 156: Hydraulic piston 158: Hydraulic cylinder 160: Nonion shaft 162: Side gear shaft 400: Driving force distribution device 402: Four-wheel drive vehicle 404: Engine 406: Transmission 408: Output gear 410: Ring gear 412: Front wheel differential device 414: Bevel gear 416: Output pinion 418: Propeller shaft 420: Multi-plate clutch mechanism 422: Drive pinion 424: Ring gear 426: Rear wheel differential 428: Left front wheel 430: Right front wheel 432: Left rear wheel 434: Right rear wheel

Claims (7)

A four-wheel drive mode that distributes the drive force to the front wheels and the rear wheels and a two-wheel drive mode that transmits the drive force only to the front wheels are provided. In a switchable driving force transmission device for a four-wheel drive vehicle,
A front wheel differential device that inputs a driving force from a power source and outputs the driving force to the driving force distribution device via the left and right front wheels and a driving force transmission direction converter;
A rear wheel differential device for inputting the driving force distributed by the driving force distribution device and outputting it to the left and right rear wheels;
A first connecting / disconnecting mechanism capable of disconnecting and connecting the driving force transmission between the front wheel differential device and the driving force transmission direction changing unit;
A driving force transmission device for a four-wheel drive vehicle, comprising: a second connection / disconnection mechanism capable of disconnecting and connecting the driving force transmission between the rear wheel differential device and one or both of the left and right rear wheels.
A four-wheel drive mode that distributes the drive force to the front wheels and the rear wheels and a two-wheel drive mode that transmits the drive force only to the front wheels are provided. In a switchable driving force transmission device for a four-wheel drive vehicle,
A front wheel differential device for inputting a driving force from a power source and outputting it to the left and right front wheels and the driving force distribution device;
A rear wheel differential device that inputs the driving force distributed by the driving force distribution device via the driving force transmission direction conversion unit and outputs it to the left and right rear wheels;
A first connecting / disconnecting mechanism capable of disconnecting and connecting the driving force transmission between the front wheel differential device and the driving force distribution device;
A driving force transmission device for a four-wheel drive vehicle, comprising: a second connection / disconnection mechanism capable of disconnecting and connecting the driving force transmission between the rear wheel differential device and one or both of the left and right rear wheels.
In the driving force transmission device for a four-wheel drive vehicle according to claim 1 or 2,
In the four-wheel drive mode, the first connecting / disconnecting mechanism and the second connecting / disconnecting mechanism are connected, and the driving force distribution of the driving force distribution device is controlled in accordance with a traveling condition,
In the two-wheel drive mode, the driving force transmission device for a four-wheel drive vehicle is characterized in that the first connecting / disconnecting mechanism and the second connecting / disconnecting mechanism are disconnected.
In the driving force transmission device for a four-wheel drive vehicle according to claims 1 to 3,
The rear wheel differential device includes a first output element and a second output element that output driving force to the rear wheel,
The driving force transmission device for a four-wheel drive vehicle, wherein the second connecting / disconnecting mechanism is capable of cutting and connecting driving force transmission between the rear wheel and the first output element.
In the driving force transmission device for a four-wheel drive vehicle according to claims 1 to 3,
The rear wheel differential device includes a first output element and a second output element that output driving force to the rear wheel,
A driving force transmission device for a four-wheel drive vehicle, wherein the second connecting / disconnecting mechanism is capable of cutting and connecting driving force transmission between the rear wheel, the first output element, and the second output element.
In the driving force transmission device for a four-wheel drive vehicle according to claims 1 to 3,
The rear wheel differential device includes an input element that inputs driving force from the driving force distribution device, and an output element that outputs driving force to the rear wheel,
The second connecting / disconnecting mechanism is capable of disconnecting and connecting driving force transmission between the input element and the output element.
The driving force transmission device for a four-wheel drive vehicle according to any one of claims 1 to 6, wherein the driving force distribution device includes:
A driving force transmission device for a four-wheel drive vehicle characterized by controlling the distribution of the driving force transmitted to the front wheels and the rear wheels by continuously changing the fastening force of the multi-plate clutch mechanism.

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