JP2019177710A - Transfer of all wheels drive vehicle - Google Patents

Abstract

To provide a transfer of all wheels drive vehicle capable of enhancing fuel consumption by resolving dragging torque generated when a clutch is released while restraining rise in cost.SOLUTION: A transfer 1 comprises a first rear drive shaft 30a of which one end part is connected to output side of a transfer clutch 20, a second rear drive shaft 30b which is provided coaxially with the first rear drive shaft 30a and is formed with an outer spline 32 on the one end part, a connecting and disconnecting mechanism 40 which interposes between the first rear drive shaft 30a and the second rear drive shaft 30b and disconnects the connection of the first rear drive shaft 30a with the second rear drive shaft 30b in accordance with supplied hydraulic pressure and a TCU 70 which controls the hydraulic pressure so as to release the connecting and disconnecting mechanism 40 when releasing the transfer clutch 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an all-wheel drive vehicle transfer, and more particularly to an all-wheel drive vehicle transfer having a multi-plate clutch.

  Conventionally, an all-wheel drive (AWD) vehicle (or a four-wheel drive (or four-wheel drive)) that has excellent running performance on steep slopes, rough roads with many bumps, and slippery road surfaces (for example, snow roads and mud roads). 4WD) vehicles) are widely used. An all-wheel drive vehicle has, for example, main drive wheels that are directly connected to the engine and auxiliary drive wheels that are connected to the engine via a transfer clutch. There is a configuration that switches between two-wheel drive and all-wheel drive by adjusting the driving force distribution to the auxiliary drive wheel side by controlling accordingly.

  Here, in Patent Document 1, when the driving mode is not the fuel consumption appeal mode, the driving force distribution of the front and rear wheels is optimally controlled in accordance with the motion state of the vehicle by controlling the fastening force of the transfer clutch (wet multi-plate clutch). In the fuel consumption promotion mode, whether or not slip is detected is checked. If no slip is detected, the transfer clutch is released and the driving force to the front wheels is set to 100. % If the front wheel drive is controlled and slip is detected, the transfer clutch is set to the engaged state and standby AWD control is executed to alleviate the slip at an early stage. A control device is disclosed.

JP 2012-116433 A

  According to the driving force distribution control device for an all-wheel drive vehicle disclosed in Patent Document 1 described above, the effect of the fuel consumption appeal mode can be further improved. However, in the above-described configuration, when the transfer clutch (wet multi-plate clutch) is released, friction torque, that is, drag torque (drag torque) is generated due to rotation of the transfer clutch. Therefore, there is a possibility that improvement of the fuel consumption rate (hereinafter referred to as “fuel consumption”) may be hindered. On the other hand, in order to solve such a problem, for example, if an electric actuator or an electronic control coupling is used instead of / in addition to the transfer clutch (wet multi-plate clutch), the cost increases.

  The present invention has been made to solve the above problems, and in an all-wheel drive (AWD) vehicle transfer having a multi-plate clutch, the drag torque at the time of clutch release is eliminated while suppressing an increase in cost. An object of the present invention is to provide a transfer for an all-wheel drive vehicle capable of improving fuel efficiency.

  The transfer of the all-wheel drive vehicle according to the present invention has a multi-plate clutch, adjusts the torque input from the transmission according to the supplied hydraulic pressure, and outputs to the auxiliary drive wheel side, A first shaft having one end connected to the output side of the transfer clutch, a second shaft provided coaxially with the first shaft, and having a spline formed at one end, the first shaft and the second shaft The connection / disconnection mechanism for connecting / disconnecting the first shaft and the second shaft, and the hydraulic pressure supplied to each of the transfer clutch and the connection / disconnection mechanism are controlled according to the supplied hydraulic pressure. And a connecting / disconnecting mechanism formed with a spline that can be fitted to the spline formed on the second shaft, is rotatable integrally with the first shaft, and is adapted to the supplied hydraulic pressure. The first shaft and the second shaft are slidable in the axial direction, and when the hydraulic control means releases the transfer clutch, the hydraulic pressure is controlled so as to release the connection / disconnection mechanism. It is characterized by controlling.

  According to the all-wheel-drive vehicle transfer of the present invention, when the transfer clutch is released, the hydraulic pressure is controlled so that the sleeve is slid in the axial direction to release the connection / disconnection mechanism. Therefore, when the transfer clutch (multi-plate clutch) is released, the connecting / disconnecting mechanism is released, and the first shaft and the second shaft (that is, the transfer clutch and the drive system on the auxiliary drive wheel side) are disconnected. This eliminates the drag torque of the transfer clutch. Therefore, fuel consumption can be improved. On the other hand, the connection / disconnection mechanism can be realized with a relatively simple configuration, that is, at a relatively low cost. As a result, it is possible to improve fuel efficiency by eliminating drag torque when the clutch is released while suppressing an increase in cost.

  In the transfer for an all-wheel drive vehicle according to the present invention, a spline is formed at the other end of the first shaft, and the connecting / disconnecting mechanism has a spline that is always fitted with the spline formed on the first shaft. It is preferable to have.

  In this way, the connection / disconnection mechanism (sleeve) can be rotated integrally with the first shaft and slidable in the axial direction of the first shaft and the second shaft.

  In the transfer for an all-wheel drive vehicle according to the present invention, the hydraulic control means passes through a common hydraulic circuit communicating with each of the oil chamber that applies hydraulic pressure to the transfer clutch and the oil chamber that applies hydraulic pressure to the connection / disconnection mechanism. It is preferable to release the transfer clutch and release the connection / disengagement mechanism by discharging the hydraulic pressure while fastening the transfer clutch and the connection / disconnection mechanism by supplying the pressure.

  In this way, the engagement / release of the transfer clutch and the connection / disconnection mechanism can be controlled using the common hydraulic circuit and the common hydraulic pressure. That is, it is not necessary to newly add a dedicated hydraulic circuit (hydraulic piping), a hydraulic valve for hydraulic control, and the like, and an increase in cost can be suppressed.

  In the all-wheel-drive vehicle transfer according to the present invention, it is preferable that a synchronization mechanism is provided between the sleeve and the spline formed on the second shaft to synchronize both rotations when engaged.

  In this way, even when the sleeve (connection / disconnection mechanism) and the spline (second shaft) have different rotational speeds when the sleeve and the spline formed on the second shaft are engaged, smoother. The sleeve and the spline can be engaged, that is, the connection / disconnection mechanism can be fastened.

  In the transfer for an all-wheel drive vehicle according to the present invention, when the hydraulic pressure is supplied and the transfer clutch and the connection / disconnection mechanism are engaged, the transfer clutch is preferably engaged after the synchro mechanism is engaged. .

  In this way, when the synchro mechanism is engaged (the connecting / disconnecting mechanism is fastened), the inertia is small because the transfer clutch is not yet fastened (that is, the transmission or the like is not connected). Therefore, the inertia can be easily absorbed (that is, the lack of torque capacity of the synchro mechanism can be avoided).

  In the transfer of the all-wheel drive vehicle according to the present invention, when the hydraulic pressure is discharged and the transfer clutch and the connection / disconnection mechanism are released, it is preferable that the connection / disconnection mechanism is released after the transfer clutch is released. .

  In this way, when the connection / disengagement mechanism is released, the transfer clutch is already disengaged and the input torque from the transmission side is lost, so the sleeve can be easily pulled out (that is, the connection / disconnection mechanism is released). can do.

  The transfer of the all-wheel drive vehicle according to the present invention provides a first return spring that applies a biasing force to the transfer clutch in a direction to release the transfer clutch, and a biasing force to the connection / disconnection mechanism in a direction to release the connection / disconnection mechanism. It is preferable that the biasing force of the first return spring is set larger than the biasing force of the second return spring.

  In this way, when the transfer clutch and the connection / disconnection mechanism are engaged, the transfer clutch can be engaged after the synchro mechanism is engaged (the connection / disconnection mechanism is engaged). Further, when the transfer clutch and the connection / disconnection mechanism are released, the connection / disconnection mechanism can be released after the transfer clutch is released.

  In the transfer for an all-wheel drive vehicle according to the present invention, it is preferable that the pressure receiving area of the oil chamber that applies hydraulic pressure to the transfer clutch is set smaller than the pressure receiving area of the oil chamber that applies hydraulic pressure to the connection / disconnection mechanism.

  Even in this case, when the transfer clutch and the connection / disconnection mechanism are engaged, the transfer clutch can be engaged after the synchro mechanism is engaged (the connection / disconnection mechanism is engaged). Further, when the transfer clutch and the connection / disconnection mechanism are released, the connection / disconnection mechanism can be released after the transfer clutch is released.

  According to the present invention, in the transfer of an all-wheel drive (AWD) vehicle having a multi-plate clutch, it is possible to improve the fuel consumption by eliminating the drag torque when the clutch is released while suppressing an increase in cost.

It is sectional drawing which shows the structure of the transfer which concerns on embodiment. It is a flowchart which shows the flow at the time of fastening a transfer clutch and a connection / disconnection mechanism. It is a flowchart which shows the flow at the time of releasing a transfer clutch and a connection / disconnection mechanism.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals are used for the same or corresponding parts. Moreover, in each figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.

  First, the structure of the transfer 1 of the all-wheel drive vehicle which concerns on embodiment is demonstrated using FIG. FIG. 1 is a cross-sectional view showing the configuration of the transfer 1.

  The transfer 1 mainly includes a transfer shaft 10, a rear drive shaft 30 disposed coaxially with the transfer shaft 10, a transfer clutch 20 interposed between the transfer shaft 10 and the rear drive shaft 30, and a rear drive The connecting / disconnecting mechanism 40 provided between the first rear drive shaft 30a and the second rear drive shaft 30b constituting the shaft 30 is provided. Hereinafter, each component will be described in detail.

  A counter driven gear 11 is integrally formed on the outer periphery of the transfer shaft 10. Torque (that is, driving force converted by the transmission) is input to the transfer shaft 10 from a transmission such as a continuously variable transmission (CVT) or a step AT (stepped automatic transmission) through the counter driven gear 11. Is done.

  Behind the transfer shaft 10 are a first rear drive shaft 30a (corresponding to the first shaft described in claims) and a second rear drive shaft 30b (corresponding to the second shaft described in claims). A rear drive shaft 30 is arranged on the same axis. The transfer shaft 10 and the rear drive shaft 30 are configured to be rotatable with respect to each other via a needle bearing. The rear drive shaft 30 is connected to a rear differential (not shown) via a propeller shaft (not shown) or the like, and receives a torque input from the transmission and adjusted by the transfer clutch 20 as a rear wheel (sub drive). To the wheel side.

  A transfer clutch 20 is provided between the transfer shaft 10 and the rear drive shaft 30 (first rear drive shaft 30a) on the torque transmission path. The transfer clutch 20 has a wet multi-plate clutch configured by alternately stacking a drive plate 20a provided on the transfer shaft 10 side and a driven plate 20b provided on the rear drive shaft 30 side.

  A drum 21 having a driven plate 20b attached to the inner peripheral surface is provided at one end of the first rear drive shaft 30a (for example, joined by welding). A transfer piston 22 whose end is in contact with the driven plate 20b is disposed inside the drum 21. An oil chamber 23 is defined by the drum 21 and the transfer piston 22.

  The transfer piston 22 is provided so as to be slidable in the axial direction of the rear drive shaft 30, and has a pressing force corresponding to the hydraulic pressure supplied to the oil chamber 23 (that is, the hydraulic pressure and the pressure receiving area (surface perpendicular to the axial line). Is applied to the transfer clutch 20 (driven plate 20b). Further, the transfer piston 22 is provided with a first return spring 24 that applies an urging force to the transfer piston 22 (transfer clutch 20) in a direction in which the transfer clutch 20 is released (rightward in the drawing).

  The transfer clutch 20 adjusts the torque output to the rear drive shaft 30 (that is, the rear wheel side) according to the hydraulic pressure supplied to the oil chamber 23. More specifically, by controlling the hydraulic pressure supplied to the oil chamber 23, that is, the pressing force by the transfer piston 22, the fastening force of the transfer clutch 20 is adjusted, and the front wheel (main drive wheel) and the rear wheel (sub drive) are adjusted. For example, the torque distribution ratio with the wheel) is varied between 100: 0 and 50:50. The hydraulic pressure supplied to the transfer clutch 20 (oil chamber 23) is adjusted by an electronic control unit (hereinafter referred to as “TCU”) 70 and a control valve 71 which will be described later.

  Between the first rear drive shaft 30a and the second rear drive shaft 30b constituting the rear drive shaft 30, there is a connection / disconnection mechanism 40 for intermittently connecting the first rear drive shaft 30a and the second rear drive shaft 30b. Is provided. An outer spline 31 is formed at the other end of the first rear drive shaft 30a so as to extend in the axial direction. An outer spline 32 is formed at one end of the second rear drive shaft 30b so as to extend in the axial direction.

  The connection / disconnection mechanism 40 mainly includes a sleeve piston 42, a sleeve 43, and an oil chamber 44. The sleeve piston 42 is formed in a substantially bottomed cylindrical shape in which a through hole through which the first rear drive shaft 30a passes is formed at the bottom. The sleeve piston 42 is disposed at the other end of the first rear drive shaft 30a so that the first rear drive shaft 30a passes through the center thereof, that is, coaxially with the first rear drive shaft 30a. An inner spline 46 is formed on the inner peripheral surface of the sleeve piston 42 so as to extend in the axial direction. The inner spline 46 is arranged so as to always mesh with the outer spline 31 of the first rear drive shaft 30a. Therefore, the sleeve piston 42 is slidable in the axial direction of the first rear drive shaft 30a while rotating integrally with the first rear drive shaft 30a.

  A cylindrical sleeve 43 is connected to the end of the sleeve piston 42. The sleeve piston 42 and the sleeve 43 may be joined together by welding or the like, for example, or may be integrally formed. A spline 47 that can be fitted to the outer spline 32 formed at one end of the second rear drive shaft 30b is formed at the end of the sleeve 43 so as to extend in the axial direction. A chamfer with a chamfered edge is formed at the tip of the spline 47.

  The sleeve piston 42 is disposed inside a cylinder 41 (for example, joined by welding or the like) provided at the other end of the first rear drive shaft 30a. An oil chamber 44 is defined by the cylinder 41 and the bottom surface of the sleeve piston 42. The sleeve piston 42 and the sleeve 43 are provided so as to be slidable in the axial direction of the first rear drive shaft 30a, and the pressing force corresponding to the hydraulic pressure supplied to the oil chamber 44 (that is, the hydraulic pressure and the pressure receiving area (on the axial line) On the other hand, it slides in the axial direction under a pressing force determined by a multiplication value of the area of the surface perpendicular to the surface. As a result, the spline 47 formed on the sleeve 43 is movable to a position where it engages with the outer spline 32 formed on the second rear drive shaft 30b and a position where it disengages. The sleeve piston 42 is provided with a second return spring 45 that applies an urging force to the sleeve piston 42 in a direction in which the connection / disconnection mechanism 40 is released (left direction in the drawing).

  Further, a synchro mechanism 51 (synchronizer ring) is provided between the sleeve 43 and the outer spline 32 formed on the second rear drive shaft 30b to synchronize both rotations when engaged (when connected). Yes. A spline that meshes with the sleeve 43 is provided on the outer periphery of the synchro mechanism 51. A chamfer with a chamfered edge is also formed at the tip of the spline.

  The connection / disconnection mechanism 40 is controlled to be engaged / released in accordance with the hydraulic pressure supplied to the oil chamber 44, and connects / disconnects the first rear drive shaft 30a and the second rear drive shaft 30b. Therefore, the connection / disconnection mechanism 40 can be engaged / released by controlling the hydraulic pressure supplied to the oil chamber 44, that is, the pressing force by the sleeve piston 42. More specifically, when the hydraulic pressure is supplied, the sleeve piston 42 and the sleeve 43 slide in the axial direction (right direction in the drawing), and the connection / disconnection mechanism 40 is fastened. On the other hand, when the hydraulic pressure is discharged, the connection / disconnection mechanism 40 is released by the urging force of the second return spring 45. The hydraulic pressure supplied to the connection / disconnection mechanism 40 (oil chamber 44) is also adjusted by a TCU 70 and a control valve 71 described later.

  Here, the biasing force of the first return spring 24 described above is set larger than the biasing force of the second return spring 45. Therefore, when the hydraulic pressure is supplied and the transfer clutch 20 and the connection / disconnection mechanism 40 are engaged, the transfer clutch 20 is engaged after the synchro mechanism 51 is engaged (the connection / disconnection mechanism 40 is engaged). On the other hand, when the hydraulic pressure is discharged and the transfer clutch 20 and the connection / disconnection mechanism 40 are released, the connection / disconnection mechanism 40 is released after the transfer clutch 20 is released.

  Instead of or in addition to setting the biasing force of the return spring, the pressure receiving area of the oil chamber 23 (transfer piston 22) that applies hydraulic pressure to the transfer clutch 20 is applied, and the hydraulic pressure is applied to the sleeve piston 42 (sleeve 43). The pressure receiving area of the oil chamber 44 (sleeve piston 42) may be set smaller.

  As described above, the hydraulic pressure supplied to the oil chamber 23 of the transfer clutch 20 and the oil chamber 44 of the connection / disconnection mechanism 40 is controlled by the TCU 70 and the control valve 71. The TCU 70 and the control valve 71 function as hydraulic control means described in the claims. The TCU 70 includes a microprocessor that performs calculations, an EEPROM that stores programs for causing the microprocessor to execute each process, a RAM that stores various data such as calculation results, a backup RAM that holds the stored contents, and an input It has an output I / F and the like.

  The TCU 70 determines the engagement force of the transfer clutch 20 (that is, the driving force distribution ratio to the rear wheels) based on various information (for example, the driving state of the four wheels, the engine torque, etc.) indicating the driving state of the vehicle acquired from various sensors. ) In real time. At this time, the TCU 70 controls the drive of the solenoid valve that constitutes the control valve 71 to adjust the hydraulic pressure supplied to the transfer clutch 20 and adjust the distribution ratio of the driving force transmitted to the rear wheels. The control valve 71 adjusts the hydraulic pressure discharged from the oil pump by opening and closing an oil passage formed in the control valve 71 using a spool valve and a solenoid valve that moves the spool valve, so that the transfer clutch 20 Supply hydraulic pressure to engage / release the clutch.

  Further, the TCU 70 and the control valve 71 control the hydraulic pressure so as to release the connection / disconnection mechanism 40 when the transfer clutch 20 is released. The TCU 70 and the control valve 71 supply hydraulic pressure through a common hydraulic circuit 72 that communicates with the oil chamber 23 that applies hydraulic pressure to the transfer clutch 20 and the oil chamber 44 that applies hydraulic pressure to the connection and disconnection mechanism 40. While the transfer clutch 20 is fastened and the connection / disconnection mechanism 40 is fastened, the transfer clutch 20 is released and the connection / disconnection mechanism 40 is released by discharging the hydraulic pressure.

  Next, the operation of the transfer 1 will be described with reference to FIGS. 2 and 3 together. FIG. 2 is a flowchart showing a flow when the transfer clutch 20 and the connection / disconnection mechanism 40 are engaged. FIG. 3 is a flowchart showing a flow when releasing the transfer clutch 20 and the connection / disconnection mechanism 40.

  First, a sequence when the transfer clutch 20 and the connection / disconnection mechanism 40 are fastened will be described with reference to FIG. In step S100, the hydraulic pressure supplied to the transfer clutch 20 and the connection / disconnection mechanism 40 is increased. In step S102, the synchro mechanism 51 is first engaged and the connection / disconnection mechanism 40 is fastened due to the increase in hydraulic pressure. More specifically, the sleeve 43 slides in the axial direction together with the sleeve piston 42 and is pushed out to the right side of the drawing. Then, after the rotation is synchronized by the synchro mechanism 51, the sleeve 43 (spline 47) is fitted to the outer spline 32 formed on the second rear drive shaft 30b.

  Subsequently, in step S104, the hydraulic pressure supplied to the transfer clutch 20 and the connection / disconnection mechanism 40 is further increased. In step S106, the transfer clutch 20 is engaged. Thus, when the transfer clutch 20 and the connection / disconnection mechanism 40 are fastened, the transfer clutch 20 is fastened after the synchro mechanism 51 is engaged (the connection / disconnection mechanism 40 is fastened).

  Next, a sequence for releasing the transfer clutch 20 and the connection / disconnection mechanism 40 will be described with reference to FIG. First, in step S200, the hydraulic pressure supplied to the transfer clutch 20 and the connection / disconnection mechanism 40 is reduced. Therefore, in step S202, the transfer clutch 20 is released by the urging force of the first return spring 24. Subsequently, in step S204, the hydraulic pressure supplied to the transfer clutch 20 and the connection / disconnection mechanism 40 is further reduced. Therefore, in step S206, the connection / disconnection mechanism 40 is released by the urging force of the second return spring 45. In this way, when the transfer clutch 20 and the connection / disconnection mechanism 40 are released, the connection / disconnection mechanism 40 is released after the transfer clutch 20 is released.

  As described above in detail, according to the present embodiment, when the transfer clutch 20 is released, the hydraulic pressure is controlled so that the sleeve 43 is slid in the axial direction and the connection / disconnection mechanism 40 is released. Is done. Therefore, when the transfer clutch 20 is released, the connection / disconnection mechanism 40 is released, and the first rear drive shaft 30a and the second rear drive shaft 30b (that is, the drive system on the transfer clutch 20 and the auxiliary drive wheel side). Is disconnected, the drag torque of the transfer clutch 20 is eliminated. Therefore, fuel consumption can be improved. On the other hand, the connection / disconnection mechanism 40 (dog clutch) can be realized with a relatively simple configuration, that is, at a relatively low cost. As a result, it is possible to improve fuel efficiency by eliminating drag torque when the transfer clutch 20 is released while suppressing an increase in cost.

  According to this embodiment, the engagement / release of the transfer clutch 20 and the connection / disconnection mechanism 40 can be controlled using the common hydraulic circuit 72 and the common hydraulic pressure. That is, it is not necessary to newly add a dedicated hydraulic circuit (hydraulic piping), a hydraulic valve for hydraulic control, and the like, and an increase in cost can be suppressed.

  According to the present embodiment, since the synchro mechanism 51 that synchronizes the rotation of both the sleeve 43 and the outer spline 32 formed on the second rear drive shaft 30b is provided when engaged, Even when the rotational speeds of the sleeve 43 (connection / disconnection mechanism 40) and the outer spline 32 (second rear drive shaft 30b) are different from each other when engaged with the outer spline 32, the sleeve 43 and the outer spline can be smoother. 32, that is, the connection / disconnection mechanism 40 can be fastened.

  According to the present embodiment, when the hydraulic pressure is supplied and the transfer clutch 20 and the connection / disconnection mechanism 40 are engaged, the transfer clutch 20 is engaged after the synchro mechanism 51 is engaged (the connection / disconnection mechanism 40 is engaged). Is done. Therefore, when the synchro mechanism 51 is engaged, the inertia is small because the transfer clutch 20 is not yet engaged (that is, the transmission or the like is not connected). Therefore, the inertia can be easily absorbed (that is, the lack of torque capacity of the synchro mechanism 51 can be avoided).

  According to the present embodiment, when the hydraulic pressure is discharged and the transfer clutch 20 and the connection / disconnection mechanism 40 are released, the connection / disconnection mechanism 40 is released after the transfer clutch 20 is released. Therefore, when the connecting / disconnecting mechanism 40 is released, the transfer clutch 20 is already released and the input torque from the transmission side is eliminated, so that the sleeve 43 can be easily pulled out (that is, the connecting / disconnecting mechanism 40 is released). can do.

  According to the present embodiment, the urging force of the first return spring 24 that applies the urging force in the direction of releasing the transfer clutch 20 has the second return spring 45 that applies the urging force in the direction of releasing the connection / disconnection mechanism 40. It is set larger than the urging force. Therefore, when the transfer clutch 20 and the connection / disconnection mechanism 40 are engaged, the transfer clutch 20 can be engaged after the synchro mechanism 51 is engaged (the connection / disconnection mechanism 40 is engaged). Further, when the transfer clutch 20 and the connection / disconnection mechanism 40 are released, the connection / disconnection mechanism 40 can be released after the transfer clutch 20 is released.

  Note that, according to the present embodiment, the pressure receiving area of the oil chamber 23 that applies the hydraulic pressure to the transfer clutch 20 is set to be smaller than the pressure receiving area of the oil chamber 44 that applies the hydraulic pressure to the connection / disconnection mechanism 40. After the mechanism 51 is engaged (the connection / disconnection mechanism 40 is fastened), the transfer clutch 20 can be fastened. Further, after the transfer clutch 20 is released, the connection / disconnection mechanism 40 can be released.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, the first rear drive shaft 30a and the second rear drive shaft 30b are configured to be intermittent, but in addition to the above configuration, for example, a propeller shaft and a rear wheel (sub drive wheel) It is good also as a structure which can provide a connection mechanism in between and can isolate | separate both.

  Further, the form of the all-wheel drive vehicle (AWD) is not limited to the above-described embodiment, and the present invention can also be applied to other forms of all-wheel drive vehicles.

  Furthermore, the configuration of the connection / disconnection mechanism 40 is not limited to the above-described embodiment, and a configuration without the inner spline 46 of the sleeve piston 42 may be employed. That is, the spline 47 formed on the sleeve 43 slides in the axial direction while always meshing with the outer spline 31 of the first rear drive shaft 30a (that is, the outer spline 32 formed on the second rear drive shaft 30b). It is also possible to adopt a configuration in which the second rear drive shaft 30b (outer spline 32) can be connected to and disconnected from the position where it engages with and the position where the engagement disengages.

DESCRIPTION OF SYMBOLS 1 Transfer 10 Transfer shaft 20 Transfer clutch 20a Drive plate 20b Driven plate 21 Drum 22 Transfer piston 23 Oil chamber 24 1st return spring 30 Rear drive shaft 30a 1st rear drive shaft 30b 2nd rear drive shaft 31 Outer spline 32 Outer spline 40 Connection mechanism 41 Cylinder 42 Sleeve piston 43 Sleeve 44 Oil chamber 45 Second return spring 46 Inner spline 47 Spline 51 Synchro mechanism 70 TCU
71 Control valve 72 Hydraulic circuit

Claims (8)

A transfer clutch that has a multi-plate clutch, adjusts the torque input from the transmission according to the supplied hydraulic pressure, and outputs it to the auxiliary drive wheel side;
A first shaft having one end connected to the output side of the transfer clutch;
A second shaft provided coaxially with the first shaft and having a spline formed at one end thereof;
A connecting / disconnecting mechanism for connecting / disconnecting the first shaft and the second shaft according to a hydraulic pressure which is interposed between the first shaft and the second shaft;
A hydraulic control means for controlling the hydraulic pressure supplied to each of the transfer clutch and the connection / disconnection mechanism;
The connection / disconnection mechanism includes a spline that can be fitted to a spline formed on the second shaft, can rotate integrally with the first shaft, and can be rotated according to a supplied hydraulic pressure. And a sleeve provided slidably in the axial direction of the second shaft,
The transfer of an all-wheel drive vehicle, wherein the hydraulic control means controls the hydraulic pressure so as to release the connection / disconnection mechanism when the transfer clutch is released. The first shaft has a spline at the other end,
The transfer of an all-wheel drive vehicle according to claim 1, wherein the connection / disconnection mechanism has a spline that is always spline-fitted with a spline formed on the first shaft. The hydraulic control means, through a common hydraulic circuit that communicates with an oil chamber that applies hydraulic pressure to the transfer clutch, and an oil chamber that applies hydraulic pressure to the connection and disconnection mechanism,
By supplying hydraulic pressure, the transfer clutch is fastened and the connection / disconnection mechanism is fastened,
The transfer of an all-wheel drive vehicle according to claim 1 or 2, wherein the transfer clutch is released and the connecting / disconnecting mechanism is released by discharging hydraulic pressure.   The synchro mechanism which synchronizes both rotations at the time of engagement is provided between the sleeve and the spline formed on the second shaft. All-wheel drive transfer as described.   5. The transfer clutch according to claim 4, wherein when the hydraulic clutch is supplied and the transfer clutch and the connection / disconnection mechanism are engaged, the transfer clutch is engaged after the synchro mechanism is engaged. All-wheel drive car transfer.   6. The connecting / disconnecting mechanism is released after the transfer clutch is released when hydraulic pressure is discharged and the transfer clutch and the connecting / disconnecting mechanism are released. All-wheel drive transfer as described. A first return spring that applies a biasing force to the transfer clutch in a direction to release the transfer clutch;
A second return spring for applying a biasing force to the connection / disconnection mechanism in a direction to release the connection / disconnection mechanism;
The transfer of an all-wheel drive vehicle according to claim 5 or 6, wherein an urging force of the first return spring is set larger than an urging force of the second return spring.   The pressure receiving area of the oil chamber that applies hydraulic pressure to the transfer clutch is set smaller than the pressure receiving area of the oil chamber that applies hydraulic pressure to the connection / disconnection mechanism. Transfer of all-wheel drive vehicle as described in the item.

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