JPH1029438A - Transfer device of four-wheel drive vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make improvements in controllability lying between 2WD and 4WD by operating a clutch in time of the two-wheel drive where connection by a coupling means is released, and prohibiting any differential motion of a differential mechanism, while in time of the four-wheel drive, making a driving force distribution to both front and rear wheels variable upon operating the clutch properly. SOLUTION: An engine 2 is connected to an input shaft 8 of a transfer device 5 for 4WD use via a transmission 4, but in this case, an intermediate shaft 36 to be situated axially with this input shaft is connected to an output shaft 10 at the rear-wheel side via a center differential gear 62. Two clutch gears 74 and 78 are attached to respective ends of both inner and outer sleeve shafts 72 and 76 of the center differential gear 62, and another clutch gear 80 to the intermediate shaft 36 so as to pinch the clutch 74, respectively. In addition, a coupling sleeve 82 as a coupling means is engaged with both the clutch gears 74 and 78, making it into full-time 4WD, and it is engaged with these clutch gears 74 and 80, making it into 2WD respectively, and when it is engaged with all the clutch gears 74, 78 and 80, a direct four-wheel drive system is securable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device for a four-wheel drive vehicle in which both front wheels and rear wheels are driven.

[0002]

2. Related Background Art A transfer device of this type is disclosed in, for example, Japanese Patent Publication No. 8-25402. This known transfer device includes a center differential that distributes and transmits power from a transmission to front wheels and rear wheels. And a viscous coupling for limiting a differential between the front wheel output shaft and the rear wheel output shaft. In addition, the drive mode of the known transfer device can be switched between full-time four-wheel drive, two-wheel drive and direct-coupled four-wheel drive via a switching mechanism.

[0003]

In the above-described transfer device, the viscous coupling is disposed between the front wheel output shaft and the rear wheel output shaft. The driving force is transmitted to the front wheels via the viscous coupling only when the driving force is generated. Therefore, even if an emergency avoidance operation of the vehicle is performed in a state where there is no difference in rotational speed between the front and rear wheels, the driving force cannot be transmitted to the front wheels, and sufficient running stability is secured. Can not.

Further, since the switching mechanism of the known transfer device does not include a synchronizing device, the sleeve of the switching mechanism does not smoothly mesh with the spline to be coupled, and the sliding of the sleeve is not easy. The present invention has been made based on the above-described circumstances, and a main object of the present invention is to provide a transfer device for a four-wheel drive vehicle having excellent controllability when switching between two-wheel drive and four-wheel drive. It is in. A further object of the present invention is to provide a transfer device for a four-wheel drive vehicle that can also improve running performance during four-wheel drive.

[0005]

The above object has been achieved by the present invention, and a transfer device for a four-wheel drive vehicle according to claim 1 receives power from a power generation device at an input element, and receives power from a front wheel side and a rear wheel side. A differential mechanism that transmits the power at different distribution ratios to the wheel side output elements and allows a differential between the front wheel side and rear wheel side output elements, and one of the front wheel side and rear wheel side output elements and First connecting means for intermittently connecting a wheel-side member transmitting power to a corresponding wheel, and a first connecting means provided between two of the front-wheel-side output element, the rear-wheel-side output element, and the input element; And clutch means for controlling the rotational differential between these two elements.

According to the first aspect of the present invention, in the two-wheel drive in which the connection by the first connecting means is released, the differential of the differential mechanism is inhibited by operating the clutch means, and the driving wheels are driven. The driving force is reliably transmitted. Further, at the time of four-wheel drive in which the connection by the first connection means is established,
When the clutch means is operated as appropriate, the distribution of the driving force to the front and rear wheels is varied, and the optimum distribution of the driving force is set according to the running state.

According to a second aspect of the present invention, there is provided a transfer device which receives power from a power generating device at an input element, transmits power to a front wheel side and rear wheel side output element, respectively, and generates a difference between the front wheel side and rear wheel side output element. A differential mechanism that permits movement, and a first mechanism that connects and disconnects any one of the front-wheel-side and rear-wheel-side output elements and a wheel-side member that transmits power toward the corresponding wheel.
The vehicle includes a coupling means and a clutch means for intermittently connecting the other of the front wheel side and rear wheel side output elements or the input element and the wheel side member.

As a preferred mode of control using the transfer device according to the second aspect, it is conceivable that the connection by the clutch means is performed even during the two-wheel drive in which the connection by the first connection means is released. By doing so, it is possible to shift to four-wheel drive traveling even during traveling with two-wheel drive.
Further, as another preferable control mode, when the coupling and disconnection are performed by the first coupling means, that is, when switching between the two-wheel drive and the four-wheel drive, when the clutch means is used as a synchronization device, The front wheel side or rear end side output element connected to the wheel side member can be synchronized, and the drive mode can be switched smoothly.

Further, as another preferable control mode,
By controlling the clutch means during the four-wheel drive in which the connection by the first connection means is established, the differential rotation of the differential mechanism is limited. In the differential mechanism of the transfer device according to the third aspect, power is transmitted to the front wheel side and rear wheel side output elements at different distribution ratios. By variably controlling the coupling of the clutch means, the driving force distribution is varied,
The optimal driving force distribution is set according to the running state.

According to a fourth aspect of the present invention, the transfer apparatus further includes a second connecting means for connecting and disconnecting two of the input element, the front wheel side output element and the rear wheel side output element. If the connection by the second connecting means is established, the differential mechanism is securely locked without operating the clutch means, and does not consume the energy required for connecting the clutch means.

When the coupling and disconnection are performed by the second coupling means, that is, when the differential mechanism is switched between the locked state and the unlocked state, the clutch means may be used as a synchronizing device. Since the two elements connected by the second connecting means can be synchronized, the switching by the second connecting means can be performed smoothly.

Preferably, if the first connecting means and the second connecting means are realized by the same member, a compact configuration is obtained.

[0013]

1 and 2, there is shown schematically a four-wheel drive vehicle of the front engine rear wheel drive (FR) type. This vehicle includes an engine 2, and the engine 2 is connected to a transfer device 6 for 4WD via a transmission 4, that is, an input shaft 8 of the transfer device 6. Although the details of the transfer device 6 will be described later, the transfer device 6 includes a rear wheel output shaft 10 and a front wheel transfer sprocket 12 to which the driving force of the input shaft 8 is transmitted. It is connected to a rear wheel differential device (rear wheel differential) 14 via a rear propeller shaft. A pair of left and right rear axles extend from the rear wheel differential 14, and left and right rear wheels RW are connected to these rear axles, respectively. On the other hand, a front propeller shaft 16 extends from the transfer sprocket 12, and the front propeller shaft 16 is connected to a front wheel differential device (front wheel differential) 18. A pair of left and right front axles extend from the front wheel differential 18, and the left and right front wheels FW are attached to these front axles.
Are connected respectively.

As shown in FIG. 1, the right front axle is divided in the middle thereof, and clutch gears 20, 22 are attached to the respective divided ends. In the state shown in FIG. 1, the clutch gears 20 and 22 are mutually connected by a coupling sleeve 24. That is, the coupling sleeve 24 has inner teeth formed on its inner peripheral surface so as to mesh with the clutch gears 20 and 24, and the inner teeth mesh with both the clutch gears 20 and 24. In this case, the divided right front axle can rotate integrally.

The coupling sleeve 24 is slidably supported by a support member (not shown) on the vehicle body side in the axial direction of the right front axle. The fork tip of the shift fork 26 is fitted in the fork groove of the coupling sleeve 24, and the base end of the shift fork 26 is connected to the output rod 30 of the vacuum actuator 28. The vacuum actuator 28 includes a diaphragm that partitions the inside of the housing into a negative pressure chamber 32 and an atmosphere chamber.
The output rod 30 is connected to this diaphragm.
Atmospheric pressure or negative pressure can be selectively supplied to the negative pressure chamber 32 by an electromagnetic switching valve (not shown), and a return spring 34 is accommodated in the negative pressure chamber 32. Negative pressure chamber 3
2 is supplied with air, the return spring 34 urges the output rod 30 in one direction via the diaphragm to bring the coupling sleeve 24 into the normal lock position, that is, the clutch gears 20 and 24 It is positioned at the position where it is connected to. On the other hand, when a negative pressure is supplied to the negative pressure chamber 32, the negative pressure pulls the diaphragm against the urging force of the return spring 34 and pushes the output rod 30 to the left as viewed in FIG. Accordingly, the coupling sleeve 24 is shifted from the lock position to the free position, and the clutch gear 2
As a result, the left front wheel FW is separated from the front wheel differential 18. The negative pressure chamber of the vacuum actuator 28 is supplied from the intake system of the engine 2 via the above-described electromagnetic switching valve. Transfer device: The transfer device 6 includes an input shaft 8 connected to the output shaft of the transmission 4 and an intermediate shaft 36 located coaxially with the input shaft 8. The input shaft 8 and the intermediate shaft 36 are rotatably supported on the transfer case side of the transfer device 6 independently of each other. Input shaft 8
A subtransmission mechanism 38 is disposed between the transmission and the intermediate shaft 36. Specifically, the auxiliary transmission mechanism 38 includes a pair of clutch gears 4.
0, 42, and these clutch gears 40, 42
Are attached to the ends of the input shaft 8 and the intermediate shaft 36 facing each other. The clutch gears 40 and 42 rotate integrally with the input shaft 8 and the intermediate shaft 36. Further, the intermediate shaft 36 rotatably supports the clutch gear 44, and the clutch gear 44 is provided with a low gear 46 coaxially and integrally. The low gear 46 meshes with the counter gear 48, and the counter gear 48 is
0 is attached to one end. Counter shaft 50
Are arranged in parallel with the input shaft 8 and the intermediate shaft 36, and are rotatably supported on the transfer case side. The other end of the counter shaft 50 is connected to the input shaft 8 via a pair of gears 52, 54. Therefore, the rotation of the input shaft 8 is transmitted to the low gear 46 via the pair of gears 52, 54, the counter shaft 50, and the counter gear 48.
The number of teeth of the gear 52 is smaller than the number of teeth of the gear 54,
The number of teeth of the low gear 46 is set to be larger than the number of teeth of the counter gear 48. That is, the counter shaft 50 rotates at a speed higher than the rotation of the input shaft 8, and the low gear 46 rotates at a lower speed than the rotation of the counter shaft 50.

Outside the clutch gears 40, 42, 44, a coupling sleeve 56 (first switching member) having the same structure as the above-described coupling sleeve 24 is disposed. 8 and slidably supported along the intermediate shaft 36. In the state shown in FIG. 1, the coupling sleeve 56 meshes with the clutch gears 40, 42, and the clutch gears 40, 4
2 are connected to each other (high gear position). In this case, the input shaft 8 is connected to the clutch gears 40, 4
2, the rotation of the input shaft 8 is directly transmitted to the intermediate shaft 36. On the other hand, when the coupling sleeve 56 is shifted from the high gear position to the clutch gear 44 side in FIG. 1, the coupling sleeve 56 is positioned at a position (low gear position) where the clutch gears 42 and 44 are connected to each other. That is, the coupling sleeve 56 at the low gear position is
0, 42 while the clutch gears 42, 44
And these clutch gears 42 and 44 are mutually connected. In this case, the rotation of the input shaft 8 is transmitted at a reduced speed from the counter shaft 50 side to the intermediate shaft 36 via the counter gear 48, the low gear 46, the clutch gear 44, the coupling sleeve 56, and the clutch gear 42.

A shift fork 58 is also engaged with the coupling sleeve 56, and the shift fork 58 can be reciprocated by an electric shift actuator 60. The shift actuator 60 will be described later. The intermediate shaft 36 is connected to the rear wheel output shaft 10 via a planetary gear type center differential device (center differential: differential mechanism) 62. For details, see Center differential 6
2 is a differential case composed of a ring gear (rear wheel side output element)
64, a sun gear 68 that meshes with the differential case 64 via a plurality of planetary gears 66, and a carrier (input element) 70 that rotatably supports the planetary gears 66.
The other end of the intermediate shaft 36 is coaxially connected to the carrier 70.
Extend coaxially. Sun gear 6 of center differential 62
8 is attached to one end of an inner sleeve shaft (front wheel side output element) 72, and the inner sleeve shaft 72 is rotatably supported on the intermediate shaft 36. Center differential 6
2 indicates that the rotation input from the intermediate shaft 36, that is, the driving force
Inner sleeve shaft 72 and rear wheel R
W can be transmitted to the differential case 64 which is an output member to the W. In this case, the gear ratio of the center differential 62 is
Drive power distribution is 30% on the front wheel FW side and 70% on the rear wheel RW side
It is set to be.

An inner sleeve shaft 72 of the center differential 62 extends toward the input shaft 8, and a clutch gear 74 is attached to the other end. Further, an outer sleeve shaft 76 is rotatably supported on the inner sleeve shaft 72,
The outer sleeve shaft 76 extends from the center differential 62 side toward the clutch gear 74 of the inner sleeve shaft 72.
A clutch gear 78 is attached to an end of the outer sleeve shaft 76 located on the clutch gear 74 side, and the clutch gear 74 of the inner sleeve shaft 72 is sandwiched between the intermediate shaft 36 and the clutch gear 78. The clutch gear 80 is mounted as described above.

On the outside of the clutch gears 74, 78, 80, a coupling sleeve 82 (first connecting means and second connecting means) is provided.
Coupling means) are arranged, and the coupling sleeve 8 is provided.
2 is supported slidably in the axial direction of the intermediate shaft 36. The coupling sleeve 82 has a circumferential groove on its inner peripheral surface, and its internal teeth are separated into two parts. When in the state shown in FIG. 1, the coupling sleeve 82 is engaged with the clutch gears 74 and 78,
4 and 78 are connected to each other (full-time 4WD position). At this time, the clutch gear 8
0 is located in the circumferential groove of the coupling sleeve 82, and the clutch gear 80 and the coupling sleeve 8
The mesh between the two has been released. The coupling sleeve 82 is moved from the full-time 4WD position to the clutch gear 8.
When the clutch gear 74 is shifted to the 0 side and is positioned at a position (2WD) where the clutch gears 74 and 80 are engaged, the clutch gears 74 and 80 are connected to each other while the clutch gear 7
Break the connection between 4,78. On the other hand, when the coupling sleeve 82 is shifted from the full-time 4WD position in the reverse direction and is positioned at a position where it engages with all of the clutch gears 74, 78, and 80 at the same time (directly-coupled 4WD position), they are interconnected. The coupling sleeve 82 is also engaged with a shift fork 84, and the shift fork 84 is reciprocated by a shift actuator 60 described later.

A front wheel F is attached to the outer sleeve shaft 76 described above.
The output sprocket 85 to the W side is attached,
A drive chain 86 is looped between the output sprocket 85 and the transfer sprocket 12 described above. Further, a hydraulic multi-plate clutch (clutch means) 88 is disposed between the outer sleeve shaft 76 and the differential case 64 of the center differential 62. The hydraulic multi-plate clutch 88 is an electromagnetically controlled valve body incorporating a hydraulic pump. 90 is hydraulically connected. The hydraulic multi-plate clutch 88 is connected to the outer sleeve shaft 76 and the differential case 64 in accordance with the hydraulic pressure supplied from the valve body 90, that is, the magnitude of the clutch pressure.
And the transmission of torque from the differential case 64 to the outer sleeve shaft 76 can be varied. Further, the valve body 90 is connected to the end of the above-described counter shaft 50, and supplies a hydraulic pressure from an oil pump 92 that generates a hydraulic pressure by rotation of the counter shaft 50 to the hydraulic multiple disc clutch 88. The details of the valve body 90 will be described later.

An electromagnetic switching valve and shift actuator 60 for the valve body 90 and the vacuum actuator 28 are provided by an electronic control unit (ECU) 9.
In response to the control signal from the control unit 4, the operation thereof is controlled. For this control, various sensors, switches, indicators, and the like are provided in the ECU 94 as shown in FIG. It is electrically connected. Specifically, the sensors include a front-rear G sensor 96 for detecting the front-rear acceleration (front-rear G) of the vehicle body, a throttle opening sensor 98 for detecting the opening of a throttle valve in the engine 2, and a steering wheel angle for detecting a steering wheel angle. There are a sensor 100, a vehicle speed sensor 102 for detecting a vehicle speed, and rotational speed sensors 104, 106, and 108.

The rotational speed sensor 104 detects the rotational speed of the front wheel FW from the rotational speed of the detection gear 110 attached to the right front axle near the right front wheel FW, and the rotational speed sensor 106 detects the rotational speed of the transfer sprocket 12 from the transfer sprocket The rotational speed sensor 108 detects the input rotational speed to the transfer device 6 from the rotational speed of the counter gear 48 of the subtransmission mechanism 38.

The switches connected to the ECU 94 include a brake switch 11 provided on a brake pedal.
2. There are a transfer (T / F) position switch 114 for detecting an operation state of the shift actuator 60, a drive mode changeover switch 115, and the like. The drive mode changeover switch 115 is a manual rotary switch disposed on an instrument panel in the vehicle compartment, and is a 2H position indicating 2WD, an AUTO position indicating auto mode, and a high direct connection 4W.
It has four switching positions, a 4HLc position indicating D and a 4LLc position indicating a row direct connection 4WD, and outputs a signal corresponding to the switching position to the EUC 94. Further, as shown in FIG. 1, a 4WD indicator 116 is incorporated in the instrument panel near the drive mode changeover switch 115, and the 4WD indicator 116 corresponds to the switching position selected by the drive mode changeover switch 115. The drive mode of the transfer device 6 thus set can be displayed. When the drive mode changeover switch 115 is set to AU
If the drive mode has been switched to the TO position, the drive mode selected by automatic switching at that time is displayed.

The transfer position switch 114 will be described later together with the shift actuator 60.
Further, the output torque information of the engine 2 is also supplied to the ECU 94, and this output torque information is
Is calculated based on the rotation speed, throttle opening, fuel supply amount, and the like of the engine. Vehicle speed sensor: Hereinafter, regarding the vehicle speed sensor 102 described above,
This will be described in detail with reference to FIG.

A sleeve yoke 118 at the end of the rear propeller shaft is connected to the rear wheel output shaft 10 of the transfer device 6, and this sleeve yoke 118 is spline-engaged with the rear wheel output shaft 10, while The housing of the transfer device 6 is supported via a slide bearing. Therefore, even if the rear axle moves forward and backward with the acceleration and deceleration of the vehicle, the forward and backward movement is absorbed by the sleeve yoke 118 sliding with respect to the rear wheel output shaft 10.

A ring member 120 is arranged concentrically outside the rear wheel side output shaft 10.
It is positioned on the side. The end of the ring member 120 on the side of the center differential 62 is fixed to the rear wheel output shaft 10 and rotates integrally with the rear wheel output shaft 10. An annular space is secured between the ring member 120 and the rear wheel output shaft 10, and this space can allow the sleeve yoke 118 to enter. Therefore, even if the sleeve yoke 118 slides toward the ring member 120 with respect to the rear wheel output shaft 10, the sleeve yoke 118 does not interfere with the ring member 120.

On the outer peripheral surface of the ring member 120, a screw gear 122 for driving the vehicle speed sensor 102 is formed.
The screw gear 122 of the vehicle speed sensor 102 is
4 are engaged. The vehicle speed sensor 102 is a screw gear 1
24 has a ring multi-pole magnet (not shown) attached coaxially thereto, and detects the rotation of the ring multi-pole magnet by a magnetoresistive element, and outputs a pulse signal proportional to the rotation speed of the rear wheel output shaft 10. Is output to the ECU 94.

According to the above-described vehicle speed sensor 102, since the driving screw gear 122 is formed on the ring member 120, the vehicle speed sensor 102 is located within the sliding range of the sleeve yoke 118 on the rear wheel output shaft 10. Can be arranged. As a result, it is possible to reduce the length of the rear wheel output shaft 10, that is, the entire length of the transfer device 6. Valve body: Next, the above-mentioned valve body 90 will be described in detail with reference to FIGS.

The valve body 90 has a built-in hydraulic pump 92, and the hydraulic pump 92 is an internal gear pump. As described above, the pump shaft of the hydraulic pump 92 is connected to the counter shaft 50 of the transfer device 6, and the rotation of the counter shaft 50 drives the hydraulic pump 92. Accordingly, the rotation direction of the hydraulic pump 92 is rotated forward or backward by the rotation direction of the counter shaft 50, that is, by the forward or backward movement of the vehicle. In the case of this embodiment, when the vehicle is moving forward, the hydraulic pump 92 is rotated forward, whereas when the vehicle is moving backward, the hydraulic pump 92 is rotated reversely.

As described above, since the rotational direction differs depending on whether the vehicle is moving forward or backward, the hydraulic pump 92 has a pair of inlet / outlet ports 126 and 128 whose discharge ports and suction ports are switched with each other depending on the rotational direction. Specifically, when the vehicle moves forward, one of the inlet / outlet ports 126 of the hydraulic pump 92 is used.
Is a discharge port, and the other inlet / outlet port 128 is a suction port.
6 is a suction port, and the inlet / outlet port 128 is a discharge port.

A pair of inlet / outlet ports 12 of the hydraulic pump 92
6, 128 are connected to a pump control valve 130, and the pump control valve 130 is composed of a spool valve at 5 ports and 3 positions. More specifically, the pump control valve 130 has a pair of inlet / outlet ports 132 and 134 spaced apart in the axial direction of the valve spool 131, and these inlet / outlet ports 1
It has a pair of supply ports 136 and 138 located on both sides of each of the inlet / outlet ports 132 and 134, and one outlet port 140 located in the center of the inlet / outlet ports 132 and 134. The pump 92 is connected to the inlet / outlet ports 126 and 128, respectively. The pair of supply ports 136 and 138 are connected to the pair of branch supply passages 14.
2 are connected to these branch supply passages 14.
2 is branched from one supply / discharge passage 144. The supply passage 144 is connected to a reservoir for the hydraulic fluid, and an oil filter 146 is interposed in the middle of the supply passage 144.

The valve spool 13 of the pump control valve 130
1 has three lands 148, 150 and 152, both ends of which are urged by a pair of return springs 153 and 155. When the hydraulic pump 92 is not driven, the valve spool 131 receives the urging force of the pair of return springs and is positioned at the neutral position as shown in FIG. In this neutral position, the land portion 1 of the valve spool 131 is
48, 150 and 152 are a pair of supply ports 136 and 13
8 and outlet port 140 are each closed, whereas a pair of inlet / outlet ports 132 and 134 are open. Annular chamber 15 between central land 148 and land 150
4 communicates with a spring chamber 158 on the right end side through an internal passage of the valve spool 131, and an annular chamber 156 between the land 148 and the land 152 also has a valve spool 1
31 is communicated with the spring chamber 160 on the left end side through an internal passage.

Now, when the hydraulic pump 92 is driven in the normal rotation direction, the hydraulic pump 92 has the inlet / outlet port 128 serving as a suction port and the inlet / outlet port 126 serving as a discharge port. The pressure fluid in the chamber 156 and the spring chamber 160 is sucked out, while the other annular chamber 154 and the spring chamber 158 receive the supply of the pressure fluid discharged from the hydraulic pump 92. Accordingly, a difference occurs in the pressure acting on both ends of the valve spool 131, and the valve spool 131 resists the urging force of the return spring 155, and
Is moved from the neutral position to the left first switching position as shown in FIG. In this first switching position, the lands 148, 152 of the valve spool 131 open the outlet port 140 and the supply port 136, respectively, while the land 150 keeps the supply port 138 closed. The input / output ports 132 and 134 are always kept open.
As described above, at the first switching position, the supply port 136 and the inlet / outlet port 128 communicate with each other via the annular chamber 154, and at the same time, the inlet / outlet port 132 and the outlet port 140 communicate with each other via the annular chamber 156. Can receive the supply of pressure fluid from the reservoir side via the pump control valve 130, and can continuously discharge the pressurized pressure fluid from the outlet port 140 of the pump control valve 130. The discharge amount of the hydraulic pump 92 is determined by its rotation speed, that is, the counter shaft 5 of the transfer device 6.
It increases as the rotation speed of 0 increases.

On the other hand, when the hydraulic pump 92 is rotated in the reverse direction, the valve spool 131 of the pump control valve 130 resists the urging force of the return spring 153, and moves rightward from the neutral position as shown in FIG. In the second switching position, the supply port 138 and the input / output port 132 communicate with each other, and the outlet port 140 and the input / output port 134 communicate with each other, as opposed to the case of the first switching position. The connection is established. Therefore, also in this case, the hydraulic pump 92 can receive the supply of the hydraulic fluid from the reservoir via the pump control valve 130 and continuously discharge the pressurized hydraulic fluid from the outlet port 140 of the pump control valve 130. it can.

Outlet port 14 of pump control valve 130
Numeral 0 is connected to a flow control valve 165 via a discharge passage 163, and the flow control valve 165 is a spool valve having three ports. The flow control valve 165 has a central inlet port 169 and an outlet port 171 and a return port 173 located on both sides of the inlet port 169 when viewed in the axial direction of the valve spool 167, and a discharge passage 163 is provided in the inlet port 169. It is connected. The return port 173 is connected to the supply passage 144 via the return passage 175.

The valve spool 167 of the flow control valve 165
Is a return spring 17 at one end, that is, at the left end in FIG.
7 and is moved rightward to the rest position to be positioned. When in the rest position, the valve spool 167
Are lands 162, 164 arranged so as to sandwich the outlet port 171 and the lands 16 sandwiching the inlet port 169 and closing the return port 173 between the lands 164.
6, and a land 179 located on the right side of the return port 173. The annular chamber between the lands 162 and 164, the annular chamber between the lands 164 and 166, and the lands 166 and 179
Are connected to each other through an internal passage of the valve spool 167, and the internal passage is connected to the valve spool 16.
7 are also open at both ends. The land 162 has a slightly smaller diameter than the other lands 164, 166, and 179, and has a smaller pressure receiving area.

The inlet port 169 of the flow control valve 165
Is supplied from the pump control valve 130 through the discharge passage 163 to the outlet port 171 through the internal passage of the valve spool 167 from the inlet port 169.
It is led to. Here, when the discharge amount from the hydraulic pump 92 increases, the outflow amount of the pressurized liquid from the outlet port 171 becomes larger than the inflow amount of the pressurized liquid into the inlet port 169.
7 is greatly narrowed by the internal passage, so that the inlet port 1
Since the pressure at the outlet port 171 is lower than the pressure at 69 and the pressure receiving area of the land 162 is smaller than the pressure receiving area of the land 164, the valve spool 167 returns from the rest position to the left as viewed in FIG. The spring 177 is moved against the urging force. As a result, the return port 173 is opened by the land 166 of the valve spool 167, and a part of the pressure fluid flowing into the inlet port 171 is released to the return port 173 through the internal passage of the valve spool 167.
The outflow amount of the pressure fluid from the outlet port 171 is adjusted.

The relief passage 168 is branched from the discharge passage 163, and the relief passage 168 is connected to the supply passage 144 on the downstream side of the oil filter 146. A relief valve 170 composed of a check valve is interposed in the relief passage 168. The relief valve 170 is opened when the pressure in the discharge passage 163 becomes equal to or higher than a predetermined relief pressure.

Outlet port 171 of flow control valve 165
Is connected to an electromagnetically actuated pressure control valve 174 via a metering passage 172. The pressure control valve 174 includes a spool valve 176 and an electromagnetic solenoid 178 for driving the spool valve 176. The spool valve 176 is located at the center as viewed in the axial direction of the valve spool 192, and is connected to the inlet port 1 to which the metering passage 172 is connected.
80, a pair of return ports 182, 184 located on both sides of the entrance port 180, an exit port 186 located between the return port 182 and the entrance port 180, and a gap between the entrance port 180 and the return port 184. It has five ports with an exit port 188 located. The pair of return ports 182 and 184 are connected to a return passage 189 via a branch passage, and the return passage 189 is connected to a reservoir side. One outlet port 186 is connected to a lubricating oil supply system in the transfer device 6, and the other outlet port 188 is connected to the above-described hydraulic multi-plate clutch 88 (see FIG. 1) through a pressure adjustment passage 190.

The valve spool 192 of the spool valve 176
4, has been moved leftward to the rest position under the biasing force of the return spring 193 at its right end. In this rest position, the left end of the valve spool 192 is the electromagnetic solenoid 1
78 are in contact with the rods 194. When in the rest position, the valve spool 192 has a land 196 that opens one outlet port 186 and a stepped land 198 that cooperates with the other outlet port 188, and the inlet port 180
Communicates with one outlet port 186 via an annular chamber 195 between the land 196 and the stepped land 198. The stepped land 198 includes a large-diameter land 197 located on the entrance port 180 side and a small-diameter land 199 located on the return spring 193 side.
97 cuts off the communication between the outlet port 188 and the annular chamber 195, while the small-diameter land portion 199 makes the outlet port 188 and the return port 184 communicate with each other. Therefore, when the valve spool 192 is in the rest position,
The hydraulic fluid in the hydraulic multi-plate clutch 88 is released toward the reservoir on the low pressure side, and the hydraulic multi-plate clutch 88 is in a released state.

The electromagnetic solenoid 178 is connected to the ECU 9 described above.
4 (see FIG. 2).
Is supplied with a control signal from the controller.
When the electromagnetic solenoid 178 is energized, its rod 19
4 is pushed out toward the valve spool 192, whereby the valve spool 192 is displaced rightward as viewed in FIG. 4 from the illustrated rest position against the biasing force of the return spring 193.
This displacement causes one exit port 186 to land
6, after which the other outlet port 188
The large-diameter land portion 197 of the stepped land 198
Between the outlet port 188 and the annular chamber 195,
The communication between the outlet port 188 and the inlet port 180 is established. The small-diameter land portion 199 of the stepped land 198 is in a state in which the connection between the outlet port 188 and the return port 184 is cut off simultaneously with the displacement of the valve spool 192. As a result, the pressure liquid supplied into the annular chamber 195 from the inlet port 180 of the pressure control valve 174 is discharged from the outlet port 188.
Is supplied to the hydraulic multi-plate clutch 88 through the pressure adjusting passage 190, and the pressure in the hydraulic multi-plate clutch 88, that is, the clutch pressure is raised.

When the clutch pressure of the hydraulic multi-plate clutch 88 reaches a predetermined pressure or higher, the valve spool 192 moves the electromagnetic solenoid 178 based on the pressure receiving area difference between the large-diameter land portion 197 and the small-diameter land portion 199 in the stepped land 198. The rod 194 is displaced toward the rest position while being pushed back.
This displacement causes the outlet port 188 to move the stepped land 19
After being closed by the large diameter land portion 197 of FIG. 8, the outlet port 186 is opened by the land 196. As a result, the clutch pressure in the hydraulic multi-plate clutch 88 is maintained,
By connecting the outlet port 186 from the inlet port 180 via the annular chamber 195, the pressure fluid is supplied to the outlet port 18.
6 to the lubricating oil supply system.

As described above, the clutch pressure which is built up in the hydraulic multi-plate clutch 88 is determined by the pressing force of the rod 194 of the electromagnetic solenoid 178 against the valve spool 192.
By controlling the amount of current supplied to the clutch 8, the clutch pressure of the hydraulic multiple disc clutch 88 can be controlled, and as a result, the torque transmission force of the hydraulic multiple disc clutch 88 can be arbitrarily varied.

The above-described hydraulic pump 92, pump control valve 130, flow control pulp 165, pressure control valve 17
4 and all of the passages are incorporated in the valve body 90, whereby the valve body 90 is downsized. Further, since the hydraulic pump 92 is driven by the counter shaft 50 of the transfer device 6, the rotational speed thereof is also increased as the vehicle speed increases, so that a small capacity hydraulic pump 92 can be used. This greatly contributes to downsizing of the valve body 90. Shift Actuator: Next, the above-described shift actuator 60 will be described in detail with reference to FIG.

The shift actuator 60 has a motor unit 202, and the motor unit 202 is mounted in a unit case (not shown).
Four. The electric motor 204 is electrically connected to the ECU 94, and receives a control signal from the ECU 94 to control the driving and the rotation direction. A pinion 206 is attached to an output shaft of the electric motor 204, and the pinion 206 is engaged with a drive rack 208.
The drive rack 208 extends in parallel with the axis of the transfer device 6 described above, and is slidably supported by the unit case.

The drive rack 208 is connected to the motor unit 20.
The main shift rail 210 (drive member) is connected to a protruding end of the unit shift case. That is, the main shift rail 210 is located coaxially with the drive rack 208 and extends integrally from the drive rack 208. In the vicinity of the main shift rail 210, a pair of sub-shift rails 212 and 214 are arranged in parallel with the main shift rail 210, and these sub-shift rails 212 and 214 are coaxially located at a predetermined interval. Being separated. The shift fork 58 described above is attached to one of the sub shift rails 212, and the shift fork 84 is attached to the other sub shift rail 214.

The main shift rail 210 and the pair of sub shift rails 212 and 214 are slidably supported by a plurality of rail receivers in the transfer case of the transfer device 6. These rail receivers are provided on the transfer case itself or on a fixed member in the transfer case, and more specifically, front and rear rail receivers 216 and 218 which are separated in the axial direction of the transfer device 6,
It comprises a center rail receiver 220 located between them. A support hole 222 is provided in the front rail receiver 216.
One end of one sub-shift rail 212 is slidably supported in the support hole 222.
A through hole 224 and a support hole 226 are formed in the center rail receiver 220 and the rear rail receiver 218 coaxially with the support hole 222, respectively, and the sub shift rail 212 (the second driven operation in claim 2) is formed in the through hole 224. The other end of the member is slidably supported. Also,
One end of the other sub-shift rail 214 (first driven operation member in claim 2) is slidably supported in the through hole 224, and the other end is slidably supported in the support hole 226 of the rear rail receiver 218. It is supported by. Further, another through hole 228 is formed in the center rail receiver 220 in parallel with the through hole 224.
Is formed with a through hole 230 in parallel with the support hole 226. One end of the main shift rail 210 extends through the inside of the through hole 228 of the center rail receiver 220 toward the front rail receiver 216, and is slidably supported by the through hole 228. The other end of the main shift rail 210 is slidably supported in the through hole 230 of the rear rail receiver 218, and is connected to the drive rack 208 in the through hole 230. That is, the tip of the drive rack 208 is also inserted into the through hole 230.

A pair of pinions 232, 234 are disposed on both sides of the center rail receiver 220, and these pinions 232, 234 are rotatably supported by bearings (not shown) provided on the center rail receiver 220. . One pinion 232 (the second driven operation member in claim 1 and the second pinion in claim 2) is positioned between the sub shift rail 212 and the main shift rail 210, and the other pinion 234 (claim). 1 is a first driven operation member and a first pinion in claim 1 are a sub shift rail 214 and a main shift rail 2.
10 and is located between them. Further, as is clear from FIG. 7, the pair of pinions 232 and 234 have a part of their teeth missing, and have tooth missing portions on the outer periphery.

The sub shift rail 212 has a rack 23
6 (a driven rack) is formed.
36 always meshes with the pinion 232. Further, a rack portion 238 (a driven rack portion) is also formed on the sub-shift rail 214, and this rack portion 238 also always meshes with the pinion 234. On the other hand, a pair of racks 240 and 242 (drive racks) cooperating with the pinions 232 and 234 are formed on the main shift rail 210 so as to be separated from each other in the axial direction of the main shift rail 210. The racks 240, 242
May consist of a single rack portion having rack teeth formed between them.

In the state shown in FIG. 7, the rack portion 240 of the main shift rail 210 is not engaged with the pinion 232, and is located on the right side of the pinion 232 in FIG. At this time, the missing tooth portion of the pinion 232 is positioned on the main shift rail 210, and the teeth defining both ends of the missing tooth portion are respectively located on the main shift rail 21.
It is in contact with 0. That is, the main shift rail 2
In FIG. 10, a portion connected to the left side of the rack portion 240 is formed as a flat stopper surface 241, and the stopper surface 241 is formed at a position suitable for contacting the teeth defining both ends of the toothless portion of the pinion 232. ing. Therefore, the rotation of the pinion 232 is prevented by the stopper surface 241 of the main shift rail 210 (second rotation).
Stopper means).

On the other hand, the rack portion 242 of the main shift rail 210 is meshed with the pinion 234 at the right end thereof. Have been. Further, a portion connected to the right side of the rack portion 242 also has a stopper surface 24 similar to the stopper surface 241 described above.
3 (first stopper means).

In the above-described shift actuator 60, since the pair of sub-shift rails 212 and 214 are supported by the common through hole 224 of the center rail receiver 220, the support structure is simple. Transfer position sensor: The above-described transfer position switch 114 includes four switches 244,
246, 248, and 250, and these switches are arranged in the center rail receiver 220. Specifically, a pair of mounting holes are formed in the center rail receiver 220 on the main shift rail 210 side,
These mounting holes are separated from each other in the axial direction of the main shift rail 210, and the inner ends thereof face the through holes 228. Switches 244 and 246 are mounted in the respective mounting holes, and these switches 244 and 246 have balls 252 at the inner ends of the mounting holes. On the other hand, two holes 254a and 254b cooperating with the balls 252 of the switches 244 and 246 are formed in the main shift rail 210, and these holes 254 also have predetermined intervals in the axial direction of the main shift rail 210. And separated. In the state of FIG. 7, the switch 244 has its ball 252
a, and is in a state of being lifted by the main shift rail 210, and the switch 244 outputs an off signal to E.
Output to CU94. On the other hand, the switch 246 causes the ball 252 to fall into the hole 254b,
Output to U94.

The remaining switches 248 and 250 have the same configuration as the switches 244 and 246 described above.
These switches 248 and 250 are connected to the sub shift rail 21.
2, 214 side, and a center rail receiver 2
It is attached to a member integral with 20. That is, FIG.
In the state of (2), the switch 248 outputs the OFF signal to the ECU 94 when the ball 252 comes out of the hole 254 of the sub-shift rail 214.
In 50, the ball 252 falls into the hole 254 of the sub shift rail 212, and outputs an ON signal to the ECU 94.

Since the switches 244 to 250 are all mounted on the center rail receiver 220, the center rail receiver 220 can be configured as a switch unit. Driving mode of transfer device: Next, the driving mode of the transfer device 6 will be described below for each driving mode. Full-time 4WD: When in the state of FIG. 7, the shift fork 58 of the sub-shift rail 212
Of the coupling fork 8 of the sub-shift rail 214 is positioned at the high position.
4 positions the coupling sleeve 82 of the transfer device 6 at the full-time 4WD position. Therefore, FIG.
The coupling sleeve 56 interconnects the clutch gears 40 and 42, as shown in FIG. 2, and the input shaft 8 of the transfer device 6 is directly connected to the intermediate shaft 36. On the other hand, the coupling sleeve 82 connects the clutch gears 74 and 78 to each other, whereby the inner sleeve shaft 72 and the outer sleeve shaft 76 are integrally rotated.

Accordingly, in this case, the driving force of the intermediate shaft 36 is transmitted from the center differential 62 to the rear wheel output shaft 10 via the differential case 64, and the rear propeller shaft and the rear wheel differential 14 are transmitted from the rear wheel output shaft 10. Are transmitted to the left and right rear wheels RW through the rear wheel, thereby rotating these rear wheels RW. On the other hand, since the driving force of the intermediate shaft 36 is also transmitted from the center differential 62 to the inner sleeve shaft 72, the driving force is also transmitted from the inner sleeve shaft 72 to the output sprocket 85 via the outer sleeve shaft 76. Sprocket 85 is also rotated. As a result, the rotational force of the output sprocket 85 is transmitted to the front propeller shaft 16 via the drive chain 86 and the transfer sprocket 12, and transmitted from the front propeller shaft 16 to the left and right front wheels FW via the front wheel differential 18. , These front wheels FW are also rotated, and the vehicle runs with four-wheel drive. At this time, as is apparent from FIG. 8, the ECU 94 has positioned the sleeve 24 at the lock position via the vacuum actuator 28, and the left and right front axles are connected to each other via the front wheel differential 18. The center differential 62 sets the driving force distribution to the front wheels FW and the rear wheels RW, that is, the front-rear driving force distribution to 3: 7. Even if the vehicle moves, in this case, the driving force of the rear wheel RW is large, and the vehicle can be started well. Further, when the vehicle is accelerating during turning, the steering characteristic is neutral steer, and the turning performance of the vehicle is also improved.

As described above, the ECU 94 can control the clutch pressure of the hydraulic multiple disc clutch 88.
If the clutch pressure in the hydraulic multiple disc clutch 88 is raised and the hydraulic multiple disc clutch 88 is engaged, the differential of the center differential 62 can be limited. Further, since the ECU 94 can arbitrarily change the clutch pressure of the hydraulic multi-plate clutch 88, that is, the torque transmitting force, the ECU 94 arbitrarily controls the distribution of the driving force between the front and rear wheels in a range from 3: 7 to 5: 5. Thus, the differential of the center differential 62 can be limited in accordance with the running state of the vehicle, and an optimal driving force distribution can be selected. An example of the differential limiting control of the center differential 62 is disclosed in, for example, JP-A-62-261538 and JP-A-62-279137. High direct connection 4WD: the shift actuator 60 is in the state of FIG.
Is rotated in one direction (counterclockwise as viewed in FIG. 7) in response to a command signal from the ECU 94, the main shift rail 210 is slid leftward in FIG. 7 via the pinion 206 and the drive rack 208, The shift actuator 60 is shown in FIG.
Transition to the state shown in. That is, the main shift rail 2
Due to the sliding of 10, one of the rack portions 240 reaches the position immediately before the pinion 232, and the other rack portion 242 rotates the pinion 234 clockwise as shown in FIG. The rotation of the pinion 234 at this time causes the sub shift rail 214 to slide in the opposite direction to the main shift rail 210, and as a result,
The shift fork 84 directly connects the coupling sleeve 82 of the transfer device 6 from the full-time 4WD position.
Shift to position. The rotation of the pinion 234 is stopped when the missing tooth portion faces the stopper surface 243 of the main shift rail 210. At this time, the pinion 2
Since the rotation of the sub-shift rail 32 is prevented by the stopper surface 241 of the main shift rail 210, the sub-shift rail 212 does not slide.

With the sliding of the main shift rail 210 and the sub shift rail 214 described above, the switch 246 causes the ball 252 to fall out of the hole 254b of the main shift rail 210 as shown in FIG. Then, the switch 248 causes the ball 252 to fall into the hole 254 of the sub shift rail 214, and outputs an ON signal to the ECU 94. In this case, EC
U94 stops the rotation of the electric motor 204 when the output of the switch 248 switches from off to on.

When the coupling sleeve 82 of the transfer device 6 is at the direct connection 4WD position, as shown in FIG.
In addition to 78, the clutch gear 80 of the intermediate shaft 36 is also interconnected. Therefore, the intermediate shaft 36 and the inner sleeve 7
2 is directly connected, the center differential 62 is locked, and the intermediate shaft 36 is directly connected to the outer sleeve shaft 76, so that the drive system on the front wheel FW side and the drive system on the rear wheel RW side are mechanically connected. Then, a driving force (about 5: 5) equal to the shared load is transmitted to the front and rear wheels. Low direct connection 4WD: the shift actuator 60 is in the state of FIG.
Is further rotated in one direction (counterclockwise as viewed in FIG. 7), the main shift rail 210 is further slid to the left as shown in FIG. Therefore, the rack portion 240 of the main shift rail 210 moves while engaging with the pinion 232, and the pinion 232 is rotated clockwise. With this rotation, the sub shift rail 212 slides on the opposite side to the main shift rail 210, and as a result, the shift fork 58 of the sub shift rail 212 moves the coupling sleeve 56 of the sub transmission mechanism 38 from the high gear position to the low gear position. Shift to position. At this time, pinion 2
34 is not engaged with the rack portion 242 of the main shift rail 210, and its rotation is prevented by the stopper surface 243 of the main shift rail 210, so that the sub shift rail 214 does not slide. . As a result, the shift fork 84 of the sub shift rail 214 holds the coupling sleeve 82 of the transfer device 6 at the directly connected 4WD position.

With the sliding of the main shift rail 210 and the sub shift rail 212 described above, the switch 246 moves the ball 252 into the hole 2 of the main shift rail 210.
The switch 250 outputs an ON signal to the ECU 94, and the switch 250 switches the ball 252 out of the hole 254 of the sub-shift rail 212 and outputs an OFF signal to the ECU 94.
Output to 94. The ECU 94 stops the rotation of the electric motor 204 when the output from the switch 246 switches from off to on.

In this case, since the coupling sleeve 56 connects the clutch gears 42 and 44 of the subtransmission mechanism 38 to each other as is apparent from FIG. The rotation is transmitted to the intermediate shaft 36 via the clutch gears 46 and the clutch gears 44 and 42, and the rotation speed of the intermediate shaft 36 is reduced. In addition,
The transmission of the driving force from the intermediate shaft 36 to the rear wheel RW side and the front wheel FW side is the same as in the case of the above-described high direct connection 4WD.

The coupling sleeve 56 of the subtransmission mechanism 38 is shifted when the vehicle is stopped. 2WD: When the shift actuator 60 is in the state shown in FIG. 7 and the electric motor 204 of the motor unit 202 is rotated in the reverse direction (clockwise in FIG. 7), the main shift rail 210 is evident from FIG. Slide to the right. In this case, the pinion 234 is rotated counterclockwise by meshing with the rack portion 242 of the main shift rail 210, and this rotation causes the sub shift rail 214 to slide in a direction opposite to the main shift rail 210. Accordingly, the shift fork 84 of the sub shift rail 214 moves the coupling sleeve 82 of the transfer device 6 from the full-time 4WD position to the position (2WD) where the clutch gear 80 of the intermediate shaft 36 and the clutch gear 74 of the inner sleeve shaft 72 are interconnected. Position). in this case,
The pinion 232 does not engage with the rack portion 240 of the main shift rail 210, and
The rotation is stopped by the zero stopper surface 214. Accordingly, the sub shift rail 212 does not slide, and the shift fork 5 of the sub shift rail 212 does not slide.
8 holds the coupling sleeve 56 of the subtransmission mechanism 38 at the high gear position.

The sliding of the main shift rail 210 and the sub shift rail 214 causes the switch 244 to move the ball 252 into the hole 25 of the main shift rail 210.
4a, the switch 246 outputs an ON signal to the ECU 94, and the switch 246 causes the ball 252 to exit the hole 254b of the main shift rail 210, and outputs an OFF signal to the ECU 94.
Output to CU94. The ECU 94 stops the rotation of the electric motor 204 when the output from the switch 244 switches from off to on.

In this case, the coupling sleeve 82 of the transfer device 6 connects the clutch gear 80 of the intermediate shaft 36 and the clutch gear 74 of the inner sleeve shaft 72 to each other as is apparent from FIG.
Is in a locked state, and when the engagement of the hydraulic multi-plate clutch 88 is released, the driving force of the intermediate shaft 36 is
, And the driving force of the intermediate shaft 36 is not transmitted to the front wheel output sprocket 85. Therefore, only two rear wheels RW are driven.

At this time, the ECU 94 drives the vacuum actuator 32 to slide the sleeve 24 to the free position. Therefore, the front axle clutch gears 20, 2
The connection between the two has been disconnected, whereby the rotation of the front propeller shaft 16 has been stopped. When the rotation of the front propeller shaft 16 is stopped in this way, not only is the fuel economy excellent, but noise associated with the rotation can be eliminated.

When the vehicle is running at 2WD (that is, the coupling sleeve 24 is
And the coupling sleeve 82
Are connected to the clutch gear 80 and the clutch gear 74 while the clutch gear 78 is disconnected from the clutch gear 74, and the front propeller shaft 16
If the switch 94 is unexpectedly switched to the 4WD drive mode, the ECU 94 first engages the hydraulic multi-plate clutch 88 to release the outer sleeve shaft 76.
To rotate. As a result, the front propeller shaft 16 rotates, and this rotation rotates the differential case of the front wheel differential 18, thereby switching the clutch gear 20 of the front axle to the forward rotation (the front propeller shaft 16 is in a stopped state). During forward running, the clutch gear 20 is rotating in the reverse direction, and by rotating the front propeller shaft 16, the rotational direction of the clutch gear 20 is reversed.) Then, the above-described rotational speed sensor 104 EC based on the output signal from
U94 controls the hydraulic pressure of the hydraulic multi-plate clutch 88 to substantially synchronize the rotations of the clutch gears 20, 22.
Next, the ECU 94 sets the vacuum actuator 28
Moves the coupling sleeve 24 to connect the clutch gears 20 and 22. As a result, the four-wheel drive state is established, and thereafter, the required drive force to the front wheel FW is controlled by adjusting the engagement force of the hydraulic multi-plate clutch 88, so that the four-wheel drive traveling required transiently is possible. Becomes At this time, when the hydraulic multi-plate clutch 88 is completely connected, a state equivalent to a directly connected 4WD state in which the front and rear wheels are directly connected is obtained.

In the direct connection 4WD equivalent state, when the temporary four-wheel drive request disappears, the ECU 94
Firstly issues a signal to the vacuum actuator 28 for disconnecting the coupling sleeve 24, thereby generating a command signal for releasing the connection of the hydraulic multi-plate clutch 88 when the disconnection of the clutch gears 20, 22 is completed. I do. As a result, the front propeller shaft 16
Is stopped again, and returns to the steady two-wheel drive running state.

As described above, when the four-wheel drive traveling is suddenly requested during the two-wheel drive traveling, the hydraulic multi-plate clutch 88 is controlled and the operation for coupling the coupling sleeve 24 is simply performed. The transition to four-wheel drive travel will be achieved. On the other hand, when switching from the two-wheel drive traveling to the steady full-time four-wheel drive traveling, the coupling of the clutch gears 20 and 22 by the coupling sleeve 24 is performed in the same manner as in the unexpected four-wheel drive traveling request described above. After the operation, the ECU 94 sets the rotation speed sensor 10
6, 108, the rotation between the front wheel FW side and the rear wheel RW side, that is, the rotation of the clutch gear 74 of the inner sleeve shaft 72 and the rotation of the clutch gear 78 of the outer sleeve shaft 76 are substantially synchronized. Therefore, the connection state of the hydraulic multi-plate clutch 88 is controlled. When the coupled center differential 62 is close to the locked state, the ECU 94 drives the shift actuator 60 while maintaining the clutch pressure, and moves the coupling sleeve 82 of the transfer device 6 from the 2WD position to the clutch gear 78 side. Slide it. When the tooth tips of the clutch gears 74 and 78 coincide with each other, the internal teeth 82 of the coupling sleeve 82
a starts to engage with the clutch gear 78, and after the clutch gears 74, 78, 80 have been temporarily connected to each other, the coupling sleeve 82
Further slide to the 8 side to connect only the clutch gears 74 and 78. Thus, the shift to the full-time 4WD position is completed. Note that, in this embodiment, when the hydraulic multi-plate clutch 88 is connected, a complete rotation is avoided to allow a slight rotation difference between the clutch gear 74 and the clutch gear 78, and the clutch is completely connected directly. , That is, the shift of the teeth between the clutch gear 74 and the clutch gear 78 and the advance of the coupling sleeve 82 to the clutch gear 78 are prevented.

After the shift to the full-time 4WD position is completed, the clutch pressure of the hydraulic multiple-plate clutch 88 is released. By controlling the clutch pressure of the clutch 88, optimal torque distribution control according to the running state can be performed. By releasing the connection by the coupling sleeve 24 as described above,
When switching from the two-wheel drive state in which the rotation of the front propeller shaft 16 is stopped to the full-time four-wheel drive state, first, the clutch means (hydraulic multi-plate clutch 88) is connected to rotate the clutch gears 20 and 22 mutually. , The coupling sleeve 24 slides smoothly, and then the coupling state of the hydraulic multi-plate clutch 88 is adapted to the synchronization of the clutch gears 74, 78, 80, so that the coupling sleeve 82 is smoothly moved. , And the switching from 2WD to 4WD can be easily performed.

In order to switch from the full-time 4WD running state to the direct connection 4WD, the ECU 94 first sets the hydraulic multi-plate clutch 88 based on the output signals of the rotation speed sensors 106 and 108 to rotate the clutch gears 74 and 80 substantially synchronously. To combine. When a state close to the synchronous rotation is achieved, the ECU 94 drives the shift actuator 60 while maintaining the clutch pressure of the hydraulic multi-plate clutch 88, and moves the coupling sleeve 82 to the full-time 4WD.
From the position to the clutch gear 78 side, in a state where the coupling sleeve 82 and the clutch gear 80 are connected by the internal teeth 82b of the coupling sleeve 82, that is, in a state where the clutch gears 74, 78 and 80 are mutually connected. Shift to the direct connection 4WD position. Thereafter, the clutch pressure of the hydraulic multi-plate clutch 88 is released.

By coupling the hydraulic multi-plate clutch 88 and synchronizing the clutch gears 74 and 80 substantially as described above, the coupling sleeve 82 can be smoothly slid, and the direct connection 4WD can be performed from the full-time 4WD position.
Switching to the position can be easily performed. In addition, the clutch gears 74, 78,
80 is directly connected to the hydraulic multiple disc clutch 8.
8, the driving force equal to the shared load of the front and rear wheels can be reliably transmitted to the front and rear wheels, and energy consumption for generating hydraulic pressure required for clutch engagement is eliminated, thereby reducing energy loss. be able to.

To switch from the running state of the direct connection 4WD to the full time 4WD, the ECU 94 drives the shift actuator 60 without operating the hydraulic multi-plate clutch 88, and connects the coupling sleeve 82 to the direct connection 4WD.
From the position to the clutch gear 80 side, and the connection between the internal teeth 82b of the coupling sleeve 82 and the clutch gear 80 is released, that is, the full-time 4WD in a state where only the clutch gears 74 and 78 are connected to each other. Shift to position. Thereafter, the ECU 94 sets the hydraulic multi-plate clutch 8
By controlling the clutch pressure of No. 8, optimal torque distribution according to the running state can be performed.

Before driving the shift actuator 60, the hydraulic multi-plate clutch 88 is connected so as to maintain the synchronous rotation between the clutch gears 74 and 80, and the coupling sleeve is connected with the hydraulic multi-plate clutch 88 connected. 82
May be shifted to the full time 4WD position. In this case, after the shift to the full-time 4WD position is completed, the clutch pressure of the hydraulic multi-plate clutch 88 is released. Thereafter, the ECU 94 controls the clutch pressure of the hydraulic multi-plate clutch 88 according to the running state.

Further, from the running state of full-time 4WD, 2
To switch to WD, the ECU 94 first engages the hydraulic multi-plate clutch 88 and sets the clutch gears 74, 78, 8
0 rotation substantially synchronized, and the hydraulic multi-disc clutch 8
8 while the clutch pressure of the clutch gear 8 is maintained.
0, slide the inner teeth 82 of the cup link sleeve 82
The clutch gears 74, 78, 80 are respectively connected by a. Further, when the coupling sleeve 82 is slid toward the clutch gear 80, the coupling sleeve 82
Is a 2WD in a state where the connection with the clutch gear 78 is released.
Shift to position. Then, the ECU 94 starts driving the vacuum actuator 28 to release the coupling of the clutch gears 20 and 22 by the coupling sleeve 24. Thereafter, the clutch pressure of the hydraulic multi-plate clutch 88 is released. Here, the connection between the clutch gears 20 and 22 by the coupling sleeve 24 is released first. Conversely, when the clutch pressure is released first, the clutch gear 2
This is because a rotational force in the opposite direction is applied to 0, which makes it difficult to slide the coupling sleeve 24 thereafter.

As described above, by coupling the hydraulic multi-plate clutch 88 and substantially synchronizing the rotations of the clutch gears 74, 78, 80, the coupling sleeve 82 can be smoothly slid, and the full-time 4WD can be used. 2
Switching to WD can be easily performed. Shift actuator drive mode detection: As is apparent from the above description, the ECU 94 determines the transfer position switch 114 of the shift actuator 60, that is, the four switches 244, 2 as shown in Table 1 below.
The drive mode can be detected by the combination of the outputs from 46, 248, and 250.

[0075]

[Table 1]

In this embodiment, the transfer position switch 114 has four switches 246 to 250 for detecting four drive mode positions.
Transfer position switch 1
14 can identify four drive mode positions by a combination of outputs from the remaining switches even if one of the switches is omitted.

When the shift actuator 60 switches the drive modes, the reciprocating ranges of the main shift rail 210 corresponding to the respective driving modes are continuous with each other. Or some of them may overlap. Auto mode traveling: When the drive mode changeover switch 115 of the instrument panel is operated to the AUTO position, the ECU 94 controls the operation of the shift actuator 60 according to the traveling state of the vehicle, and the drive mode of the transfer device 6 Can be automatically switched as follows based on full-time 4WD, for example. (1) When the ignition key switch of the base engine 2 is turned on, the ECU 94 moves the shift actuator 60 to the position shown in FIG.
And the drive mode is set to full time 4WD. (2) Full-time 4WD → 2WD When all of the following conditions are satisfied, the drive mode is switched from full-time 4WD to 2WD.

A) When the vehicle is running at low to medium speeds, b) The road surface is flat and the road is good, such as asphalt. C) The steering wheel operation is moderate. (3) 2WD → Full-time 4WD When at least one of the following conditions is satisfied, the drive mode is switched from 2WD to full-time 4WD.

A) When the vehicle is running at high speed, b) When the road surface is a sloping road,
Any of sandy areas, bad roads or snowy roads, c) Steering operation is sudden,
d) Large wheel slip. (4) Full-time 4WD → High direct connection 4WD When the vehicle is traveling at low speed and at least one of the following conditions is satisfied, the drive mode is full-time 4WD.
Is switched to high direct connection 4WD.

A) The road surface is steep or extremely bad, and b) Wheel slip is large continuously. (5) High direct connection 4WD → full time 4WD When the vehicle shifts to middle-high speed driving, the drive mode is switched from high direct connection 4WD to full time 4WD. Manual mode: The drive mode switch 115
When being operated from the AUTO position to any one of the 4HLc position, the 4LLc position, and the 2H position, the ECU 94 controls the operation of the shift actuator 60, and switches the drive mode between high direct connection 4WD and low direct connection according to the position of the changeover switch 115. 4WD
Or, switch to 2WD.

As described above, since the drive mode of the transfer device 6 can be switched only by operating the drive mode switch 115, the drive mode can be easily switched. In addition, if the drive mode is operated to the AUTO position, almost all driving states can be covered, so that the vehicle can be easily driven. The changeover switch 11
The 4H position (full time 4WD) may be provided at the 5 switching position.

The present invention is not limited to the first embodiment described above, and various modifications are possible. For example, a transfer device as shown in FIG. 15 can be used as the second embodiment. This transfer device is different from that of the first embodiment in that a hydraulic multi-plate clutch 88 is arranged between the carrier 70 of the center differential 62 as an input element and the outer sleeve shaft 76. In this case, the operation and effects of the transfer device of the second embodiment are basically the same as those of the first embodiment. In the first embodiment, the clutch gears 74, 78,
One coupling sleeve 8
2, the coupling sleeve 82 is divided into two coupling sleeves 82c and 82d as shown, and these coupling sleeves 82c and 82d are slid independently by a shift actuator. It is also possible. In this case, in the shift actuator 60, the sub shift rail is added.

In the second embodiment, when the coupling of the coupling sleeves 82c and 82d is not established due to the failure of the shift actuator 60 or the like, the hydraulic multi-plate clutch 88 is connected and the driving of the vacuum actuator 28 is stopped. By coupling the front axles, the driving force from the input element, that is, the carrier 7070 is directly transmitted to the outer sleeve shaft 76 as the front wheel side output member, and the front wheels are driven by this driving force, Avoidance operations in an emergency are also possible.

In the first and second embodiments described above,
Although the example in which the center differential 62 makes the driving force distribution different between the front wheel FW side and the rear wheel RW side has been described, the invention is not limited to such a configuration, and the driving force distribution is set to be equal. A bevel gear type differential device may be used. In this case, the torque distribution control in the full-time 4WD state cannot be performed, but in the full-time 4WD state, the differential between the front and rear wheels can be limited by controlling the clutch pressure of the hydraulic multiple disc clutch 88. . In addition, as in the first and second embodiments, a synchronizing operation can be performed when the drive mode is switched, and the drive mode can be easily switched.

Further, as a third embodiment, for example, a transfer device as shown in FIG. 16 can be used. The center differential (differential mechanism) 62 of the transfer device also has a different driving force distribution between the front wheel FW side and the rear wheel RW side. The gear ratio is set. Then, a hydraulic multi-plate clutch (clutch means) 88
Is a differential case (rear wheel side output element) 6 of the center differential 62
4 and an inner sleeve shaft (front wheel side output element) 72. A coupling sleeve 8 capable of connecting a clutch gear 74 of an inner sleeve shaft 72 and a clutch gear 78 of an outer sleeve shaft (wheel-side member) 76.
2c, and a coupling sleeve 82d (second connecting means) capable of connecting the clutch gear 74 of the inner sleeve shaft 72 and the clutch gear 80 of the intermediate shaft 36 are provided.

Then, the coupling sleeves 82c, 82
2d is independently slidable by the shift actuator 60 as in the case of the second embodiment. First, when the vehicle is traveling at 2WD, the clutch gears 74 and 80 are connected to each other by the coupling sleeve 82d, and the connection between the clutch gears 74 and 78 by the coupling sleeve 82c is not made. Further, the vacuum actuator 28 is driven, and the clutch gears 20 and 2 of the front axle are driven by the coupling sleeve 24.
No connection is made between the two. Therefore, the center differential 62
The rear wheel RW is securely locked by mechanically locking the
To the front propeller shaft 1 by disconnecting the connection between the clutch gears 20 and 22 and the connection between the clutch gears 74 and 78.
The rotation of 6 is stopped, not only in terms of fuel economy,
Noise caused by the rotation can be eliminated.

To switch from 2WD to full-time 4WD, the ECU 94 first drives the shift actuator 60 while the vehicle is stopped, and slides the coupling sleeve 82c of the transfer device 6 toward the clutch gear 78 so that the clutch gear 78 moves. 74, 78 are interconnected. The connection between the clutch gears 74 and 78 causes the stopped front propeller shaft 16 to rotate, and this rotation rotates the differential case of the front wheel differential 18 to switch the clutch gear 20 of the front axle to forward rotation. . Next, the ECU 94 stops the driving of the vacuum actuator 28 to slide the coupling sleeve 24 to connect the clutch gears 20 and 22 together. Thereafter, the ECU 94 couples the hydraulic multi-plate clutch 88 so as to maintain the synchronous rotation of the clutch gears 74 and 80, and further drives the shift actuator 60 while maintaining the clutch pressure of the hydraulic multi-plate clutch 88. The coupling sleeve 82d is slid toward the clutch gear 78 to release the connection between the clutches Gifu 74, 78. Thus, the shift to the full-time 4WD position is completed. Then, after the shift to the full-time 4WD position is completed, the clutch pressure of the hydraulic multiple disc clutch 88 is released. Thereafter, during traveling in full-time 4WD, the ECU 94 controls the clutch pressure of the hydraulic multi-plate clutch 88 in accordance with the traveling state, thereby performing optimal torque distribution control in accordance with the traveling state.

As described above, by coupling the hydraulic multi-plate clutch 88 so as to maintain the synchronous rotation between the clutch gears 74 and 78, the coupling sleeve 82d can be smoothly slid, and the full-time operation can be performed from 2WD. Switching to 4WD can be easily performed. If a synchronizing device such as a synchronizing mechanism is provided between the clutch gears 74 and 78, a smooth connection can be made even during the traveling.
To switch from full-time 4WD to direct-coupled 4WD, the ECU 94 first engages the hydraulic multi-plate clutch 88 based on the outputs of the rotational speed sensors 106 and 108 to rotate the clutch gears 74 and 78 substantially synchronously. When a state close to synchronous rotation is achieved, the ECU 94
Drives the shift actuator 60 while maintaining the clutch pressure of the hydraulic multiple disc clutch 88, and further slides the coupling sleeve 82d toward the clutch gear 78 side.
When the tooth tips of the clutch gears 74 and 80 coincide with each other, the coupling sleeve 82d starts to mesh with the clutch gear 80, and the clutch gears 74 and 80 are connected to each other, that is, the coupling sleeves 82c and 82d.
As a result, the clutch gears 74, 78, 80 are shifted to the directly connected 4WD position in a state where they are connected to each other. Thereafter, the clutch pressure of the hydraulic multi-plate clutch 88 is released.

As described above, by coupling the hydraulic multi-plate clutch 88 and substantially synchronizing the clutch gears 74 and 80, the coupling sleeve 82d can be slid smoothly, and the full-time 4WD can be changed to the direct connection 4WD. Can be easily switched. Further, by mechanically connecting the clutch gears 74 and 80 directly by the coupling sleeve 82d, a driving force equal to the shared load of the front and rear wheels can be reliably applied to the front and rear wheels without connecting the hydraulic multi-plate clutch 88. It is possible to reduce the energy loss without consuming the energy for generating the hydraulic pressure required for the clutch engagement of the hydraulic multi-plate clutch 88.

To switch from the direct connection 4WD to the full time 4WD, the ECU 94 needs to
0WD and directly connect the coupling sleeve 82d to 4WD.
From the clutch gear 80 to the clutch gear 7 side.
The connection between 4,80 is released, and full-time 4WD is achieved. Then, after the shift to the full-time 4WD position is completed, the ECU 94 controls the clutch pressure of the hydraulic multi-plate clutch 88 according to the traveling state during the full-time 4WD traveling, so that the optimal torque distribution according to the traveling state is performed. It can be performed.

Before driving the shift actuator 60, the hydraulic multi-plate clutch 88 is connected so as to maintain the rotational synchronization between the clutch gears 74 and 80, and the coupling sleeve 82d is connected with the hydraulic multi-plate clutch 88 connected.
May be shifted to the full time 4WD position. In this case, after the shift to the full-time 4WD position is completed, the clutch pressure of the hydraulic multi-plate clutch 88 is released, and thereafter, the ECU 94 controls the clutch pressure of the hydraulic multi-plate clutch 88 according to the running state. .

To switch from full-time 4WD to 2WD, the ECU 94 first requires the hydraulic multiple disc clutch 88
The shift actuator 60 is driven to slide the coupling sleeve 82d toward the clutch gear 80 in a state where the rotations of the clutch gears 74 and 80 are substantially synchronized and the clutch pressure of the hydraulic multi-plate clutch 88 is maintained. And the clutch gears 74 and 80 are mutually connected. And EC
U94 releases the clutch pressure of the hydraulic multi-plate clutch 88, starts driving the vacuum actuator 28, and sets the clutch gear 2 by the coupling sleeve 24.
0,22 are disconnected. Thereafter, the ECU 94
Further drives the shift actuator 60 to slide the coupling sleeve 82c toward the clutch gear 80, thereby releasing the connection between the clutch gears 74 and 78 to achieve 2WD.

As described above, by coupling the hydraulic multi-plate clutch 88 and substantially synchronizing the rotations of the clutch gears 74 and 80, the coupling sleeve 82d can be slid smoothly, and the full-time 4WD to 2WD can be used.
Switching to is easily performed. Also, by connecting the clutch gears 74 and 80 with the coupling sleeve 82d, the hydraulic multi-plate clutch 88 does not need to be connected.
The center differential 62 can be in the locked state, and energy is not consumed for generating the hydraulic pressure required for the clutch engagement of the hydraulic multiple disc clutch 88, so that the energy loss can be reduced.

If the coupling by the coupling sleeve 82d is not performed due to a failure of the shift actuator 60 or the like, the center differential 62 can be brought into a state close to the locked state by connecting the hydraulic multi-plate clutch 88. In the case of 2WD, the driving force can be reliably transmitted to the rear wheel side.
The WD state can be set.

In the third embodiment, the hydraulic multi-plate clutch 88 is arranged between the inner sleeve shaft 72 and the differential case 64 of the center differential 62.
4 and the carrier (input element) 70 of the center differential 62, or between the inner sleeve shaft 72 and the carrier 70 of the center differential 62. Needless to say, in the transfer devices of the second and third embodiments, the coupling of the clutch gears 74, 78, and 80 by the coupling sleeves 82c and 82d may be performed by one coupling sleeve.

In the first, second and third embodiments, the coupling sleeves 82c and 82d are connected to the intermediate shaft 36.
Although the connection between the inner shaft 72 and the inner sleeve shaft 72 is made, the connection between the intermediate shaft 36 and the differential case 64 or the connection between the inner sleeve shaft 72 and the differential case 64 may be made.
Preferably, by connecting the intermediate shaft 36 and the inner sleeve shaft 72, the transfer device can be made compact.

The first and second embodiments described above correspond to claims 2 to 4, and the third embodiment has a structure corresponding to claims 1 and 4.

[0098]

As described above, according to the transfer apparatus for a four-wheel drive vehicle of the first aspect, in a vehicle capable of switching between two-wheel drive travel and four-wheel drive travel, the controllability for the switching is improved. An excellent transfer device can be obtained. Then, the driving force can be reliably transmitted to the driving wheels by inhibiting the differential of the differential mechanism by the function of the clutch means during the two-wheel drive traveling without the connection by the connecting means.

Also in the transfer device for a four-wheel drive vehicle according to the second aspect, in a vehicle capable of switching between two-wheel drive traveling and four-wheel drive traveling, a transfer device excellent in controllability of the switching can be obtained. . According to the transfer device for a four-wheel drive vehicle according to the third aspect, at the time of four-wheel drive in which the vehicle can travel while permitting rotational differential between the front and rear wheels, the clutch device is appropriately operated to drive the front and rear wheels. The power distribution can be varied, and the optimum driving force distribution can be set according to the running state.

According to the transfer device for a four-wheel drive vehicle of the fourth aspect, since the differential mechanism can be mechanically locked by the second connecting means, it is not necessary to connect the clutch means. Energy consumption can be suppressed without consuming the energy required for the operation.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vehicle including a 4WD transfer device.

FIG. 2 is a block diagram showing a control system of the transfer device of FIG.

FIG. 3 is a diagram showing a mounting position and a configuration of a vehicle speed sensor.

FIG. 4 is a hydraulic circuit diagram in a valve body that supplies a hydraulic fluid to a hydraulic multi-plate clutch.

FIG. 5 is a diagram showing a first switching position of a valve spool in the pump control valve.

FIG. 6 is a view showing a second switching position of the valve spool of FIG. 5;

FIG. 7 is a longitudinal sectional view of a shift actuator based on full-time 4WD.

FIG. 8 is a schematic diagram showing the transfer device at the time of full-time 4WD.

FIG. 9 is a vertical sectional view of the shift actuator switched to the high direct connection 4WD.

FIG. 10 is a schematic diagram showing a transfer device in a high direct connection 4WD.

FIG. 11 is a longitudinal sectional view of the shift actuator switched to the low direct connection 4WD.

FIG. 12 is a schematic diagram showing a transfer device in a row direct connection 4WD.

FIG. 13 is a longitudinal sectional view of the shift actuator switched to 2WD.

FIG. 14 is a schematic diagram showing a transfer device in 2WD.

FIG. 15 is a schematic view showing a part of a transfer device according to a modification.

FIG. 16 is a schematic view showing a part of a transfer device according to another modification.

[Explanation of symbols]

6 Transfer device 20 Clutch gear 22 Clutch gear 24 Coupling sleeve 28 Vacuum actuator 60 Shift actuator 62 Center differential (differential mechanism) 64 Differential case (Rear wheel output element) 70 Carrier (Input element) 72 Inner sleeve shaft (Front wheel output element) 82) Coupling sleeve (first and second connecting means) 82c Cup link sleeve (first connecting means) 82d Coupling sleeve (second connecting means) 88 Hydraulic multi-plate clutch (clutch means) 94 ECU

Continuation of front page (72) Inventor Yuichi Goda 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation

Claims (4)

[Claims] An input element receives power from a power generation device, transmits the power to the front wheel side and rear wheel side output elements at different distribution ratios, and generates a differential between the front wheel side and rear wheel side output elements. And a first coupling means for intermittently connecting between one of the front wheel side and rear wheel side output elements and a wheel side member that transmits power toward the corresponding wheel, A clutch provided between two of the front-wheel-side output element, the rear-wheel-side output element, and the input element, and controlling rotational differential between the two elements. Transfer device for a four-wheel drive vehicle. 2. A difference that receives power from a power generating device at an input element, transmits power to a front wheel side and rear wheel side output element, respectively, and allows a differential between the front wheel side and rear wheel side output elements. A driving mechanism, a first connecting means for intermittently connecting any one of the front wheel side and rear wheel side output elements and a wheel side member that transmits power toward its corresponding wheel, A transfer device for a four-wheel drive vehicle, comprising: clutch means for intermittently connecting the other of the rear wheel side output elements or the input element and the wheel side member. 3. The transfer device for a four-wheel drive vehicle according to claim 2, wherein said differential mechanism transmits power to said front wheel side and rear wheel side output elements at different distribution ratios. 4. The apparatus according to claim 1, further comprising: a second connection unit that connects two of the input element, the front wheel output element, and the rear wheel output element in an intermittent manner. 4. The transfer device for a four-wheel drive vehicle according to claim 1.