JPH0620829B2 - Vehicle power transmission device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power transmission device for driving front wheels and rear wheels of a vehicle with the same engine.

[Conventional technology]

2. Description of the Related Art Conventionally, for example, in front wheel drive base (FF base) vehicles, various types have been developed in which drive connection of rear wheels can be achieved by coupling hydraulically operated clutches.

Then, in order to operate the clutch, an oil pump is provided separately (as an oil pump, an electric oil pump or an oil pump for an automatic transmission is used), and the discharge pressure of the oil pump is appropriately adjusted to the clutch. The power is supplied to control the transmission of the driving force to the rear wheels.

[Problems to be solved by the invention]

However, in such a conventional power transmission device for a vehicle, the oil pump must be provided separately, and the means for adjusting the discharge pressure of the oil pump becomes complicated.

The present invention is intended to solve such problems, and provides a power transmission device for a vehicle, which has a compact structure and can automatically adjust the discharge pressure from an oil pump with a simple structure. The purpose is to do.

[Means for solving problems]

For this reason, the vehicle power transmission device of the present invention includes the first rotary shaft that transmits the driving force from the engine coupled to the transmission to the front wheels of the vehicle and the second rotary shaft that transmits the driving force to the rear wheels. Driven by the difference in rotational speed of the oil pump to discharge a discharge pressure corresponding to the same rotational speed, the oil pump being interposed between the first rotary shaft and the second rotary shaft and being discharged by the oil pump. A clutch mechanism for joining the two rotating shafts, a hydraulic circuit for supplying a discharge pressure from the oil pump to the clutch mechanism, and a hydraulic control means provided in the hydraulic circuit for controlling the discharge pressure to adjust the joining force of the clutch mechanism. It is a summary of having equipped.

[Action]

With the above configuration, when a rotation speed difference occurs between the first rotating shaft and the second rotating shaft, a discharge pressure corresponding to the rotation speed difference is discharged from the oil pump. It is supplied to the clutch mechanism, and the clutch mechanism operates to connect the first rotating shaft and the second rotating shaft.

Further, the hydraulic pressure supplied to the clutch mechanism is controlled by the hydraulic control means, and the coupling ratio between the first rotary shaft and the second rotary shaft is controlled accordingly. This controls the distribution of power to the front wheel side and the rear wheel side. Further, the oil pump and the clutch mechanism are arranged adjacent to each other, and the entire device is compactly constructed.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 6 show a vehicle power transmission device as one embodiment of the present invention, in which front wheels and rear wheels are driven by the same engine. The present invention relates to a power transmission device for a part-time four-wheel drive vehicle. As shown in FIG. 1, a transversely mounted engine 1 having a clamp shaft extending in the vehicle width direction is arranged.
A transmission 2 that constitutes a power transmission system T is connected to a drive gear (or a fourth-speed counter gear) 4 fixed to an output shaft 3 that extends in the vehicle width direction of the transmission 2. Is a gear 9 which is integral with the sheath shafts 8 and 8'constituting the first rotation shaft.
Are in mesh.

The sheath shafts 8 and 8'are connected by bolts 11, and a shaft 13 for driving front wheels (hereinafter referred to as "front wheel output shaft 13") is spline-fitted to the shafts 8 and 8'with gears 9. The front wheel output shaft 13 and the sheath shafts 8 and 8'constitute the first rotating shaft. In this way, the power from the power transmission system T is always transmitted to the first rotary shaft.

Also, the power transmission device 15 transmits the driving force to the sheath shafts 8 and 8 ′ forming the first rotation shaft and the rear wheels 17 and 18.
It is interposed between a rear-wheel drive shaft 19 (hereinafter referred to as “rear-wheel output shaft 19”) that constitutes a rotary shaft.

A gear 21 is attached to the front wheel output shaft 13, and the gear 21 meshes with a ring gear 25 of a front wheel differential mechanism 23 (hereinafter referred to as “front wheel differential 23”). As a result, the torque from the front wheel output shaft 13 is applied to the front wheel differential 23.
Is transmitted to the left and right front wheel drive shafts 27 and 29,
The front wheels 5 and 6 are rotationally driven.

Further, the rear wheel output shaft 19 is connected to a propeller shaft 33 via a bevel gear mechanism 31, and a bevel gear 35a at the rear portion of the propeller shaft 33 has a rear wheel differential mechanism 37 (hereinafter,
It is in mesh with a ring gear 39 of "the rear wheel diff 37"). As a result, the torque from the rear wheel output shaft 19 is divided by the rear wheel diff 37 and transmitted to the left and right rear wheel drive shafts 43, 45, and the rear wheels 17, 18 are rotationally driven.

The power transmission device 15 is driven by a rotational speed difference between the sheath shafts 8 and 8'and by extension the front wheel output shaft 13 and the rear wheel output shaft 19, and is a gear type oil that discharges oil at a pressure corresponding to the rotational speed difference. A clutch for suppressing the rotational speed difference by adjusting the degree of coupling between the front wheel output shaft 13 side and the rear wheel output shaft 19 side by receiving the pump 50 and the oil discharged from the oil pump 50 via the hydraulic circuit 51. A hydraulic control means 55 is provided in the hydraulic circuit 51.
Is installed.

Next, the structure and arrangement of the oil pump 50 and the clutch mechanism 53 will be described.

As shown in FIG. 2, the oil pump 50 and the clutch mechanism 53 are integrally provided in the transmission case 52 in which the transmission 2 is provided. A pump case 57 is spline-fitted to the sheath shaft 8 ′, a clutch mechanism 53 is provided on the outer diameter side of the pump case 57, and an oil pump 50 is provided on the inner diameter side of the pump case 57. It is provided.

As the oil pump 50, for example, a crescent-free internal gear pump (rotor pump) is used, and the oil pump 50 includes an inner gear 59 as an external gear (pinion) spline-fitted to the rear wheel output shaft 19. The inner gear 59 has an outer gear 61 which meshes with the inner gear 59 but is arranged eccentrically with the inner gear 59. The outer gear 61 serves as an internal gear.
9 and the outer gear 61 are formed so that the tooth profile thereof forms a hypocycloid curve, and the pump case 57,
58.

The pump case 58 is fixed to the pump case 5 with bolts 63.
The pump main body is formed of the pump cases 57 and 58.

As shown in FIG. 2, an annular step portion 58a is formed on the outer circumference of the pump case 58, and an annular piston 65 that constitutes the clutch mechanism 53 is fitted into the step portion 58a. As a result, this piston 65 and cylinder 67
The oil chamber 71 is formed between the pump case 58 and the sleeve 69, and the clutch mechanism 5
Reference numeral 3 denotes a plurality (here, 4) of annular clutch plates 73 that are spline-engaged with the outer peripheral portions of the pump cases 57 and 58 that are clutch hubs, and a sleeve 69 that is a clutch cylinder 67 that is engaged with the rear wheel output shaft 19. A plurality of pressing plates 75 that are spline-engaged with the inner peripheral portion are provided, and the clutch plates 73 and the pressing plates 75 are alternately arranged to form a frictional engagement element. Further, in the oil chamber 71 of the clutch mechanism 53, an annular spring 77 as an urging means is interposed between the inner wall 67a of the cylinder 67 and the piston 65, and the piston 65 is preliminarily contacted with the pressure plate 75 in the contact direction. Urging force (initial limiting torque) is applied.

Incidentally, 79 is a filter provided at an oil suction port 81 formed at the end of the rear wheel output shaft 19.

Reference numeral 83 is a stopper member for the clutch plate 73 and press plate 75, and 85 is a stopper member for the cylinder 67.

The hydraulic circuit 51 will be described below.

The hydraulic circuit 51 is a first hydraulic circuit 5 that connects the inside of the transmission case 52, which is an oil sump, with the oil pump 50.
4, a second hydraulic circuit 56 that connects the oil pump 50 and the clutch mechanism 53 to each other.

As shown in FIG. 3, the oil pump 50 is formed with two ports 101 and 103. One of the ports 101 is an oil passage 105 which is a first oil passage and a check valve which is a first intake check valve. Valve 107 and suction oil passage 1
Is connected to an oil suction port 81 opened at the shaft end of the rear wheel output shaft 19 via a hydraulic pressure control valve 09, and is discharged through an oil passage 111 which is a third oil passage and a check valve 113 which is a first discharge check valve. The other port 103 is connected to the oil passage 115 so that the other port 103 is the second oil passage.
6, Check valve 10 which is the second intake check valve
8 and a suction oil passage 109, which are in communication with the oil suction port 81, and which are an oil passage 112 which is a fourth oil passage and a check valve 114 which is a second discharge check valve.
Is connected to the discharge oil passage 116 via the.

Further, the suction oil passage 109 and the oil chamber 7 of the clutch mechanism 53
1, a spring 121 is provided between the oil passage 119 and the oil passage 119.
An oil passage 125 with a relief valve 123 whose opening pressure is set by the above is interposed.

By the oil passages 105, 106 and 109, the first hydraulic circuit 5
4 to form the oil passages 111, 112, 115, 116.
This forms a second hydraulic circuit 56. Also, the oil chamber 7
1 to the atmosphere open oil passage 1 with an orifice 127 which is a throttle means formed in the piston 65 of the clutch mechanism 53.
29 is branched.

The oil passage 129 is provided so as to face the clutch plate 73 and the compression plate 75, and oil is discharged from the oil passage 129 toward the clutch plate 73 and the compression plate 75.

The relief valve 123 and the orifice 127 constitute a hydraulic control unit 55.

Reference numeral 131 denotes a plug for holding the relief valve 123 in the pump case 58 as shown in FIG.
It is screwed to 8.

The ports 101 and 103 and the oil passages 105 and 10 described above
6,109,111,112,115,116,11
9, relief valve 123, check valve 107, 1
08, 113 and 114 are formed inside the pump case 58.

The vehicle power transmission device as one embodiment of the present invention is configured as described above, and its operation will be described below.

When a difference in rotational speed occurs between the front wheel output shaft 13 side and the rear wheel output shaft 19 side, and the inner gear 59 rotates in the direction of arrow a, the oil is absorbed by the oil suction port 81, the oil passage 109, the check valve 108, and the oil. After being sucked into the port 103 via the passage 106, it is discharged from the oil passage 115 via the port 101, the oil passage 111, and the check valve 113. The discharge pressure characteristic at this time is as indicated by reference character A in FIG.

On the contrary, when the inner gear 59 rotates in the direction of the arrow b, oil is sucked into the port 101 through the oil suction port 81, the oil passage 109, the check valve 107 and the oil passage 105, and then the port 103, the oil passage 112, Check valve 11
And then discharged from the oil passage 116. The discharge pressure characteristic at this time is also as shown by the symbol A in FIG.

In the characteristic A, when the rotational speed difference exceeds a certain value, the discharge pressure hardly rises because the relief valve 123 opens when the discharge pressure is above each predetermined value.

Further, the characteristic portion of the characteristic A before the relief valve 123 is opened is proportional to the square of the rotational speed difference due to the action of the orifice 127.

Here, the opening characteristics of the relief valve 123 and the orifice 1
Since the aperture degree of 27 is set appropriately, the characteristic A can be set to a desired value.

When the hydraulic pressure having the discharge characteristic set appropriately in this way is supplied to the oil chamber 71 and the piston 65 is pushed out, the clutch plate 73 and the pressure plate 75 are brought into close contact with each other, and the pump case 57 and The sleeve 69, that is, the front wheel output shaft 13 side and the rear wheel output shaft 19 side engage.
At this time, since the discharge pressure characteristic of the oil pump 50 is set, the force that pushes out the piston 65 changes according to the characteristic, so that the degree of engagement of the clutch mechanism 53, that is, the degree of torque transmission also changes accordingly.

By the way, the front wheel output shaft 13 is, as shown in FIG.
A gear 21 is attached, and this gear 21 meshes with a ring gear 25 of a front wheel differential mechanism 23 (hereinafter referred to as "front wheel differential 23"). As a result, the front wheel output shaft 1
The torque from 3 is split by the front wheel diff 23 and transmitted to the left and right front wheel shafts 27 and 29 to rotationally drive the front wheels 5 and 6.

Further, the rear wheel output shaft 19 is connected to a propeller shaft 33 via a bevel gear mechanism 31, and the bevel gear 35 of the propeller shaft 33 has a rear wheel differential mechanism 37 (hereinafter referred to as "rear wheel diff 37"). Of the ring gear 39.
As a result, the torque from the rear wheel output shaft 19 is split by the rear wheel diff 37 and transmitted to the left and right rear wheel shafts 43, 45,
The rear wheels 17, 18 are rotationally driven.

Therefore, in normal straight running, the front wheels 5, 6 and the rear wheels 1
Since the effective radii of the tires 7 and 18 are the same and the slip rotation speeds of the tires are low, there is no difference in rotation speed between the front wheel output shaft 13 side and the rear wheel output shaft 19 side, so the oil pressure from the oil pump 50 is reduced. Therefore, the clutch mechanism 53 is not operated and the driving force is not transmitted to the rear wheels 17 and 18. Therefore, the front two wheels are driven only by the front wheels 5 and 6.

Here, when the rotation speed on the front wheel output shaft 13 side becomes faster than the rotation speed on the rear wheel output shaft 19 side during traveling with front wheel drive, for example, when traveling on a snowy road, during sudden acceleration, or during braking. If the rear wheels are locked, the inner gear 5
9 rotates in the direction of arrow a.

At this time, as described above, the circulation and the oil accumulated in the mesh case 52 are discharged from the oil suction port 8
1, oil passage 109, check valve 108, oil passage 106, and port 101, oil passage 1
11. The oil is discharged from the oil passage 115 into the oil chamber 71 through the check valve 113. Since this discharge pressure is a value corresponding to the difference in rotational speed between the front wheel output shaft 13 side and the rear wheel output shaft 19 side, the force with which the piston 65 presses the pressing plate 75 and the clutch plate 73 is also the above rotational speed difference. Depends on.

As a result, the magnitude of the torque transmitted by the clutch mechanism 53 also changes according to the rotational speed difference. When the rotational speed difference occurs in this way, the clutch mechanism 53 is brought into contact with the coupling degree according to the difference, so that the rotational speed difference is suppressed, and as a result, the rear wheel output shaft 19 side. Torque is also transmitted to. When the front wheels 5 and 6 are idling by this, it is automatically switched to the four-wheel drive state and the rear wheels 17 and 18 are
To rotate.

If the rotational speed difference exceeds a certain value, for the sake of safety, the relief valve 123 acts to suppress the rise of the discharge pressure and suppress the torque transmission to the rear wheel output shaft 19 side to a constant value. .

On the contrary, when the rear wheels 17 and 18 rotate faster than the front wheels 5 and 6, for example, when the front wheels 17 and 18 are in a braking state and become slightly locked, the inner gear 59 automatically rotates in the direction of arrow b.

At this time, the oil supply path automatically switches,
Oil is sucked from the port 101 through the oil suction port 81, the oil passage 109, the check valve 107, and the oil passage 105, and the port 103, the oil passage 112, and the check valve 114.
And is discharged from the oil passage 116 into the oil chamber 71.

Since this discharge pressure also has a value corresponding to the rotational speed difference between the front wheel output shaft 13 side and the rear wheel output shaft 19 side, the force with which the piston 65 presses the pressure plate 75 and the clutch plate 73 is equal to the rotational speed difference. Depends on.

As a result, the magnitude of the torque transmitted by the clutch mechanism 53 also changes according to the rotational speed difference. In this case as well, the clutch mechanism 53 is brought into contact with the coupling degree according to the rotational speed difference, so that the rotational speed difference is suppressed,
As a result, torque is also transmitted to the front wheel output shaft 13 side. As a result, the four wheels are automatically driven and the rear wheels 17, 18
The front wheels 5 and 6 are rotationally driven by suppressing the rotation of.

Also in this case, when the rotational speed difference exceeds a certain value, for the sake of safety, the relief valve 123 prevents the discharge pressure from increasing and the torque transmission to the front wheel output shaft 13 side is constant. It is suppressed to the value.

[Effect of Example]

As described above, the clutch mechanism 53 automatically controls the amount of torque transmission to the rear wheel output shaft 19 side in accordance with the difference in rotational speed between the front wheel output shaft 13 side and the rear wheel output shaft 19 side, and the four-wheel drive state. Therefore, when the rotational speeds of the front wheels 5, 6 are much higher than the rotational speeds of the rear wheels 17, 18, the front wheels 5, 5
As the rotational speed of 6 decreases and the rotational speeds of the rear wheels 17 and 18 increase, the rotational speed difference is reduced. In the slip state of the front wheels 5 and 6, the slip of the front wheels 5 and 6 is reduced. The driving torque to the rear wheels 17 and 18 is increased to prevent inability to travel. Also, when the rear wheels 17, 18 at the time of braking tend to be locked, the rear wheels 17,
The drive torque to 18 is increased to prevent the rear wheels 17, 18 from locking.

On the other hand, when braking, the front wheels 5 and 6 are slightly rocked
When the rotational speeds of the rear wheels 17, 18 are much higher than the rotational speed of the front wheel 6, the braking torque applied to the front wheels 5, 6 is increased to prevent the front wheels 5, 6 from locking.

Further, during normal turning, the rotational speeds of the front wheels 5 and 6 are slightly higher than the rotational speeds of the rear wheels 17 and 18, the brake torque acts on the front wheels 5 and 6, and the drive torque is 4 times on the rear wheels 17 and 18. A turning drive is performed in a wheel drive state.
In such a case, by controlling the relief valve 123 so that the discharge pressure of the oil pump 50 does not exceed a certain value, the four-wheel drive and the two-wheel drive are automatically switched, and the braking torque during turning is increased. Prevent automatically.

Further, depending on the degree of throttle of the orifice 127 and the opening characteristic of the relief valve 123 that constitute the hydraulic control means 55,
By arbitrarily setting the rising characteristics and the limiting characteristics shown in Fig. 6, torque transmission suitable for the running state can be set,
This has the effect of enabling stable driving.

Further, since the piston 65 is constantly urged to the compression plate 75 by the annular spring 77 and there is no clearance between the clutch plate 73 and the compression plate 75, a difference in rotation occurs and the oil pump 50 operates. When the discharge is started, the pressing plate 75 immediately presses the clutch plate 73, and after the differential rotation speed is generated, the hydraulic pressure rises quickly and the clutch torque corresponding to the differential rotation speed is instantaneously generated. can get.

Then, by the annular spring 77, the symbol C in FIG.
A large initial limiting torque B can be applied as compared with a conventional one not provided with a biasing mechanism, and the value of the initial limiting torque B can be set to an arbitrary value by the annular spring 77.

In particular, the rising portion of the characteristic A shown in FIG. 6 is proportional to the square of the rotational speed difference, so that a small rotational speed difference
There is also the advantage that the torque does not change so much and the reduction in braking during low-speed turning can be reduced.

Further, since the clutch mechanism 53 of the type in which the piston plate 75 and the clutch plate 73 are pressed by the piston 65 and the rotor pump having a small radius without a crescent are used as the oil pump 50, the structure can be made compact and Since the oil pump 50 is arranged on the inner diameter side of the clutch mechanism 53 so that the oil pump 50 is accommodated within the width of the clutch mechanism 53 in the axial direction, the size of the clutch mechanism 53 can be reduced.

That is, the oil pump 50 and the clutch mechanism 53 are
Since it is arranged coaxially with the rotary shafts 13 and 19 and is aligned with the rotary shafts 13 and 19 in the radial direction, the size in the radial direction can be reduced.

Further, in this device, the product of the transmission torque and the rotational speed difference causes heat loss due to energy loss, but a part of the oil is directed toward the pressure plate 73 and the clutch plate 75 of the clutch mechanism 53 through the oil passage 129. Since it is discharged, there is an advantage that the pressure plate 73 and the clutch plate 75 of the clutch mechanism 53 can be sufficiently cooled and lubricated.

Further, in this apparatus, what is used as the oil pump 50 is a rotor pump having a small radius without a crescent as shown in FIG. 3, and among the trochoid pumps, a gerotor pump and a trochocentric pump (internal with crescent) Compared with a tooth gear), the meshing portion 50a, the tooth tip portion 50b, and the port portion 50c have the following features.

I) At the meshing part 50c 1. Since the enclosed volume is very small, there is little leakage,
The pulsation is also small.

2. The radial angle of the outer rotor is small because the pressure angle α shown in Fig. 3 is small. Therefore, the bearing load of the outer rotor is reduced and the torque loss is reduced.

3. Since the amount of slip is small, wear on the meshing surface is low and friction loss is low.

In the part where the slip speed becomes faster, the meshing of the teeth is disengaged.

II) In the tooth tip seal portion 50b, with 2 to 3 teeth, the IN port 101 (103) and OUT
The port 101 (103) is sealed. In addition, the clearance at the tooth tip becomes smaller when the pressure becomes higher. Therefore, high volumetric efficiency is obtained.

III) In the IN and OUT port parts 50c, there are no tooth meshing parts, and the gear chambers are continuously connected. Therefore, the suction part is easily filled with oil, and the occurrence of cavitation is small. In addition, since the teeth are not in contact with each other, there is no noise or tooth wear.

In addition, it has excellent characteristics compared to the Troco Centric pump (internal gear pump with crescent). 1) Since there is no cricent, it contributes to ease of body processing and cost reduction.

2) The difference in the number of teeth between the pinion 59 and the internal gear 61 is small (for example, 1), the outer diameter of the internal gear 61 is reduced, and the mounting size and torque loss are reduced.

3) The tooth profile is made based on the hypocycloid curve, which can reduce slippage and improve quietness of teeth.

4) There is a large amount of discharge per rotary shaft, and a small mounting size is sufficient to obtain the same amount of discharge.

5) The meshing ratio is close to 1, and if one tooth meshes, the meshing of the other teeth will end, so this is effective in reducing the meshing noise and the tooth surface wear.

[Other Examples]

Next, a modified example of the hydraulic control means 55 in the first embodiment is shown in FIG. 7 as a second embodiment.

In FIG. 7, the relief valve device 200 provided in place of the relief valve 123 constituting the hydraulic control means 55 is different, and therefore, other oil pumps 50 and hydraulic circuits 51 are provided.
Is the same as that already described. In the relief valve device 200, a piston 203 is provided at the other end of a spring 121, one end of which is in contact with the relief valve 123, and a control hydraulic pressure for controlling the opening pressure of the relief valve 123 is duty-controlled on the piston 203. Structure. And for the purpose of duty control
The constant hydraulic pressure supplied via the solenoid valve 2
Although controlled by 07, this solenoid valve 207 receives a signal from the engine speed sensor 211 input to the computer 209, a signal from the front wheel output shaft speed sensor 213,
A signal from the rear wheel output shaft rotation speed sensor 215, a signal from the throttle opening sensor 217, and a brake operation sensor 21.
The hydraulic pressure acting on the piston 203 is controlled by a signal from the steering angle sensor 221 and a signal from the steering angle sensor 221.

As the hydraulic pressure of a constant pressure supplied through the orifice 205, the control hydraulic pressure may be used when the transmission 2 is an automatic transmission, and in the case of a manual type, an oil pump is installed. However, the oil pressure can be secured by using the oil pressure of the power steering, the oil pressure for the brake booster, the oil pressure obtained from the discharge port side of the oil pump 50, or the like.

According to the above structure, as the engine 1 becomes heavier, this is detected by the throttle opening signal to detect the oil pump 50.
If the discharge pressure is controlled so as to be increased, it is possible to increase the amount of driving force transmitted to the rear wheels 17 and 18 in the four-wheel drive state to allow the vehicle to travel.

The front wheels 5 and 6 and the rear wheels 17 and 18 are locked by controlling the discharge pressure of the oil pump 50 to be large when the foot brake operation state is detected by the brake operation detection switch and turned on. It is possible to shorten the braking distance and obtain a stable braking state.

Further, by detecting the steering angle and controlling the discharge pressure to become lower as the steering angle increases, it becomes possible to avoid the tight corner braking phenomenon and smoothly turn.

Further, the discharge pressure of the oil pump 50 can be adjusted and controlled according to the number of revolutions of the engine and the speed of the vehicle by each detection signal input to the computer, so that a stable traveling state can be achieved.

Next, a modified example of the hydraulic control means 55 in the first embodiment is shown in FIG. 8 as a third embodiment.

FIG. 8 shows the orifice 12 which constitutes the hydraulic control means 55.
7 shows an orifice device 231 provided instead of 7.
The other oil pump 50 and hydraulic circuit 51 are the same as those already described.

The orifice device 231 is disposed in the atmosphere opening oil passage 129, and one chamber 236 of the casing 235 partitioned by the diaphragm 233 into two chambers has a communication hole 237 communicating with the atmosphere opening oil passage 129 and the atmosphere. Has an air hole 239 communicating with the. Furthermore, the communication hole 23
7 is opened and closed by a needle valve 238 attached to the diaphragm 235. Further, the casing 233
The other chamber 240 in the inside is provided with a manifold negative pressure transmission port 241 that communicates with the intake manifold portion of the engine 1 and transmits the manifold negative pressure.
42 is interposed.

When this orifice device 231 is used, the negative pressure of the manifold decreases as the load of the engine increases, and the diameter of the orifice, that is, the passage area of the communication hole 237 decreases, but the communication hole 237 is completely closed. Keep it open to some extent. When the engine load increases as described above, the driving force also increases.
By reducing 37, the oil pressure of the oil pump 50 immediately rises to the four-wheel drive state.

Further, as the engine load decreases, the manifold negative pressure increases, and the diameter of the orifice, that is, the communication hole 237.
Of the front wheel output shaft 13 and the rear wheel output shaft 19 to increase the slip amount between the front wheel output shaft 13 and the rear wheel output shaft 19 to increase the amount of slippage between the front wheels 5, 6 and the rear wheels 17, 18. It is possible to avoid the tight corner braking phenomenon at the time of turning by increasing the allowance of the rotational speed difference and to smoothly turn.

Next, a fourth embodiment having different hydraulic control means will be described with reference to FIG.

FIG. 9 shows the orifice 12 which constitutes the hydraulic control means 55.
7 shows an orifice device 251 provided in place of No. 7, and the other oil pump 50 and hydraulic circuit 51 are the same as those already described.

In the orifice device 251, a casing 253 disposed in the atmosphere opening oil passage 129 is provided with a transmission port 255 for transmitting the oil pump discharge hydraulic pressure of the power steering of the steering wheel and a transmission port 257 for transmitting the manifold negative pressure, A piston 261 is housed between the manifold negative pressure transmission port 257 and the oil pump discharge pressure transmission port 255 in the casing 253 through a spring 259 so as to be vertically movable by the discharge hydraulic pressure of the oil pump of the power steering and the negative pressure of the manifold. Further, at the lower end of the piston 261, a needle valve 263 for opening and closing the atmosphere opening oil passage 129 is provided to control the opening to the atmosphere side 265. When the orifice device 251 having this structure is used, the oil pressure of the power steering becomes higher as the steering angle becomes larger, so that the needle valve 263 retracts to greatly open the atmosphere opening oil passage 129, and the front wheels 5 and 6 rear wheels. Increase the permissible amount of difference in rotational speed between 17 and 18. Further, when the difference in rotation speed between the front wheels and the rear wheels is large when the vehicle is traveling straight, this difference in rotation speed is not allowed and torque is transmitted to the rear wheels 17, 18.

Further, by inputting the manifold negative pressure into the transmission port 257 and interlocking the opening and closing of the atmosphere opening oil passage 129 with the torque of the engine, it is possible to appropriately switch to four-wheel drive according to the magnitude of the engine torque and the steering angle. can do.

However, since there is a significant pressure difference between the manifold negative pressure and the power steering oil pressure, it is necessary to use a considerably strong spring 259 to be used.

Also, depending on whether the brake hydraulic pressure is high or low, the atmosphere open oil passage 1
According to operating conditions such as a method of squeezing 29, a method of squeezing the air opening oil passage 129 according to the on / off operation of the accelerator,
The same purpose as described above can be achieved by using means for variably restricting the circulation of oil.

Further, it is possible to throttle the air opening oil passage 129 according to the traveling speed of the vehicle, the steering angular velocity, and the like.

Next, a fifth embodiment in which the oil pump 50 is a vane pump will be described with reference to FIGS. 10, 11 and 12.

The same parts as those already described are numbered and the description thereof is omitted.

Reference numeral 271 denotes a vane pump, and the pump main body includes a presser retainer 273, a cam ring 275, and a pump case 2.
And the front retainer 273 and the front retainer 273.
6 is spline-fitted to a sheath shaft 8'that is connected to a front wheel drive shaft 13 that transmits a driving force to the shaft 6.

The rotor 279 of the vane pump 271 is arranged in a space formed by the presser retainer 273, the cam ring 275, and the pump case 276, and is spline-fitted and connected to the rear wheel output shaft 19.

The rotor 279 is located eccentrically with respect to the cam ring 275, and a large number (here, nine) are provided on the outer peripheral portion of the rotor 279.
Are formed at equal intervals in the circumferential direction, and a vane 283 capable of sliding contact with the inner peripheral surface 275a of the cam ring 275 is fitted and inserted into each of the plurality of vane grooves 281, 281. ing.

Further, a plurality of (here, 4) clutch plates 73 for spline engagement are arranged on the outer peripheral portions of the presser retainer 273, the cam ring 275, and the pump case 276, which are equivalent to those already described in the first embodiment. Clutch mechanism 53
Is provided.

Also, as shown in FIG. 11, the pump case 276 is
Two ports 283 and 285 are formed, the oil passages 105 and 111 are connected to the port 283, respectively, and the oil passages 106 and 112 are connected to the port 285, respectively.

FIG. 12 shows an oil passage 125 with a relief valve 123.

The other hydraulic circuits and hydraulic control means are the same as the hydraulic circuit 51 and hydraulic control means 55 shown in FIG. 3 of the first embodiment.

The operation will be described below.

When a rotation speed difference occurs between the front wheel output shaft 13 side and the rear wheel output shaft 19 side, and the rotor 279 rotates in the direction of arrow a ′, oil is absorbed in the oil suction port 81, the oil passage 109, the check valve 108, After being sucked into the port 285 through the oil passage 106, it is discharged from the oil passage 115 through the port 283, the oil passage 111, and the check valve 113.

On the contrary, when the rotor 279 rotates in the direction of the arrow b ′, the oil flows into the oil suction port 81, the oil passage 109, and the check valve 1.
07, oil passage 105, and after being sucked into port 283, port 285, oil passage 112, check valve 114
And then discharged from the oil passage 119.

The discharged hydraulic pressure flows into the oil chamber 71, and the piston 65
Is pushed out and the clutch mechanism 53 operates.

As described above, even if the vane pump 271 is used as the oil pump 50, the same effect can be obtained.

In addition to the above description, other oil pumps may be similarly incorporated.

Next, a modified example of the hydraulic circuit 51, the hydraulic control means 55 and the oil pump 50 in the first embodiment of the present invention will be described as a sixth embodiment with reference to FIGS. 13, 14 and 15.

The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 13, a case 301 is spline-fitted to the sheath shaft 8 ′, and an oil pump 303 is provided in the case 301.

The oil pump 303 includes an inner gear 305 as an external gear that is spline-fitted to the rear wheel output shaft 19, and an outer gear 30 as an internal gear that is meshed with the inner gear 305 but is eccentric to the inner gear 305.
7, the inner gear 305 and the outer gear 307 are provided in the pump case 309.

In addition, the pump case 309 uses the bolt 311 to make
It is fixed to No. 1 and a part 309a of the pump case 309 is inserted in the gap between the inner gear 305 and the outer gear 307.

Further, as shown in FIG. 13, an annular step portion is formed on the outer periphery of the pump case 309, and a piston 306 is fitted in this step portion.

As a result, an oil chamber 308 (this is a clutch contact direction control side oil chamber) is formed between the piston 306 and the pump case 309.

Further, the clutch mechanism 313 includes a plurality of pressing plates 310 that are spline-engaged with the case 301 on the inner peripheral side,
The sleeve 312 with the rear wheel output shaft 19 is provided with a clutch plate 314 that is spline-engaged, and is alternately arranged.

Next, the hydraulic circuit 51 'will be described. Oil pump 3
03 has two ports 31 as shown in FIG.
5, 317 are formed, but one port 315
Is an oil intake port 8 that opens to the shaft end of the rear wheel output shaft 19 via an oil passage 321, which is a first oil passage, a check valve 323, which is a first intake check valve, and an intake oil passage 325.
Oil passage 32 that is connected to 1 and is a third oil passage.
7 and the first discharge check valve and the second discharge check valve through a three-way switching type check valve 329, which is connected to the discharge oil passage 331 in communication with the other port 3
Reference numeral 17 denotes an oil passage 333 which is a second oil passage, a check valve 335 which is a second intake check valve, and an intake oil passage 32.
5 is connected to the oil intake port 81 via the oil passage 5, and is also connected to the discharge oil passage 331 via the oil passage 337 which is the fourth oil passage and the three-way switching check valve 329. Further, between the oil passages 325 and 321, there is an oil passage 34 with a relief valve 339 which is a first release valve.
1 is interposed, and between the oil passages 325 and 333,
An oil passage 345 having a relief valve 343 which is a second relief valve is interposed.

From the oil passages 321, 333, 325, the first hydraulic circuit 34
4 from the oil passages 327, 331, 337
A hydraulic circuit 346 is formed.

Further, from the oil passage 327, an atmosphere opening oil passage 349 with an orifice 347 which is a first orifice is branched, and from the oil passage 337, an atmosphere opening oil passage 353 with an orifice 351 which is a second orifice is branched. .

The oil pressure control means 360 is formed by the orifice 347 and the relief valve 339 and the orifice 351 and the relief valve 343.

The reference numeral 363 in FIG. 13 indicates a stopper member.

Further, the oil passages 349 and 353 are provided so as to be directed to the compression plate 310 and the clutch plate 314 of the clutch mechanism 313, and the compression plate 310 and the clutch plate 3 are provided.
It is discharged toward 14.

Ports 315, 317, oil passages 321, 325, 327,
331, 333, 337, 349, 353, check valves 323, 335, relief valves 339, 343
The orifices 347, 351 and the three-way switching type check valve 329 are arranged in the pump case 309.

The discharge pressure characteristic A discharged from the oil passage 331 and the arrow b direction when the inner gear 305 rotates in the direction of arrow a shown in FIG. 14 due to the difference in rotational speed between the front wheel output shaft 13 and the rear wheel output shaft 19. FIG. 15 shows the discharge pressure characteristic B discharged from the oil passage 331 when rotating.

The operation by the above configuration is equivalent to the contents already described in the first embodiment, and the same effect can be obtained. Also, this 6th
The hydraulic control unit 360 of the embodiment may be controlled in the same manner as the contents described in the second, third, and fourth embodiments.

The power transmission device 13 of the present invention is not limited to the position shown in FIG. 1, but may be a modification shown in FIG.

In the schematic configuration diagram of the drive system of the seventh embodiment shown in FIG. 16, a transmission 403 is connected to an engine 401 installed vertically,
The rear wheel drive shaft 4 that transmits the driving force from the drive gear 407 attached to the output shaft 405 to the rear wheels 409 and 410.
11 is directly driven, and the driving force transmitted from the drive gear 407 is transmitted through the power transmission device 413 to the front wheels 41.
5, the front wheel output shaft 417, which transmits the driving force to the driving force, is driven. 419 is a differential device for the front wheels 321
Is a differential device for the rear wheels.

From the schematic structure of the drive system of the vehicle as described above, the rear wheel load becomes large in the case of sudden acceleration, the grip limit torque of the rear wheels 409, 410 becomes large, and most of the engine torque is taken over by the rear wheels 409, 410. The power transmission device 4 is moved to the front wheels 415 and 416 by the amount including the grip limit of the rear wheels.
It suffices to transmit the engine torque via 13, and the torque capacity to be received can be small, and the pump capacity and the clutch mechanism capacity can be reduced.

In addition, the engine torque can be directly applied to the rear wheel side where the grip limit torque becomes large, which has the effect of improving the acceleration performance.

[Brief description of drawings]

1 to 6 show a power transmission device as a first embodiment of the present invention. FIG. 1 is a schematic configuration diagram showing a power system of a vehicle equipped with this device, and FIG. 2 is a main part thereof. FIG. 3 is a vertical sectional view showing the hydraulic circuit for the oil pump, and FIG. 4 is a vertical sectional view showing the vicinity of the relief valve 123.
FIG. 5 is a schematic diagram showing the essential parts of the oil pump, FIG. 6 is a graph explaining its operation, FIG. 7 is a hydraulic circuit diagram showing a second embodiment of the present invention, and FIG. FIG. 9 is a vertical sectional view showing a third embodiment, FIG. 9 is a vertical sectional view showing a fourth embodiment of the present invention, and FIG. 10 is a vertical sectional view showing an essential part of a fifth embodiment of the present invention. Is a schematic diagram showing a main part of an oil pump of the fifth embodiment, and FIG. 12 is a relief valve 12 of the fifth embodiment.
3 is a vertical sectional view showing the third embodiment, FIG. 13 is a vertical sectional view showing the sixth embodiment of the present invention, and FIG. 14 is a hydraulic circuit diagram of the sixth embodiment.
FIG. 5 is a graph for explaining the operation of the sixth embodiment, and FIG. 16 is a schematic configuration diagram of the drive system of the seventh embodiment. 1 ... Engine, 2 ... Transmission, 3 ... Drive gear, 5, 6 ... Front wheel, 8, 8 '... Sheath shaft, 13 ... Front wheel output shaft constituting first rotary shaft, 16 ... Rear wheel output shaft constituting second rotary shaft, 15 ... power transmission device, 17, 18 ... rear wheel, 23 ... front wheel differential, 37 ... rear wheel differential, 50 ... oil pump, 51 ... ... hydraulic circuit, 52 ... transmission case, 53 ... clutch mechanism, 55 ... hydraulic control means, 54 ... first hydraulic circuit, 56 ... second hydraulic circuit, 57, 58 ... pump case, 59 …… Inner gear, 61 …… Outer gear, 65 …… Piston, 71 …… Oil chamber, 73 …… Clutch plate, 75 …… Precision plate, 77 …… An annular spring as an urging mechanism, 123 …… Relief valve , 127 …… Olihuis, T …… Power Itarukei

Claims (1)

[Claims] 1. A drive is performed by a difference in rotational speed between a first rotating shaft that transmits a driving force from an engine to which a transmission is connected to a front wheel of a vehicle and a second rotating shaft that transmits the driving force to a rear wheel of the vehicle. Oil pump that discharges the discharge pressure according to the same rotation speed,
A clutch mechanism that is interposed between the first rotary shaft and the second rotary shaft and that joins the rotary shafts by the discharge pressure of the oil pump, and a hydraulic pressure that supplies the discharge pressure from the oil pump to the clutch mechanism. And a hydraulic control means provided in the hydraulic circuit for controlling the discharge pressure to adjust the joining force of the clutch mechanism.