JPS62258822A - Four-wheel drive device - Google Patents

Abstract

PURPOSE:To simplify the structure and flatten the floor by driving a hydraulic motor with a drive system to one wheel from an engine interlockingly with the other wheel and controlling the hydraulic power according to the slip factor of the other wheel. CONSTITUTION:When a computer 6 judges that the slip factor (s) of wheels 1e, 1d exceeds a predetermined value based on the rotating speed of wheels 1e, 1d, 3b, 3c, a bypass valve 2h is closed, an actuator 2a is turned on, and the displacement volume of a hydraulic pump 2 is increased. Thereby, the hydraulic power is fed by pressure to a hydraulic motor 2f. Therefore, a load is applied to an engine 1, the engine output to the wheels 1e, 1d is decreased, the driving force of the wheels 1e, 1d is decreased. Simultaneously, the oil pressure in a pressure signal pipe 5b is increased, a driving force is generated in the hydraulic motor 2f via an actuator 2g, and the wheels 3b, 3c are driven via a drive shaft 3. Accordingly, the structure can be simplified.

Description

[Detailed description of the invention] [Industrial application field] TECHNICAL FIELD The present invention relates to a four-wheel drive device in an automobile.

[Prior Art] Conventionally, a four-wheel drive system in an automobile is capable of driving all four wheels, and therefore not only effectively exerts its driving or braking force when driving on slippery roads, but also effectively exerts its driving force or braking force when driving on slippery roads. It has been attracting particular attention in recent years due to its excellent steering stability.

The configuration of these four-wheel drive devices is such that output power from the engine mechanically drives the front wheels or rear wheels on the one hand via a transmission, and mechanically drives the rear wheels or front wheels on the other hand. It is structured as follows.

[Problems to be Solved by the Invention] However, as mentioned above, in these four-wheel drive devices, both the front wheels and the rear wheels are mechanically driven via the drive shaft. Its structure is extremely complex.

As a result, not only does the four-wheel drive system itself become complicated, but it also imposes various constraints on the design of the chassis, etc.
The design lacks flexibility, and in particular, the chassis requires a tunnel structure to accommodate the drive shaft, making it impossible to make the floor structure inside the vehicle a uniform flat structure. .

An object of the present invention is to provide a four-wheel drive device that eliminates the above-mentioned drawbacks and has increased design flexibility.

[Means for solving problems] The present invention has the following configuration.

The output power from the engine is configured to drive either the front wheels or the rear wheels via the main transmission.

A hydraulic pump is interlocked between the QA dynamic system extending from the engine to the one wheel side, and the hydraulic power output from the hydraulic pump is configured to drive hydraulic pressure, and the extraction pressure The output shaft of the motor is linked to either the front wheel or the rear wheel, and the hydraulic pump is configured to
When the wheel on the power side slips more than a predetermined value with respect to the road surface when the engine is running, the hydraulic power is transferred from the hydraulic pump to the hydraulic motor in proportion to the slippage. It consists of the following components:

[Operation] When a car is operated in a normal state, that is, when the engine drives the wheels on one side via the main transmission and the heavy wheels are in a slip ratio state between them and the road surface, the slip rate is within a predetermined allowable range. When the vehicle is running, the output power from the engine is driving one of its wheels through the main transmission.

Under these normal conditions, when the engine is running, if one of the wheels on one side slips more than a predetermined value on the road surface, the hydraulic pump will The hydraulic power from the hydraulic motor to the hydraulic motor is increased.

Therefore, in such a state where the wheels on one side are slipping, the hydraulic pump causes a load on the engine, so the driving force from the engine to the wheels on that one side decreases, and as a result, the The slippage between the wheels on one side and the road surface decreases.

Also, at this time, the hydraulic power from the hydraulic pump that caused the load on the engine drives the hydraulic motor, which in turn drives the wheels on the other side. Even if one of the wheels driven via the main transmission slips, the driving force for driving the vehicle will not be reduced.

[Example code] Hereinafter, the present invention will be explained based on Examples.

FIG. 1 shows a game in which a 4-striped betting station was installed on the system (support) as an embodiment of the present invention.

In FIG. 1, an engine l is connected to rear wheels 1e and 1 via a main transmission la, a drive shaft 1b, and a differential lc.
The hydraulic pump 2 is connected to the output shaft of the engine 1, and the hydraulic pump 2 is connected to the hydraulic pipe 2.
b and 2C to a hydraulic motor 2f, and the hydraulic motor 2f is linked to front wheels 3b and 3C via a drive shaft 3 and a differential 3a.
Two chain valves 2d and 2e are interposed between the check valves 2d and 2e, and a hydraulic pipe 2 is provided between the check valves 2d and 2e.
n is interposed, and a hydraulic signal pipe 5b communicates with the hydraulic pipe 2n.

Hydraulic pressure No. 48 pipe 5b is input to one input side of comparator amplifier 5, reference device 5a is input to the other input of comparator amplifier 5, output signal line 5C in comparator amplifier 5 is input to switch 5d and signal line 5e. It is input to actuator 2g via.

Moreover, a bypass valve 2 is provided between the hydraulic pipe 2b and the hydraulic pipe 2C.
The hydraulic pipe 2b is connected to the reservoir 4 via the valve 2k, and the hydraulic pipe 2C is connected to the accumulator 2m via the check valve 2j, and between the accumulator 2m and the hydraulic pipe 2C. A valve 21 is provided.

The output of the detector 6a that detects the rotational speed of the drive shaft 1b, and the detector 6b that detects the rotational speed of the drive shaft 3
is input to the calculator 6, and to the calculator 6, a signal from an accelerator pedal and a signal from a brake pedal (not shown) are input, and an actuator 2a that controls the displacement of the hydraulic pump 2, a hydraulic motor The actuator 2g, the switch 5d, the bypass valve 2h, and the valves 21 and 2, which control the displacement of the valve 2f, each have a calculator 6.
The structure is such that it is activated by each output signal from the.

In the structure of the embodiment of the present invention described above, the operation thereof will be explained below.

Operation during normal driving: When the automobile equipped with the four-wheel drive device shown in FIG. It's driving.

In this driving state, the calculator 6 detects the rotational speed of the drive shaft 1b and the rotational speed of the drive shaft 3 using the detectors 6a, 5, and 6b, and determines that the difference between the rotational speeds is within a predetermined range. For example, under normal conditions, the value obtained by dividing the difference between the rotational speed of the drive shaft 1b and the rotational speed of the drive shaft 3 by the rotational speed of the drive shaft 1b, that is, the slip ratio, is within 5 percent, for example. , the calculator 6 closes the valves 21 and 2k, opens the bypass valve 2h, and operates the actuator 2a to set the displacement of the hydraulic pump 2 to zero.

Also, in this state, the comparator amplifier 5
The difference (p-po) between the oil pressure p in the overpressure signal pipe 5b and a reference value po corresponding to the reference oil pressure (for example, 300 atmospheres) in the reference device 5a is calculated, and the comparison amplifier 5 calculates the difference (p-po).
A signal proportional to -p o) is sent to the actuator 2 via the signal line 5C1 switch 5d and the signal line 5e.
g.

In addition, in the comparison in the comparison amplifier 5, the temporal change in the oil pressure in the oil pressure signal tube 5b id p/d
t = p a, or it may be a circuit that takes into account the accelerator pedal depression speed Ay and compares the value obtained by adding the pa or Av to the above p with the reference value po, taking into account one phase advance. In the driving state, the calculator 6 switches the switch 5d to the normal state, that is, the signal line 5C with the sign of the signal on the signal line 5C unchanged.
conversely, when the brake pedal is depressed, the sign on the signal line 5C is converted to the opposite sign and is transmitted to the signal line 5e, and the signal on the signal line 5e is When the sign of the signal is positive,
The actuator 2g is actuated in the direction of increasing the displacement of the hydraulic motor 2f, and conversely, when the sign of the signal on the signal line 5e is negative, the actuator 2g is actuated in the direction of zeroing the displacement of the hydraulic motor 2f. , the speed of its operation is proportional to the value of the signal, and when the signal value is zero, the displacement of the hydraulic motor 2f is fixed at that position.

In this normal driving state, since the bypass valve 2h is open as described above, the hydraulic pipe 2b and the hydraulic pipe 2C are in a low pressure state of the same value, for example, charge pressure = about 5 atmospheres.

Therefore, in this state, the difference (p-po) becomes negative, and the actuator 2g decreases the displacement volume of the hydraulic motor 2f, but regardless of this decrease, the hydraulic pipes 2b, 2n and 2C remain at the same low pressure, so actuator 2g
is controlled until the displacement of the hydraulic motor 2f becomes zero, and in the steady state, the displacement of the hydraulic motor 2f remains zero.

That is, in this normal state, the displacement of the hydraulic pump 2 is set to zero as described above, and the displacement of the hydraulic motor 2f is also set to zero, so that the displacement from the hydraulic pump 2 to the hydraulic motor 2f is , hydraulic power is not being output, and as a result, the hydraulic motor 2f is not in a state to drive the wheels 3b and 3C via the drive shaft 3 and the differential 3a, and the hydraulic pump 2 and the hydraulic motor 2f are Since the hydraulic pipe 2b and the hydraulic pipe 2C are at the same low pressure value, there is no hydraulic load at all.

Effects when the drive wheels on the main drive side slip: The driving force applied to the wheels 1e and ld is too large, or the coefficient of friction between the wheels 1e and 1d and the road surface is reduced, causing the wheels to slip. 1e and lc
When slippage occurs between i and the road surface, wheels 1e and 1d
becomes higher than the rotational speed of the wheels 3b and 3C, and as a result, the calculator 6 calculates the slip rate S of the wheels 1e and ld from the rotational speed of the drive shafts 1b and 3, and the slip -US is When it is determined that the predetermined slip ratio SO (for example, 5%) has been exceeded, the calculator 6 closes the bypass valve 2h and at the same time operates the actuator 2a to increase the displacement volume of the hydraulic pump 2.
.

As a result, the hydraulic pump 2 starts discharging pressure oil to the hydraulic pressure W 2 b, and the hydraulic power is transferred to the hydraulic motor 2 through the hydraulic pipe 2°b.
It is ready to be pumped to f. Therefore, the generation of hydraulic power by the hydraulic pump 2 begins to place a load on the engine 1, and the output that the engine 1 has been producing to drive the wheels 1e and 1d via the main transmission 1a is reduced. .

Therefore, the reduction in the output from the engine 1 to the wheels 1e and 1e reduces the driving force of the wheels 1e and ld with respect to the road surface, and as a result, the slip ratio S between the wheels is and lcl and the road surface decreases.

Further, as described above, as the hydraulic pump 2 increases the load on the engine l, the hydraulic pump 2 increases the hydraulic pipe 2b,
The oil pressure in the oil pressure signal pipe 5b is increased via the check valve 2e and the oil pressure pipe 2n.

In this case, as mentioned above, until now the displacement of the hydraulic motor 2f has been zero, so the pressure oil discharged from the hydraulic pump 2 has nowhere to go, and its oil pressure p increases, and eventually its When the oil pressure p becomes smaller than the reference value pO in the reference device 5a, the difference (p-po) becomes positive, so that the 7-piece motor 2g increases the displacement volume of the hydraulic motor 2f. As a result, a torque that drives the drive shaft 3 is generated in the hydraulic motor 2f, and this torque drives the wheels 3b and 3c via the drive shaft 3 and the differential 3a.

Therefore, even if the wheels 1e and 1d slip on the road surface, the slippage is reduced, and at the same time, the driving force from the wheels 3b and 3C increases, increasing the driving force of the entire vehicle. keeping.

In this case, the rotational speed of the hydraulic pump 2 is n
p, its displacement volume is Dp, the rotation speed of the hydraulic motor 2f is nm, and its displacement volume is Dm, then the pressure oil discharge amount Qp from the hydraulic pump 2 is as follows: Qp=npXDp (1), and the hydraulic pressure The pressure oil flow rate Qtn flowing into the motor 2f is Qm=nmXDm (2),
Assuming that the leakage loss between the hydraulic pump 2 and the hydraulic motor 2f is zero, from the continuous condition.

Qp=Qm needs to be satisfied, i.e. (1) and (2
), it follows that the condition npXDp=nmXDm or Dm=(npXDp)/nm (3) needs to be satisfied.

Therefore, in the above operation, when the displacement @' product Dm in the hydraulic motor 2f is about to increase beyond the condition of equation (3), the hydraulic pressure P in the hydraulic pipe 2b, that is, the hydraulic pressure in the hydraulic signal pipe 5b. As p decreases, the difference (p-po) becomes a negative value.

However, as mentioned above, the comparison amplifier 5
) is determined to be negative, a negative signal is directly given to the actuator 2g, and as a result, the actuator 2g decreases the displacement volume Dm. hydraulic p
This has the effect of making it equal to the reference value po in the reference device 5a.

In addition, in the above-described operation in which the hydraulic motor 2f drives the wheels 3b and 3C, if the rotational speed of the drive shaft 3 suddenly increases, the calculator 6 detects that there is slippage between the wheels 3b and 3C and the road surface. Assuming that this has occurred, the displacement volume of the hydraulic pump 2 is decreased, and the hydraulic driving force of the wheels 3b and 3C is decreased to prevent the slippage from increasing.

Effects during engine braking: When the accelerator pedal is released quickly or the brake pedal is depressed, the following effects occur.

In the process of depressing the accelerator pedal from a state where the accelerator pedal is depressed, there is a state where the driving force decreases from the state where the wheels 1e and ld are being driven to zero, and such driving force becomes zero. When this is the case, the wheels 1e and ld do not slip on the road surface.
Therefore, when the driving force is zero, the displacement volumes of the hydraulic pump 2 and the hydraulic motor 2f are both zero, as described above.

In this way, when the accelerator pedal is quickly released or the brake pedal is depressed, the calculator 6 switches the switch 5d from the drive state to the carrot brake state.

Also, in this case, the calculator 6 keeps the bypass valve 2h, valves 21 and 2k closed.

Moreover, the displacement volume of the hydraulic pump 2 is kept set to zero.

As a result, immediately after entering the engine brake, no hydraulic power is output from the side of the hydraulic pump 2, which has a large displacement, and the operating pressure of the hydraulic pipe 2b or 2C becomes a high pressure. Not standing up.

Therefore, the difference (p-po) in the comparison amplifier 5 becomes a negative value, and the negative signal on the signal line 5C is converted into a positive value signal in the switch 5d and sent to the signal line 5e. The actuator is attempted to be increased by the signal on the signal line 5e, which is transmitted and, as a result, becomes a positive signal.

However, since the displacement of the hydraulic pump 2 is zero in this state 7g, the displacement of the hydraulic motor 2f needs to satisfy the condition of equation (3), and the displacement of the hydraulic motor 2f is almost zero in the range of values close to zero. 2c side is maintained at the reference oil pressure of the reference device 5a.

In this case, the displacement of the hydraulic pump 2 is zero, and the wheels 3b and 3c are rotated by the running inertia of the car, so the hydraulic motor 2f is driven by the running energy g- of the wheels 3b and 3C. Since the hydraulic motor 2f is in a driven state, if the displacement of the hydraulic motor 2f is even slightly large, the hydraulic motor 2f will perform a pumping action, which is the opposite of what it does when it is driven. Hydraulic pipe 2C is the high pressure side.

Conversely, the hydraulic pipe 2b becomes the low pressure side, and the hydraulic pressure P on the hydraulic pipe 2c side is transmitted to the hydraulic signal pipe 5b via the check valve 2d and the hydraulic pipe 2n. In this engine braking state, for example, the mechanical transmission As a result of setting 1a to a low gear ratio and applying strong engine braking, the engine braking is too strong, causing slippage between wheels 1e and 1d and the road surface, and the slip rate S due to this slipping exceeds a predetermined value. When , the calculator 6 is.

The displacement volume of the hydraulic pump 2 is increased by operating the actuator 2a.

As a result, the comparator amplifier 5 increases the displacement of the hydraulic motor 2f so as to maintain the relationship of equation (3) and maintain the hydraulic pressure p in the hydraulic signal pipe 5b at the reference value.

This means that since the output of the engine 1 is decreasing, as described above, the hydraulic motor 2f is driven from the wheels 3b and 3c side, and the hydraulic motor 2f performs a pumping action.
Since the hydraulic pump 2 is in a state where it acts as a motor and the displacement volume of the hydraulic pump 2 increases, the power that drives the hydraulic pump 2 from the hydraulic motor 2f side increases.

That is, 11 (the hydraulic motor 2 is also connected to the wheels 3b and 3C side)
Engine braking is applied to the engine 1 through the purely hydraulic drive system of the hydraulic pump 2 and the hydraulic pump 2, reducing the slippage of the wheels 1e and 1d during engine braking, and effectively applying engine braking. I'm going to go to the middle of the day.

Also, in this case of engine braking.

Since the pressure in the hydraulic pipe 2C becomes high, the pressure oil accumulates in the accumulator 2m via the check valve 2j.

In the above operation, fuel may not be supplied to the carrot 1 when the accelerator pedal is released to apply engine braking, or when the vehicle is stopped at an intersection or the like.

In this way, when fuel is not being supplied to the engine 1, the engine 1 is connected to the wheels 1e, 1d, 3b, and 3c.
When the engine 1 is disconnected from the rotation of the hydraulic motor 2f, the operation of the engine 1 will stop; however, when it becomes necessary to restart the engine 1, the calculator 6 sets the displacement volume of the hydraulic motor 2f to zero. If the displacement of the hydraulic pump 2 is increased, and the valve 21 is opened at the same time as the calculator 6 opens the valve 2k, the pressure oil in the accumulator 2m will flow through the valve 21 and the hydraulic pipe 2c. The hydraulic pump 2 is driven by the hydraulic pump 2, and the hydraulic pump 2 starts the engine 1 by the driving. Further, the pressure oil that has driven the hydraulic pump 2 further flows to the reservoir 4 via the hydraulic pipe 2b and the valve 2k.

Furthermore, when the vehicle is accelerating, the pressure oil in the accumulator 2m may be sent under pressure to the hydraulic pipe 2b in the above-mentioned acceleration state to reuse braking energy.

Effects when starting on a slope: When the vehicle is ready to start on a slope, the calculator 6 sets the hydraulic pump 2a to the neutral state so that the wheels 1e and 1d slip during the above-mentioned drive, and at the same time sets the hydraulic pump 2 to the neutral state. The operation is linked to the accelerator pedal.

In this set state, the drive system of the automatic tank is the same as the normal pure hydraulic drive configuration consisting of the hydraulic pump 2 and the hydraulic motor 2f.

By slightly pressing the accelerator pedal, it is possible to stop the vehicle on the slope.

In other words, if the car is about to go backwards, if you slightly press the accelerator pedal, the displacement of the hydraulic pump 2 driven by the idling engine 1 will increase, and the displacement will increase. In conjunction with this, the comparator amplifier 5 increases the displacement volume of the hydraulic motor 2f, so the hydraulic motor 2f supports the force that attempts to move the car down the slope.

In this case, since the car is stopped, the rotation of the hydraulic motor 2f is zero and the rotation force is 1).
Also, since the pressure oil from the pressure pump 2 is fed to the hydraulic motor 2f, the hydraulic motor 2f rapidly increases its displacement volume in order to satisfy the relationship of equation (3). This causes the hydraulic motor 2f to generate a large torque capable of holding the vehicle on the slope.

Furthermore, since the amount of pressure oil generated from the hydraulic pump 2 in this case is very small, the amount of heat generated by the pressure oil as a whole is very small.

When starting on a slope from this state, if you press the accelerator pedal hard in this state,
In the state of pure hydraulic drive, when the car starts and reaches the appropriate speed of the car, the calculator 6 calculates the following:
The drive mode is then switched to a drive state using the above-mentioned main transmission 1a.

Effect of parking in the garage 2 In the pure hydraulic drive state described above, if the accelerator pedal is gently depressed, the hydraulic pump 2 and hydraulic motor 2
Since the relationship with f is that of a completely continuously variable transmission, the car can be driven smoothly and at the slow and safe speed necessary to park the car in the so-called creeping state. It becomes possible to do so.

Therefore, even drivers with low skill can easily get +17.
You will be able to stock it.

In the above embodiment, the displacement of the hydraulic pump 2 is controlled by the calculator 6, and the displacement of the hydraulic motor 2f is controlled by the comparison amplifier 5. However, to control these displacement volumes, the hydraulic pump 2 side is controlled by the comparator amplifier 5 so that the working oil pressure p=constant, and the hydraulic motor 2f side is calculated 5°''
j″r [ti t= x+”+64”52ゝ15°゛,・1 Figure 2 shows an example of such a case,
This system diagram shows only the part that controls the displacement of the hydraulic pump 2 and the hydraulic motor 2f, and the difference from FIG. 1 is that the displacement of the hydraulic pump 2 is controlled by the comparator amplifier 5. The configuration is such that the displacement of the hydraulic motor 2f is controlled by the calculator 6, and the symbols used in FIG. 2 are the same as those in FIG. 1. are indicated by the same reference numerals.

Operation during driving in Fig. 2: In a normal state where there is no slippage between the road surface and the wheels 1e and 1d, the bypass valve 2h is opened and the hydraulic pipe 2
b is bypassed to the hydraulic pipe 2c, and the switch 5d
is set in the normal state, that is, the state in which the signal No. 48 of the signal line 5c is transmitted to the signal line 5e with the same sign, and the displacement of the hydraulic motor 2f is calculated using the calculator 6.
is set to a value of zero.

In this way, when the hydraulic pipe 2b and the hydraulic pipe 2C are in a bypassed state, the hydraulic pressure p of the hydraulic pipe 2n is in a low pressure state, so the comparative amplification 91 ζ I# I-
)! True symbol f, -sail ^) 1↓ picture --m right b nn --1.

Therefore, in this normal state, the signal line 5
Due to the negative signal at e, the displacement of the hydraulic pump 2 is set to zero, and no hydraulic power is generated between the hydraulic pump 2 and the hydraulic motor 2f.

In such a state, slippage occurs between the road surface and the wheels 1e and ld, and when the slip ratio reaches a predetermined value or more during the slippage, the calculator 6 closes the bypass valve 2h and switches the switch 5d. The relationship between the signal on the signal line 5C and the signal on the signal line 5e is set to have opposite signs.

As a result, the displacement of the hydraulic motor 2f is still zero, and at the moment of switching, the hydraulic pressure P of the hydraulic pipe 43 pipe 5b is in a low pressure state as described above, so the signal line 5C is The difference (p-po) remains a negative value, and as a result, the value of the signal on the signal line 5e becomes positive, and the displacement in the hydraulic pump 2 is ready to increase. While satisfying the relationship of formula (3), the hydraulic pressure P of the hydraulic pipe 2b is set to the reference value po.
be equal to

Immediately after switching the switch 5d, the calculator 6
An instruction signal is issued to the actuator 2g, and the displacement of the hydraulic motor 2f is increased in proportion to its slip ratio. The displacement volume is calculated so that the relationship of equation (3) is satisfied.
Make it bigger.

That is, the hydraulic power supplied from the hydraulic pump 2 to the hydraulic motor 2f increases in proportion to the increase in the slip ratio.

Effects during engine braking in Fig. 2: As explained in Fig. 1, when the accelerator pedal is returned from the depressed state, at least the wheels 1e
and 1d do not slip on the road surface, and the driving torque is zero.

Therefore, the initial state when this engine brake is applied is
The hydraulic power between the hydraulic pump 2 and the hydraulic motor 2f is zero.

As the accelerator pedal is quickly released, the calculator 6 sets the switch 5d to the normal state, that is, the signal on the signal line 5c and the signal on the signal line 5e have the same sign. When the wheels 1e and 1d slip on the road surface while the brake is applied, the calculator 6 increases the displacement volume of the hydraulic motor 2f in proportion to the slip ratio.

Here, in this engine brake state jg, the output of the engine 1 decreases and the displacement of the hydraulic pump 2 is zero in its initial state, so the displacement of the hydraulic motor 2f increases. The hydraulic motor 2f performs a pumping action, and as a result,
The hydraulic pipe 2c side has a high operating pressure, and the hydraulic pipe 2b side has a low pressure side.

In this way, the hydraulic pressure P increased in the hydraulic pipe 2c is transmitted from the hydraulic pipe 2n to the hydraulic signal pipe 5b, and when the hydraulic pressure p becomes larger than the reference value po, the difference (p
-po) becomes positive, and as a result, the displacement of the hydraulic pump 2 increases, and this increase satisfies the relationship of equation (3) while increasing the displacement, and in the case shown in FIG. Similarly, the hydraulic pump 2 is connected to the hydraulic motor 2.
f, and the hydraulic pump 2 drives the engine l to apply engine braking.

In addition, FIG. 3 shows the comparison amplifier 5 in the embodiment described below.
The system diagram shows the configuration when the switching device 5d and the actuator 2g (or the actuator 2a) are hydraulically controlled.

In FIG. 3, the servo valve 50 corresponds to the comparator amplifier 5, and the spring 50a in the servo valve 50 corresponds to the reference device 5a.
, the spring setting force of the spring 50a when the spool valve 50b is in the equilibrium position shown in FIG. 3 corresponds to the reference value pO, the switching valve 51 corresponds to the switching device 5d, and the hydraulic actuator 52 corresponds to , corresponds to actuator 2g or 2a.

The effect of FIG. 3 is as follows.

The state in which the switching valve 51 is set to the normal switching position 51A corresponds to the state in which the signal on the signal line 5c and the signal on the signal line 5e are set to have the same sign in FIG. 1 or 2. I, spool valve 5 as above
When 0b is at the position shown in FIG. 3, it indicates an equilibrium state in which the oil pressure P of the oil pressure signal pipe 5b is equal to the reference value po.

When the oil pressure p of the oil pressure signal pipe 5b increases from this equilibrium state, the oil pressure P moves the spool valve 50b to the left against the applying force of the spring 50a.
Pressure oil is sent to the displacement chamber 52b in the hydraulic actuator 52 via the switching valve 51, and the pressure oil presses the piston 52a to the right, and due to the pressure, the piston 52a displaces the actuator 2g or 2a. The pressure oil that is displaced in the displacement chamber 52c due to the increased volume is transferred to the switching valve 5.
1 and servo valve 50 to the reservoir 4. On the other hand, the oil pressure p in the oil pressure signal pipe 5b is equal to the reference i! Ap
o, the spool valve 50b is moved to the right by the biasing force of the spring 50a, and as a result, the pressure oil from the hydraulic source 50c is forced into the displacement chamber 52c in the hydraulic actuator 52 via the switching valve 51. , the pressure oil sent under pressure presses the piston 52a to the left, and due to the pressure, the piston 52a moves toward the actuator 2g.
Alternatively, the displacement volume of 2a is decreased, and the pressure oil displaced in displacement chamber 52b by this action is discharged to reservoir 4 via switching valve 51 and servo valve 50.

Furthermore, as a result of controlling the hydraulic actuator 52 in this way, when the hydraulic pressure P in the hydraulic pressure 1.1 return pipe 5b is corrected to the base q and the value pO as explained in FIG. 1, the difference (p -po) becomes zero, the spool valve 50b returns to the illustrated equilibrium position.

, for the above action, by the signal from the calculator 6, !
, when the solenoid 51a in the I3 switching valve 51 is excited, its switching position is switched from 51A to 51B, and as a result, the direction in which the displacement of the hydraulic actuator 52, the hydraulic pump 2, or the hydraulic motor 2f is changed is as follows.
This is the opposite of the above case. In this case, it is the same as switching the switch 5d in FIG. 1 or 2[4 to make the signal on the signal line 5C and the signal on the signal line 5e have opposite signs.

In addition, in the following embodiments, wheels 1et-j and
, j and 1d are on the rear wheel side, and the wheels 3b and 3C are on the front wheel side. However, this configuration may be conversely made so that the wheels 1e and 1dt are on the front wheel side and the wheels 3b and 3C are on the rear wheel side.

[Effects of the Invention] As is clear from the above description, the effects of the present invention are as follows.

The output power from the engine is configured to drive either the front wheels or the rear wheels via the main transmission, and the other wheel is driven by pure hydraulic drive.1) Only one wheel side would require a drive shaft, and the drive to the other wheel side could be driven by a freely arranged hydraulic line, thus the engine on the wheel side driving through the main transmission. By installing this, it is no longer necessary to provide a tunnel for the conventional drive shaft in the chassis in order to drive the wheels on the other side, and it becomes possible to design a larger interior of the vehicle.

2) In addition, pure hydraulic drive is only activated when the wheels driven via the main transmission slip more than a predetermined value with respect to the road surface. When using a hydraulic drive, the pure hydraulic drive is not used all the time, but only when slippage occurs, resulting in reduced engine fuel efficiency due to poor transmission efficiency in the pure hydraulic drive. Almost no deterioration occurs.

[Brief explanation of drawings]

FIG. 1 shows a four-wheel drive device according to the present invention in a system diagram, FIG. 2 shows another embodiment around the comparator amplifier 5 in FIG. 1 in a system diagram, and FIG. This is a system diagram showing a case where the related configuration is performed by a hydraulic system. The main symbols used in the examples are as follows. 1: Engine, LA: Main transmission, LB: Drive shaft, LC: Differential, LE and LD: Wheels, 2
: Hydraulic pump, 2a and 2g: 7 units,
2f: Hydraulic motor, 3: Drive, 5: Comparison tank l1
liil device, 5a: reference device, 6: meter'i'7 device, 6 aq and 6b: detector. Patent Applicant: Takashi Miyao Proceedings of Ichisho Furushi I Case Description 1985 Patent Application No. 103381 2 Name of Invention 4-wheel drive device 3 Person making amendments Relationship with 215 cases Patent Applicant 4 Date of amendment order Spontaneous amendment 5 Subject of amendment (1) Detailed explanation of the invention column 6 in the written document 6 Contents of the amendment As shown in the attached sheet - (1) Amendment to the detailed explanation column of the invention in the specification 1) Description On the 16th page, insert the following sentence between the 5th and 6th lines. "In the action described in F, when the slip ratio S returns to within the predetermined slip ratio SO as a result of the hydraulic motor 2f driving the drive shaft 3 as described above, the calculator 6
a to return the displacement volume Dp of the hydraulic pump 2 to zero, open the bypass valve 2h, and operate the drive wheels 1e and 1.
d returns to the above-mentioned normal state in which there was no slippage on the road surface. Note that when the displacement Dp of the hydraulic pump 2 is returned to zero, the hydraulic motor 2f
The displacement volume Dm is set to zero. "that's all

Claims (1)

[Scope of Claims] 1. The output power from the engine is configured to drive either the front wheels or the rear wheels through a main transmission, and the output power from the engine is transmitted to the side of the one wheel. A hydraulic pump is interlocked between the drive system leading to the hydraulic pump, and the hydraulic power output from the hydraulic pump drives a hydraulic motor, and the output shaft of the hydraulic motor is connected to one of the front wheels or the rear wheels. , is interlocked with either the other side, and when the wheels on the one side slip more than a predetermined value with respect to the road surface while the engine is driving, the hydraulic pump pumps the hydraulic pump in proportion to the slippage. , increasing the hydraulic power from the hydraulic pump to the hydraulic motor. A four-wheel drive device having the above configuration.