JPH11108181A - Drive control system for vehicle having hydraulic motor for running and fluid control device with flow dividing function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system of a simple and low-cost configuration to perform a restriction of differential motion of the driving front and rear wheels or the left and right wheels of a vehicle which uses a hydraulic motor for running. SOLUTION: In the differential motion restricting mode to be in effect when the traction force of either of the driving wheels of a vehicle has decreased, a solenoid type opening/closing valve 18 opened in the normal condition is energized to the closed position, and the working fluid flowing from a variable displacement hydraulic pump 16 is distributed to hydraulic control units 24 and 26 constituting a fluid control device 22 equipped with a flow dividing function in such a proportion as complying with their displacement volume ratios, and a diveded flow is sent forcedly to associate hydraulic motors 12 and 14 via these control units. The pressure at the working oil outlet of the control unit 24 is in inverted proportion to that of the other control unit 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control system for a vehicle having a hydraulic motor for traveling and a fluid control device with a flow dividing function of the type used in the system.

[0002]

2. Description of the Related Art For example, in a four-wheel drive system of an automobile, in general, a driving force is distributed between front and rear wheels in order to constantly transmit the driving force to all the wheels, and at the same time, a rotational difference therebetween is reduced. A center differential or a differential device for absorbing is provided, and further, even if one of the front and rear wheels slips and loses its driving force, a differential lock mechanism or a differential limiting device for transmitting the driving force to the other wheel and A mechanical auxiliary speed change mechanism for switching between a high speed and a low speed is provided.

On the other hand, some industrial vehicles such as tractors, construction vehicles, agricultural vehicles and various other working vehicles used for a specific application include loads, for example, near each of driving wheels for traveling. In many cases, a hydraulic motor is provided in the vehicle body in operative connection with the wheels, and hydraulic oil is supplied to each hydraulic motor by a drive hydraulic circuit including a variable displacement pump to cause the vehicle to travel. In such a hydraulic motor utilization system,
The vehicle has a high degree of freedom in design. This is because power can be transmitted by hydraulic piping and a mechanical power transmission device whose installation conditions are relatively strict is not used. As is well known to those skilled in the art, hydraulic drive systems for these types of vehicles conventionally have a displacement or capacity (cm ³ / rev) to switch between a high-speed low-torque stage and a low-speed high-torque stage.
Some use an expensive two-speed hydraulic motor capable of internally changing the hydraulic pressure and a branch / collection valve for branching and supplying hydraulic oil to each hydraulic motor. A heavy-duty or heavy-duty vehicle requires a heavy-duty hydraulic source, and accordingly the hydraulic equipment has a large capacity, resulting in an increase in cost.
Further, in such a conventional hydraulic circuit system, there is a hydraulic circuit configured with a complicated two-speed circuit composed of a series and a parallel circuit, and performing a differential limitation by switching to a series circuit as necessary. There was a drawback that only high-speed, low-torque output could be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control system that uses a simple and inexpensive configuration to limit the differential between front and rear wheels or left and right wheels for driving a vehicle using a traveling hydraulic motor.

Another object of the present invention is to use an inexpensive one-speed hydraulic motor, which can be switched between two stages of high-speed, low-torque and low-speed, high-torque, and using a light-load hydraulic source. An object of the present invention is to provide a control system capable of obtaining a load class output torque.

It is a further object of the present invention to provide a fluid control device having a flow dividing function of a type used in such a hydraulic control system for a vehicle.

[0007]

SUMMARY OF THE INVENTION In view of the above objects, the gist of the present invention is a drive control system for a vehicle having a traveling hydraulic motor, which comprises a variable displacement hydraulic pump and a first vehicle drive system. A first hydraulic motor operatively connected to the load, a second hydraulic motor operatively connected to the second load of the vehicle, and a first and a second hydraulic motor for flowing hydraulic fluid from the hydraulic pump. A first valve, preferably an electromagnetic on-off valve, operable between a normal open position that can be guided to a hydraulic motor and a closed position that shuts off the same, and located downstream of the first valve; Means for passively diverting the flow of hydraulic oil from the hydraulic pump to the first hydraulic motor and the second hydraulic motor;
A fluid control device having a flow dividing function for receiving hydraulic oil from the hydraulic pump when the first valve is in the closed position, the fluid control device comprising: A first hydraulic control unit and the other of the first and second hydraulic motors in fluid communication with one of the second hydraulic motors and having a first displacement volume and a first hydraulic oil outlet pressure. A second hydraulic control unit in fluid communication and having a second displacement volume and a second hydraulic oil outlet pressure, wherein the first hydraulic control unit and the second hydraulic control unit Hydraulic oil flow is first
And the first and second hydraulic control units are operatively associated with each other so as to be distributed to the first and second hydraulic control units in accordance with the displacement volume ratio of the first and second hydraulic control units, respectively. In the open position, the flow of the hydraulic oil from the hydraulic pump is divided into the first hydraulic motor and the second hydraulic motor by the passive diversion means via the first valve, and the flow of the first or second load is reduced. When one of the traction forces decreases, the first valve is operated to the closed position to switch from the differential mode to the differential limiting mode, and the flow of the hydraulic oil from the hydraulic pump is reduced by the first of the fluid control device. And the second hydraulic control unit is distributed according to the displacement volume ratio, and is actively diverted to the associated hydraulic motor via the first and second hydraulic control units.
Wherein the first hydraulic oil outlet pressure of the hydraulic control unit and the second hydraulic oil outlet pressure of the second hydraulic control unit are in an inversely proportional relationship.

In the differential mode, the passive shunting means comprises a first
In the differential opening mode, the first hydraulic control unit of the fluid control device takes the first open position to divide the flow of the hydraulic oil from the first valve into the first hydraulic motor and the second hydraulic motor. An electromagnetic on-off valve may be operated at a closed position that isolates a hydraulic oil flow portion to the hydraulic motor and a hydraulic oil flow portion from the second hydraulic control unit to the second hydraulic motor, Takes a normal operating position in which the flow of hydraulic oil from the first valve is diverted to the first hydraulic motor and the second hydraulic motor, and in the differential limiting mode, the first hydraulic control unit of the fluid control device A hydraulic oil flow portion to the associated hydraulic motor that is operated to an operating position to communicate the second hydraulic motor and to communicate the second hydraulic control unit with the first hydraulic motor; Related to May be an electromagnetic control valve operable between a closed isolating the hydraulic fluid flow section of the pressure motor together position.

Preferably, the control system according to the present invention is provided in series with the hydraulic control unit downstream of one of the first and second hydraulic control units of the fluid control device, wherein the one hydraulic control unit is provided. A switching valve operable between an open position for fluid communication between the unit and an associated hydraulic motor, and a drain position for communicating the one hydraulic control unit to a low pressure source and increasing the outlet pressure of the other hydraulic control unit. It further has. Thus, in the differential / pressure-increasing mode, the first valve is operated to the closed position and the switching valve is operated to the drain position, and the flow of hydraulic oil from the hydraulic pump is controlled by the first and second fluid control devices. The hydraulic oil flow portion distributed to the hydraulic control unit according to the displacement volume ratio and distributed to the one hydraulic control unit is drained to a low pressure source through a switching valve and distributed to the other hydraulic control unit. The hydraulic oil flow portion is increased in pressure and is divided by the passive hydraulic diversion means into a first hydraulic motor and a second hydraulic motor. In this case, the passive diversion means diverts the hydraulic oil flow portion distributed to the other hydraulic control unit whose pressure has been increased to the first hydraulic motor and the second hydraulic motor in the differential / pressure-increasing mode. Preferably, it is in the open position.

Further, the gist of the present invention is a fluid control device used for a vehicle having at least a pair of traveling hydraulic motors and capable of shunting hydraulic oil to each traveling hydraulic motor, A hollow casing with a second opposing end face, each of which is sealingly and firmly attached to the first and second end faces of the casing, respectively, and passes through a flange plate having a through hole and a through hole; A hydraulic transmission unit including a rotatable transmission shaft extending outwardly and in an oppositely aligned state; and a transmission shaft located in the casing and having both ends rotatably and rotatably with respect to a flange plate of the hydraulic control unit. It is supported substantially concentrically and is firmly connected to the outer ends of the two transmission shafts so that it can rotate integrally with the two transmission shafts. In fluid control apparatus characterized by comprising a coupling member which has become. Such a hydraulic control unit is substantially identical in configuration to any conventional hydraulic motor having a transmission shaft or an output shaft. Typically, such a hydraulic motor includes a tooth-shaped member moving mechanism type hydraulic motor, a gear motor, a vane pump, and the like.

In one embodiment of the present invention, each of the hydraulic control units of the fluid control device is provided in the first tooth member with an internal tooth, and is planetarily movable with respect to the first tooth member. A second tooth profile member having a plurality of external teeth, a tooth profile member moving mechanism portion having a plurality of volume chambers formed between the internal teeth and the external teeth, and a gear portion mechanism portion via a valve plate. A valve housing adjacent and fixed thereto and having an inlet port and an outlet port, and housed in the valve housing, for introducing hydraulic oil from the hydraulic pump into the volume chamber through the inlet port. A valve device including a rotatable valve element operable to direct hydraulic fluid in the volume chamber to the outlet port. The inner end of the transmission shaft is splined to the splined hole of the second tooth member, and the flange plate is disposed adjacent to the tooth member moving mechanism on the side opposite to the valve plate and is located opposite the valve housing. And an inlet port of the valve housing of each hydraulic control unit can be in fluid communication with the discharge side of the hydraulic pump, and one outlet port of the first and second hydraulic control units has first and second hydraulic control units. One of the motors and the other outlet port of the first and second hydraulic control units can be in fluid communication with the other of the first and second hydraulic motors, respectively. And distributed into the inlet port of the second hydraulic control unit according to the displacement volume ratio determined by the volume chamber, and flows through each outlet port of each hydraulic control unit. It is adapted to be diverted to the hydraulic motor associated.

Preferably, the coupling member is a hollow cylindrical sleeve shaft having both ends opened to receive the outer ends of the transmission shafts of the first and second hydraulic control units, and the sleeve shaft has an inner periphery thereof. Portion is splined to the outer end of the transmission shaft. Preferably,
The sleeve shaft has at least two lateral through-holes in a part of its cylindrical wall, and a low-pressure space is defined between the sleeve shaft and the casing surrounding the sleeve shaft. In order to lubricate the connection between the inner peripheral portion of the sleeve shaft and the outer end portion of the transmission shaft, the sleeve circulates through the lateral through hole of the sleeve shaft. It is preferable to provide a spacer in the hollow portion of the sleeve shaft between the outer ends of the transmission shafts of the first and second hydraulic control units opposed to each other to maintain a distance between the outer ends of the transmission shaft.

The above features and advantages, as well as other features and advantages of the present invention, will become apparent to those skilled in the art upon reading the following detailed description of exemplary embodiments with reference to the accompanying drawings.

[0014]

FIG. 1 shows a vehicle hydraulic drive control circuit 10 embodying the principles of the present invention in various operating modes. More specifically, the division diagrams (A), (B),
(C) shows the hydraulic circuit 10 and its components in a differential mode, a differential limiting mode, and a differential / pressure-increasing mode, respectively. The circuit 10 includes, as major components, a hydraulic motor 12 operatively connected to a first load (not shown) and having a suitably selected displacement volume, a second load (not shown). A hydraulic motor 14 having an appropriately selected displacement volume, and a variable displacement hydraulic pump 16 adapted to be driven by an engine (not shown). Each of the first load and the second load may be, for example, a pair of front wheels and a pair of rear wheels of a construction vehicle using a traveling hydraulic motor. In this case, as shown in FIG. 2, the first hydraulic motor is composed of, for example, two hydraulic motors operatively connected to a pair of front wheels of the vehicle and hydraulically connected to each other in series. May comprise two hydraulic motors operatively connected to a pair of rear wheels of the vehicle and hydraulically connected to each other in series. Also, the first
May be, for example, the left side of a pair of front wheels of the vehicle, and the second load may be the right front wheel of the vehicle. Furthermore, the first
May be, for example, the left side of the pair of rear wheels of the vehicle, and the second load may be the right side of the pair of rear wheels of the vehicle. The displacement volumes of the hydraulic motors 12 and 14 may be different from each other or may be the same. Generally, the hydraulic motors 12, 1
The displacement volume of 4 differs depending on the design sharing load when the load associated therewith is the front wheel and the rear wheel, respectively, and is generally the same for the left and right wheels. The hydraulic motors 12 and 14 may be of any type. For example, the toothed member moving mechanism type ("Jiroller set" or "Girotor set") described in Japanese Patent Publication No. 56-19478 may be used. (Sometimes called a hydraulic motor). In this type of hydraulic motor, the tooth profile moving mechanism can be easily replaced with a desired displacement volume size. An example of this type of hydraulic motor is available as, for example, the Orbit motor 2000 series manufactured and sold by the present applicant.

As shown in the figure, an electromagnetic on-off valve 18 is provided which can be operated between a normal open position in which the flow of hydraulic oil from the hydraulic pump 16 can be directed to the hydraulic motor and a closed position in which it is shut off. Have been. Also, the on-off valve 18
Hydraulic fluid in the hydraulic line 32 from the hydraulic motor 1
The diversion means 20 which can passively divert according to these displacement volume ratios are provided in 2,14. The flow dividing means is preferably an electromagnetic on-off valve, and as a modification, for example, a 4-port 2-position electromagnetic switching valve may be used. Further, in the hydraulic circuit 10, a fluid control device 22 with a flow dividing function having a unique configuration is provided in parallel with the on-off valve 18 with respect to the variable pump 16. This fluid control device 2
2 actively or forcibly supplies hydraulic oil to separate traveling hydraulic motors to drive the associated loads, or increases the pressure of hydraulic oil supplied to the hydraulic motors to reduce these speeds. It is designed to operate at high torque. In the illustrated embodiment, the fluid control device 22 is constituted by hydraulic control units 24 and 26 which can be in fluid communication with the hydraulic motors 12 and 14 respectively during operation and have a predetermined displacement volume. Are FIGS. 3 to 5
The details will be described later with reference to FIG. The displacement volumes or capacities of these hydraulic control units may be different from each other or may be the same. Hydraulic motors 24, 26, 1
The displacement volumes q ₁ , q ₂ , q ₃ ,
q ₄ is capable of various combinations as necessary, vehicle design, it should be noted that can exhibit high flexibility. It is well known to those skilled in the art that the displacement volume of these hydraulic motors has a relation of proportional expression q ₁ : q ₂ ≒ q ₄ : q ₃ . Further, referring to FIG. 1, an electromagnetic switching valve 28 is provided downstream of one of the units 24 constituting the fluid control device 22 in connection therewith. The switching valve 28 can be operated at least between an open position where the hydraulic control unit 24 and the hydraulic motor 12 are in fluid communication, and a drain position where the unit 24 is connected to a low pressure source, that is, the suction side of the variable pump.

The normal differential mode of the vehicle hydraulic drive circuit will be described with reference to FIG. Now, the variable pump 16
Pressure oil in the line 30 discharged from the fluid control device 2
2 flows through the on-off valve 18 which has a lower flow resistance than that of the line 34, passes through it and enters the line 32, the first part of which is connected to the line 34.
To the hydraulic motor 14, where it works and returns to the low pressure side or suction side of the pump 16 which is a low pressure source. On the other hand, the remaining part of the pressure oil passes through the on-off valve 20, which is a flow dividing means, to the hydraulic motor 12 via the line 36, where it works and returns to the low pressure side of the pump 16. Thus, the vehicle can run the front and rear wheels at substantially the same rotational speed.

When a vehicle travels on a slippery road surface such as a rough road having a lot of unevenness, a muddy road or a snowy road, for example, when one of the front and rear wheels slips and loses its driving force, the other also drives the other. Fig. 1 (B)
It is necessary to forcibly distribute the hydraulic oil to the hydraulic motors of the wheels that are not slipping by setting the "differential limit" mode as shown in FIG. Therefore, the driver urges the valves 18 and 20 to the closed position and switches the valve 28 to the open position. Then, the hydraulic oil from the hydraulic pump 16 receives the hydraulic motors 12, 14, 24, 26 because the valve 18 is closed.
Unit 2 of the fluid control device 22 according to a displacement volume ratio (capacity ratio) predetermined by the displacement volume of
4 and 26 in a distributed state. A predetermined amount of hydraulic oil from the unit 26 is supplied via lines 32 and 34 to the hydraulic motor 1.
4 and a predetermined amount of pressure oil that has exited the unit 24 passes through the switching valve 28 and passes through the lines 38 and 36 to the hydraulic motor 12.
Leads to. Since the on-off valve 20 is in the closed position, the unit 2
Note that the hydraulic circuit of the first load including the hydraulic motor 4 and the hydraulic motor 12 and the hydraulic circuit of the second load including the unit 26 and the hydraulic motor 14 are separated from each other. When the above-described four-port two-position valve is used as the flow dividing means, the outlet port of the unit 24 is connected to the hydraulic motor 1
Those skilled in the art will appreciate that the outlet port of the unit 26 can be in communication with the hydraulic motor 12 in communication with the unit 4.

In the differential limiting mode shown in FIG. 1B, the load of the hydraulic motor of the wheel in the slip state is small, and therefore the pressure is low. Requires a high pressure, but the configuration of the present invention can satisfy this requirement for the following reasons. That is, as will be appreciated by those skilled in the art,
Assuming that the outlet pressures of the hydraulic pump 16 and the hydraulic control units 26 and 24 are p ₀ , p ₁ and p ₂ , respectively, the following relational expressions hold.

[0019]

(Equation 1) As can be seen from this equation, if the wheels connected to the hydraulic motor 12 start to slip, the discharge pressure p ₁ of the unit 24 drops, and if the hydraulic motor 14 takes over the load, the discharge pressure of the unit 26 p ₂ is increased (in this case, p ₀ indicates an intermediate value of p ₁ and p _2). Thus, the hydraulic circuit constructed as shown in accordance with the present invention, hydraulic fluid outlet pressure p ₂ of the hydraulic fluid outlet pressure p ₁ and the hydraulic control unit 26 of the hydraulic control unit 24, it is inversely proportional are noted Should be. Therefore,
A pressure higher than the discharge pressure of the variable pump 16 can be obtained on one of the discharge sides of the units 24 and 26 of the fluid control device, and the traction force of the non-slip wheel is increased by the pressure increase effect. Can be done.

The differential / pressure-increasing mode shown in FIG. 1C is preferably used, for example, when the vehicle is running uphill at a low speed and high torque stage on a steep uphill. While maintaining the valve 20 in the open position, the driver urges the on-off valve 18 to the closed position and switches the switching valve 28 to the drain position as shown. Then, the hydraulic oil from the variable pump 16 is distributed to the units 24 and 26 via the line 30 according to these predetermined displacement volume ratios. The pressure oil in the outlet line 32 of the unit 26 is supplied to the hydraulic motors 12, 1
A part is diverted to the hydraulic motor 14 via the line 34 according to the displacement volume ratio of 4, and the remaining part passes through the valve 20,
The hydraulic motor 12 is reached via a line 36. On the other hand, the hydraulic oil that has come out of the unit 24 is directed to the line 40 by the switching valve 28 and is drained to the low pressure side of the hydraulic pump 16. In the differential / pressure intensifying mode, the unit 24
Pressure p ₁ of the discharge oil from the nearly 0, so the following equation holds.

[0021]

(Equation 2) Thus, in the differential and pressure boost mode of the illustrated embodiment, the unit 24 tends to exert a motor action on the unit 26 and tend to rotate it, so that the unit 26 produces a pump action and its operation the oil outlet pressure p ₂ is increased, thus making it possible to drive the vehicle at low speed and high torque stage. When the hydraulic circuit employs a low or light load hydraulic pump,
The pump has the additional advantage of being able to provide medium load pump grade torque or traction.
Further, as will be understood by those skilled in the art, the operation angle of the vehicle speed lever of the variable pump can be made larger than the conventional angle that requires a delicate operation during work such as load transportation. Becomes easier.

Referring to FIG. 2, there is illustratively shown a hydraulic circuit 100 in which the control system of the present invention shown in FIG. 1 is applied to a four-wheel drive force transmission system. In the figure, reference numerals 42, 44
1 correspond to the main parts of the circuit configuration of FIG. 1 and are provided in relation to a pair of left and right wheels of a front wheel, a rear wheel, and a rear wheel, respectively. The components of the hydraulic circuit portions 42 and 44 which are the same as or correspond to the components of FIG. 1 are indicated by the same reference numerals as those of FIG. 1 or with prime symbols. However, the hydraulic circuit portion 44 is not provided with an element corresponding to the electromagnetic switching valve 28 in FIG. This is because, as will be understood by those skilled in the art, in the illustrated four-wheel drive system, the hydraulic circuit portion 44 is configured in a form similar to the circuit of FIG. This causes a speed difference between the front and rear wheels, which hinders traveling. In the figure, reference numeral 46 indicates a relief valve for regulating the charge pressure, and reference numeral 48 indicates a drain tank.

In operation, the hydraulic motors 12a, 12b and 14a, 14b associated with the front wheels and the rear wheels constitute a parallel circuit (center differential state), so that the hydraulic motors 12a, 12b and 14a, When the wheel slips, the hydraulic circuit portion 42 is operated in a procedure similar to that described in connection with FIG. 1 to divert the pressure oil via lines 34 and 36 according to the motor displacement volume ratio of the front and rear wheels. Supply,
The traction of the non-slip wheels can be maintained and increased. Also, as described in connection with FIG. 1C, when working or when a large load is applied to the circuit,
It is preferable to set the hydraulic circuit portion 42 to the differential / pressure-increasing mode to generate a large running torque on the wheels. Next, the operation of the hydraulic circuit portion 44 will be described. In the illustrated example, the hydraulic circuit portion is provided for differential and differential limiting operations of the left and right rear wheels connected to the hydraulic motors 14a and 14b. I have. The hydraulic circuit portion 44 shown in FIG. 2 is equal to the left and right wheels while allowing the left and right driving wheels to rotate differently so that the wheels do not slip on the road surface when the vehicle turns in the differential mode. A predetermined amount of pressure oil is supplied to the hydraulic motors 14a and 14b so as to generate a traction force. Now, when one of the pair of left and right wheels, for example, the left wheel enters the slack and slips and loses the driving force, the operator urges the electromagnetic on-off valves 18 'and 20' to the closed position. To operate the hydraulic circuit portion 44 in the differential limiting mode. Then, according to a predetermined displacement volume ratio of the hydraulic motors 14a, 14b, 24 ', 26', the pressure oil
The hydraulic motor 14b is separately supplied to the hydraulic motor 14b independently of a, thereby rotating the hydraulic motor in accordance with the respective divided flow rates. As a result, the vehicle can escape from the mud.

Referring next to FIG. 3, there is shown a partially cut-away cross-section of a fluid control device 22 with a flow dividing function of the present invention, which is preferably used in a vehicle having at least a pair of traveling hydraulic motors. FIG. 6 is a sectional view taken along line 6-6 in FIG.
FIG. 2 is a cross-sectional view taken along line I-I, showing the scale somewhat enlarged. The fluid control device preferably includes fixedly disposed toothed member moving mechanism type hydraulic control units 24 and 26 having the same configuration on their longitudinal axes 59 in an opposed state, and aligning their respective transmission shafts so as to face each other. They are connected via coupling means 64 so as to rotate integrally. The hydraulic control unit is substantially identical to the configuration of any conventional hydraulic motor having a transmission shaft or an output shaft. In the illustrated embodiment of the present invention, the hydraulic control unit is exemplarily described as having substantially the same structure as the bearingless tooth profile member moving mechanism type hydraulic motor. However, those skilled in the art will appreciate that the principles of the present invention are equally applicable to any other hydraulic motor with a transmission shaft or output shaft, such as a gear motor, vane pump, or the like.

FIG. 4 is a sectional view of one of the units 24 constituting the fluid control device 22. The basic configuration of such a unit is substantially the same as that of a tooth-shaped member moving mechanism type hydraulic motor widely used for turning or traveling of various construction machines, for example, a hydraulic shovel. Since it is well known to those skilled in the art (see, for example, Japanese Patent Publication No. 56-19478), it is schematically described below. As best seen in FIG.
The hydraulic control unit 24 typically comprises a first toothed member or girola ring 64 with internal teeth, a plurality of externally toothed members provided in the first toothed member for planetary movement relative to the first toothed member. It has a second tooth profile member or giroller star 66 and a giroller mechanism 50 having a plurality of volume chambers 68 formed between the inner teeth of the giroller ring 64 and the outer teeth of the giroller star 66 (5- in FIG. 4). FIG. 5 which is a sectional view taken along line 5
See also). A valve housing 72 having an inlet port 74 and an outlet port 76 is adjacent to and fixed to the toothed member moving mechanism or the di-roller mechanism via a valve plate 70. In the valve housing, the hydraulic oil from the hydraulic pump is introduced into the volume chamber 68 through the inlet port 74 and the hydraulic oil in the volume chamber is introduced into the outlet port 76.
A valve arrangement 78 including a rotatable valve element 80 operable to direct the valve arrangement is provided. As shown, the main drive or transmission shaft 58 is splined at one end 61 to a girler star 66 with a slight inclination with respect to the longitudinal axis 59 of the hydraulic motor to take out its rotational movement. ing.

In the illustrated hydraulic motor configuration example, as is known to those skilled in the art, the valve element 80 of the valve device 78
One end is splined to the rotatable roller star 66 and the other end is splined to the recess in the rotary valve element 80, and passes through a central hole in the valve plate 70 and also slightly with respect to the longitudinal axis 59 of the hydraulic motor. The valve shaft 81 is provided in an inclined state. Valve shaft 8
One purpose is to provide a transmission shaft 58 as is well known to those skilled in the art.
The purpose of the present invention is to maintain appropriate valve timing by compensating for abrasion of the spline connection between the spline joint 66 and the girler star 66.

Still referring to FIG.
4 further comprises a flange plate 52 fixedly provided on the opposite side of the valve housing 72 and adjacent to the tooth member moving mechanism 62 and having a central through hole 56 and a peripheral mounting lug or projection 54. I have. The through holes in the flange plate are preferably counterbored from one side. A transmission shaft 58 extends outside through the through hole 56.

Referring again to FIGS. 3 and 6, the fluid control device 22 with a flow dividing function according to the present invention has a hollow casing 50 having an arbitrary shape, and the opposite end surfaces 51 and 51 'are provided with a unit 24. , 26 flange plates 52, 5
2 'are respectively hermetically mounted by fixing means, for example bolts 55, 55'. As shown in the figure, in the hollow portion of the casing 50, the transmission shaft 58 is rotatable in the axial direction by sleeve bearings 57, 57 ′ provided at both ends in counter bores of through holes 56 of the flange plate of the hydraulic control unit. , 58 'is provided with a coupling member 64, preferably a hollow cylindrical sleeve shaft, supported substantially concentrically with the shaft member. A chamber or space 53 is defined between the inner surface of the casing and the outer surface of the coupling member, the space being defined by the active hydraulic control unit 2.
The hydraulic fluid leaking from the volume chamber 68 in the high-pressure state of the tooth profile member moving mechanisms 4 and 26 is filled with hydraulic oil. The sleeve shaft 64 is connected to the hydraulic control unit 24,
Both ends are open to receive the 26 transmission shafts 58, 58 '. An inner spline 65 is provided in the inner peripheral portion of the sleeve shaft 64 in the axial direction. The inner spline 65 is engaged with the outer splined outer ends 60 and 60 ′ of the transmission shaft, and is the same as the sleeve shaft 64. It rotates in the direction. Reference numerals 65 and 65 'denote O-rings provided between the inner surfaces of the through holes 56 and 56' of the flange plate and each end of the sleeve shaft 64 to seal them.

As shown, preferably within the hollow portion of the cylindrical sleeve shaft 64, between the outer ends 60, 60 'of the opposed transmission shafts to keep them apart during operation. As best seen in FIG. 6, a spacer 67 is provided, preferably in the form of a disc with a central through-hole 83. The sleeve shaft 64 preferably has at least two through holes 69 around its cylindrical wall. Advantageously, the hydraulic oil in the space 53 passes through the transverse through hole 69 of the sleeve shaft, passes through the flaline groove, to the connection between the inner spline portion on the inner periphery of the sleeve shaft and the outer spline outer end of the transmission shaft, This is cooled and depleted. Hydraulic oil is drained from the hydraulic control unit to a low pressure source through a drain hole 82 provided through the flange plate of the unit shown in FIG.

In the fluid control device 22 with the flow dividing mechanism configured as described above, the hydraulic oil port 7 of the units 24 and 26
4, 74 'are hydraulic oil inlets communicating with the discharge side of the hydraulic pump 16, and ports 76, 76' are hydraulic oil branch outlets.
Since the transmission shafts 58, 58 'of the units 24, 26 are connected so as to rotate integrally by the sleeve shaft 64 as described above, the hydraulic oil flowing into the ports 74, 74' respectively corresponds to FIG. Are forced from the branch outlet ports 76, 76 'to the associated hydraulic motors 12, 14 at a flow rate determined by the predetermined displacement volume ratio described in connection with the differential limiting mode.
If the transmission shafts do not rotate integrally and the hydraulic control units 24, 26 operate independently, all high pressure hydraulic fluid from the variable pump 16 is directed to the lower pressure hydraulic control unit. Therefore, the other hydraulic control unit does not operate, and as a result, the vehicle cannot travel. In the differential / pressure-increasing mode of FIG. 1C, as described above, the hydraulic control unit having the lower load associated with the outlet ports 76 and 76 ', in other words, the hydraulic pressure control unit having the lower outlet pressure operates the motor. The unit on the high load side or the high outlet pressure side exerts a pump action, and thus a pressure increasing effect is obtained. Since the flow of hydraulic oil in each hydraulic control unit is well known to those skilled in the art, a detailed description is not considered necessary. If necessary, for example, the above-mentioned JP-B-56-1
See No. 9478.

[0031]

[Brief description of the drawings]

FIG. 1 is a diagram showing a hydraulic drive control circuit for a vehicle embodying the principle of the present invention in various operation modes;
(B) and (C) show the hydraulic circuit and its components in a differential mode, a differential limiting mode, and a differential / pressure-increasing mode, respectively.

FIG. 2 is a diagram when the control system of the present invention is applied to a four-wheel drive force transmission system.

FIG. 3 is a partially cutaway side view of the fluid control device with a flow dividing function of the present invention.

FIG. 4 is a sectional view of one hydraulic control unit constituting the fluid control device of the present invention.

FIG. 5 is a view taken in the direction of arrows 5-5 in FIG. 4;

FIG. 6 is an enlarged sectional view taken along line 6-6 of FIG. 3;

[Explanation of symbols]

12, 14 Traveling hydraulic motor 16 Variable pump 18, 20, 28 Solenoid valve 22 Fluid control device 24, 26 Tooth profile member moving mechanism type hydraulic control unit 50 Casing 52 Flange plate 58 Transmission shaft 62 Tooth profile member moving mechanism Tusset) 64 Sleeve shaft 67 Spacer 69 Hydraulic oil flow hole 72 Valve housing 78 Valve device

Claims (15)

[Claims] 1. A drive control system for a vehicle having a traveling hydraulic motor, comprising: a variable displacement hydraulic pump; a first hydraulic motor operatively connected to a first load of the vehicle; A second hydraulic motor operatively connected to the second load, a normal open position capable of guiding a flow of hydraulic oil from the hydraulic pump to the first and second hydraulic motors, and a closing position for shutting off the open position; A first valve operable between the first position and the second position;
Means, located downstream of the first valve, for passively diverting the flow of hydraulic oil from the hydraulic pump to the first and second hydraulic motors, provided in parallel with the first valve; A fluid control device having a flow dividing function for receiving hydraulic oil from the hydraulic pump when the first valve is in the closed position, wherein the fluid control device includes a first hydraulic motor and a second hydraulic motor. And in fluid communication with one of the first hydraulic control unit and the other of the first and second hydraulic motors having a first displacement volume and a first hydraulic oil outlet pressure, The first hydraulic control unit and the second hydraulic control unit each have a second displacement volume and a second hydraulic oil outlet pressure, and the first hydraulic control unit and the second hydraulic control unit control the flow of hydraulic oil from the hydraulic pump to the second hydraulic control unit. Displacement volume of first and second hydraulic control units Operatively associated with each other to be distributed to the first and second hydraulic control units, respectively, in a normal differential mode, wherein the first valve is in the open position and the hydraulic oil from the hydraulic pump is Flow through the first hydraulic motor and the second hydraulic motor through the first valve.
When the traction force of one of the first and second loads is reduced, the first valve is operated to the closed position to switch from the differential mode to the differential limiting mode, The flow of hydraulic oil from the pump is distributed to the first and second hydraulic control units of the fluid control device according to their displacement volume ratios, and via the first and second hydraulic control units, the associated hydraulic motor And the first hydraulic oil outlet pressure of the first hydraulic control unit is inversely proportional to the second hydraulic oil outlet pressure of the second hydraulic control unit. Characteristic control system. 2. In the differential mode, the passive flow dividing means takes a normal open position in which the flow of hydraulic oil from the first valve is flowed to the first hydraulic motor and the second hydraulic motor, and A hydraulic fluid flow portion from the first hydraulic control unit of the fluid control device to the first hydraulic motor in the motion restriction mode;
2. The control system according to claim 1, wherein the control system is an electromagnetic on-off valve that is operated to a closed position that isolates a portion of the hydraulic oil flow from the second hydraulic control unit to the second hydraulic motor. 3. The passive flow dividing means takes a normal operating position in a differential mode, in which a flow of hydraulic oil from a first valve is divided into a first hydraulic motor and a second hydraulic motor. An associated hydraulic motor that is operated in an operating position to communicate the first hydraulic control unit and the second hydraulic motor of the fluid control device and to communicate the second hydraulic control unit to the first hydraulic motor in the motion restriction mode An electromagnetic switching valve operable between a closed position that isolates a hydraulic fluid flow portion from the second hydraulic control unit to a hydraulic fluid flow portion from the second hydraulic control unit to an associated hydraulic motor. The control system according to claim 1, wherein: 4. A hydraulic motor which is provided in series with the hydraulic control unit downstream of one of the first and second hydraulic control units of the fluid control device, the one hydraulic control unit and a hydraulic motor associated therewith. Opening position for fluid communication,
A switching valve that allows the one hydraulic control unit to communicate with a low pressure source and that can be operated between a drain position where the outlet pressure of the other hydraulic control unit is increased, and a first valve in the differential / pressure increasing mode. The valve is operated to the closed position and the switching valve is operated to the drain position, and the flow of the hydraulic oil from the hydraulic pump is distributed to the first and second hydraulic control units of the fluid control device according to the displacement volume ratio. And
The hydraulic oil flow portion distributed to the one hydraulic control unit is drained to a low pressure source through a switching valve, and the hydraulic oil flow portion distributed to the other hydraulic control unit is increased in pressure,
2. The control system according to claim 1, wherein said passive shunting means shunts the first and second hydraulic motors. 5. The passive hydraulic diversion means, according to claim 1, further comprising a first hydraulic motor and a second hydraulic motor which, in a differential / pressure-increasing mode, distribute a hydraulic oil flow portion distributed to the other hydraulic control unit whose pressure has been increased. 5. The control system according to claim 4, wherein the control system is located at an open position where the flow is diverted. 6. The control system according to claim 1, wherein the first valve is an electromagnetic on-off valve. 7. The first and second loads are a pair of front wheels and a pair of rear wheels of the vehicle, and one of the first and second hydraulic motors is operatively connected to the pair of front wheels of the vehicle, respectively. The first and second hydraulic motors are operatively connected to a pair of rear wheels of the vehicle, respectively, and are hydraulically connected to each other. 7. The control system according to claim 1, comprising two hydraulic motors connected in parallel to the control system. 8. The vehicle according to claim 1, wherein the first load is one of a left side and a right side of the pair of front wheels of the vehicle, and the second load is a side of the left side or the right side of the pair of front wheels of the vehicle. The control system according to claim 1. 9. The first load is one of the left or right side of a pair of rear wheels of the vehicle, and the second load is the other of the left or right side of a pair of rear wheels of the vehicle. The control system according to any one of claims 1 to 6, wherein 10. A fluid control device for use in a vehicle having at least a pair of traveling hydraulic motors, the hydraulic control device being capable of shunting hydraulic oil to each traveling hydraulic motor, wherein the first and second sides are opposite to each other. Hollow casings each having an end face, each of which is hermetically and securely attached to the first and second end faces of the casing, respectively, and extends outwardly through the flange plate having the through hole and the through hole. And two hydraulic control units including a rotatable transmission shaft in opposing alignment and located in the casing;
Both ends are supported rotatably with respect to the flange plate of the hydraulic control unit and substantially concentrically with the transmission shaft and are firmly connected to the outer ends of the two transmission shafts, and are integrated with the two transmission shafts. A fluid control device, comprising: a coupling member that is adapted to rotate. 11. The hydraulic control unit of the fluid control device, wherein each of the hydraulic control units has a first tooth member having internal teeth, and a plurality of external teeth provided in the first tooth member so as to be planetary with respect to the first tooth member. A second tooth profile member, a tooth profile member moving mechanism portion having a plurality of volume chambers formed between the internal teeth and the external teeth, and a valve member adjacent to and adjacent to the tooth profile member moving mechanism portion via a valve plate. A valve housing fixed and provided with an inlet port and an outlet port; and a hydraulic oil from the hydraulic pump housed in the valve housing and introduced into or operated in the volume chamber through the inlet port. A valve arrangement including a rotatable valve element operable to direct oil to an outlet port, wherein the inner end of the transmission shaft is splined to a splined bore of the second tooth member;
The flange plate is disposed adjacent to the tooth member moving mechanism on the side opposite to the valve plate and fixed to the valve housing, and the inlet port of the valve housing of each hydraulic control unit is connected to the discharge side of the hydraulic pump. The first and second hydraulic control units can be in fluid communication, one outlet port of the first and second hydraulic control units is connected to one of the first and second hydraulic motors, and the other outlet port of the first and second hydraulic control units is The fluid can be in fluid communication with the other of the first and second hydraulic motors, respectively.
Into the inlet port of the hydraulic control unit, distributed in accordance with the displacement volume ratio determined by the volume chamber, flowed in, and diverted to the associated hydraulic motors through the respective outlet ports of the respective hydraulic control units. The fluid control device according to claim 10, wherein: 12. The coupling member is a hollow cylindrical sleeve shaft having both ends opened to receive the outer ends of the transmission shafts of the first and second hydraulic control units, and the sleeve shaft has an inner peripheral portion thereof. The fluid control device according to claim 10, wherein the fluid control device is fixed to an outer end of the transmission shaft by a connecting means. 13. The connecting means comprises an inner spline portion provided on an inner peripheral portion of the sleeve shaft, and an outer spline portion provided on an outer end portion of the transmission shaft connected thereto. The fluid control device according to claim 12. 14. The sleeve shaft has at least two lateral through holes in a part of its cylindrical wall, and a low pressure space is defined between the sleeve shaft and a casing surrounding the sleeve shaft. The hydraulic fluid leaks and fills the spline connection between the inner periphery of the sleeve shaft and the outer end of the transmission shaft through the lateral through hole of the sleeve shaft, cools and depletes it. The fluid control device according to claim 12 or 13, wherein 15. A spacer is provided in the hollow portion of the sleeve shaft between the outer ends of the transmission shafts of the first and second hydraulic control units opposed to each other. A fluid control device according to any one of the preceding claims.