JPH10169774A - Fluid driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the run-away of a vehicle by mounting a self-contained valve to resupply operating oil leaked from a motor or an oil pump to main pipe passages for a closed circuit, even if the motor for the vehicle is stopped on a slope or the vehicle is moved down on the slope with a self-weight, a wheel is rotated and a hydraulic motor is rotated via the wheels for pumping operation. SOLUTION: A fluid driver has a main pump 1 and a charge pump 2 driven by a motor, a hydraulic motor 3 connected from the main pump to a closed circuit formed with main pipe passages, check valves 7a, 7b mounted on a charge passage communicated between the main pipe passages to supply operating oil from the charge pump to the main pipe passages, a low pressure relief valve 6 provided in the charge passage to escape charge pressure into a case 13, a high pressure relief valve 8 to restrict high pressure in the main pipe passages, neutral valves 9a, 9b to escape operating oil into the case in small pressure areas in the main pipe passages and an unload valve 10 connected between the main pipe passages to unload high pressure in the main pipe passages into low pressure. A self-contained valve 17 is mounted thereon to allow only the flow of operating oil from the case 13 to the charge passage 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to prevention of runaway of a vehicle on a slope when a prime mover (engine) of the vehicle is stopped.
In particular, the present invention relates to improvement of a circuit configuration in a fluid drive device (HST).

[0002]

2. Description of the Related Art For example, conventionally, as shown in FIG. 5, a fluid drive device of this type includes a variable displacement pump 1 and a charge pump 2 driven by a motor (not shown), a variable displacement pump 1 and a hydraulic pump. A closed circuit 4 formed by connecting the motor 3 with the main lines 5a and 5b, and a main line 5a from the charge pump 2 between the main lines 5a and 5b on both sides of the hydraulic motor 3 of the closed circuit 4. And two check valves 7a and 7b connected to supply hydraulic pressure set by the low-pressure relief valve 6 to compensate for leakage of the main line 5a and 5b, and a dual-effect high-pressure relief that regulates the pressure of the main pipelines 5a and 5b. A valve 8 and two neutral valves 9 for releasing hydraulic oil when there is almost no discharge pressure so as to stop the rotation of the hydraulic motor 3 in a minute range of the discharge pressure of the variable displacement pump 1.
a, 9b and the main pipeline 5a which are communicated between the main pipelines 5a and 5b.
Unload valve 1 for unloading high pressures a and 5b to low pressure
The hydraulic motor 3 rotates according to the discharge oil of the variable displacement pump 1 driven by the prime mover to drive the wheels (not shown) and to discharge the hydraulic oil from the charge pump 2. To the charge passage 11 and the check valve 7a.
7b, the hydraulic oil leaked from the variable displacement pump 1, the hydraulic motor 3 and the like is replenished.
Hydraulic oil flowing into the case 13 via the low-pressure relief valve 6 and remaining in the case 13 is drained from the drain port D to the tank T.
To return to

[0003]

In the above-described structure of the conventional fluid driving device, when the vehicle stops the engine on the slope, the vehicle gradually descends on the slope by its own weight, and when the wheels of the vehicle rotate. , Hydraulic motor via wheels
The rotation of the motor acts as a pump, but the supply of hydraulic oil from the charge pump has stopped, and the piston, cylinder block, and valve press of the hydraulic motor and variable displacement pump have been stopped.
The structure is such that hydraulic oil that has leaked from between the ports cannot be supplied to the closed circuit.If hydraulic oil is not supplied to the closed circuit, air enters the main line of the closed circuit and air When the hydraulic motor in the hydraulic motor almost loses its hydraulic fluid, the hydraulic motor runs idle as if it were in a no-load condition. There was a problem that they could run away.

[0004] Therefore, the present invention provides a hydraulic motor for driving a vehicle down a hill by its own weight even if the vehicle stops an engine on the hill.
Even if the motor rotates and performs a pumping operation, a self-supply valve for supplying hydraulic oil leaked from a hydraulic motor or a pump to the main line of the closed circuit is interposed to prevent the vehicle from running away. It is to provide a fluid drive device that can be used.

[0005]

According to a first aspect of the present invention, a main pump and a charge pump driven by a prime mover are provided.
A hydraulic motor connected to a closed circuit formed by the main line from the main pump, and a check interposed between the main lines in a charge passage communicating with the supply oil from the charge pump to the main line. Charge pressure from valve and charge passage
A low-pressure relief valve that releases into the casing, a dual-effect high-pressure relief valve that regulates high pressure in the main pipeline, a neutral valve that allows hydraulic oil to escape into the case in a minute range of the main pipeline pressure, and a main pipe. A self-sufficient valve for allowing only the flow of hydraulic oil from within the case to the charge passage, comprising an unload valve connected between the passages for unloading the high pressure of the main line to a low pressure. Intervene.

According to a second aspect of the present invention, in the first aspect, the self-sufficient valve has a small-diameter step formed in a passage penetrating a poppet of the low-pressure relief valve, and a passage inserted into the small-diameter step to form a passage. The valve includes a valve that shuts off the communication and a regulating member that intersects and locks the passage so as to regulate the movement of the valve.

According to a third aspect of the present invention, a main pump and a charge pump driven by a prime mover, a hydraulic motor connected to a closed circuit formed by a main pump from the main pump, and a charge pump provided between the main pumps are provided. A check valve interposed in a charge passage communicating with the main line to supply hydraulic oil, a low-pressure relief valve provided in the charge passage to release a charge pressure into the case, and a main pipe. A dual-effect high-pressure relief valve that regulates high pressure in the passage, a neutral valve that allows hydraulic oil to escape into the case in a minute region of the main passage pressure, and a high pressure in the main passage that is connected between the main passages and that has a low pressure. In a fluid drive device comprising an unloading valve for unloading, a self-supply valve for allowing only a flow of hydraulic oil from inside the case to the main pipeline is interposed.

According to a fourth aspect of the present invention, in the third aspect, the self-supplying valve is formed with a stepped portion formed so as to communicate with a main conduit provided in the port block and the inside of the case, and is engaged with the stepped portion. A plug, a small-diameter step formed in a passage passing through the plug, a valve fitted into the small-diameter step to shut off communication with the passage, and a restricting member intersecting and locking the passage so as to restrict the movement of the valve. Consists of

According to a fifth aspect, in the second and fourth aspects, the valve comprises a steel ball.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The first embodiment shown in FIG. 1 is different from the above-mentioned conventional fluid drive device only in the configuration in which a self-supply valve for allowing the flow of hydraulic oil from inside the case to the charge passage is interposed. Others are the same as the conventional example,
Therefore, only different configurations will be described, other components will be omitted, and the same components will be denoted by the same reference numerals.

Therefore, the first embodiment is provided such that the variable displacement pump 1 and the charge pump 2 are driven by a prime mover (not shown).

A closed circuit 4 is formed in which the variable displacement pump 1 (hereinafter referred to as a main pump) is connected to the hydraulic motor 3 by main lines 5a and 5b.

The main line 5 is connected between the main lines 5a and 5b of the closed circuit 4 from the charge pump 2 via the charge passage 11.
Two check valves 7a and 7b that operate so as to compensate for the shortage of hydraulic oil at a and 5b are connected.

In order to keep the pressure in the charge passage 11 constant, a low-pressure relief valve 6 for releasing excess oil from the charge passage 11 into the case 13 is interposed.

As shown in FIG. 2A, the low pressure relief 6 is provided with a poppet 15 urged by a spring member 16 into a hole 14a facing the charge passage 11 provided in the port block 14.
When the pressure in the charge passage 11 exceeds the set pressure, the poppet 15 opens, and the port block 14 and the case
The surplus oil is allowed to escape into the case inner chamber 13a formed by the casing 13 and the casing 13.

A self-supply valve 17 which allows only the flow of hydraulic oil from the case inner chamber 13a to the charge passage 11 in the charge passage 11 is interposed in the poppet 15 of the low-pressure relief valve 6. is there.

As shown in FIG. 2B, the self-supplying valve 17 is connected to the poppet 15 of the low-pressure relief valve 6 in the case inner chamber 1.
A passage hole 18 communicating the charge passage 3a and the charge passage 11 is formed, and a small-diameter step portion 19 is formed in the passage hole 18.

A steel ball 20 is mounted on the small-diameter step 19 so as to shut off the passage 18.

Further, the steel ball 20 is provided with the small-diameter step portion 1.
A hole 2 provided so that a pin 21 as a regulating member intersects the passage 18 so as to regulate the movement so as not to jump out of the passage 9.
2 is press-fitted.

The self-supply valve 17 is connected to the charge passage 11.
Only when the pressure Pc becomes lower than the pressure Pd of the case inner chamber 13a (Pc <Pd), the operating oil flows from the case inner chamber 13a to the charge passage 11, and the check valve 7a or 7b is operated. Hydraulic oil is supplied to the main pipeline 5a or 5b via the main line.

Next, the operation will be described. Now, if a vehicle (not shown) stops the engine on a slope, the vehicle tries to go down the slope by its own weight, and power is transmitted to the hydraulic motor 3 of the fluid drive device via wheels, and the hydraulic motor is driven. The pump 3 acts as a pump to rotate, and the pressure Pa in one main line 5a or the pressure Pb in the other main line 5b rises.

When the pressure Pa in one main line 5a increases, hydraulic oil leaks from the hydraulic motor 3, the main pump 1, etc., and the leaked hydraulic oil flows into the case inner chamber 13a, and the main line Hydraulic motor 3
Rotates and supplies hydraulic oil from the other main line 5b.

However, since the engine of the vehicle is stopped, the main pump 1 does not rotate, and the charge pump 2 is also stopped, so that there is no supply of hydraulic oil from the charge pump 2 and the other end. The working oil in the main pipeline 5b gradually decreases.

When the hydraulic oil in the main line 5b gradually decreases and the pressure Pb in the main line 5b becomes lower than the pressure Pc in the charge passage 11 (Pb <Pc), the check valve 7b opens.

Further, the pressure Pc of the charge passage 11 becomes lower than the pressure Pd of the case inner chamber 13a (Pc <P).
d), due to the pressure difference (Pd-Pc), the steel ball 20 of the self-supply valve 17 moves rightward in the figure, and the case inner chamber 13a
Flows through the passage hole 18, the charge passage 11, and the check valve 7b to the other main pipe line 5b.

The operating oil flows to the other main line 5b through the passage hole 18, the charge passage 11, and the check valve 7b, and the operating oil in the one main line 7a leaks from the hydraulic motor 3. Then, it flows into the case inner chamber 13a and is circulated.

For this reason, the hydraulic motor 3 is always replenished with hydraulic oil even if it rotates, and the air rail due to insufficient hydraulic oil is supplied.
And no hydraulic motor 3
Does not run idle and can prevent the vehicle from running away.

As described above, the charge from the case inner chamber 13a is performed.
Since the self-supply valve 17 that allows only the flow of hydraulic oil to the passage 11 is interposed, the vehicle is driven on a slope by an engine.
Even if the vehicle stops, the vehicle goes down the slope by its own weight, the wheels of the vehicle rotate, and the hydraulic motor 3 rotates via the wheels to perform a pumping operation. 1
The hydraulic oil leaked from the main circuit 5a or 5
b, the hydraulic oil is not replenished in the closed circuit 4 and the hydraulic oil in the hydraulic motor 3 does not escape, and air is mixed in the main line 5a or 5b of the closed circuit 4. As a result, no aeration occurs, so that the hydraulic motor 3 does not run idle as in the no-load state, and the vehicle can be prevented from running off the slope.

Since the self-supply valve 17 is interposed in the poppet 15 of the low-pressure relief valve 6, the self-supply valve 17 and the low-pressure relief valve 6 are combined, so that it is not necessary to newly install the self-supply valve 17. Therefore, the number of parts can be reduced, the cost can be reduced, and the size can be reduced.

Next, the second embodiment shown in FIG. 3 is similar to the first embodiment only in the configuration in which a self-supply valve for permitting the flow of oil from inside the case to the main pipeline is interposed. This is different from the conventional example, and the others are the same as the conventional example. Therefore, only the different configuration will be described, other components will be omitted, and the same components will be denoted by the same reference numerals. It is.

In the second embodiment, the main conduits 5a and 5b forming the closed conduit 4 are connected to the main conduits 5a and 5a from the case inner chamber 13a.
Self-supply valves 25a and 25b that allow only the oil flow to 5b are interposed.

The self-sufficient valves 25a and 25b are shown in FIG.
As shown in (b), the main pipes 5a and 5b provided in the port block 14 are fitted into a step diameter portion 26 formed so as to communicate with the case inner chamber 13a.

A screw portion 27 is formed on the step diameter portion 26, and a plug 28 is screwed into the screw portion 27 and locked.

A passage hole 29 is provided through the plug 28, and a small-diameter stepped portion 30 is formed in the passage 29.

A steel ball 31, which is a valve, is mounted on the small-diameter stepped portion 30 so as to shut off the passage 29.

Then, the steel ball 31 is a small-diameter stepped portion 3.
A pin 33 as a restricting member is press-fitted into a hole 32 provided to cross the passage 29 so as to restrict the movement of the steel ball 31 so as not to protrude from zero.

When the pressure Pa of the one main pipe line 5a becomes lower than the pressure Pd of the case inner chamber 13a (Pa <P
d), due to the differential pressure (Pd-Pa), the steel ball 31 of the self-supply valve 25a moves downward in the figure, and the case inner chamber 13
The hydraulic oil a flows into the main pipeline 5a via the passage 29, and can supply the shortage of the hydraulic oil in the main pipeline 5a.

The same applies to the case where the pressure Pb of the other main line 5b becomes lower than the pressure Pd of the case inner chamber 13a.

As described above, the port block 14 is provided with the self-supply valves 25a and 25b that allow only the flow of hydraulic oil from the case inner chamber 13a to the main pipelines 5a and 5b.
As in the first embodiment, even if the vehicle stops the engine on the slope, the vehicle goes down the slope by its own weight, the wheels of the vehicle rotate, and the hydraulic motor 3 rotates via the wheels. Even if the pump works, the hydraulic oil leaked from the hydraulic motor 3 or the main pump 1 and the like is removed from the main line 5a of the closed circuit 4,
5b, the hydraulic oil is not replenished to the closed circuit 4, the hydraulic oil in the hydraulic motor 4 does not escape, and the air is mixed into the main pipelines 5a, 5b and the air rate is also reduced. Since no oil is generated, the hydraulic motor 3 becomes the same as in the no-load state and does not run idle, so that the vehicle can be prevented from running off the slope and the self-supply valves 25a and 25b are closed.
The pipes and the main pipes 5a and 5b are individually connected to the main pipes 5a and 5b on the block 14, and can be installed at any position on the main pipes 5a and 5b. It is not affected and the degree of freedom in design is increased.

[0040]

According to the first aspect of the present invention, a self-sufficient valve that allows only the flow of hydraulic oil from inside the case to the charge passage is interposed, so that the vehicle can operate the engine on a slope. Even when the vehicle is stopped, even if the vehicle descends on a slope due to its own weight, the wheels of the vehicle rotate, and the hydraulic motor rotates via the wheels to perform a pumping operation, the hydraulic motor or the main pump or the like does not stop the vehicle. Since the leaked hydraulic oil can be supplied to the closed circuit main line, the state in which the hydraulic oil is not replenished in the closed circuit disappears, the hydraulic oil in the hydraulic motor does not fall out, and the closed circuit main line is not released. As a result, the hydraulic motor does not run idle because the air does not mix with the air, and the hydraulic motor does not run idle, and the vehicle can be prevented from running off the slope.

According to a second aspect of the present invention, in the first aspect, the self-contained valve has a small-diameter step formed in a hole passing through a poppet of the low-pressure relief valve, and is fitted and inserted into the small-diameter step. Since the low-pressure relief valve poppet is provided with a valve for communicating and blocking the passage and a regulating member that intersects the passage so as to regulate the movement of the valve, the self-supply valve and the low-pressure relief valve are interposed. By combining the relief valve, there is no need to newly install a self-sufficient valve, the number of parts can be reduced, the cost can be reduced, and the size can be reduced.

According to the third aspect of the present invention, a self-supply valve that allows only the flow of hydraulic oil from inside the case to the main pipeline is interposed. Even when the prime mover (engine) is stopped, the vehicle goes down the slope by its own weight, the wheels of the vehicle rotate, and the hydraulic motor is driven through the wheels.
Even if the motor rotates and pumps, the hydraulic oil leaked from the hydraulic motor or the main pump can be supplied to the main circuit of the closed circuit, so that the state where the hydraulic oil is not supplied to the closed circuit is eliminated. Since the hydraulic oil in the hydraulic motor does not escape and air does not enter the main circuit of the closed circuit and air pulsation does not occur, the hydraulic motor rotates in the same way as in the no-load state and runs idle. Therefore, the vehicle can be prevented from running off the slope.

According to a fourth aspect, in the third aspect, the self-sufficient valve is connected to a main line provided in a port block by a cable.
The step diameter part formed so as to communicate with the inner chamber, the plug engaged with the step diameter part, the small diameter step part formed in the passage penetrating the plug, and the passage that is inserted into the small diameter step part to interrupt the communication with the passage And a regulating member that intersects and locks the passage so as to regulate the movement of the valve. It can be installed at any position on the main pipeline, and is not affected by the oil level of the working oil in the piping or case, so that the degree of freedom in design is increased.

According to the fifth aspect of the present invention, since the valve is formed of a steel ball, it is easily available and inexpensive.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a fluid drive device showing an embodiment of the present invention.

FIG. 2A is a longitudinal sectional view of the fluid drive device. (B) It is an expanded sectional view of the A section.

FIG. 3 is a hydraulic circuit diagram of a fluid drive device according to another embodiment.

FIG. 4A is a front view of a port block in the fluid drive device. FIG. 3B is a sectional view taken along line YY.

FIG. 5 is a hydraulic circuit diagram of a fluid drive device showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main pump 2 Charge pump 3 Hydraulic motor 4 Closed circuit 5a, 5b Main line 6 Low pressure relief valve 7a, 7b Check valve 8 Double-sided relief valve 9a, 9b Neutral valve 10 Unload valve DESCRIPTION OF SYMBOLS 11 Charge passage 13 Case 13a Case inner chamber 14 Port block 15 Poppet 16 Spring 17 Self-supplying valve 18 Passage hole 19 Small diameter step 20 Steel ball 21 Pin 22 Hole 25a, 25b Self-supply valve 26 step Diameter part 27 Screw part 28 Plug 29 Passage hole 30 Small diameter step part 31 Steel ball 32 hole 33 Pin Pa Pressure of main line 5a Pb Pressure of main line 5b Pc Pressure of charge passage Pd Case inner chamber Pressure D Drain port T Tank

Claims (5)

[Claims] A main pump and a charge pump driven by a prime mover, a hydraulic motor connected to a closed circuit formed by a main line from the main pump, and a charge pump between the main lines.
A check valve interposed in a charge passage communicating the hydraulic pump from the charge pump to the main line, a low-pressure relief valve for releasing charge pressure from the charge passage into the case, and a main line. A dual-effect high-pressure relief valve that regulates high pressure in the passage, a neutral valve that allows hydraulic oil to escape into the case in a minute region of the main passage pressure, and a high pressure in the main passage that is connected between the main passages and that has a low pressure. Unro
A self-sufficient valve that allows only the flow of hydraulic oil from inside the case to the charge passage. 2. The self-contained valve includes a small-diameter step formed in a hole penetrating a poppet of the low-pressure relief valve, a valve inserted into the small-diameter step to communicate and shut off a passage, and controls movement of the valve. 2. The fluid drive device according to claim 1, wherein the fluid drive device comprises a regulating member intersecting and locking the passage so as to regulate. 3. A main pump and a charge pump driven by a prime mover, a hydraulic motor connected to a closed circuit formed by a main line from the main pump, and a charge pump to a main line between the main lines. A check valve interposed in a charge passage communicating with supply of hydraulic oil, a low-pressure relief valve connected so as to release a charge pressure from the charge passage into the case, and a main pipe High-pressure high-voltage relay that regulates high-pressure roads
And a neutral valve for releasing hydraulic oil into the case in a minute region of the main line pressure, and an unload valve connected between the main lines to unload the high pressure of the main line to a low pressure. A self-sufficient valve that allows only the flow of hydraulic oil from inside the case to the main pipeline. 4. A self-sufficient valve comprising: a stepped portion formed so as to communicate a main conduit provided in a port block with a case; a plug engaged with the stepped portion; and a passage passing through the plug. A small-diameter step formed into a small-diameter step, a valve fitted into the small-diameter step and mounted so as to block communication with the passage, and a restricting member intersecting and locking the passage so as to restrict the movement of the valve. The fluid drive device according to claim 3, wherein: 5. The fluid driving device according to claim 2, wherein said valve is made of a steel ball.