JPH059526Y2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention relates to a diversion valve that divides working oil into a plurality of fluid pipes in a fluid circuit.

(Prior Art) Generally, for example, in a fluid circuit of an industrial vehicle, working fluid from a fluid source is divided into fluid pipes of a cargo handling system where fluid pressure fluctuates widely and a steering system where fluid pressure is required to be constant. to do so,
A configuration is adopted in which a diversion valve is installed at the branch point to divide the required amount of working fluid into each pipe. This diverter valve consists of one inlet port communicating with a fluid source and a pair of discharge ports communicating with both the cargo handling system and the steering system fluid pipes, and is used to operate the steering operation member and the cargo handling operation member. Therefore, the relief pressures of the corresponding fluid pipes are changed, and the working fluid entering from the inflow port is led out to the fluid pipes to perform cargo handling and steering operations.

FIG. 4 shows a diverter valve installed in the hydraulic circuit of an industrial vehicle. That is, a spool 51 is movably disposed in a valve chamber 50a formed inside the housing 50, with the right side of the spool 51 serving as a first damper chamber 52 and the left side serving as a second damper chamber 54. This spool 51 is urged toward the second damper chamber 54 by a push spring 53 provided in the first damper chamber 52, and in the figure, the spool 51 is connected to a steering discharge port (hereinafter referred to as a spooling port) 55. is opened, and the cargo handling discharge port (hereinafter referred to as cargo handling port) 55a is closed.

When the engine starts, the working oil flowing from the hydraulic source into the inflow port 56 flows into the spool 5.
Enter the chamber 57 of 1 and open the orifice 58.
While the oil amount is controlled by
By reaching inside and flowing into the steering port 55, a force is applied to the spool 51 to move it to the right.

At this time, a part of the working oil flows through the orifice 60.
The liquid flows into the second damper chamber 54 through the second damper chamber 54 and generates a pressure approximately equal to that of the inlet port 56 in the second damper chamber 54 . As a result, the spool 51 is moved to the right, the cargo handling port 55a is opened, and hydraulic oil flows into it.

At this time, when the cargo handling system device is operated, the amount of hydraulic oil flowing into the cargo handling port 55a increases, and the pressure of this oil causes the cargo handling port 55a to be opened further.

(Problem to be solved by the invention) When the operation of the cargo handling system device is released in the above state, the hydraulic pressure in the cargo handling port 55a decreases rapidly, and from the inflow port 56 to the cargo handling discharge port 55a.
Operating oil flows into. At this time, spool 51
moves toward the second damper chamber 54 so as to throttle the cargo handling port 55a, but the working oil in the second damper chamber 54 flows out through the orifice 60, but the amount is limited and the moving speed of the spool 51 is limited. is slow, a large amount of working oil flows into the cargo handling discharge port 55a all at once, and the flow rate flowing into the steering conduit via the steering port 55 is drastically reduced. As a result, the oil pressure in the steering conduit, which is required to have a constant oil pressure, decreases, resulting in poor responsiveness to steering operations.

The present invention has been made to solve the above-mentioned problems, and its purpose is to prevent fluctuations in the fluid pressure of the working fluid and the first discharge port that supplies the first hydraulic circuit system pipeline, which has large fluctuations in fluid pressure. The second hydraulic circuit system pipe that is required to have a small
When dividing the fluid to the discharge port of the hydraulic circuit, it is possible to suppress the influence on the second hydraulic circuit system based on the fluid pressure fluctuation of the first hydraulic circuit system, and the hydraulic circuit installed in an industrial vehicle such as a forklift can be suppressed. In other words, by adopting a flow divider valve that divides hydraulic oil into the cargo handling hydraulic circuit and the steering hydraulic circuit, excellent responsiveness to steering operations can be maintained even during cargo handling operations, and the spool can be used as the primary hydraulic circuit. It is an object of the present invention to provide a flow divider valve that can adjust the speed of movement when moving in the direction of closing a discharge port, and can alleviate the impact force when the spool comes into contact with the wall surface of a damper chamber.

Structure of the Device (Means for Solving Problems) In order to achieve the above-mentioned object, this device includes a fluid inlet port communicating with a fluid source, and a working fluid supplied from the fluid source through the fluid inlet port. The working fluid supplied from the fluid source through the first discharge port that supplies the fluid to the first hydraulic circuit system conduit where fluid pressure fluctuations are large, and the fluid inflow port is required to have small fluctuations in fluid pressure. a second discharge port that supplies a second hydraulic circuit system pipe line; a spool that moves within the valve chamber to open and close the first and second discharge ports; and the spool closes the first discharge port. a biasing means for biasing the spool in the direction; a damper chamber defined in the valve chamber on a side where the spool is biased by the spool; and communication between the damper chamber and the fluid inflow port. A damper hole formed in the spool is provided with a relief passage communicating from the damper chamber to at least one of a fluid inflow port and a first discharge port, and the relief passage is provided with a damper hole formed in the spool. The gist thereof is a flow dividing valve in which an opening on the chamber side is formed at a position spaced apart by a predetermined distance from the inner end of the damper chamber on the side on which the spool is biased.

(Function) This invention adopts the above-mentioned means, so that when fluid pressure fluctuates in the first hydraulic circuit system and the fluid pressure at the first discharge port becomes lower than the fluid pressure at the second discharge port, The spool moves in a direction that closes the first discharge port. At this time, the fluid in the damper chamber flows out to at least either the fluid inlet port or the first discharge port through the relief passage in addition to the damper hole, so the spool quickly moves to the first discharge port. will be closed. As a result, a large amount of fluid will not flow into the first discharge port all at once, and the flow rate flowing into the second discharge port will not suddenly decrease sharply. Therefore, a drop in fluid pressure in the second discharge port due to a drop in fluid pressure in the first discharge port is avoided.

(Example) Hereinafter, the first example in which this invention was embodied in a diversion valve in the hydraulic circuit of a forklift will be described in 1 to 3.
This will be explained in detail according to the diagram.

In FIG. 3, working oil as a working fluid stored in an oil tank 1 as a fluid source flows into a diversion valve D of the present invention through a fluid inflow pipe 2a by the action of an oil pump 2. The hydraulic oil is divided into two directions by a diverter valve D, and one side is sent to the power steering device 4, which improves the operability of the steering wheel 4a, through a steering system pipe 3 as a second hydraulic circuit system pipe. and the other is sent to the control valve 6 via a cargo handling system pipe 5 as a first hydraulic circuit system pipe. The flow direction of the operating oil in the control valve 6 is changed by operating a switching lever 7, and the lift cylinder 8, tail cylinder 9, etc. are driven to move the fork at any time.

1 and 2 show a diversion valve D, in which both ends of a through hole 11 provided in a housing 10 are closed with bolts 12 to form an accommodating portion 13 as a valve chamber. This housing portion 13 is divided into two into front (right side) and rear damper chambers 15 and 16 by a substantially cylindrical spool 14 that is slidably disposed therein. Bolt 12 on the front damper chamber 15 side
One end of a push spring S as a biasing member is supported by a spring mounting member 12a fixedly attached to the spring mounting member 12a, and the push spring S biases the spool 14 toward the rear damper chamber 16 side. Furthermore, a stopper 20 is fixed to the bolt 12 on the rear damper chamber 16 side, and the rear position of the spool 14 is regulated by this stopper 20. In the accommodation portion 13 of the housing 10, the spool 14 is moved back and forth by the biasing force of the push spring S and changes in hydraulic pressure.

The housing 10 also includes a fluid inflow port (hereinafter referred to as an inflow port) 1 that communicates with the inflow pipe 2a, the steering system pipe 3, and the cargo handling system pipe 5, respectively.
7. Discharge port for cargo handling (hereinafter referred to as cargo handling port)
18. Steering discharge ports (hereinafter referred to as steering ports) 19 are arranged and penetrated from the rear to the front.

The front outer peripheral surface of the spool 14 is connected to the housing 1.
A closed surface 28 slides on the inner circumferential wall of the accommodating portion 13 of No. 0, and an open recess 29 is formed behind the closed surface 28. Then, as shown in Figure 1,
Inside the accommodation portion 13 of the housing 10, the spool 14 is urged backward by a push spring S as an urging member, and the cargo handling port 18 is closed by the closing surface 28. The gap C1 between the front end and the steering port 19 allows the front damper chamber 15 and the steering system conduit 3
are in communication.

Further, as shown in FIG. 2, the pressure of the working oil that has flowed into the inflow port 17 causes the spool
4 is moved forward against the force of the push spring S, the gap C1 on the steering port 19 side is narrowed at the closing surface 28, and a gap is created between the rear end of the closing surface 28 and the cargo handling port 18. The gap C2 allows the open recess 29 to communicate with the cargo handling system conduit 5.

In addition, a stopper 20 is provided at the rear of the housing 10.
A fluid movement passage 21 as a relief passage is provided in a bent state at a position spaced forward by a distance l from
7 and the cargo handling port 18, check valves 2 are provided respectively.
2. The check valve 22 prevents the operating oil from flowing out from the inflow port 17 and the cargo handling port 18 to the rear damper chamber 16 via the fluid movement path 21, and also prevents the hydraulic oil from flowing out into the rear damper chamber 16.
The hydraulic oil is allowed to flow into both ports 17 and 18 from there.

A first orifice 30 having a smaller cross-sectional area than the fluid movement path 21 is provided through the rear wall of the open recess 29 of the spool 14, thereby communicating the open recess 29 with the rear damper chamber 16. Further, a passage hole 31 is provided in the bottom wall of the open recess 29, and the open recess 29 and the chamber 23 of the spool 14 are communicated through the passage hole 31. A part of the working oil supplied from the oil tank 1 into the open recess 29 through the inflow port 17 is sent into the rear damper chamber 16 through the first orifice 30, increasing the pressure inside. . Furthermore, open recess 2
The remaining hydraulic oil in 9 passes through the passage hole 31 and flows into the chamber 23 of the spool 14.

The front part of the spool 14 is formed to have a large inner diameter, and the rear end of the push spring S is located between the outer peripheral surface of the small-diameter cylindrical communication member 34 attached to the stepped part 33 and the inner peripheral surface of the spool 14. Retained. Also, a check valve storage member 35, which is also cylindrical, is fixed to the front end of the communication member 34, and a pair of upper and lower outflow holes 36 transparently provided at the rear end allow the spool 14 to
The chamber 23 communicates with the inside of the front damper chamber 15 via a communication member 34. Further, a through hole 37 is formed in the front end surface of the storage member 35, and a check valve 38 made of a pressure spring and a spherical valve body is attached near the through hole 37 on the inner surface of the front end surface.

The working oil advancing inside the chamber 23 of the spool 14 passes through the communication member 34 and is transferred to the storage member 35.
It flows out into the front damper chamber 15 from the outflow hole 36 inside, and further flows into the steering port 19 from the gap C1.
It flows into the steering system conduit 3 through the.

Further, the check valve 38 prevents the working oil flowing back from the steering system pipe line 3 from flowing into the chamber 23 of the spool 14 . That is, when a kickback phenomenon occurs in the steering system conduit 3, the working oil that flows backward flows into the storage member 35 through the through hole 37 and presses the check valve 38 against the front end surface of the communication member 34. As a result, communication between the storage member 35 and the communication member 34 is cut off, and the hydraulic oil that has flowed into the storage member 35 from the front damper chamber 15 through the outflow hole 36 and the through hole 37 passes through the communication member 34 and enters the chamber 23. reaching the normal balance of the entire hydraulic circuit is avoided.

Now, the operation of the flow dividing valve configured as described above will be explained below.

When the pump 2 operates, a portion of the working oil that flows from the oil tank 1 into the open recess 29 through the inflow port 17 is sent into the rear damper chamber 16 via the first orifice 30, and the rest flows through the passage hole 31. It then reaches the inside of the chamber 23. This working oil moves forward in the same chamber 23, and while applying a forward moving force to the spool 14, passes through the communication member 34 and reaches the storage member 35, and then flows from the outflow hole 36 into the front damper chamber. leaked within 15 days,
The working oil flows into the steering system conduit 3 via the steering port 19. After operating the accelerator, the vehicle starts running while its direction is controlled by operating the handlebar 4a.

On the other hand, the working oil sent into the rear damper chamber 16 gradually increases the pressure inside the damper chamber 16. The spool 14 moves forward within the accommodation portion 13 of the housing 10 due to the forward force applied to the spool 14 as the working oil passes through and the pressure increase in the rear damper chamber 16 .

As the spool 14 moves forward, the closing surface 28 moves forward, opening the cargo handling port 18 as shown in FIG. flow, prepare for cargo handling operations.

When a cargo handling operation is performed in the above state, the spool 14 is still moved forward due to the large amount of hydraulic oil flowing into the gap C2 of the cargo handling port 18, and the pressure in the cargo handling system pipe 5 becomes extremely high. At this time, as shown in FIG. 2, since the steering port 19 is in a constricted state, fluctuations in the pressure of the working oil in the steering system conduit 3 are small.

Then, when the cargo handling operation is stopped due to the completion of the cargo handling operation, the pressure in the cargo handling system pipe 5 suddenly decreases, and the pressure in the open recess 29 is reduced to the rear damper chamber 16.
lower than the internal pressure.

At this moment, the working oil in the rear damper chamber 16 flows out through the first orifice 30 and flows into the fluid movement path 21, presses the check valve 22 on the cargo handling port 18 side, and flows into the opening recess 29. Flow into. Therefore, the pressure inside the rear damper chamber 16 is reduced, and the spool 14 quickly moves rearward within the accommodation section 13 of the housing 10, closing the cargo handling port 18 with its closing surface 28. After this, the working oil in the fluid movement path 21 presses the check valve 22 on the inflow port 17 side and enters the open recess 29, and due to further pressure reduction in the rear damper chamber 16, the spool 14 continues to move backward. .

Therefore, when the cargo handling operation is stopped, a large amount of hydraulic oil will not flow all at once into the cargo handling port 18 from the inflow port 17 as the pressure in the cargo handling system conduit 5 decreases drastically. On the other hand, even if the pressure in the cargo handling system pipe 5 decreases sharply and the pressure in the pipe 5 becomes lower than the pressure in the steering system pipe 3, the spool 14 can quickly move to the cargo handling port. 18 is closed, steering port 1
This also prevents the flow rate of the working oil flowing into 9 from being drastically reduced. Therefore, the performance of the power steering device 4 does not deteriorate temporarily due to a decrease in the pressure within the steering system pipe 3. This ensures stable operability of the handle 4a at all times.

When the spool 14 reaches a position spaced apart from the stopper 20 by a distance l, the spool 14 closes the opening of the fluid movement path 21 and blocks communication between the rear damper chamber 16 and the open recess 29. Then, the working oil in the rear damper chamber 16 passes only through the first orifice 30, which has a smaller cross-sectional area than the fluid movement path 21, and enters the open recess 29. As a result, the amount of hydraulic oil flowing out decreases, the backward movement speed of the spool 14 decreases, and the impact when the spool 14 abuts against the stopper 20 also decreases, causing an unpleasant collision noise between the spool 14 and the stopper 20. is avoided.

In addition, due to the action of the check valve 38 provided in the storage member 35, the entry path of the working oil flowing back from the steering port 19 into the spool 14 is blocked. Therefore, even if a foreign object or the like is present in the fluid transfer path 21 and the flow of the working oil passing therethrough is slow, and the backward movement of the spool 14 is slightly delayed after the cargo handling operation is stopped, the depressurized cargo handling port 18
Operating oil is prevented from flowing into the steering port 19 from the steering port 19.

In this embodiment, at the moment when the cargo handling operation is stopped and the pressure in the cargo handling system pipe 5 is drastically reduced, the spool 14 exhibits excellent responsiveness and retreats inside the housing 10, causing the cargo handling system pipe 5 to Communicating cargo handling port 1
8 is closed. As a result, despite the pressure drop in the cargo handling system pipe 5, a large amount of hydraulic oil does not flow into the cargo handling system pipe 5 all at once, and a drop in the hydraulic pressure in the steering system pipe 3 is avoided. , stable steering operation is guaranteed.

Note that this invention is not limited to the above-described embodiments; for example, the present invention is not limited to the above-mentioned embodiments.
As long as it does not deviate from the spirit of this invention, such as simplifying the configuration by communicating only 8 with the rear damper chamber 16 via the fluid movement path 21, or applying it not only to industrial vehicles but also to various hydraulic equipment, etc. Of course, arbitrary changes are possible.

Effects of the invention As detailed above, according to this invention, even if a large pressure fluctuation occurs in the first hydraulic circuit system pipe where the fluid pressure fluctuates greatly, the first hydraulic circuit system pipe is activated. Since the first discharge port for supplying oil is quickly closed by the spool, the flow rate to the second hydraulic circuit system pipe line, which requires small fluctuations in fluid pressure, does not decrease drastically. The influence on the second hydraulic circuit system pipeline can be suppressed, and it can be used as a hydraulic circuit installed in industrial vehicles such as forklifts, that is, a flow divider valve that divides working oil into a cargo handling hydraulic circuit and a steering hydraulic circuit. If adopted, it is possible to maintain excellent responsiveness to steering operations even during cargo handling operations, and when the spool moves in the direction of closing the first discharge port, the damper is moved as the spool moves. By closing the opening of the escape passage in the chamber, the moving speed of the spool is adjusted, and the impact force when the spool comes into contact with the wall of the damper chamber can be reduced.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the diverter valve of this invention, Figure 2
The drawings are a sectional view showing a change from FIG. 1, FIG. 3 is a schematic diagram showing a hydraulic circuit, and FIG. 4 is a sectional view showing a conventional example. An oil tank 1 as a fluid source, a steering system pipe 3 as a second hydraulic circuit system pipe, a cargo handling system pipe 5 as a first hydraulic circuit system pipe, an accommodation section 13 as a valve chamber, and a spool 14. , damper chamber 16,
A fluid inflow port 17, a cargo handling discharge port 18 as a first discharge port, a steering discharge port 19 as a second discharge port, a fluid movement path 21 as a relief passage, and a first orifice 30 as a damper hole. Push spring S as a force member.

Claims (1)

[Claims for Utility Model Registration] A fluid inlet port that communicates with a fluid source, and a working fluid supplied from the fluid source through the fluid inlet port to a first hydraulic circuit system conduit where fluid pressure fluctuations are large. a first discharge port; and a second discharge port that supplies the working fluid supplied from the fluid source through the fluid inflow port to a second hydraulic circuit system pipe line that is required to have small fluctuations in fluid pressure. a spool that moves within the valve chamber to open and close the first and second discharge ports; a biasing means that biases the spool in a direction in which the spool closes the first discharge port; a damper chamber defined on a side of the spool on which the spool is biased; and a damper hole formed in the spool to communicate the damper chamber with the fluid inflow port. An escape passage communicating from the damper chamber to at least one of a fluid inflow port and a first discharge port is provided, and the escape passage has an opening on the damper chamber side where the spool in the damper chamber is energized. A diverter valve formed at a predetermined distance from the inner end of the side.