JPH0140344Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is intended to reduce the initial pressure rise of the pressure fluid supplied to the hydraulic clutch in a torque converter vehicle of an industrial vehicle such as a forklift. This invention relates to a modulator valve that allows smooth connection of a hydraulic clutch.

(Prior art) As shown in Fig. 1, the modulator valve A is
It is provided in communication with a conduit D branched from the discharge conduit C of the inching valve device B, and supplies pressurized fluid sent from the oil pump P and adjusted to a constant pressure by the regulator valve R to the inching pedal. When the pressure on E is released, the hydraulic clutch F
At the initial stage of operation of the inching valve device B, which sends the fluid to the tank T, a part of the pressure fluid is released to the tank T side to alleviate the rise in fluid pressure to the hydraulic clutch F, and to smoothly connect the torque converter G to forward or reverse drive. It has the function of making the user perform the following functions.

By the way, FIG. 2 is a graph showing the modulation characteristics of modulator valve A, and the modulation time shown in this graph, that is, the valve operation time, is the pressure fluid divided by the piston 6 in modulator valve A. It is determined by the volume of the chamber 15 and the size of the orifice 18 that introduces the working fluid of the hydraulic clutch F into this pressure fluid chamber 15. Therefore, if the volume of the pressure fluid chamber 15 is increased or the orifice 18 is made smaller, , the valve operation time can be extended.

Conventional means for changing the valve operating time of such modulator valve A include an adjustment method by changing the volume of the sub-accumulator 30 shown in FIG. 4, and an operation method using a variable orifice 34 shown in FIG. A fluid flow path adjustment method is known. The former sub-accumulator system has a pressure liquid chamber 15.
The valve operating time is changed by connecting the sub-accumulator 30 to the discharge port 31 of the sub-accumulator 30 and changing the volume by changing the position of the stopper 33 that determines the stroke of the piston 32 of the sub-accumulator 30. In the orifice system, a variable orifice 34 is provided in the flow path for introducing the working fluid of the hydraulic clutch F into the pressure fluid chamber 15, thereby controlling the flow rate and changing the valve operating time.

The structure and operation of the modulator valve A shown in FIGS. 4 and 5 are the same as those of the embodiment of the present invention described later, except for the valve operation time changing mechanism, so each component are given the same reference numerals as in FIG. 1, and their explanation will be omitted.

(Problems to be solved by the invention) In the above-mentioned conventional modulator valve with a mechanism for changing the valve operating time, the former sub-accumulator type has the drawbacks of a complicated structure and an increase in size. In the case of the latter variable orifice method, in order to release the hydraulic clutch,
When the inching pedal E is depressed, residual pressure is generated for a while in the flow path between the pressure liquid chamber and the variable orifice, and as a result, a driving force is generated even though it is neutral, or the inching pedal E If the depression and release of the depression are performed continuously, there is a drawback that a predetermined modulation characteristic may not be obtained.

Therefore, the technical problem to be solved by the present invention is to provide a modulated valve that can change the valve operating time without causing the above-mentioned problems.

(Means for solving the problem) The technical means for solving the above problem is to install a valve spool on one side of the cylindrical hole formed in the valve body.
A piston is fitted concentrically into the center of the cylindrical hole, a compression spring is interposed between the valve spool and the piston, and the valve spool and the peripheral wall of the cylindrical hole are connected to the discharge side of the inching valve device. A first pressure liquid chamber communicating with the pipe line is formed, and a discharge port communicating with the first pressure liquid chamber at the pushing position of the valve spool is provided in the valve body, and a discharge port is provided on the other side of the cylindrical hole. A partition wall is provided that partitions a second pressure liquid chamber adjacent to the piston and a liquid storage chamber that communicates with the discharge side pipe of the inching valve, and the partition wall communicates the second pressure liquid chamber and the liquid storage chamber. In the modulator valve, the valve body is provided with a discharge port that is opened and closed by the piston and communicates with the second pressure fluid chamber, and the discharge port is provided with a discharge port that is opened and closed by the piston and communicates with the second pressure fluid chamber. An opening/closing valve or a variable orifice is provided to control the outflow of pressure fluid in accordance with the above.

(Function) Therefore, the operating time of the modulator valve, ie the pressure fluid delivered to the hydraulic clutch,
The initial pressure rise rate is changed by changing the amount of pressure fluid flowing out from the discharge port opened and closed by the piston.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIG. 1. In the figure, 1 is a valve body of a modulator valve A, and the valve body 1 has a cylindrical hole formed with a small diameter hole 2 on the left side, a large diameter hole 3 in the center, and a medium diameter hole 4 on the right side. . The left side of the valve spool 5 is slidably and tightly fitted into the small diameter hole 2 of the cylindrical hole, and a piston 6 having a U-shaped cross section is slidably and tightly fitted into the large diameter hole 3. The left end of the valve spool 5 faces a first pressure liquid chamber 7 formed on the left side of the valve body A, and this first pressure liquid chamber 7 is always connected to the branch pipe D via an inflow port 8. 9 is a first valve formed on the left side of the valve body 1.
The discharge port 9 is normally closed by the valve spool 5, and opens when the valve spool 5 moves forward to open the first pressure liquid chamber 7.
is connected to tank T.

Further, the right side of the valve spool 5 is inserted into the large diameter hole 3 to a substantially intermediate position, and constitutes a stopper 10 that restricts the leftward movement end of the piston 6.
It is always biased to the right by a compression spring 11 interposed between the flange 5a and the flange 5a.

A bottomed cylindrical valve cap 12 is fitted into the right end of the large diameter hole 3 of the cylindrical hole, and this valve cap 12 constitutes the medium diameter hole 4 of the cylindrical hole, and is located on the right side of the piston 6. The moving end is regulated. An orifice valve 13 having a U-shaped cross section is slidably and tightly fitted into the medium-diameter hole 4, and the orifice valve 13 allows the inside of the medium-diameter hole 4 to be connected to the inside of the medium-diameter hole 4 by means of a bottom plate 14 as a partition wall. The second adjacent to the piston 6
It is divided into a pressure liquid chamber 15 and a liquid reservoir chamber 17 which communicates with the branch pipe D through an inflow port 16. Further, an orifice 18 is formed in the bottom plate 14 of the orifice valve 13 to communicate the second pressure liquid chamber 15 and the liquid storage chamber 17, and the orifice valve 13 is normally connected to the second pressure liquid chamber 15 by a compression spring 19. Pressed to the side. 20 is valve body 1
a second discharge port formed on the right side of the
The discharge port 20 is always connected to the orifice valve 1.
3, and is opened when the orifice valve 13 moves to the right to connect the second pressure liquid chamber 15 to the tank T.

In the modulator valve A configured as described above, the valve operating time changing mechanism will be explained. A third discharge port 21 is formed in the valve body 1 and communicates with the right end of the large diameter hole 3, and the discharge port 21 is normally closed by the piston 6 when the piston 6 moves to the left. The second pressure liquid chamber 15 is communicated with the tank T by being opened at times. Further, an orifice 22 is provided in the third discharge port 21, and an on-off valve 23 is provided downstream of the orifice 22.
is provided.

This embodiment is configured as described above,
The effect will be explained below. The illustrated state shows a state in which the hydraulic clutch F is inoperative, the piston 6 and the valve spool 5 are at the most separated position by the compression spring 11, and the orifice valve 1
3 is located closest to the piston 6 by a compression spring 19, and each discharge port 9, 20, 2
1 are each closed.

In this state, when the inching pedal E is released and pressure fluid flows out from the inching valve device B to the discharge pipe C, this pressure fluid is supplied to the hydraulic clutch F and the modulator valve A is supplied from the branch pipe D. The first through the inflow port 8.
The pressure fluid flows into the pressure fluid chamber 7 and pushes the valve spool 5 to the right against the compression spring 11, so that the first pressure fluid chamber 7 communicates with the first discharge port 9, and the pressure fluid flows therethrough. is returned to tank T through As a result, the hydraulic pressure of the hydraulic clutch F is suppressed to a low pressure. On the other hand, the pressure fluid flows into the liquid reservoir chamber 17 through the inflow port 16, and from this flows into the second pressure liquid chamber 15 through the orifice 18, and flows into the second pressure liquid chamber 15 through the piston 6.
is pushed to the left against the compression spring 11.

By this movement of the piston 6, the second pressure liquid chamber 15 communicates with the third discharge port 21, but in this case, when the on-off valve 23 related to the discharge port 21 is closed, As the spring force of the compression spring 11 gradually increases due to the movement of the piston 6, the operating pressure of the hydraulic clutch F gradually increases. On the other hand, when the on-off valve 23 is open, a part of the pressure fluid is returned to the tank T through the orifice 22 of the discharge port 21. This is slower than when the valve 23 is closed, and therefore the operating pressure of the hydraulic clutch F increases at a slower rate.

Note that as the piston 6 continues to move and comes into contact with the stopper 10 of the valve spool 5, they move together to the left due to the difference in pressure receiving area and close the first discharge port 9. Therefore, the hydraulic pressure of the hydraulic clutch F increases to a predetermined pressure.

As mentioned above, by opening and closing the on-off valve 23, the rate of increase in the operating pressure of the hydraulic clutch F,
In other words, the operating time of modulator valve A is changed, and the solid line in FIG. 2 shows when the on-off valve 23 is closed, and the broken line shows when it is opened. This corresponds to the point at which the piston 6 starts moving, and point b is at the valve spool 5.
This corresponds to the time when the stopper 10 is contacted.

When the inching pedal E is depressed to release the hydraulic clutch F, the discharge pipe C is connected to the tank T, and the pressure of the pressure fluid in the hydraulic clutch F is reduced, so that the liquid reservoir chamber 17 and the second Since the pressure in the pressure liquid chamber 15 also decreases, the piston 6 is returned to its original position by the restoring force of the compression spring 11. Further, the pressure fluid in the liquid storage chamber 17 is returned to the tank T via the inflow port 16 and the branch pipe D, and furthermore, the pressure fluid in the second pressure liquid chamber 15 is transferred to the right side of the orifice valve 13 against the compression spring 19. and returns to the tank T through the second discharge port 20. Therefore, no residual pressure is generated in the pressure fluid flow path related to the modulating valve, and the pressure is smoothly reduced.

Next, another embodiment of the present invention will be explained based on FIG. In this embodiment, a variable orifice 24 is provided in the third discharge port 21 in place of the orifice 22 and on-off valve 23 in the previous embodiment, and the other configurations are the same as in the previous embodiment. Therefore, according to this embodiment, the variable orifice 24 allows the tank T to be discharged through the discharge port 21.
By appropriately controlling the flow rate of the pressure fluid flowing out, it is possible to continuously change the operating time of the modulating valve A.

It should be noted that changing the operating time of the modulate valve A, that is, changing the operating time of the on-off valve 2 in the embodiment shown in FIG.
3 opening/closing operation, variable orifice 24 shown in FIG.
The throttle operation is performed to correspond to the light and heavy loads of the vehicle, thereby making it possible to obtain a suitable starting feeling.

(Effects of the invention) As described above, the invention controls the amount of pressure fluid flowing out from the second pressure liquid chamber by using the on-off valve or variable orifice provided in the discharge port communicating with the second pressure liquid chamber. This makes it possible to change the operating time of the modulator valve, which has the advantage of requiring fewer parts and a smaller space compared to the conventional accumulator method, as well as reducing pressure fluid flow. This provides smooth modulator function without problems such as residual pressure occurring in the flow path.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a modulator valve showing an embodiment of the present invention, Fig. 2 is a hydraulic pressure control performance diagram of the modulator valve, and Fig. 3 is a longitudinal sectional view showing another embodiment of the invention. The top view, FIG. 4, and FIG. 5 are longitudinal sectional views showing conventional examples, respectively. 1...Valve body, 5...Valve spool, 6...
Piston, 7...First pressure liquid chamber, 11...Compression spring, 1
3... Orifice valve, 15... Second pressure liquid chamber, 17
...liquid storage chamber, 21...discharge port, 22...orifice, 23...on/off valve, 24...variable orifice.

Claims (1)

[Scope of utility model registration request] A valve spool is fitted into one side of a cylindrical hole formed in the valve body, a piston is fitted concentrically into the center of the cylindrical hole, a compression spring is interposed between the valve spool and the piston, and the valve spool and the piston are fitted concentrically. The circumferential wall of the cylindrical hole forms a first pressure liquid chamber that communicates with the discharge side conduit of the inching valve device, and further includes a discharge port that communicates with the first pressure liquid chamber at the pushing position of the valve spool. A partition wall is provided in the valve body and partitions the other side of the cylindrical hole into a second pressure liquid chamber adjoining the piston and a liquid reservoir chamber communicating with the discharge side conduit of the inching valve, the partition wall The modulator valve has an orifice that communicates between the second pressure liquid chamber and the liquid storage chamber, and the valve body has a discharge port that is opened and closed by the piston and communicates with the second pressure liquid chamber. A modulator valve for a torque converter vehicle, wherein the discharge port is provided with an on-off valve or a variable orifice for controlling the outflow of pressure fluid according to the weight and weight of the vehicle load.