JPS5822642B2 - Ryuutaiatsuriyokusaniyotsute Sadousareruriyuuriyoseigyoben - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a flow control valve in a fluid circuit, and controls the flow rate of fluid in the fluid circuit by moving a balance piston that operates in response to a pressure difference before and after the flow control valve. The present invention relates to a flow control valve operated by a fluid pressure difference.

For example, if the operating speed of a fluid pressure operated device such as a fluid pressure cylinder used in a cargo handling vehicle or material dumping machine is accelerated more than necessary under heavy load conditions, the fluid pressure operated device or the device in which it is installed may be damaged. Significant shock loads are generated on the mechanical systems being operated, and there is a high risk of damage to the hydraulically operated equipment and mechanical systems.

Therefore, conventionally, it is known that a fluid circuit is provided with a flow control valve that can reduce the speed of the hydraulically operated device by narrowing the passage area of the fluid discharged from the hydraulically operated device. In the flow control valve, the effective passage area for the discharged fluid is constant before and after deceleration of the operating device, so if the load applied to the operating device is very small, the discharge fluid passes through the flow control valve. The flow rate of the fluid passing through the flow rate control valve decreases, causing the time required for the operation of the operating equipment to become longer than necessary, resulting in an inconvenience that reduces work efficiency. Not only does the flow rate become large and a sufficient deceleration effect on the operating equipment cannot be obtained, but also a high surge pressure is generated during deceleration, giving a shock to various parts of the device and causing damage to the various parts of the device.

The present invention has been proposed in view of the above, and it is possible to control the flow rate and hence the flow velocity of fluid flowing through a fluid circuit to be constant regardless of the magnitude of the load on the fluid pressure operated equipment provided in the fluid circuit. Another object of the present invention is to provide a flow rate control valve that is capable of decelerating by a certain value as necessary, and can always provide an optimal deceleration or buffering effect to the fluid pressure operated equipment.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 3
and an outflow lower connected to an oil sump (not shown) are each opened.

Inside the casing, there are a first chamber 4 communicating with the inflow port 3, a second chamber 6 communicating with the outflow lower, and these two chambers 4.
Intermediate holes 5 are respectively formed to allow the holes 6 to communicate with each other.

The intermediate hole 5 is provided with a throttle valve 8 for restricting the hole 5 to create a fluid pressure difference between the first chamber 4 side and the second chamber 6 side.

The throttle valve 8 is formed integrally with an adjustment screw 9, and by rotating the adjustment screw 9, the throttle valve 8 can be moved to change the cross-sectional area of the opening of the intermediate hole 5. ing.

A balance piston 10 is slidably inserted into the second chamber 6, and the balance piston 10 is supported by a compression spring 15 interposed between the end wall of the casing 2 and the end surface of the balance piston 10. , the outflow lower is biased in the direction of opening.

A spindle 11 is slidably fitted into a through hole along the center line of the balance piston 10.

A flange 12 is provided at one end of the spindle 11, and a stopper 17 is provided at the other end.

A compression spring 14 is interposed between the shoulder 13 provided on the casing 2 side and the flange 12, and the spindle 11 is normally biased in the direction in which the stopper 17 comes into contact with the end surface of the balance piston 10. There is.

Further, a press rod 16 is slidably fitted into the end wall of the casing 2 so as to face the end surface of the spindle 11 .

stop. the compression spring 1 by pushing out the pressure rod 16 in the direction of the spindle 11 by any suitable means.
4 on the spindle 11 can be canceled out.

Thus, the spindle 11 and the pressing rod 16 constitute the biasing force/releasing means of the present invention.

Now, the discharged oil led from the hydraulic cylinder 1 passes through the inlet 3, the first chamber 4, the intermediate hole 5, and the second chamber 6 and reaches the outflow lower. In addition to being throttled to a certain extent, the flow rate is normally controlled by the balance piston 10 so that the flow rate is always constant.

That is, when discharged oil from the cylinder 1 flows into the casing 2, the load applied to the cylinder 1 causes the oil pressure in the front side of the throttle valve 8, that is, in the first chamber 4 to rise, and the oil pressure in the second chamber 6 to increase. A pressure difference is generated between the hydraulic pressure and the balance piston 10 against the spring force of the compression springs 14 and 15.
Press and move it to the left in Figure 1.

If the pressure difference is large, the amount of movement of the balance piston 10 increases, reducing the opening area of the outflow lower, and if the pressure difference is small, the amount of movement of the balance piston 10 decreases, increasing the opening area of the outflow lower. However, in the end, the flow rate of the discharged oil flowing out from the outflow lower is maintained at a constant amount regardless of the magnitude of the load on the cylinder 1, that is, the magnitude of the pressure of the fluid flowing in from the inflow port 3.

Therefore, even if an excessive load is applied to the hydraulic cylinder 1 and the pressure of the discharged oil increases and the hydraulic pressure in the first chamber 4 increases, the action of the balance piston 10 that changes the cross-sectional area of the outflow lower reduces the hydraulic pressure. The cylinder 1 can always operate at a constant operating speed, and various dangers associated with acceleration of the operating speed of the hydraulic cylinder 1 can be prevented.

Furthermore, when the hydraulic rod 16 is pressed inward into the casing 2, the spindle 11 is moved to the left in FIG. acts, and as a result, the balance position of the balance piston 10 relative to the differential pressure between the first and second oil chambers 4 and 6 moves a predetermined amount to the left in FIG. 1, that is, in the direction of closing the outflow lower. .

That is, by pressing the pressing rod 16 inward of the casing 2 as necessary, the operating speed of the hydraulic cylinder 1 can be reduced by a fixed value regardless of the magnitude of the load applied to the cylinder 1, and the hydraulic cylinder 1 is decelerated. It is possible to prevent damage to the equipment system and ensure work safety by preventing shocks and the like that would occur if the equipment continues to operate without being activated.

FIG. 2 shows another embodiment of the invention, in which parts corresponding to those in FIG. 1 are indicated by the same reference numerals used in FIG. 1 with a prime added.

The casing 2' of the flow control valve is attached to the lower head of the hydraulic cylinder, and the first chamber 4' in the casing 2' is
It communicates with the interior of the hydraulic cylinder 1' through an inlet 3' provided in the head wall of the hydraulic cylinder 1'.

The first chamber 4' communicates with the second chamber 6' through an intermediate hole 5', the cross-sectional area of which can be varied by means of a throttle valve 8' adjusted by an adjusting screw 9'. .

The second chamber 6' is provided with an outflow lower part' whose cross-sectional area can be changed in accordance with the movement of the balance piston 10' within the second chamber 6'.

Spindle 1 along the center line of balance piston 10'
1' is slidably passed through the hydraulic cylinder 1', and one end of the spindle 11' projects inward of the hydraulic cylinder 1'.

and the end wall of the casing 2' and the balance piston 10.
A compression spring 15' is interposed between the end face of the hydraulic cylinder 1' and a shoulder part 15' provided on the head wall of the hydraulic cylinder 1'.
A compression spring 14' is interposed between 3' and a flange 12' at the end of the spindle 11' that projects into the hydraulic cylinder 1'.

Therefore, when the piston 16' in the hydraulic cylinder 1' moves in the contraction direction, the hydraulic oil in the hydraulic cylinder 1' flows through the inlet 3', the first chamber 4', the intermediate hole 5', the second chamber 6' and the outflow lower. ’ and then discharged.

At this time, due to the load applied under the hydraulic cylinder, the hydraulic pressure on the front side of the throttle valve 8', that is, the first oil chamber 4' and the cylinder 1' increases, and there is a gap between the hydraulic pressure in the second oil chamber 6' and the hydraulic pressure in the second oil chamber 6'. A differential pressure is generated, and this differential pressure moves the balance piston 10' to the left in FIG. 2 against the biasing force of the compression springs 14' and 15'. The flow rate of discharged oil discharged from the outflow lower' can always be kept constant regardless of the magnitude of the downward hydraulic pressure of the hydraulic cylinder.

When the piston 16' moves to a position close to the head wall of the hydraulic cylinder 1', the piston 16' moves the spindle 11' to the left in FIG. 2 against the compression spring 14', and accordingly. Then, the balance piston 10' is moved to the left in FIG. 2 in exactly the same manner as in the first embodiment.

At this time, the flow rate of the discharged oil flowing through the outflow lower ′ is further restricted, and the moving speed of the piston 16 ′ is decelerated by a certain value regardless of the magnitude of the load applied to the hydraulic cylinder 1 ′, so that the piston 16 ′ moves toward the hydraulic cylinder 1 ′. Collision with the head wall of ' is prevented.

As is clear from the above description, according to the present invention, the pressure fluid inlets 3, 3' and the outlet lower, 7' are opened, respectively, and the inlets 3, 3' and the outlet lower, 7' are inside. a casing 2, 2' having intermediate holes 5, 5' formed therein for constant communication between the casings 2, 2'; Throttle valves 8, 8' capable of creating a fluid pressure difference between the inflow ports 3, 3' and the outflow lower, 7'; slidably fitted inside the casings 2, 2', and capable of creating a fluid pressure difference between the inflow ports 3, 3' and the outflow lower, 7'; A balance piston 10, 10' that can variably adjust the opening area of the outflow lower 7' in response; A plurality of compression springs 14, 14' apply a biasing force to increase the opening area of 7'.

15, 15': Since the flow control valve is configured, the balance pistons 10, 10' operate depending only on the fluid pressure difference between the inlet ports 3, 3' side and the outlet lower, 7' side, The opening area of the outflow lower 7' can be automatically and variably adjusted while maintaining a balance with the biasing force of the plurality of compression springs 14, 14', 15°15', and as a result, the opening area of the outflow lower 7' The flow rate and thus the flow velocity of the pressure fluid flowing out to the outside is always kept at an appropriate constant value regardless of the magnitude of the fluid pressure flowing in from the inlet ports 3 and 3', that is, the magnitude of the load on the fluid pressure operated equipment connected to the flow control valve. This can prevent unnecessarily slow operation of the fluid pressure operated equipment, increasing work efficiency, and suppressing the excessive operation of the equipment to prevent damage and breakage, thereby improving work safety. can be ensured.

The plurality of compression springs 14, 14', 15, 15'
The balance piston 10.1
Compression springs 14, 14' acting on 0'.

15, 15', the balance position of the balance pistons io, io' relative to the compression springs 14° 14', 15, 15' is reduced as necessary.
The opening area of the outflow lower 7' can be appropriately moved to the side where the opening area is reduced, and as a result, the flow rate and therefore the flow velocity of the pressure fluid flowing out from the outflow ports γ and γ' can be reduced depending on the load of the fluid pressure operated equipment. The flow rate of the pressure fluid can be automatically reduced by a certain value regardless of its size, and can provide a certain optimal deceleration or buffering effect to the operation of the fluid pressure operated equipment, and the flow rate of the pressure fluid can be kept constant. Together with the effects of controllability, damage to various equipment can be prevented and work safety can be further ensured.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of a flow control valve according to a first embodiment of the present invention, and FIG. 2 is a schematic vertical cross-sectional view of a flow control valve according to a second embodiment of the present invention. 2.2'...Casing, 3,3' inlet, 5
,5'...middle hole, 7,7'...outlet, 8,8'...throttle valve, 10,10'...
...Balance piston, 11, 11'...Spindle as biasing force release means, 14°14'...
... Compression spring, 15, 15'... Compression spring, 16, 16'... Suppressing iron and piston as bias force release means.

Claims (1)

[Claims] 1 Opening the pressure fluid inlets 3, 3' and the outflow lower, 7', respectively, and forming intermediate holes 5, 5' inside which constantly communicate between the inlets 3, 3' and the outflow lower, 7'. The casings 2, 2' are provided in the intermediate holes 5, 5', and apply a throttling effect to the fluid passing through the intermediate holes 5, 5', and the inlets 3, 3', ! = outflow lower, 1' with throttle valves 8, 8' capable of producing a fluid pressure difference; said casing 2;
, 2', and capable of variably adjusting the opening area of the outflow lower, 7' in response to the fluid pressure difference; the balance pistons 10, 10'; The balance piston 1 is provided with two balance pistons.
a plurality of compression springs 14, 14', 15, 15' that apply a biasing force to the outflow lower 7' to increase the opening area of the outflow lower 7'; 14. A flow control valve actuated by a fluid pressure difference, comprising: biasing force release means which can optionally nullify said biasing force of a portion of 14', 15, 15'.