KR100299670B1 - Hydraulic control valve - Google Patents

Abstract

PURPOSE: A hydraulic control valve is provided to prevent vibration from a vehicle in returning the hydraulic control valve, and to improve stability of operation by absorbing impact with forming a piston, a ball check valve and an orifice. CONSTITUTION: A spool(5) is moved down with pressing a push rod(4) by a cam(3) in pushing a pedal(2), and a traveling motor is operated with supplying oil from a pump port(P). Repulsive force of a return spring(9) is offset by a buffering unit of a hydraulic vibration preventive chamber(10). The hydraulic vibration preventive chamber is divided into upper and lower parts, and a ball check valve(14) is formed to supply operating oil unidirectionally. An orifice(18) is integrally formed in a piston(13) to flow oil by connecting the hydraulic vibration preventive chambers. The push rod is reciprocated in the piston and the hydraulic vibration preventive chamber. The volume of upper and lower hydraulic vibration preventive chambers is changed according to the diameter of the push rod.

Description

Hydraulic control valve

The present invention relates to a hydraulic control valve, and more particularly, to provide a hydraulic pilot pressure in a traveling device such as various construction machines to achieve the operational stability of the hydraulic control valve to obtain a rotational speed in proportion to the pilot pressure. It is.

In the conventional hydraulic control valve, when the spring is returned to the neutral position during operation, the spring force that returns the spool is transmitted to the vehicle body as well as the valve, causing severe shaking of the vehicle, which seriously affects the life of the construction machine and the driver's safety. Was to generate.

That is, the conventional hydraulic control valve is pushed down by the pushing force of the foot pedal, and the spool connected to the push rod is operated downward by the pushing force of the push rod to supply, control and provide hydraulic pressure to the push rod. When returning to the neutral position, the spring's rebound force (the original return force) on the spool directly affects the push rod, so that the spring's rebound force is transmitted directly to the body to offset it. The vehicle's shaking (vibration) is induced, which leads to shortening the life of construction equipment, and the working efficiency is deteriorated and, in severe cases, the safety of the driver (worker) is threatened.

In addition, it has been devised variously to add a means such as a shock absorbing spring as a preventive means for solving this.

That is, although there was Patent Application Publication No. 1857 Publication No. 96-18315 and Applicant's 1997 Utility Model Registration Application No. 5837, the publication No. 96-18315 has a hydraulic pressure connected to the discharge pressure of the tank port. The shock absorbing spring is installed in the anti-vibration chamber to absorb elasticity. The shock absorbing spring must finely adjust the elasticity according to the elasticity of the return spring mounted on the spool. According to the spring's elasticity, precise and fine adjustment is difficult and difficult. Operational concerns have required new means to address and correct these shortcomings.

Therefore, the present invention is to solve the above problems of the existing hydraulic control valve, in particular the present invention is installed between the push rod and the spool when the return to the neutral position during the operation of the hydraulic control valve to absorb the sudden elasticity of the return spring It is intended to provide improved operation stability by performing vibration prevention function without mechanical shock absorbing means such as shock absorbing spring.

1 is a cross-sectional view showing a preferred embodiment of the present invention.

Figure 2 is an enlarged cross-sectional view showing the main portion of the present invention.

3 (a) to 3 (d) are cross-sectional views of the working state of the present invention.

* Explanation of symbols for main parts of the drawings

1: valve 2: pedal

3: cam 4: push rod

5: Spool 6: Camshaft

7: euro 8: cylinder

9: Return Spring 10: Hydraulic Vibration Prevention Room

10a, 10b; Upper and lower hydraulic vibration prevention room 11: Guide

12 plate 13 piston

14: ball check valve 15: ball

16: spring 17: distribution hole

18: Orifice 19: Piston Seal

20: Euro

1 is a cross-sectional view showing a preferred embodiment of the present invention, Figure 2 is an enlarged cross-sectional view of the main portion of the present invention, Figure 3 (a) to Figure 3 (d) is a cross-sectional view showing the operating state of the present invention, respectively When the pedal 2 is pushed, the cam 3, which is angularly movable on the cam shaft 6, pushes one push rod 4 so that the lower end of the push rod 4 is guided to the guide 11. (8) pressurizes the plate (12) to compress the return spring (9) and to operate the spool (5) downward to supply hydraulic oil from the pump port P along the flow path (7) to operate the travel system, In the hydraulic control valve (1) which is driven and the spool (5) and the push rod (4) are returned by the restoring force of the return spring (9), the present invention is pushed by the cam (3) of the pedal (2). A push rod 4 integral piston 13 is installed in the hydraulic vibration prevention chamber 10 formed between the push rod 4 and the spool 5 to operate the operation valve. The resilience of the return spring 9 for returning the spool 5 to return to the neutral position of (1) is characterized in that it can be absorbed without causing vibration. Hereinafter, the configuration of the present invention will be described in detail. Same as

In the hydraulic vibration prevention chamber 10 through which the hydraulic pressure of the hydraulic oil is transmitted from the pump port P, a piston 13 is installed to be in close contact with the inner circumferential surface of the hydraulic vibration prevention chamber 10 so that the piston 13 prevents hydraulic vibration. In the state where the seal 13 is divided into the upper and lower parts 13a and 13b, the inside of the hydraulic vibration prevention chamber 10 is raised and lowered by the lifting operation of the push rod 4.

And, the piston 13 is provided with a ball check valve 14 on one side, the ball check valve 14 when the upper hydraulic vibration prevention chamber (10a) is operated at a higher pressure than the lower hydraulic prevention chamber (10b). To be open to

That is, when pressure acts on the lower hydraulic vibration prevention chamber (10b) from the upper hydraulic vibration prevention chamber (13a), it is opened and closes when pressure acts on the upper hydraulic vibration prevention chamber (10a) from the lower hydraulic vibration prevention chamber (13b). It is.

The ball check valve 14 is a structure in which the ball 15 as shown in the ball 15 is elastically supported by the spring 16 to the distribution hole 17 side to be opened and closed. Such a ball check valve 14 is a general multiple check valve Valve) or the like.

In addition, the piston 13 is provided with an orifice 18 which communicates with the ball check valve 14 to the upper and lower hydraulic vibration prevention chamber (10a, 10b).

The hydraulic vibration preventing chamber 10 divided up and down by the piston 13 configures the volume ratio of the upper and lower hydraulic vibration preventing chambers 10a and 10b differently, and the piston 13 is formed integrally with the push. By varying the upper and lower diameters of the rod 4, the volume of the upper hydraulic vibration prevention chamber 10a is smaller than that of the lower hydraulic vibration prevention chamber 10b.

That is, the piston (13) upper piston rod diameter (l) connecting the piston 13 up and down in the hydraulic vibration prevention chamber (10) is smaller than the piston 13 lower push rod diameter (l ') by configuring the piston The upper and lower push rod diameters (l, l ') with respect to (13) is such that the volume of the upper hydraulic vibration prevention chamber 10a is smaller than that of the lower hydraulic vibration prevention chamber 10b.

In addition, a piston seal 19 is formed on the push rod 4 on the upper portion of the hydraulic vibration preventing chamber 10 to minimize leakage flow due to high pressure, and in case of leakage flow that may occur. A low pressure portion of the push rod 4, that is, a flow path 20 connected to the cylinder 8 is formed in the push rod 4 so as to communicate with the piston seal 19.

Unexplained reference numerals in the drawings (T) shows the tank port.

The present invention configured as described above performs a vibration preventing function when returning to the neutral position during the operation of the hydraulic valve (1) to minimize vehicle vibration during the driving operation to exhibit stable operability and to ensure excellent operation stability therefrom. To prevent shortening of life and to ensure the driver's safety. Pushing the pedal 2 during driving pushes the push rod 4 downward and pushes the spool 5 so that the flow path 7 of the spool 5 pumps the port. It is opened from (P) and from this, the hydraulic actuates the traveling system to drive the traveling motor.

Since such traveling operation of the hydraulic control valve 1 is common, a detailed description thereof will be omitted.

According to the present invention, the impact return force of the return spring (9) generated when the hydraulic control valve (1) is returned to the neutral position during driving is absorbed by the hydraulic vibration preventing chamber (10) to prevent the occurrence of vibration and the like.

In other words, when the pedal 2 is operated to return to the neutral position, the pushing force of the cam 3 pushed by the pedal 2 is released from the push rod 4 and the spool 5 has the cylinder 8. The flow path 7 which has been raised by the return force of the return spring 9 imparted therein and communicated with the pump port P is cut off (the flow path 7 of the spool 5 according to the pushing operation of the pedal 2). In this case, the force of the return spring 9 of returning the spool 5 and the push rod 4 to the original state is such that the return spring 9 of the cylinder 8 extends. As the push rod 4 is pushed down from the lower end, the push rod 4 is absorbed in the hydraulic vibration preventing chamber 10 while its upward pressure acts on the push rod 4, It is to prevent the vibration that may occur when returning to the neutral position by the restoring force, which will be described in detail below. And the like.

The pushing force for pushing the push rod 4 and the spool 5 during the pushing operation of the first pedal 2 presses the cylinder 8 as shown in FIGS. 3 (a) to 3 (b) and returns the return spring. By compressing the hydraulic fluid in the cylinder 9 and the cylinder 8, the piston 13 descending together with the push rod 4 compresses the lower hydraulic vibration suppression chamber 10b so that the oil in the lower hydraulic vibration suppression chamber 10b is compressed. To the lower hydraulic vibration prevention chamber (10a) of low pressure through the orifice (18), the high pressure acts on the lower hydraulic vibration prevention chamber (10b) is a closed state.

When the pushing force of the push rod 4 is released in this driving state (that is, when it is returned to the neutral position), the pressure forcibly pushing the spool 5 is released by the restoring force of the return spring 9. The restoring force of the return spring 9 is not directly transmitted to the push rod 4 side, but the sudden elastic force of the return spring 9 generated with the decompression of the cylinder 8 is absorbed by the hydraulic vibration preventing chamber 10. It is offset and no vibration is generated.

That is, the repulsive force (ie, the restoring force) of the return spring 9 naturally raises and restores the push rod 4 as the spool 5 rises as shown in FIGS. 3 (b) to 3 (c). Ascending restoring force acting on the push rod 4 raises the piston 13 in the hydraulic vibration prevention chamber 10 together with the rise of the push rod 4, thereby compressing the upper hydraulic vibration prevention chamber 10a. The compression action of the upper hydraulic vibration prevention chamber 10a prevents the sudden rise of the push rod 4 by the return spring 9 and is caused by the lifting force of the piston 13 that compresses the upper hydraulic vibration prevention chamber 10a. The sudden elasticity of the return spring 10a is canceled here.

Looking at this in more detail; The piston 13, which rises together with the rise of the push rod 4, naturally compresses the upper hydraulic vibration prevention chamber 10a by the synergistic action thereof, so that a sudden restoration of the return spring 9 is not achieved by its compression force. This is to prevent the sudden upward action of the push rod (4) to absorb the vibration that may be caused by this, the compression of the upper hydraulic vibration prevention chamber (10a) is a high pressure in the upper hydraulic vibration prevention chamber (10a) The ball check valve 14 of the piston 13 which rises by actuation is opened, and the hydraulic pressure of the upper hydraulic vibration prevention chamber 10a under compression is sent to the lower hydraulic vibration prevention chamber 10b.

With the above action, the sudden restoring force of the return spring 9 is canceled and the push rod 4 gradually rises to come to the neutral position. The piston 13 immediately before returning to the neutral position prevents the upper and lower hydraulic vibrations. Ball check valve 14 because the upper hydraulic vibration prevention chamber 10a immediately before going to the state where the hydraulic pressure between the seals 10a and 10b is almost equal to that of the lower hydraulic vibration prevention chamber 10b. Is in a very finely open state, in this case, the oil flows from the upper hydraulic vibration prevention chamber 10a into the lower hydraulic vibration prevention chamber 10b as well.

In the state just before the neutral position, since the lower hydraulic vibration prevention chamber 10b is larger than the volume ratio of the upper hydraulic vibration prevention chamber 10a, the upper hydraulic vibration prevention chamber 10a is lower than the lower hydraulic vibration prevention chamber 10b. The same pressure as the upper hydraulic vibration prevention chamber 10 acts on the ball check valve 14 side so that the ball check valve 10a is not slightly opened by the hydraulic pressure in the high pressure state of the fine car.

This action is because the lower hydraulic vibration prevention chamber (10b) is configured to have a somewhat larger volume ratio than the upper hydraulic vibration prevention chamber (10a), even if there is an extra high pressure in the upper hydraulic vibration prevention chamber (10a) ball check valve The pressure of the lower hydraulic vibration prevention chamber 10b acting on the side 14 acts at the same pressure as the upper hydraulic vibration prevention chamber 10a so that the ball check valve 14 is closed. Is returned to the complete neutral position, the high pressure of the upper hydraulic vibration prevention chamber (10a) does not flow all the way into the lower hydraulic vibration prevention chamber (10b) through the ball check valve 14, finely remains the upper hydraulic vibration prevention chamber (10a) The high pressure of) is to be introduced into the lower hydraulic vibration prevention chamber (10b) through the orifice (18) of one side so that the return of the push rod 14 to the neutral position is made very slowly.

The reason why the volume ratio of the upper and lower hydraulic vibration prevention chambers 10a and 10b centered on the piston 13 is differently configured so that the return of the neutral position of the push rod 4 is operated very slowly as described above. If the return of the rod 4 to the neutral position does not occur slowly and merely cancels out the sudden repulsive force of the return spring 9, the shock of the sudden rebound force can be absorbed, but the push rod 4 It is intended to prevent this, and to ensure a more stable operation because there is a risk of causing vibration by compressing and operating the other push rod 4 therefrom by moving upward beyond the neutral position without returning to the neutral position.

In the above process, the leakage flow that may be caused due to the generation of high pressure in the hydraulic vibration preventing chamber 10 is discharged into the cylinder 8 (ie, the low pressure part) through the flow path 20 of the push rod 4. There is no fear of unstable operation.

As described in detail above, the present invention absorbs the vibration and shock generated from the sudden rebound force of the return spring 9 during the neutral return of the hydraulic control valve 1 between the push rod 4 and the spool 5. The piston 13 for dividing the hydraulic vibration preventing chambers 10a and 10b so as to be offset, and the ball check valve 14 and the orifice 18 are formed therein to return the neutral position of the hydraulic control valve. In order to prevent the vibration of the vehicle at the time and provide a stable operability to solve the reduction of life and safety risk of the driver, such as construction machinery, the present invention, in addition to the above-mentioned physical elastic means (shock absorption) Without the use of springs, it is possible to prevent the vibration generated when returning to the neutral position, which can expect various benefits and effects such as economic benefits.

Claims (1)

When the pedal 2 is pushed, the cam 3 arranged in the camshaft 6 in an angular motion pushes one push rod 4 and compresses the return spring 9 to operate the spool 5 downward to pump the pump. The hydraulic oil is supplied from the port P along the flow path 7 to operate the traveling system to operate the driving motor, and the spool 5 and the push rod 4 are returned by the restoring force of the return spring 9. In the hydraulic operation valve (1) in which the sudden spring restoring force of the return spring (9) is offset by the buffer means of the hydraulic vibration prevention chamber (10), the hydraulic vibration prevention chamber (10) is divided up and down. Although installed, the ball check valve 14 for conveying the hydraulic fluid in one direction is formed, the piston 13 formed integrally with the orifice 18 for communicating the hydraulic vibration prevention chamber 10 divided up and down to move the hydraulic fluid ) And the push rod 4 formed at a predetermined diameter on the upper and lower portions of the piston 13 are the pieces. (13) and the reciprocating operation in the hydraulic vibration prevention chamber 10, the upper push rod diameter (L ') is formed larger than the lower push rod diameter (L), the upper hydraulic vibration prevention chamber (10a) during the reciprocating operation ) And the lower hydraulic actuating chamber (10b) is changed in volume depending on the diameter (L ', L) of the push rod (4).