JPS6018602A - Brake valve - Google Patents

Abstract

PURPOSE:To prevent the ocurrence of abnormal surge pressure in time of a relief valve being close, by installing a spring-energized poppet valve body in a hydraulic chamber being open to a hydraulic source oil passage and an actuator side oil passage, while interconnecting the hydraulic chamber to the actuator side oil passage via a throttle. CONSTITUTION:When oil is fed to an oil passage 14A, if a directional control valve (selector) is set to a neutral position, a counterbalance valve 7 comes in neutral as well, and thereby surge pressure is produced in both oil passages 12B and 25B at the actuator side but since a hydraulic chamber 42B is interconnected to the oil passage 25B via a throttle 46B, it will not follow up immediately and, with a pressure differential, a poppet valve body 43B is set in motion against a spring 45B, causing the pressure inside the oil passage 25B to be relieved to a hydraulic source oil passage 24B, thus the surge pressure is reduced to some extent. The pressure of the hydraulic chamber 42B is raised up, closing a valve seat 30B. When the pressure is further boosted up, a relief valve 48B operates. If check valves 41A and 41B are installed, both poppet valves 43A and 43B are yet favorably opened-very good for reducing the surge pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake valve installed in, for example, a hydraulic circuit that drives an inertial body using a hydraulic motor.

FIGS. 1 and 2 show brake valves installed in hydraulic circuits that have conventionally been commonly used to drive construction machines as inertial bodies.

In the figure, reference numeral 1 denotes a hydraulic motor that drives an inertial body 2, and the hydraulic motor 1 is provided with a pair of supply/discharge ports (A, B).

B are each connected to a directional control valve 4 via a brake valve 3. Each supply/discharge port (A, B) of the hydraulic motor 1 is connected to a hydraulic pump 5 as a hydraulic pressure source by the directional switching valve 4.
and tank 6 in a switchable manner.

Here, the brake valve 3 interposed between the hydraulic motor 1 and the directional switching valve 4 includes a counterbalance valve 7, a pair of check valves 8A, 8B, a pair of IJ, IJ-F valves 9A,
9B, and each of these members is a casing 1.
It is set within 0. To this end, the casing 10 is provided with oil passages 12. to 11A, 11B having one end connected to each port A, H of the hydraulic motor 1, and the other end of the pipes 11A, 11B. A
, 12B, a pipe 13A whose one end is connected to the directional switching valve 4, an oil passage 14A to which the other end of 13B is connected,
14B is formed. And each oil passage 12A;
x 2B opens to oil chambers 15A and 15B, and also opens to oil passage 1.
4A.

14B opens into oil chambers 16A and 16B. moreover,
The spool 1 of the counterbalance valve 7 is installed in the casing 10.
7 is slidably inserted into the spool 17, and an oil chamber 15 is inserted into the spool 17.
A land 17A is provided for communicating and blocking communication between A and 16A, and an oil chamber 15B.

A land 17B is provided that communicates and blocks communication between the areas 16B. The spool 17 has both ends connected to the casing 1.
Pilot chamber 18A formed at 0.

1.8B, and inside each pilot chamber 18A, 18B is a damper member 19A that comes into contact with each end surface of the spool 17.
, 19B are installed. Each Dan/Ya member 19A
, 19B and the caps 20A and 20'B that close the pilot chambers 18A and 18B.
7. Spring 21A for returning to the neutral position.

21B is interposed. Also, oil chamber 16A.

16B and the pilot chambers 18A and 18B are communicated through oil passages 22A and 22B provided in the spool 17, respectively, and the damper members 19A and 19B are provided with throttle passages 23A and 23B, respectively (the throttle passage 23A is shown in the drawing). (not shown above) is drilled.

Next, 24A and 24B are oil chambers 16A, respectively.

Oil passages communicating with 16B, 25A and 25B are oil passages 12A,
12B, each oil passage 24A is shown.
, Question 25A and Oil Road 24B.

Check valves 8A and 8B are respectively interposed between 25B, and the check valves 8A and 8B are oil passages 24A.

O-check valves 8A and 8B, which are designed to allow pressure oil to flow only from the 24B side toward the oil passages 25A and 25B, are formed in the casing 10 so as to open into the oil passages 25A and 25B, respectively. Hydraulic chambers 26A and 26B
and poppet valve bodies 27A, 27B slidably extended and lowered into the respective hydraulic chambers 26A, 26B, and the respective poppet valve bodies 27.
A, 27B and hydraulic chambers 26A, 26Bf: Springs 29A, 29 interposed between the closing characters 7' 28A, 28B
B and the poppet valve bodies 27A and 27B are the oil passages 24.
Valve seats 30A and 30BfCPrm formed around the openings of oil passages A and 24B to oil passages 25A and 25B can be seated thereon. And piping 11A, 13
A.

Oil passages 12A, 14A, 24A, 25A, oil chamber 15
A.

16A forms an oil passage 31A connected to m ports A of the hydraulic motor 1, and pipes 11B and 13B.

Oil passages 12B, 14B, 24B, 25B, oil chamber 15B.

16B forms an oil passage 31B that is connected to the other port B of the hydraulic motor 1. Here, each oil passage 31A
, 31B is a valve seat 30A; 30B is a poppet valve body 27A
, 27B are seated, the parts on the actuator side from the oil passages 25A and 25B form an actuator side oil passage, and the oil passage 24A.

The part on the hydraulic source side from 24B is the hydraulic source side oil path. The poppet valve bodies 27A and 27B are provided with an oil passage 25A that constitutes an actuator side oil passage.

Oil holes 32A and 32B are drilled to allow constant communication between 25B and the hydraulic chambers 26A and 26B. As a result, the pressure in the oil passages 24A and 24B and the oil passage 25A.

25B, the poppet valve bodies 27A, 27B resist the springs 29A, 29B and push against the valve seat 30.
Separated from A' and 30B, oil passage 24A.

The pressure oil in 24B can flow in the direction of oil passages 25A and 25B.

Furthermore, between the oil passages 12A and 12B, there is a pair of oil passages 33A and 3.
3B, each oil passage 3'3A,
Relief valves 9A and 9B are interposed in the middle of 33B. Each of the relief valves 9A and 9B has a spring 34A.
, 34B, each forming a part of the oil passage on the actuator side.
When the pressure in 2A and 12B exceeds this IJ iJ-F set pressure, the oil passage 12B, which is the oil passage on the other side of the actuator,
, 12A can be flown with pressure oil.

The IJ valve according to the prior art has the above-mentioned structure, and its operation will now be described.

Now, assume that the directional switching valve 4 is switched from the neutral position to, for example, the switching position on the left in the figure. This allows the hydraulic pressure, I
? The pump is connected to pipe 13A and also to pipe 13. B is connected to tank 6. For this reason, the pressure oil supplied from the hydraulic train pump 5 flows into the oil passage 14A through the pipe 13A, and the pressure inside the oil chamber 16A becomes high. This pressure acts on the port valve body 27A via the oil passage 24A, and
A, month due to the differential pressure between 25A? The pet valve body 27A is separated from the valve seat 30A. Therefore, the oil passages 24A and 25A communicate with each other, and the pressure oil from the hydraulic pump 5 forms the oil passage 14A, the oil chamber 16A, and the oil passage 24A.

258, 1.2A1 pipe 11A, and is supplied to sr-h of the hydraulic motor 1 in sequence. At the same time, oil chamber 16
The pressure oil in A is also supplied to the pilot chamber 18A through the oil passage 22A, and the pilot chambers 18'A, 181
A differential pressure occurs between the two. For this reason, the spool 17 is displaced to the right in the figure against the spring 21B, and the oil chamber 1511 and the oil chamber 16B are communicated with each other. Therefore, port B of hydraulic motor 1
are the piping 11B and the oil passage 12 forming the oil passage 31B on the other side.
B, the directional control valve 4 is switched to the state where it is connected to the tank 6 via the oil chambers 15B, 16B, oil passage 14B, and piping 13B in this order. In this way, high pressure hydraulic oil is supplied from the hydraulic pump 5 to the port A of the hydraulic motor 1.
The return oil discharged from port B is returned to tank 6. Then, the inertial body 2 is driven by the hydraulic motor 1.
is driven.

Next, when the directional control valve 4 is returned to the neutral position to stop driving the inertial body 2, the hydraulic pump 5 and the oil poppet valve body 2
7A is seated on the valve seat 30A by the action of the spring 29A, and communication between the oil passage 24A and the oil passage 25A is cut off. In addition, the pressure inside the pilot chamber 18A also decreases,
The spool 17 of the counter lance valve 7 returns to the neutral position, and communication between the oil chamber 15B and the oil chamber 16B is also cut off.

At this time, if the inertial force of the inertial body 2 is acting on the hydraulic motor 1, the hydraulic motor 1 is forcibly driven to rotate and J?
It works as a pump and sucks in hydraulic oil from port A and discharges it to port B. However, since the check valve 8B is in the closed state and the spool 17 of the counterbalance valve 7 is in the circuit closed state by blocking the oil chambers 15B and 16B, y+? - The high-pressure hydraulic oil discharged from port B is not discharged to the outside. For this reason, piping 11
B and oil passage 12B become high pressure, and this pressure
3B'r acts on the relief valve 9B, and when the relief setting pressure is exceeded, the relief valve 9B is opened, and the hydraulic oil in the oil passage 12'B flows into the oil passage 12A, causing the hydraulic motor 1, A closed circuit consisting of piping 11B1 oil passage 12B1 oil passage 33B1 relief valve 9B, oil passage 12A1 piping 11A is formed, and the inertial energy of the inertial body 2 is transferred to the hydraulic motor 1.
The high-pressure hydraulic oil discharged from N-)B is converted into thermal energy generated when it passes through the IJ-IJ-F valve 9B, and as a result, a braking action against the inertial body 2 is exerted.

Contrary to the above, when the directional control valve 4 is switched to the left switching position in the figure, high pressure hydraulic oil is supplied to the port B of the hydraulic motor 1, and the hydraulic motor 1 is moved in the opposite direction to that described above. Rotationally driven. When the directional control valve 4 is returned to the neutral position from this state, the relief valve 9A is activated and the braking action of the inertial body 2 is performed in the same manner as described above.

The brake valve 3 is activated as described above, but there is generally a delay in activation of the IJ-IJ valve.

For this reason, for example, when the directional control valve 4 is returned to the neutral position from the switching position on the left in the figure, the counterbalance valve 17 also immediately returns to the neutral position, and at this time, due to the delay in operation of the relief valve 9B, As a result, surge pressure is generated in the oil passage 12B1 piping 11B, which is the actuator side oil passage.

Since this surge pressure increases in accordance with the flow rate, when the hydraulic motor 1 is driven to rotate at high speed and a large flow of hydraulic oil flows in the circuit, the surge pressure generated when the relief valve 9B is activated is also extremely large. Become something. Here, in the brake valves according to the prior art described above, the relief valves 9A, 943
Since only the IJ function is exerted, the above-mentioned surge pressure may not be absorbed efficiently. For this purpose, piping 11B1 oil passage 12B or piping 11A, oil passage 12, which is the discharge side of hydraulic motor 1.
There was a drawback that a momentary but extremely large back pressure was generated on the A side, causing damage to the various components constituting the hydraulic motor 1 and the brake valve 3.

The present invention has been made in order to eliminate the drawbacks of the prior art described above, and it prevents abnormal surge pressure from occurring in the circuit when the relief valve is opened, and thereby prevents the occurrence of abnormal surge pressure in the circuit. The object of the present invention is to provide a brake valve that can effectively protect equipment.

In order to achieve the above-mentioned object, the brake valve according to the present invention includes a hydraulic chamber formed in a casing in which a pair of oil passages connecting an actuator and a hydraulic pressure source are formed, and a hydraulic chamber opened to each of the oil passages; A poppet valve element slidably inserted into each hydraulic chamber and each poppet valve element are separated and seated, thereby defining each oil passage into an oil passage on the hydraulic power source side and an oil passage on the actuator side. A throttle passage is formed by a valve seat and a spring that biases each of the poppet valve elements in the valve closing direction, and connects each of the hydraulic chambers with the oil passage on the actuator side, and is connected to the oil passage on the other side. The feature is that a relief valve is provided between the actuator side oil passage and the actuator side oil passage.

Hereinafter, the present invention will be described in detail based on the drawings.

First, FIG. 3 does not show the first embodiment of the present invention. However, 41A and 41B are oil passages 24A, respectively.

25A and between oil passages 24B and 25B, each check valve 41a, 41i3 is connected to oil passage 2
Hydraulic chambers 42A, 42B formed in casing 10 so as to open into 5A, 25B.
Poppet valve bodies 43A and 43B are slidably installed inside the
The poppet valve body 43A.

43B, and a cap 4 that covers the hydraulic chambers 42A and 42B.
Spring 45A interposed between 4A and 44B.

45B, and each of the l-bed valve bodies 43A, 43B.

Valve seat 30A13 is normally held by springs 45A and 45B.
0B is seated. The high-pressure hydraulic oil is configured to be able to flow out from the oil passage 24B side toward the oil passages 25p, , 2'5B.

Here, the diameter Ll of the poppet valve bodies 43A, 43B is larger than the diameter L2 of the valve seats 30A, 30B, and therefore the poppet valve body 43A.

The side of 43B that comes into contact with the valve seats 30A and 30B is the valve seat 30A.
, 30B, the inner circumferential side of which forms the oil pressure source side oil path 24A.
, 24B acts as a receiving surface on the hydraulic source side. On the other hand, an oil passage 25A forming an actuator side oil passage is provided on the outer peripheral side of the valve seats 30A and 30B.

It serves as the actuator side pressure receiving surface on which the pressure inside 25B acts. Further, an oil passage 25A constitutes an actuator side oil passage with the hydraulic chamber 42at42B.

25B, a poppet valve body 43A,
The oil holes drilled in 43B are one or more restriction holes 46A and 46B.

Also, hydraulic chambers 42A, 42B and oil passage 12B.

12A is connected to multiple oil passages 47A and 478, and a relief valve 48 is provided in the middle of each oil passage 47A and 47B.
A#48B is interposed. Each relief valve 48A,
48B is each spring 49A.

49B has a predetermined relief setting pressure.

When the inside of the oil passage 12A exceeds the relief setting pressure, it acts on the oil passage 47A through the oil passage 25A, the restriction hole 46A, and the hydraulic chamber 42A, opens the relief valve 48A, and activates the actuator in the oil passage 31B on the other side. Oil passage 1 constituting the side oil passage
2BK')') On the contrary, when the inside of the oil passage 12B becomes equal to or higher than the relief setting pressure, the oil passage 31 on the other side
Oil passage 12AICI that borrows the actuator side oil passage of A
The structure is such that it can have 7 leaves.

The brake valve configured as described above has its oil passages 12A and 12B connected to the pipe 11A, as in the prior art.
, IIB, and is connected to the oil passage 14A.

14B is connected to the pipes 13A and 13B, and the hydraulic motor 1
A part of the drive circuit of the inertial body 2 using the structure is connected to the hydraulic bonder 5, high pressure hydraulic oil is supplied to the port A side of the hydraulic motor 1, and the hydraulic motor 1 is driven to rotate at high speed. The directional control valve 4 is closed when a large flow of hydraulic oil is flowing in the circuit.
Suppose that it returns to the neutral position. Even if the directional control valve 4 is returned to the neutral position in this way, the hydraulic motor 1 is forcibly rotated by the inertial force of the inertial body 2, but the counterbalance valve 7 does not return the directional control valve 4 to the neutral position. Following the return, it returns to the neutral position, and oil passage 12B and oil passage 1.4B
Communication between the two is abruptly cut off. For this reason, the inside of the piping 11B1 oil passage 12B, which is the discharge side of the hydraulic motor 1, becomes abnormally high pressure and a surge pressure is generated. This pressure also acts within the oil passage 25B. By the way, the hydraulic chamber 42B
is in communication with the oil passage 25B through the restriction hole 46Bffi, so even if the pressure in the oil passage 25B increases, the hydraulic chamber 42B does not immediately follow this and cause the pressure to rise. For this reason, a pressure difference is generated between the oil passage 25B and the hydraulic chamber 42B. Then, the pressure in the oil passage 25B acts on the outer circumferential side of the contact portion of the poppet valve body 43B with the valve seat 30B,
The poppet valve body 43B compresses the hydraulic oil in the hydraulic chamber 42B, moves away from the valve seat 30B, and relieves the pressure in the oil passage 25B to the oil passage 24B. Therefore, the surge pressure generated when the circuit is closed is reduced, and problems such as damage to equipment in the circuit are prevented.

Although it is through the restriction hole 46B, the oil passage 25B
Since the hydraulic chamber 42B and the hydraulic chamber 42B are in communication with each other, the pressure of the hydraulic chamber 42B becomes equal to that of the oil passage 25B. Therefore, the poppet valve body 43B is seated on the valve seat 30+1 by the action of the spring 45B, and communication between the oil passage 25B and the oil passage 24B is again cut off. However, since the hydraulic motor 1 is rotationally driven by the inertial body 2, the hydraulic motor 1 performs a pumping action, and the pressure in the pipe 11B1 oil passage 12B increases in proportion to the discharge flow rate. This pressure is applied to the oil passage 47 via the oil passage 25B, the restriction hole 46B1, and the hydraulic chamber 42B.
When this pressure exceeds the relief setting pressure of the relief valve 48B, the relief valve 48B opens, and this pressure is relieved to the oil passage on the other side. , the inertial energy of the inertial body 2 is absorbed, and the inertial body 2 is braked.

On the other hand, when the oil passage 14B returns to the neutral position from the state where it is connected to the hydraulic pump 5, the check valve 4
]A1 relief valve 48A is activated.

Next, FIG. 4 shows a second embodiment of the present invention, and in this figure, the same components as in FIG. 3 are given the same reference numerals, and their explanations will be omitted.

However, in this embodiment, the hydraulic chambers 42A, 42B and the oil passage 12
A and 12B are connected with oil passages 51A and 51B, respectively,
Hydraulic chambers 42A, 42 are provided in the middle of each oil passage 51A, 51B.
A check valve 52A that allows hydraulic oil to flow only from the B side toward the oil passages 12A and 12B.

52B is interposed therebetween.

By adopting such a configuration, the oil passage 14A or the oil passage 14B is connected to the hydraulic pump 5, and the poppet valve bodies 43A, 43B forming the check valves 41A, 41Bi
When the pressure of the hydraulic pump 5 acts on the hydraulic chamber 42
The hydraulic oil in A and 42B flows from the restriction holes 46A and 46B to the oil passage 25A.

2.5 Check valve 52A while being discharged to B.

Open the valve 52B and from the oil passages 51A and 51B to the oil passage 12A,
Since it will also flow out to 12B, check valve 41A
, 41B have better responsiveness.

On the other hand, the oil pressure chamber 42A is connected to the oil passages 12A and 12B.

Since the hydraulic oil does not flow backward toward 42B, there is no problem with the effect of reducing the air pressure.

In each of the above-mentioned embodiments, the explanation was given as being provided in a hydraulic circuit used in a traveling device of a construction machine, but the essence is a hydraulic circuit that drives an inertial body, and absorbs the inertial energy of the inertial body when the drive is stopped. If it is necessary to perform a braking operation using the oil passages 31A and 31B, which can be used for purposes other than the travel drive circuit of the construction machine described above, the oil passages 31A and 31B may be provided so as to communicate with the actuator side portion. If it is, it is not necessarily necessary to drill into the poppet valve bodies 43A and 43B, and for example, one end of the casing 10 is connected to the hydraulic pressure.
42A, 42B, and the other end may be configured to open to the oil passages 25A, 25B or the channel passages 12A, 12B.

As explained above, the brake valve according to the present invention is configured so that the check valve that allows hydraulic fluid to flow from the hydraulic source side to the actuator side has a relief function that reduces surge pressure. It is possible to prevent the generation of surge pressure and protect equipment such as the hydraulic motor and brake valve that constitute the circuit from being damaged.

[Brief Description of the Drawings] Fig. 1 and Fig. 2 show the prior art, Fig. 1 is a hydraulic circuit diagram, Fig. 2 is a vertical sectional view of a brake valve, and Fig. 3 is a diagram of a brake valve according to the present invention. Vertical sectional view showing the first embodiment, the fourth
The figure is a longitudinal sectional view of a brake valve showing a second embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Hydraulic motor, 5...Hydraulic pump, 7...Counter balance valve, 10...Casing, 12A, 1
2B. 14A, 14B, 24A, 24B, 25A, 25B. 47A, 47B, 51A, 51B...oil passage, 17...
- Spool, 31A, 31B...Oil passage, 41A. 41B...Check valve, 42A, 42B...Hydraulic chamber, 43A, 43B...Poppet valve body, 45A, 45B
...Spring, 46A, 46B...Aperture hole, 48A, 4
8B...Relief valve, 52A, 52B...Check valve Fig. 1

Claims (2)

[Claims] (1) A pair of oil passages are formed in the casing, one end of which is connected to each supply/discharge passage of the actuator, and the other end of which is switchably connected to a hydraulic power source, and a counterbalance valve is installed in the middle of each oil passage. and a pair of check valves that allow hydraulic fluid to flow from the hydraulic pressure source side toward the actuator side, the brake valve having a hydraulic chamber formed in the casing so as to open to each of the oil passages; , the poppet valve body slidably inserted into each hydraulic chamber and the bottom hard valve body come into contact with each other, thereby converting each oil passage into an oil passage on the hydraulic power source side and an oil passage on the actuator side. and a spring that biases each of the qQ and dt valve elements in the valve closing direction, and provides nine restrictor passages that communicate each of the hydraulic chambers with the actuator side oil passages, Each of the oil passages and others (1i
1. A brake valve characterized in that a relief valve is provided between the actuator side oil passage and the actuator side oil passage. (2) Each of the oil chambers and the actuator side oil passage are connected via a check valve that allows hydraulic oil to flow only from each oil pressure chamber to each actuator side oil passage. Brake valve described in scope (1).