JPH0419203Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a brake valve provided in a hydraulic circuit or the like that drives an inertial body using, for example, a hydraulic motor.

[Prior art]

FIGS. 3 to 5 show hydraulic circuits and brake valves that have conventionally been commonly used to drive construction machinery as an inertial body.

In the figure, 1 indicates a hydraulic motor as an actuator that drives an inertial body 2. The hydraulic motor 1 is provided with a pair of supply/discharge ports A, B, and each supply/discharge port A, B has a brake. It is connected to a directional control valve 4 via a valve 3. The directional switching valve 4 connects each supply/discharge port A, B of the hydraulic motor 1 to a hydraulic pump 5 and a tank 6 as hydraulic power sources in a switchable manner.

Here, the brake valve 3 interposed between the hydraulic motor 1 and the directional switching valve 4 is a counterbalance valve 7.
, a pair of check valves 8A, 8B, and a pair of relief valves 9A, 9B, and each of these members is provided within the casing 10. For this purpose, the casing 10 has piping 11A, 11 connected at one end to each port A, B of the hydraulic motor 1.
Oil passages 12A and 12B to which the other end of B is connected, and piping 13A13B to which one end is connected to the directional control valve 4
Oil passages 14A and 14B are formed to which the other ends are connected. The respective oil passages 12A, 12B open to oil chambers 15A, 15B, and the oil passages 14A, 1
4B opens into oil chambers 16A and 16B. Furthermore, a spool 17 of the counterbalance valve 7 is slidably fitted into the casing 10, and the spool 17 is provided with a land 17A that communicates and blocks the oil chambers 15A and 16A.
A land 17B is provided that communicates and blocks communication between B and B. The spool 17 has both ends connected to pilot chambers 18A and 1 formed in the casing 10.
8B, damper members 19A and 19B which come into contact with each end surface of the spool 17 are disposed in the respective pilot chambers 18A and 18B. The damper members 19A, 19B and the pilot chambers 18A, 18B
Between the caps 20A and 20B that close the spool 17, there is a spring 21A for returning the spool 17 to the neutral position.
21B is interposed. In addition, the oil chamber 16A, 1
6B and the pilot chambers 18A, 18B are communicated by oil passages 22A, 22B provided in the spool 17, respectively, and the damper members 19A, 19B are provided with throttle passages 23A, 23B (throttle passage 2), respectively.
3A (not shown in the drawing) is drilled.

Next, 24A and 24B are oil chambers 16A and 24B, respectively.
Oil passage communicating with 16B, 25A and 25B are oil passage 1
2A and 12B are shown, and between the oil passages 24A and 25A and between the oil passages 24B and 25.
Check valves 8A and 8B are interposed between the oil passages 24A and 24B, respectively.
The pressure oil can be allowed to flow only from the B side toward the oil passages 25A and 25B. Check valves 8A and 8B are connected to oil passages 25A and 25, respectively.
Hydraulic chambers 26A, 26B formed in the casing 10 so as to open into B, and the respective hydraulic chambers 26A, 2
Poppet valve body 27 slidably inserted into 6B
A, 27B and each poppet valve body 27A, 27B
and a cap 28 that closes the hydraulic chambers 26A and 26B.
Spring 29A, 29B interposed between A, 28B
The poppet valve bodies 27A, 27B can be moved into and out of valve seats 30A, 30B formed around the openings of the oil passages 24A, 24B to the oil passages 25A, 25B. And oil road 1
2A, 14A, 24A, 25A, oil chamber 15A, 1
Piping 1 is connected to port A on one side of hydraulic motor 1 by 6A.
1A is formed, and an oil passage 31B is connected to the other side port B of the hydraulic motor 1 via piping 11B by oil passages 12B, 14B, 24B, 25B, and oil chambers 15B, 16B.
is formed. Here, each oil passage 31A, 31
B has a poppet valve body 27A on the valve seats 30A and 30B,
When 27B is seated, oil passages 25A and 25
A portion on the actuator side from B forms an actuator side oil passage, and a portion on the oil pressure source side from the oil passages 24A and 24B forms a hydraulic source side oil passage. and,
The poppet valve bodies 27A and 27B are provided with oil passages 25A and 25B that constitute actuator side oil passages and a hydraulic chamber 2.
Oil holes 32A, 3 that constantly communicate with 6A, 26B
2B is drilled. As a result, the oil passage 24
When a pressure difference occurs between the pressure in A and 24B and the pressure in oil passages 25A and 25B, the poppet valve body 27
A, 27B are the valve seats 3 against the springs 29A, 29B.
They are separated from 0A and 30B so that the pressure oil in oil passages 24A and 24B can flow toward oil passages 25A and 25B.

Furthermore, a pair of oil passages 3 is provided between the oil passages 12A and 12B.
3A and 33B, each oil passage 3
Relief valves 9A, 9B are interposed in the middle of 3A, 33B. Each of the relief valves 9A, 9B has a predetermined relief setting pressure given by a spring 34A, 34B, respectively, and the pressure in each oil passage 12A, 12B, which forms a part of the oil passage on the actuator side, reaches this relief setting pressure. When it is crossed, pressure oil can flow toward the oil passages 12B and 12A, which are the actuator side oil passages on the other side.

The brake valve 3 according to the prior art has the above-mentioned configuration, and its operation will be explained next.

Now, suppose that the directional switching valve 4 is switched from the neutral position to the switching position on the left side in the figure, for example, so that the hydraulic pump 5 is connected to the pipe 13A, and the pipe 13B is connected to the tank 6. For this purpose, the pressure oil supplied from the hydraulic pump 5 is
3A into the oil passage 14A, and enters the oil chamber 16A.
High pressure inside. This pressure acts on the poppet valve body 27A through the oil passage 24A, and the oil passage 24A25A
Due to the differential pressure between the poppet valve body 27A and the valve seat 30A,
Leave the seat. Therefore, the oil passages 24A and 25A communicate with each other, and the pressure oil from the hydraulic pump 5 is transferred to the oil passage 31.
Oil passage 14A, oil chamber 16A, oil passage 24 forming A
It is supplied to port A of the hydraulic motor 1 via A, 25A, 12A, and piping 11A in sequence. At the same time, the pressure oil in the oil chamber 16A is also supplied to the pilot chamber 18A via the oil passage 22A, creating a pressure difference between the pilot chambers 18A and 18B. For this reason, the spool 17 is displaced to the right in the figure against the spring 21B, and the oil chamber 15B and the oil chamber 16B communicate with each other. Therefore, port B of the hydraulic motor 1 is connected to the pipe 11
B and the oil passage 12 forming the other side oil passage 31B
The directional control valve 4 is connected to the tank 6 via the oil chambers 15B and 16B, the oil passage 14B, and the piping 13B in this order. In this way, high-pressure hydraulic oil is supplied from the hydraulic pump 5 to port A of the hydraulic motor 1 to rotate the hydraulic motor 1 in one direction, and return oil discharged from port B is returned to the tank 6. . Then, the inertial body 2 is driven by the hydraulic motor 1.

Next, when the directional control valve 4 is returned to the neutral position to stop driving the inertial body 2, the connection between the hydraulic pump 5 and the oil passage 14A is cut off, and the supply of pressure oil to the oil passage 14A is interrupted. will be stopped. Therefore, the poppet valve body 27A of the check valve 8A is seated on the valve seat 30A by the action of the spring 29A, and the oil passage 24A is seated on the valve seat 30A.
Communication between the oil passage 25A and the oil passage 25A is cut off. Also,
The pressure in the pilot chamber 18A also decreases, the spool 17 of the counterbalance 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, when the inertial force of the inertial body 2 acts on the hydraulic motor 1, the hydraulic motor 1 is forcibly driven to rotate and exerts a pumping action, and the port A
It sucks in hydraulic oil from the port and discharges it to the port B side. However, the check valve 8B is in a closed state, and the spool 17 of the counterbalance valve 7 is in the oil chamber 15.
Since the circuit is closed by cutting off between B and 16B, the high pressure hydraulic oil discharged from port B will not be discharged to the outside. For this reason, the inside of the pipe 11B and the oil passage 12B becomes high pressure, and this pressure acts on the relief valve 9B via the oil passage 33B, and when it exceeds the relief setting pressure, the relief valve 9B
is opened, the hydraulic oil in the oil passage 12B flows into the oil passage 12A, and the hydraulic motor 1, the piping 11B,
A closed circuit consisting of oil passage 12B, oil passage 33B, relief valve 9B, oil passage 12A, and piping 11A is formed,
The inertial energy of the inertial body 2 is converted into thermal energy generated when the high-pressure hydraulic oil discharged from port B of the hydraulic motor 1 passes through the relief valve 9B, and as a result, the braking action on the inertial body 2 is reduced. Demonstrated.

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

[Problem that the invention attempts to solve]

By the way, in the prior art having the above configuration, when a construction machine (for example, a hydraulic excavator or a hydraulic bulldozer) is used for excavating a slope, leveling work, etc., the construction machine performs the work while climbing and descending the slope. It turns out.

Therefore, when the directional control valve 4 is suddenly switched over the neutral position, for example from the right switching position to the left switching position, the rotation of the hydraulic motor 1 is switched from the other direction to the one direction. At the same time, the poppet valve body 27B of the check valve 8B comes to be seated on the valve seat 30B by the biasing force of the spring 29B.

However, if the inertial force of the hydraulic motor 1 and the inertial body 2 is very small (for example, when a construction machine moves from a climbing direction to a descending direction, or when the crawler is jerked up to remove mud from a crawler show, there is a sudden reversal of forward and backward movement). As a transient phenomenon, the hydraulic oil flowing through the check valve 8B flows through the oil passage 25B as shown in FIG.
The oil immediately flows in the direction of arrow C from the oil passage 24B to the oil passage 24B, and the flow rate increases rapidly thereafter.

On the other hand, in the check valve shown in FIG. 5, when the hydraulic oil flows from the oil passage 24B to the oil passage 25B, a fluid force acts on the poppet valve body 27B in the direction of closing the valve, and the hydraulic oil flows from the oil passage 25B to the oil passage 24B. It is generally known that when hydraulic oil flows, a fluid force acts on the poppet valve body 27B in the direction shown by arrow F to open the poppet valve body 27B.

When the directional control valve 4 is suddenly switched from the right switching position to the left switching position as described above, if the inertial force is small, the poppet valve body 27B will be pushed against the valve seat. 30B, the motor rotates in reverse, causing a flow in the direction of arrow C from oil passage 25B to oil passage 24B as shown in FIG. 5, and the flow in the direction of arrow C is caused by fluid force. F, which acts in the valve opening direction. As a result, the fluid force F is the biasing force of the spring 29B and the hydraulic chamber 26
This temporarily balances the hydraulic pressure in B, and the seating of the poppet valve body 27B on the valve seat 30B is delayed.

Therefore, in the prior art, the flow rate of the hydraulic oil from the hydraulic motor 1 increases rapidly after that, and the oil passage 12
When the amount of oil flowing through B, 25B increases, the equilibrium state due to the fluid force F is lost, and the poppet valve body 27B suddenly comes to sit on the valve seat 30B. Therefore, the poppet valve body 27B is suddenly shut off when the flow rate of the oil flowing in the direction of arrow C increases, so that the oil passage 25
Surge pressure is generated in B, 12B, and brake valve 3
This has the disadvantage that the hydraulic motor 1 and the like are damaged.

The present invention was devised in view of the above-mentioned drawbacks of the prior art, and the present invention provides a check valve closing operation, that is, the time required for the poppet valve body to sit on the valve seat, when the rotation direction of the hydraulic motor is reversed. It is an object of the present invention to provide a brake valve which can improve the responsiveness of the check valve so as not to cause a delay, and which can prevent the generation of surge pressure.

[Means for solving problems]

The feature of the configuration adopted by the present invention in order to solve the above-mentioned problems is that each check valve provided in the middle of a pair of oil passages arranged in the casing is
a valve seat provided in the middle of each of the oil passages; a hydraulic chamber provided in the casing so as to be located closer to the oil pressure source side than the valve seat and open opposite the valve seat; a poppet valve body that is slidably inserted into the hydraulic chamber and separates and seats on the valve seat to define each of the oil passages into a hydraulic power source side oil passage and an actuator side oil passage, and the poppet valve body comprises a spring that biases the valve body toward the valve seat, and a communication passage that permanently communicates the hydraulic chamber with the actuator side oil passage, and the poppet valve body receives pressure from the oil pressure source side oil passage. A pressure-receiving surface is formed that acts from the outside in the radial direction of the valve seat to cause the poppet valve element to open against the spring.

[Effect]

With the above configuration, for example, even if the directional control valve is switched in one direction and the poppet valve element of the check valve is opened by pressure from the oil passage on the oil pressure source side, the directional control valve is suddenly switched in the other direction. At this time, the flow of pressure oil from the actuator side oil passage can apply a fluid force in the valve closing direction to the poppet valve element, and the poppet valve element can be immediately opened.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. In the embodiment, the same components as those of the prior art shown in FIGS. 3 to 5 described above are given the same reference numerals, and the explanation thereof will be omitted.

In the figure, 41A and 41B are oil chamber 1, respectively.
Oil passages 6A and 16B communicate with each other, and 42A and 42B are oil passages that communicate with oil passages 12A and 12B, respectively.
The respective oil passages 42A, 42B are the oil passages 41A, 41
They are formed in the casing 10 so as to be orthogonal to B, respectively. Thus, in this embodiment, oil path 1
2A, 42A, 41A, oil chambers 15A, 16A, and oil passage 14A form one oil passage 31A, and the other oil passage 31A is formed by oil passages 12B, 42B, 41B, oil chambers 15B, 16B, and oil passage 14B. An oil passage 31B (see FIG. 3) is formed.

43A and 43B are oil passages 42A and 42, respectively.
The valve seats 44A and 44B formed on the periphery of the openings to the respective oil passages 41A and 41B of B are the respective valve seats 4.
The casing 1 faces 3A and 43B.
0, each hydraulic chamber 44A, 44
B is located closer to the oil pressure source side than each valve seat 43A, 43B, and opens perpendicularly to each oil passage 41A, 41B, respectively. 45A, 45
Reference numeral B designates a cap that removably covers the base end side of each of the hydraulic chambers 44A, 44B.

46A and 46B are the hydraulic chambers 44, respectively.
A, 44B so as to be slidably inserted therein and seated on and off the respective valve seats 43A, 43B, thereby defining each of the oil passages 31A, 31B into a hydraulic oil passage and an actuator side oil passage. Each poppet valve body 46A, 46B has a tapered surface on the bottom side, and each oil passage 41A, 46B has a tapered surface.
Each poppet valve body 46A, 46 is opened by hydraulic pressure of 41B.
Pressure receiving surfaces 47A and 47B for opening the valve B are respectively formed. 48A and 48B are the poppet valve bodies 46A and 46B and the caps 45, respectively.
A, 45B, each poppet valve body 4
The springs 49A and 49B biasing the valves 6A and 46B toward the respective valve seats 43A and 43B are communication passages bored in the axial direction at the bottoms of the respective poppet valve bodies 46A and 46B (however, the communication passages are not shown in the figure). (The passage 49A is omitted), and the respective communication passages 49A and 49B permanently communicate the respective hydraulic chambers 44A and 44B with the respective actuator side oil passages, for example, the respective oil passages 42A and 42B.

Thus, in this embodiment, the check valve 8A has the valve seat 43A, the hydraulic chamber 44A, the poppet valve body 46A, the spring 48A, and the communication passage 49A, and the check valve 8B has the valve seat 43B, the hydraulic chamber 44B, the poppet valve body 46B, Each of them is composed of a spring 48B and a communication path 49B.

Next, the operation of the brake valve configured as described above will be explained.

The brake valve is also connected to each oil passage 12 as in the prior art.
A, 12B are connected to each port A, B of the hydraulic motor 1 via piping 11A, 11B, respectively, and each oil passage 14A, 14B is connected to piping 13A, 13B, respectively.
The directional control valve 4 is connected to a hydraulic pump 5 and a tank 6 (see FIG. 3). When the directional control valve 4 is switched from the neutral position to the left switching position in FIG. 3, from the left switching position to the neutral position, or from the neutral position to the right switching position, the above-mentioned conventional technique It works almost the same way.

On the other hand, when the directional control valve 4 is switched over the neutral position, for example from the right switching position to the left switching position, the hydraulic motor 1 and the inertial body 2
When the inertial force of the hydraulic motor 1 is very small, the rotation direction of the hydraulic motor 1 is reversed before the poppet valve body 46B closes, and the direction of rotation of the hydraulic motor 1 is reversed, and the rotation direction is changed from the oil passage 41B to the oil passage 42B in FIG.
The flow direction of the hydraulic oil that had been flowing inward is reversed and flows in the direction of arrow C' in the oil passage 42B.

However, in this embodiment, the hydraulic chamber 44B is connected to the valve seat 4.
The valve seat 43 is located closer to the oil pressure source side than 3B.
The hydraulic chamber 44B is disposed substantially in a straight line with the oil passage 42B, and the hydraulic chamber 44B and the oil passage 42B are permanently connected. A communication passage 49B for communication is bored in the poppet valve body 46B in the axial direction. As a result, immediately after the directional control valve 4 is suddenly switched from the right switching position to the left switching position, the poppet valve body 46B is largely separated from the valve seat 43B;
The oil flow in the direction of arrow C' is caused by the poppet valve body 46.
Fluid force F' acts on B in the valve closing direction. Therefore, this fluid force F' together with the biasing force of the spring 48B displaces the poppet valve element 46B in the valve closing direction, allowing it to be quickly seated on the valve seat 43B.

Therefore, in this embodiment, the rotational direction of the hydraulic motor 1 is reversed, and the flow rate of hydraulic oil from the hydraulic motor 1 is changed at a stage before the hydraulic motor 1 is normally rotated in this reversed direction. Before the increase,
The poppet valve body 46B can be seated on the valve seat 43B quickly and with good response, and unlike the prior art, the poppet valve body 46B can be seated in the oil passages 12B and 42B (corresponding to the oil passage 25B used in the prior art) due to a delay in response. It is possible to prevent the generation of surge pressure, and it is possible to reliably prevent a situation where the brake valve, hydraulic motor, etc. are damaged.

Furthermore, even if the directional control valve 4 is switched from the left switching position to the right switching position by jumping over the neutral position, the poppet valve body 46
A can be quickly and responsively seated on the valve seat 43A, and generation of surge pressure can be prevented.

In the above embodiment, when the inertial force of the hydraulic motor 1 and the inertial body 2 is very small, the directional control valve 4 is moved from the right position to the left position or from the left position to the right position, jumping over the neutral position. Although it was mentioned that it can prevent the generation of surge pressure when switching,
This refers to the case where the mass of the inertial body 2 is small or the acceleration is large. Also, inertial body 2
Even if the mass of the inertial body 2 is large, if a speed reducer is interposed between the inertial body 2 and the hydraulic motor 1, the hydraulic motor 1 will momentarily enter a no-load operation state due to the backlash of the gears, and even in this case, the surge pressure will be reduced. can be prevented from occurring.

Further, in the above embodiment, a construction machine is used as an example of an inertial body, and the brake valve is provided in a hydraulic circuit that drives the construction machine to run. However, the present invention is not limited to this, and It can also be applied to brake valves provided in hydraulic circuits other than driving or hydraulic circuits other than construction machinery. Furthermore, in the above embodiment, each communication passage 49A, 49B is connected to each poppet valve body 46A, 46B.
However, instead of this, communication passages 49A and 49B may be provided in the casing 10 so that the oil passages 12A and 12B are permanently communicated with the hydraulic chambers 44A and 44B. good.

[Effect of idea]

As detailed above, according to the present invention, the hydraulic chamber of the check valve is opened to face the valve seat at a position closer to the hydraulic pressure source side than the valve seat, and this hydraulic chamber is permanently connected to the actuator side oil passage. In addition to communicating with
Since the poppet valve body is configured to open due to pressure from the oil pressure source side oil passage acting from the radially outer side of the valve seat, when the rotation direction of the actuator, for example, a hydraulic motor is reversed, the actuator side oil passage The poppet valve element can be quickly seated on the valve seat by utilizing the fluid force exerted by the oil inside the poppet valve element. Therefore, generation of surge pressure can be prevented, and damage to brake valves, hydraulic motors, etc. can be reliably prevented.

[Brief explanation of drawings]

1 and 2 show a brake valve according to an embodiment of the present invention, FIG. 1 is a longitudinal sectional view thereof, and FIG. 2 is a sectional view of a main part showing the operating state of one of the check valves shown in FIG. 1. 3 to 5 relate to the prior art, FIG. 3 is a hydraulic circuit diagram, FIG. 4 is a vertical sectional view of the brake valve shown in FIG. 3, and FIG. 5 is shown in FIG. 4. FIG. 3 is a sectional view of a main part showing the operating state of one check valve. DESCRIPTION OF SYMBOLS 1...Hydraulic motor, 2...Inertia body, 4...Directional switching valve, 5...Hydraulic pump, 6...Tank, 7...
...Counter balance valve, 8A, 8B...Check valve, 10...Casing, 12A, 12B, 14
A, 14B, 41A, 41B, 42A, 42B...
...Oil passage, 15A, 15B, 16A, 16B...Oil chamber, 31A, 31B,...Oil passage, 43A, 43
B...Valve seat, 44A, 44B...Hydraulic chamber, 46
A, 46B...Poppet valve body, 48A, 48B...
...Spring, 49A, 49B...Communication path.

Claims (1)

[Scope of utility model registration request] a casing, a pair of oil passages provided within the casing, each having one end connected to an actuator side and the other end connected to a hydraulic power source side, and a counterbalance valve provided in the middle of each oil passage;
A brake valve comprising a pair of check valves provided in the middle of the oil passage and allowing flow of hydraulic oil from the oil pressure source side toward the actuator side,
Each of the check valves has a valve seat provided in the middle of each of the oil passages, and is provided in the casing so as to be located closer to the oil pressure source side than the valve seat and open opposite the valve seat. a poppet valve body that is slidably inserted into the hydraulic chamber and separates and seats on the valve seat to define each of the oil passages into a hydraulic power source side oil passage and an actuator side oil passage. a spring that biases the poppet valve body toward the valve seat; and a communication passage that permanently communicates the hydraulic chamber with the actuator side oil passage, and the poppet valve body has a hydraulic pressure source side A brake valve characterized in that a pressure receiving surface is formed that causes the poppet valve body to open against the spring when pressure from an oil passage acts from the outside in the radial direction of the valve seat.