JP2538161Y2 - Two-way relief valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention restricts the flow of high-pressure fluid discharged from a fluid motor when the fluid motor performs a pump action, and applies a brake to the fluid motor. The present invention relates to a two-way operation relief valve used for a fluid brake device or the like.

[Conventional technology]

As shown in FIG. 5, first and second main circuits 3, 4 connecting the first and second ports 1a, 1b of the fluid motor 1 and the operation valve 2 have check valves 5 and operation valves from the fluid motor 1. A brake valve 6 for regulating the flow of fluid to the fluid motor 1 is provided. When the fluid motor 1 performs a pumping operation, the flow of the high-pressure fluid discharged from the fluid motor 1 is restricted by the brake valve 6 to apply a brake to the fluid motor 1. Working fluid brake devices are known.

In such a fluid brake device, since the pressure between the fluid motor 1 and the brake valve 6 in the first and second main circuits 3 and 4 becomes high, the first main circuit is provided by providing a pair of relief valves 7 and 7. 3 is relieved to the second main circuit 4, and the high-pressure fluid of the second main circuit 4 is relieved to the first main circuit 3.

Such a fluid brake device is provided with a pair of relief valves, so that the number of parts is large and the cost is high. In addition, since two safety valve mounting holes are formed, the processing becomes troublesome. Since the mounting is performed over the main circuit and the second main circuit, the field area is increased.

Therefore, as shown in Japanese Utility Model Application Laid-Open No.
There has been proposed a fluid brake device provided with a single relief valve that operates in both directions over the second main circuit. This relief valve has a pressure receiving area on the first main circuit side and a pressure receiving area on the second main circuit side. However, since the flow path shape is different, the relief start pressure and the relief pressure are different.

Therefore, the present applicant has previously filed an application for a two-way operation relief valve that can solve the above-mentioned problems.

That is, as shown in FIG. 6, a first port 12 and a second port are connected to a hydraulic device main body 11 such as a motor main body of a fluid motor.
13 and a hole communicating between the first port 12 and the second port 13
A cylindrical body 15 and a sleeve 16 which constitute the two-way operation relief valve 10 are fitted in the holes 14 respectively. The cylindrical body 15 has a large diameter portion as shown in FIG. 17 and small diameter part
18 and a through hole 19, the large diameter portion 17 fits tightly into the hole 14 via the sealing material 20, the through hole 19 opens in the first port 12, and the distal end of the sleeve 16 has a base intermediate diameter hole It has a large-diameter hole 22 and a small-diameter hole 23 at the tip, and a hole 24 is formed in the large-diameter hole 22 at the middle. The free piston 25 is slidably fitted in the base intermediate diameter hole 21 of the sleeve 16.

A piston 27 provided in a spring receiver 26 is slidably fitted into one side blind hole 25a of the free piston 25 to form a pressure receiving chamber 28, and the pressure receiving chamber 28 is formed with a fine hole 29 in an outer blind hole 25b. The open side, the other side blind hole 25b communicates with the through hole 19 of the tubular body 15, and the free piston 25 is pushed by the spring 30 toward the tubular body 15 so that the tapered surface 25c is Small diameter section at 28
The spring chamber 31 is connected to the drain path 32
To communicate with the tank 33.

As shown in FIG. 7, a plurality of pores 29 of the free piston 25 are formed at intervals on a circumference excluding the center of the partition 25d of the free piston 25.

In the case of the aforementioned two-way operation relief valve, the first port 12
And the second port 13 is a front end surface 18 of the small diameter portion 18 of the cylindrical body 15.
a of the free piston 25 and the tapered surface 25c of the free piston 25, and the free piston 25 is moved against the spring 30 by the high-pressure fluid of the first port 12 and the high-pressure fluid of the second port 13 so as to move to the first port 12 And the second port 13
The pressure receiving area S ₁ of the free piston 25 where the high pressure fluid of the first port 12 acts is the diameter d _{1 of the} crimping portion and the diameter of the piston 27.
By the d ₂ are determined by equation (1), the pressure-receiving area S ₂ high pressure fluid in the second port 13 in the free piston 25 Ru action by the diameter d ₃ of diameter d ₁ and the free piston 25 of the crimping portion (2 )
Each diameter d ₁ , d ₂ , By setting d _{3 so} that S ₁ = S ₂ , the free piston 25
Since the pressure receiving areas on which the high pressure fluids of the first and second ports 12 and 13 act are equal, the relief start pressure for relief by the high pressure fluid of the first port 12 and the relief start pressure for relief by the high pressure fluid of the second port 13 Are the same.

Further, since a plurality of pores 29 are formed on the circumference other than the center of the partition 25d of the free piston 25, the first port
The override performance when the high-pressure fluid is relieved from 12 to the second port 13 is improved.

That is, when the high-pressure fluid is relieved from the first port 12 to the second port 13, the pressure distribution A of the partition 25d of the free piston 25 becomes as shown in FIGS. 8 and 9, and as shown in FIG. When is located at the center of the partition 25d of the free piston 25, the high-pressure oil in the high-pressure portion A 'enters the pressure receiving chamber 28 through the pores 29, so that the force in the direction in which the free piston 25 is closed is increased and the override performance is deteriorated. If the small holes 29 are provided on the circumference as shown in FIG. 9, the low-pressure oil in the low-pressure portion A "enters the pressure receiving chamber 28 through the small holes 29, so that the force in the direction in which the free piston 25 is closed becomes small, and the override performance is reduced. Will be better.

Further, the fluid passage is the same whether the relief is performed from the first port 12 to the second port 13 or the relief is performed from the second port 13 to the first port 12. And the crimping portion of the distal end portion 18a of the cylindrical body 15, and the free piston 25 and the spring 30 are common.

Further, since the sleeve 16 can be removed in a state where the two-way operation relief valve 10 is assembled by extracting the sleeve 16 from the valve main body 11, the removal and mounting work becomes easy.

Also, loosen the lock nut 34 and tighten the spring receiver 26,
By loosening, the mounting load of the spring 30 can be changed to adjust the relief start pressure.

[Problems to be solved by the invention]

As described above, the two-way relief valve previously filed by the present applicant can solve the problems of the conventional relief valve, but the force acting on the free piston 25 is not balanced. Becomes Here, P _A is the pressure at the first port 12, P _B is the pressure at the second port 13, and F _S is the spring force of the spring 30.

Since this be the case, the free piston in a condition where the sum of the pressure P _B of the pressure P _A and the second port 13 of the first port 12 becomes constant
25 begins lileg operation. (It operates on the broken line in FIG. 10).

For this reason, the high-pressure side pressure at the start of the relief operation is affected by the low-pressure side force. Therefore, the high-pressure side pressure at the start of the relief operation decreases by the rise of the low-pressure side pressure due to the circuit back pressure or the like.

Therefore, an object of the present invention is to provide a two-way operation relief valve capable of solving the above-mentioned problem.

[Means and actions for solving the problem]

A cylindrical body 15 having a through hole 19 communicating the first port 12 and the second port 13, one of which is at a high pressure while the other is at a low pressure, a blind hole 25 a on one side and a blind hole 25 b on the other side with a partition 25 d as a boundary. One side blind hole 2 on the circumference other than the center of the partition 25d.
A free piston 25 having a plurality of small holes 29 communicating the 5a and the other blind hole 25b, a tapered surface 25c on the other blind hole 25b side of the free piston 25;
Is pressed against one end surface of the cylindrical body 15 to make the first port 12 and the second port
A spring 30 that shuts off the port 13; a piston 27 that is inserted into one blind hole 25a of the free piston 25 to form a chamber between the partition wall 25d; A shuttle piston 43 forming a pressure receiving chamber 28 communicating with the hole 19 and a pressing chamber 44 communicating with the second port 13 side; and a back pressure chamber 42 for pushing the free piston 25 in a blocking direction by inflow pressure oil. When the pressure on the first port 12 side is higher than the pressure on the second port 13 side, the piston 43 moves to the first position by the pressure on the first port 12 side flowing into the pressure receiving chamber 28, and the second port 13 side When the pressure is higher than the pressure on the first port 12 side, it moves to the second position by the pressure on the second port 13 side flowing into the pressing chamber 44, and when the shuttle piston 43 is in the first position, the second position is reached.
The port 13 side communicates with the back pressure chamber 42, and when the shuttle piston 43 is in the second position, the first port 12 side communicates with the back pressure chamber 42. The cylindrical body 1 on the tapered surface 25c of the free piston 25
The second port 1 is located on the outer peripheral portion from the pressure contact portion with one end surface of
The pressure on the first port 12 acts on the inner peripheral portion of the pressure-applied portion, and the pressure on the first port 12 acts on the inner peripheral part of the free piston 25.
Is pressed in the direction of communication between the first port 12 and the second port 13 and the free piston is acted upon by the pressure on the second port 13 side.
A two-way operation relief valve characterized in that a pressure receiving area for pressing 25 in a direction connecting the first port 12 and the second port 13 and a pressure receiving area of the back pressure chamber 42 are the same.

As a result, the pressure at which relief is started with the high-pressure fluid on the first port 12 side and the pressure at which relief is started with the high-pressure fluid on the second port 13 side can be made equal, and the force for pushing the free piston 25 in the communicating direction with the low-pressure side pressure. Offset by the low-pressure side pressure introduced into the back-pressure chamber 42 to prevent the high-pressure side pressure at the start of relief from being affected by the low-pressure side pressure, simplifying installation space, machining, and oil passages. it can.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. 1 and FIG. The same members as those in the related art are denoted by the same reference numerals, and description thereof is omitted.

The outer peripheral surface of the free piston 25 is stepped so that the outer peripheral surface 40 on one side thereof has a small diameter, and an annular projection 41 is formed in the base intermediate diameter hole 21 of the sleeve 16 to form an outer peripheral surface 40 on one side of the free piston 25. An annular back pressure chamber 42 is formed between the back pressure chamber 21 and the base intermediate diameter hole 21, and the shuttle piston 43 introduces the pressure of the low pressure side port into the back pressure chamber 42 to apply a force in the closing direction to the free piston 25. It is like that.

The shuttle piston 43 is inserted into one side blind hole 25a of the free piston 25 to form a pressure receiving chamber 28 and a pressing chamber 44, and the pressing chamber 44 is formed on the first port 45 and the outer peripheral surface of the free piston 25. The first slit 46 opens to the second port 13 side, and the back pressure chamber 42 opens to the one side blind hole 25a at the second slit 47 and the second port 48 formed on the outer peripheral surface of the free piston 25. 43 on the outer peripheral surface of the 43
A slit 49 is formed so that the shuttle piston 43 communicates the second port 48 with one of the pressure receiving chamber 28 and the pressing chamber 44.

Thus, when the pressure P _A in the first port 12 of the high pressure first
As shown in the figure, the shuttle piston 43 is pushed to the right by the high-pressure oil flowing into the pressure receiving chamber 28 to communicate the second port 48 with the pressing chamber 44 through the third slit 49, and to connect the second port 48 and the pressure receiving chamber 28. The pressure P _B of the second port 13 is shut off, and the pressure P _B of the second port 13 is reduced to the first slit 46, the first port 45, the pressing chamber 44, the third slit 49, the second port 48,
Free piston 25 introduced into back pressure chamber 42 through slit 47
Press in the blocking direction.

Further, the second port 48 is pushed to the left so that the pressure P _B is the shuttle piston 43 is a second diagram with high pressure oil flows into the pressing chamber 44 when a high pressure second port 13 third slit 49
To the pressure receiving chamber 28, and the pressure of the first port 12 on the low pressure side.
P _A is the pressure receiving chamber 28, the third slit 49, second port 48, it is introduced into the back pressure chamber 42 from the second slit 47 pressing the free piston 25 in the blocking direction.

That is, the shuttle piston 43 applies the pressure of the first port 12
When P _A is high, it is in the first position and the pressure P _{B in} the second port 13
It was supplied to the back pressure chamber 42, when the high pressure P _B of the second port 13 for supplying the pressure P _A in the first port 12 is the second position to the back pressure chamber 42.

Because of this, when P _A > P _B (the state of FIG. 1), the balance of the force acting on the free piston 25 is determined by the pressure P of the second port 13 acting on the back pressure chamber 42 by the free piston 25. _Since it is pushed to the left in Fig. 1 at _B , Becomes

In addition, the free piston when P _A <P _B (the state in FIG. 2)
The force balance acting on the 25 is such that the free piston 25 is
It is pushed to the left in FIG. 2 by the pressure P _A of the first port 12 acting on 42. Second port free piston 25 from the shuttle piston 43 in the pressure P _B in the second port 13 acting on the pressing chamber 44 is brought into contact with the partition wall 25d of the free piston 25 acting on the pressing chamber 44
13 pressure P _B in the pushed in Figure 2 left. Free piston Moreover at a pressure P _A in the first port 12 acting on the pressure P _A is the area of without [pi / 4d ₁ ² operation of the first port 12 to the shuttle piston 43
25 is pushed to the right in Figure 2, so Becomes However, d ₄ is the diameter of the outer peripheral surface 40 on one side of the free piston 25, Is the pressure receiving area that pushes the free piston 25 to the closing side.

Moreover the pressure-receiving area of pushing the free piston 25 the pressure P _A acts first port 12 rightward in FIG. 1 when P _A> P _B When P _A <P _B , the pressure P _B of the second port 13 acts to push the free piston 25 rightward in FIG. Pressure receiving area where the pressure on the low pressure side is introduced Are equal.

That the condition of the diameter _{d 1, d 2, d 3} , d 4 is d ₃ ² -d ₁ ² =
than ^{_{d 3 2 -d 4 2, d}} 1 2 = d 3 2 -d 4 2, d 1 2 -d 2 2 = d 3 2 -d 1 2 -d 2 2, And d ₁ = d ₄ .

Therefore, since the free piston 25 is pushed in the closing direction by the low pressure side pressure introduced into the back pressure chamber 42, the force of pushing the free piston 25 in the opening direction is canceled by the low pressure side pressure, and the relief operation of the free piston 25 is performed. The pressure is as shown by the solid line in FIG. 10, and the high pressure on the high pressure side at the start of the relief operation can be increased without being affected by the pressure on the low pressure side.

FIGS. 3 and 4 show a second embodiment, in which a shuttle piston 43 is inserted into a blind hole 27a of a piston 27 to form a pressing chamber 44 facing the pressure receiving chamber 28. The pressing chamber 44 is firstly formed by the fourth slit 50 and the third port 51 formed.
A second port 48 of the free piston 45 is opened in a blind hole 27a by a fifth slit 52 and a fourth port 53 formed on the outer peripheral surface of the piston 27, and a shuttle chamber 43 A first oil passage 54 opened on the outer peripheral surface, a pressure receiving chamber 28, and a second oil passage 55 opened on the outer peripheral surface are formed, and when the shuttle piston 43 slides rightward, the pressing chamber 44 becomes the first oil passage.
When the shuttle piston 43 slides leftward, the pressure receiving chamber 28 communicates with the fourth port 53 through the second oil passage 55 when the shuttle piston 43 slides leftward.

Thus, the shuttle piston 43 when the pressure P _A is the pressure of the first port 12 is slid to the right as shown in FIG. 3,
The pressure P _B of the second port 13 on the low pressure side is
Port 45, first oil passage 54, fourth port 53, fifth slit 5
2, second port 48, is introduced to the back pressure chamber 42 from the second slit 47, the force pushing the free piston 25 in the extending direction by the pressure P _B in the second port 13 of the low pressure side by pressing the free piston 25 in the blocking direction cancel.

In other words, the balance of forces acting on the case free piston 25, since the free piston 25 by the pressure P _B in the second port 13 acting on the back pressure chamber 42 is pressed in FIG. 3 the left, Becomes

Further, the free piston 25 by the pressure of the high pressure supplied to the pressing chamber 44 when the pressure P _B in the second port 13 is a high pressure slides to the left as shown in Figure 4, the pressure-receiving chamber 28 pressure P _a second oil passage 55 of the first port 12 is low-pressure side, the fourth port 5
3, fourth slit 52, second port 48, is introduced to the back pressure chamber 42 through the second slit 47, the free piston 25 by the pressure P _A in the first port 12 of the low pressure side by pressing the free piston 25 in the blocking direction Cancels the pushing force in the communication direction.

In other words, the balance of forces acting on the case free piston 25, the free piston 25 by the pressure P _A in the first port 12 acting on the back pressure chamber 42 is pressed in FIG. 4 the left, acting on the pressing chamber 44 Shuttle piston 43 by the pressure P _B in the second port 13 is in contact with free piston 25 in the partition wall 25d of the free piston 25 is pushed in Fig. 4 left at a pressure P ₃ of the second port 13 acting on the pressing chamber 44, Moreover the pressure P _a in the first port 12 flows into the pressure chamber 28 does not act on the shuttle piston 43 The free piston 25 is pushed rightward in FIG. 4 by the pressure P _A of the first port 12 acting on the area of Since the, the _{d 1 = d 4, 2d 1} 2 = d 2 2 + d 3 2 -d 5 2.

[Effect of the invention]

The pressure at which relief is started with the high-pressure fluid on the first port 12 side and the pressure at which relief is started with the high-pressure fluid on the second port 13 side can be made the same.

The force of the low-pressure side acting on the free piston 25 that is pushed in the communication direction can be offset by the low-pressure side pressure introduced into the back pressure chamber 42, so that the high-pressure side pressure at the start of the relief is affected by the low-pressure side pressure. The high-pressure side pressure at the time of starting relief without receiving can be kept constant. Moreover, since the shuttle piston 43 for introducing the pressure on the low pressure side into the back pressure chamber 42 is provided in the free piston 25, the mounting area, processing, and oil passage of the relief valve can be simplified.

[Brief description of the drawings]

1 and 2 are sectional views showing a first embodiment of the present invention, FIGS. 3 and 4 are sectional views of a second embodiment, FIG. 5 is a sectional view showing an example of a fluid brake device, FIG. 6 is a cross-sectional view of the two-way operation relief valve previously filed, FIG. 7 is a side view of the free piston, FIGS. 8 and 9 are explanatory views of pressure oil flowing into the pressure receiving chamber from the small holes, and FIG. FIG. 10 is a chart showing the relief start pressure. 12 is the first port, 13 is the second port, 25 is the free piston, 28 is the pressure receiving chamber, 29 is the pore, 30 is the spring, 42 is the back pressure chamber, 43
Is a shuttle piston.

Claims (1)

(57) [Scope of request for utility model registration] 1. A tubular body 15 having a through-hole 19 communicating one port 12 and second port 13 which is connected to a first port 12 and a second port 13 when one is at a high pressure and the other is at a low pressure. It has a side blind hole 25b,
A free piston 25 having a plurality of pores 29 communicating the one side blind hole 25a and the other side blind hole 25b on a circumference other than the center of the partition wall 25d; and a taper on the other side blind hole 25b side of the free piston 25. A spring 30 that presses the surface 25c against one end surface of the cylindrical body 15 to shut off the first port 12 and the second port 13;
5d, a piston 27 that forms a chamber, a shuttle piston that is inserted into the chamber, and that forms a pressure receiving chamber 28 that communicates with the through hole 19 through the fine hole 29 and a pressing chamber 44 that communicates with the second port 13 side. 43, and a back pressure chamber 42 for pushing the free piston 25 in the shut-off direction by the inflow pressure oil. The shuttle piston 43 is a pressure receiving chamber when the pressure on the first port 12 side is higher than the pressure on the second port 13 side. When the pressure on the second port 13 side is higher than the pressure on the first port 12 side, it moves to the first position due to the pressure on the first port 12 side flowing into the second port 13 flowing into the pressing chamber 44. When the shuttle piston 43 is in the first position, the second port 13 communicates with the back pressure chamber 42 when the shuttle piston 43 is in the first position, and when the shuttle piston 43 is in the second position, the first port 12 side communicates with the back pressure chamber. The cylindrical body 15 on the tapered surface 25c of the free piston 25
The second port 13 is provided on the outer peripheral portion of the outer peripheral portion of the pressure contact portion with one end surface of the
Pressure acts on the first port 12 side on the inner peripheral portion of the pressure contact portion. The pressure on the first port 12 acts to move the free piston 25 to the first port 12. The pressure receiving area that pushes the second port 13 in the communicating direction and the pressure on the second port 13 side act to operate the free piston 25.
A pressure receiving area for pushing the pressure in the direction in which the first port 12 and the second port 13 communicate with each other, and a pressure receiving area of the back pressure chamber 42 are the same.