JP2002195207A - Booster cylinder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase working property by suppressing the generation of pressure loss in a booster cylinder device. SOLUTION: This cylinder device installs a hysteresis valve 40, controlling a booster cylinder 8, between a communicating passage 15 communicating the inlet port P1 of a booster cylinder 8 to the discharge port of a hydraulic pump 2. The booster cylinder 8 supplies a boosted pressure into the bottom chamber 3 of a hydraulic cylinder 1. The booster cylinder 8 begins to work immediately after the hysterisis valve 40 opens. Furthermore, the hysterisis valve keeps the open condition if pressure loss generates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-intensifying cylinder device used in a crusher for crushing an object to be crushed such as concrete.

[0002]

2. Description of the Related Art A pressure-intensifying cylinder device is designed such that when the pressure oil sent to a working hydraulic cylinder reaches a certain pressure,
The booster cylinder is operated, and the booster oil formed by the booster cylinder is supplied to the hydraulic cylinder. Such an intensifying cylinder device is widely used for driving a crusher for crushing a concrete lump or the like.

[0003] As a pressure-increasing cylinder device as described above,
The present applicant has already proposed what is described in Japanese Patent Publication No. 7-6524.

As shown in FIG. 4, this pressure-intensifying cylinder device includes a working hydraulic cylinder 1, a hydraulic pump 2 for supplying hydraulic oil to the hydraulic cylinder 1, and a hydraulic pump 2.
Pressure oil discharged from the bottom chamber 3 of the hydraulic cylinder 1
An operation valve 7 for selectively switching and supplying a first passage 4 communicating with the first passage 4 and a second passage 6 communicating with the rod chamber 5, and a booster cylinder 8 for supplying booster oil to the bottom chamber 3 of the hydraulic cylinder 1. Have.

[0005] A pilot check valve 9 is incorporated in the first passage 4, and the pilot check valve 9 prevents the pressure oil in the bottom chamber 3 of the hydraulic cylinder 1 from flowing back to the hydraulic pump 2 side.

The booster cylinder 8 includes a cylinder body 10
And a pressure increasing piston 11 incorporated therein.
The piston 11 is provided with a large diameter portion 11a and small diameter portions 11b on both sides thereof. On the other hand, a large-diameter chamber 12 that guides the large-diameter portion 11a slidably in the cylinder body 10,
First pressure-increasing chamber 13 that guides small-diameter portion 11b slidably.
a and a second pressure-intensifying chamber 13b are formed.
Reference numerals a and 13b communicate with the bottom chamber 3 of the hydraulic cylinder 1 via a passage.

An import P ₁ , a pilot port P ₂ and a tank port P ₃ are formed in the cylinder body 10 at intervals in the direction of movement of the piston 11, and the import P ₁ is connected to the first through a communication passage 15. The passage 4 communicates with the inlet side of the pilot check valve 9 and the pilot port P
₂ communicates with the pilot chamber 21 of the switching valve 20 via the passage 16. Also, the tank port P ₃ is communicated with the tank T via the passage 17.

The piston 11 in the booster cylinder 8
While the small diameter portion 11b of the circumferential groove of the switching換通path 18 is provided, this switching換通path 18 when the piston 11 moves to the vicinity limit position of the forward stroke, communicating the import P ₁ and the pilot port P ₂ With piston 1
When 1 moves to near the limit position of the return stroke,
So that the communicating pilot port P ₂ and the tank port P _3.

The switching valve 20 has a P port P ₁₁ and a T port P ₁₂
And A and B ports P ₁₃ and P _{14. The} P port P ₁₁ communicates with the discharge port of the hydraulic pump 2 through a passage 22, and a sequence valve 23 is incorporated in the passage 22.

On the other hand, T port P ₁₂ is communicated with the tank T via the passage 24, the check valve 25 is incorporated in the passage 24. Further, the A port P ₁₃ communicates with the first pressurizing chamber 12 a partitioned by the large diameter portion 11 a of the large diameter chamber 12 in the booster cylinder 8 via the passage 26, and the B port P ₁₄ communicates with the first pressure chamber 12 via the passage 27. 2 communicates with the pressure chamber 12b.

Reference numeral 31 denotes a relief valve for holding the pressure of the pressure oil at the time of extension of the hydraulic cylinder 1 at a set value.
Denotes a relief valve for holding the pressure of the pressure oil at the time of contraction of the hydraulic cylinder 1 at a set value.

In the pressure-intensifying cylinder device having the above structure, when the operating valve 7 is switched to the position a, the pressure oil discharged from the hydraulic pump 2 is supplied from the first passage 4 to the bottom chamber 3 of the hydraulic cylinder 1. The piston A and the piston rod B move forward by the supply of the pressure oil.

At this time, the oil in the rod chamber 5 of the hydraulic cylinder 1 is returned from the second passage 6 to the tank T.

The load on the piston rod B increases,
If the load exceeds the set pressure of the sequence valve 23 to open the sequence valve 23, the pressure oil from the hydraulic pump 2 flows from the passage 22 to the P port P ₁₁ of the switching valve 20. At this time, the P port P ₁₁ is in communication with the A port P _13, the pressure oil flows from the A port P ₁₃ to the first pressure chamber 12a of the booster cylinder 8, the piston 1 of the booster cylinder 8
1 moves to the right side of FIG.

By the movement of the piston 11, pressure oil having a pressure higher than the pressure oil of the hydraulic pump 2 is formed in the second pressure increasing chamber 13b, and the pressure increasing oil is supplied to the bottom chamber 3 of the hydraulic cylinder 1.

[0016] When the piston 11 is moved to the vicinity limit position of the forward stroke, communicates via an import P ₁ and the pilot port P ₂ is switching換通passage 18 of the booster cylinder 8, the pilot chamber 21 of the switching valve 20 by the communication
The supplied pressurized oil, the spool 28 of the switching valve 20 is against the elasticity of the spring 29 moves to the left in FIG. 4, communicates with the P port P ₁₁ and the B port P _14.

[0017] by the switching of the switching valve 20, the pressure oil from the hydraulic pump 2 flows from the P port P ₁₁ to the B port P _14, the second pressure chamber from the passage 27 of the booster cylinder 8 1
2b, the piston 11 of the booster cylinder 8 moves (returns) to the left side in FIG.

Due to the backward movement of the piston 11, pressure oil having a pressure higher than the pressure oil of the hydraulic pump 2 is formed in the first pressure boosting chamber 13a, and the pressure boosting oil is supplied to the bottom chamber 3 of the hydraulic cylinder 1.
Supplied to

When the piston 11 of the booster cylinder 8 moves to near the limit position of the return stroke, the pilot port P ₂ of the booster cylinder 8 communicates with the tank port P _3, and the oil in the pilot chamber 21 of the switching valve 20 passes through the passage 1.
6, switching換通path 18 and flows into the passage 17 is returned to the tank T, P port P ₁₁ the spool 28 of the switching valve 20 is moved to the right by the elastic force of the spring 29 and the A port P ₁₃
Communicate. The pressure oil is supplied to the first pressurizing chamber 12a of the booster cylinder 8 by the communication, so that the pressure-increasing piston 11 moves forward.

As described above, in the pressure-intensifying cylinder device, pressure-increasing oil is formed both in the forward movement and the backward movement of the piston 11 of the booster cylinder 8, and the pressure-increasing oil is formed in the bottom chamber 3 of the hydraulic cylinder 1. , The hydraulic cylinder 1 can be operated very efficiently.

Further, by operating the booster cylinder 8, the pressure can be raised to a pressure obtained by multiplying the area ratio m (> 1) between the large diameter portion 11a and the small diameter portion 11b of the piston 11 by the set pressure of the relief valve 31. The hydraulic cylinder 1 can be driven at a high pressure.

[0022]

In the pressure-intensifying cylinder device shown in FIG. 4, when the sequence valve 23 is opened by hydraulic oil discharged from the hydraulic pump 2,
As shown in FIG. 5, the pressure P downstream of the sequence valve 23
Although o increases, the pressure at the initial stage of opening is lower than the set pressure of the sequence valve 23, and is 1 / m of the set pressure of the sequence valve 23.
Down to Thereafter, the pressure rises with the rise of the cylinder load, and finally reaches the set pressure (Psequence) of the sequence valve 23, and thereafter the fully open state is maintained. That is, when the load pressure of the hydraulic cylinder 1 is Psequence
When operating in the range of nce to (Psequence × m), a pressure loss occurs in a region indicated by oblique lines in FIG.

Also, the set pressure of the sequence valve 23 must be at most 1 / m or less of the maximum drive pressure of the hydraulic cylinder 1, in other words, the set pressure of the relief valve 31 or less. Although it is desired to increase the pressure, the higher the pressure, the greater the pressure loss, so it is necessary to keep the set pressure low. As a result, unnecessary pressure increase operation occurs even in a pressure region where pressure increase is not necessary. There is an inconvenience.

Since the sequence valve 23 needs to pass the entire amount of pressure oil discharged from the hydraulic pump 2,
It is necessary to use the sequence valve 23 having a large capacity, which is not only disadvantageous in terms of cost but also requires a large space for mounting.

It is a technical object of the present invention to suppress the occurrence of pressure loss and improve the operating efficiency of a hydraulic cylinder in the pressure-intensifying cylinder device as described above.

[0026]

According to the present invention, a hydraulic cylinder for working, a hydraulic pump for supplying hydraulic oil to the hydraulic cylinder, and a bottom chamber of the hydraulic cylinder are provided. An operation valve for selectively supplying pressurized oil discharged from the hydraulic pump to the rod chamber, and a pressurizing piston is reciprocated by the pressurized oil from the hydraulic pump to form pressurized oil, and the pressurized oil is hydraulically A booster cylinder that supplies a booster cylinder to a bottom chamber of the cylinder, and a switching valve that switches and supplies pressure oil discharged from the hydraulic pump to a chamber for moving a piston of the booster cylinder forward and a chamber for returning the piston. The cylinder body of the booster cylinder, an import communicating with a discharge port of a hydraulic pump, a pilot port communicating with a pilot chamber of a switching valve, and a tank communicating with a tank. A switching valve that connects the import and the pilot port to the booster piston near the limit of the forward stroke of the piston and the import and the tank port near the limit of the return stroke of the piston. In a pressure-intensifying cylinder device provided with a switching passage for operation, a hysteresis valve is provided in a communication passage that communicates the import of the booster cylinder with a discharge port of a hydraulic pump, and the hysteresis valve is set in advance with a discharge pressure of the hydraulic pump. When the pressure exceeds the set pressure, the port is opened, and the opening causes communication between the import and the discharge port of the hydraulic pump.After the communication, a pressure drop in the communication passage from the discharge port of the hydraulic pump to the import of the hysteresis valve may occur. It was configured to maintain the open state.

As described above, by providing the hysteresis valve in the communication passage connecting the import of the booster cylinder and the discharge port of the hydraulic pump, only the pilot flow required for switching the switching valve can be controlled. Immediately after opening, even if the pressure in the communication path decreases, the completely open state is maintained, so until the pressure in the communication path rises to the set pressure of the hysteresis valve, the above small flow rate can be said. However, generation of pressure loss can be suppressed. After the hysteresis valve is opened, the pressure is increased. However, the pressure oil supplied from the hydraulic pump to the booster cylinder is directly led to the piston of the booster cylinder, so there is no loss as before, and the operating efficiency of the hydraulic cylinder is improved. Can be achieved.

Here, even if a pressure drop occurs on the import side of the hysteresis valve immediately after the opening of the hysteresis valve, as a means for maintaining the hysteresis valve in an open state, a method of establishing a relationship of Po ≦ Pu / m is established. Can be adopted.

Here, Po is the set pressure of the hysteresis valve, Pu is the reset set pressure of the hysteresis valve, and m is the area ratio between the large diameter portion and the small diameter portion of the booster piston in the booster cylinder.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The same components as those of the above-described pressure-intensifying cylinder device of FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 1, the hysteresis valve 40 is incorporated in the communication passage 15 that communicates the import P ₁ of the discharge port and the booster cylinder 8 of the hydraulic pump 2. As shown in FIG. 2 (I), a hysteresis valve 40 is provided inside a housing 41 with a spool insertion hole 42 formed of a stepped hole.
And an import 43 communicating with the small-diameter hole 42a of the spool insertion hole 42, and a large-diameter hole 4 of the spool insertion hole 42.
An out port 44 communicating with 2b is formed, and a spool 45 is slidably incorporated in the spool insertion hole 42.

The spool 45 has a small-diameter portion 45a slidably supported by the small-diameter hole 42a, and a large-diameter portion 45b slidable in the large-diameter hole 42b is provided at the rear end of the small-diameter portion 45a. I have.

The spool 45 is pressed toward the small-diameter hole 42a by a spring 46 incorporated in the large-diameter hole 42b, thereby blocking the communication between the import 43 and the out port 44.

The small diameter portion 45a of the spool 45 has an annular groove 47, an inner peripheral surface of the annular groove 47 and the small diameter portion 45a.
And a small-diameter hole 48 which is opened at the tip end surface. The annular groove 47 is provided in the closed position where the spool 45 blocks communication between the import 43 and the out port 44.
3, and has an axial width that allows the import 43 and the out port 44 to communicate when the spool 45 is retracted.

The set pressure Pu of the hysteresis valve 40 having the above configuration is set to a value slightly lower than the set pressure of the relief valve 31 shown in FIG. When the hysteresis valve 40 is opened by the discharge pressure from the hydraulic pump 2,
Immediately after the opening, the pressure of the import 43 becomes 1 of the pressure immediately before.
/ M.

Here, m indicates the area ratio between the side surface of the large diameter portion 11a of the piston 11 of the booster cylinder 8 and the end surface of the small diameter portion 11b.

The hysteresis valve 40 maintains the open state even if the pressure is reduced immediately after the opening, so that the return pressure Po, the return set pressure Pu by the spring 46, and the large-diameter portion 11a of the piston 11 in the booster cylinder 8. Between Po and the area ratio m of the small diameter portion 11b, Po
The relationship of ≤Pu / m is established.

The pressure-intensifying cylinder device shown in the embodiment has the above-described structure. When the operation valve 7 shown in FIG. 1 is switched to the position a, the pressure oil discharged from the hydraulic pump 2 The piston rod B is supplied to the bottom chamber 3 of the cylinder 1 and moves forward.

At this time, the switching valve 20 is in a state where the P port P ₁₁ and the A port P ₁₃ are in communication with each other, and the pressure oil flowing from the hydraulic pump 2 to the passage 22 flows from the P port P ₁₁ of the switching valve 20 to the A port. It flows to P _13, and flows into the first pressure chamber 12a of the booster cylinder 8. The pressure oil flowing into the first pressurizing chamber 12a causes the piston 11 to move rightward in FIG. 1 (forward movement) and stop, and the movement of the piston 11 causes the import P ₁ and the pilot port P ₂ to switch to the switching passage 18. To communicate through.

The excess oil that has flowed into the first pressurizing chamber 12 a flows into a passage 50 formed in the piston 11, passes through a check valve 51 provided in the passage 50, and enters the first passage 4. Inflow.

When the piston 11 of the booster cylinder 8 moves forward (moves rightward in the figure), the oil in the second pressurizing chamber 12b
7 flows into the switching valve 20 and the passage 24 and returns to the tank T.

A load is applied to the piston rod B of the hydraulic cylinder 1, and the load is applied to the set pressure P of the hysteresis valve 40.
u, the spool 45 of the hysteresis valve 40
Slides rightward from the state shown in FIG. 2 (I), and the hysteresis valve 40 is brought into an open state in which the import 43 and the out port 44 communicate with each other as shown in FIG. 2 (II).

When the hysteresis valve 40 is opened, the pressure oil discharged from the hydraulic pump 2 flows into the communication passage 15 and the pressure increasing operation starts. At this time, the hydraulic pump 2
The pressure in the portion from the discharge port to the import 43 of the hysteresis valve 40 decreases, but the hysteresis valve 40 is
≦ Pu / m is set so as to satisfy,
The hysteresis valve 40 is kept open. Further, since the switching passage 18 formed in the piston 11 of the booster cylinder 8 is in a state of communicating the import P ₁ and the pilot port P ₂ , the pressure oil supplied to the communication passage 15 flows from the import P ₁ to the pilot port P 2. ₂ and flows into the pilot chamber 21 of the switching valve 20.
The switching valve 20 is switched to the state where the P port P ₁₁ and the B port P ₁₄ communicates (refer to FIG. 3).

Therefore, the pressure oil sent from the hydraulic pump 2 to the passage 22 flows from the P port P ₁₁ of the switching valve 20 to the B port P _14, and flows into the second pressurizing chamber 1 of the booster cylinder 8.
2b, and the piston 1
1 moves (returns) to the left in FIG.
The oil inside is increased. The pressurized oil is supplied from the first passage 4 to the bottom chamber 3 of the hydraulic cylinder 1.

At this time, the pressure in the first passage 4 increases. However, since the pilot check valve 9 is provided in the first passage 4, backflow to the hydraulic pump 2 is prevented.

[0047] When the piston 11 of the booster cylinder 8 is moved to the vicinity limit position of the backward stroke, communicates through the pilot port P ₂ and the tank port P ₃ switching換通path 18, switching valve 20 is incorporated therein The state is switched to the state shown in FIG. 1 in which the P port P ₁₁ and the A port P ₁₃ communicate with each other by the action of the spring 29, and the pressure oil discharged from the hydraulic pump 2 is supplied to the first pressure chamber 12 of the booster cylinder 8.
a.

For this reason, the piston 11 moves forward from the state shown in FIG. 1 to pressurize the oil in the second pressure-intensifying chamber 13b, and the pressure-increasing oil formed by the pressurization causes the pressure in the bottom chamber 3 of the hydraulic cylinder 1 to be increased. Flows into.

Thereafter, the above-described operation is repeatedly performed, the pressing force for pressing the piston rod B of the hydraulic cylinder 1 gradually increases, and the area ratio m (>) of the large diameter portion 11a and the small diameter portion 11b of the piston 11 of the booster cylinder 8 is increased. The pressure can be raised to a pressure obtained by multiplying 1) by the set pressure of the relief valve 32.

As described above, the booster cylinder 8 increases the pressure in both the forward movement and the backward movement of the piston 11 and supplies the increased pressure oil to the bottom chamber 3 of the hydraulic cylinder 1 to operate the hydraulic cylinder 1 efficiently. Can be.

Further, even if the pressure drops immediately after the hysteresis valve 40 is opened, the open state is maintained as long as the pressure does not drop below the return pressure Po, so that no pressure loss occurs. Immediately after the hysteresis valve 40 is opened, the booster cylinder 8 can be operated immediately, and the working efficiency can be improved.

Further, at the time of increasing the pressure, the hydraulic oil from the hydraulic pump 2 is sent to the booster cylinder 8 through the switching valve 20 and does not need to flow through the hysteresis valve 40. Since it is possible to use a small and inexpensive device with a small mounting space and the set pressure of the hysteresis valve 40 can be set to a value slightly lower than the set pressure of the relief valve 31, it is necessary to increase the pressure. It is possible to prevent the booster cylinder 8 from unnecessarily increasing the pressure in a pressure region where there is no pressure.

As shown in FIG. 1, by providing a passage 60 communicating with the passage 24 on the outport 44 side of the hysteresis valve 40 and providing a throttle 61 in the passage 60, the influence of the back pressure on the set pressure is reduced. can do.

[0054]

As described above, according to the present invention, the hysteresis valve which maintains the open state even if the pressure drops immediately after the opening is provided in the communication path which connects the discharge port of the hydraulic pump and the import of the booster cylinder. Incorporating a hydraulic cylinder prevents the occurrence of pressure loss when the booster cylinder and the switching valve are operated using the sequence valve, and operates the booster cylinder immediately after the hysteresis valve is opened. Work efficiency can be improved.

Further, since the hysteresis valve does not repeat the opening / closing operation as in the sequence valve while maintaining the open state immediately after the opening, stable control can be obtained.
It rarely breaks down.

Further, in the case of the hysteresis valve, since the amount of oil flowing in the valve is small, the size can be reduced as compared with the sequence valve, and it is not necessary to secure a large space for mounting.

[Brief description of the drawings]

FIG. 1 is a pressure oil circuit diagram of a pressure-intensifying cylinder device according to the present invention.

FIG. 2 (I) is a cross-sectional view of the hysteresis valve, and (II) is a cross-sectional view showing an open state of the hysteresis valve.

FIG. 3 is a pressure oil circuit diagram showing a pressure-intensifying cylinder device.

FIG. 4 is a hydraulic circuit diagram showing a conventional pressure-intensifying cylinder device.

5 is a graph showing a relationship between a cylinder load and a pressure of the sequence valve shown in FIG.

[Explanation of symbols]

1 the hydraulic cylinder and second hydraulic pump 3 bottom chamber 5 rod chamber 7 operating valve 8 booster cylinder 10 cylinder body P ₁ import P ₂ pilot port P ₃ tank port 11 piston 12a first pressure chamber 12b second pressure chamber 15 communicating path 18 Switching passage 20 Switching valve 40 Hysteresis valve

Claims (2)

[Claims] A hydraulic cylinder for working, a hydraulic pump for supplying hydraulic oil to the hydraulic cylinder, and an operation for selectively supplying hydraulic oil discharged from the hydraulic pump to a bottom chamber and a rod chamber of the hydraulic cylinder. A valve, a booster cylinder that reciprocates a pressure-intensifying piston with pressure oil from the hydraulic pump to form pressure-intensifying oil, and supplies the pressure-intensifying oil to a bottom chamber of the hydraulic cylinder; and a valve that is discharged from the hydraulic pump. A switching valve for supplying pressurized oil by switching between a chamber for moving the piston of the booster cylinder forward and a chamber for returning the hydraulic oil, wherein the cylinder body of the booster cylinder is connected to a discharge port of a hydraulic pump. And a pilot port communicating with the pilot chamber of the switching valve, and a tank port communicating with the tank. A pressure-increasing cylinder device provided with a switching passage for switching valve operation for communicating between the import and the pilot port near the limit position of the suction port and communicating between the pilot port and the tank port near the limit position of the return stroke. A hysteresis valve is provided in a communication path that communicates the import of the cylinder and the discharge port of the hydraulic pump, and the hysteresis valve is opened when the discharge pressure of the hydraulic pump exceeds a preset set pressure. A pressure-increasing cylinder device, wherein the discharge port of the hydraulic pump is communicated, and after the communication, an open state is maintained even if a pressure drop occurs in a communication path from the discharge port of the hydraulic pump to the import of the hysteresis valve. . 2. The pressure setting of the hysteresis valve is Pu,
The relationship of Po ≦ Pu / m is established when the return set pressure is Po and the area ratio between the large diameter portion and the small diameter portion of the booster piston is m (> 1). Booster type cylinder device.