JP3874608B2 - Booster cylinder device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure-increasing cylinder device used in a crusher for crushing a material to be crushed such as concrete.
[0002]
[Prior art]
The pressure-increasing cylinder device operates the booster cylinder when the pressure oil sent to the working hydraulic cylinder reaches a certain pressure, and supplies the pressure-increasing oil formed by the booster cylinder to the hydraulic cylinder. . Such a pressure-increasing cylinder device is widely used for driving a crusher that crushes a concrete lump or the like.
[0003]
The present applicant has already proposed a pressure-increasing cylinder device as described above described in Japanese Patent Publication No. 7-6524.
[0004]
As shown in FIG. 4, this pressure-increasing cylinder device includes a working hydraulic cylinder 1, a hydraulic pump 2 that supplies pressure oil to the hydraulic cylinder 1, and pressure oil discharged from the hydraulic pump 2 to the hydraulic cylinder. An operation valve 7 that selectively supplies a first passage 4 that communicates with the bottom chamber 3 and a second passage 6 that communicates with the rod chamber 5, and supplies pressurized oil to the bottom chamber 3 of the hydraulic cylinder 1. And a booster cylinder 8.
[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.
[0006]
The booster cylinder 8 has a cylinder body 10 and a pressure-increasing piston 11 incorporated therein, and the piston 11 is provided with a large diameter portion 11a and small diameter portions 11b on both sides thereof. On the other hand, the cylinder body 10 is formed with a large diameter chamber 12 for slidably guiding the large diameter portion 11a, and a first pressure increasing chamber 13a and a second pressure increasing chamber 13b for slidably guiding the small diameter portion 11b. The pressure increasing chambers 13 a and 13 b communicate with the bottom chamber 3 of the hydraulic cylinder 1 through the passage 14.
[0007]
The cylinder body 10 is formed with an import P ₁ , a pilot port P _2, and a tank port P ₃ at intervals in the moving direction of the piston 11. The import P ₁ is connected to the first passage 4 via the communication passage 15. The pilot port P ₂ communicates with the pilot chamber 21 of the switching valve 20 through the passage 16. Further, the tank port P ₃ communicates with the tank T through the passage 17.
[0008]
A circumferential groove-like switching passage 18 is provided in one small-diameter portion 11b of the piston 11 in the booster cylinder 8. When the piston 11 moves to the vicinity of the limit position of the forward stroke, the import P ₁ and the pilot The port P ₂ is communicated, and when the piston 11 moves to the vicinity of the limit position of the reverse stroke, the pilot port P ₂ and the tank port P ₃ are communicated.
[0009]
The switching valve 20 has a P port P ₁₁ , a T port P ₁₂ and A, B ports P ₁₃ and P ₁₄ , and the P port P ₁₁ communicates with the discharge port of the hydraulic pump 2 via the passage 22. The sequence valve 23 is incorporated in
[0010]
On the other hand, the T port P ₁₂ communicates with the tank T via a passage 24, and a 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 through the passage 26, and the B port P ₁₄ has the first through the passage 27. 2 It communicates with the pressurizing chamber 12b.
[0011]
Reference numeral 31 denotes a relief valve that holds the pressure oil pressure when the hydraulic cylinder 1 is extended to a set value, and reference numeral 32 denotes a relief valve that holds the pressure oil pressure when the hydraulic cylinder 1 is contracted to a set value.
[0012]
In the pressure-increasing cylinder device configured as described above, when the operation 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, and the pressure is increased. Piston A and piston rod B advance by the supply of oil.
[0013]
At this time, the oil in the rod chamber 5 of the hydraulic cylinder 1 is returned to the tank T from the second passage 6.
[0014]
Load on the piston rod B is increased, 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 to the P port P ₁₁ of the switching valve 20 from the passage 22 Inflow. 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 11 of the booster cylinder 8 Figure Move to the right side of 4 (forward movement).
[0015]
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 increase chamber 13 b, and the pressure increase oil is supplied to the bottom chamber 3 of the hydraulic cylinder 1.
[0016]
When the piston 11 moves to the vicinity of the limit position of the forward stroke, the import P ₁ of the booster cylinder 8 and the pilot port P ₂ communicate with each other via the switching passage 18, and pressure oil is supplied to the pilot chamber 21 of the switching valve 20 by the communication. The spool 28 of the switching valve 20 moves to the left in FIG. 4 against the elasticity of the spring 29 and communicates with the P port P ₁₁ and the B port P ₁₄ .
[0017]
When the switching valve 20 is switched, the pressure oil from the hydraulic pump 2 flows from the P port P ₁₁ to the B port P ₁₄ , flows into the second pressurizing chamber 12 b of the booster cylinder 8 from the passage 27, and The piston 11 moves (returns) to the left in FIG.
[0018]
By 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 increase chamber 13 a, and the pressure increase oil is supplied to the bottom chamber 3 of the hydraulic cylinder 1.
[0019]
When the piston 11 of the booster cylinder 8 moves to the vicinity of the limit position of the reverse stroke, the pilot port P ₂ and the tank port P _{3 of} the booster cylinder 8 communicate with each other, and the oil in the pilot chamber 21 of the switching valve 20 passes through the passage 16 and the switching passage. 18 and returned to the tank T flows to the passage 17, the spool 28 of the switching valve 20 is P port P ₁₁ and the a port P ₁₃ moves to the right is communicated by the elastic force of the spring 29. Since the pressure oil is supplied to the first pressurizing chamber 12a of the booster cylinder 8 by the communication, the pressure-increasing piston 11 moves forward.
[0020]
Thus, in the pressure increasing cylinder device, the pressure increasing oil is formed both when the piston 11 of the booster cylinder 8 moves forward and backward, and the pressure increasing oil is supplied to the bottom chamber 3 of the hydraulic cylinder 1. Therefore, the hydraulic cylinder 1 can be operated extremely efficiently.
[0021]
In addition, by operating the booster cylinder 8, the pressure can be increased to a pressure obtained by multiplying the area ratio m (> 1) of 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.
[0022]
[Problems to be solved by the invention]
In the pressure-intensifying cylinder device shown in FIG. 4, when the sequence valve 23 is opened by the pressure oil discharged from the hydraulic pump 2, the pressure Po on the downstream side of the sequence valve 23 increases as shown in FIG. However, the pressure at the initial stage of opening is lower than the set pressure of the sequence valve 23 and decreases to 1 / m of the set pressure of the sequence valve 23. Thereafter, as the cylinder load increases, the pressure rises, finally reaches the set pressure (Psequence) of the sequence valve 23, and after that, the fully open state is maintained, but until the fully open state is maintained. That is, when the load pressure of the hydraulic cylinder 1 operates in the range of Psequence to (Psequence × m), a pressure loss in the region indicated by the oblique lines in FIG. 5 occurs.
[0023]
Further, 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, it must be set to be equal to or lower than the set pressure of the relief valve 31. However, the higher the pressure, the higher the pressure loss.Therefore, it is necessary to keep the set pressure low, and as a result, there is a disadvantage that the pressure increasing operation is unnecessarily generated even in the pressure region where pressure increase is not required. is there.
[0024]
Further, 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 large in installation. Space is needed.
[0025]
The present invention has a technical object to suppress the occurrence of pressure loss and improve the operating efficiency of the hydraulic cylinder in the pressure-increasing cylinder device as described above.
[0026]
[Means for Solving the Problems]
In order to solve the above-described problems, in the present invention, a working hydraulic cylinder, a hydraulic pump that supplies pressure oil to the hydraulic cylinder, and a bottom chamber and a rod chamber of the hydraulic cylinder are discharged from the hydraulic pump. An operation valve that selectively supplies pressure oil, and a booster cylinder that forms pressure increase oil by reciprocating a pressure increase piston by pressure oil from the hydraulic pump and supplies the pressure increase oil to the bottom chamber of the hydraulic cylinder And a switching valve for switching and supplying the pressure oil discharged from the hydraulic pump to the chamber on the side where the piston of the booster cylinder is moved forward and the chamber on the side where the booster cylinder is moved back, and the cylinder body of the booster cylinder, The pressure boosting piston has an import that communicates with the discharge port of the hydraulic pump, a pilot port that communicates with the pilot chamber of the switching valve, and a tank port that communicates with the tank. The switch is provided with a switching passage for switching valve operation that connects the import and the pilot port near the limit position of the forward stroke of the piston and connects the import and tank port near the limit position of the return stroke. In the pressure cylinder device, a hysteresis valve is provided in a communication path that communicates the import of the booster 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. Since the import and the discharge port of the hydraulic pump communicate with each other by the opening, the open state is maintained even if the pressure drop of the communication path from the discharge port of the hydraulic pump to the import of the hysteresis valve occurs after the communication. is there.
[0027]
As described above, by installing a hysteresis valve in the communication passage that connects the booster cylinder and the discharge port of the hydraulic pump, it is possible to control only the pilot flow rate required for switching the switching valve. Even if the small flow rate is the above, the pressure is maintained until the pressure of the communication passage rises to the set pressure of the hysteresis valve. Generation of loss can be suppressed. In addition, after the hysteresis valve is opened, the pressure is increased, but the hydraulic oil supplied from the hydraulic pump to the booster cylinder is directly guided to the booster cylinder piston, so there is no loss as in the past and the hydraulic cylinder operating efficiency is improved. Can be achieved.
[0028]
Here, even if a pressure drop occurs on the import side of the hysteresis valve immediately after the hysteresis valve is opened, a method of establishing a relationship of Po ≦ Pu / m is adopted as means for holding the hysteresis valve in the opened state. be able to.
[0029]
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 of the large diameter portion and the small diameter portion of the booster piston in the booster cylinder.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.
[0031]
The same parts as those in the pressure-increasing cylinder device in FIG. 4 described above are denoted by the same reference numerals and description thereof is omitted.
[0032]
As shown in FIG. 1, a hysteresis valve 40 is incorporated in the communication passage 15 that connects the discharge port of the hydraulic pump 2 and the import P ₁ of the booster cylinder 8. As shown in FIG. 2 (I), the hysteresis valve 40 includes a spool insertion hole 42 formed of a stepped hole in the housing 41, an import 43 communicating with the small diameter hole portion 42a of the spool insertion hole 42, and a spool insertion An outport 44 communicating with the large-diameter hole portion 42b of the hole 42 is formed, and the spool 45 is slidably incorporated in the spool insertion hole 42.
[0033]
The spool 45 has a small-diameter portion 45a that is slidably supported by the small-diameter hole portion 42a, and a slidable large-diameter portion 45b is provided in the large-diameter hole portion 42b at the rear end of the small-diameter portion 45a.
[0034]
The spool 45 is pressed toward the small-diameter hole portion 42a by a spring 46 incorporated in the large-diameter hole portion 42b, thereby blocking communication between the import 43 and the outport 44.
[0035]
The small diameter portion 45a of the spool 45 is formed with an annular groove 47 and a small diameter hole 48 opened at the inner peripheral surface of the annular groove 47 and the tip surface of the small diameter portion 45a. The annular groove 47 communicates only with the import 43 in the closed position where the spool 45 blocks the communication between the import 43 and the out port 44. When the spool 45 is retracted, the annular groove 47 has an axial width that allows the import 43 and the out port 44 to communicate with each other. Have.
[0036]
The set pressure Pu of the hysteresis valve 40 configured as described above 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 / m of the previous pressure.
[0037]
Here, m represents the area ratio between the side surface of the large diameter portion 11a of the piston 11 and the end surface of the small diameter portion 11b in the booster cylinder 8.
[0038]
The hysteresis valve 40 has a return pressure Po, a return set pressure Pu by the spring 46, and a large diameter portion 11a and a small diameter portion of the piston 11 in the booster cylinder 8 so as to maintain the open state even if a pressure drop immediately after the release occurs. The relationship of Po ≦ Pu / m is established with the area ratio m of 11b.
[0039]
The pressure-increasing 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 is discharged from the first passage 4 to the hydraulic cylinder 1. Supplyed to the bottom chamber 3, the piston rod B advances.
[0040]
At this time, the switching valve 20 is in a state where the P port P ₁₁ and the A port P ₁₃ communicate with each other, and the pressure oil flowing from the hydraulic pump 2 to the passage 22 is transferred from the P port P ₁₁ to the A port P ₁₃ of the switching valve 20. The flow flows into the first pressurizing chamber 12a of the booster cylinder 8. The piston 11 moves (moves forward) in the right direction in FIG. 1 and stops due to the pressure oil flowing into the first pressurizing chamber 12 a, and the movement of the piston 11 causes the import P ₁ and the pilot port P ₂ to switch between the switching passages 18. Communicate via
[0041]
Excess oil that has flowed into the first pressurizing chamber 12 a flows into the passage 50 formed in the piston 11, passes through the check valve 51 provided in the passage 50, and flows into the first passage 4.
[0042]
When the piston 11 of the booster cylinder 8 moves forward (moves rightward in the figure), the oil in the second pressurizing chamber 12b flows from the passage 27 to the switching valve 20 and the passage 24 and is returned to the tank T.
[0043]
When a load is applied to the piston rod B of the hydraulic cylinder 1 and the load becomes higher than the set pressure Pu of the hysteresis valve 40, the spool 45 of the hysteresis valve 40 slides to the right from the state shown in FIG. As shown in FIG. 2 (II), 40 is in an open state in which the import 43 and the outport 44 communicate with each other.
[0044]
When the hysteresis valve 40 is opened, the pressure oil discharged from the hydraulic pump 2 flows into the communication passage 15 and a pressure increasing action is started. At this time, the pressure in the communication passage 15 from the discharge port of the hydraulic pump 2 to the import 43 of the hysteresis valve 40 decreases, but the hysteresis valve 40 is set to satisfy the relationship Po ≦ Pu / m. 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 where the import P ₁ and the pilot port P ₂ communicate with each other, the pressure oil supplied to the communication passage 15 is supplied from the import P ₁ to the pilot port P. flow ₂ flows into the pilot chamber 21 of the switching valve 20, by its inflow, 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).
[0045]
For this reason, 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 is supplied into the second pressurizing chamber 12 b of the booster cylinder 8. With the supply of the pressure oil, the piston 11 moves (returns) in the left direction in FIG. 3, and the oil in the first pressure increasing chamber 13a is increased. The pressurized oil is supplied from the first passage 4 to the bottom chamber 3 of the hydraulic cylinder 1.
[0046]
At this time, the pressure in the first passage 4 rises, but since the pilot check valve 9 is provided in the first passage 4, it is prevented from flowing back to the hydraulic pump 2 side.
[0047]
When the piston 11 of the booster cylinder 8 moves to the vicinity of the limit position of the reverse stroke, the pilot port P ₂ and the tank port P ₃ communicate with each other via the switching passage 18, and the switching valve 20 is connected to the spring 29 incorporated therein. The operation is switched to the state shown in FIG. 1 where the P port P ₁₁ and the A port P ₁₃ communicate with each other, and the pressure oil discharged from the hydraulic pump 2 is supplied into the first pressurizing chamber 12 a of the booster cylinder 8.
[0048]
For this reason, the piston 11 moves forward from the state shown in FIG. 1 to pressurize the oil in the second pressure increasing chamber 13 b, and the pressure increasing oil formed by the pressurization flows into the bottom chamber 3 of the hydraulic cylinder 1. .
[0049]
Thereafter, the above operation is repeated, and the pressing force for pressing the piston rod B of the hydraulic cylinder 1 gradually increases, so that the area ratio m (> 1) 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 increased to a pressure multiplied by the set pressure of the relief valve 32.
[0050]
Thus, the booster cylinder 8 increases the pressure in both the forward and backward movements of the piston 11 and supplies the increased pressure oil to the bottom chamber 3 of the hydraulic cylinder 1 so that the hydraulic cylinder 1 can be operated efficiently.
[0051]
Further, even if the pressure decreases immediately after opening, the hysteresis valve 40 maintains the open state unless the pressure drops below the return pressure Po, so that no pressure loss occurs. Immediately after the opening of the hysteresis valve 40, the booster cylinder 8 can be operated immediately, and the working efficiency can be improved.
[0052]
Further, during the pressure increasing operation, the pressure oil from the hydraulic pump 2 passes through the switching valve 20 and is sent to the booster cylinder 8 and does not need to flow through the hysteresis valve 40. A small and low-cost one can be adopted, 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. Thus, it is possible to prevent the booster cylinder 8 from being unnecessarily increased in pressure.
[0053]
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 can be reduced. it can.
[0054]
【The invention's effect】
As described above, in the present invention, a hysteresis valve that maintains an open state even if a pressure drop occurs immediately after opening is incorporated in the communication path that connects the discharge port of the hydraulic pump and the import of the booster cylinder. As a result, the occurrence of pressure loss when the booster cylinder and switching valve are operated using a sequence valve can be suppressed, and the booster cylinder operates immediately after the hysteresis valve is opened, improving the working efficiency of the hydraulic cylinder. Can be achieved.
[0055]
Further, since the hysteresis valve does not repeat the opening / closing operation like the sequence valve while maintaining the opened state immediately after being opened, stable control can be obtained and the malfunction is less likely to occur.
[0056]
Furthermore, in the case of a hysteresis valve, since the amount of oil flowing through the valve is small, the hysteresis valve can be downsized compared to 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-increasing cylinder device according to the present invention. FIG. 2 (I) is a cross-sectional view of a hysteresis valve, and (II) is a cross-sectional view showing an open state of the hysteresis valve. Pressure oil circuit diagram showing a cylinder device [FIG. 4] Pressure oil circuit diagram showing a conventional pressure-increasing cylinder device [FIG. 5] Graph showing the relationship between cylinder load and pressure of the sequence valve shown in FIG.
DESCRIPTION OF SYMBOLS 1 Hydraulic cylinder 2 Hydraulic pump 3 Bottom chamber 5 Rod chamber 7 Control valve 8 Booster cylinder 10 Cylinder main body P ₁ Import P ₂ Pilot port P ₃ Tank port 11 Piston 12a 1st pressurization chamber 12b 2nd pressurization chamber 15 Communication path 18 Switching passage 20 Switching valve 40 Hysteresis valve

Claims (2)

A hydraulic cylinder for working;
A hydraulic pump for supplying pressure oil to the hydraulic cylinder;
An operation valve for selectively supplying pressure oil discharged from a hydraulic pump to a bottom chamber and a rod chamber of the hydraulic cylinder;
A booster cylinder that reciprocates a pressure increasing piston with pressure oil from the hydraulic pump to form pressure increasing oil, and supplies the pressure increasing oil to the bottom chamber of the hydraulic cylinder;
A switching valve that supplies pressure oil discharged from the hydraulic pump to a chamber that moves the piston of the booster cylinder forward and a chamber that moves backward.
The cylinder body of the booster cylinder is provided with an import that communicates with the discharge port of the hydraulic pump, a pilot port that communicates with the pilot chamber of the switching valve, and a tank port that communicates with the tank. In the pressure increasing cylinder device provided with a switching passage for switching valve operation that connects the import port and the pilot port in the vicinity of the limit position of the forward stroke, and that connects the pilot port and the tank port in the vicinity of the limit position of the return stroke. A hysteresis valve is provided in the communication path that connects the booster cylinder import 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. The import and the discharge port of the hydraulic pump are connected, and after communication, the hydraulic pump Increasing pressure cylinder device, characterized in that the pressure drop of the communication passage extending from the discharge port to import the hysteresis valve is configured to also maintain the open state occurs. When the set pressure of the hysteresis valve is Pu, 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), the relationship of Po ≦ Pu / m is established. The pressure-increasing cylinder device according to claim 1.

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