JP2005042807A - Boost type cylinder device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and lightweight boost type cylinder device capable of reducing the number of component parts to miniaturize the device and reduce the cost. <P>SOLUTION: The boost type cylinder device comprises a booster cylinder 11 which boosts pressurized oil from a hydraulic pump 7 and feeds it to a bottom chamber 5 of a hydraulic cylinder 1, and a control valve 21 to feed the pressurized oil from the hydraulic pump 7 in a changing manner to a first pressurization chamber 16a on the returning side of a boosting piston 15 of the booster cylinder 11 and a second pressurization chamber 16b on the ongoing side, and a spool 26 for changing a flow passage of the control valve 21 is pressed against a pilot chamber 22 with a pilot plunger 32 built therein by a spring 37. A plunger chamber 39 is formed on the spring built-in side of the control valve 21, and a small plunger 40 to press the spool 26 in the same direction as the spring 37 is built in the plunger chamber 39. The plunger chamber 39 and a P-port P<SB>11</SB>to which the pressurized oil from the hydraulic pump 7 is fed communicate with each other via a communication passage 41. A throttle 43 is provided in the communication passage 41, a sequence valve which has been built in a conventional booster type cylinder device is omitted, and the booster type cylinder device is miniaturized and weight-reduced by reducing the number of component parts. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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]
When the pressure of the pressure oil supplied to the working hydraulic cylinder reaches the set pressure, the booster cylinder device operates the booster cylinder and supplies the booster oil formed by the booster cylinder to the hydraulic cylinder. ing.
[0003]
As the pressure-increasing cylinder device as described above, one described in Patent Document 1 has been conventionally known. FIG. 5 shows a case where the pressure increasing cylinder device is employed in a crusher. In this crusher, a frame 51 is rotatably attached to a bracket 50 that is detachably attached to an arm tip of a construction machine such as a hydraulic excavator, and two shafts 52 are provided on the frame 51, and each shaft 52 is centered. A pressure-increasing cylinder device 54 is provided between the upper ends of a pair of crushing arms 50a and 50b supported so as to be swingable.
[0004]
The pressure-increasing cylinder device 54 passes a hydraulic cylinder 55 for working for opening and closing the crushing arms 53a and 53b between the upper ends of the pair of crushing arms 53a and 53b, and a booster cylinder 56 is mounted on the hydraulic cylinder 55. A sequence valve 57 is attached to the outer periphery of the booster cylinder 56.
[0005]
In the pressure-intensifying cylinder device 54, the pair of crushing arms 53a and 53b are quickly swung in the direction in which the tips thereof are closed by the hydraulic cylinder 55, and the object to be crushed is sandwiched and crushed. When the object to be crushed is hard and does not break, the pressure oil pressure increases, and when the set pressure of the sequence valve 57 is reached, the booster cylinder 56 is operated to form the pressure increase oil. The material to be crushed is crushed by increasing the crushing force by the pair of crushing arms 53a and 53b.
[0006]
[Patent Document 1]
Japanese Examined Patent Publication No. 7-6524 [0007]
[Problems to be solved by the invention]
By the way, in the pressure-increasing cylinder device described in Patent Document 1, since the operation of the booster cylinder 56 is controlled by the sequence valve 57, the number of parts increases, and the connection pipe line with the sequence valve is processed. However, there are still points to be improved such as an increase in the cost, and a space for installing the sequence valve is required for the use in the crusher, and the frame 51 is increased in size and weight.
[0008]
An object of the present invention is to reduce the number of parts of a pressure-increasing cylinder device and to reduce the size and weight.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, the pressure-increasing oil is formed by moving the pressure-increasing piston by the pressure oil supplied from the hydraulic pump, and the pressure-increasing oil is supplied to the bottom chamber of the working hydraulic cylinder. Pressure oil discharged from the hydraulic pump is supplied to the booster cylinder to be supplied, the first pressurizing chamber on the side for moving the boosting piston of the booster cylinder in one direction, and the second pressurizing chamber on the side for moving in the other direction. A switching valve that is supplied by switching, and the switching valve forms a pilot chamber in which a pilot plunger for pushing the spool is incorporated on one end side of the flow path switching spool, and the spool faces the pilot chamber on the other end side. In a pressure-increasing cylinder device comprising a pilot operated switching valve provided with a spring for pressing, the switching valve passes through the pilot chamber and the second pressurizing chamber of the booster cylinder. The B port is communicated with a communication path, a throttle or check valve is provided in the communication path, a plunger chamber is formed on the other end of the spool, and the pressure receiving area in the plunger chamber is smaller than the pressure receiving area of the pilot plunger. The plunger is slidably incorporated, the plunger chamber and the P port communicating with the discharge port of the hydraulic pump are communicated with each other through a communication path, and a throttle is provided in the communication path.
[0010]
When the hydraulic pump is driven in the pressure-increasing cylinder configured as described above, the hydraulic oil is sent from the discharge port of the hydraulic pump to the hydraulic cylinder, so that the hydraulic cylinder extends.
[0011]
When a load is applied to the hydraulic cylinder, the pressure of the hydraulic oil supplied to the hydraulic cylinder increases. When the pressure exceeds the pressing force (set pressure) of the switching valve spring, the hydraulic oil supplied to the pilot chamber As a result, the pilot plunger moves, presses the spool, and operates the switching valve. The booster piston of the booster cylinder starts moving by the operation of the switching valve, and the booster cylinder starts to increase pressure.
[0012]
When the boosting piston of the booster cylinder moves (forward movement) in the direction of reducing the volume of the first pressurizing chamber, the pressure oil in the pilot chamber flows into the tank.
[0013]
On the other hand, the pressure in the plunger chamber provided in the switching valve increases, and the small plunger moves toward the spool by the pressure, and the spool moves in the direction of pressing the pilot plunger by the pressing force of the small plunger and the pressing force of the spring. To do. For this reason, the switching valve is switched in the direction in which the pressure oil of the hydraulic pump is supplied to the first pressurizing chamber of the booster cylinder, and the booster cylinder repeats the pressure increasing action.
[0014]
As described above, when the pressure of the pressure oil supplied from the hydraulic pump to the hydraulic cylinder exceeds the set pressure of the switching valve, the switching valve is operated and the booster cylinder repeats the pressure increasing action. The required sequence valve can be dispensed with. For this reason, the number of parts can be reduced, and the pressure-increasing cylinder device can be reduced in size and weight. Therefore, when it is adopted in a small crusher mounted on a mini hydraulic excavator, workability is improved and work efficiency is improved. climb.
[0015]
In the pressure-increasing cylinder device according to the present invention, if a check valve is provided in parallel with the throttle in the communication path, the pressure oil in the plunger chamber can be discharged from both the check valve and the throttle to the P port side. The switching operation can be performed smoothly.
[0016]
Further, when the plug for adjusting the elasticity of the spring is screw-engaged with the cylinder body, the set pressure of the switching valve can be adjusted. For this reason, it can be made compatible with hydraulic excavators from various manufacturers.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. As shown in FIG. 1, the pressure-increasing cylinder device is a working type in which a piston 4 having a rod 3 is slidably incorporated in a cylinder body 2 to form a bottom chamber 5 and a rod chamber 6 in the cylinder body 2. The hydraulic cylinder 1, the hydraulic pump 7 that supplies pressure oil to the hydraulic cylinder 1, the first passage 8 that communicates the pressure oil discharged from the hydraulic pump 7 to the bottom chamber 5 of the hydraulic cylinder 1, and the rod chamber 6. And a booster cylinder 11 for supplying pressurized oil to the bottom chamber 5 of the hydraulic cylinder 1.
[0018]
A pilot check valve 12 is incorporated in the first passage 8. The pilot check valve 12 returns the pressure oil in the bottom chamber 5 from the first passage 8 to the tank 13 when the operation valve 10 is switched to connect the rod chamber 6 to the discharge port of the hydraulic pump 7. .
[0019]
The booster cylinder 11 has a cylinder body 14 and a pressure-increasing piston 15 that is slidably incorporated therein. The pressure-increasing piston 15 has a large-diameter portion 15a and a pair of small-diameter portions 15b on both sides thereof. Is provided.
[0020]
On the other hand, the cylinder body 14 has a large-diameter chamber 16 that slidably guides the large-diameter portion 15a, and a first pressure-increasing chamber 17a and a second pressure-increasing chamber that slidably guide the pair of small-diameter chambers 15a and 15b. 17b is formed.
[0021]
The large-diameter chamber 16 is partitioned into a first pressurizing chamber 16a and a second pressurizing chamber 16b by the large-diameter portion 15a.
[0022]
Each of the first pressure increasing chamber 17 a and the second pressure increasing chamber 17 b communicates with the bottom chamber 5 of the hydraulic cylinder 2 through a passage 18.
[0023]
The cylinder body 14 is provided with an import P ₁ , a pilot port P _2, and a tank port P ₃ at intervals in the moving direction of the pressure increasing piston 15. The import P ₁ is connected to the first passage through the communication passage 19. 8 pilot check valves 12 communicate with the inlet side.
[0024]
The pilot port P ₂ communicates with the pilot chamber 22 of the switching valve 21 through the passage 20, and the tank port P ₃ communicates with the tank 13 through the passage 23.
[0025]
A circumferential groove-like switching passage 24 is provided in one small diameter portion 15 b of the booster piston 15 in the booster cylinder 11. The switching passage 24 allows the import P ₁ and the pilot port P ₂ to communicate with each other when the pressure-increasing piston 15 moves to the vicinity of the limit position of the return stroke in which the volume of the second pressurizing chamber 16 b is reduced. when pressure piston 15 moves to the vicinity limit position of the forward stroke, so as to communicate the pilot port P ₂ and the tank port P _3.
[0026]
As shown in FIGS. 1 and 2, the switching valve 21 has a spool 26 slidably incorporated in the valve body 25. The valve body 25 is formed with a P port P ₁₁ , a T port P ₁₂ , an A port P _13, and a B port P ₁₄ , and the P port P ₁₁ communicates with the first passage 8 through a passage 27.
[0027]
On the other hand, the T port P ₁₂ communicates with the second passage 9 through the passage 28, and a check valve 29 is incorporated in the passage 28. The A port P ₁₃ communicates with the first pressurizing chamber 16 a of the booster cylinder 11 through the passage 30, and the B port P ₁₄ communicates with the second pressurizing chamber 16 b through the passage 31.
[0028]
As shown in FIG. 2, the pilot chamber 22 is formed on one end side of the spool 26 in the valve body 25, and a pilot plunger 32 is slidably incorporated in the pilot chamber 22. The pilot chamber 22 communicates with the B port P ₁₄ via a communication passage 33 having a small passage cross-sectional area, and a check valve 34 is incorporated in the communication passage 33.
[0029]
A plug fitting hole 35 is formed in the valve body 25 on the other end side of the spool 26. A female screw 35 a is formed on the inner periphery of the opening end of the plug fitting hole 35, and a spring 37 is assembled between the tip recess of the plug 36 screwed to the female screw 35 a and the end of the spool 26.
[0030]
The spring 37 presses the spool 26 toward the pilot plunger 32, and the pressing force is adjustable by the axial movement caused by the rotation of the plug 36. The plug 36 is fixed by tightening a lock nut 38 threadedly engaged with the rear end portion.
[0031]
The plug 36 is formed with a plunger chamber 39 opened at the tip, and a small plunger 40 is slidably incorporated in the plunger chamber 39. The plunger chamber 39 communicates with the P port P ₁₁ via a communication passage 41 having a small passage cross-sectional area. A check valve 42 is provided in the communication passage 41, and a throttle 43 is provided in parallel with the check valve 42.
[0032]
Small plunger 40 is adapted to be moved by the hydraulic fluid supplied to the plunger chamber 39 via the communicating passage 41 from the P port P ₁₁ to press the spool 26. The pressure receiving area for receiving the pressure oil pressure of the small plunger 40 is smaller than the pressure receiving area for receiving the pressure oil pressure of the pilot plunger 32. Assuming that the pressure receiving area difference is S, the pressure of the pressure oil supplied to the pilot chamber 22 is P, and the pressing force of the spring 37 is F, when F = S · P, the spool 26 is held in a stopped state, and F> When S · P, the spool 26 moves toward the pilot plunger 32 due to the pressing force of the spring 37 and the pressing force of the small plunger 40, and when F <S · P, the spool 26 faces the small plunger 40. Move.
[0033]
That is, the switching valve 21 uses the pressing force of the spring 37 as a set pressure, and the spool 26 starts to move when the pressure of the pressure oil supplied to the pilot chamber 22 exceeds the set pressure.
[0034]
Here, when the spool 26 moves to the pilot plunger 32 side, the P port P ₁₁ and the A port P ₁₃ and the T port P ₁₂ and the B port P ₁₄ communicate with each other, and when the spool 26 moves to the small plunger 40 side, the P port P ₁₁ and B port P ₁₄ are communicated, and T port P ₁₂ and A port P ₁₃ are communicated via a passage 44 formed in spool 26.
[0035]
In FIG. 1, 45 indicates a relief valve that holds the pressure of the hydraulic pump 7 at the maximum extension of the hydraulic cylinder 1 at a set value, and 46 indicates the pressure of the hydraulic oil of the hydraulic pump 7 at the time of the minimum contraction of the hydraulic cylinder 1. Shows a relief valve that maintains a set value.
[0036]
The pressure-increasing cylinder device shown in the embodiment has the above structure, and its operation will be described next.
[0037]
Now, when the hydraulic pump 7 is operated and the operation valve 10 is positioned at the position a, the pressure oil discharged from the hydraulic pump 7 is supplied from the first passage 8 to the bottom chamber 5 of the hydraulic cylinder 1, and the pressure oil By supply, the piston 4 moves and the hydraulic cylinder 1 extends.
[0038]
At this time, the oil in the rod chamber 6 of the hydraulic cylinder 1 is returned from the second passage 9 to the tank 13.
[0039]
Further, the pressure oil from the hydraulic pump 7 flows from the communication passage 19 to the import P ₁ of the booster cylinder 11, flows from the import P ₁ through the switching passage 24 to the pilot port P ₂ , and further flows through the passage 20 to the switching valve. 21 into the pilot chamber 22.
[0040]
Further, pressure oil from the hydraulic pump 7 flows into the P port _{P 11} of the switching valve 21, it flows from the P port _{P 11} to the plunger chamber 39 flowing through the communication passage 41.
[0041]
As described above, the pressure oil from the hydraulic pump 7 is supplied to both the pilot chamber 22 and the plunger chamber 39 of the switching valve 21, but the pressure of the pressure oil is not applied to the piston rod 3 of the hydraulic cylinder 1. Since it is lower than the set value of the switching valve 21, the switching valve 21 does not operate.
[0042]
When a load is applied to the piston rod 3 of the hydraulic cylinder 1 and the load begins to increase, the pressure of the pressure oil discharged from the hydraulic pump 7 increases.
[0043]
When the pressure oil pressure exceeds the set value of the switching valve 21, the pilot plunger 32 presses the spool 26 with the pressure oil supplied to the pilot chamber 22. Therefore, the spool 26 moves toward the small plunger 40 against the elasticity of the spring 37.
[0044]
Here, if no check valve 34 is incorporated in the communication passage 33, and at the same time the pilot plunger 32 begins to move, to return to the tank T the pressure oil in the pilot chamber 22 flows from the communication passage 33 to the T port P ₁₂ The pilot plunger 32 cannot be moved in the direction in which the spool 26 is pressed. However, since the check valve 34 to the communication passage 33 is incorporated, it is possible to pressure oil in the pilot chamber 22 is prevented from flowing to the T port P _12, the pilot plunger 32 in a direction to press the spool 26 It can be moved reliably.
[0045]
Instead of the check valve 34, a throttle may be provided. Even in this case, the plunger 32 can be reliably moved in the direction in which the spool 26 is pressed.
[0046]
Figure 3 shows a state in which the spool 26 of the switching valve 21 is moved to the small plunger 40 side, P port _{P 11} by the movement of the spool 26 communicates with the B port _{P 14.}
For this reason, the pressure oil from the hydraulic pump 7 flows from the P port P ₁₁ to the B port P ₁₄ , flows from the B port P ₁₄ to the passage 31, and flows into the second pressurizing chamber 16 b of the booster cylinder 11. The booster piston 15 of the booster cylinder 11 moves (forwards) to the left side of the figure. At this time, since the first pressurizing chamber 16a communicates with the tank T through the passage 30, the operation of the booster cylinder 11 is performed smoothly.
[0047]
When the pressure-increasing piston 15 starts to move, the volume of the second pressurizing chamber 16b increases, so that the pressure of the pressure oil discharged from the hydraulic pump 7 decreases instantaneously and falls below the set value of the switching valve 21. The pilot plunger 32 tends to be returned by the pressing force of the spring 37 that presses the spool 26 and the pressing force of the small plunger 40, but since the throttle 43 is incorporated in the communication path 41, the pilot plunger 32 It will not be returned.
[0048]
That is, when the pilot plunger 32 is returned, it is necessary that the hydraulic pressure is smoothly fed into the plunger chamber 39 from the communication path 41 and the small plunger 40 moves in the direction of pressing the spool 26. By providing the throttle 43 in the flow passage, the flow of the pressure oil is restricted from the communication passage 41 into the plunger chamber 39 and does not flow smoothly. For this reason, even if the pressure of the pressure oil drops momentarily due to the expansion of the volume of the second pressurizing chamber 16b, the pressing force by which the small plunger 40 presses the spool 26 is not generated, and only the spring 37 pushes back the spool 26. Acts as follows. At this time, since the pressing force of the pilot plunger 32 is stronger than the elastic force of the spring 37, the pilot plunger 32 is not pushed back.
[0049]
Since the pressure drop of the pressure oil is instantaneous, and then the pressure oil pressure immediately starts to rise, the pilot plunger 32 continues to push the spool 26 and moves to the state shown in FIG.
[0050]
By the movement of the pressure-increasing piston 15, pressure-increasing oil higher in pressure than the pressure oil from the hydraulic pump 7 is formed in the first pressure-increasing chamber 17a, and the pressure-increasing oil is supplied to the bottom chamber 5 of the hydraulic cylinder 1.
[0051]
When increasing the pressure oil piston 15 is moved to the vicinity limit position of the forward stroke, closing the import P ₁ of the pressure-increasing cylinder 11 as shown in FIG. 4, communicating the pilot port P ₂ and the tank port P _3, after the communication The pressure increasing piston 15 reaches the limit position of the forward stroke.
[0052]
As shown in FIG. 4, when the pilot port P ₂ and the tank port P ₃ communicate with each other, the oil in the pilot chamber 22 of the switching valve 21 flows from the passage 20 to the pilot port P ₂ , the tank port P ₃ , the passage 23 and the second port. It flows into the passage 9 and is returned to the tank 13, so that the pressure in the pilot chamber 22 decreases. Due to the pressure drop, the spool 26 moves to the pilot plunger 32 side by the pressing force of the spring 37 and the pressing force by which the pressure oil in the plunger chamber 39 presses the small plunger 40, and the switching valve 21 is in the state shown in FIG. returning to, P port _{P 11} and the a port _{P 13} of the switching valve 21 are communicated.
[0053]
Therefore, pressure oil from the hydraulic pump 7 flows into the first pressure chamber 16a flows from the P port P ₁₁ to the A port P ₁₃ and the passage 30, the pressure-increasing piston 15 is moved to the right in FIG. 4 ( The pressure increasing oil is formed in the pressure increasing chamber 17b, and the pressure increasing oil is supplied to the bottom chamber 5 of the hydraulic cylinder 1.
[0054]
When intensifying piston 15 is moved to the vicinity limit position of the backward movement stroke, as shown in FIG. 1, and import P ₁ and the pilot port P ₂ of the booster cylinder 11 are communicated. As a result, pressure oil is supplied to the pilot chamber 22, the spool 26 of the switching valve 21 moves to the left side of the figure, and as shown in FIG. 4, the P port P ₁₁ and the B port P ₁₄ communicate with each other. The pressure oil from the hydraulic pump 7 is supplied to the second pressurizing chamber 16b of the booster cylinder 11 shown in FIG. 1, and the pressure increasing oil is formed in the first pressure increasing chamber 17a.
[0055]
When the pressure of the pressure oil discharged from the hydraulic pump 7 is higher than the set pressure of the switching valve 21, the switching operation of the switching valve 21 is repeated and the pressure increasing piston 15 of the booster cylinder 11 repeats the reciprocating motion. The pressure-increasing oil is formed both at the time and during the backward movement, and the pressure-increasing oil is supplied to the bottom chamber 5 of the hydraulic cylinder 1 so that the hydraulic cylinder 1 can be operated very efficiently.
[0056]
In addition, when a sequence valve is incorporated in the first passage as in the prior art, the pressure oil from the hydraulic pump is sent to the first pressure chamber and the second pressure chamber of the booster cylinder in a state where the flow rate is limited by the sequence valve. However, a large amount of hydraulic pressure can be supplied to the first pressurizing chamber 16a and the second pressurizing chamber 16b of the booster cylinder 11 by omitting the sequence valve.
[0057]
For this reason, the booster cylinder 11 can be operated extremely efficiently and a sequence valve is unnecessary, so that the number of parts can be reduced, and the pressure-increasing cylinder device can be reduced in size and weight.
[0058]
Further, since the elastic force of the spring 37 can be adjusted by rotating the plug 36, the set pressure of the switching valve 21 can be adjusted.
[0059]
【The invention's effect】
Since the present invention is configured as described above, it is possible to eliminate the need for the sequence valve incorporated in the conventional pressure-increasing cylinder device, so the number of parts can be reduced, and the pressure-increasing cylinder device can be reduced in size and weight. Can be achieved.
[Brief description of the drawings]
FIG. 1 is a hydraulic circuit diagram showing an embodiment of a pressure-increasing cylinder device according to the present invention. FIG. 2 is an enlarged cross-sectional view of a switching valve shown in FIG. 1. FIG. [Fig. 4] Fig. 4 is a diagram showing a state in which the pressure increasing piston of the pressure increasing cylinder device has moved to the limit position of the reciprocating stroke. [Fig. 5] Fig. 5 is a partially cutaway front view of a crusher employing a conventional pressure increasing cylinder device. Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hydraulic cylinder 5 Bottom chamber 7 Hydraulic pump 11 Booster cylinder 15 Boosting piston 16a 1st pressurization chamber 16b 2nd pressurization chamber 21 Switching valve 22 Pilot chamber 26 Spool 32 Pilot plunger 33 Communication path 34 Check valve 36 Plug 37 Spring 39 Plunger chamber 40 Small plunger 41 Communication path 42 Check valve 43 Restriction

Claims (3)

A booster cylinder is formed by moving the pressure-increasing piston by the pressure oil supplied from the hydraulic pump, and the pressure-increasing oil is supplied to the bottom chamber of the working hydraulic cylinder, and the pressure-increasing piston of the booster cylinder. A switching valve that switches and supplies the pressure oil discharged from the hydraulic pump to the first pressurizing chamber that is moved in one direction and the second pressurizing chamber that is moved in the other direction. The pilot switching valve is provided with a pilot chamber in which a pilot plunger for spool pressing is incorporated at one end of the flow path switching spool, and a spring for pressing the spool toward the pilot chamber at the other end. In the pressure type cylinder device, the pilot valve and the B port passing through the second pressurizing chamber of the booster cylinder are communicated with the switching valve through a communication path, and the communication path is throttled. Is provided with a check valve, a plunger chamber is formed on the other end of the spool, a small plunger having a pressure receiving area smaller than the pressure receiving area of the pilot plunger is slidably incorporated in the plunger chamber, and the plunger chamber and the hydraulic pump are discharged. A pressure-increasing cylinder device characterized in that a P port communicating with an outlet communicates with a communicating path, and a throttle is provided in the communicating path. The pressure-increasing cylinder device according to claim 1, wherein a check valve is provided in parallel with the throttle in the communication path. The pressure-intensifying cylinder device according to claim 1 or 2, wherein a plug for adjusting spring elasticity is screw-engaged with the cylinder body.

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