JPH0632309Y2 - Strike number conversion device in hydraulic breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an impact number conversion device for converting the stroke number by switching the moving stroke of a piston in a hydraulic breaker applied for crushing concrete or the like. .

(Prior Art) As a conventional technology, there is, for example, Japanese Patent Publication No. 60-26939. In this publication, a flow control valve is connected in series in an oil passage between a directional switching valve and a return tank, which are alternately connected to a return oil passage and a supply oil passage, and a moving speed of a piston is adjusted by the flow control valve. A device for setting the number of hits is disclosed.

(Problems to be solved by the invention) With the above-mentioned striking number setting device, when changing the striking number of the striking device attached to the boom of a construction vehicle such as an excavator by replacing it with a bucket or the like, remote control in the cockpit There have been problems that it is difficult to change the number of hits due to, and piping of the hydraulic circuit is complicated.

The present invention aims to solve the above problems.

(Means for Solving the Problem) The device of the present invention is a valve having an internal flow path communicating with a variable pressure chamber formed in a direction control valve for changing the moving direction of a piston in a cylinder and a main pilot chamber formed in the cylinder. A body and a plurality of communication passages respectively connected to a plurality of sub-pilot chambers formed in the cylinder, and the valve body is operated to operate the internal passage and one of the communication passages.
A pilot valve that changes the moving stroke of the piston in the cylinder by communicating with two communication flow paths is provided, and the valve body is provided between the return port communicated with the return tank at the remote position and the pilot valve. A hydraulic oil flow passage for supplying pressure oil for operating the return oil is formed, and this return pipeline is opened / closed in the middle of the return pipeline connecting the return port and the return tank, and the hydraulic oil passage Is provided with an opening / closing valve for reducing the hydraulic pressure of the valve and increasing the hydraulic pressure in the hydraulic oil passage when the valve is closed to operate the valve element.

(Operation) In the striking number conversion device for the hydraulic breaker having the above-mentioned configuration, when the return pipe is opened / closed by the opening / closing valve, the hydraulic pressure in the hydraulic oil passage is switched to the reduced pressure state or the increased pressure state. When the hydraulic pressure in the hydraulic oil passage is switched to the increased pressure state, the valve element of the pilot valve operates and the internal flow path of the valve element is connected to the other communication flow path of the pilot valve, and the movement stroke of the piston is switched. The number of hits of the hydraulic breaker is converted.

(Embodiment) Next, an embodiment of the present invention will be described with reference to FIGS.

In the hydraulic breaker B, which is attached to the tip of the boom of the construction vehicle to crush concrete etc. and is used by being connected to the hydraulic power source equipped in this vehicle, the center of the cylinder 1 of the hydraulic breaker B is A shaft hole 1a is provided vertically, and a striking tool 2 and a substantially cylindrical piston 3 for striking the striking tool 2 are fitted in the shaft hole 1a so as to be slidable in the axial direction, and the cylinder 1 A gas chamber 1b is formed in which the upper end of the piston 3 is filled with nitrogen gas and the upper end of the piston 3 is projected.

In the vicinity of the central portion of the piston 3, the outer diameters of the upper portion 3a and the lower portion 3b of the piston 3 are enlarged, and the upper large diameter portion 3c and the lower large diameter portion 3d having the same outer diameter are vertically separated from each other. The large diameter portions 3c and 3d are formed in a slide hole 4 formed in a step shape with respect to the upper portion of the shaft hole 1a of the cylinder 1.
It is tightly fitted inside. The outer diameter of the upper portion 3a of the piston 3 is smaller than the outer diameter of the lower portion 3b, or is equal to the outer diameter of the lower portion 3b, and the piston 3 is provided at the upper end of the upper large diameter portion 3c.
The upper pressure receiving surface 5 for receiving the hydraulic pressure for pushing down the piston 3 is formed, while the hydraulic pressure for pushing up the piston 3 is received at the lower end of the lower large diameter portion 3d, and the area smaller than the area of the upper pressure receiving surface 5 is received. Alternatively, the lower pressure receiving surface 6 having the same area is formed.

At the upper and lower ends of the peripheral surface of the slide hole 4 of the cylinder 1, the variable pressure chamber 7 into which the high pressure oil that pressurizes the upper pressure receiving surface 5 and the high pressure oil that pressurizes the lower pressure receiving surface 6 are constantly fed. High pressure chamber 8
And are respectively recessed annularly, and slide holes 4
A low pressure chamber 9 and a main pilot chamber 10 which are communicated and blocked by the movement of the lower large-diameter portion 3d are annularly provided in the vicinity of the central portion of the peripheral surface of the annular recess. Are the first, second, and third sub-pilot chambers 11A, 11 arranged between the main pilot chamber 10 and the high-pressure chamber 8.
B and 11C are respectively provided in annular recesses and arranged in order from the top, and the gap between the outer peripheral surface of the lower portion 3b of the piston 3 and the peripheral surface of the slide hole 4 is arranged between the main pilot chamber 10 and the high pressure chamber 8. A high-pressure oil passage 13 that is opened / closed and expanded / contracted by the movement of the lower pressure-receiving surface 6 of the piston 3 is formed therein.

Further, the cylinder 1 has a variable pressure passage 1 communicating with a variable pressure chamber 7.
4 and a high-pressure flow path 15 communicating with the high-pressure chamber 8 and the accumulator 20 attached to the side surface of the cylinder 1.
And a low-pressure flow passage 16 communicating with the low-pressure chamber 9 and a pilot flow passage 17 communicating with the main pilot chamber 10 are formed facing the direction control valve 21 attached to one side surface of the cylinder 1. On the other hand, the first switching passage 18A communicating with the main pilot chamber 10, the second switching passage 18B communicating with the first auxiliary pilot chamber 11A, and the second auxiliary pilot chamber 1
A third switching passage 18C communicating with 1B and a fourth switching passage 18D communicating with the third auxiliary pilot chamber 11C are formed facing the pilot valve 40 mounted on the side surface of the cylinder 1. There is. A communication passage 12 is formed near the upper part of the cylinder 1 so as to bypass the shaft hole 1a.

In the directional control valve 21 provided for changing the moving direction of the piston 3, the plunger 23 is fitted in the plunger hole 22a formed in the valve body 22 so as to be slidable in the axial direction, and the plunger hole 22a is formed. A low pressure chamber 27 communicated with the return port 25 through the low pressure flow passage 26, a variable pressure chamber 29 communicated with the pilot flow passage 17 of the cylinder 1 through the variable pressure flow passage 28, and a return port 2
5, a low pressure chamber 30 communicated with the variable pressure passage 14, a variable pressure chamber 32 communicated with the variable pressure passage 14 via a variable pressure passage 31, and a hydraulic pump 33.
To the high pressure chamber 36, which is in communication with the high pressure passage 15 via the high pressure passage 35, and the low pressure passage 16, which is in communication with the high pressure chamber 36 via the low pressure passage 37, and the return port 2.
A low-pressure chamber 39, which communicates with the valve 5 via a low-pressure flow path 38, is formed in order from the top. Further, a communication passage 19 communicating with the communication passage 12 of the cylinder 1 and the return port 25 is formed in the upper portion of the valve body 22.

On the other hand, the plunger 23 includes an upper middle diameter portion 23b, an upper large diameter portion 23c, a small diameter portion 23d, a lower large diameter portion 23e, and a lower middle diameter portion 23f whose outer diameter is slightly larger than that of the upper middle diameter portion 23b. Are formed in order from the top, and an upper pressure receiving surface 23g that receives the hydraulic pressure of the high pressure oil in the variable pressure chamber 29 that moves the plunger 23 downward is formed on the upper end surface of the upper large diameter portion 23c. A lower pressure receiving surface 23h for receiving the hydraulic pressure of the high pressure oil in the high pressure chamber 36 for retracting the plunger 23 upward is formed on the lower end surface of the lower large diameter portion 23e, and the area of the upper pressure receiving surface 23g is the lower pressure receiving surface. It is enlarged from the area of 23h.

The pilot valve 40 selectively connects or disconnects the first switching passage 18A and the second, third, and fourth switching passages 18B, 18C, 18D so that the first switching passage 18A becomes the second switching passage. 18B, the third switching flow channel 18C, or the fourth switching flow channel 18D and the respective flow channels 18
It is connected to the cylinder 1 for changing the operation timing of the directional control valve 21 and switching the movement stroke of the piston 3 by switching to a state where it is not in communication with any of B, 18C and 18D. In the housing 41 of the pilot valve 40, a first communication channel 42A that communicates with the second switching channel 18B of the cylinder 1, a second communication channel 42B that communicates with the third switching channel 18C, and a fourth switching channel. Channel 18D
The third communication flow paths 42C that are communicated with each other are formed at positions separated by 90 °. A stepped cylindrical rotatable valve body 44 is rotatably fitted into a center hole 41a formed through the center of the housing 41, and the rotatable valve body 44 is drilled along its axial direction. A rotatable flow path (internal flow path) 45 in which an axial hole 45a that is provided and communicates with the first switching flow path 18A and a radial hole 45b that is provided along the radial direction of the axial hole 45a are connected in an L shape. Are formed.

Four interlocking pieces 43, which are slidably supported in the radial direction of the rotatable valve body 44 with respect to the outer peripheral portion of the rotatable valve body 44 and are arranged at rotationally symmetrical positions of 90 °, are outwardly extended by springs 46. It is biased toward the housing 41 so as to project into the guide hole 41b that is recessed along the outer peripheral surface of the rotatable valve body 44 with respect to the housing 41, and is elastically contacted with the peripheral surface of the guide hole 41b. For each interlocking piece 43, the tip of one interlocking piece 43 is elastically engaged with a lock hole 48 that is slightly recessed in a part of the peripheral surface of the guide hole 41b, and is forced around the axial center of the rotatable valve element 44. It is locked so that it can be pivoted.

A sliding portion 49a and a rod-shaped rod 49b are continuously provided to an operating member 49 provided to push the interlocking piece 43 to rotate the rotatable valve body 44 by 90 °. It is fitted slidably in the axial direction into a slide chamber 50 formed along the outer peripheral surface of the rotatable valve body 44 with respect to the housing 41 substantially along the tangential direction, and outwardly by a spring 51 in the slide chamber 50. While being urged, the rod 49b extends toward the tip of the facing interlocking piece 43, and each interlocking piece 43 turns 90 ° with each advancing / retreating motion of the actuating member 49, and the rotatable valve element 4 is rotated.
4 rotates 90 °.

When the rotatable valve body 44 is rotated in the A direction so that the radial hole 45b is closed by the peripheral surface of the center hole 41a of the housing 41, the rotatable flow passage 45 is blocked and the first switching flow passage 18 is opened.
A is closed, and the rotatable valve body 44 is attached to the radial hole 45b.
Is rotated in the B direction so as to be directed to the side of the first communication channel 42A, the rotation channel 45 is communicated with the first communication channel 42A and the first and second switching channels 18A, 18B are communicated with each other. When the main pilot chamber 10 and the first sub-pilot chamber 11A are communicated with each other and the rotatable valve body 44 is rotated in the C direction so that the radial hole 45b is directed to the second communication passage 42B side, the commutation is possible. The passage 45 is communicated with the second communication passage 42B, the first switching passage 18A and the third switching passage 18C are communicated with each other, the main pilot chamber 10 and the second sub pilot chamber 11B are communicated with each other, and Insert the valve body 44 into the radial hole 45b
Is rotated in the D direction so as to be directed to the side of the third communication channel 42C, the rotatable channel 45 is communicated with the third communication channel 42C and the first switching channel 18A is connected to the fourth switching channel 18D. Is connected to the main pilot chamber 10 and the third sub-pilot chamber 1
1C is communicated.

A connecting pipe 52 communicating with the outer end of the slide chamber 50 of the housing 41 is connected to the connecting passage 12 of the cylinder 1, and an operation formed by connecting both connecting passages 12 and 19 and the connecting pipe 52 in series. The oil passage 53 communicates the return port 25 of the directional control valve 21 with the slide chamber 50 of the pilot valve 40, and the pressure oil for controlling the forward / backward movement of the operating member 49 is the hydraulic oil passage 5.
3 to the pilot valve 40.

The return port 25 of the directional control valve 21 and the return tank 24 at the remote position are connected to each other in the middle of a return pipe 55, which opens and closes the return pipe 55 (two ports in this example). A two-position directional control valve) 56 is connected, and the on-off valve 56 is switched between an open state and a closed state by remote operation such as turning the switch on and off by manual operation in the cockpit of the vehicle.

When the open / close valve 56 is held open and the return pipe 55 is opened, the drain oil in the directional control valve 21 is returned to the return port 2
5 and the return line 55, and is discharged into the return tank 24, and the steady forward / backward movement of the piston 3 is repeated. On the other hand, the on-off valve 56 is switched to the closed state and the return pipe 5
When the valve 5 is closed, the pressure oil in each flow path communicating with the return port 25 is prevented from being sent into the return tank 24, and the pressure in each flow path is increased, so that the inside of the hydraulic oil passage 53 is increased. The operating member 49 of the pilot valve 40 is pressurized and the operating oil passage 5
3 is pushed by the pressure oil in 3 to move, the interlocking piece 43 is pushed to rotate the rotatable valve element 44 by 90 °, and the flow direction of the pressure oil in the pilot valve 40 is switched.

Subsequently, the operation and effect of the above-described embodiment will be described.

Now, as shown in FIG. 1, when the piston 3 is retracted to the upper end and the plunger 23 of the directional control valve 21 is advanced to the lower end, the high pressure oil flows into the high pressure passage 34, the high pressure chamber 36 and the high pressure flow. High pressure chamber 8 of cylinder 1 through passage 35 and high pressure passage 15.
While being sent into the inside, it is sent into the variable pressure chamber 7 of the cylinder 1 through the high pressure chamber 36, the variable pressure chamber 32, the variable pressure flow passage 31, and the variable pressure flow passage 14 to form the upper pressure receiving surface 5 and the lower pressure receiving surface 6. Due to the area difference and the gas pressure in the gas chamber 1b, the piston 3 moves downward and strikes the impact tool 2.

When the piston 3 moves to the lower end, the main pilot chamber 10 of the cylinder 1 communicates with the low-pressure chamber 9, so that the pressure inside the main pilot chamber 10 and the pressure-changing chamber 29 of the directional control valve 21 is reduced, so that The pressure receiving surface 23h is pushed up by the high pressure oil in the high pressure chamber 36, and the plunger 23 retracts upward.

When the plunger 23 retracts to the rising end, the directional control valve 21
Since the variable pressure chamber 32 of 3 is communicated with the low pressure chamber 30,
2 and the inside of the variable pressure chamber 7 of the cylinder 1 are decompressed, and the piston 3 starts retreating with the high pressure oil in the high pressure chamber 8 that pushes up the lower pressure receiving surface 6.

At this time, when the rotatable valve element 44 of the pilot valve 40 is rotated to the neutral position and is held in the state where the first switching passage 18A is closed (see FIG. 5), the lower pressure receiving surface 6 of the piston 3 is When displaced into the main pilot chamber 10, the high-pressure oil in the high-pressure chamber 8 passes through the high-pressure oil passage 13 and the main pilot chamber 10
Flows in, and further, the pilot flow path 17 and the variable pressure flow path 2
8 flows into the variable pressure chamber 29 of the directional control valve 21, and the plunger 23 starts to move downward by the high pressure oil in the variable pressure chamber 29 that pushes down the upper pressure-receiving surface 23g and moves to the moving end. Therefore, in this case, the lower pressure receiving surface 6 of the piston 3 is located in the high pressure chamber 8
And reciprocating between the main pilot chamber 10 and the lower pressure receiving surface 6
Is the retracted end of the piston 3, and the piston 3 repeatedly moves back and forth with the longest movement stroke 1 in which the lower receiving surface 6 moves.

Further, the actuating member 49 is actuated to rotate the rotatable valve body 44,
When the first switching flow path 18A and the second switching flow path 18B are switched to the state of being communicated with each other, the lower pressure receiving surface 6 of the piston 3 which has started to retract from the advancing end is displaced into the first sub pilot chamber 11A. At this time, the high pressure oil in the high pressure chamber 8 flows into the first sub pilot chamber 11A through the high pressure oil passage 13, and
The high-pressure oil flows into the variable pressure chamber 29 of the switching valve 21 through the switching flow channel 18B, the rotatable flow channel 45, and the first switching flow channel 18A, and the high pressure oil flows into the variable pressure chamber 29 of the switching valve 21. Start and move to the end of movement. Therefore, in this case, the time when the lower pressure receiving surface 6 of the piston 3 reciprocates between the high pressure chamber 8 and the first auxiliary pilot chamber 11A, and the lower pressure receiving surface 6 is displaced into the first auxiliary pilot chamber 11A, is the piston. 3, the piston 3 reciprocates forward and backward with an intermediate movement stroke 2 in which the lower pressure receiving surface 6 moves.

Further, when the movable valve body 44 is rotated by the actuating member 49 to switch to the state in which the first switching flow passage 18A and the third switching flow passage 18C are in communication with each other, the piston 3 that has started to retract from the advancing end. When the lower pressure receiving surface 6 of the second sub pilot chamber 11B is displaced, the high pressure oil in the high pressure chamber 8 passes through the high pressure oil passage 13
It flows into the sub pilot chamber 11B, further flows into the main pilot chamber 10 through the third switching passage 18C, the convertible passage 45, and the first switching passage 18A, and the inside of the variable pressure chamber 29 of the directional control valve 21 When the pressure becomes high, the plunger 23 is pushed down by the high pressure oil in the variable pressure chamber 29 to start moving and move to the moving end. Therefore, in this case, the lower pressure receiving surface 6 of the piston 3 reciprocates between the high pressure chamber 8 and the second auxiliary pilot chamber 11B, and the time when the lower pressure receiving surface 6 is displaced into the second auxiliary pilot chamber 11B is the piston. The piston 3 reciprocates forward and backward with an intermediate movement stroke 3 in which the lower pressure receiving surface 6 moves.

Further, when the movable valve body 44 is rotated by the actuating member 49 to switch to the state in which the first switching passage 18A and the fourth switching passage 18D are in communication with each other, the piston 3 that has started to retract from the advancing end. At the time when the lower pressure-receiving surface 6 of the second sub-pilot chamber 11C is displaced, the high-pressure oil in the high-pressure chamber 8 passes through the high-pressure oil passage 13 to the third
It flows into the sub pilot chamber 11C, further flows into the main pilot chamber 10 through the fourth switching passage 18D, the convertible passage 45, and the first switching passage 18A, and the inside of the variable pressure chamber 29 of the directional control valve 21 When the pressure becomes high, the plunger 23 is pushed down by the high pressure oil in the variable pressure chamber 29 to start moving and move to the moving end. Therefore, in this case, the time when the lower pressure receiving surface 6 of the piston 3 reciprocates between the high pressure chamber 8 and the third auxiliary pilot chamber 11C, and the lower pressure receiving surface 6 is displaced into the third auxiliary pilot chamber 11C, is the piston. The piston 3 reciprocates forward and backward with an intermediate movement stroke 4 in which the lower pressure receiving surface 6 moves.

Then, the opening / closing valve 56 is operated and controlled by an on / off operation of a switch or the like to increase or decrease the hydraulic pressure in the hydraulic oil passage 53, and the actuating member 40 is used to rotationally control the rotatable valve body 44 to move the piston 3 in four stages. Can be changed to

Therefore, the moving stroke of the piston 3 can be easily and accurately changed by a simple hydraulic circuit in which the on-off valve 56 is connected in the middle of the return pipe 55, and the hydraulic circuit for converting the number of impacts can be simplified. Therefore, there is an effect that the operation for converting the number of hits of the piston can be accurately performed by remote operation in the cockpit or the like.

A return port 25 communicating with the communication passage 12 of the cylinder 1 is provided near the upper end of the cylinder 1, and the return port 25 and the return tank 24 are communicated with each other by a return pipe line, and the hydraulic oil passage 53 is connected to the communication passage 12. It may be formed by the communication conduit 52.

In addition, the return line 5 between the return port 25 and the on-off valve 56.
Connect a pressure switch or pressure sensor to 5, and
An electromagnetic solenoid for rotating the rotatable valve body 44 of the pilot valve 40 may be provided instead of the operating member 49, and the electromagnetic solenoid may be operated and controlled by the output signal of the pressure switch or the pressure sensor.

(Effect of the Invention) Since the present invention is configured as described above, the number of hits can be easily and accurately converted by a simple hydraulic circuit, and the operation of changing the number of hits can be accurately performed by remote control. .

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and FIG. 1 is a vertical sectional view of a hydraulic breaker showing a state at the start of advancing of a piston.
FIG. 2 is a vertical cross-sectional view of the hydraulic breaker showing the state when the piston is retracted, FIG. 3 is an enlarged vertical cross-sectional view of the directional control valve, FIG. 4 is an enlarged vertical cross-sectional view of the pilot valve, and FIG. FIG. 4 is a sectional view taken along line X1-X1 and FIG. 6 is a sectional view taken along line X2-X2. 1 …… Cylinder 3 …… Piston 21 …… Direction control valve 25 …… Return port 40 …… Pilot valve 53 …… Operating oil passage 55 …… Return pipe 56 …… Opening / closing valve B …… Hydraulic breaker

Claims (1)

[Scope of utility model registration request] 1. A valve body having an internal flow path communicating with a variable pressure chamber formed in a direction control valve for changing the moving direction of a piston in a cylinder and a main pilot chamber formed in the cylinder, and a plurality of valves formed in the cylinder. A plurality of communication passages respectively communicated with the sub-pilot chambers, and by operating the valve element to communicate the internal passage with one communication passage of the respective communication passages. A pilot valve that changes the movement stroke of the piston in the cylinder is provided, and hydraulic oil that supplies pressure oil that operates the valve element is provided between the pilot valve and the return port that communicates with the remote return tank. A flow path is formed, and the return pipeline that connects the return port and the return tank is opened and closed in the middle of the return pipeline. When the return pipeline is opened, the hydraulic pressure in the hydraulic oil passage is reduced and closed. Striking number conversion device in the hydraulic breaker sometimes characterized by by boosts the oil pressure of the working oil passage provided with a closing valve for operating the valve body.