JPH0135822Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of a switching valve control device for a hydraulic impact device.

(Prior art) As shown in Fig. 1,
(Refer to No. 50191) The hydraulic impact device 1 is arranged in a cylinder body 2 and slidably within the cylinder body 2, and is attached to the front part of the cylinder body by sliding back and forth within the cylinder body 2. It is equipped with a striking piston 3 for striking a chisel (not shown) that is attached to the machine. The cylinder body 2 has a cylinder front chamber 4 and a cylinder rear chamber 5. A front chamber side oil supply passage 7 is connected to the cylinder front chamber 4 via a port 6, and a cylinder rear chamber 5 is connected to the cylinder front chamber 4 through a port 6. A rear chamber side oil supply path 9 is connected via the port 8 . The striking piston 3 has a front pressure-receiving surface 3a that receives the action of pressure oil supplied to the cylinder front chamber 4, a rear pressure-reception surface 3b that receives the action of the pressure oil supplied to the cylinder rear chamber 5, and a longitudinal direction thereof. It has an annular groove 3c provided at an intermediate position. The rear pressure receiving surface of the above-mentioned impact piston is set larger than the front pressure receiving surface,
Due to this difference in area, when pressure oil acts on both pressure receiving surfaces, the striking piston 3 is moved forward.

The rear chamber side oil supply passage 9 includes the cylinder front chamber 4.
A switching valve 10 for switching the supply of pressure oil to the cylinder rear chamber 5 is also provided. This switching valve 10 includes a valve case 13 having a valve front chamber 11 and a valve rear chamber 12, and the valve case 1.
3 and is slidably fitted into the valve front chamber 11.
The front pressure receiving surface 14 receives the pressure of the pressure oil supplied to the
a, and a rear pressure receiving surface 14b that receives the pressure of the pressure oil supplied to the valve rear chamber 12. The rear pressure receiving surface 14b of this valve body 14 is set larger than the front pressure receiving surface 14a. The valve rear chamber 12 and the cylinder front chamber 4 are communicated with each other by a pilot oil passage 16 via a port 15 formed rearward of the port 6. The cylinder body 2 further includes the port 1
A drain port 17 is formed between 5 and port 8. The drain port 17 is connected to the pilot oil passage 16 and the annular groove 3c of the striking piston 3 at the end of the backward stroke of the striking piston 3.
A pilot oil drain passage 18 for draining the pressure oil from the valve rear chamber 12 is connected through the valve rear chamber 12.

As explained above, in the hydraulic percussion device 1 incorporating the conventional switching valve 10, due to the timing relationship in each stroke of the percussion piston 3, the percussion piston 3 is not completely retracted yet at the end of the backward stroke. Since the valve rear chamber 12 is communicated with the pilot oil drain passage 18, the pressure in the valve rear chamber 12 becomes low before the striking piston 3 is completely retracted, and therefore the valve body 14 moves back and opens the rear chamber side oil supply passage 9. Therefore, pressurized oil is supplied to the cylinder rear chamber 5 via the rear chamber side oil supply passage 9.
The percussion piston 3 switches to a forward stroke. When switching to the forward stroke in this manner, the impact piston 3 closes the port 17 again, so that the pressure oil in the valve rear chamber 12 is no longer drained. Then, the valve body 14 does not retreat to the final end, but stops midway, and therefore, the forward stroke of the striking piston 3 is performed while the oil supply passage 9 is not completely opened. For the above reasons, the impact device 1 equipped with the conventional switching valve 10 has the disadvantage that its performance cannot be fully demonstrated.

(Purpose of the invention) In view of the drawbacks of conventional devices, an object of the present invention is to provide a switching valve control device that can fully demonstrate the performance of a hydraulic impact device.

(Structure of the invention) The present invention provides a switching valve control device for a hydraulic impact device configured as described above, in which an auxiliary oil drain path is provided in the valve case at a position corresponding to the stroke intermediate position of the valve body. Additionally, an oil drain relay path is formed on the outer circumferential surface of the valve body to communicate the valve rear chamber with the auxiliary oil drain path while the valve body is retracting, and the length of the oil drain relay path is equal to or greater than the impact. The valve rear chamber and the auxiliary oil drain passage are connected to each other via the oil drain relay passage so that the valve body can continue to move backward even after the piston closes the pilot oil drain passage at the beginning of its forward movement. It is characterized by being set so that communication with the user can be continued.

(Embodiment) A switching valve control device for a hydraulic impact device according to a preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 is a sectional view showing the main parts of the switching valve control device 30 according to the embodiment of the present invention. In addition,
The striking device itself has a structure similar to that shown in FIG. 1, and the switching valve control device 30 has the same overall structure as the switching valve 10 shown in FIG. The same reference numerals as those of the valve 10 are given to the parts, and the explanation thereof will be omitted.

The valve case 13 has a port 31 located at a position corresponding to the mid-stroke position of the valve body 14.
This port 31 is connected to an auxiliary oil drain passage 32 that assists the pilot oil drain passage 18 in draining oil from the rear valve chamber 12 . on the other hand,
In the valve body 14, an oil drain relay path 33 extending in the longitudinal direction is formed on a surface in sliding contact with the valve case 13. This oil drain relay passage 33 has the function of communicating the valve rear chamber 12 with the auxiliary oil drain passage 32 during the backward stroke of the valve body 14, and its length is the same as that of the striking piston 3. The length is set such that communication between the rear valve chamber 12 and the auxiliary oil drain passage 32 can be maintained even after the pilot oil drain passage 18 is closed at the beginning of its forward stroke.

(Effect of the invention) Therefore, even after the impact piston 3 closes the pilot oil drain passage 18 at the beginning of its forward stroke, the pressure oil in the valve rear chamber 12 is sent to the auxiliary drain via the oil drain relay passage 33. Since the oil continues to be drained from the oil passage 32, the valve body 14 continues its backward movement and finally retreats to its rearmost position, so that the rear chamber side oil supply passage 9 can be completely opened. In this way, sufficient pressure oil can be supplied to the cylinder rear chamber 5 via this rear chamber side oil supply path 9, so that the performance of the striking device 1 can be fully brought out. According to experiments conducted by the inventors, the impact force was 330Kg-m with the conventional device, but it was 432Kg-m with the device of the present invention, and the impact force was approximately
Improved by 30%.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a hydraulic impact device incorporating a conventional switching valve, and FIG. 2 is a sectional view showing the main parts of the switching valve control device of the present invention. 1... Hydraulic impact device, 2... Cylinder body,
3...Blow piston, 3a...Front pressure receiving surface, 3b
... Rear pressure receiving surface, 3c ... Annular groove, 4 ... Cylinder front chamber, 5 ... Cylinder rear chamber, 7 ... Front chamber oil supply path, 9 ... Rear chamber oil supply path, 30 ... Switching valve control Device, 11... Valve front chamber, 12... Valve rear chamber, 13... Valve case, 14... Valve body, 32... Auxiliary oil drain path, 33... Oil drain relay path.

Claims (1)

[Scope of utility model registration request] A cylinder body including a cylinder front chamber and a cylinder rear chamber, slidably arranged within the cylinder body,
A front pressure receiving surface receives the pressure of the pressure oil supplied to the cylinder front chamber, a rear pressure receiving surface receives the pressure of the pressure oil supplied to the cylinder rear chamber, and an annular ring provided at an intermediate position in the longitudinal direction. and a switching valve for switching the supply of pressure oil to the cylinder front chamber and the cylinder rear chamber, and the rear pressure receiving surface of the striking piston is set larger than the front pressure receiving surface, and the A front chamber side oil supply passage and a rear chamber side oil supply passage are communicated with the cylinder front chamber and cylinder rear chamber of the cylinder body, respectively.
The switching valve includes a valve case having a valve front chamber and a valve rear chamber, and a front pressure receiving surface that is slidably fitted into the valve case and receives the pressure of pressure oil supplied to the valve front chamber. , the valve body has a rear pressure receiving surface that receives the pressure of the pressure oil supplied to the rear chamber of the valve, and the rear pressure receiving surface of the valve body is set larger than the front pressure receiving surface, and the rear pressure receiving surface of the valve body is set larger than the front pressure receiving surface. The chamber and a portion rearward of the oil supply passage opening of the cylinder front chamber are communicated by a pilot oil passage, and between the opening of the pilot oil passage of the cylinder body and the opening of the rear chamber side oil supply passage. A switching valve for a hydraulic percussion device, which is provided with a pilot oil drain passage that opens to the rear of the valve and drains pressure oil from the valve rear chamber through the pilot oil passage and an annular groove of the percussion piston at the end of the retraction of the percussion piston. In the control device, an auxiliary oil drain passage is provided in the valve case that opens at a position corresponding to the stroke intermediate position of the valve body, and the valve rear chamber is formed on the outer peripheral surface of the valve body while the valve body is retracting. A drain oil relay path is formed to communicate with the auxiliary oil drain path, and the length of the drain oil relay path is
Even after the striking piston closes the pilot oil drainage passage at the beginning of its forward movement, the valve body is connected to the auxiliary oil drainage chamber via the oil drainage relay passage so that the valve body can continue its backward movement. 1. A switching valve control device for a hydraulic impact device, characterized in that the control device is configured to allow continuous communication with an oil passage.