JPS60156897A - Hydraulic type impact mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to hydraulic impact mechanisms such as rock drills and breakers, and in particular to a valve chamber in which a cylindrical switching valve is fitted between a cylinder and a valve plug. A hydraulic passageway is provided between the valve chamber and the front and rear FE'4 of the cylinder to facilitate control of the dynamic characteristics of the switching valve.

[Prior art and its problems]

Conventionally, what is the method for drilling Iwatsuki and breakers ■? As shown in the AI diagram and Figure 2, inside cylinder 1, l]'l? A piston 2 having a small diameter portion is slidably fitted on the left and right sides of the figure to form a front liquid chamber 6 and a rear liquid chamber 4, and a cylindrical switching valve 5 is installed in the rear liquid chamber 4. A striking mechanism is used in which the piston 2 is slidably fitted concentrically with the piston 2, and the hydraulic pressure in the rear liquid chamber is switched between high pressure and low pressure by moving the switching valve 5 in the front-rear direction to cause the piston 2 to reciprocate.

In the striking mechanism shown in FIG. 1, the front liquid chamber 6 is constantly acted on by pressurized liquid supplied from the high pressure circuit 6. When the switching valve 5 is retracted, pressure liquid is supplied to the rear liquid chamber 4 from the high pressure circuit 6 that communicates with it, and the pressure receiving area of the piston 2 on the rear liquid chamber 4 side is equal to the pressure receiving area on the front liquid chamber 6 side. Since it is larger, the piston 1 moves forward. Immediately before the piston 2 moves forward and strikes the rod 7, the pressure liquid in the rear liquid chamber 4 passes through the rear small diameter portion 2C of the piston 2 and is introduced into the rear chamber 9 of the switching valve 5. moves forward. When the switching valve 5 moves forward, the rear liquid chamber 4 is cut off from the high pressure circuit 6 and communicated with the low pressure circuit 10, so that the pressure liquid is discharged and the screw 1 is moved back. When the piston 2 retreats, the rear surface of the large diameter portion 2a is connected to the switching valve 5.
collides with the front end of the switching valve 5, causing the switching valve 5 to retreat. When the switching valve 5 retreats, the rear liquid chamber 4 communicates with the high pressure circuit 6 again, the piston 2 moves forward, and this reciprocating motion is repeated.

However, in this type of impact mechanism, the piston 2 does not stop immediately even after the rear liquid chamber 4 communicates with the high pressure circuit 6, but continues to retreat due to inertia, and the switching valve 5 which has moved to the rear end
Since the piston was turned forward after being struck, the switching valve 5 was easily damaged, and the kinetic energy of the piston 2 when it retreated was used to remove heat from the striking, resulting in poor energy efficiency.

Therefore, in order to prevent a collision between the piston 2 and the switching valve 5, as shown in FIG. The step 2d that forms the closing liquid 11 is provided, and the switching valve 5 is moved back by the hydraulic pressure of the closing liquid chamber 11 for switching!
E-mechanism was developed. This type of striking mechanism is closed r(h
Since the switching valve 5 is moved backward through the pressure cushion of the liquid chamber 11, the piston 2 does not come into contact with the switching valve 5 at75J.

In this way, the confinement of the closed liquid chamber 11 can be determined at the time of design. However, it is difficult to predict the force applied to it, and if the retraction speed of the piston 2 is large, the retraction acceleration of the switching valve 5 becomes rapid and cannot be adjusted.
There is a risk of conflict with 2. Furthermore, since the switching valve 5 is of a type that is directly moved by the piston 2, the movement direction of the switching valve 5 is limited to only the same direction as the piston 2.

Therefore, some models use a striking mechanism in which a spool valve is provided separately from the piston as a switching valve, but this type of striking mechanism has complicated hydraulic passages, and it is difficult to arrange the hydraulic passages rationally. In addition, precision machining of the area around the piston of the cylinder and the area around the switching valve must be performed in separate processes, making manufacturing time-consuming and expensive.

[Object of the Invention 1] The present invention solves the above-mentioned problems in hydraulic impact mechanisms.

Therefore, an object of the present invention is to provide a hydraulic impact mechanism that can set an appropriate valve switching force, and also,
It is an object of the present invention to provide a hydraulic impact mechanism in which the moving direction of a switching valve provided concentrically with the piston can also be set in the opposite direction to the piston. To provide a hydraulic impact mechanism that is easy to manufacture and is inexpensive.

[Key points of the invention]

In this invention, a piston having a small diameter portion at the front and rear is slidably fitted into a cylinder, a valve plug is fitted at the rear of the cylinder to form a front liquid chamber and a rear liquid chamber, and the liquid in the rear liquid chamber is In a hydraulic impact mechanism that reciprocates a piston by switching the pressure between high pressure and low pressure with a switching valve, there is a valve chamber in which a cylindrical switching valve is slidably fitted concentrically between the outer periphery of the valve plug and the inner periphery of the cylinder. , and from the front liquid chamber and the rear liquid chamber to the valve ￥, a hydraulic pressure passage W for valve switching that opens and closes with the reciprocating movement of the piston.
19 is a hydraulic impact mechanism, and since the switching valve is not directly moved by the piston, the ψJ switching force and the moving direction can be set to C1 at the time of design.

f-Example] The invention will be described with reference to the illustrated embodiments.

FIG. 3 is a longitudinal cross-sectional view showing the structure of a hydraulic impact mechanism which is an example of the present invention, in which a piston 2 is installed in a cylinder 1 and slides in a reciprocating direction 1" rearward. One C-valve plug 12 is attached to the rear of the cylinder 1.

4 and 5 are enlarged views of the main parts thereof, with FIG. 4 showing the state in which the piston 2 is advanced, and FIG. 5 showing the state in which the piston 2 is in the retracted state. The piston 2 has a large diameter portion 2a
, the front small diameter part 2b and the rear small diameter part 2C are formed (a), and the difference in diameter forms the RN part liquid chamber 6 and the rear liquid chamber 4 -C
There is. The diameter of the rear small diameter portion 2C is four times smaller than that of the front small diameter portion 2b, and therefore, in the piston 2, the pressure receiving area on the rear liquid chamber 4 side is larger than the pressure receiving area of the front liquid chamber 31i1Q. The front liquid chamber 6 is connected to a liquid source (not shown) by a high pressure circuit B.

The valve plug 12 fitted in the rear part of the cylinder 1 has its front outer diameter reduced by 11 cm, and the outer circumference and cylinder 1
A valve chamber 17 in which the cylindrical switching valve 5 is slidably fitted concentrically with the piston 2 is formed between the piston 2 and the inner periphery of the piston 2 .

The rear liquid chamber 4 is provided with a liquid supply port 16 and a drain liquid 14 located on the Ai7 side thereof, and the liquid supply port 116 is connected to a liquid pressure source ( (not shown)
The drain 1 ] 14 is connected to a tank (not shown) by a low pressure circuit 10 via a switching valve 5 . A variable throttle 28 is provided in a passage 27 that communicates the drain fluid 014 and the low pressure circuit 10. 15.16 are high pressure and low pressure accumulators.

The switching valve 5 is slidably fitted into the valve chamber 17 with an RFIJ reverse-IJJ function, and in the reverse position, the liquid drain 1 of the rear liquid chamber 4 is
14 is provided to communicate with the low pressure circuit 10, and in the forward position, the liquid supply 16 of the rear liquid chamber 4 is communicated with the high pressure circuit 6. An inner flange 5a is provided at the front of the switching valve 5, and a switching valve front chamber 1 is provided behind the inner flange 5a.
9. and a switching valve middle chamber 20. Switching valve MiJ
A first valve switching hydraulic pressure passage 21 is provided between the chamber 19 and the rear liquid chamber 4, and is opened and closed by the large diameter portion 2a of the piston 2 as the piston 2 moves back and forth. room 20
A second valve switching hydraulic pressure passage 22 that is opened and closed by the large diameter portion 2a of the piston 2 as the piston 2 moves backward is provided between the MiJ fluid chamber 3 and the MiJ fluid chamber 3. The front liquid chamber 31+111 of the second valve switching hydraulic pressure passage 22 has a plurality of pilot ports 22a opened at an appropriate distance in the axial direction.
, 22b, 220. pylon)l]22&,
22bl: [, equipped with regulating valves 23a and 25b, which can be selectively opened and closed from the outside.

An outer flange 5b is provided at the rear of the switching valve 5, forming a switching valve rear chamber 26 at the rear. The pressure receiving area i of the switching valve rear chamber 26 is smaller than the pressure receiving area of the switching valve front chamber 19, and the pressure receiving area of the front surface of the outer flange 5b is set smaller than the pressure receiving area of the switching valve middle chamber 20.

Further, an intermediate liquid drain port 24 is provided between the front liquid chamber 6 and the rear liquid chamber 4 of the cylinder 1, and is connected to the low pressure circuit 10. Piston 2
When the piston 2 moves forward, the second valve switching hydraulic pressure passage 22 and the intermediate drain port 24 are communicated with each other, and when the piston 2 moves backward, the first valve switching hydraulic pressure passage 21 and the intermediate drain port 24 are communicated with each other. A groove 25 is provided for communicating with each other. 7 is a rod.

Next, the operation will be explained.

When the switching valve 5 is in the front, the liquid drain 114 is closed and the liquid supply 113 is opened, and both the rear liquid chamber 4 and the front liquid chamber are communicated with the high pressure circuit 6. At this time, the piston 2 Since the pressure receiving area on the rear liquid chamber 4 side is larger than the pressure receiving area on the front liquid chamber side, the piston 2 moves forward in the direction of the rod 7.The switching valve 5 moves forward because the switching valve rear chamber 26 is under high pressure. The force is maintained.

When the piston 2 advances to the position immediately before parking the rod 7, the first valve switching hydraulic pressure passage 21 opens, the rear liquid chamber 4 and the switching valve front chamber 19 communicate with each other, and the high-pressure fluid flows in front of the switching valve. It flows into chamber 19. At this time, the switching valve middle chamber 20 is connected to the second valve switching hydraulic pressure passage 22. The diameter of the groove 25° intermediate drain port 24 communicates with the low pressure circuit 1o, and the pressure receiving area of the switching valve AiJ chamber 19 is larger than the pressure receiving area of the switching valve rear chamber 26.
The switching valve 5 moves backward.

When the switching valve 5 retreats, communication between the liquid supply port 16 and the high pressure circuit 6 is cut off. Therefore, the pressure in the switching valve front chamber 19 decreases, but due to the inertia of the switching valve 5 and the action of high pressure fluid on the front surface of the outer flange 5b, it retreats to the rear end of the valve chamber 17 and completes switching. Here, the drain hole 18 of the switching valve 5 communicates the U1 liquid 14 with the low pressure circuit 1°.

The piston 2 hits the rod 7 and stops advancing R7l,
Since the pressure in the rear liquid chamber 4 is low, the vehicle starts moving backward. At this time, by adjusting the throttle amount of the iiJ variable throttle valve 28, the retraction speed of the piston 2 can be adjusted (adjustment of the number of double strokes).

When piston 2 retreats, Byron)L]22&.

22b and 220 communicate with the 611-part liquid chamber 6 in sequence.

When the large diameter portion 2a of the piston 2 passes through the pilot [] which is opened due to the selection of the regulating valves 23a and 23'u, it passes through the second valve switching hydraulic pressure passage 22 and enters the switching valve middle chamber 20. communicates with the front Rk chamber 6 and high pressure liquid flows therein.

Since the pressure receiving area of the switching valve middle chamber 20 is smaller than the pressure receiving area of the front surface of the outer flange 5b of the switching valve 5, the switching valve 5 moves forward. When the switching valve 5 is advanced, the drain 14 is cut off from communication with the low pressure circuit 10 and the fluid supply II 13 is communicated with the high pressure circuit 6. Then, the pressure in the rear liquid chamber 4 increases, the piston 2 is braked, and the backward motion energy of the piston is recovered in the form of high-pressure liquid in the accumulator 15.

When the interlocking energy of the piston 2 is recovered, the piston 2 stops retracting and enters the cutting process again, repeating the same cycle.

〔Effect of the invention〕

As described above, the fJ striking mechanism of the present invention switches the valve using the J-I force of the pressure fluid supplied through the valve switching pressure fluid passage and the difference in pressure receiving area of each chamber of the valve. Therefore, set 8
The VJ conversion power can be appropriately set at 1 o'clock. Also,
By changing the connection of the valve switching pressure fluid passage, the valve can be set to move in either the same direction as the piston or in the opposite direction. Therefore, when the moving directions of the piston and the switching valve are reversed as in the actual example, the reaction of the piston movement is offset, vibration is reduced, and impact energy transmission efficiency is improved. If there is a difference in the opening/closing function, the piston stroke can also be adjusted. Moreover, since the valve chamber can be formed simply by fitting the valve plug into the rear of the cylinder, there is no need to separately process the valve chamber for the spool valve, and the hydraulic passage can be arranged simply and rationally, making it easy to manufacture. It is cheap.

[Brief explanation of drawings]

1 and 2 are sectional views of a conventional example, and FIG. 3 is a longitudinal sectional view of the hydraulic impact mechanism of the present invention, and an enlarged longitudinal sectional view of the hydraulic impact mechanism of the present invention. In the figure, 1 is a cylinder, 2 is a piston, 6 is a front liquid chamber, 4
1 is a rear liquid chamber, 5 is a control valve, and 12 is a valve plug. Patent issuing NFI person Furukawa Mining Co., Ltd. Agent: Patent attorney Tetsuya Mori, patent attorney Yoshiaki Naito, patent attorney Shimizu, patent attorney Kajiyama Kaze

Claims (1)

[Claims] (]) A piston having small diameter portions at the front and rear is slidably fitted into the cylinder, and a valve plug is fitted at the rear of the cylinder,
In a hydraulic impact device that forms a front liquid chamber and a rear liquid chamber, and reciprocates a piston by switching the liquid pressure in the rear liquid chamber between high pressure and low pressure using a switching valve, the outer circumference of the valve plug is connected to the inner circumference of the cylinder. In between, a valve chamber is formed into which a cylindrical switching valve is slidably fitted concentrically with the piston, and a valve chamber is connected from the front liquid chamber and the rear liquid chamber.
＼, A hydraulic impact mechanism characterized by being provided with a hydraulic passage for valve switching that opens and closes as the piston reciprocates. (2) The hydraulic type according to claim 1, wherein the valve switching pressure fluid passage is connected so that the moving direction of the switching valve and the moving direction of the piston are opposite to each other.