JP2008036746A - Hydraulic hammering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic hammering device capable of improving a hammering efficiency and reducing a machining cost. <P>SOLUTION: In the hydraulic hammering device, a switching valve having a solid structure is slidably fitted in a valve chest non-coaxial to a piston. The switching valve is equipped with a valve larger diameter part, a valve smaller diameter part respectively provided at the front and rear ends of the valve larger diameter part, a valve retreat regulation part which is disposed between the valve larger diameter part and the valve smaller diameter part of the rear end and regulates the movement to rear part of the switching valve, a valve high pressure supply groove provided at the middle of the valve larger diameter part so as to communicate the rear chamber to a high-pressure circuit, and a valve scavenge groove provided between the valve larger diameter part and the valve rear end regulation part so as to communicate the rear chamber to a low pressure circuit. A valve control chamber formed at the valve smaller diameter part side of the front end of the valve chest and a valve regulation chamber formed at the valve smaller diameter part side of the rear end are partitioned in the valve chest. The valve regulation chamber is always connected to a high-pressure circuit, and the valve control chamber can be communicated by alternately switching between the high-pressure circuit and the low-pressure circuit by forward and backward movement of the piston. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydraulic striking device such as a rock drill or a breaker, and more particularly to a switching valve mechanism thereof.

As this type of hydraulic striking device, for example, the technique described in Patent Document 1 proposed by the present applicant is known.
As shown in FIG. 3, the technique described in Patent Document 1 includes a piston 51 having a large-diameter portion 51a at the center in the axial direction and small-diameter portions 51b and 51c formed before and after the large-diameter portion 51a. ing. The piston 51 is slidably fitted into the cylinder 50, so that a front chamber 52 and a rear chamber 53 are defined in the cylinder 50, respectively. The front chamber 52 is provided with a front chamber high-pressure port 58 for communicating the front chamber 52 with the high-pressure circuit 56, while the rear chamber 53 is connected to the high-pressure circuit 56 by switching the back-and-forth direction of the switching valve 54 in the rear chamber 53. A rear chamber high-pressure port 59 and a rear chamber low-pressure port 60 respectively connected to the circuit 57 are provided.

A valve plug 55 is fitted into the cylinder 50, and a valve chamber 61 concentric with the piston 51 is formed between the outer periphery of the valve plug 55 and the inner periphery of the cylinder 50. An annular switching valve 54 is slidably fitted into the valve chamber 61.
The valve chamber 61 is provided with a valve regulating chamber 67 that communicates with the high-pressure circuit 56 via the rear chamber high-pressure port 59 and urges the switching valve 54 rearward. Further, the rear end portion of the valve chamber 61 communicates with the low pressure circuit 57 via the rear chamber low pressure port 60, and the front end portion of the valve chamber 61 is always connected to the low pressure circuit 57 via the valve chamber low pressure port 61a. Communicate.

  Further, in the cylinder 50, the piston 51 is connected to a valve control chamber 65 (see FIG. 5B) for switching the switching valve 54 forward and backward, and a valve forward control port 70 connected via a valve control circuit 68. It is provided at a position that communicates with the front chamber 52 when the vehicle moves backward. The cylinder 50 is provided with a valve reverse control port 73 connected to the valve control port 64 by a valve control circuit 68 at a predetermined distance behind the valve advance control port 70. Further, the valve reverse control is provided. An oil drain port 71 that is separated from the port 73 by a predetermined distance and communicated with the low pressure circuit 57 is provided. And, when the piston 51 moves forward, an oil drain groove 72 that allows the valve reverse control port 70 and the oil drain port 71 to communicate with each other is provided on the outer periphery of the large diameter portion 51 a of the piston 51.

  According to this hydraulic striking device having such a configuration, when the switching valve 54 is in front, the rear chamber 53 is connected to the supply / discharge oil hole 66, the supply / discharge oil chamber 62, and the supply / discharge oil switching hole 63. Therefore, the rear chamber 53 and the front chamber 52 both communicate with the high voltage circuit 56. The pressure receiving area on the rear chamber 53 side of the piston 51 is larger than the pressure receiving area on the front chamber 52 side. Therefore, the piston 51 moves forward. Further, in this state, the valve advance control port 70 is opened to the front chamber 52 side, and the valve reverse control port 73 is closed by the large diameter portion 51 b of the piston 51. Therefore, the valve control chamber 65 communicating with the front chamber 52 via the valve control hole 69, the valve control port 64, and the valve control circuit 68 is at a high pressure. Therefore, both the valve regulation chamber 67 and the valve control chamber 65 are at a high pressure, and the pressure receiving area on the valve control chamber 65 side is larger than the pressure receiving area on the valve regulation chamber 67 side, so the switching valve 54 is held forward. Has been.

  Next, when the piston 51 moves forward by the above action, the valve advance control port 70 is closed at the large diameter portion 51 a of the piston 51, and the valve reverse control port 73 communicates with the oil discharge port 71 via the oil discharge groove 72. Therefore, the valve control circuit 68 and the valve control chamber 65 become low pressure. At this time, since the valve regulating chamber 67 remains at a high pressure, the switching valve 54 moves backward. When the switching valve 54 moves backward, the supply / discharge oil hole 66 communicates with the rear chamber low pressure port 60 via the supply / discharge oil switch hole 63, and the rear chamber 53 communicates with the low pressure circuit 57 via the rear chamber low pressure port 60. As a result, the forward end of the piston 51 that has moved forward strikes the rear end of the striking rod (not shown) and stops moving forward, and starts moving backward because the rear chamber 53 is at a low pressure.

  Next, when the piston 51 moves backward, the valve advance control port 70 is opened to the front chamber 52 side, and the valve reverse control port 73 is closed by the large diameter portion 51 a of the piston 51. Therefore, the valve control chamber 65 communicated with the front chamber 52 via the valve control circuit 68 becomes high pressure again, and the switching valve 54 moves forward. When the switching valve 54 moves forward, the rear chamber 53 communicates with the high-pressure circuit 56 via the rear chamber high-pressure port 59, whereby the pressure in the rear chamber 53 rises, and the piston 51 that continues to retreat due to inertia. Is subjected to braking, and the reverse kinetic energy is stored in an accumulator (not shown) in the form of high-pressure oil. Then, the piston 51 that has stopped retreating enters the forward travel again, and thereafter the same cycle is repeated.

  By the way, in this hydraulic striking device, the valve chamber 61 is formed between the outer periphery of the valve plug 55 and the inner periphery of the cylinder 50. The hydraulic oil is supplied to and discharged from the rear chamber 53 of the piston 51 through a passage (the supply / discharge oil chamber 62 and the supply / discharge oil hole 66) in the valve plug 55. Further, the switching valve 54 is basically formed in an annular shape, and a pressure receiving surface of the valve control chamber 65 is formed on the inner periphery thereof, and a pressure receiving surface of the valve regulating chamber 67 is formed on the outer periphery thereof.

  However, in the switching valve 54, as described above, the pressure receiving area on the inner peripheral side needs to be set larger than the pressure receiving area on the outer peripheral side, so that the step on the inner diameter side becomes larger. In addition to this, since the thickness of the cylindrical shape and the step on the outer diameter side are added, as a result, the switching valve 54 becomes larger in diameter as a whole. When the diameter of the switching valve 54 increases, the weight of the switching valve 54 increases and the amount of pressure oil consumed to move the switching valve 54 forward and backward increases. For this reason, the pressure oil for moving the piston 51 forward and backward decreases, so that there is a problem that the impact efficiency is lowered.

  Further, the switching valve 54 is in sliding contact with the outer diameter of the cylinder 50 and the inner diameter of the switching valve 54 and the outer diameter of the valve plug 55 are in sliding contact with each other. Each sliding contact portion is provided with a clearance. Further, the valve chamber 61 includes, from the front, a valve chamber low pressure port 61a (= low pressure), a valve control port 64 (= high pressure), a rear chamber high pressure port 59 (= high pressure), and a rear chamber low pressure port 60 (= low pressure). Although each is provided, pressure oil always leaks from the high pressure port to the adjacent low pressure port through the clearance portion. Therefore, in the switching valve mechanism in this hydraulic striking device, the pressure oil leaks at the inner and outer diameters of the valve 54, so that the amount of leakage is 2 compared to the case where the sliding contact portion has only the inner or outer diameter. Nearly double.

Here, regarding the leak amount of the pressure oil, the larger the diameter of the switching valve 54, the larger the sliding contact area, that is, the clearance amount, and the leak amount also increases. That is, in this switching valve mechanism, both the inner and outer diameters of the switching valve 54 have sliding portions, and since the switching valve 54 is large in diameter, there is a large amount of leakage of pressure oil and the impact efficiency is reduced. There is.
Further, the switching valve 54 needs to be processed by highly controlling the inner and outer diameters, the concentricity of each step, and the roundness, and the valve control hole 69 and the supply / discharge oil are formed on the side wall of the switching valve 54. Since it is necessary to provide a large number of switching holes 63, there is a problem that processing costs increase.

In view of this, the present applicant has formed a valve chamber between the valve plug and the cylinder for the purpose of improving the impact efficiency by reducing the diameter of the switching valve, and the valve plug and the switching valve are arranged non-coaxially with the piston. A switching valve mechanism for a hydraulic striking device is proposed (see, for example, Patent Document 2).
Japanese Utility Model Publication No. 61-169588 Japanese Patent Publication No. 5-16990

  However, even in the hydraulic striking device described in Patent Document 2, since the valve chamber is formed between the valve plug and the cylinder, the basic principle is that hydraulic oil is supplied to and discharged from the rear chamber through a passage in the valve plug. There is no change in configuration. Therefore, although the diameter of the switching valve mechanism has been reduced as compared with Patent Document 1, the impact efficiency resulting from the pressure oil leak from the sliding contact portion of the inner and outer diameters of the switching valve, and the inner and outer sides of the switching valve In order to solve the problem that the processing cost is increased because the diameter needs to be processed with high accuracy, there is still room for examination.

In such a hydraulic device, providing a large number of hydraulic passages in the cylinder must solve the layout restrictions, and the processing is often difficult, so reduce the hydraulic passages. Is preferred.
Therefore, the present invention has been made paying attention to such problems, and an object thereof is to provide a hydraulic striking device that has a high striking efficiency and can reduce the processing cost.

  In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention includes a piston having a large-diameter portion and small-diameter portions provided before and after the large-diameter portion, and the piston is slidably fitted therein. A cylinder in which a front chamber and a rear chamber are respectively defined in front and rear in the axial direction, a valve chamber formed non-coaxially with the piston in the cylinder, and a switching valve slidably fitted in the valve chamber, The front chamber is always connected to the high-pressure circuit, and the rear chamber is communicated by alternately switching between the high-pressure circuit and the low-pressure circuit by the back-and-forth movement of the switching valve, thereby moving the piston back and forth, A hydraulic striking device configured to be capable of striking a rod with a piston, wherein the switching valve comprises a valve large diameter portion, a valve small diameter portion provided at the front and rear ends of the valve large diameter portion, and a valve large diameter, respectively. The switching valve is arranged between the small diameter part of the valve and the rear end A valve retraction restricting portion for restricting rearward movement, a valve high pressure supply groove provided at the center of the valve large diameter portion for communicating the rear chamber and the high pressure circuit, a valve large diameter portion and a valve retraction restricting portion A valve oil drain groove provided between the rear chamber and the low-pressure circuit, wherein the valve chamber is a valve defined on the small-diameter portion side of the front end of the valve chamber. A control chamber and a valve regulating chamber defined on the small-diameter side of the rear end of the valve. The valve regulating chamber is always connected to a high-pressure circuit. It is characterized by being configured to be able to communicate by alternately switching between and.

  According to the first aspect of the present invention, the switching valve can be formed in a solid cylindrical shape having a small diameter as compared with the switching valve in each of the above-mentioned patent documents. Therefore, a small amount of hydraulic oil is required for forward / backward movement of the switching valve, so that the impact efficiency can be improved. Further, since the sliding contact portion of the switching valve has only the outer diameter and the clearance amount is small, the amount of pressure oil leakage is reduced and the impact efficiency is improved. Furthermore, since it is not necessary to machine the inner diameter and open a large number of side holes, the machining cost is reduced. In the present specification, “the switching valve has a solid structure” means that the switching valve has a structure that does not have a through hole communicating between both end faces in the axial direction.

  The invention according to claim 2 includes a piston having a large-diameter portion and small-diameter portions respectively provided before and after the large-diameter portion, and a front chamber that is slidably fitted inside the piston and is axially anteroposterior. And a cylinder in which the rear chamber is defined, a valve chamber formed non-coaxially with the piston in the cylinder, and a switching valve slidably fitted in the valve chamber, the front chamber being a high pressure circuit It is always connected, and the rear chamber is configured to be capable of striking the striking rod with the piston by moving the piston back and forth by alternately switching between the high pressure circuit and the low pressure circuit by the back and forth of the switching valve. In the hydraulic striking device, the switching valve includes a valve large diameter portion, a valve small diameter portion provided at each of the front and rear ends of the valve large diameter portion, and a valve large diameter portion and a valve small diameter portion at the rear end. A valve retraction rule placed on the , A valve high pressure supply groove provided in the center of the valve large diameter portion for communicating the rear chamber and the high pressure circuit, and a rear chamber and low pressure circuit provided between the valve large diameter portion and the valve reverse regulating portion A valve drainage groove for communicating with the valve, and a valve communication hole having one end opened on the side surface of the valve small-diameter portion at the rear end and the other end opened in the valve high-pressure supply groove and these openings communicated with each other. The valve chamber has a valve control chamber defined on the valve small-diameter portion side of the front end thereof, a valve regulation chamber defined on the valve small-diameter portion side of the rear end thereof, and The valve control chamber is configured to be able to communicate with each other by alternately switching between the high pressure circuit and the low pressure circuit by moving the piston back and forth.

  According to the second aspect of the present invention, the same effect as that of the first aspect of the invention can be obtained, and a part of the hydraulic passage on the cylinder side can be reduced. It is.

  According to the present invention, it is possible to provide a hydraulic striking device that can improve the striking efficiency and reduce the processing cost.

Embodiments of the present invention will be described below with reference to the drawings as appropriate.
FIG. 1 is a view for explaining a first embodiment of a hydraulic striking device according to the present invention.
As shown in the figure, this hydraulic striking device includes a cylinder 1 and a piston 2.

The piston 2 has a large-diameter portion 2a at the approximate center thereof, and small-diameter portions 2b and 2c are respectively provided before and after the large-diameter portion 2a. The piston 2 is slid into the cylinder 1 so that a front chamber 3 and a rear chamber 4 are defined in the cylinder 1. The front chamber 3 is always in communication with the high-pressure circuit 6 through the front chamber high-pressure port 8. On the other hand, the rear chamber 4 is provided with a rear chamber high-pressure port 9 and a rear chamber low-pressure port 10, respectively. Can communicate with the high-voltage circuit 6 and the low-voltage circuit 7 alternately.
Here, in the hydraulic striking device, a valve chamber 11 is formed in the cylinder 1 substantially in parallel with the piston 2, and the substantially solid cylindrical switching valve 5 is formed in the valve chamber 11. Is fitted.

  Specifically, the switching valve 5 is a solid cylindrical body, and has a valve large diameter portion 21 at the center in the axial direction. The diameter of the valve large diameter portion 21 can be set smaller than the diameter of the large diameter portion 2a of the piston 2 because the valve chamber 11 is provided non-coaxially with the piston 2. In the example shown in FIG. The diameter is about half of 2. Small valve diameter portions 22 and 23 are provided at the front and rear ends of the large valve diameter portion 21, respectively. On the other hand, the valve chamber 11 is partitioned by the switching valve 5 so that a valve control chamber 15 is defined at a front end portion thereof and a valve restriction chamber 16 is defined at a rear end portion thereof. The valve chamber 11 is provided with a rear chamber high pressure port 9 and a rear chamber low pressure port 10 between the valve control chamber 15 and the valve restriction chamber 16, respectively. Between the ports 10, a supply / discharge oil switching port 14 is provided.

  The small-diameter portion 22 at the front end of the switching valve 5 has a diameter that allows sliding contact with the inner diameter of the valve control chamber 15, and the small-diameter portion 23 at the rear end can slide in contact with the inner diameter of the valve regulating chamber 16. It has a diameter. Further, the diameter of the small valve diameter portion 22 at the front end is set larger than the diameter of the small valve diameter portion 23 at the rear end. That is, the pressure receiving area of the valve small-diameter portion 22 at the front end is set to be larger than the pressure receiving area of the valve small-diameter portion 23 at the rear end, and pressure is received when high-pressure oil is supplied to both the valve control chamber 15 and the valve regulating chamber 16. The switching valve 5 moves backward due to the area difference.

Further, the switching valve 5 includes a valve retraction restricting portion 26 that restricts the backward movement of the switching valve 5 between the valve large diameter portion 21 and the valve small diameter portion 23 at the rear end. . A step is provided between the valve large-diameter portion 21 of the switching valve 5 and the valve small-diameter portion 22 on the front end side, and the forward movement of the switching valve 5 can be restricted by this step.
Further, the switching valve 5 is connected to the large-diameter portion 21 of the valve via the supply / discharge oil port 12, the supply / discharge oil circuit 13, the supply / discharge oil switching port 14 and the rear chamber high-pressure port 9 when the switch valve 5 is retracted. In addition, a valve high-pressure oil supply groove 24 for communicating the rear chamber 4 and the high-pressure circuit 6 is provided. Further, between the valve large-diameter portion 21 and the valve retraction restricting portion 26, when the switching valve 5 moves forward, the supply / discharge oil port 12, the supply / discharge oil circuit 13, the supply / discharge oil switching port 14, and the rear chamber low pressure port. A valve oil drain groove 25 is provided through which the rear chamber 4 and the low pressure circuit 7 communicate with each other. A substantially conical inclined surface 27 is formed between the valve drain groove 25 and the outer diameter of the valve retraction restricting portion 26 so as to increase in diameter toward the valve retreat restricting portion 26.

  Further, on the sliding contact surface with the piston 2 in the cylinder 1, a valve control chamber 15 and a valve control circuit for switching the switching valve 5 forward and backward to a position communicating with the front chamber 3 when the piston 2 moves backward. 17 is provided with a valve advance control port 18 that is connected to the valve 17. Further, a valve reverse control port 19 connected to the valve control chamber 15 via the valve control circuit 17 is provided at a position behind that by a predetermined distance. Further, an oil discharge port 20 communicated with the low pressure circuit 7 is provided at a position separated by a predetermined distance behind the valve reverse control port 19. Further, when the piston 2 moves forward, the valve reverse control port 19 is provided. An oil drain groove 2 d that communicates with the oil drain port 20 is provided on the outer periphery of the large-diameter portion 2 a of the piston 2. The valve regulating chamber 16 is always in communication with the high-pressure circuit 6 via the high-pressure communication circuit 16a, so that the switching valve 5 can always be urged forward. Further, the valve control chamber 15 is intermittently supplied with pressure oil that urges the switching valve 5 backward as the valve control circuit 17 is alternately communicated with the high pressure circuit 6 and the low pressure circuit 7 by the forward and backward movement of the piston 2. It comes to act on.

Next, the operation and effect of this hydraulic striking device will be described.
In the hydraulic striking device having the above-described configuration, the rear chamber 4 has a supply / discharge oil port 12, a supply / discharge oil circuit 13, a supply / discharge oil switching port 14 and a rear chamber high-pressure port 9 in a state where the switching valve 5 is at the rear. Therefore, the rear chamber 4 and the front chamber 3 are both in communication with the high voltage circuit 6.

  At this time, since the pressure receiving area on the rear chamber 4 side of the piston 2 is larger than the pressure receiving area on the front chamber 3 side, the piston 2 moves forward. In this state, the valve advance control port 18 is opened to the front chamber 3 side, and the valve reverse control port 19 is closed by the large diameter portion 2a of the piston 2, so The valve control chamber 15 communicating with the chamber 3 is at a high pressure. Therefore, both the valve regulating chamber 16 and the valve control chamber 15 are at a high pressure, and the switching valve 5 is held rearward.

  Next, when the piston 2 moves forward, the valve advance control port 18 is closed at the large-diameter portion 2a of the piston 2, and the valve reverse drive control port 19 communicates with the oil discharge port 20 via the oil discharge groove 2d. 17, The valve control chamber 15 becomes a low pressure. At this time, since the valve regulating chamber 16 remains at a high pressure, the switching valve 5 moves forward. When the switching valve 5 moves forward, the rear chamber 4 communicates with the low pressure circuit 7 via the supply / discharge oil port 12, the supply / discharge oil circuit 13, the supply / discharge oil switching port 14, and the rear chamber low pressure port 10. As a result, the forward end of the piston 2 that has moved forward strikes the rear end of the striking rod R and stops moving forward, and starts moving backward because the rear chamber 4 is at a low pressure.

  Next, when the piston 2 moves backward, the valve forward control port 18 is opened to the front chamber 3 side, and the valve reverse control port 19 is closed by the large diameter portion 2a of the piston 2, so that the front chamber 3 is connected via the valve control circuit 17. The valve control chamber 15 communicated with the valve is again at a high pressure, and the switching valve 5 is retracted. When the switching valve 5 is retracted, the rear chamber 4 communicates with the high-pressure circuit 6 through the supply / discharge oil port 12, the supply / discharge oil circuit 13, the supply / discharge oil switching port 14 and the rear chamber high-pressure port 9, thereby The pressure in the rear chamber 4 rises, and the piston 2 that continues to retreat due to inertia is braked, and the retreating kinetic energy is accumulated in an accumulator (not shown) in the form of high-pressure oil. Then, the piston 2 that has stopped retreating enters the forward travel again, and thereafter the same cycle can be repeated.

  In particular, according to this hydraulic striking device, the switching valve 5 in the switching valve mechanism is configured in a solid cylindrical shape with a small diameter as compared with the switching valve in each of the above-mentioned patent documents. For this reason, the switching valve 5 can reduce the amount of hydraulic oil required for the forward and backward movement. Therefore, the impact efficiency of the hydraulic impact device can be improved. Further, since the sliding contact portion of the switching valve 5 has only the outer diameter and the clearance amount is small, the amount of pressure oil leakage can be reduced, and the impact efficiency of the hydraulic impact device can be improved. Further, since it is not necessary to cut the inner diameter and to open a large number of side holes, the processing cost can be reduced.

  Next, a second embodiment of the hydraulic striking device according to the present invention will be described. The second embodiment is different from the first embodiment described above in that a high-pressure communication circuit 16a for communicating the high-pressure circuit 6 with the valve regulating chamber 16 of the valve chamber 11 is omitted, and communication described later. The various ports between the cylinder 1 and the piston 2 and the various ports of the valve chamber 11 are the same as those in the first embodiment except that the holes 38 and 39 are opened, and the operations of the piston and the valve are the same. Since this is the same as that of the first embodiment, illustration and description thereof will be omitted as appropriate.

FIG. 2 is a view for explaining a second embodiment of the hydraulic striking device according to the present invention. In FIG. 2, an essential part of the switching valve mechanism is shown enlarged.
As shown in the drawing, the basic structure of the switching valve 30 is the same as that of the first embodiment described above. The large valve diameter portion 31 is at the center, and the small valve diameter portion 32 is provided before and after the large valve diameter portion 31. , 33, and a valve retraction restricting portion 36 for restricting rearward movement of the switching valve 30 between the valve large diameter portion 31 and the valve small diameter portion 33 at the rear end, and a communication hole 38, The part other than the part 39 is cut is basically solid. That is, the switching valve 30 has a solid structure that does not have a through hole that communicates between both end surfaces in the axial direction.

The forward movement of the switching valve 30 is restricted by a step between the valve large-diameter portion 31 and the front-end valve small-diameter portion 32. Since the valve chamber 11 is provided non-coaxially with the piston 2, the diameter of the valve large-diameter portion 31 of the switching valve 5 is smaller than the diameter of the large-diameter portion 2 a of the piston 2 as in the first embodiment described above. It can be set and has a diameter about half that of the piston 2.
The small-diameter portion 32 at the front end of the switching valve 30 is in sliding contact with the inner diameter of the valve control chamber 15, and the small-diameter portion 33 at the rear end is in sliding contact with the inner diameter of the valve regulating chamber 16. It is set larger than the diameter of the end valve small diameter portion 33. That is, since the pressure receiving area of the small diameter portion 32 at the front end is larger than the pressure receiving area of the small diameter portion 33 at the rear end, when high pressure oil is supplied to both the valve control chamber 15 and the valve regulating chamber 16, the switching valve is caused by the pressure receiving area difference. 30 can be retracted.

  The large-diameter portion 31 of the switching valve 30 is connected to the rear chamber via the supply / discharge oil port 12, the supply / discharge oil circuit 13, the supply / discharge oil switching port 14, and the rear chamber high-pressure port 9 when the switch valve 30 is retracted. 4 and a high-pressure oil supply groove 34 that communicates with the high-pressure circuit 6 is provided between the valve large-diameter portion 31 and the valve retraction restricting portion 36 when the switching valve 30 moves forward, A valve oil drain groove 35 is provided to allow the rear chamber 4 and the low pressure circuit 7 to communicate with each other via the supply / discharge oil circuit 13, the supply / drain oil switching port 14, and the rear chamber low pressure port 10. An inclined surface 37 similar to the above is formed between the valve oil drain groove 35 and the outer diameter of the valve retraction restricting portion 36.

  Further, the switching valve 30 is provided with a valve communication hole 38 that opens to the side surface of the valve small-diameter portion 33 at the rear end thereof. A valve communication hole 39 that communicates with the valve communication hole 38 and opens in the axial direction of the valve high-pressure supply groove 34 is provided. The valve restricting chamber 16 includes the valve communication holes 38 and 39 and the rear of the valve communication hole 38. It communicates with the high-pressure circuit 6 via the chamber high-pressure port 9 and always urges the switching valve 30 forward.

According to the hydraulic striking device of the second embodiment having such a configuration, the same effects as those of the first embodiment can be obtained, and, for example, compared with the configuration of the first embodiment, Since a part of the hydraulic passage can be reduced, the machining cost can be further reduced.
It should be noted that the switching valve mechanism according to the present invention and the hydraulic striking device including the same are not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. Of course.

It is a figure explaining 1st embodiment of the hydraulic striking device concerning the present invention. It is a figure explaining 2nd embodiment of the hydraulic striking device which concerns on this invention, In the same figure, the principal part of the switching valve mechanism is expanded and shown. It is explanatory drawing of the switching valve mechanism in the conventional hydraulic striking device, The figure (a) is the whole figure, The figure (b) is the elements on larger scale of the figure (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 2a Large diameter part 2b Small diameter part 2c Small diameter part 2d Oil drain groove 3 Front chamber 4 Rear chamber 5 Switching valve 6 High pressure circuit 7 Low pressure circuit 8 Front chamber high pressure port 9 Rear chamber high pressure port 10 Rear chamber low pressure port 11 Valve Chamber 12 Supply / Discharge Oil Port 13 Supply / Discharge Oil Circuit 14 Supply / Discharge Oil Switch Port 15 Valve Control Chamber 16 Valve Restriction Chamber 17 Valve Control Circuit 18 Valve Advance Control Port 19 Valve Reverse Control Port 20 Oil Discharge Port 21 Valve Large Diameter Portion 22 Valve Small diameter portion 23 Valve small diameter portion 24 Valve high pressure oil supply groove 25 Valve drain oil groove 26 Valve retraction restricting portion 27 Inclined surface 30 Switching valve 31 Valve large diameter portion 32 Valve small diameter portion 33 Valve small diameter portion 34 Valve high pressure oil supply groove 35 Valve exhaust Oil groove 36 Valve rear end restricting portion 37 Inclined surface 38 Valve communication hole 39 Valve communication hole R Rod

Claims (2)

A piston having a large-diameter portion and small-diameter portions provided before and after the large-diameter portion, and a cylinder in which a front chamber and a rear chamber are defined in front and rear in the axial direction by sliding the piston inside. A valve chamber formed non-coaxially with the piston in the cylinder, and a switching valve slidably fitted in the valve chamber, the front chamber being always connected to the high pressure circuit, and the rear chamber being the switching valve. A hydraulic striking device configured such that a piston is moved back and forth by alternately switching between a high-pressure circuit and a low-pressure circuit by forward and backward movement, and a striking rod can be hit with the piston,
The switching valve is disposed between a valve large diameter portion, a valve small diameter portion provided at each of the front and rear ends of the valve large diameter portion, and a valve large diameter portion and a valve small diameter portion at the rear end. A valve retraction restricting portion for restricting rearward movement, a valve high pressure supply groove provided at the center of the valve large diameter portion for communicating the rear chamber and the high pressure circuit, a valve large diameter portion and a valve retraction restricting portion A solid structure provided with a valve oil drain groove provided between the rear chamber and the low pressure circuit,
The valve chamber includes a valve control chamber defined on the valve small-diameter portion side of the front end thereof, and a valve restriction chamber defined on the valve small-diameter portion side of the rear end thereof, and the valve restriction chamber serves as a high-pressure circuit. A hydraulic striking device characterized in that it is always connected and the valve control chamber is configured to be able to communicate by alternately switching between a high pressure circuit and a low pressure circuit by moving the piston back and forth. A piston having a large-diameter portion and small-diameter portions provided before and after the large-diameter portion, and a cylinder in which a front chamber and a rear chamber are defined in front and rear in the axial direction by sliding the piston inside. A valve chamber formed non-coaxially with the piston in the cylinder, and a switching valve slidably fitted in the valve chamber, the front chamber being always connected to the high pressure circuit, and the rear chamber being the switching valve. A hydraulic striking device configured such that a piston is moved back and forth by alternately switching between a high-pressure circuit and a low-pressure circuit by forward and backward movement, and a striking rod can be hit with the piston,
The switching valve is disposed between a valve large diameter portion, a valve small diameter portion provided at each of the front and rear ends of the valve large diameter portion, and a valve large diameter portion and a valve small diameter portion at the rear end. A valve retraction restricting portion for restricting rearward movement, a valve high pressure supply groove provided at the center of the valve large diameter portion for communicating the rear chamber and the high pressure circuit, a valve large diameter portion and a valve retraction restricting portion A valve oil drain groove provided between the rear chamber and the low pressure circuit, and one end side opens in the side surface of the small diameter portion of the valve at the rear end and the other end side opens in the valve high pressure supply groove. A solid structure including valve communication holes communicating with each other;
The valve chamber has a valve control chamber defined on the valve small-diameter portion side of the front end thereof, and a valve regulation chamber defined on the valve small-diameter portion side of the rear end thereof. A hydraulic striking device characterized in that the high pressure circuit and the low pressure circuit are alternately switched according to the advance so that they can communicate with each other.

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