JP2015163426A - Hydraulic striking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic striking device that can stabilize striking performance.SOLUTION: In the hydraulic striking device, a change-over valve mechanism 210 includes: valve energization means for constantly energizing a valve 300 in a direction; and valve regulating means for moving the valve 300 in an opposite direction while resisting energization force of the valve energization means during hydraulic oil supply. An accumulator 400 is provided between a channel for supplying hydraulic oil to the valve regulating means and the valve energization means and a channel for supplying hydraulic oil to a piston rear chamber 111.

Description

  The present invention relates to a hydraulic striking device such as a rock drill or a breaker.

  In the hydraulic striking device, increasing the number of striking is performed as one measure for obtaining high output, that is, a strong striking force. In order to achieve a high striking number, a striking system (hereinafter referred to as “piston front / rear chamber high / low pressure switching type) that controls the working pressure oil so that the front chamber and rear chamber of the piston are alternately switched to a high pressure circuit and a low pressure circuit. Is also effective. That is, if the piston front / rear chamber high-low pressure switching type hydraulic striking device is used, the hydraulic fluid on the front chamber side does not resist the movement of the piston in the striking direction. Therefore, it is suitable for realizing a high hitting number.

  Here, as this type of hydraulic striking device, for example, a technique described in Patent Document 1 is disclosed. The piston front / rear chamber high / low pressure switching striking device described in the same document includes a large-diameter portion 521, 522 at the center in the axial direction and a small-diameter portion formed before and after the large-diameter portion, as shown schematically in FIG. And a piston 520 having 523 and 524. The piston 520 is slidably fitted into the cylinder 500, whereby a piston front chamber 501 and a piston rear chamber 502 are defined in the cylinder 500, respectively. An oil drain groove 525 is formed in the center of the piston large diameter portions 521 and 522. In the present specification, the striking direction (left direction in the figure) is defined as “front”.

  Connected to the piston front chamber 501 is a piston front chamber passage 506 that allows the piston front chamber 501 to communicate with the high pressure circuit 538 and the low pressure circuit 539 by forward / backward switching of a valve 526 described later. On the other hand, a piston rear chamber passage 507 is connected to the piston rear chamber 502 to connect the piston rear chamber 502 to the high pressure circuit 538 and the low pressure circuit 539 by switching the valve 526 forward and backward. The high voltage circuit 538 is provided with a high pressure accumulator 540, and the low voltage circuit 539 is provided with a low pressure accumulator 543.

  A piston advance control port 503 is provided behind the piston front chamber 501 at a predetermined interval, and a piston reverse control port 504 is provided at a predetermined interval in front of the piston rear chamber 502. The piston advance control port 503 has two openings for normal stroke and short stroke, and the piston advance control port 503a on the piston front chamber 501 side is for short stroke with a variable throttle. is there. In this specification, the normal stroke setting, that is, the variable throttle is fully closed and the piston advance control port 503 on the piston rear chamber 502 side operates will be described.

  A piston retraction control interlocking port 508 is provided behind the piston advance control port 503 at a predetermined interval. Further, a piston advance control interlocking port 509 is provided in front of the piston retreat control port 504 with a predetermined interval. Between the piston reverse control interlocking port 508 and the piston advance control interlocking port 509, an oil discharge port 505 is provided with a predetermined distance therebetween. Further, the piston advance control port 503 and the piston retraction control interlocking port 508 are communicated with each other by a valve rear chamber 511 and a valve control passage 518, which will be described later, and the piston retraction control port 504 and the piston advance control interlocking port 509 are described later. The front chamber 510 communicates with the valve control passage 517.

  Further, a valve chamber 541 is formed in the cylinder 500 non-coaxially with the piston 520, and a valve 526 is slidably fitted in the valve chamber 541. In the valve chamber 541, a valve front chamber 510, a valve retraction holding chamber 515, a main chamber 542, a valve advance holding chamber 516, and a valve rear chamber 511 are formed by an annular step in order from the front to the rear. . The main chamber 542 is provided with a piston front chamber low pressure port 512, a piston high pressure port 514, and a piston rear chamber low pressure port 513 spaced apart from each other by a predetermined distance from the front to the rear. A piston front chamber passage 506 is connected between the piston front chamber low pressure port 512 and the piston high pressure port 514, and a piston rear chamber passage 507 is connected between the piston high pressure port 514 and the piston rear chamber low pressure port 513. Has been.

  The valve 526 includes large-diameter portions 527, 528, and 529, medium-diameter portions 530 and 531 provided in front and rear thereof, a small-diameter portion 532 provided in front of the medium-diameter portion 530, and a rear side of the medium-diameter portion 531 A solid valve body (spool) having a small-diameter portion 533 provided on the surface. A piston front chamber switching groove 534 is annularly provided between the large diameter portion 527 and the large diameter portion 528, and a piston rear chamber switching groove 535 is annular between the large diameter portion 528 and the large diameter portion 529. Is provided. The small diameter portion 532 and the piston front chamber switching groove 534 are in communication with each other through a communication passage 536, and the small diameter portion 533 and the piston rear chamber switching groove 535 are in communication with each other through a communication passage 537.

  The valve 526 has a small-diameter portion 532 positioned in the valve front chamber 510 with respect to the valve chamber 541, an intermediate-diameter portion 530 positioned in the valve receding holding chamber 515, and large-diameter portions 527, 528, and 529 in the main chamber 542. It is slidably fitted so that the medium diameter portion 531 is located in the valve advance holding chamber 516 and the small diameter portion 533 is located in the valve rear chamber 511. When the valve 526 performs the forward / backward movement, the large diameter portion 527 opens and closes the piston front chamber low pressure port 512, and the large diameter portion 528 communicates / closes the piston front chamber passage 506 and the piston high pressure port 514 at the same time as the piston rear chamber. The passage 507 and the piston high pressure port 514 are closed / communicated, and the large diameter portion 529 opens and closes the piston rear chamber low pressure port 513.

  When the piston front chamber passage 506 communicates with the piston high pressure port 514, the valve receding holding chamber 515 becomes high pressure. Conversely, when the piston rear chamber passage 507 communicates with the piston high pressure port 514, the valve advance holding chamber 516 becomes high pressure. Here, the pressure receiving area of the valve front chamber 510 is set larger than the pressure receiving area of the valve advance holding chamber 516. Similarly, the pressure receiving area of the valve rear chamber 511 is set larger than the pressure receiving area of the valve receding holding chamber 515.

Next, the operation of the above-described hydraulic striking device will be described with reference to FIG. In FIG. 10, the passage in the high pressure state is indicated by “shaded”.
Now, when the valve 526 is switched to the forward position, the piston high pressure port 514 and the piston rear chamber passage 507 communicate with each other and the piston rear chamber 502 becomes high pressure. On the other hand, since the piston front chamber low pressure port 512 and the piston front chamber passage 506 communicate with each other and the piston front chamber 501 is at a low pressure, the piston 524 moves forward. At this time, although both the valve front chamber 510 and the valve rear chamber 511 are at a low pressure, the valve advance holding chamber 516 is at a high pressure, and the valve 526 is held at the advanced position (see FIG. 10A).

  Next, when the piston 524 moves forward and the piston retraction control port 504 and the piston rear chamber 502 communicate with each other, the valve front chamber 510 becomes high pressure. Here, since the pressure receiving area of the valve front chamber 510 is larger than the pressure receiving area of the valve advance holding chamber 516, the valve 526 starts to move backward. At this time, the valve rear chamber 511 communicates with the low pressure circuit 539 via the valve control passage 518, the piston retraction control interlocking port 508, and the oil discharge port 505, so that the valve 526 can be retreated without any problem (see FIG. 10 (b)).

  In the reverse phase of the valve 526 shown in FIG. 10B, assuming a hydraulic circuit in which the piston reverse control interlocking port 508 does not exist, the piston advance control port 503 is closed by the piston large diameter portion 521. Therefore, the valve rear chamber 511 and the valve control passage 518 become a closed circuit, and the valve 526 cannot be moved backward. That is, when the valve front chamber 510 communicates with the high pressure circuit 538 via the piston reverse control port 504 and the piston rear chamber 502, the valve rear chamber 511 is connected to the oil discharge port 505 in order to ensure the reverse operation of the valve 526. It can be seen that the piston retraction control interlocking port 508 communicating with the low-pressure circuit 539 via this is essential.

  Immediately after the piston 520 reaches the strike point, the valve 526 is completely switched to its retracted position. In the valve retracted position, the piston front chamber 501 communicates with the piston high pressure port 514 and the piston front chamber 501 becomes high pressure, and the piston rear chamber 502 communicates with the piston rear chamber low pressure port 513 and the piston rear chamber 502 becomes low pressure. As a result, the piston 520 turns backward. Although both the valve front chamber 510 and the valve rear chamber 511 are at a low pressure, the valve retraction holding chamber 515 is at a high pressure, and the valve 526 is held at the retreat position (see FIG. 10C).

  When the piston 520 retreats and the piston advance control port 503 communicates with the piston front chamber 501, the valve rear chamber 511 becomes high pressure, and the pressure receiving area of the valve rear chamber 511 is larger than the pressure receiving area of the valve retraction holding chamber 515. Start moving forward. At this time, the valve front chamber 510 communicates with the low pressure circuit 539 via the valve control passage 517, the piston advance control interlocking port 509, and the oil discharge port 505, so that the valve 526 can advance without any problem ( (Refer FIG.10 (d)). Then, the valve 526 is switched to the forward position again, and the above cycle is repeated to perform a hit.

  In the forward phase of the valve 526 shown in FIG. 10D, assuming a hydraulic circuit in which the piston advance control interlocking port 509 does not exist, the piston retraction control port 504 is blocked by the piston large diameter portion 522. Therefore, the valve front chamber 510 and the valve control passage 517 are closed, and the valve 526 cannot move forward. That is, when the valve rear chamber 511 communicates with the high pressure circuit 538 via the piston advance control port 503 and the piston front chamber 501, the valve front chamber 510 is connected to the oil discharge port 505 in order to ensure the forward operation of the valve 526. It can be seen that the piston forward control interlocking port 509 communicating with the low pressure circuit 539 is essential.

Japanese Patent Laid-Open No. 46-1590 Japanese Utility Model Publication No. 61-169588 (FIG. 1)

By the way, the present inventors have developed a piston front / rear chamber high / low pressure switching type aiming at higher output of the hydraulic striking device, but in the conventional piston front / rear chamber high / low pressure switching type hydraulic striking device, During the development process, it was found that there were harmful effects caused by the high number of hits.
That is, in this type of striking device, the supply source and collection destination of the pressure oil are a pump and a tank provided in the carriage, and each is connected to the cylinder as a high pressure circuit and a low pressure circuit via a hydraulic hose (or hydraulic piping). Connected. The high pressure circuit is provided with a high pressure accumulator mainly for the purpose of stabilizing the impact performance by compensating the pressure and flow rate in the high pressure circuit. The low-pressure circuit is provided with a low-pressure accumulator mainly for the purpose of absorbing the impact of the back pressure in the low-pressure circuit and preventing the hose fitting from being damaged. In general, the high-pressure accumulator and the low-pressure accumulator are provided in the vicinity of the hydraulic hose connection portion of the cylinder because of the purpose and layout restrictions (see, for example, FIG. 1 of Patent Document 2).

  Here, in the hydraulic striking device described above, when the piston 520 strikes the rod (between (b) to (c) in FIG. 10), the piston 520 suddenly stops in the rear chamber 502, so-called water Impact is generated in the pressure oil by the impact action (water hammer). At this time, since the valve 520 does not reach the rear end stroke completely, the impact of the pressure oil propagates to all the passages connected to the high pressure. At this time, the valve front chamber 510 is connected to a high pressure and is in the process of retreating. However, if the impact of the pressure oil is transmitted to the valve front chamber 510, the behavior of the valve 520 may become unstable.

However, in the conventional hydraulic striking device, as described above, the high-pressure accumulator 540 is disposed near the connection between the high-pressure circuit 538 and the hose for the purpose of pressure / flow rate compensation in the circuit. In other words, the high-pressure accumulator 540 is disposed farthest from the valve front chamber 510 in a path and at a location sandwiching the impact occurrence location. Therefore, there is a problem that the impact of the pressure oil propagating from the piston rear chamber 502 to the valve front chamber 510 can hardly be buffered.
In particular, since the hydraulic striking device of the piston front / rear chamber high / low pressure switching type has a high striking number, the unstable valve behavior becomes an impediment to exhibiting stable striking performance.
Accordingly, the present invention has been made paying attention to such problems, and an object thereof is to provide a hydraulic striking device capable of stabilizing the striking performance.

  In order to solve the above problems, a hydraulic striking device according to a first aspect of the present invention includes a cylinder, a piston slidably fitted in the cylinder, an outer peripheral surface of the piston, and an inner peripheral surface of the cylinder. A piston front chamber and a piston rear chamber which are defined between the piston front chamber and the piston rear chamber, and a switching valve mechanism which switches the piston front chamber and the piston rear chamber alternately between a high pressure circuit and a low pressure circuit; A hydraulic striking device for striking a striking rod by moving the piston back and forth in the cylinder, wherein the piston has a large diameter portion and a small diameter provided respectively in front of and behind the large diameter portion. And a valve switching groove formed at substantially the center in the axial direction of the large-diameter portion, the cylinder has a plurality of control ports, and the switching valve mechanism includes the piston in the cylinder. Is formed non-coaxial A valve chamber to which the plurality of control ports are connected, a valve slidably fitted in the valve chamber, a valve urging means for constantly urging the valve in one direction in the forward / backward direction, and pressure oil When supplied, valve control means for moving the valve in the opposite direction against the biasing force of the valve biasing means, a path for supplying pressure oil to the valve control means, and pressure oil to the piston rear chamber And an accumulator provided between the control valve and the switching valve mechanism, wherein the plurality of control ports communicate with each other in a predetermined manner according to the back-and-forth movement of the valve switching groove by the forward and backward movement of the piston. As a result, the pressure oil is supplied to and discharged from the valve control means to move the valve forward and backward, and the piston front chamber and the piston rear chamber are alternately switched between the high pressure circuit and the low pressure circuit in accordance with the forward and backward movement of the valve. The Characterized in that for supplying and discharging hydraulic oil to advance and retract tons is repeated.

  According to the hydraulic striking device according to the first aspect of the present invention, the switching valve mechanism is configured such that the plurality of control ports communicate with each other in a predetermined manner according to the back-and-forth movement of the valve switching groove caused by the forward and backward movement of the piston. The pressure oil is supplied to and discharged from the means, and the valve is moved forward and backward, and the piston front chamber and the piston rear chamber are alternately switched between the high pressure circuit and the low pressure circuit according to the forward and backward movement of the valve, and the forward and backward movement of the piston is repeated. Since the hydraulic oil is supplied and discharged as described above, the striking efficiency can be improved by the striking of the piston front and rear chamber high / low pressure switching type.

  According to the switching valve mechanism of the hydraulic striking device according to the first aspect of the present invention, the accumulator is provided between the path for supplying the pressure oil to the valve control means and the path for supplying the pressure oil to the piston rear chamber. Since it is provided, the impact of the pressure oil generated in the piston rear chamber is buffered by the accumulator. Therefore, the impact of pressure oil is not transmitted to the valve control means. Therefore, the behavior of the valve is not disturbed and the hitting performance is stabilized.

  Here, in the hydraulic striking device according to the first aspect of the present invention, an accumulator is provided between a path for supplying pressure oil to the valve urging means and a path for supplying pressure oil to the piston rear chamber. Is preferred. With such a configuration, the hydraulic path for driving the valve and the piston rear chamber are completely cut off by a hydraulic circuit, which is more preferable for further stabilizing the impact performance.

  In order to solve the above-described problem, a hydraulic striking device according to a second aspect of the present invention includes a cylinder, a piston slidably fitted in the cylinder, an outer peripheral surface of the piston, and an inside of the cylinder. The piston front chamber and piston rear chamber, which are defined between the circumferential surface and spaced apart in the axial direction, are always connected to the piston front chamber at high pressure, and the piston rear chamber is alternately used as a high pressure circuit and a low pressure circuit. A hydraulic valve striking device for striking a striking rod by moving the piston back and forth in the cylinder, wherein the switching valve mechanism is a part of the piston in the cylinder. When a valve chamber formed non-coaxially, a valve slidably fitted in the valve chamber, a valve urging means for constantly urging the valve in one direction in the forward / backward direction, and pressure oil are supplied Of the valve biasing means A valve control means for moving the valve in the opposite direction against the force; an accumulator provided between a path for supplying pressure oil to the piston rear chamber; the valve urging means; and the valve control means; The switching valve mechanism supplies and discharges pressure oil to and from the valve control means according to the forward and backward movement of the piston, and moves the valve forward and backward, and the piston rear chamber according to the forward and backward movement of the valve. Are alternately switched to a high-pressure circuit and a low-pressure circuit, and hydraulic oil is supplied and discharged so that the forward and backward movements of the piston are repeated.

  According to the hydraulic striking device according to the second aspect of the present invention, the switching valve mechanism feeds and discharges the pressure oil to the valve control means according to the forward and backward movement of the piston, and moves the valve forward and backward. The piston rear chamber is alternately switched between the high pressure circuit and the low pressure circuit according to the forward / backward movement, and hydraulic oil is supplied and discharged so that the piston moves forward and backward repeatedly. Can do.

  According to the switching valve mechanism of the hydraulic striking device according to the second aspect of the present invention, the path for supplying pressure oil to the valve urging means and the valve control means, and the path for supplying pressure oil to the piston rear chamber, Since the accumulator is provided in between, the impact of the pressure oil generated in the piston rear chamber is buffered by the accumulator. Therefore, the impact of pressure oil is not transmitted to the valve urging means and the valve control means. Therefore, the behavior of the valve is not disturbed and the hitting performance is stabilized.

  In order to solve the above-described problem, a hydraulic striking device according to a third aspect of the present invention includes a cylinder, a piston slidably fitted in the cylinder, an outer peripheral surface of the piston, and an inner portion of the cylinder. The piston front chamber and piston rear chamber, which are defined between the circumferential surface and spaced apart in the axial direction, are always connected to the piston rear chamber at high pressure, and the piston front chamber is alternately used as a high pressure circuit and a low pressure circuit. A hydraulic valve striking device for striking a striking rod by moving the piston back and forth in the cylinder, wherein the switching valve mechanism is a part of the piston in the cylinder. When a valve chamber formed non-coaxially, a valve slidably fitted in the valve chamber, a valve urging means for constantly urging the valve in one direction in the forward / backward direction, and pressure oil are supplied Of the valve biasing means A valve control means for moving the valve in the opposite direction against the force; an accumulator provided between a path for supplying pressure oil to the piston rear chamber; the valve urging means; and the valve control means; The switching valve mechanism supplies and discharges pressure oil to and from the valve control means according to the forward and backward movement of the piston, and moves the valve forward and backward, and the piston front chamber according to the forward and backward movement of the valve. Are alternately switched to a high-pressure circuit and a low-pressure circuit, and hydraulic oil is supplied and discharged so that the forward and backward movements of the piston are repeated.

  According to the switching valve mechanism of the hydraulic striking device according to the third aspect of the present invention, between the path for supplying pressure oil to the valve urging means and the valve control means and the path for supplying pressure oil to the piston rear chamber. Since the accumulator is provided, the impact of the pressure oil generated in the piston rear chamber is buffered by the accumulator. Therefore, the impact of pressure oil is not transmitted to the valve urging means and the valve control means. Therefore, the behavior of the valve is not disturbed and the hitting performance is stabilized.

  According to the present invention, the impact performance can be stabilized.

1 is a schematic view of a first embodiment of a hydraulic striking device of a piston front / rear chamber high / low pressure switching type according to the present invention. It is explanatory drawing of the valve body in the hydraulic striking device concerning a first embodiment. It is an operation principle figure of the hydraulic striking device concerning a first embodiment. It is the 1st modification of 1st embodiment, and is a mimetic diagram of a hydraulic striking device which provided a high pressure passage inside a valve. It is a 2nd modification of 1st embodiment, and is a schematic diagram of the hydraulic striking device provided with the reverse action type valve | bulb. It is a schematic diagram of 2nd embodiment of the hydraulic striking device of the piston front-rear chamber high / low pressure switching type according to the present invention. It is a schematic diagram of one embodiment of a piston rear chamber high / low pressure switching hydraulic striking device according to the present invention. 1 is a schematic view of an embodiment of a hydraulic striking device of a rear chamber always high pressure-front chamber high / low pressure switching system according to the present invention. FIG. It is a schematic diagram of a conventional hydraulic striking device of the piston front and rear chamber high / low pressure switching type. It is an operation principle diagram of a conventional hydraulic striking device of a piston front / rear chamber high / low pressure switching type.

Hereinafter, embodiments or modifications of the present invention will be described with reference to the drawings as appropriate. In all the drawings, the same symbols are attached to the same components. In addition, apostrophes are added to the same reference numerals for components that have the same function but have been changed in layout and shape.
(First embodiment)
As shown in FIG. 1, the hydraulic striking device according to the first embodiment includes a cylinder 100 and a piston 200 slidably fitted in the cylinder 100 so as to be slidable along the axial direction. The piston 200 includes a large-diameter portion (front) 201 and a large-diameter portion (rear) 202 at the center in the axial direction, and small-diameter portions 203 and 204 formed before and after the large-diameter portions 201 and 202. An annular valve switching groove 205 is formed only at one location in the approximate center of the piston large diameter portions 201 and 202.

  Since the piston 200 is slidably fitted in the cylinder 100, the piston front chamber 110 and the piston rear chamber are separated from each other in the axial direction between the outer peripheral surface of the piston 200 and the inner peripheral surface of the cylinder 100. 111 are defined. In the cylinder 100, the piston front chamber 110 and the piston rear chamber 111 are alternately switched between the high pressure circuit 101 and the low pressure circuit 102, and the hydraulic oil is supplied and discharged so that the forward and backward movements of the piston 200 are repeated. A valve mechanism 210 is provided.

  The switching valve mechanism 210 has a valve chamber 130 formed non-coaxially with the piston 200 and a valve (spool) 300 slidably fitted in the valve chamber 130 inside the cylinder 100. In the valve chamber 130, a valve chamber small-diameter portion 132, a valve chamber large-diameter portion 131, and a valve chamber intermediate-diameter portion 133 are formed by multistage annular grooves in order from the front to the rear. The valve chamber large-diameter portion 131 is provided with a valve control chamber 137, a piston front chamber low pressure port 135, a piston high pressure port 134, and a piston rear chamber low pressure port 136, which are spaced apart from each other by a predetermined distance from the front to the rear. Yes.

  Connected to the piston front chamber 110 is a piston front chamber passage 120 that connects the piston front chamber 110 to the high pressure circuit 101 and the low pressure circuit 102 by switching the valve 300 forward and backward. On the other hand, a piston rear chamber passage 121 that connects the piston rear chamber 111 to the high pressure circuit 101 and the low pressure circuit 102 by switching the valve 300 forward and backward is connected to the piston rear chamber 111. The high voltage circuit 101 is provided with a high voltage accumulator 400, and the low voltage circuit 102 is provided with a low voltage accumulator 401.

  Between the piston front chamber 110 and the piston rear chamber 111, a piston reverse control port 113, a valve control port 114, and a piston forward control port 112 are provided at predetermined intervals from the front to the rear. The piston advance control port 112 has two openings for a normal stroke and a short stroke. The piston advance control port 112a on the piston front chamber 110 side is for a short stroke having a variable throttle. In this specification, the normal stroke setting, that is, the variable throttle is fully closed and the piston advance control port 112 on the piston rear chamber 111 side operates will be described.

  As shown in FIG. 2, the valve 300 is a hollow cylindrical valve body having a valve hollow passage 311 penetrating in the axial direction. The valve 300 includes valve large diameter portions 301, 302, and 303, a valve small diameter portion 304 provided on the front side of the valve large diameter portion 301, and a valve medium diameter portion 305 provided on the rear side of the valve large diameter portion 303. On the outer peripheral surface. An annular piston front chamber switching groove 306 is provided between the valve large diameter portion 301 and the valve large diameter portion 302, and between the valve large diameter portion 302 and the valve large diameter portion 303, the annular piston rear chamber switching groove 306 is provided. A chamber switching groove 307 is provided. That is, in the present embodiment, the piston front chamber switching groove 306 and the piston rear chamber switching groove 307 are “piston high / low pressure switching portions”.

The switching valve mechanism 210 is configured such that the valve large diameter portions 301, 302, and 303 are slidably fitted with the valve chamber large diameter portion 131, and the valve small diameter portion 304 is slidably fitted with the valve chamber small diameter portion 132. The valve middle diameter portion 305 is configured to be slidably fitted to the valve chamber middle diameter portion 133.
As for both end faces of the valve 300, the front is a valve front end face 308 and the rear is a valve rear end face 309. A valve stepped surface (front) 310 is formed at the boundary between the valve small diameter portion 304 and the valve large diameter portion 301, and a valve stepped surface (rear) is formed at the boundary between the valve large diameter portion 303 and the valve middle diameter portion 305. 312 is formed.

Here, assuming that the outer diameter of the valve large diameter portions 301, 302, 303 is φD1, the outer diameter of the valve small diameter portion 304 is φD2, the outer diameter of the valve middle diameter portion 305 is φD3, and the inner diameter of the valve hollow passage 311 is φD4. , ΦD1 to φD4 are as follows (Formula 1).
φD4 <φD2 <φD3 <φD1 (Formula 1)

Further, the pressure receiving area of the valve front end surface 308 is S1, the pressure receiving area of the valve rear end surface 309 is S2, the pressure receiving area S3 of the valve stepped surface (front), and the pressure receiving area of the valve stepped surface (rear) 312 is S4. The following (Formula 2).
S1 = π / 4 × (D2 ² −D4 ² )
S2 = π / 4 × (D3 ² −D4 ² )
S3 = π / 4 × (D1 ² −D2 ² )
S4 = π / 4 × (D1 ² −D3 ² ) (Formula 2)
And the relationship of pressure receiving area S1-S4 becomes as the following (Formula 3)-(Formula 5).

S1 <S2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (Formula 3)
[S1 + S3]> S2 (Equation 4)
S3> S4 (Equation 5)
The high pressure circuit 101 is connected to the piston high pressure port 134, and the low pressure circuit 102 is connected to the piston front chamber low pressure port 135 and the piston rear chamber low pressure port 136, respectively.

  One of the piston front chamber passages 120 is connected to the piston front chamber 110, and the other is connected to an intermediate portion between the piston high pressure port 134 and the piston front chamber low pressure port 135 of the valve chamber large diameter portion 131. One of the piston rear chamber passages 121 is connected to the piston rear chamber 111, and the other is connected to an intermediate portion between the piston high pressure port 134 and the piston rear chamber low pressure port 136 of the valve chamber large diameter portion 131.

The valve high pressure passage (front) 123 connects the piston reverse control port 113 and the front end surface of the valve chamber 130, and the valve high pressure passage (rear) 124 is connected to the rear end surface of the valve chamber 130 and the high pressure accumulator 400 of the high pressure circuit 101. Is also connected to a position on the upstream side (right side in FIG. 1). Therefore, the valve hollow passage 311 is always at a high pressure. The valve high pressure passage (front) 123 may connect the piston reverse control port 113 and the valve high pressure passage (rear) 124.
The valve low pressure passage 125 connects the piston advance control port 112 and the piston rear chamber low pressure port 136. The valve control passage 126 connects the valve control port 114 and the valve control chamber 137. The valve low pressure passage 125 may connect the piston advance control port 112 and the low pressure circuit 102.

  Here, in the hydraulic striking device of the present embodiment, the switching valve mechanism 210 includes passages constituting valve control means and valve urging means, that is, a valve high pressure passage (rear) 124, a hollow passage 311, a valve high pressure passage ( Front) 123, piston retraction control port 113, valve control port 114, valve control passage 126 (hereinafter referred to as "valve drive circuit"), and a passage through which pressure oil is supplied to the piston rear chamber 111, that is, piston high pressure A high pressure accumulator 400 is interposed between the port 134 and the piston rear chamber passage 121.

Next, the operation and effects of the hydraulic striking device of this embodiment will be described with reference to FIG. In FIG. 3, the passage in the high pressure state is indicated by “shaded”.
As shown in FIG. 3A, when the valve 300 of the switching valve mechanism 210 is switched to the forward position, the piston high pressure port 134 and the piston rear chamber passage 121 communicate with each other, and the piston rear chamber 111 becomes high pressure. On the other hand, the piston front chamber low pressure port 135 and the piston front chamber passage 120 communicate with each other, and the piston front chamber 110 becomes low pressure. Thereby, the piston 200 moves forward.

At this time, the valve chamber 130 is always connected to the high-pressure circuit 101 by a valve high-pressure passage (rear) 124, and both the valve front end surface 308 and the valve rear end surface 309 are at high pressure. Since high pressure is acting on both the valve front end surface 308 and the valve rear end surface 309, the valve 300 is held in the forward position by the above (Equation 3) (see FIG. 3A).
In this embodiment, the configuration in which the forward thrust is always applied to the valve 300 by the pressure receiving area difference between the valve front end surface 308 and the valve rear end surface 309 is described in “Valve Energizing Means” described in the means for solving the above problems. Is supported.

  Next, the piston 200 moves forward and communication between the valve control port 114 and the piston advance control port 112 is interrupted. Instead, the valve control port 114 communicates with the piston reverse control port 113. As a result, the high pressure oil from the valve high pressure passage (front) 123 is supplied to the valve control chamber 137 through the valve control passage 126. When the valve control chamber 137 becomes a high pressure, a high pressure acts on the stepped surface 310, and the valve 300 starts to retreat by the above (Equation 4) (see FIG. 3B).

In this embodiment, the configuration in which the pressure oil is supplied to the valve control chamber 137 and the valve 300 is moved backward against the forward thrust (= the biasing force of the valve biasing means) that always works is described above. Corresponds to "valve control means".
The piston 200 reaches the impact point when the impact efficiency is maximum (between FIGS. 3B to 3C), and at the impact point, the tip of the piston 200 moves the rear end of the impact rod (not shown). Blow. Thereby, the shock wave generated by the impact propagates to the bit at the tip through the rod and is used as energy for crushing the rock mass.

  Immediately after the piston 200 reaches the strike point, the valve 300 is completely switched to its retracted position. In the valve retracted position, the piston high pressure port 134 and the piston front chamber passage 120 communicate with each other, and the piston front chamber 110 becomes high pressure. On the other hand, the piston rear chamber low pressure port 136 and the piston rear chamber passage 121 communicate with each other, and the piston rear chamber 111 becomes low pressure. As a result, the piston 200 turns backward. While the valve control chamber 137 maintains a high pressure, the valve 300 is held in the retracted position (see FIG. 3C).

  Next, the piston 200 is retracted, communication between the valve control port 114 and the piston retract control port 113 is interrupted, and instead, the valve control port 114 communicates with the piston advance control port 112. As a result, the valve control chamber 137 is connected to the low pressure circuit 102 through the valve control passage 126 and the valve low pressure passage 125. When the valve control chamber 137 becomes a low pressure, the valve 300 starts moving forward according to the above (Equation 3) (see FIG. 3D). Then, the valve 300 is switched to the forward position again, and the hitting cycle is repeated.

  Here, in the hydraulic striking device of the present embodiment, when the piston 200 strikes the rod at the striking point (between (b) and (c) in FIG. 3), the piston 200 stops suddenly in the rear chamber 111. For this reason, an impact is generated in the pressure oil by a so-called water hammer action (water hammer). At this time, since the valve 300 does not reach the rear end stroke completely, the impact of the pressure oil is applied to all passages connected to the high pressure. Propagate. Since the “valve drive circuit” is connected to a high pressure, the behavior of the valve 300 may become unstable when the impact of the water hammer effect is transmitted.

  On the other hand, in the present embodiment, the valve high-pressure passage 124 connects the upstream side of the high-pressure accumulator 400 of the high-pressure circuit 101 and the valve chamber middle diameter portion 133 that is the valve rear chamber. That is, since the high-pressure accumulator 400 is interposed between the piston rear chamber 111 and the valve drive circuit, the impact in the pressure oil is transmitted to the valve front end surface 308 and the valve rear end surface 309 in the valve control chamber 137 and the valve chamber 130. Can be suppressed. Therefore, the forward biasing force of the valve 300 and the reverse thrust acting against the biasing force are stabilized. Therefore, since the behavior of the valve 300 is stabilized, the impact performance is stabilized.

In the present embodiment, the following items 1 to 4 are obtained by organizing the features of the configuration other than that the valve behavior is stable.
Item 1) The mechanism for driving the valve 300 is the valve urging means and the valve control means as described above, and the hydraulic circuit of the valve urging means has nothing to do with the operation of the piston 200. The hydraulic circuits constituting the valve control means are not connected between the piston front chamber 110 and the piston rear chamber 111, and the piston front chamber 110 and the piston rear chamber 111 do not communicate with each other. (Always isolated so as not to be pulled in).

Item 2) The mechanism for driving the valve 300 is a valve urging means and a valve control means, and the valve urging means always urges the valve 300 in one direction to supply pressure oil to the valve control chamber 137. The forward / backward movement of the valve 300 is switched by supply / discharge.
Item 3) Only one port of the valve control port 114 is connected to the valve control chamber 137.
Item 4) The valve 300 has a hollow structure having a valve hollow passage 311 penetrating in the axial direction.

The structure of the above items 1 to 4 of the present embodiment is compared with the conventional piston front / rear chamber high / low pressure switching hydraulic striking device described with reference to FIGS.
Item 1) In the above-described prior art, the relationship between the piston front and rear chambers and the respective circuits related to the valve drive is in a mutually communicating relationship. For this reason, the degree of freedom in layout of the circuit configuration is low. On the other hand, in the structure of the present embodiment, the hydraulic circuit of the valve urging means has nothing to do with the operation of the piston 200 and is isolated from the piston front and rear chambers so as not to draw hydraulic oil. Therefore, the relationship between the piston front and rear chambers and the circuits related to the valve drive is independent. Therefore, it can be said that the structure of this embodiment has a high degree of freedom in the layout of the circuit configuration compared to the above-described conventional technology.

  In particular, since the above-described prior art has a low degree of freedom in the layout of the circuit configuration, it is necessary to provide both the supply and discharge passages for the pressure oil on the forward side and the backward side for driving the valve. Therefore, five passages for driving the valve are required between the front chamber and the rear chamber of the piston, as shown in FIG. On the other hand, in the present embodiment, as shown in FIG. 1, there are only three locations, that is, the piston backward control port 113, the valve control port 114, and the piston forward control port 112.

  A small number of passages directly leads to a reduction in processing costs. In addition, the high degree of freedom in the layout of the circuit configuration enables the passage length to be shortened by arranging piston rear chambers, valves, and accumulators together. Thereby, it is possible to improve hydraulic efficiency, and it is also possible to expand the passage area of the piston rear chamber passage 121 connected to the piston rear chamber 111 to cope with a large amount of oil.

  Furthermore, the hydraulic circuit of the above prior art has not only a large number of passages, but also connects the front chamber of the piston and the rear chamber of the valve, and the rear chamber of the piston and the front chamber of the valve as shown in FIG. Therefore, it can be seen that the hydraulic circuits are arranged so as to cross each other and have a very complicated layout. On the other hand, the structure of the present embodiment is a very simple circuit as shown in FIG. Therefore, the processing cost can be reduced.

Regarding Item 2) The above prior art employs a valve front / rear chamber high / low pressure switching type and includes a holding mechanism for holding the valve at a timing when both the front and rear chambers of the valve are at a low pressure. As shown in FIG. 5, the outer diameter shape that is in sliding contact with the valve chamber needs a multistage structure of five stages, that is, small diameter-medium diameter-large diameter-medium diameter-small diameter from the front to the rear. Further, it is necessary to provide pressure oil supply / exhaust passages for holding the valve at two locations in the front and rear. On the other hand, the valve structure of the present embodiment has only three stages of a small diameter, a large diameter, and a medium diameter, and the valve structure itself is not necessary because the valve does not require processing of a supply / discharge oil passage for its own holding mechanism. Can be made extremely simple. The simplicity of the valve structure of the present embodiment can not only reduce the processing cost of the valve itself, but naturally increases the processing cost of the corresponding valve chamber side, that is, the cylinder inner diameter processing. Can be reduced.

Item 3) In the above prior art, in the valve front chamber, the ports connected via the valve control passage (front) are the two positions of the piston forward control port and the piston backward control interlocking port. In FIG. 10 (b), the piston retraction control interlocking port is opposed to discharging the pressure oil in the valve front chamber in the valve advancement phase, which is its original function, to the oil discharge port. The pressure oil in the port leaks to the oil discharge port (this phenomenon is the same for the piston reverse control interlocking port in the valve reverse phase). Generally, in the striking device, the greater the number of ports, the greater the number of places where pressure oil leaks.

On the other hand, in the structure of the present embodiment, focusing on the valve control chamber 137, since the port connected through the valve control passage 126 is only one place of the valve control port 114, the amount of leakage is kept to a minimum. be able to.
Further, in this embodiment, the period from FIG. 3C to FIG. 3D, that is, until the valve control port 114 communicates with the piston forward control port 112 after the communication state with the piston reverse control port 113 is interrupted. The valve control chamber 137 is closed by the piston large diameter part (rear) 202, and the pressure oil is sealed in the closed circuit to hold the valve 300 in the retracted position. If the amount of leak is large in a state where the valve is not supplied, the behavior of the valve 300 becomes unstable. Therefore, it can be said that one port is preferably connected to the valve control port 114. As described above, in this embodiment, the valve control port 114 is set to stabilize the behavior of the valve 300 as well as reducing the amount of pressure oil leakage to increase the impact efficiency.

Item 4) In the above prior art, the valve has a solid structure because the oil supply / discharge oil passage constituting the valve holding mechanism is provided inside the valve. On the other hand, in this embodiment, since the valve 300 has a hollow structure having a valve hollow passage 311 penetrating in the axial direction, weight reduction is achieved by hollowing out the valve. Therefore, the amount of oil consumed for driving the valve can be reduced, and the impact efficiency is improved.

As described above, the hydraulic striking device of the piston front / rear chamber high / low pressure switching type according to the present embodiment has a high striking force by switching the piston front / rear chamber high / low pressure, but has a reduced processing cost and hydraulic efficiency. Can be improved.
Also, in general, at the stroke end before and after the valve of the hydraulic striking device, the pressure may be reduced to below atmospheric pressure due to the negative pressure acting on the low pressure circuit, in which case cavitation occurs May be a problem. In contrast, in this embodiment, the valve hollow passage 311, the valve front end surface 308, and the valve rear end surface 309 are constantly at high pressure, so that cavitation is generated compared to the case where some of these portions are switched to low pressure. Can be suppressed.

  Further, in the present embodiment, in the middle of switching from (d) to (a) in FIG. 3, that is, the valve 300 is switched to the front end position, the piston front chamber 110 becomes low pressure, the piston rear chamber 111 becomes high pressure, and the piston 200. Since the piston front chamber 110 and the valve control port 114 both have low pressure during the retreat to the rear stroke end while decelerating, the piston large-diameter portion (front) 201 is prone to oil film breakage and cavitation also occurs. It is exposed to an easy condition. On the other hand, in this embodiment, since the piston retraction control port 113 is always at a high pressure and a small amount of pressure oil leaks therefrom, it is possible to suppress the occurrence of oil film breakage and cavitation.

  As described above, the piston front / rear chamber high / low pressure switching type hydraulic striking device of the present embodiment is provided with a high striking force by switching the piston front / rear chamber high / low pressure, thereby improving the striking efficiency and the valve control means. Since the accumulator is provided between the path for supplying the pressure oil to the path and the path for supplying the pressure oil to the piston rear chamber, the impact performance can be stabilized.

Hereinafter, modifications of this embodiment and other embodiments will be further described.
FIG. 4 shows a first modification of the first embodiment. As shown in the figure, in this first modification, a valve main body high-pressure passage 313 penetrating in the radial direction is provided in the valve large-diameter portion 302 of the valve 300a instead of the valve high-pressure passage 124 shown in FIG. This is an example. In this example, one end of the valve high-pressure passage 123 ′ is connected to the upstream side of the high-pressure accumulator 400 of the high-pressure circuit 101.

According to the first modification, the valve high-pressure passage (rear) 124 in FIG. 1 can be omitted. Therefore, the configuration of the hydraulic circuit can be further simplified, so that the processing cost is reduced. Since the valve main body high-pressure passage 313 is a through hole that penetrates in the radial direction and does not have a bent portion in the middle like the communication passage of the conventional valve holding mechanism, the processing of the valve main body high-pressure passage 313 is very easy. .
However, in the first modified example, unlike the first embodiment, there is a high pressure between the valve urging means (hollow passage 311, valve front end surface 308, valve rear end surface 309) and the piston rear chamber 111. Accumulator 400 is not interposed. Therefore, compared with the said 1st embodiment shown in FIG. 1, the behavior at the time of the water hammer effect | action of the valve 300a falls stability.
(Second modification)
FIG. 5 shows a second modification of the first embodiment. This second modification is an example in which the groove structure of the valve body and the circuit configuration of the valve control means are changed. As shown in the figure, the second modification is a case where the operation relationship of the piston-valve is opposite to that of the first embodiment shown in FIG.
Specifically, as shown in FIG. 5, the valve 300b is a hollow cylindrical valve body provided with a valve hollow passage 311 ′ penetrating in the axial direction. The valve 300b is provided on the rear side of the valve large diameter portion 301 ′, 302 ′, 303 ′, the valve small diameter portion 304 ′ provided on the front side of the valve large diameter portion 301 ′, and the valve large diameter portion 303 ′. And a valve middle diameter portion 305 ′. A piston front chamber oil drain groove 314 is provided between the valve large diameter portion 301 ′ and the valve large diameter portion 302 ′. A piston rear chamber oil drain groove 315 is provided between the valve large diameter portion 303 ′ and the valve middle diameter portion 305 ′. Further, a piston front / rear chamber switching groove 316 is provided between the valve large diameter portion 302 ′ and the valve large diameter portion 303.

As for both end surfaces of the valve 300b, the front is a valve front end surface 308 ′ and the rear is a valve rear end surface 309 ′. A valve stepped surface (front) 310 ′ is formed at the boundary between the valve small diameter portion 304 ′ and the valve large diameter portion 301 ′.
The valve high pressure passage (front) 123 ″ connects the piston advance control port 112 and the valve high pressure passage (rear) 124. The valve low-pressure passage 125 ′ connects the piston retraction control port 113 and the piston front chamber low-pressure port 135. The valve control passage 126 connects the valve control port 114 and the valve control chamber 137 as in the first embodiment shown in FIG. Thereby, according to this 2nd modification, the operation | movement relationship of a piston valve is reverse with 1st embodiment shown in FIG. 1 (reverse action valve).

  The greatest feature of the second modification is that the piston advance control port 112 is always connected to the high-pressure circuit. In other words, as described above, in the hydraulic circuit of the striking device, cavitation is likely to occur at a location where low pressure is connected. In the striking device of the first embodiment, the short stroke port 112a of the piston advance control port 112 corresponds to this.

  Therefore, in the example shown in FIG. 1 and FIG. 4, since the short stroke port 112a is always connected to a low pressure, erosion is likely to occur at the relevant location, so this second modification can be adopted. It may be preferable. In particular, when the variable throttle is fully closed (that is, used at a work site that operates only with a long stroke), it is effective to adopt this second modification in order to prevent the occurrence of erosion at that location. is there. However, since the piston retraction control port 113 is always at a low pressure, the oil film breakage preventing effect and the cavitation suppressing effect of the piston large diameter portion (front) 201 described above are reduced.

(Second embodiment)
Next, a second embodiment of the hydraulic striking device of the piston front / rear chamber high / low pressure switching type according to the present invention will be described. FIG. 6 is a schematic diagram of the second embodiment. In the first embodiment and the modifications thereof, an example in which a hollow valve is employed has been shown. However, the present embodiment is an example in which a solid valve is employed. Only differences from the first embodiment will be described below.

  As shown in FIG. 6, a valve chamber 150 is formed in the cylinder 100 a non-coaxially with the piston 200, and a valve 350 is slidably fitted in the valve chamber 150. The valve chamber 150 includes a valve front chamber 152, a valve main chamber 151, and a valve rear chamber 153 in order from the front to the rear. In the valve main chamber 151, a piston front chamber low pressure port 155, a piston high pressure port 154, and a piston rear chamber low pressure port 156 are provided in order from the front to the rear in order from each other with a predetermined interval.

  The valve 350 is a solid valve body, and includes a valve large diameter portion 351, 352, 353, a valve medium diameter portion 354 provided on the front side, and a valve small diameter portion 355 provided on the rear side. Have on the surface. An annular piston front chamber switching groove 356 is provided between the valve large diameter portion 351 and the valve large diameter portion 352. An annular piston rear chamber switching groove 357 is provided between the valve large diameter portion 352 and the valve large diameter portion 353. In the present embodiment, the piston front chamber switching groove 356 and the piston rear chamber switching groove 357 constitute a “piston high / low pressure switching portion”.

  The valve large diameter portions 351, 352, and 353 are slidably fitted to the valve main chamber 151, the valve middle diameter portion 354 is slidably fitted to the valve front chamber 152, and the valve small diameter portion 355 is slidably fitted to the valve rear chamber 153. Has been. As for both end surfaces of the valve 350, the front is a valve front end surface 358 and the rear is a valve rear end surface 359. Here, the outer diameter of the valve medium diameter portion 354 is set larger than the outer diameter of the valve small diameter portion 355. Therefore, the pressure receiving area of the valve front end surface 358 is larger than the pressure receiving area of the valve rear end surface 359.

  The high pressure circuit 101 is connected to the piston high pressure port 154, and the low pressure circuit 102 is connected to the piston front chamber low pressure port 155 and the piston rear chamber low pressure port 156. One of the piston front chamber passages 120 is connected to the piston front chamber 110, and the other is connected to an intermediate portion between the piston high pressure port 154 and the piston front chamber low pressure port 155 of the valve main chamber 151. One end of the piston rear chamber passage 121 is connected to the piston rear chamber 111, and the other end is connected to an intermediate portion between the piston high pressure port 154 and the piston rear chamber low pressure port 156 of the valve main chamber 151.

  The valve high pressure passage (front) 123 connects the piston reverse control port 113 and the valve high pressure passage (rear) 124. The valve high pressure passage 124 connects the valve rear chamber 153 and the upstream side (right side in FIG. 6) of the high pressure accumulator 400 of the high pressure circuit 101. Therefore, the valve rear chamber 153 is always at a high pressure, and forward thrust is always applied to the valve 350 by supplying pressure oil to the pressure receiving area of the valve rear end surface 359. In other words, in the second embodiment, the configuration in which the forward thrust is always applied to the valve 350 by supplying the pressure oil to the pressure receiving area of the valve rear end surface 359 with the valve rear chamber 153 always at a high pressure solves the above problem. This corresponds to the “valve urging means” described in the means for doing this.

  The valve low pressure passage 125 connects the piston advance control port 112 and the piston rear chamber low pressure port 156. The valve control passage 126 connects the valve control port 114 and the valve front chamber 152. The valve low pressure passage 125 may connect the piston advance control port 112 and the low pressure circuit 102.

  The valve control port 114 communicates with the piston retraction control port 113, and high-pressure oil from the valve high-pressure passage (front) 123 is supplied to the valve front chamber 152 through the valve control passage 126. As a result, the valve 350 moves backward due to the pressure receiving area difference between the valve front end surface 358 and the valve rear end surface 359. Here, in this second embodiment, the configuration in which the valve 350 is moved backward against the forward thrust against the valve 350 (= the urging force of the “valve urging means” that always works) described above solves the above problem. This corresponds to the “valve control means” described in the means. That is, the valve front chamber 152 of the present embodiment corresponds to the valve control chamber 137 of the first embodiment.

  The second embodiment is characterized in that the valve has a solid structure. Since the solid valve has higher rigidity than the hollow valve, it is possible to set a large difference in diameter between the large diameter portions 351, 352, and 353, the piston front chamber switching groove 356, and the piston rear chamber switching groove 357. The passage area of this part can be enlarged. Therefore, the configuration of the second embodiment is effective when a striking device with a high striking force specification with an ultra-high pressure and a large amount of oil is required even if the hydraulic efficiency is somewhat inferior. It should be noted that cavitation may occur at the valve switching stroke end (the front end surface of the large diameter portion 351 and the rear end surface of the large diameter portion 353), but other than that, basically the first shown in FIG. The same effects as the embodiment are achieved.

  As described above, in the above-described embodiment or modification of the present invention, the piston is driven by the front / rear chamber high / low pressure switching type, so that a high number of hits can be realized. And by placing a high-pressure accumulator between the piston rear chamber where the impact is generated in the hydraulic oil due to the water hammer and the hydraulic path for driving the valve, the impact of the hydraulic oil is unstable behavior of the valve. Can be prevented. Therefore, there is an effect that cannot be obtained from the circuit configuration relating to the piston front and rear chambers and the switching valve mechanism disclosed in the conventional hydraulic striking device.

As mentioned above, although embodiment thru | or modification of this invention were demonstrated with reference to drawings, the hydraulic striking device which concerns on this invention is not limited to the said embodiment thru | or modification, and deviates from the main point of this invention. If not, it is a matter of course that other various modifications and changes of each component are allowed.
For example, the valve urging means shown in FIG. 6 shows a configuration example in which the forward thrust is always applied to the valve 350 by constantly setting the valve rear chamber 153 to a high pressure and supplying pressure oil to the pressure receiving surface of the valve rear end surface 359. However, the present invention is not limited to this. For example, instead of the valve urging means that operates with hydraulic pressure, it is also possible to enclose a pressing force by a spring or a high-pressure gas and always apply a forward thrust to the valve 350 by the pressure. It is.

(One Embodiment of Piston Rear Chamber High / Low Pressure Switching Type Hydraulic Blowing Device According to the Present Invention)
By the way, as described above, the present invention is particularly suitable for stabilizing the striking performance of the hydraulic striking device of the front / rear chamber high / low pressure switching type for realizing a high striking number. The piston front chamber is always connected to high pressure and the piston rear chamber is alternately switched between high pressure and low pressure. I found out that the effect of.

Hereinafter, an embodiment in which the present invention is applied to a “piston rear chamber high / low pressure switching type” hydraulic striking device will be described with reference to FIG. 7 as appropriate. In addition, the piston and valve in the same figure show the state of the phase where the piston turns from the forward movement to the backward movement, and the lower side of the axis shows the state of the situation where the piston turns from the backward movement to the forward movement.
As shown in FIG. 7, the piston rear chamber high / low pressure switching hydraulic striking device includes a cylinder 100 b and a piston 200. The piston 200 has large-diameter portions 201 and 202 in the approximate center thereof, and small-diameter portions 203 and 204 are provided in front of and behind the large-diameter portions 201 and 202, respectively. An annular switching groove 205 is formed substantially at the center of the large diameter portions 201 and 202.

  The piston 200 is slid into the cylinder 100b, whereby a piston front chamber 110 and a piston rear chamber 111 are defined in the cylinder 100b. The piston front chamber 110 is always connected to the high-pressure circuit 101 via the piston front chamber passage 120. On the other hand, the piston rear chamber 111 can be alternately communicated with the high-pressure circuit 101 and the low-pressure circuit 102 by forward / reverse switching of a switching valve mechanism 210 described later. The high voltage circuit 101 is provided with a high voltage accumulator 400, and the low voltage circuit 102 is provided with a low voltage accumulator 401.

  The switching valve mechanism 210 has a valve chamber 150 formed non-coaxially with the piston 200 in the cylinder 100b, and has a valve 350 slidably fitted in the valve chamber 150. The valve chamber 150 includes a valve front chamber 152, a valve main chamber 151, and a valve rear chamber 153 in order from the front to the rear. In the valve main chamber 151, a piston rear chamber high-pressure port 154, a piston rear chamber switching port 158, and a piston rear chamber low-pressure port 156 are provided in order from the front to the rear, respectively, with a predetermined interval.

  The valve 350 is a solid cylindrical body, and has valve large diameter portions 351 and 352, a valve medium diameter portion 354 provided on the front side thereof, and a valve small diameter portion 355 provided on the rear side. . Between the valve small-diameter portion 355 and the valve large-diameter portion 352, a valve retraction restricting portion 355a that restricts the backward movement of the valve 350 is provided. An annular piston rear chamber high pressure switching groove 357 is provided between the valve large diameter portion 351 and the valve large diameter portion 352, and between the valve large diameter portion 352 and the valve retraction regulating portion 355a, A room low-pressure switching groove 357a is provided.

  The valve large diameter portions 351 and 352 are slidably fitted to the valve main chamber 151, the valve middle diameter portion 354 is slidably fitted to the valve front chamber 152, and the valve small diameter portion 355 is slidably fitted to the valve rear chamber 153. Yes. Here, the outer diameter of the valve middle diameter portion 354 is set larger than the outer diameter of the valve small diameter portion 355. Accordingly, the pressure receiving area on the valve middle diameter portion 354 side is larger than the pressure receiving area on the valve small diameter portion 355 side. Between the piston front chamber 110 and the piston rear chamber 111, a piston forward control port 112, a piston reverse control port 113, and an oil discharge port 115 are provided at predetermined intervals from the front to the rear. .

  The downstream side (left side in the figure) of the high pressure accumulator 400 of the high pressure circuit 101 is connected to the piston rear chamber high pressure port 154 via the piston rear chamber high pressure passage 121a. The upstream side (the right side in the figure) of the high pressure accumulator 400 of the high pressure circuit 101 is connected to the piston front chamber 110 via the piston front chamber passage 120 and has a valve high pressure passage 124 branched from the piston front chamber passage 120. And is connected to the valve rear chamber 153.

  One end of a valve control passage 126 is connected to the valve front chamber 152, and the other end of the valve control passage 126 is branched into a front passage 126a and a rear passage 126b. The front passage 126 a is connected to the piston advance control port 112, and the rear passage 126 b is connected to the piston reverse control port 113. The piston rear chamber 111 is connected to the piston rear chamber switching port 158 by the piston rear chamber passage 121. The oil discharge port 115 is connected to the low pressure circuit 102 via a valve low pressure passage 125. The piston rear chamber low pressure switching port 156 is connected to the low pressure circuit 102 via the piston rear chamber low pressure passage 121b.

  Here, the valve 350 is always urged forward because the valve rear chamber 153 is always at a high pressure, but this configuration corresponds to the “valve urging means” described in the means for solving the above problems. doing. When the high pressure oil is supplied to the valve front chamber 152 through the valve control passage 126a, the valve 350 moves backward due to the pressure receiving area difference between the valve front chamber 152 and the valve rear chamber 153, and the pressure oil is discharged through the valve control passage 126b. Then, the valve moves forward again, but the configuration in which the pressure oil is supplied to the valve front chamber 152 and the valve 350 moves backward corresponds to the “valve control means”.

  As described above, in this embodiment, the piston front chamber 110 is always connected to the high pressure, and the piston rear chamber 111 is alternately connected to the high pressure and the low pressure by the back and forth movement of the valve 350 so that the piston 200 moves back and forth. The piston rear chamber high / low pressure switching type hydraulic striking device (for example, see FIG. 1 of Japanese Patent No. 4912785) has a basic configuration.

  However, this embodiment is different from the conventional hydraulic striking device in that a path for supplying pressure oil to the piston rear chamber 111 (piston rear chamber high pressure passage 121a, piston rear chamber high pressure port 154, piston rear chamber high pressure switching groove 357, And piston rear chamber passage 121) and valve urging means (valve high pressure passage 124 and valve rear chamber 153) and valve control means (piston front chamber passage 120, piston front chamber 110, valve control passage 126, and valve front chamber 152). This is different in that a high-pressure accumulator 400 is provided between the pressure oil and the path for supplying pressure oil to the pipe.

  Accordingly, even in the piston rear chamber high / low pressure switching type hydraulic striking device, the piston rear chamber 111 in which impact is generated in the pressure oil by the water hammer action and the valve drive, as in the first and second embodiments. By disposing the high-pressure accumulator 400 between the hydraulic path and the oil pressure path, it is possible to prevent the impact of the pressure oil from affecting the unstable behavior of the valve 350.

(Embodiment of a hydraulic striking device of the rear chamber always high pressure-front chamber high / low pressure switching system according to the present invention)
Further, the present inventor has disclosed a so-called “rear chamber constant high pressure-front chamber high / low pressure switching system” hydraulic striking device in which the piston rear chamber is always connected to high pressure and the piston front chamber is alternately switched between high pressure and low pressure. Also found that the same effect was achieved in stabilizing the valve behavior. Hereinafter, an embodiment in which the present invention is applied to a hydraulic striking device of “rear chamber constant high pressure-front chamber high / low pressure switching system” will be described with reference to FIG. 8 as appropriate. FIG. 8 is a schematic view of an embodiment of a hydraulic striking device of the rear chamber always high pressure-front chamber high / low pressure switching system according to the present invention.

  As shown in FIG. 8, the hydraulic striking device includes a cylinder 100 and a piston 200 slidably fitted in the cylinder 100 so as to be slidable along the axial direction. The piston 200 includes a large-diameter portion (front) 201, a large-diameter portion (rear) 202 at the center in the axial direction, a small-diameter portion (front) 203 formed before and after the large-diameter portions 201, 202, and a small-diameter portion (rear). 204. The diameter of the small diameter part (front) 203 is set smaller than the diameter of the small diameter part (rear) 204. An annular valve switching groove 205 is formed in the approximate center of the piston large diameter portions 201 and 202.

  Since the piston 200 is slidably fitted in the cylinder 100, the piston front chamber 110 and the piston rear chamber are separated from each other in the axial direction between the outer peripheral surface of the piston 200 and the inner peripheral surface of the cylinder 100. 111 are defined. A switching valve mechanism 210 is provided inside the cylinder 100 to supply and discharge hydraulic fluid so that the piston front chamber 110 is alternately switched between the high pressure circuit 101 and the low pressure circuit 102 so that the forward and backward movement of the piston 200 is repeated. It has been.

  The switching valve mechanism 210 has a valve chamber 130 formed non-coaxially with the piston 200 and a valve (spool) 300 slidably fitted in the valve chamber 130 inside the cylinder 100. In the valve chamber 130, a valve chamber small-diameter portion 132, a valve chamber large-diameter portion 131, and a valve chamber intermediate-diameter portion 133 are formed by multistage annular grooves in order from the front to the rear. The valve chamber large-diameter portion 131 is provided with a valve control chamber 137, a piston front chamber low pressure port 135, a piston front chamber high pressure port 134, and a low pressure port 136, which are spaced apart from each other by a predetermined distance from the front to the rear. .

  Connected to the piston front chamber 110 is a piston front chamber passage 120 that connects the piston front chamber 110 to the high pressure circuit 101 and the low pressure circuit 102 by switching the valve 300 forward and backward. On the other hand, the piston rear chamber 111 is connected to a piston rear chamber passage 121 that is always in communication with the high-pressure circuit 101. The high voltage circuit 101 is provided with a high voltage accumulator 400, and the low voltage circuit 102 is provided with a low voltage accumulator 401.

  Between the piston front chamber 110 and the piston rear chamber 111, a piston reverse control port 113, a valve control port 114, and a piston forward control port 112 are provided at predetermined intervals from the front to the rear. The piston advance control port 112 has two openings for a normal stroke and a short stroke. The piston advance control port 112a on the piston front chamber 110 side is for a short stroke having a variable throttle. In this specification, the normal stroke setting, that is, the variable throttle is fully closed and the piston advance control port 112 on the piston rear chamber 111 side operates will be described.

  The valve 300 is a hollow cylindrical valve body having a valve hollow passage 311 penetrating in the axial direction. The valve 300 has an outer periphery of valve large-diameter portions 301 and 302, a valve small-diameter portion 304 provided on the front side of the valve large-diameter portion 301, and a valve medium-diameter portion 305 provided on the rear side of the valve large-diameter portion 302. Have on the surface. An annular piston front chamber switching groove 306 is provided between the valve large diameter portion 301 and the valve large diameter portion 302.

  The switching valve mechanism 210 is configured such that the valve large diameter portions 301 and 302 are slidably fitted with the valve chamber large diameter portion 131, and the valve small diameter portion 304 is slidably fitted with the valve chamber small diameter portion 132. The middle diameter portion 305 is configured to be slidably fitted to the valve chamber middle diameter portion 133. As for both end faces of the valve 300, the front is a valve front end face 308 and the rear is a valve rear end face 309. A valve stepped surface (front) 310 is formed at the boundary between the valve small diameter portion 304 and the valve large diameter portion 301, and a valve stepped surface (rear) is formed at the boundary between the valve large diameter portion 302 and the valve middle diameter portion 305. 312 is formed.

  The high pressure circuit 101 is connected to the piston front chamber high pressure port 134, and the low pressure circuit 102 is connected to the piston front chamber low pressure port 135 and the low pressure port 136, respectively. One of the piston front chamber passages 120 is connected to the piston front chamber 110, and the other is connected to an intermediate portion between the piston front chamber high pressure port 134 and the piston front chamber low pressure port 135 of the valve chamber large diameter portion 131.

  The valve high pressure passage (front) 123 connects the piston reverse control port 113 and the front end surface of the valve chamber 130, and the valve high pressure passage (rear) 124 is connected to the rear end surface of the valve chamber 130 and the high pressure accumulator 400 of the high pressure circuit 101. Is also connected to the upstream position (right side in the figure). Therefore, the valve hollow passage 311 is always at a high pressure. The valve high pressure passage (front) 123 may connect the piston reverse control port 113 and the valve high pressure passage (rear) 124.

The valve low pressure passage 125 connects the piston advance control port 112 and the low pressure port 136. The valve control passage 126 connects the valve control port 114 and the valve control chamber 137. The valve low pressure passage 125 may directly connect the piston advance control port 112 and the low pressure circuit 102.
Since the hollow passage 311 is always connected to a high pressure, the valve 300 is always attached to the front due to a difference in outer diameter size, that is, a pressure receiving area difference between the valve front end surface 308 and the valve rear end surface 309 on which high pressure oil acts. This configuration corresponds to the “valve urging means” described in the means for solving the above problems.

  Further, when the piston retraction control port 113 and the valve control port 114 communicate with each other through the valve switching groove 205 and the high pressure oil in the valve high pressure passage (front) 123 is supplied to the valve control chamber 137 via the valve control passage 126, the valve 300 Although the valve 300 moves backward against the forward biasing force acting on the above, these configurations correspond to the “valve control means” described in the means for solving the above problems.

  Here, in this hydraulic striking device, the switching valve mechanism 210 includes passages constituting “valve control means” and “valve urging means”, that is, a valve high-pressure passage (rear) 124, a hollow passage 311, and a valve high-pressure passage. Pressure oil is supplied to (front) 123, piston retraction control port 113, valve control port 114, valve control passage 126 (hereinafter collectively referred to as “valve drive circuit”), and piston rear chamber 111. A high pressure accumulator 400 is interposed between the passage, that is, the piston high pressure port 134 and the piston rear chamber passage 121.

  According to this hydraulic striking device, the operation of the switching valve mechanism 210 causes the piston front chamber 110 to be alternately switched between high pressure and low pressure, and when the piston front chamber 110 is connected to low pressure, the piston rear chamber 111 is always at high pressure. Since it is connected, the piston 200 moves forward. When the piston front chamber 110 is connected to a high pressure, the piston 200 moves backward due to the difference in pressure receiving area with the piston rear chamber 111.

  Here, in this hydraulic striking device, when the piston 200 strikes the rod at the striking point, the piston 200 stops suddenly, and therefore, in the piston rear chamber 111, an impact is generated on the pressure oil by a so-called water hammer action (water hammer). To do. At this time, the valve 300 has not completely reached the rear end stroke. Therefore, the impact of pressure oil propagates to all the passages connected to the high pressure. In particular, since the “valve drive circuit” is connected to a high pressure, the behavior of the valve 300 may become unstable when the impact of this water hammer effect is transmitted.

  On the other hand, in this hydraulic striking device, the valve high-pressure passage 124 connects the valve chamber middle diameter portion 133 serving as the valve rear chamber and the upstream side of the high-pressure accumulator 400 of the high-pressure circuit 101. That is, since the high-pressure accumulator 400 is interposed between the piston rear chamber 111 and the “valve drive circuit”, the impact in the pressure oil is applied to the valve front end surface 308 and the valve rear end surface 309 in the valve control chamber 137 and the valve chamber 130. It is possible to suppress transmission. Therefore, the forward biasing force of the valve 300 and the reverse thrust acting against the biasing force are stabilized. Therefore, since the behavior of the valve 300 is stabilized, the impact performance is stabilized.

100 cylinder 100a cylinder 101, 101 ′ high pressure circuit 102, 102 ′ low pressure circuit 110 piston front chamber 111 piston rear chamber 112 piston advance control port 112a〃 (short stroke)
113 Piston retraction control port 114 Valve control port 120 Piston front chamber passage 121 Piston rear chamber passage 123, 123 ', 123 "Valve high pressure passage (front)
124 Valve high pressure passage (rear)
125 Valve low pressure passage 126 Valve control passage 127 Valve high pressure passage 128 Valve low pressure passage (front)
129 Valve low pressure passage (rear)
130 Valve chamber 131 Valve chamber large diameter portion 132 Valve chamber small diameter portion 133 Valve chamber medium diameter portion 134 Piston high pressure port 135 Piston front chamber low pressure port 136 Piston rear chamber low pressure port 137 Valve control chamber 138 Piston front chamber high pressure port 139 Piston rear chamber High pressure port 140 Piston low pressure port 150 Valve chamber 151 Valve main chamber 152 Valve front chamber 153 Valve rear chamber 154 Piston high pressure port 155 Piston front chamber low pressure port 156 Piston rear chamber low pressure port 157 Valve biasing chamber 200 Piston 201 Large diameter portion (front )
202 Large diameter part (rear)
203 Small diameter part (front)
204 Small diameter part (rear)
205 Valve switching groove 210 Switching valve mechanism 300 Valve (hollow)
300a valve (hollow, built-in passage)
300b Valve (hollow, reverse operation)
301, 301 'Valve large diameter part (front)
302, 302 'Valve large diameter part (middle)
303, 303 'Valve large diameter part (rear)
304, 304 ′ Valve small diameter portion 305, 306 ′ Valve medium diameter portion 306 Piston front chamber switching groove (piston high / low pressure switching portion)
307 Piston rear chamber switching groove (piston high / low pressure switching section)
308, 308 'Valve front end surface 309, 309' Valve rear end surface 310, 310 'Valve stepped surface (front)
311, 311 ′ Valve hollow passage 312 Valve stepped surface (rear)
313 Valve body high-pressure passage 314 Piston front chamber oil drain groove 315 Piston rear chamber oil drain groove 316 Piston front / rear chamber switching groove 350 Valve (solid)
351 Valve large diameter part (front)
352 Valve Large Diameter (Medium)
353 Valve large diameter part (rear)
354 Valve middle diameter portion 355 Valve small diameter portion 356 Piston front chamber switching groove 357 Piston rear chamber switching groove 358 Valve front end surface 359 Valve rear end surface 400 High pressure accumulator 401 Low pressure accumulator

Claims (4)

A cylinder, a piston slidably fitted in the cylinder, a piston front chamber and a piston rear defined between an outer peripheral surface of the piston and an inner peripheral surface of the cylinder and spaced apart in the axial direction And a switching valve mechanism that alternately switches the piston front chamber and the piston rear chamber to a high pressure circuit and a low pressure circuit, and hydraulically presses the striking rod by moving the piston back and forth in the cylinder. A striking device,
The piston has a large-diameter portion, small-diameter portions provided respectively before and after the large-diameter portion, and a valve switching groove formed in the approximate center of the large-diameter portion in the axial direction. Has multiple control ports,
The switching valve mechanism includes a valve chamber formed non-coaxially with the piston in the cylinder and connected to the plurality of control ports, a valve slidably fitted in the valve chamber, and a forward and backward movement of the valve. A valve urging means for constantly urging in one direction, and a valve control means for moving the valve in the opposite direction against the urging force of the valve urging means when pressurized oil is supplied. And an accumulator provided between a path for supplying pressure oil to the valve control means and a path for supplying pressure oil to the piston rear chamber,
The switching valve mechanism supplies and discharges pressure oil to and from the valve control means by allowing the plurality of control ports to communicate with each other in accordance with the back-and-forth movement of the valve switching groove caused by the forward and backward movement of the piston. The piston front chamber and the piston rear chamber are alternately switched between a high pressure circuit and a low pressure circuit in accordance with the forward / backward movement of the valve, and hydraulic oil is supplied and discharged so that the forward and backward movement of the piston is repeated. A hydraulic striking device characterized in that   2. The hydraulic striking device according to claim 1, wherein an accumulator is provided between a path for supplying pressure oil to the valve biasing means and a path for supplying pressure oil to the piston rear chamber. . A cylinder, a piston slidably fitted in the cylinder, a piston front chamber and a piston rear defined between an outer peripheral surface of the piston and an inner peripheral surface of the cylinder and spaced apart in the axial direction And a switching valve mechanism for always connecting the piston front chamber to a high pressure circuit and a low pressure circuit, and a piston for striking by moving the piston back and forth in the cylinder. A hydraulic striking device for striking
The switching valve mechanism includes a valve chamber formed non-coaxially with the piston in the cylinder, a valve slidably fitted in the valve chamber, and constantly biasing the valve in one direction of forward and backward movement. A valve urging means that moves the valve in the opposite direction against the urging force of the valve urging means when pressure oil is supplied, and pressure oil is supplied to the piston rear chamber And an accumulator provided between the valve energizing means and the valve urging means and the valve control means,
The switching valve mechanism supplies and discharges pressure oil to and from the valve control means according to the forward / backward movement of the piston to move the valve forward and backward, and alternately pressurizes the piston rear chamber according to the forward / backward movement of the valve. A hydraulic striking device characterized in that the hydraulic oil is supplied and discharged so that the forward and backward movements of the piston are repeated by switching between a circuit and a low pressure circuit. A cylinder, a piston slidably fitted in the cylinder, a piston front chamber and a piston rear defined between an outer peripheral surface of the piston and an inner peripheral surface of the cylinder and spaced apart in the axial direction And a switching valve mechanism for always connecting the piston rear chamber to a high pressure circuit and a low pressure circuit, and a piston for striking by moving the piston back and forth in the cylinder. A hydraulic striking device for striking
The switching valve mechanism includes a valve chamber formed non-coaxially with the piston in the cylinder, a valve slidably fitted in the valve chamber, and constantly biasing the valve in one direction of forward and backward movement. A valve urging means that moves the valve in the opposite direction against the urging force of the valve urging means when pressure oil is supplied, and pressure oil is supplied to the piston rear chamber And an accumulator provided between the valve energizing means and the valve urging means and the valve control means,
The switching valve mechanism supplies and discharges pressure oil to and from the valve control means according to the forward and backward movement of the piston, and moves the valve forward and backward, and alternately increases the pressure of the piston front chamber according to the forward and backward movement of the valve. A hydraulic striking device characterized in that the hydraulic oil is supplied and discharged so that the forward and backward movements of the piston are repeated by switching between a circuit and a low pressure circuit.

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