WO2005000532A1

WO2005000532A1 - Hydraulic hammering device

Info

Publication number: WO2005000532A1
Application number: PCT/JP2004/008667
Authority: WO
Inventors: Osamu Hori; Atsushi Fujimoto
Original assignee: Konan Construction Machinery Co., Ltd.
Priority date: 2003-06-25
Filing date: 2004-06-14
Publication date: 2005-01-06
Also published as: DE112004001161T5; JP4488694B2; JP2005014134A

Abstract

A hydraulic hammering device for hammering a chisel by reciprocatively moving a hammering piston has a brake chamber, a stroke-regulating valve, and a holding mechanism. The brake chamber is turned to be a sealed-up chamber by the hammering piston when the piston moves in the hammering direction of the chisel by a predetermined distance beyond a regular hammering position. The stroke-regulating valve sends out a signal when a pressure in the brake chamber exceeds a predetermined value, which is done to shorten a stroke for a reduced hammering force. The holding mechanism holds the stroke-regulating valve at its switching position for predetermined time. The hydraulic hammering device also has a supplying mechanism. When the hammering piston is in the braking chamber at the time when hammering starts, the supplying mechanism supplies an operation fluid into the brake chamber to make the piston escape from the brake chamber.

Description

Description Hydraulic impact device Technical field

The present invention relates to a hydraulic striking device for striking a chisel by reciprocating a striking piston, and more particularly to a technique for automatically changing the stroke of a striking piston according to the hardness of an object to be struck. Background art

Conventionally, as a striking device that automatically changes the stroke of a striking biston according to the hardness of a striking object, for example, a striking device disclosed in Japanese Patent Publication No. 5-8531'1 is provided.

Specifically, the instantaneous pressure fluctuation in the chamber above or below the striking piston, which occurs at the moment of the impact of the impact piston, is compared with the reference pressure, and the control flow generated according to the pressure difference is determined by the operating means. We use as.

For example, the stroke of the striking piston is changed by changing the position of the stroke selection slide valve by changing the position of the spool that controls the discharge passage to change the operating pressure, or by changing the position of the stroke selection slide valve by a control flow rate corresponding to the pressure difference or the pressure. The number of hits or the number of hits is adjusted.

Therefore, in the above-described conventional apparatus, the function of holding the position of the spool / stroke selection slide valve and not releasing the position is added. Therefore, it is necessary to allow for considerable redundancy in order to capture the flow rate corresponding to the measured pressure difference and discharge it while holding the spool ゃ stroke selection slide valve in the required position until necessary. Was not efficient. In the case of a fluid whose viscosity changes with temperature, such as oil, the effect of the fluid temperature also has a large effect. Stroke control cannot be performed accurately.

Therefore, in order to solve the above problems, the present invention provides a hydraulic hitting device that automatically changes the next hitting stroke in accordance with the state of the main hitting and performs stroke control efficiently and accurately. With the goal. Disclosure of the invention

In order to achieve the above object, a hydraulic striking device according to the present invention is directed to a hydraulic striking device for striking a chisel by reciprocating a striking piston, wherein the striking biston exceeds a regular striking position. When moving a certain distance in the striking direction, reduce the striking force by shortening the stroke when the pressure in the brake chamber exceeds a predetermined value and the brake chamber, which is a room sealed by the striking biston. It is provided with a stroke control valve for issuing a signal and a holding mechanism for holding the stroke control pulp at the switching position for a predetermined time.

Further, in the above configuration, a supply mechanism that supplies a working fluid to the brake chamber so that the striking piston escapes from the brake chamber when the striking piston is in the brake chamber at the time of starting striking. Things. Brief Description of Drawings

FIG. 1 is a diagram showing the overall configuration of a hydraulic impact device of the present invention.

FIG. 2 is an enlarged view showing a circuit configuration of the hydraulic driving apparatus according to the present invention.

FIG. 3 is a diagram for explaining a stroke by a striking piston.

FIG. 4 is an enlarged view showing another circuit configuration in the hydraulic driving apparatus of the present invention. FIG. 5 is an enlarged view showing still another circuit configuration in the hydraulic impact device of the present invention. -Best mode for carrying out the invention Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment] ''

FIG. 1 shows the overall configuration of a hydraulic impact device of the present invention.

The impact device 1 is generally mounted as an attachment on construction equipment such as a hydraulic excavator, and uses a working fluid supplied from a hydraulic source to crush concrete or rock at a crushed stone pit in a civil engineering site. It is used at the time.

First, the outline of the striking device 1 will be described. The striking biston 2 has two pressure receiving surfaces PS 1 and PS 2 (PS 1> PS 2) having different areas, and the pressure receiving surface PS 2 having a small area has a hydraulic pressure source. A high pressure always acts through the hydraulic circuit, and a high pressure and a low pressure alternately act on the pressure receiving surface PS 1 having a large area from the hydraulic source through the hydraulic circuit. When a low pressure is acting on the pressure receiving surface PS1, the gas is compressed against the gas pressure acting on the pressure receiving surface PS0 at the uppermost part of the impact piston 2 due to the high pressure acting on the pressure receiving surface PS2. However, when the impact piston 2 performs a return stroke and a high pressure is acting on the pressure receiving surface PS1, the impact stroke is performed by the high pressure and the gas pressure acting on the pressure receiving surface PS1. Further, when the striking piston 2 is further lowered by a certain distance in the striking direction from a theoretically determined regular striking position, a brake chamber 13 is formed which is sealed by the striking piston 2.

Hereinafter, a specific configuration of the impact device 1 will be described.

In FIG. 1, C is a casing. The casing C is provided with a cylinder chamber C1 in which a striking piston 2 is slidably reciprocated in the axial direction, and is connected to one end (lower end) of the cylinder chamber C1. And a gas chamber C 3 connected to the other end (upper end side) of the cylinder chamber C 1 and filled with a gas such as nitrogen, for example. Has two large-diameter portions 2a and 2b formed at a predetermined distance from each other, and the peripheral surfaces of these two large-diameter portions 2a and 2b are slidably disposed in the cylinder chamber C1. Have been. The end surface of the upper shaft portion 2c connected to the large diameter portion 2a is the gas chamber C3. The end surface of the lower shaft portion 2d connected to the large diameter portion 2b is arranged facing the chisel chamber C2.

The upper and lower shaft portions 2c and 2d have a smaller diameter in the upper shaft portion 2c than in the lower shaft portion 2d. As a result, the pressure receiving surface PS1 of the large diameter portion 2a is smaller. The pressure receiving surface of the large diameter portion 2b is larger than PS2 (PS1> PS2).

Further, in the cylinder chamber C1, a plurality of grooves 4 to 8 are formed annularly in the axial direction. These grooves 4 to 8 are formed sequentially from the upper end (left end) to the lower end of the cylinder chamber C1. The groove 4 is formed facing the storage chamber 9 formed between the upper shaft portion 2c and the cylinder chamber C1, and the groove 8 is formed between the lower shaft portion 2d and the cylinder chamber C1. It is formed facing the accommodation room 10 to be formed. Grooves 5 and 6 are formed on the shaft portion 2e between the large-diameter portions 2a and 2b of the striking piston 2 when the striking piston 2 is located at the theoretical striking position L as shown in Fig. 1. The groove 5 is in communication with the tank T through the oil passage 12 and has a low pressure. On the other hand, a brake chamber 13 is formed in the cylinder chamber C1, which is the lower end side of the groove 8, and as shown in FIG. 1, when the impact piston 2 is arranged at the theoretical impact position L, the large-diameter section 2 is formed. The pressure receiving surface PS 2 of b is arranged without entering the brake chamber 13.

The grooves 4 to 8 and the brake chamber 13 are communicated with respective oil passages incorporated in a hydraulic circuit described later.

As described above, the chisel chamber C2 is a portion for accommodating the chisel 3, and the chisel 3 is disposed with its tip protruding a predetermined length, and the striking piston 2 moves to the theoretical striking position L. The striking piston 2 and the base end thereof are arranged so as to come into contact with each other.

The gas chamber C3 urges the impact piston 2 in the impact direction by the gas pressure sealed therein. That is, the end face of the upper shaft portion 2c facing the inside of the gas chamber C3 is formed as a pressure receiving surface PS0 that receives the gas pressure. Next, a specific configuration of the hydraulic circuit will be described with reference to FIG.

The discharge side of the hydraulic pump P is connected to a control valve 21 through an oil passage 20. An oil passage 22 and an oil passage 23 are branched from the oil passage 20. The oil passage 22 is communicated with one drive chamber CV2 of the control valve 21 and the oil passage 23 is connected to the groove. It is connected to 8.

The control valve 21 is a two-position switching type valve. The other drive chamber CV 1 is communicated with the groove 6 through an oil passage 24, and hydraulic pressure acting on the drive chamber CV 1 and the drive chamber CV 2 The signal switches between the upper position (circuit A) and the lower position (circuit B) in Figs. 1 and 2. -Specifically, in the A circuit, the control valve 21 cuts off the communication between the oil passage 20 and the oil passage 25 connected to the groove 4, and is connected to the oil passage 25 and the tank T. The oil passages 26 and are communicated. Therefore, when the control pulp 21 is disposed in the A circuit, the pressure in the storage chamber 9 is low because the groove 4 is communicated with the tank T.

When the control pulp 21 is in the B circuit, the oil passage 20 and the oil passage 25 are communicated with each other, whereby the working fluid from the hydraulic pump P is introduced into the storage chamber 9 through the groove 4. The storage chamber 9 is set to a high pressure.

In other words, the high pressure and the low pressure alternately act on the pressure receiving surface PS1 of the large diameter portion 2a by switching the control valve 21.

On the other hand, from the oil passage 23, oil passages 27 and 28 are branched, and the oil passage 27 is connected to the stroke control pulp 29, and the oil passage 28 is connected to the opening / closing valve 30. ing.

The stroke control valve 29 is a 2-position switching type pulp, and the drive chambers S V 1 and S

The position is switched between the upper position (B circuit) and the lower position (A circuit) in FIGS. 1 and 2 by the action of the hydraulic signal communicating with V 2 and S V 3 and the action of the spring S 1.

Specifically, when the stroke control valve 29 is in the B circuit, the oil passage 27 is in the drive chamber S

V 2 is communicated through an oil passage 31 and the drive chamber V 2 of the on-off valve 30 is connected to the oil passage. 32, is connected to the oil passage 2.6 through the oil passage 33 and communicates with the tank T.

When the stroke control valve 29 is a negative circuit, the oil passage 34 branched from the oil passage 25 is connected to the drive chamber SV 2 through the oil passage 31 and to the brake chamber 13. The oil passage 35 communicates with the drive chamber V 2 of the open / close pulp 30 through the oil passage 32.

In addition, an oil passage 38 further branched from the oil passage 28 branched from the oil passage 23 is connected to the drive chamber SVI of the stroke control valve 29.

Further, an oil passage 40 branched from the oil passage 35 is connected to the drive chamber SV 3 of the stroke control pulp 29.

The opening / closing valve 30 is a two-position switching type valve. The opening / closing valve 30 is moved to the left position (B circuit) in FIGS. Switch to the right position (A circuit).

Specifically, when the opening and closing pulp 30 is in the B circuit, the communication between the oil passage 28 and the oil passage 41 connected to the oil passage 35 is cut off, and the oil passage from the groove 7 is also cut off. The communication between 4 3 and the oil passage 4 2 communicating with the drive room CVI of the control pulp 21 is cut off.

In the A circuit, the on-off valve 30 connects the oil passage 28 to the oil passage 41 and also connects the oil passage 42 to the oil passage 43.

The drive chamber VI of the opening and closing pulp 30 communicates with the high-pressure oil passage 23 through an oil passage 45 branched from the oil passage 28.

Further, a throttle valve 46 is provided in the oil passage 28, and a check valve 47 is provided in the oil passage 41.

The details of the switching operation of each pulp based on each hydraulic signal will be described together with the operation of the hitting device 1 described below.

First, each valve immediately after the working fluid is introduced from the hydraulic pump P into the percussion device 1 is arranged in the following state.

In the control pulp 21, the drive room CV 1 is moved from the oil passage 24, groove 6, groove 5 The pressure is low due to communication with the tank T, and the driving room CV 2 is at a high pressure through the oil passage 22, so that the circuit A is in a state.

The stroke control pulp 29 has an A circuit by a spring S1 before the impact is started. Immediately after the working fluid is introduced, the oil passage 34 on the low pressure side communicates with the drive room SV 2 through the oil passage 31 so that the drive room SV 2 has a low pressure, and the drive rooms SV 1 and SV 3 is high pressure, and the relationship between the pressure receiving areas of these drive chambers SV1 and SV3 is preset to SV3> SVI, so that the stroke control pulp 29 holds the state of the A circuit.

The open / close valve 30 is always at a high pressure because the drive chamber V1 is supplied with the working fluid through the oil passages 28 and 45, and the drive chamber V2 is driven by the switching state of the stroke control valve 29. Changes to high and low pressure. Now, since the stroke control valve 29 is disposed in the A circuit as described above, the high pressure of the brake chamber 13 is guided to the drive chamber V2 through the oil passages 35 and 32 to become high. ing. Accordingly, although the driving chambers VI and V 2 are both at a high pressure, the relationship between the pressure receiving areas of the driving chambers VI and V 2 is set in advance to V 2> V 1, so that the on-off valve 30 is It is arranged in the state of the A circuit. When the working fluid is introduced from the hydraulic pump P in a state where the respective valves are arranged as described above, the pressure oil is introduced into the storage chamber 10 from the groove 8 through the oil passages 20 and 23. As a result, a high pressure acts on the pressure receiving surface PS2 of the large diameter portion 2b, and the return piston 2 moves to the left in FIG. 1 while compressing the gas sealed in the gas chamber C3. When the pressure receiving surface PS 2 of the large-diameter portion 2 b retreats to the position where the groove 8 communicates with the groove 7 by performing the return stroke, the working fluid introduced into the groove 8 from the oil passage 23 flows from the oil passage 23 to the oil passage. It is led to the on-off valve 30 through 43. At this time, since the open / close valve 30 is held in the A circuit, the working fluid passes through the open / close valve 30 and is introduced into the drive chamber C V 1 of the control pulp 21 through the oil passage 42.

At this time, the oil passage 24 communicated with the oil passage 42 is in a closed state because the groove 6 is closed by the 周 peripheral surface of the large diameter portion 2b of the impact piston 2. , Drive Since the relationship between the pressure receiving areas of the chambers CVl and CV2 is preset to CVl> CV2, the control pulp 21 switches to the state of the B circuit.

Therefore, the working fluid from the hydraulic pump P is introduced into the storage chamber 10 from the groove 8 through the oil passage 23, and is also introduced into the storage chamber 9 from the groove 4 through the oil passage 25. As a result, since the pressure receiving surface has a relationship of P S1> P S2, the impact process switches to the impact process in which the impact piston 2 moves to the right in FIG.

On the other hand, along with this, the oil passage 34 branched from the oil passage 25 also becomes high pressure, so that the high pressure also acts on the drive chamber SV 2 of the stroke control valve 29 arranged in the A circuit. As a result, the stroke control valve 29 is switched to the B circuit because the SV 1 + SV 2> SV 3 + panel S 1 force is preset.

When the stroke control pulp 29 is switched to the B circuit, the drive chamber V 2 of the on-off valve 30 is opened to a low pressure. When the driving chamber V2 has a low pressure, the opening / closing valve 30 is switched to the B circuit by the fluid pressure acting on the driving chamber V1.

Immediately before the hitting piston 2 hits the chisel 3, the grooves 6 and 5 communicate with each other through the annular groove 11 formed between the large-diameter portion 2 a and the large-diameter portion 2 b. It is. As a result, the oil passage 24 is opened to a low pressure through the oil passage 12, so that the drive chamber CV 1 of the control valve 21 connected to the oil passage 24 changes from high pressure to low pressure, and acts on the drive chamber CV 2. High pressure causes control valve 21 to begin switching to circuit A.

At this time, the impact piston 2 is sufficiently accelerated in the impact direction, and impacts the chisel 3 before the control valve 21 switches to the A circuit.

At this time, if the hitting target is hard, the chisel 3 does not cut into the hitting target. When the chisel 3 is not displaced in this way, the impact biston 2 does not further displace in the hitting direction of the chisel 3, and the theoretical strike position (normal strike position) L as shown in FIG. State.

Therefore, the pressure receiving surface PS 2 of the large diameter portion 2 b of the impact piston 2 does not enter the brake chamber 13 to seal the brake chamber 13. No high pressure higher than the operating high pressure is generated.

As a result, the drive chamber SV 3 of the stroke control pulp 29 does not apply a high pressure higher than the normal operating high pressure, and the stroke control pulp 29 maintains the state of the B circuit without switching from that position. .

Further, since the stroke control valve 29 holds the B circuit, high pressure does not act on the drive chamber V2 of the open / close pulp 30 as well, and the open / close valve 30 does not switch from that position and the B circuit is not operated. The state will be maintained.

After the striking piston 2 hits the chisel 3 in this way, since the control pulp 21 was switched to the A circuit, it was acting on the pressure receiving surface PS 1 of the large diameter portion 2a of the striking biston 2. The high pressure is returned to tank T through groove 4, oil passage 25, control pulp 21 and oil passage 26, which lowers the pressure in storage chamber 9.

Accordingly, the working piston supplied from the hydraulic pump P to the storage chamber 10 through the oil passages 20, 23 and the groove 8 causes the impact piston 2 to start a return stroke.

Even if the striking piston 2 retreats and the pressure receiving surface PS 2 of the large-diameter portion 2 b reaches the groove 7 and the grooves 8 and 7 communicate with each other, the on-off valve 30 remains in the state of the B circuit in the oil state. Since the passage 43 is blocked, high pressure does not act on the drive chamber CV 1 of the control valve 21 through the oil passage 43 and the oil passage 42, whereby the impact piston 2 continues the return stroke. I do. When the impact piston 2 further retreats and the pressure receiving surface PS 2 of the large diameter portion 2 b reaches the groove 6 and communicates with the groove 8, the working fluid introduced from the groove 8 flows from the groove 6 through the oil passage 24. Acts on the drive chamber CV 1 of the control valve 21 through As a result, the control pulp 21 is switched to the B circuit again, and the working fluid is introduced into the storage chamber 9 through the oil passage 25 and the groove 4. Accordingly, a high pressure is applied to the pressure receiving surface P S 1 of the large diameter portion 2a, and as a result, the impact piston 2 shifts to the impact stroke.

At this time, the force at which the oil passage 34 branched from the oil passage 25 also increases the pressure. The stroke control valve 29 is in the state of the B circuit, and the stroke control valve 29 is used to establish communication with the oil passage 31. There is no effect due to blocking. As a result, the striking piston 2 strikes the chisel 3 in the same manner as described above, and if the chisel 3 does not bite into the object to be struck, a high pressure equal to or higher than the normal operating high pressure is applied in the brake chamber 13 as described above. Does not occur. Therefore, the B circuit is maintained without switching the stroke control pulp 29 and the opening / closing valve 30, and the return stroke returns to the pressure receiving surface PS 2 of the large diameter portion 2 b to the groove 6 in the same manner as described above. Then, it shifts to the striking process again. In other words, when the hitting object is hard and the chisel 3 does not bite into the hitting object, the so-called long-stroke opening S 2 (the pressure receiving surface PS 2 of the large diameter portion 2 b returns to the groove 6 and shifts to the hitting stroke. (Refer to Fig. 3) The operation is repeated.

On the other hand, if the hitting object is soft or hard and the target is broken, the chisel 3 bites into the hitting object when hitting the chisel 3 with the hitting piston 2. Operation is performed.

When the chisel 3 bites into the object to be struck, the striking piston 2 is also displaced in the striking direction, so that the end face (pressure receiving surface PS 2) of the large diameter portion 2 b of the striking piston 2 exceeds the groove 8. The brake room 13 enters the brake room 13 and becomes a closed room. In other words, this is the case where the striking piston 2 has moved to the brake chamber 13 by the stroke S (—constant distance) shown in FIG.

As a result, the working fluid confined in the brake chamber 13 absorbs the kinetic energy of the impact piston 2 and its pressure increases, and this pressure acts on the drive chamber SV 3 of the stroke control pulp 29 through the oil passage 40. . Therefore, when the working fluid pressure that has risen in the brake chamber 13 exceeds the specified value and rises, and when SV3 + panel S1 force> SV1 + SV2, the stroke control valve 29 switches from circuit B to circuit A. Switch to.

As a result, an oil passage 34 branched from the oil passage 25 is connected to the drive chamber SV 2 of the stroke control valve 29 via the oil passage 31. At this time, if the switching of the control pulp 21 from the circuit B to the circuit A has been completed, since the oil passage 25 is at a low pressure, the drive chamber SV 2 of the stroke control valve 29 is also at a low pressure. Has become. Therefore, the stroke control valve 29 holds the state of the circuit A because SV 3> SVI. On the other hand, when the switching of the control pulp 21 from the circuit B to the circuit A has not been completed, since the oil passage 25 is still at a high pressure, the driving room SV 2 of the stroke control valve 29 is High pressure is acting as well. Therefore, the pressure from the brake chamber 13 acting on the drive chamber SV 3 is sufficiently higher than the normal operating pressure, so that the relationship SV 3 + spring S 1 force> SV 1 + SV 2 remains unchanged. The stroke control valve 29 holds the state of the circuit A.

In other words, in this situation, the stroke control valve 29 holds the state of the A circuit regardless of the switching state of the control valve 21.

As described above, since the stroke control pulp 29 is in the state of the circuit A, the high pressure from the brake chamber 13 is applied to the drive room V 2 of the opening / closing valve 30 by the oil passage 35, the stroke control valve 29, It will work through oil line 32. Accordingly, the open / close pulp 30 is switched from the circuit B to the circuit A in the drive chamber in the relation of V 2> V 1.

The switching of the open / close valve 30 to the A circuit causes the high-pressure working fluid from the hydraulic pump P to flow into the brake chamber 13 through the oil passages 23, 28, and 41. Since the pressure in the chamber 13 is higher than the pressure of the working fluid, the working fluid does not flow into the brake chamber 13.

Then, when the control pulp 21 is switched to the A circuit, the pressure in the storage chamber 9 becomes low through the oil passage 25, and the pressure acting on the pressure receiving surface PS 1 of the large diameter portion 2a of the impact biston 2 decreases. Therefore, the pressure in the brake chamber 13 also decreases. Therefore, when the pressure in the brake chamber 13 becomes lower than the pressure of the working fluid supplied from the hydraulic pump P, the working fluid flows into the brake chamber 13 through the oil passages 41 and 35 via the check valve 47. Inflow. As a result, the pressure receiving surface PS2 of the large-diameter portion 2b of the impact piston 2 quickly comes out of the brake chamber 13 to perform the return stroke described above.

However, in this return stroke, since both the stroke control pulp 29 and the opening and closing pulp 30 are in the state of the A circuit, when the pressure receiving surface PS 2 of the large diameter portion 2b reaches the groove 7, the process shifts to the impact stroke. This is the so-called short stroke S 1 (see FIG. 3). Based on the displacement of the chisel 3 when hitting the chisel 3 with the impact biston 2, the next stroke is automatically switched to either the short stroke S1 or the long stroke S2. Can be changed to In other words, the large-diameter portion 2b of the impact piston 2 moves a fixed distance to seal the brake chamber 13 and automatically changes the next impact stroke depending on whether high pressure is generated in the brake chamber 13. be able to. In addition, a mechanism (stroke control valve of the present invention is operated for a predetermined time at its switching position) comprising a stroke control valve 29 provided in the hydraulic circuit and an oil passage directly connected to the stroke control valve 29. The striking piston 2 is stroke-controlled by switching the control valve 21 through the open / close pulp 30 while holding the switching position of the stroke control vanoleb 29 by the holding mechanism that holds the stroke. The stroke control can be performed efficiently and accurately.

By the way, in the striking device 1 which operates as described above, the striking biston 2 is lowered to the lowest position by gas pressure before the striking starts, and the large diameter portion 2 b is in the brake chamber 13. There are cases. This often occurs, for example, when performing shaving operations.

In this case, the striking device 1 is returned to the normal striking operation as follows.

Before the start of the driving, the stroke control pulp 29 and the opening / closing valve 30 are both in the A circuit state by the springs S1 and S2.

In this state, when a high-pressure working fluid is introduced from the hydraulic pump P into the striking device 1, the control valve 21 is brought into the state of the A circuit by the high pressure guided to the driving room CV2, and the pressure receiving surface of the large-diameter portion 2a is formed. The pressure acting on PS 1 becomes lower.

On the other hand, although the working fluid is guided to the groove 8 through the oil passage 23, since the groove 8 is closed by the large-diameter portion 2b, the working fluid is supplied through the groove 8 to the pressure receiving surface of the large-diameter portion 2b. It is difficult to make it act directly on PS 2.

Therefore, the working fluid is guided to the brake chamber 13 through the oil passage 28 branched from the oil passage 23, the open / close pulp 30 and the oil passages 41, 35. receiving b Acts on the pressure surface PS2, causing the impact piston 2 to escape from the brake chamber 13 and start the return stroke. The mechanism including the on-off valve 30 and the oil passages 23, 28, 35, 41 here is a supply mechanism for supplying the working fluid to the brake chamber 13. In other words, even in such a case, by supplying the working fluid to the brake chamber 13 by the supply mechanism provided in the hydraulic circuit, the striking piston 2 is surely escaped from the brake chamber 13 to start the return stroke. be able to.

Also, this working fluid is used to drive the drive chamber SV 1 of the stroke control valve 29 through the oil passage 28, which is branched from the oil passage 23, and the opening / closing valve 30 through the oil passage 45. Chamber VI, drive room SV 3 for stroke control valve 29 via oil passage 28, open / close pulp 30, check valve 47 for oil passage 41, oil passage 40, and this drive room SV 3 In addition to the above, an oil passage 41, an oil passage 35, a stroke control pulp 29, and an oil passage 32 lead to a drive chamber V 2 of an on-off valve 30.

At this time, the panel S 2 of the opening / closing valve 30 determines the gas pressure when the striking piston 2 moves from the stop position before starting the striking until the gas is compressed and communicates with the brake chamber 13 and the groove 8. Considering the balance of the hydraulic pressure generated on the pressure receiving surface PS2 with respect to the pressure receiving surface PS0 of Biston 2, the force that substantially matches the driving force when the hydraulic pressure acts on the drive chamber V1 of the opening / closing valve 30 is considered. It is set so as to be urged in the direction facing the driving force. For this reason, the opening / closing valve 30 is maintained in the state of the A circuit until the impact biston 2 performs the return stroke and opens the groove 8.

On the other hand, since the pressure acting on the driving chamber SVI of the stroke control pulp 29 is set to be substantially the same as the pressure acting on the driving chamber SV 3, the stroke control valve 29 also has a relationship with the pressure receiving area and the panel. The state of the A circuit is held by S1.

Therefore, the return stroke at this time is a so-called short stroke S1, which shifts to a striking stroke when the pressure receiving surface PS2 of the large diameter portion 2b reaches the groove 7.

Thus, even if the large-diameter portion 2b of the striking piston 2 is biting into the brake chamber 13 before the striking starts, the chisel 3 is forcibly pressed and the striking piston It is possible to quickly start the impact without having to retreat the large diameter portion 2b of the motor 2 from the brake chamber 13 one by one.

[Second Embodiment]

FIG. 4 shows another circuit configuration of the hydraulic impact device of the present invention. The configurations of the casing, the impact biston, the chisel, etc., except for the hydraulic circuit described below, are the same as the configurations shown in the first embodiment, and will be described using the reference numerals described in the first embodiment.

This hydraulic circuit has a pulp configuration in which the stroke control valve and the opening and closing pulp of the hydraulic circuit described in the first embodiment are combined, and will be specifically described below.

The discharge side of the hydraulic pump P is connected to a control valve 21 through an oil passage 20. An oil passage 22 and an oil passage 23 are branched from the oil passage 20.The oil passage 22 is connected to one drive chamber CV2 of the control pulp 21 and the oil passage 23 is connected to the groove. It is connected to 8.

The control valve 21 is a two-position switching type valve. The other drive chamber CV 1 is communicated with the groove 6 through an oil passage 24, and hydraulic pressure acting on the drive chamber CV 1 and the drive chamber CV 2 The signal switches between the upper position (A circuit) and the lower position (B circuit) in Fig. 4.

Specifically, in the control pulp 21 in the A circuit, the communication between the oil passage 20 and the oil passage 25 connected to the groove 4 is cut off, and the oil passage connected to the oil passage 25 and the tank T is shut off. Communicate with 26. Accordingly, when the control valve 21 is disposed in the A circuit, the groove of the storage chamber 9 is communicated with the tank T and the pressure is low.

Further, when the control valve 21 is in the B circuit, the oil passage 20 and the oil passage 25 are communicated, whereby the working fluid from the hydraulic pump P is introduced into the storage chamber 9 through the groove 4. The storage chamber 9 is set to a high pressure.

In other words, the pressure receiving surface PS 1 of the large-diameter portion 2 a is alternately changed by switching the control pulp 21. High and low pressures act on

On the other hand, an oil passage 50 branches off from the oil passage 23, and the oil passage 50 communicates with the stroke control pulp 51.

The stroke control pulp 51 is a two-position switching type pulp. The upper position (circuit B) and the lower position in FIG. 4 are controlled by the hydraulic signals communicating with the drive chambers SV1, SV2 and SV3, and the action of the panel S3. Switch to position (A circuit).

Specifically, when the stroke control valve 51 is in the B circuit, the oil passage 50 is connected to the drive chamber SVI through the oil passage 52, and the oil passage 53 branched from the oil passage 50 is connected to the drive chamber. It is connected to SV 2 through oil line 55.

When the stroke control valve 51 is in the A circuit, the oil passage 50 communicates with the drive chamber SV 1 through the oil passage-52, and the oil passage 56 branched from the oil passage 53 drives the brake chamber 13. The oil passage 57 communicated with the oil passage 57 communicated with the chamber SV 3 through the oil passage 59 provided with the check valve 58 is connected to the oil passage 60 branched from the oil passage 25. The oil passage 61 communicated through the oil passage 5 and further communicated with the groove 7 is communicated with the oil passage 24 through the oil passage 62.

In addition, an oil passage 52 provided with a check valve 63 is branched from an oil passage 52 connected to the drive chamber SV 1 of the stroke control valve 51, and is connected to the oil passage 23. I have.

The details of the switching operation of each valve based on each hydraulic signal will be described together with the operation of the striking device 1 described below.

First, each valve immediately after the high-pressure working fluid is introduced from the hydraulic pump P into the striking device 1 is arranged in the following state.

In the control pulp 21, the driving room CV 1 is connected to the tank T from the oil passage 24, the groove 6, and the groove 5 through the oil passage 12 to a low pressure, and the driving room CV 2 has a high pressure through the oil passage 22. It is in the state of the A circuit because it is.

The stroke control pulp 51 is in the A circuit by the panel S3 before the impact is started. Immediately after the high-pressure working fluid is introduced, the oil passage 60 on the low-pressure side The driving room SV2 is connected to the driving room SV2 through 55 and the driving room SV2 is at a low pressure, the driving rooms SV1 and SV3 are at a high pressure, and the relationship between the pressure receiving areas of these driving rooms SVI and SV3 is SV3> Since the stroke control valve 51 is set in advance to SV1, the stroke control valve 51 maintains the state of the A circuit.

When the working fluid is introduced from the hydraulic pump P in a state where the respective valves are arranged as described above, the pressure oil is introduced into the storage chamber 10 from the groove 8 through the oil passages 20 and 23. As a result, a high pressure acts on the pressure receiving surface PS2 of the large diameter portion 2b to perform a return stroke in which the impact piston 2 moves while compressing the gas sealed in the gas chamber C3.

When the pressure receiving surface PS2 of the large-diameter portion 2b retreats to the position where the groove 8 communicates with the groove 7 by performing the return stroke, the working fluid introduced into the groove 8 from the oil passage 23 The control pulp 21 is introduced into the drive chamber CV 1 through the stroke control valve 51 and the oil passages 62 and 24. ''

At this time, the oil passage 24 communicated with the oil passage 62 is closed because the groove 6 is closed by the peripheral surface of the large-diameter portion 2b of the impact piston 2, and the drive chamber CV 1 Since the relationship between the pressure receiving area and CV 2 is set in advance to CV 1> CV 2, the control valve 21 switches to the state of the B circuit.

Accordingly, the working fluid from the hydraulic pump P is introduced from the groove 8 into the storage chamber 10 through the oil passage 23, and is also introduced into the storage chamber 9 from the groove 4 through the oil passage 25. As a result, since the pressure receiving surface has a relationship of P S 1> P S 2, the impact piston 2 is switched to the impact stroke.

On the other hand, along with this, the oil passage 60 branched from the oil passage 25 also has a high pressure, so that the high pressure also acts on the drive chamber SV 2 of the stroke control pulp 51 arranged in the A circuit. Since 3 ¥ 1 + 3 "^ 2> 3 ¥ 3 + Spring 31 force is preset, the stroke control valve 51 switches to the B circuit.

Immediately before the striking piston 2 performing the striking stroke hits the chisel 3, the grooves 6 and 5 are communicated with each other through the annular groove 11 formed between the large-diameter portion 2a and the large-diameter portion 2b. It is. As a result, the oil passage 24 is opened to a low pressure through the oil passage 12, so that the drive chamber CV 1 of the control valve 21 connected to the oil passage 24 changes from high pressure to low pressure, and acts on the drive chamber CV 2. High pressure causes control pulp 21 to begin switching to circuit A.

At this time, the striking piston 2 is sufficiently accelerated in the striking direction, and strikes the chisel 3 before the control lever 21 switches to the A circuit.

At this time, if the hitting target is hard, the chisel 3 does not cut into the hitting target. When the chisel 3 is not displaced in this manner, the impact biston 2 does not further displace in the hitting direction of the chisel 3, and the theoretical striking position (regular striking position) L as shown in FIG. State.

Therefore, the pressure receiving surface PS 2 of the large diameter portion 2 b of the impact piston 2 does not enter the brake chamber 13 to seal the brake chamber 13, so that the brake chamber 13 has a pressure higher than the normal operating high pressure. No high pressure is generated.

As a result, the drive chamber SV3 of the stroke control valve 51 is not subjected to a high pressure equal to or higher than the normal operating high pressure, and the stroke control valve 51 maintains the state of the B circuit without switching from that position.

After the striking piston 2 hits the chisel 3 in this manner, the control valve 21 was switched to the A circuit, and thus acted on the pressure-receiving surface PS 1 of the large-diameter portion 2a of the striking piston 2. The high pressure is returned to the tank T through the groove 4, the oil passage 25, the control valve 21 and the oil passage 26, whereby the pressure in the storage chamber 9 becomes low. ,

Accordingly, the striking piston 2 starts a return stroke again by the working fluid supplied from the hydraulic pump P to the storage chamber 10 through the oil passages 20, 23, and the groove 8.

Even if the impact piston 2 recedes and the pressure receiving surface PS2 of the large diameter portion 2b reaches the groove 7 and the grooves 8 and 7 communicate with each other, the stroke control valve 51 remains in the state of the B circuit in the oil state. Since the passage 61 is shut off, no high pressure acts on the drive chamber CV 1 of the control pulp 21 through the oil passage 61 and the oil passages 62, 24, whereby the striking piston 2 returns. Continue the process. When the impact piston 2 further retreats and the pressure receiving surface PS 2 of the large diameter portion 2 b reaches the groove 6 and communicates with the groove 8, the working fluid introduced from the groove 8 flows from the groove 6 through the oil passage 24. Acts on drive chamber CV 1 of control valve 21. As a result, the control valve 21 is switched to the regeneration B circuit, and the working fluid is introduced into the storage chamber 9 through the oil passage 25 and the groove 4. Accordingly, a high pressure is applied to the pressure receiving surface PS1 of the large diameter portion 2a, and as a result, the impact piston 2 shifts to an impact stroke.

As a result, the striking piston 2 strikes the chisel 3 in the same manner as described above, and if the chisel 3 does not bite into the object to be struck, a high pressure equal to or higher than the normal operating high pressure is applied in the brake chamber 13 as described above. Does not occur. Accordingly, the stroke control pulp 51 also maintains the B circuit without switching, and the return stroke returns to the groove 6 with the pressure receiving surface PS 2 of the large-diameter portion 2b returning to the groove 6 in the same manner as described above. . That is, when the hitting object is hard and the chisel 3 does not bite into the hitting object, the so-called long stroke S 2 (FIG. 3) in which the pressure receiving surface PS 2 of the large diameter portion 2 b returns to the groove 6 and shifts to the hitting stroke. (Refer to the above).

On the other hand, when the hitting target is soft or hard and the target is broken, the chisel 3 digs into the hitting target when hitting the chisel 3 with the hitting piston 2. Operation is performed.

The striking piston 2 is similarly displaced in the striking direction as the chisel 3 bites into the striking object, whereby the pressure receiving surface PS 2 of the large diameter portion 2b passes through the groove 8 and enters the brake chamber 13 to cause the striking. The brake room 13 becomes a closed room. In other words, the case where the impact biston 2 is displaced toward the brake chamber 13 by the stroke S (—constant distance) shown in FIG.

As a result, the working fluid confined in the brake chamber 13 absorbs the kinetic energy of the striking biston 2 and its pressure increases, and this pressure acts on the drive chamber SV 3 of the stroke control pulp 51 through the oil passage 57. I do. Therefore, the pressure of the working fluid that has risen in the brake chamber 13 exceeds a predetermined value and increases, and the SV 3 + panel S 3 force> SV 1 + SV 2 When this happens, the stroke control pulp 51 switches from circuit B to circuit A.

As a result, an oil passage 60 branched from the oil passage 25 is connected to the drive chamber SV2 of the stroke control pulp 51 via the oil passage 55. At this time, if the switching of the control valve 21 from the circuit B to the circuit A has been completed, since the oil passage 25 is at a low pressure, the drive chamber SV 2 of the stroke control valve 51 is also at a low pressure. Has become. Therefore, the stroke control valve 51 holds the state of the circuit A because S V 3> S VI is set.

On the other hand, if the switching of the control pulp 21 from the circuit B to the circuit A has not been completed, since the oil passage 25 is still at a high pressure, the drive chamber SV 2 of the stroke control valve 51 is provided with a drive chamber. High pressure works like SVI. Therefore, the pressure from the brake chamber 13 acting on the drive chamber SV 3 is sufficiently higher than the normal operating pressure, so that the relationship SV 3 + panel S 3 force> SV 1 + SV 2 remains unchanged. The stroke control valve 51 holds the state of the circuit A.

That is, in this situation, the stroke control valve 51 maintains the state of the A circuit regardless of the switching state of the control pulp 21.

The switching of the stroke control pulp 51 to the circuit A causes the high-pressure working fluid from the hydraulic pump P to flow into the brake chamber 13 through the oil passages 23, 50, 56, 59, 57. The working fluid does not flow into the brake chamber 13 because the pressure in the brake chamber 13 is higher than the pressure of the working fluid.

Then, when the control pulp 21 is switched to the A circuit, the pressure in the accommodation chamber 9 becomes low through the oil passage 25, and the pressure acting on the pressure receiving surface PS 1 of the large diameter portion 2a of the impact piston 2 decreases. Therefore, the pressure in the brake chamber 13 also decreases. Therefore, when the pressure in the brake chamber 13 drops below the pressure of the working fluid supplied from the hydraulic pump P, the working fluid flows into the brake chamber 13 through the check valves 58 and the oil passages 59 and 57. Inflow. As a result, the pressure receiving surface PS2 of the large-diameter portion 2b of the impact piston 2 quickly comes out of the brake chamber 13 to perform the return stroke described above.

However, in this return stroke, since the stroke control valve 51 is in the state of the A circuit, When the pressure receiving surface PS2 of the large-diameter portion 2b reaches the groove 7, a so-called short stroke S1 (see FIG. 3) is made, which shifts to the impact stroke.

In this manner, the next stroke is automatically changed to either the short stroke S1 or the long stroke S2 based on the displacement of the chisel 3 when the chisel 3 is hit with the striking biston 2. Can be. In other words, the large-diameter portion 2b of the impact piston 2 moves a certain distance to seal the brake chamber 13 and automatically change the next impact stroke depending on whether or not high pressure is generated in the brake chamber 13. Can be.

Also, a mechanism comprising a stroke control valve 51 provided in the hydraulic circuit and an oil passage directly connected to the stroke control valve 51 (the stroke control valve according to the present invention is moved for a predetermined time at its switching position). The stroke control of the striking piston 2 is performed by switching the control pulp 21 by holding the switching position of the stroke control valve 51 by the holding mechanism that holds the stroke, thereby performing the stroke control efficiently and accurately. be able to.

By the way, in the striking device 1 that operates as described above, before the striking starts, the striking biston 2 descends to the lowest position due to the gas pressure, and the large diameter portion 2 b enters the brake chamber 13. May be. This often occurs, for example, when performing shaving operations.

Before starting the impact, the stroke control pulp 51 is in the state of the circuit A by the panel S3.

In this state, when a high-pressure working fluid is introduced from the hydraulic pump P to the striking device 1, the control valve 21 is brought into the state of the A circuit by the high pressure guided to the drive room CV2, and the pressure receiving surface of the large-diameter portion 2a is formed. The pressure acting on PS 1 becomes lower.

On the other hand, although the working fluid is guided to the groove 8 through the oil passage 23, the working fluid is received by the large diameter portion 2b through the groove 8 because the groove 8 is closed by the large diameter portion 2. It is difficult to make it act directly on the pressure surface PS2. The hydraulic fluid is guided to the brake chamber 13 through the oil passage 50, the oil passage 56, the stroke control pulp 51, and the oil passages 59, 57 branched from the oil passage 23. The working fluid acts on the pressure receiving surface PS2 of the large-diameter portion 2b, thereby causing the percussion biston 2 to escape from the brake chamber 13 and start the return stroke. The mechanism including the stroke control valve 51 and the oil passages 50, 56, 57, 59 is a supply mechanism for supplying the working fluid to the brake chamber 13. That is, even in such a case, by supplying the working fluid to the brake chamber 13 by the supply mechanism provided in the hydraulic circuit, the driving piston 2 can be surely escaped from the brake chamber 13 to start the return stroke. Can be. The working fluid is supplied to the drive chamber SV 1 of the stroke control valve 51 through the oil passage 50 and the oil passage 52 branched from the oil passage 23, and to the oil passages 50, 56, and the stroke control. It is led to the drive chamber SV 3 of the stroke control valve 51 via the valve 51 and the oil passages 59 and 57. Since the force acting on the drive room SV1 of the stroke control pulp 51 is set to be smaller than the force acting on the drive room SV3, the stroke control pulp 51 It is held in the state of the A circuit in combination with the force.

Therefore, the return stroke at this time is a so-called short stroke S1, which shifts to an impact stroke when the pressure receiving surface PS2 of the large diameter portion 2b reaches the groove 7.

As a result, even if the large-diameter portion 2b of the impact piston 2 is biting into the brake chamber 13 before the impact starts, the chisel 3 is forcibly pressed to brake the large-diameter portion 2b of the impact piston 2. It is possible to quickly start the impact without having to retreat from the room 13 one by one.

FIG. 5 shows another circuit configuration of the hydraulic impact device of the present invention.

This circuit configuration is a slightly simplified version of the circuit configuration shown in FIG. 2, and unless the first shot of the impact biston 2 is a short stroke as described in FIG. 2, this circuit configuration is also used. The operation of the percussion biston 2 can be controlled in the same manner as described above. Specifically, the oil passage 38 shown in FIG. 2 is eliminated, and an oil passage 36 branched from the oil passage 23 communicates with the drive chamber SV 1 of the stroke control valve 29. Also, Panel S 1 has also been abolished.

As a result, the first stroke of the striking piston 2 does not always have a short stroke as in the circuit configuration shown in FIG. 2, but may have a longer stroke due to the stop position of the stroke control valve 29 before the striking starts. After the second shot, if the previous hit hits Biston 2 into the brake chamber 13, the next hit will be a shot stroke, and if it does not enter the brake chamber 13, the next hit will be a long stroke Thus, the same control as the circuit configuration shown in FIG. 2 'can be performed.

Note that, as described above, this circuit configuration is only slightly simplified from the circuit configuration shown in FIG. 2, and therefore, the same reference numerals are used for valves and oil passages having the same configuration as the circuit configuration described in FIG. The detailed description is omitted.

As described above, according to the hydraulic striking device of the present invention, the next striking stroke is either a short stroke or a long stroke based on the displacement of the chisel when striking chizenore with the striking biston. Can be changed automatically. Further, by controlling the stroke of the striking biston while holding the switching position of the stroke control valve by the holding mechanism provided in the hydraulic circuit, the stroke control can be performed efficiently and accurately.

Further, by supplying the working fluid to the brake chamber by the supply mechanism, it is possible to reliably cause the impact biston to escape from the brake chamber and start the return stroke. As a result, even if the striking piston enters the brake chamber before starting the striking operation, the striking operation can be quickly started without having to forcibly press the chisel to retract the striking biston from the braking chamber. Can be done.

It should be noted that the present invention can be implemented in other various forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in every aspect, and should not be construed as limiting. The scope of the present invention is defined by the appended claims, and is not restricted by the specification. Furthermore, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention. In addition, this application claims priority based on Japanese Patent Application No. 2003-18080726 filed in Japan on June 25, 2003. By reference to this, the entire contents are incorporated into the present application. Industrial applicability

The hydraulic impact device according to the present invention is generally applicable to machines in fields such as construction and civil engineering.

Claims

The scope of the claims

1. In a hydraulic hitting device that hits a chisel by reciprocating the hitting piston, when the hitting piston moves beyond a regular hitting position in the hitting direction of the chisel by a certain distance, the hitting piston is sealed. A brake chamber serving as a room, a stroke control valve for issuing a signal to shorten the stroke and reduce the striking force when the pressure in the brake chamber exceeds a predetermined value,

And a holding mechanism for holding the stroke control valve at the switching position for a predetermined time.

2. A supply mechanism for supplying a working fluid to the brake chamber so that the striking piston can escape from the brake chamber when the striking piston is in the brake chamber at the time of starting striking. The hydraulic hitting device according to claim 1.