JP2007196293A - Hammering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hammering device, automatically increasing the striking force when rock or the like to be crushed is hard. <P>SOLUTION: In this hammering device, a piston 2 having a pressure receiving surface 2u for hammering on which fluid pressure such as oil pressure acts in hammering and a pressure receiving surface 2w for reversal on which the fluid pressure acts in reversal is installed in a cylinder 1 so as to be moved forward and backward in the axial direction. An additional second pressure receiving surface 2v for hammering enabling pressurizing action on the fluid pressure is formed on the piston 2, and a switching means 101 is installed in the device to switch between a state in which the fluid pressure acting on the additional pressure receiving surface 2v can be supplied thereto and a state in which the fluid pressure cannot be supplied thereto. When the rebound of the piston 2 by a reaction caused when the piston 2 hits a chisel 3 at the movement end of the piston 2 is larger than a specified value, the switching means 101 switches the state to one in which the fluid pressure can be supplied to the additional pressure receiving surface 2v for hammering. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydraulic striking device, and more particularly to a striking device capable of adjusting a striking force according to the hardness of a rock or the like to be crushed.

Conventionally, as a striking device used for crushing rocks, etc., when an instantaneous flow rate flowing out to supply high-pressure fluid from the chamber to the circulation path is detected during the rebound stroke of the piston after striking, the control device There is a striking device that supplies pressurized fluid and moves the slide valve in a direction that lengthens the stroke of the piston (for example, Patent Document 1).
JP-A-8-216051

However, when the stroke of the piston of the conventional example is increased, it is necessary to open a plurality of passages along the axial direction of the cylinder on the cylinder side wall where the piston reciprocates, and the interval between the openings of the passages is reduced. Therefore, it is difficult to finely adjust the length of the piston stroke. For this reason, it has been difficult to finely adjust the amount of increase in striking force when the rock to be crushed is hard.
This invention is made | formed in view of such a point, The subject is a striking device which can adjust the increase amount of striking force when the hardness of the rock mass etc. to which it crushes is harder than the said prior art example. Is to provide.

In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a piston having an impact pressure receiving surface on which a fluid pressure such as oil pressure acts upon striking and a reversing pressure receiving surface on which the fluid pressure acts upon reversal is disposed in the cylinder. A striking device that is inserted so as to be capable of advancing and retreating in an axial direction, wherein a striking additional pressure receiving surface capable of pressurizing the fluid pressure is formed on the piston and acts on the additional pressure receiving surface. Switching means for switching between a state where fluid pressure can be supplied and a state where fluid pressure cannot be supplied is provided, and the rebound of the piston caused by the reaction when the piston strikes the chisel at the piston's moving end (striking point) exceeds a predetermined value. In the striking device, the switching means switches to a state in which the fluid pressure can be supplied to the striking additional pressure receiving surface when it is large.
As a result, the switching means for switching between the state in which the fluid pressure acting on the striking additional pressure receiving surface formed on the piston capable of pressurizing the fluid pressure can be supplied and the state in which the fluid pressure cannot be supplied is provided on the piston. When the piston rebounds when the piston hits the chisel at the advance end, the piston is switched to a state where the fluid pressure can be supplied to the additional pressure receiving surface for impact when the piston rebounds is larger than a predetermined value. When the rebound is larger than a predetermined value, the striking force received by the piston from the fluid pressure can be automatically increased. At this time, by adjusting the area of the additional pressure receiving surface, the amount of increase in impact force can be adjusted more finely than in the conventional example.

Furthermore, the invention described in claim 2 is that, in the invention described in claim 1, the switching means is controlled by the fluid pressure rising by the rebound.
Thereby, since the switching means is controlled by the fluid pressure that rises due to the rebound, it becomes easy for the switching means to detect the rebound.

Further, the invention described in claim 3 is the invention described in claim 2, in which the switching means is controlled by a first fluid path switching unit (for example, a switching valve) and a second fluid path switching unit. The first fluid path switching unit is controlled by the fluid pressure rising by the rebound, and the second fluid path switching unit supplies the fluid pressure to the additional pressure receiving surface for impact. It is to switch between the state and the non-supply state.
As a result, the first fluid path switching unit of the switching means is controlled by the fluid pressure rising by the rebound, and the fluid path is switched, and the second fluid path switching unit is subjected to the additional pressure receiving for impact by switching the fluid path. Since the fluid pressure is supplied to the surface, it is easy for the piston to automatically increase the striking force even when the change in hydraulic pressure due to the rebound is small.

According to the first aspect of the present invention, when the rock or the like to be crushed by the striking device is hard, the striking force for automatically crushing the rock or the like can be increased. It can be adjusted more finely than the conventional example.
Further, according to the invention described in claim 2, in addition to the effect of the invention described in claim 1, it becomes easy to detect that the rock is hard when the impact device crushes the rock.
Further, according to the invention described in claim 3, in addition to the effect of the invention described in claim 2, even when the change in hydraulic pressure due to the rebound of the piston when the rock mass to be crushed by the striking device is hard is small, the It becomes easy to increase the striking force for crushing the bedrock.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of the striking device according to the first embodiment, and FIGS. 2 to 4 sequentially show the operating states of the striking device.

As shown in FIG. 1, the striking device according to the first embodiment uses hydraulic pressure as the fluid pressure. A cylinder 1 that operates by hydraulic pressure and a piston 2 that slides on the inner wall of the cylinder 1 and can advance and retreat in the axial direction are provided. The piston 2 includes, in order from the right in the drawing, a minimum diameter portion 2a, a small diameter portion 2b having a diameter larger than the minimum diameter portion 2a, a first large diameter portion 2c, a groove-shaped communication portion 2d, a second large diameter portion 2e, and a medium diameter portion. 2f (the diameter is larger than the small diameter portion 2b and smaller than the large diameter portions 2c and 2e). The illustrated right end surface of the first large-diameter portion 2c is a ring-shaped impact pressure receiving surface 2u, and the illustrated right end surface of the small-diameter portion 2b is a ring-shaped impact additional pressure receiving surface 2v. Further, the illustrated left end surface of the second large diameter portion 2e is a ring-shaped reversal pressure receiving surface 2w. A chisel 3 is disposed on the left side of the intermediate diameter portion 2f of the piston 2 in the figure.
A high pressure chamber 4, a pilot chamber 5, a low pressure chamber 6, a first pressurizing chamber 7 and a second pressurizing chamber 8 are formed in the inner wall of the cylinder 1 in the shape of a ring from the left side in the drawing. Further, a gas sealing chamber 9 is formed at the right end of the cylinder 1 in the figure. The high pressure chamber 4, the pilot chamber 5, the low pressure chamber 6, the first pressurizing chamber 7, the second pressurizing chamber 8, and the gas sealing chamber 9 are each partitioned by the inner wall of the cylinder 1.

  The hydraulic pump 14 serving as a hydraulic pressure source is connected to the high pressure chamber 4 and arranged to be connectable to the first pressurizing chamber 7 via the first switching valve 11. The oil tank 15 is connected to the low pressure chamber 6 and is arranged to be connectable to the first pressurizing chamber 7 via the throttle valve 18 and the first switching valve 11. Here, the first switching valve 11 is arranged to switch the hydraulic path so as to connect either the hydraulic pump 14 or the oil tank 15 to the first pressurizing chamber 7. This switching is performed by the hydraulic pressure of the pilot chamber 5 applied to the pilot port of the first switching valve 11, and as shown in FIG. 1, the pilot chamber 5 communicates with the low pressure chamber 6 via the communication portion 2d. When the hydraulic pressure of 5 is low (the hydraulic pressure of the oil tank 15), the first switching valve 11 is in a state of connecting the oil tank 15 to the first pressurizing chamber 7 via the throttle valve 18. The throttle valve 18 functions to delay the decrease in the hydraulic pressure in the first pressurizing chamber 7. As shown in FIG. 2, the pilot chamber 5 is connected to the high pressure chamber 4 through the space between the medium diameter portion 2 f and the inner wall of the cylinder 1, and the pilot chamber 5 has a high hydraulic pressure (hydraulic pressure of the hydraulic pump 14). At this time, the first switching valve 11 switches to a state in which the hydraulic pump 14 is connected to the first pressurizing chamber 7.

The switching means 101 for switching the hydraulic pressure in the second pressurizing chamber 8 includes a second switching valve 12 and a third switching valve 13. The hydraulic pressure in the first pressurizing chamber 7 is connected so as to be applied to the pilot port of the second switching valve 12 via the check valve 16. A throttle valve 17 is connected in parallel to the check valve 16.
Here, the second switching valve 12 is arranged to switch the hydraulic path so as to connect either the hydraulic pump 14 or the oil tank 15 to the pilot port of the third switching valve 13. This switching is performed by the hydraulic pressure of the first pressurizing chamber 7 applied to the pilot port of the second switching valve 12, and as shown in FIG. 1, the hydraulic pressure of the first pressurizing chamber 7 is low (the hydraulic pressure of the oil tank 15). ), The second switching valve 12 is in a state of connecting the hydraulic pump 14 to the pilot port of the third switching valve 13.
Further, the third switching valve 13 is arranged to switch the hydraulic path so as to connect either the first pressurizing chamber 7 or the oil tank 15 to the second pressurizing chamber 8. This switching is performed by the hydraulic pressure applied to the pilot port of the third switching valve 13, and as shown in FIG. 1, when the hydraulic pressure of the pilot port is high (hydraulic pressure of the hydraulic pump 14), the third switching valve 13 Is in a state where the oil tank 15 is connected to the second pressurizing chamber 8, and as shown in FIG. 3, when the hydraulic pressure of the pilot port becomes low (the hydraulic pressure of the oil tank 15), the third switching valve 13 is The pressure chamber 7 and the second pressure chamber 8 are switched to a connected state.
An accumulator 19 is connected to the hydraulic pump 14.

The striking device having the above configuration operates as follows.
First, as shown in FIG. 1, at the time of start-up, the tip of the piston 2 (tip of the medium diameter portion 2f) is at the hit point (position where the chisel 3 is hit). At this time, the reversal pressure receiving surface 2w of the piston 2 receives a reversal force (force in the right direction in the figure) from the oil pressure of the high pressure chamber 4, and the striking pressure receiving surface 2u receives a force from the oil pressure (low pressure) of the first pressurizing chamber 7. The additional pressure receiving surface 2v does not receive a force (force in the left direction in the figure) from the hydraulic pressure (low pressure) in the second pressurizing chamber 8, so that the piston 2 moves in the right direction in the figure. It will be in the state of FIG.

  The state of FIG. 2 is a state in which the striking stroke is started. In this state, the tip of the piston 2 is at the top dead center, and the pilot chamber 5 communicates with the high-pressure chamber 4 through a gap between the inner wall of the cylinder 1 and the middle diameter portion 2f, so that the first switching valve 11 is switched. The hydraulic pressure in the first pressurizing chamber 7 becomes high. Note that the hydraulic pressure in the second pressurizing chamber 8 remains low. Since the area of the impact pressure receiving surface 2u receiving the hydraulic pressure of the first pressurizing chamber 7 is larger than the area of the reversing pressure receiving surface 2w receiving the hydraulic pressure of the high pressure chamber 4, the piston 2 moves to the left in the figure.

In the stage of transition from the state shown in FIG. 2 to the state shown in FIG. 3, the pilot chamber 5 communicates with the low pressure chamber 6, the first switching valve 11 is switched, and the first pressurizing chamber 7 is in the first state. Even when connected to the oil tank 15 via the switching valve 11 and the throttle valve 18, the hydraulic pressure in the first pressurizing chamber 7 is maintained at a substantially high pressure for a while due to the throttle valve 18. In this state, the rebound of the piston 2 that hits the chisel 3 that crushes the rock (not shown) becomes larger than a predetermined value, and the hydraulic pressure of the first pressurizing chamber 7 is higher than the high pressure (hydraulic pressure of the hydraulic pump 14) for this rebound. When the pressure exceeds a predetermined value and a high pressure, the second switching valve 12 switches to a state in which the oil tank 15 is connected to the pilot port of the third switching valve 13. As a result, the third switching valve 13 is switched, and the first pressurizing chamber 7 is connected to the second pressurizing chamber 8 via the third switching valve 13.
However, as described above, since the first pressurizing chamber 7 is connected to the oil tank 15 via the first switching valve 11 and the throttle valve 18, the first pressurizing chamber 7 and the second pressurizing chamber 8 The oil pressure gradually decreases and becomes the oil pressure of the oil tank 15. For this reason, as in the case of FIG. 1, the piston 2 moves to the right in the figure and enters the state of FIG.

  In the state of FIG. 4, the pilot chamber 5 communicates with the high pressure chamber 4 as in FIG. 2, so that the first switching valve 11 is switched and the hydraulic pump 14 is first pressurized via the first switching valve 11. The first pressurizing chamber 7 is connected to the second pressurizing chamber 8 via the third switching valve 13. For this reason, the hydraulic pressure in the first pressurizing chamber 7 and the second pressurizing chamber 8 becomes high. In this state, the striking pressure receiving surface 2u that receives the hydraulic pressure of the first pressurizing chamber 7 and the additional pressure receiving surface 2v that receives the hydraulic pressure of the second pressurizing chamber 8 both receive a leftward force in the figure, and the piston 2 is shown in FIG. The chisel 3 is struck by receiving a force in the left direction in the figure, which is a magnitude obtained by adding the force received by the additional pressure receiving surface 2v by the hydraulic pressure of the second pressurizing chamber 8 to the force in the case of At this time, the throttle valve 17 functions to delay the decrease in the hydraulic pressure of the pilot port of the second switching valve 12, so that the state of the second switching valve 12 is maintained until the piston 2 strikes the chisel 3. . Since the force received by the additional pressure receiving surface 2v is proportional to the area of the additional pressure receiving surface 2v, the force received by the additional pressure receiving surface 2v can be changed by changing the area of the additional pressure receiving surface 2v.

When the piston 2 moves leftward from the state shown in FIG. 2, the piston 2 strikes the chisel 3 and the chisel 3 crushes the rock, etc., and the rebound of the piston 2 is below the predetermined value, Since the hydraulic pressure in the first pressurizing chamber 7 becomes equal to or lower than the pressure higher than the high pressure (hydraulic pressure of the hydraulic pump 14), the second switching valve 12 and the third switching valve 13 are not switched. For this reason, since the oil tank 15 is connected to the second pressurizing chamber 8 via the third switching valve 13, the hydraulic pressure of the second pressurizing chamber 8 becomes low. In this state, when the piston 2 strikes the chisel 3, the hydraulic pressure in the second pressurizing chamber 8 does not increase the striking force.
In addition, as shown in FIG. 4, even after the second pressurizing chamber 8 becomes high pressure, the piston 2 moves to the left in the drawing, the piston 2 strikes the chisel 3 and the chisel 3 crushes the bedrock and the like. When the rebound of the piston 2 is equal to or less than the predetermined value, the hydraulic pressure in the first pressurizing chamber 7 is equal to or lower than the pressure higher than the high pressure (hydraulic pressure of the hydraulic pump 14) by the predetermined value. 12 is switched, the hydraulic pump 14 is connected to the pilot port of the third switching valve 13 via the second switching valve 12, the third switching valve 13 is switched, and the oil tank 15 is switched via the third switching valve 13. Connected to the second pressurizing chamber 8. For this reason, since the second pressurizing chamber 8 has a low pressure, the hydraulic pressure of the second pressurizing chamber 8 does not increase the striking force when the piston 2 strikes the chisel 3.

In this way, the switching means 101 that switches between the state in which the hydraulic pressure acting on the striking additional pressure receiving surface 2v formed on the piston 2 capable of pressurizing the hydraulic pressure can be supplied to the piston 2 is provided. When the rebound of the piston 2 due to the recoil when the piston 2 strikes the chisel 3 at the advancing end (striking point) is larger than a predetermined value, the additional pressure receiving surface 2v is switched to a state where the hydraulic pressure can be supplied. Therefore, when the rebound is larger than a predetermined value, the striking force received by the piston 2 from the hydraulic pressure can be automatically increased.
Furthermore, since the switching means 101 is controlled by the hydraulic pressure that rises due to the rebound, it becomes easy for the switching means 101 to detect the rebound.
Further, the second switching valve 12 serving as the first fluid path switching unit of the switching means 101 is controlled by the hydraulic pressure that rises due to the rebound and switches the oil path. By switching the oil path, the second fluid path switching unit is obtained. Since the third switching valve 13 supplies the hydraulic pressure to the additional pressure receiving surface 2v, it is easy to automatically increase the striking force that the piston 2 receives from the hydraulic pressure. Further, since the second switching valve 12 can be made smaller than the third switching valve 13, it is easy to make the second switching valve 12 integrally with the cylinder 1.

(Second Embodiment)
Furthermore, the second embodiment is as follows.
As shown in FIG. 5, the striking device according to the second embodiment is a modification of the first embodiment, and uses hydraulic pressure as the fluid pressure as in the first embodiment. A cylinder 21 that operates by hydraulic pressure and a piston 22 that can advance and retreat in the axial direction within the cylinder 21 are provided. The piston 22 includes a small-diameter portion 22a, a medium-diameter portion 22b having a diameter larger than that of the small-diameter portion 22a, a first large-diameter portion 22c having a diameter larger than that of the medium-diameter portion 22b, a groove-shaped communication portion 22d, and a medium-diameter portion. A second large diameter portion 22e having a diameter larger than 22b and a minimum diameter portion 22f having a diameter smaller than that of the small diameter portion 22a are provided. The illustrated right end surface of the first large-diameter portion 22c is a ring-shaped striking pressure receiving surface 22u, and the illustrated right end surface of the middle diameter portion 22b is a ring-shaped striking additional pressure receiving surface 22v. Furthermore, the illustrated left end surface of the second large diameter portion 22e is a ring-shaped reversal pressure receiving surface 22w. A chisel 23 is disposed on the left side of the minimum diameter portion 22f of the piston 22 in the figure.
On the inner wall of the cylinder 21, a second pressurizing chamber 28, a high pressure chamber 24, a pilot chamber 25, a low pressure chamber 26, and a first pressurizing chamber 27 are formed in a ring-shaped groove in order from the right side in the figure. Further, a gas sealing chamber 29 is formed at the right end of the cylinder 21 in the figure.

  The hydraulic pump 34 serving as a hydraulic pressure source is connected to the high pressure chamber 24 and is arranged to be connectable to the first pressurizing chamber 27 via the first switching valve 31. The low-pressure oil tank 35 is connected to the low-pressure chamber 26 and is arranged to be connectable to the first pressurizing chamber 27 via the first switching valve 31. Here, the first switching valve 31 is arranged to switch the hydraulic path so as to connect either the hydraulic pump 34 or the oil tank 35 to the first pressurizing chamber 27. This switching is performed by the hydraulic pressure of the pilot chamber 25 applied to the pilot port of the first switching valve 31, and as shown in FIG. 5, the pilot chamber 25 passes through the gap between the inner wall of the cylinder 21 and the medium diameter portion 22b. When the hydraulic pressure of the pilot chamber 25 is high (hydraulic pressure of the hydraulic pump 34) in communication with the high pressure chamber 24, the first switching valve 31 is in a state of connecting the hydraulic pump 34 to the first pressurizing chamber 27, as shown in FIG. As shown, when the pilot chamber 25 communicates with the low pressure chamber 26 via the communication portion 22d, and the hydraulic pressure in the pilot chamber 25 is low (hydraulic pressure in the oil tank 35), the first switching valve 31 causes the oil tank 35 to The state is switched to the state connected to the pressurizing chamber 27.

The switching means 102 that switches the hydraulic pressure in the second pressurizing chamber 28 includes a second switching valve 32 and a third switching valve 33. The hydraulic pressure in the high pressure chamber 24 is connected to the pilot port of the second switching valve 32 via the check valve 36. A throttle valve 37 is connected in parallel to the check valve 36. Here, the second switching valve 32 is arranged to switch the hydraulic path so as to connect either the hydraulic pump 34 or the oil tank 35 to the pilot port of the third switching valve 33. This switching is performed by the hydraulic pressure in the high-pressure chamber 24 applied to the pilot port of the second switching valve 32, and normally, as shown in FIG. 5, the second switching valve 12 normally connects the hydraulic pump 34 to the third switching valve 33. As shown in FIG. 7, the hydraulic pressure in the high pressure chamber 24 is higher than the high pressure (the hydraulic pressure of the hydraulic pump 34) due to the rebound of the piston 22, as shown in FIG. When it becomes higher than a predetermined value, the second switching valve 32 switches to a state in which the oil tank 35 is connected to the pilot port of the third switching valve 33. At this time, the throttle valve 37 functions to delay the decrease in the hydraulic pressure of the pilot port of the second switching valve 32.
Further, as shown in FIG. 5, the third switching valve 33 is arranged to switch the hydraulic path so as to connect either the hydraulic pump 34 or the oil tank 35 to the second pressurizing chamber 28. . This switching is performed by the hydraulic pressure applied to the pilot port of the third switching valve 33. When the hydraulic pressure of the pilot port of the third switching valve 33 is high (the hydraulic pressure of the hydraulic tank 34), the third switching valve 33 is When the oil tank 35 is connected to the second pressurizing chamber 28 and the hydraulic pressure of the pilot port of the third switching valve 33 becomes low pressure (hydraulic pressure of the oil tank 35) as shown in FIG. The valve 33 is switched to a state where the hydraulic pump 34 is connected to the second pressurizing chamber 28. An accumulator 38 is connected to the hydraulic pump 34, and an accumulator 39 is connected to the oil tank 35.

The striking device having the above configuration operates as follows.
First, as shown in FIG. 5, at the time of start-up, the tip of the piston 22 is at the hit point (position where the chisel 23 is hit), and the hydraulic pressure in the second pressurizing chamber 28 is low. At this time, the hydraulic pressure in the first pressurizing chamber 27 is high, and the reversing force (force in the right direction in the figure) received by the reversing pressure receiving surface 22 w of the piston 22 from the hydraulic pressure in the first pressurizing chamber 27 is the hydraulic pressure in the high pressure chamber 24. 6 is larger than the force received by the striking pressure receiving surface 22u of the piston 22 received from the left (force in the left direction in the figure), the piston 22 moves in the right direction in the figure and enters the state shown in FIG.

  The state of FIG. 6 is a state in which the striking stroke is started. In this state, the tip of the piston 22 is at the top dead center, and the pilot chamber 25 communicates with the low pressure chamber 26. Therefore, the first switching valve 31 is switched, and the hydraulic pressure in the first pressurizing chamber 27 is low. The hydraulic pressure in the second pressurizing chamber 28 remains low. Then, since the hydraulic pressure of the high pressure chamber 24 is received by the impact pressure receiving surface 22u, the piston 22 moves to the left in the drawing and strikes the chisel 23.

  When the chisel 23 struck by the piston 22 crushes a rock (not shown) or the like, if the rock or the like is hard, the piston 22 receives a rebounding force from the chisel 23 and instantaneously rebounds in the right direction in the figure. Due to the rebound of the piston 22, the hydraulic pressure in the high pressure chamber 24 instantaneously increases, and when the increase in the hydraulic pressure exceeds the predetermined value, the second switching valve 32 is switched, and thereby the third switching valve 33 is switched off. Instead, the state of FIG. 7 is obtained. For this reason, since the hydraulic pump 34 is connected to the second pressurizing chamber 28 via the third switching valve 33, the hydraulic pressure in the second pressurizing chamber 28 becomes high. In this state, the area of the reversal pressure receiving surface 22 w that receives the hydraulic pressure of the first pressurizing chamber 27 is the area of the impact pressure receiving surface 22 u that receives the hydraulic pressure of the high pressure chamber 24 and the additional pressure receiving surface that receives the hydraulic pressure of the second pressurizing chamber 28. Since it is larger than the total area of 22v, the piston 22 moves in the right direction in the figure and enters the state shown in FIG.

  In the state of FIG. 8, the tip of the piston 22 is at top dead center, and the pilot chamber 25 communicates with the low pressure chamber 26, so that the first switching valve 31 is switched and the oil tank 35 is connected via the first switching valve 31. Connected to the first pressurizing chamber 27. Therefore, the piston 22 strikes the chisel 23 by receiving the force in the left direction in the figure by the force of the impact pressure receiving surface 22u receiving the hydraulic pressure of the high pressure chamber 24 and the additional pressure receiving surface 22v receiving the hydraulic pressure of the second pressurizing chamber 28. .

In this way, the switching means 102 that switches between the state in which the hydraulic pressure acting on the striking additional pressure receiving surface 22v that can pressurize the hydraulic pressure formed in the piston 22 can be supplied and the state in which the hydraulic pressure cannot be supplied is provided. When the rebound of the piston 22 due to the recoil when the piston 22 strikes the chisel 23 at the advancing end (striking point) is greater than a predetermined value, the additional pressure receiving surface 22v is switched to a state where the hydraulic pressure can be supplied. Therefore, when the rebound is larger than a predetermined value, the striking force received by the piston 22 from the hydraulic pressure can be automatically increased. At this time, by adjusting the area of the additional pressure receiving surface 22v, it is possible to finely adjust the amount of increase in the striking force. Furthermore, since the switching means 102 is controlled by the hydraulic pressure that rises due to the rebound, it becomes easy for the switching means 102 to detect the rebound.
Further, as in the first embodiment, when the rebound of the piston 22 is not more than a predetermined value, the second switching valve 32 and the third switching valve 33 are switched so that the hydraulic pressure of the hydraulic pump 34 is applied to the additional pressure receiving surface 22v. It will not work.
Further, the second switching valve 32 serving as the first fluid path switching unit of the switching means 102 is controlled by the hydraulic pressure that rises due to the rebound and switches the oil path. By switching the oil path, the second fluid path switching unit is obtained. Since the third switching valve 33 supplies the hydraulic pressure to the additional pressure receiving surface 22v, it is easy to automatically increase the striking force received by the piston 22 from the hydraulic pressure. Further, since the second switching valve 32 can be made smaller than the third switching valve 33, it is easy to make the second switching valve 32 integrally with the cylinder 21.

(Third embodiment)
Furthermore, the third embodiment is as follows. The third embodiment is a modification of the second embodiment, FIG. 9 shows the characteristics of the striking device according to the third embodiment, and FIG. 10 shows the operating state of the striking device of FIG. .
The striking device according to the third embodiment shown in FIG. 9 uses hydraulic pressure as the fluid pressure as in the second embodiment. A cylinder 41 that operates by hydraulic pressure and a piston 42 that can advance and retreat in the axial direction in the cylinder 41 are provided. The piston 42 includes a first diameter portion 42a, a second diameter portion 42b having a diameter larger than that of the first diameter portion 42a, a third diameter portion 42c having a diameter larger than that of the second diameter portion 42b, and a groove-shaped communication portion. 42d, a fourth diameter part 42e having a diameter larger than that of the third diameter part 42c, and a fifth diameter part 42f having a diameter smaller than that of the fourth diameter part 42e. The illustrated right end surface of the third diameter portion 42c is a ring-shaped striking pressure receiving surface 42u, and the illustrated right end surface of the second diameter portion 42b is a ring-shaped striking additional pressure receiving surface 42v. Furthermore, the illustrated left end surface of the fourth diameter portion 42e is a ring-shaped reversal pressure receiving surface 42w. The area of the reversal pressure receiving surface 42w is formed larger than the sum of the area of the impact pressure receiving surface 42u and the area of the additional pressure receiving surface 42v. Further, a chisel 43 is disposed on the left side of the fifth diameter portion 42f of the piston 42 in the figure.
On the inner wall of the cylinder 41, a second pressurizing chamber 48, a high pressure chamber 44, a pilot chamber 45, a first low pressure chamber 46a, a second low pressure chamber 46b, and a first pressurizing chamber 47 are respectively provided in a ring-shaped groove from the right side in the figure. It is formed in a shape.
An oil tank (not shown) is connected to the first pressurizing chamber 47 via the first low pressure chamber 46 a, the second low pressure chamber 46 b and the first switching valve 51. In the state shown in FIG. 9, the first low pressure chamber 46a communicates with the second low pressure chamber 46b through a gap between the inner wall of the cylinder 41 and the third diameter portion 42c and the communication portion 42d. In the state shown in FIG. 10, the first low-pressure chamber 46a communicates with the second low-pressure chamber 46b through a gap between the inner wall of the cylinder 41 and the communication portion 42d. The rest is the same as in the second embodiment.

The striking device having the above configuration operates as follows.
First, at the time of starting shown in FIG. 9, high pressure is applied to the first pressurizing chamber 47 and the high pressure chamber 44, and low pressure is applied to the second pressurizing chamber 48, so that the piston 42 moves to the right in the drawing. As shown in FIG.
The state of FIG. 10 is a state at the start of hitting in which the tip of the piston 42 is at the top dead center. Since the piston 42 moves to the left in the drawing at the time of striking, the oil in the gap between the inner wall of the cylinder 41 on the left side of the drawing and the fifth diameter portion 42f from the pressure receiving surface 42w for reversal is transferred from the first pressurizing chamber 47 to the first switching valve 51. Further, by returning to the gap between the inner wall of the cylinder 41 and the communication portion 42d via the second low pressure chamber 46b, the resistance of the oil discharged from the first pressurizing chamber 47 can be reduced. For this reason, the speed at which the piston 42 moves in the left direction in the figure is increased, and the chisel 43 can be strongly hit. The rest is the same as in the second embodiment.

  In each of the above embodiments, the switching means 101 and 102 include the second switching valve and the third switching valve, respectively. However, the present invention is not limited to this, and the third switching valve is omitted. You may make it comprise only. However, in this case, when the momentary increase in hydraulic pressure due to the rebound of the piston exceeds a predetermined value, the pilot port of the third switching valve receives the momentary increase in hydraulic pressure due to the rebound of the piston, and the third switching It is necessary to make the valve switch. Furthermore, although the hydraulic pressure is used as the fluid pressure, it is not limited to the hydraulic pressure but may be an air pressure that can drive the piston.

It is explanatory drawing which shows the outline of the striking device which concerns on 1st Embodiment. It is explanatory drawing which shows the operation state of the striking device of FIG. FIG. 3 is an explanatory diagram illustrating an operation state continued from FIG. 2. FIG. 4 is an explanatory diagram illustrating an operation state continued from FIG. 3. It is explanatory drawing which shows the outline of the striking device which concerns on 2nd Embodiment. It is explanatory drawing which shows the operation state of the striking device of FIG. It is explanatory drawing which shows the operation state of a continuation of FIG. FIG. 8 is an explanatory diagram illustrating an operation state continued from FIG. 7. It is explanatory drawing which shows the characteristic of the striking device which concerns on 3rd Embodiment. It is explanatory drawing which shows the operation state of the striking device of FIG.

Explanation of symbols

1, 21, 41 Cylinder 2, 22, 42 Piston 2u, 22u, 42u Strike pressure receiving surface 2v, 22v, 42v Additional pressure receiving surface 2w, 22w, 42w Reversing pressure receiving surface 3, 23, 43 Chisel 11, 31, 51 First 1 switching valve 12, 32 2nd switching valve 13, 33 3rd switching valve 14, 34 Hydraulic pump 15, 35 Oil tank 101, 102 switching means

Claims (3)

A striking device in which a piston having a striking pressure receiving surface to which fluid pressure such as hydraulic pressure acts upon striking and a reversing pressure sensing surface to which the fluid pressure acts upon reversing is inserted into a cylinder so as to be capable of moving back and forth in the axial direction. There,
A switching means for switching between a state in which a fluid pressure acting on the additional pressure receiving surface can be supplied and a state in which the fluid pressure acting on the additional pressure receiving surface can be supplied are formed on the piston, wherein an additional pressure receiving surface capable of pressurizing the fluid pressure is formed. Provided,
The switching means can supply the fluid pressure to the additional pressure receiving surface for impact when the rebound of the piston due to the reaction when the piston strikes the chisel at the moving end of the piston is larger than a predetermined value. A striking device characterized by switching to a state. The striking device according to claim 1,
The striking device characterized in that the switching means is controlled by a fluid pressure that rises due to the rebound. A striking device according to claim 2,
The switching means includes a first fluid path switching unit and a second fluid path switching unit controlled by the first fluid path switching unit, and the first fluid path switching unit increases the fluid pressure by the rebound. And the second fluid path switching unit switches between a state in which the fluid pressure is supplied to the additional pressure receiving surface for impacting and a state in which the fluid pressure is not supplied.

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