JP2002210414A - Vibration generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration generator which surely vibrates with a prescribed stroke even when a piston undergoes large external force, and is improved in efficiency. SOLUTION: This vibration generator is provided with a self-holding means for holding the 1st change-over position or the 2nd change-over position which is the present position of a change-over valve 8 when a control valve 7 is at an intermediate position where it does not supply pilot pressure to a pilot pressure receiving face 9b of a spool.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use in, for example, vibrations generated in civil engineering and construction machines for performing soil compaction work, rubble of cultivated land, driving / pulling of piles, or crushing work. The present invention relates to a vibration generating device used for a vehicle.

[0002]

2. Description of the Related Art It is known that, when performing the above-mentioned various operations, the efficiency of the operation can be improved by attaching a vibration generating device to the tip end of the operation device. Various types of vibration generating devices are known, and as a vibration generating device that self-excitably generates vibration using self-pressure, there is one described in, for example, JP-A-2000-37661.

In the vibration generating device described in this publication, a reciprocating piston is provided so as to partially protrude from a body, and the piston always has a first pressure receiving surface having a small area on one side and a first oil chamber on the hydraulic pressure source side. The second pressure receiving surface having a large area on the opposite side is reciprocated depending on whether it is connected to the oil chamber of the second pressure receiving surface or to the tank port. This is performed by moving the spool of the switching valve provided in the above. The switching of the switching valve is performed by the action of the pilot pressure from the hydraulic pressure source on the switching valve and the disappearance of the pilot pressure by the movement of the control valve linked to the piston.

[0004]

However, in the above-described conventional vibration generator, when the piston is switched to the second switching position where the pilot pressure to the switching valve has disappeared, the piston receives a large resistance load. In this state, immediately after the spool of the switching valve is switched to the second switching position, the piston is rapidly pushed back by the resistive load, and the spool of the control valve is in the neutral position. A first switching position at which the pilot pressure of
There is a possibility that the pilot pressure may be held at a position in the middle of switching between the second switching position and the lost switching position.

[0005] When the spool of the switching valve is held at the position in the middle of switching in this way, the spool of the switching valve is affected by the fluid force due to the rapid flow of the hydraulic oil flowing from the second oil chamber to the tank port. Receives strong closing power. In addition to this, if the spool of the switching valve is momentarily switched to the first switching position before the spool of the control valve is switched to the second switching position due to the influence of the pulsation of the hydraulic oil due to the vibration operation, the piston Returns to its original position.

That is, there is a possibility that the piston has a stroke smaller than the specified vibration stroke and sufficient vibration cannot be obtained. Even if the spool of the switching valve is in the middle position, the piston vibrates, but even in this case, a sufficient opening is not obtained to allow the hydraulic oil to pass through the switching valve, resulting in a large pressure loss. As a result, the operation of the piston is slowed, and the efficiency is reduced.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a vibration generator capable of reliably vibrating at a predetermined stroke even when a piston receives a large external force, and improving the efficiency.

[0008]

According to the first aspect of the present invention, there is provided a vibration generator, which is provided in a body of the vibration generator so as to be reciprocally movable,
A piston having a first pressure-receiving surface having a small pressure-receiving area and a second pressure-receiving surface having a pressure-receiving area larger than the pressure-receiving surface; and a piston positioned on the first pressure-receiving surface side of the piston and defined in the body, A first oil chamber connected to a hydraulic pressure source, a second oil chamber defined in the body located on the second pressure receiving surface side of the piston, and an operation supplied and discharged to a hydraulic pilot unit A first switching position in which the second oil chamber communicates with the first oil chamber to move the piston toward the first oil chamber according to a pilot pressure of oil; and the second oil chamber. And a hydraulic pilot type switching valve that selectively switches to a second switching position that moves the piston to the second oil chamber side by communicating with the tank, and operates in conjunction with the piston, and the piston operates the piston. When moving to the first oil chamber side and reaching a predetermined position, the hydraulic pilot type switching valve When the pilot pressure is set to a low pressure, the switching valve is switched to the second switching position, and when the piston moves to the second oil chamber side and reaches a predetermined position, the hydraulic pressure from a hydraulic pressure source is changed to the hydraulic pilot type switching valve. A control valve that operates as a pilot pressure to switch the switching valve to the first switching position, wherein the control valve is at an intermediate position where the pilot pressure is not supplied to the pilot portion of the switching valve. And a self-holding means for holding the first switching position or the second switching position, which is the current position of the switching valve, as they are, respectively.

If such a self-holding means is provided, even if the piston receives an external force such as a large resistance load, the switching valve is reliably switched to a predetermined switching position by the self-holding means, thereby preventing malfunction of the piston. It can vibrate reliably with a predetermined vibration stroke.

According to a second aspect of the present invention, in the first aspect, the self-holding means is provided on an inner wall of a sliding hole of a spool of the switching valve and communicates with a high-pressure port and a tank which can communicate with a hydraulic pressure source. A possible low-pressure port, a large-diameter portion provided at an intermediate portion of the spool of the switching valve, and a large-diameter portion provided between the large-diameter portion and a large-diameter portion having a pilot pressure receiving surface at an end face of the spool, and provided on the spool An oil passage control unit that is provided on a spool of the control valve and communicates and shuts off an oil passage communicating with the high-pressure port and an oil passage communicating with the low-pressure port. When the pilot pressure receiving surface of the spool of the switching valve is at the first switching position that has received high-pressure hydraulic oil, the small-diameter portion of the spool of the switching valve faces the high-pressure port, The oil passage control unit opens an oil passage connected to the high pressure port, and when the piston moves to a control position where the control valve reverses the switching valve, the oil passage control unit connects to the high pressure port. When the connecting oil path is closed and the pilot pressure is set to a low pressure, the switching valve is inverted, and when the pilot pressure receiving surface of the spool of the switching valve is at the second switching position that has received the low-pressure hydraulic oil, the small-diameter portion is Opposing the low pressure port, the oil passage control unit opens an oil passage connected to the low pressure port, the piston moves to the second oil chamber side, and the control valve reverses the switching valve. When the position becomes the position, the oil passage control unit closes the oil passage connected to the low pressure port, and reverses the switching position of the switching valve by setting the pilot pressure to a high pressure which is a hydraulic pressure from a hydraulic pressure source. It is characterized in.

As described above, when the switching valve is at the first switching position, the pilot receiving surface of the switching valve is operated by the added pilot mechanism until the piston moves to the predetermined position on the first oil chamber side. Pilot pressure continues to work reliably. On the contrary, when the switching valve is in the second switching position, the pilot pressure receiving surface of the switching valve keeps the low pressure by the added pilot mechanism until the piston reaches the predetermined position on the second oil chamber side. The switching valve is reliably switched, and accordingly, the piston also reliably vibrates at a predetermined stroke.

[0012]

FIG. 1 is a sectional view showing an embodiment of a vibration generator according to the present invention.
Is a body of a vibration generator, in which a piston 2 is reciprocally movable to generate vibration. Reference numeral 3 denotes a large-diameter rod fixed to the first pressure-receiving surface 2a of the piston 2. The large-diameter rod has a tip projecting from the body 1 to the outside. Zu) are connected. Reference numeral 4 denotes a small-diameter rod having a smaller diameter than the large-diameter rod 3, and a base end thereof is fixed to the center of the second pressure receiving surface 2 b of the piston 2. The small diameter rod 4 serves as a spool for a control valve 7 described later.

Reference numeral 5 denotes a first oil chamber defined in the body 1 on the side of the first pressure receiving surface 2a having a pressure receiving area smaller than that of the second pressure receiving surface 2b. The high-pressure oil is constantly supplied to the original hydraulic pressure port 49 connected to the hydraulic pressure source 50 via the passage 15. 6 is a second pressure receiving surface 2b in the body 1.
In the second oil chamber defined on the side, the second oil chamber 6 communicates with a sliding hole 12 of a hydraulic pilot type switching valve 8 to be described later via an oil passage 18.

The spool 9 of the switching valve 8 has a large-diameter portion 9c having small-diameter portions 9a and 9j and a large-diameter portion 9i between them at an intermediate portion and a pressure-receiving surface 9b receiving pilot pressure at the left end in the drawing. A large diameter portion 9d is provided on the right side for communicating or blocking the second oil chamber 6 and the first oil chamber 5. The large diameter portion 9i plays a role of communicating and blocking the second oil chamber 6 and the tank port 21 and a role of blocking and opening the high pressure port 28.

Reference numeral 9e denotes a rod for reducing the pressure receiving area of the right pressure receiving surface 9b of the right large-diameter portion 9d from the pressure receiving surface 9b of the pilot pressure at the left end. The rod 9e is a hole 14 provided in the body 1. The pump port is connected to the oil tank 51 via an oil hole 9g provided in the spool 9 in the axial direction and an oil hole 9h provided in the large-diameter portion 9i in the radial direction. 21 is always in communication.

The oil chamber on the outer periphery of the small diameter portion 9j and the pilot pressure receiving surface 9b communicate with each other through an oil hole 9k provided in the axial direction and an oil hole 9l provided in the small diameter portion 9j in the radial direction. On the inner wall of the sliding hole 12 of the spool 9 of the switching valve 8, a high-pressure port 28 that can communicate with the hydraulic pressure source port 49 via the oil passage 26, and a low-pressure port that can communicate with the tank port 21 via the oil passage 27. 29 are provided. The large-diameter portion 9c at the end of the spool 9 serves to shut off and open the low-pressure port 29.

The spool 4 of the control valve 7 has large diameter portions 4b and 4c on both sides of the small diameter portion 4a. A pilot port 1 communicating with a pilot pressure receiving surface 9 b of the switching valve 8 via an oil passage 20 is provided on an inner wall of the sliding hole 22 of the spool 4.
1 and the position of the spool 4
And a high-pressure port 13 communicating with the hydraulic power source port 49 via the oil passage 16.

The spool 4 has a high-pressure port 2
8. Oil passages 26 and 27 connected to low pressure port 29, respectively
Parts 4d and 4e for communicating and blocking between the large diameter part 4d and 4e
f are provided, and these constitute an oil passage control unit.

The operation of this vibration generator is shown in FIGS.
This will be described below. As shown in FIG. 1, when the position of the spool 9 of the switching valve 8 is at the right end in the drawing, that is, at the first switching position, the pressure receiving chambers 5 and 6 are connected to the oil passage 17, the sliding hole 12, and the oil passage 18. Communicate through. Further, the second oil chamber 6 and the tank port 21 are shut off by the large diameter portion 9i of the spool 9 of the switching valve 8. At this time, since the second pressure receiving surface 2b of the piston 2 is larger than the first pressure receiving surface 2a, the high pressure oil from the hydraulic pressure source 50 causes the piston 2 to move rightward in the drawing to be in a state shown in FIG.

In the state shown in FIG. 2, the small diameter portion 4a of the spool 4 of the control valve 7 has the pilot port 11 and the low pressure port 1
0, and they communicate with each other, so that the pilot pressure acting on the pilot pressure receiving surface 9b of the spool 9 of the switching valve 8 becomes the tank pressure (low pressure), while the right side surface of the large diameter portions 9d, 9i of the spool 9 , The spool 9 moves to the left, and the spool 9 moves to the left in the drawing to reach the second switching position (left end position) as shown in FIG.

When the spool 9 is as shown in FIG. 2, the second oil chamber 6 and the first oil chamber 5 are connected to the large diameter portion 9d of the spool 9.
And at the same time, the second oil chamber 6 communicates with the tank port 21, so that the high pressure oil acting on the first pressure receiving surface 2a causes the piston 2 to move to the left, as shown in FIG.
In the state shown in FIG. 3, the small diameter portion 4a of the spool 4 of the control valve 7 straddles the high pressure port 13 and the pilot port 11 and communicates them, so that high pressure oil is applied to the pilot pressure receiving surface 9b of the spool 9 of the switching valve 8. Because it works, spool 9
Moves rightward, returns to the state of FIG. 1, and the rightward movement of the piston 2 starts. By repeating such an operation, the vibration is performed in an interlocked manner.

Next, the operation of the auxiliary pilot mechanism added according to the present invention will be described. As shown in FIG.
When the pilot pressure receiving surface 9b of the spool 9 is in the first switching position which has received the high-pressure hydraulic oil, the small-diameter portion 9j of the spool 9 of the switching valve 8 faces the high-pressure port 28 and the high-pressure port 28 The high-pressure oil from the hydraulic power source port 49 acts on the small-diameter portion 9j of the switching valve 8 in the oil path 26 leading to the oil passage 26. It acts on the pilot pressure receiving surface 9b on the end surface of the spool through 9l and 9k. This operation of the pilot pressure continues even if the piston 2 moves to the right and the high pressure port 13 and the pilot port 11 are cut off. Therefore, the switching valve 8 is prevented from moving leftward from the rightmost first switching position.

When the piston 2 moves rightward and reaches a predetermined position of the first oil chamber 5 (at or near the stroke end),
Since the switching valve 7 is at the position shown in FIG. 2 and the pilot port 11 communicates with the low pressure port 10, the operating oil acting on the pilot pressure receiving surface 8 b of the switching valve 8 is directed to the oil tank 51 through the oil passages 20 and 19. And high pressure port 2
The oil passage 26 leading to 8 is also blocked by the large diameter portion 4f,
The spool 9 of the switching valve 8 is switched leftward by high-pressure oil acting on the right side of the large diameter portion 9i and the right side of the large diameter portion 9d, and is switched.
The position is the second switching position (left end position) shown in FIG.

Next, as shown in FIG. 2, when the pilot pressure receiving surface 9b of the spool 9 of the switching valve 8 is at the second switching position receiving the low-pressure hydraulic oil, the small-diameter portion 9j is connected to the low-pressure portion 9j. Opposed to port 29 and low pressure port 29
Is connected to the oil passage 27 since the small-diameter portion 4e of the control valve 7 is located, and the pilot pressure receiving surface 9b is connected to the oil holes 9k, 9k.
1, the outer periphery of the small diameter portion 9j, the oil passage 27, the low-pressure port 10, and the oil passage 19 communicate with the tank port 21.
Therefore, as long as the oil passage 27 is not shut off, the spool 9 of the switching valve 8 holds the second switching position.

When the switching valve 8 is at the second switching position, the second oil chamber 6 communicates with the tank port 21 so that the piston 2 moves toward the second oil chamber 6 (leftward). I do. The position where the small diameter portion 4a of the control valve 7 straddles the high pressure port 13 and the pilot port 11, that is, the control valve 7
Is in the control position for reversing the switching valve 8, the large diameter portion 4f blocks the oil passage 27 and the low pressure port 29 as shown in FIG.
Is closed. Therefore, the spool 9 of the switching valve 8 moves to the right and returns to the state of FIG. Such operations are repeated to generate vibration.

As described above, when the switching valve 8 is at the first switching position, the added pilot mechanism (the high pressure port 28 and the high pressure port 28) is used until the piston 2 moves to the predetermined position on the first oil chamber 5 side. Oil path 26, small diameter portion 4 of spool 4 of control valve 7
d, large diameter portion 4f, small diameter portion 9j of spool 9 of switching valve 8,
The oil holes 9k, 9l) ensure that the pilot pressure continues to act on the pilot pressure receiving surface 9b of the switching valve 8, thereby maintaining the first switching position.

On the other hand, when the switching valve 8 is in the second switching position, the additional pilot mechanism (the low pressure port 2) is used until the piston 2 reaches the predetermined position on the second oil chamber 6 side.
9, a small diameter portion 4e of the spool 4 of the control valve 7, a large diameter portion 4f, a small diameter portion 9j of the spool 9 of the switching valve 8, and an oil hole 9.
k, 9l), the pilot pressure receiving surface 9b of the switching valve 8 reliably becomes low pressure, the switching valve 8 reliably maintains the switching position, and accordingly, the piston 2 also reliably vibrates at a predetermined stroke. Therefore, it operates efficiently regardless of the external pressure.

FIG. 4 shows an application example of the vibration generator of the present invention, and shows a debris removal device attached to a tip of a self-propelled debris removal machine for removing gravel contained in cultivated land. In this rubble removal apparatus, a plurality of rubble rotation rods 61 are arranged on a frame 60 attached to the front end of a self-propelled rubble machine main body (not shown) so as to be able to be raised and lowered. In the direction (upward direction), and by the self-propelled operation of the degraving machine, scoop up the earth and sand while digging the hoe part 63 at the end of the frame into the ground, and send it backward by the rod 61 to protrude from the rod. The earth and sand is dropped on the ground from between the rods 61a, and the gravel is sent backward.

In such a degraving device, the frame 6
A hoe portion 63 is rotatably provided around a pivot portion 64 provided at the front end of the frame 60, and a rod 66 and a vibration generator 67 according to the present invention are provided between the hoe portion 63 and a bracket 65 provided on the lower surface of the frame 60. Are connected in series via rubber 68 and interposed. By vibrating the hoe part 63 back and forth about the pivotal attachment part 64, the vibration generating device 67 can efficiently dig the hoe part 63 into the ground. The vibration generating apparatus of the present invention can efficiently apply vibration even when a large load is carried out in each of the operations described above.

[0030]

According to the present invention, the self-holding means for holding the switching position of the switching valve until the piston connected to the load reaches the limit positions at both ends of the reciprocation is provided, so that the piston has a large resistance. Even when an external force such as a load is received, the switching valve is reliably switched to a predetermined switching position by the self-holding means, thereby preventing a malfunction of the piston and vibrating reliably with a predetermined vibration stroke. Therefore, even when a large external force is applied, vibration can be efficiently applied to the load.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a vibration generator according to the present invention.

FIG. 2 is a sectional view showing another process of the vibration operation of the embodiment of FIG. 1;

FIG. 3 is a sectional view showing still another process of the vibration operation of the embodiment of FIG. 1;

FIG. 4 is a side view showing a debris removal apparatus as an application example of the present invention.

[Explanation of symbols]

1: body, 2: piston, 2a: first pressure receiving surface, 2
b: second pressure receiving surface, 3: large diameter rod, 4: small diameter rod (spool), 4a, 4d, 4e: small diameter portion, 4b, 4
c, 4f: large diameter portion, 5: first oil chamber, 6: second oil chamber,
7: control valve, 8: switching valve, 9: spool, 9a, 9j:
Small diameter part, 9b: Pilot pressure receiving surface, 9c, 9d, 9i:
Large diameter part, 9g, 9h, 9k, 9l: Oil hole, 10: Low pressure port, 11: Pilot port, 12: Sliding hole, 13:
High pressure port, 14: hole, 15-20: oil passage, 21: tank port, 26, 27: oil passage, 28: high pressure port, 2
9: Low pressure port, 49: Hydraulic power source port, 50: Hydraulic power source,
51: oil tank, 60: frame, 61: debris rod, 62: motor, 63: hoe, 64: pivot, 65:
Bracket, 66: rod, 67: vibration generator, 6
8: Rubber

Claims (2)

[Claims] A piston having a first pressure receiving surface having a small pressure receiving area and a second pressure receiving surface having a pressure receiving area larger than the pressure receiving surface; A first oil chamber defined on the first pressure receiving surface side of the piston and connected to a hydraulic pressure source; and a first oil chamber defined on the second pressure receiving surface side of the piston and defined in the body. The second oil chamber is connected to the first oil chamber in accordance with the pilot pressure of the hydraulic oil supplied to and discharged from the hydraulic pilot section, and the piston is moved to the first oil chamber. Hydraulic pressure selectively switched between a first switching position for moving to the oil chamber side and a second switching position for moving the piston to the second oil chamber by connecting the second oil chamber to a tank. A pilot-operated switching valve, operated in conjunction with the piston, wherein the piston is the first When the piston moves to the oil chamber side and reaches a predetermined position, the pilot pressure of the hydraulic pilot type switching valve is set to a low pressure, the switching valve is switched to the second switching position, and the piston moves to the second oil chamber side. A control valve for switching the switching valve to a first switching position by using hydraulic pressure from a hydraulic source as a pilot pressure of the hydraulic pilot switching valve when the control valve reaches a predetermined position. Is provided with self-holding means for holding the first switching position or the second switching position, which is the current position of the switching valve, when the switching valve is at the intermediate position where the pilot pressure is not supplied to the pilot portion of the switching valve. A vibration generator characterized by the above-mentioned. 2. The vibration generating device according to claim 1, wherein said self-holding means is provided on an inner wall of a sliding hole of a spool of said switching valve, and has a high-pressure port that can communicate with a hydraulic pressure source and a low-pressure port that can communicate with a tank. A port, a large-diameter portion provided at an intermediate portion of a spool of the switching valve, and a large-diameter portion provided between the large-diameter portion and a large-diameter portion having a pilot pressure receiving surface at an end surface of the spool, and an oil provided on the spool. A small-diameter portion connected to the pilot pressure receiving surface by a hole,
An oil passage control unit is provided on a spool of the control valve and communicates and shuts off an oil passage communicating with the high pressure port and an oil passage communicating with the low pressure port, respectively, and a pilot pressure receiving surface of the spool of the switching valve has a high pressure. When in the first switching position receiving the hydraulic oil, the small-diameter portion of the spool of the switching valve faces the high-pressure port, and the oil-path control unit opens an oil path connected to the high-pressure port, When the piston moves and the control valve comes to the control position for inverting the switching valve, the oil passage control unit closes the oil passage connected to the high pressure port and sets the pilot pressure to low to invert the switching valve. When the pilot pressure receiving surface of the spool of the switching valve is at the second switching position receiving the low-pressure hydraulic oil, the small-diameter portion is opposed to the low-pressure port and the oil passage control is performed. Wherein opening the oil passage leading to the low pressure port, the piston moves to the second oil chamber side, if the control position of the control valve to reverse the switching valve,
The vibration generating device is characterized in that the oil passage control section closes an oil passage connected to the low pressure port and reverses a switching position of the switching valve by setting the pilot pressure to a high pressure which is a hydraulic pressure from a hydraulic pressure source.