JP2009297846A - Impact type fastening tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of tool performance degradation due to leakage of oil filled in a hydraulic pulse generation device caused by degradation due to tightening work in the hydraulic pulse generation device. <P>SOLUTION: In the hydraulic pulse generation device (P), a main shaft (7) is fitted and inserted in a hole (30) formed at a liner lower lid (3) to rotate freely, oil is filled in a liner chamber (20) closed by the liner lower lid (3) and a liner upper lid (4), and a seal chamber (8) is formed for housing a seal material (80) between a configurative surface of the hole (30) of the liner lower lid (3) and the outer circumference surface of the main shaft (7). The impact type fastening tool includes the hydraulic pulse generation device (P) where an open and close valve (V) consisting of a valve body (V1) and an energization means (V2) for energizing the valve body (V1) at a closed position is provided at an oil passage (31) for connecting the inside of the seal chamber (8) with the inside of the liner chamber (20). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to an impact type tightening tool provided with a hydraulic pulse generator.

  2. Description of the Related Art Conventionally, impact-type tightening tools, which are tools that perform tightening by generating a pulse by a hydraulic pulse generator filled with oil in a liner (Patent Documents 1 and 2).

  In conventional impact-type tightening tools, when the seating surface of the tightening bolt is seated during bolt tightening, the main shaft is loaded and the main shaft, blades and springs are almost stopped, and the liner, liner case, under the liner The lid and the liner upper lid continue to rotate, and one hydraulic pulse is generated per rotation in accordance with the rotation of the liner and the like in the rotating state. At the time of generating the hydraulic pulse, the hydraulic pulse generator has an inner circumference of the liner. The contact between the pair of projecting seal surfaces formed on the surface and the pair of projecting seal surfaces formed on the outer peripheral surface of the shaft, and the contact between the pair of projecting seal surfaces formed on the inner peripheral surface of the liner and the blade It is divided into a high pressure chamber and two low pressure chambers. The main shaft rotates to tighten the bolt due to the pressure difference between the high pressure chamber and the low pressure chamber.

However, as shown in FIG. 7, when a hydraulic pulse is generated, the oil in the high-pressure chamber passes through a clearance (about 0.01 mm) between the main shaft (7) and the liner lower lid (3) and is an O-ring (80 ) Enters the seal chamber (8) containing the oil pressure, and the oil pressure is accumulated in the seal chamber (8) every time a hydraulic pulse is generated. Accumulation of this oil pressure becomes a factor of oil leakage, which is a problem because it reduces the ability of the tool.
JP-A-4-360776 JP-A-62-246481

  Therefore, an object of the present invention is to provide an impact-type tightening tool including a hydraulic pulse generator that suppresses a reduction in the capability of the tool by preventing leakage of oil filled in the hydraulic pulse generator as much as possible. Is to provide.

  According to the present invention, the main shaft (7) is rotatably inserted in the hole (30) formed in the liner lower lid (3), and is closed by the liner lower lid (3) and the liner upper lid (4). In order to fill the liner chamber (20) with oil and to accommodate the sealing material (80) between the constituent surface of the hole (30) of the liner lower lid (3) and the outer peripheral surface of the main shaft (7). In the hydraulic pulse generator (P) having the seal chamber (8) formed in the oil passage (31), the oil passage (31) connecting the inside of the seal chamber (8) and the liner chamber (20), and the oil passage (31) An impact-type tightening tool provided with a hydraulic pulse generator (P), characterized in that an opening / closing means (V) is provided.

  A liner chamber in which a main shaft (7) is rotatably fitted in a hole (30) formed in the liner lower lid (3) and is closed by the liner lower lid (3) and the liner upper lid (4). (20) The oil is filled into the oil, and the oil passes through a clearance that is a gap between the outer surface of the main shaft (7) and the surface (inner surface) of the hole (30) of the liner lower lid (3). In the hydraulic pulse generator (P) having a seal chamber (8) formed to accommodate the seal material (80) for preventing the outflow, the inside of the seal chamber (8) and the liner chamber (20) are provided. An impact-type tightening tool comprising an oil passage (31) communicating and a hydraulic pulse generator (P) provided with an opening / closing means (V) in the oil passage (31).

  Further, a liner lower lid (3) having a hole (30) into which the main shaft (7) is rotatably inserted, and a liner chamber (20) closed by the liner lower lid (3) and the liner upper lid (4). Oil is filled inside, and a sealing material (80) is provided between the outer peripheral surface of the main shaft (7) and the surface (inner peripheral surface) of the hole (30) of the liner lower lid (3) facing the main shaft (7). In the hydraulic pulse generator (P) having a seal chamber (8) formed as an annular groove on the inner peripheral surface of the liner lower lid (3), the inside of the seal chamber (8) and the liner chamber (20 And an oil passage (31) communicating with each other and an opening / closing means (V) provided in the oil passage (31). .

  Further, according to the present invention, the main shaft (7) is rotatably inserted into the hole (30) formed in the liner lower lid (3) and is closed by the liner lower lid (3) and the liner upper lid (4). The sealed liner chamber (20) is filled with oil, and a sealing material (80) is accommodated between the component surface of the hole (30) of the liner lower lid (3) and the outer peripheral surface of the main shaft (7). In a hydraulic pulse generator (P) having a seal chamber (8) formed for the purpose, an opening / closing means (V) is provided in an oil passage (31) connecting the seal chamber (8) and the liner chamber (20). The hydraulic pulse generator (P) is characterized in that the opening / closing means (V) includes a main body (V1) and an urging means (V2) for urging the main body (V1) to a closed position. It is an impact type tightening tool provided.

  A liner chamber in which a main shaft (7) is rotatably fitted in a hole (30) formed in the liner lower lid (3) and is closed by the liner lower lid (3) and the liner upper lid (4). (20) Filled with oil and formed to accommodate the sealing material (80) between the surface of the hole (30) of the liner lower lid (3) and the outer peripheral surface of the main shaft (7). In the hydraulic pulse generator (P) having a sealed chamber (8), an open / close valve (V) is provided in an oil passage (31) connecting the inside of the sealed chamber (8) and the liner chamber (20). The valve (V) includes a valve body (V1) and an urging means (V2) for urging the valve body (V1) to a closed position. It is a type tightening tool.

  A liner chamber in which a main shaft (7) is rotatably fitted in a hole (30) formed in the liner lower lid (3) and is closed by the liner lower lid (3) and the liner upper lid (4). (20) Filled with oil and formed to accommodate the sealing material (80) between the surface of the hole (30) of the liner lower lid (3) and the outer peripheral surface of the main shaft (7). In the hydraulic pulse generator (P) having the sealed chamber (8), an open / close valve (V) is provided in an oil passage (31) connecting the seal chamber (8) and the liner chamber (20). V) includes a valve body (V1) and urging means (V2) for urging the valve body (V1) to a closed position. The valve body (V1) is moved by oil pressure from the seal chamber (8). Hydraulic pulse generator characterized by being moved to an open position (P A impact fastening tool comprising a.

  The hydraulic pulse generator of the present invention can suppress a reduction in the capability of the tool itself by suppressing oil leakage from the liner.

  Hereinafter, an embodiment as the best mode for carrying out the hydraulic pulse generator of the present invention will be described in detail.

  FIG. 1 is a partial cross-sectional view of a two-blade impulse wrench R which is an impact-type tightening tool having a hydraulic pulse generator P of the present invention. FIG. 2 is a cross-sectional view of the hydraulic pulse generator P of the present invention. FIG. 4 is a cross-sectional view of the hydraulic pulse generator P taken along the line A-A in FIG. 2 when the impulse wrench R is in use, showing a one-turn movement in the first to fifth stages, and FIG. FIG. 5 shows an enlarged sectional view of the second stage in the hydraulic pulse generator P. FIG.

  As shown in FIG. 1, the two-blade type impulse wrench R is rotated by a rotational drive source, and a liner 2 that seals oil inside, a main shaft 7 that is rotatably inserted in the liner 2, and the main shaft The outer surface of the shaft 7 has a blade 5 that slides on the inner surface of the liner 2 as the liner 2 rotates. The liner 2 rotates and the liner 2 rotates. 2 generates a hydraulic pulse in the main shaft 7 when the seal portion formed on the inner peripheral surface 2 matches the seal portion formed on the outer peripheral surface of the main shaft 7 and the outer end surface of the blade 5. Impulse wrench R with device P.

  First, the hydraulic pulse generator P in the 2-blade type impulse wrench R will be described.

  As shown in FIGS. 1 and 2, the hydraulic pulse generator P is provided with a liner 2 in a liner case 1, and a main shaft 7 is fitted into the liner 2 to rotate the liner 2 with respect to the main shaft 7. The liner 2 is filled with oil for generating torque and sealed by a liner lower lid 3 and a liner upper lid 4 attached to both ends of the liner 2.

  As shown in FIG. 2, a hole 30 for inserting the main shaft 7 is formed in the liner lower lid 3, and an annular shape formed between the wall surface of the hole 30 and the outer peripheral surface of the main shaft 7. An O-ring 80 for ensuring airtightness (fluid tightness) between these is accommodated in the seal chamber 8.

  The liner case 1 and the liner 2 are coupled to each other, and are rotated integrally by the rotation of the motor M.

  As shown in FIG. 4, a liner chamber 20 having an elliptical cross section is formed inside the liner 2, and the blade 5 is inserted into two opposing groove portions 70, 70 of the main shaft 7 via a spring 6. 5 is in contact with the inner surface of the liner 2 having an elliptical cross section so as to be able to appear and retract. On the outer peripheral surface of the main shaft 7 between the two blades 5 and 5, second seal surfaces 71 and 72 formed on two protrusions are provided.

  As shown in FIG. 4, the inner peripheral surface of the liner 2 has first seal surfaces 21, 22, 23, 24 that are raised in a mountain shape at both ends of a short axis having an elliptical cross section and both ends of the long axis. It is provided. When the liner 2 makes one rotation with respect to the main shaft 7, as shown in FIGS. 3 (1), (2), FIG. 4 and FIG. The seal surface 71, the first seal surface 22 and the second seal surface 72, the first seal surface 23 and the outer end surface of one blade 5 are matched, and the first seal surface 24 and the outer end surface of the other blade 5 are matched. (They match to maintain an airtight state in the entire axial direction of the main shaft 7), so that the liner chamber 20 is hermetically partitioned into four chambers, two high-pressure chambers H and two low-pressure chambers L. .

  Since the hydraulic pulse generator P is configured as described above, a two-blade impulse wrench R using the hydraulic pulse generator P functions as follows.

  When compressed air is supplied to the motor M by operating the throttle lever SL, the motor M rotates at a high speed, and the liner 2 also rotates accordingly.

  As the liner 2 rotates, the liner chamber 20 changes at 90 ° intervals as shown in FIGS. 3 (1) (2)-(3)-(4)-(5) while the liner 2 rotates once. To do.

  (1) and (2) in FIG. 3 show a state where a striking force is generated on the main shaft 7 by a hydraulic pulse.

  3 (1) and the enlarged state of FIG. 4, the first seal surface 21 and the second seal surface 71 are the same, the first seal surface 22 and the second seal surface 72 are the same as the first seal surface 23 and the other. The outer end surface of the blade 5 matches the first seal surface 24 and the outer end surface of the other blade 5 (matches so as to maintain an airtight state in the entire axial direction of the main shaft 7). Are hermetically partitioned into four chambers, two high-pressure chambers H and two low-pressure chambers L.

  As shown in (2) of FIG. 3 and FIG. 5 which is an enlarged view of this, when the liner 2 is further rotated by the rotation of the motor M, the volume of the high-pressure chamber H is reduced, so that the oil is compressed and the high pressure is instantaneously increased. This high pressure pushes the blade 5 toward the low pressure chamber L side. The main shaft 7 momentarily acts on the main shaft 7 via the upper and lower blades 5 and 5 to generate a strong torque.

  (3) in FIG. 3 shows a state in which the liner 2 has rotated 90 ° after torque is generated on the main shaft 7.

In the liner chamber 20, the high-pressure chamber H and the low-pressure chamber L formed with the upper and lower blades 5, 5 are connected to each other and no torque is generated, and the liner 2 further rotates as the motor M rotates.
(4) in FIG. 3 shows a state in which the ball is further rotated by 180 ° from the state of FIG.

The first seal surface 21 and the second seal surface 72 do not match, and the first seal surface 22 and the second seal surface 71 only match at a very small part. Therefore, no sealing is performed between these sealing surfaces, and no pressure change occurs, so no torque is generated. The liner 2 rotates as it is.
FIG. 3 (5) shows a state in which it is further rotated by 90 ° from the state of (4) in FIG.

  This state is substantially the same as the state (3) in FIG. 3, and no torque is generated. Further rotation returns to the state of (1) in FIG. 3, the first seal surface 21 and the second seal surface 71, the first seal surface 22 and the second seal surface 72, the first seal surface 23 and the one blade 5. The outer end surfaces of the first seal surface 24 and the outer end surface of the other blade 5 coincide with each other, and a striking force is generated again.

  The above shows the configuration and operation of a known impact type tool. Next, the characteristic configuration of the present invention will be described. In the present invention, an oil passage 31 that connects the inside of the seal chamber 8 and the liner chamber 20 is provided, and an on-off valve V is provided in the oil passage 31. The on-off valve V includes a valve body V1 such as a steel ball, and an urging means V2 such as a spring that urges the valve body V1 to the closed position.

  The seal chamber 8 is for accommodating a sealing material 80 such as an O-ring, and is a space formed between the constituent surface of the hole 30 of the liner lower lid 3 and the outer peripheral surface of the main shaft 7. The constituent surface of the hole 30 is the inner constituent surface of the liner lower lid 3 that faces the outer peripheral surface of the main shaft 7 as shown in FIG. A part of the intermediate portion of the constituent surfaces facing the main shaft 7 constitutes the seal chamber 8, and the rear portion of the other portion of the liner chamber 20 side of the seal chamber 8 with the outer peripheral surface of the main shaft 7. An inner clearance C is formed between them (the clearance on the main shaft side of the liner chamber is the outer clearance).

  As shown in FIG. 2 and the like, the main shaft 7 has a large-diameter portion 73 at a substantially central portion in the axial direction. A clearance C is formed.

  The hole 30 of the liner lower lid 3 has a large-diameter portion whose inner diameter is relatively larger than other portions, and this large-diameter portion constitutes the seal chamber 8. As shown in FIG. 2, the inner diameter of the hole 30 of the liner lower lid 3 is the same except for the portion constituting the seal chamber 8 containing the sealing material 80, and the portion constituting the seal chamber 8 is the same as that of the liner lower lid 3. It has a relatively larger diameter than the inner diameter of the other part. A gap between the inner peripheral surface of the liner lower lid 3 and the outer peripheral surface of the large-diameter portion 73 of the main shaft 7 in a portion excluding the portion constituting the seal chamber 8 and closer to the liner chamber 20 than the seal chamber 8. Becomes clearance C.

  The oil passage 31 is formed in the liner lower lid 3 and has one end communicating with the seal chamber 8 and opening, and the other end communicating with the liner chamber 20 and opening. The liner lower lid 3 includes an outer liner lower lid 32 disposed on the front end side of the main shaft 7 and an inner liner lower lid 33 disposed relatively on the rear end side of the main shaft 7. 32, from a small-diameter portion (hole diameter) on the tip side facing the main shaft 7 via a clearance C, and a large-diameter portion (hole diameter) facing the main shaft 7 by forming a seal chamber 8 at a predetermined interval. Thus, the inner liner lower lid 33 is fixed with its front end protrusion fitted into the large diameter portion of the outer liner lower lid 32.

  Tubular oil passages are formed in the outer liner lower lid 32 and the inner liner lower lid 33, respectively, and an upstream oil passage is connected to the outer liner lower lid 32 and a downstream oil passage is connected to the inner liner lower lid 33 to the upstream oil passage. Is formed.

  The outlet of the upstream side oil passage of the outer liner lower lid 32 is closed by the valve body V1, and has a cross-sectional taper shape on which the valve body V1 can be seated in order to maintain a good state in which the valve body V1 does not move. A recess is formed. Further, the inner liner lower lid 33 is formed with a step portion that comes into contact with one end of a spring V2 that biases the valve body V1 in the direction of the outer liner lower lid 32, and the spring V2 is provided between the step portion and the valve body V1. Is placed. One end of the spring V2 is in contact with the stepped portion, and the other end is in contact with the liner surface of the valve body V1.

  The on-off valve V holds the valve body V1 in the closed position by the pressing force of the spring which is the urging means V2 and the oil pressure in the liner chamber 20, and also opens the valve body V1 by the oil pressure from the seal chamber 8. To move on. That is, when the oil pressure pulse is generated and the oil that has entered the seal chamber 8 through the clearance C between the hole 30 of the liner upper lid 3 and the main shaft 7 is accumulated in the seal chamber 8, the pressure of the high-pressure oil causes The valve body V1 moves from the closed position to the open position, and the oil that has entered the seal chamber 8 flows out into the liner chamber 20 to reduce the pressure in the seal chamber 8.

  FIG. 6 shows P3 showing the pressure change in the seal chamber 8 when the oil passage 31 and the open / close valve V are not provided, and the pressure change in the present embodiment where the oil passage 31 and the open / close valve V are provided. P1 is schematically illustrated. The pressure (P2) in the liner chamber 20 of the hydraulic pulse generator P tends to gradually increase while generating a very high pressure at the time of the generation of the hydraulic pulse and then repeating the behavior in which the pressure rapidly decreases a plurality of times. The pressure (P2) in the liner chamber 20 decreases and the pressing force that presses the valve body V1 in the closing direction becomes smaller. On the other hand, the oil pressure (P1) on the seal chamber 8 side, that is, the clearance C When the pressure of oil in the seal chamber 8 that has entered the seal chamber 8 becomes relatively large, the valve body V1 moves from the closed position to the open position, and the oil that has entered the seal chamber 8 passes through the oil passage 31. It flows out into the liner chamber 20 and reduces the pressure in the seal chamber 8. When the pressure in the seal chamber 8 decreases, the on-off valve V returns to the closed position, and again moves to the open position due to the pressure of the oil flowing into the seal chamber 8 due to the hydraulic pulse generated again. The action returns to the closed position and repeats this.

  Here, as in the prior art shown in FIG. 7, when the oil passage 31 and the on-off valve V are not provided, the oil flowing into the seal chamber 8 from the clearance C has a reduced pressure in the liner chamber 20. At this time, it may be possible to flow out of the clearance C into the liner chamber and return to the liner chamber. However, the clearance C is usually only about 0.01 mm without being subjected to extremely high pressure due to the hydraulic pulse as in the case of intrusion. The oil in the seal chamber 8 hardly returns to the liner chamber 20 via the oil pressure, so that the oil pressure is successively accumulated in the seal chamber 8 every time a hydraulic pulse is generated (P3 in FIG. 6). This will lead to leakage. On the other hand, in the present invention, the pressure acting in the direction of moving the valve body V1 to the open position prevents the pressure in the seal chamber 8 from being accumulated one after another. When the pressure becomes larger than the pressure acting in the moving direction, the valve body moves to the open position against the pressure acting to hold the valve body V1 in the closed position, and enters the seal chamber 8. The oil thus returned is returned to the liner chamber 20 through the oil passage 31. That is, when the pressure of the oil in the seal chamber 8 acting in the direction of moving the valve body V1 to the open position becomes larger than the combined pressure of the pressure by the urging means V2 and the oil pressure in the liner chamber 20, Since V1 moves to the open position, the oil that has entered the seal chamber 8 flows out to the liner chamber 20 side through the oil passage 31. When the oil in the seal chamber 8 flows into the liner chamber 20, the pressure in the seal chamber 8 decreases. As a result, the oil pressure is accumulated and increased one after another in the seal chamber 8 every time a hydraulic pulse is generated. Prevent oil leakage.

  Further, the on / off valve is a reverse support valve that prevents oil from flowing in, that is, a reverse support valve that makes the oil flow unidirectionally flow from the seal chamber 8 to the liner chamber 20. Thus, the oil is prevented from flowing into the seal chamber 8, so that the accumulation of oil pressure in the seal chamber 8 is effectively prevented.

  In FIG. 6, the pressure in the liner chamber acting in the direction of closing the valve body V1 is omitted from the urging means for convenience of explanation.

  As described above, when the pressure changes from (1) in FIG. 3 to (2) in FIG. 3, the pressure in the high-pressure chamber H becomes maximum, and the wall surface of the hole 30 of the liner lower lid 3 and the outer surface of the main shaft 7 The oil in the high-pressure chamber H enters the seal chamber 8 from the clearance C formed between the two, but in the hydraulic pulse generator P, the valve main body V1 is moved to the open position by entering from the high-pressure chamber H. When the pressure of the acting oil becomes larger than the pressure of the oil pressure in the liner chamber 20 and the pressure by the biasing means V2, the valve body V1 moves to the open position, so that it enters the seal chamber 8. The oil thus discharged flows out to the liner chamber 20 side through the oil passage 31. As a result, the accumulation of oil is prevented, oil leakage can be avoided, and there is an excellent effect that the early capability deterioration of the tool itself is not caused.

  In addition, as shown in FIG. 8, you may provide the recessed part G in the part which forms clearance among the outer peripheral surfaces of the main shaft 7. FIG. For example, a recess G that is a groove having a relatively smaller diameter than the diameter of the large-diameter portion 73 of the main shaft 7 may be formed. Specifically, the recess G may be formed on the outer peripheral surface of the main shaft 7 and You may form the annular groove opened to the direction. In such a case, the oil that enters from the liner chamber 20 through the clearance C when the hydraulic pulse is generated flows into the recess G that is relatively larger than the clearance C and expands. After that, it flows into the seal chamber 8. Therefore, as compared with the case where the concave portion G is not provided, the oil pressure applied to the O-ring 80 accommodated in the seal chamber 8 is reduced, and wear of the O-ring 80 is prevented as much as possible and oil leakage is prevented. Can be prevented.

  The recess G is provided in the outer peripheral surface region of the main shaft 7 in the axial direction from the liner chamber side opening C1 which is one end of the clearance C to the seal chamber side opening C2 which is the other end. It can also be provided in the inner peripheral surface area of the liner lower lid 3 between the chamber side opening C1 and the seal chamber side opening C2.

  In addition, although the said Example is a 2 blade type impulse wrench, it is not limited to this, It can be set as a 1 blade type and a 3 blade type.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional view of a two-blade impulse wrench having a hydraulic pulse generator according to Embodiment 1 of the present invention. Sectional drawing of the said hydraulic pulse generator. FIG. 6 is a cross-sectional view taken along the line AA of FIG. 2 of the hydraulic pulse generator in the use state of the impulse wrench, showing a one-turn movement in first to fifth stages. The expanded sectional view of the 1st step in the said hydraulic pulse generator. The expanded sectional view of the 2nd step in the said hydraulic pulse generator. Diagram showing pressure change Sectional drawing of the conventional hydraulic pulse generator. The figure which shows another Example.

Explanation of symbols

1 liner case 2 liner 3 liner lower lid 4 liner upper lid 5 blade 6 spring 7 main shaft 8 seal chamber 20 liner chamber 21 first seal surface 22 first seal surface 23 first seal surface 24 first seal surface 30 hole 31 oil passage 70 groove 71 second seal surface 72 second seal surface 80 O-ring V on-off valve G recess

Claims (3)

A main chamber (7) is rotatably inserted into a hole (30) formed in the liner lower lid (3), and a liner chamber (20) closed by the liner lower lid (3) and the liner upper lid (4). ) Is filled with oil and is formed to accommodate the sealing material (80) between the constituent surface of the hole (30) of the liner lower lid (3) and the outer peripheral surface of the main shaft (7). In the hydraulic pulse generator (P) having a seal chamber (8), an oil passage (31) connecting the inside of the seal chamber (8) and the liner chamber (20), and an opening / closing means (V An impact-type tightening tool provided with a hydraulic pulse generator (P). A main chamber (7) is rotatably inserted into a hole (30) formed in the liner lower lid (3), and a liner chamber (20) closed by the liner lower lid (3) and the liner upper lid (4). ) Is filled with oil and is formed to accommodate the sealing material (80) between the constituent surface of the hole (30) of the liner lower lid (3) and the outer peripheral surface of the main shaft (7). In the hydraulic pulse generator (P) having a seal chamber (8), an open / close means (V) is provided in an oil passage (31) connecting the seal chamber (8) and the liner chamber (20), and the open / close means ( V) comprises a main body (V1) and an urging means (V2) for urging the main body (V1) to a closed position. . A main chamber (7) is rotatably inserted into a hole (30) formed in the liner lower lid (3), and a liner chamber (20) closed by the liner lower lid (3) and the liner upper lid (4). ) Is filled with oil and is formed to accommodate the sealing material (80) between the constituent surface of the hole (30) of the liner lower lid (3) and the outer peripheral surface of the main shaft (7). In the hydraulic pulse generator (P) having a seal chamber (8), an open / close valve (V) is provided in an oil passage (31) connecting the seal chamber (8) and the liner chamber (20), and the open / close valve (V) Consists of a valve body (V1) and urging means (V2) for urging the valve body (V1) to the closed position, and the valve body (V1) is opened by oil pressure from the seal chamber (8). Hydraulic pulse generator characterized by being an on-off valve (V) Impact fastening tool comprises a).

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