JP2009297847A - 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 a liner upper lid 4 facing a shaft direction of the main shaft 7 to the liner lower lid 3, and a seal chamber 8 for preventing oil from flowing out through a clearance C that is a gap between an outer circumference surface of the main shaft 7 and an inner circumference surface of the hole 30 of the liner lower lid 3 facing the outer circumference surface and housing a seal material 80 is provided. The impact type fastening tool includes the hydraulic pulse generation device P where a recess part G is formed at the outer circumference surface of the main shaft 7 for forming from a liner chamber 20 side opening C1 that is one end of the clearance C to a seal chamber side opening C2. <P>COPYRIGHT: (C)2010,JPO&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. 12, when a hydraulic pulse is generated, the oil in the high-pressure chamber contains an O-ring (80) that is a sealing material through the clearance between the main shaft (7) and the liner lower lid (3). Since the oil enters the seal chamber (8), the pressing force of the oil increases the pressure contact force between the inner periphery of the O-ring (80) and the main shaft (7). As a result, the O-ring (80) is worn. Will do. This wear of the O-ring is a cause of oil leakage, which is a problem because it reduces the ability of the tool.
JP-A-4-360776 JP-A-62-246481

  Accordingly, an object of the present invention is to provide an impact-type tightening tool equipped with a hydraulic pulse generator that prevents 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.

  In the present invention, a main shaft (7) is rotatably fitted in a hole (30) formed in a liner lower lid (3), and the shaft of the main shaft (7) is inserted into the liner lower lid (3). The liner chamber (20) closed with the liner upper lid (4) facing in the direction is filled with oil, and the inner circumference of the hole (30) of the liner lower lid (3) facing the outer circumferential surface of the main shaft (7) In a hydraulic pulse generator (P) having a seal chamber (8) that contains a seal material (80) that prevents oil from flowing out through a clearance (C) that is a gap with the surface, the outer periphery of the main shaft (7) A seal chamber (20) on the side of the liner chamber (20), which is one end of a clearance (C) formed by the inner peripheral surface of the hole (30) of the liner lower lid (3) facing the surface, and a seal chamber ( 8) Main shaft (7) of side opening (C2) Impact type equipped with a hydraulic pulse generator (P) characterized in that a recess (G) opened in the direction of the inner peripheral surface of the liner lower lid (3) is formed on the outer peripheral surface of the main shaft (7) between the directions. It is a tightening tool.

  Further, according to the present invention, the main shaft (7) is rotatably fitted in the hole (30) formed in the liner lower lid (3), and the main shaft (7) is inserted into the liner lower lid (3). The liner chamber (20) closed by the liner upper lid (4) facing in the axial direction is filled with oil, and the hole (30) of the liner lower lid (3) facing the outer peripheral surface of the main shaft (7) is filled. In a hydraulic pulse generator (P) having a seal chamber (8) containing a seal material (80) for preventing oil from flowing out through a clearance (C) which is a gap with an inner peripheral surface, a main shaft (7) The liner chamber (20) side opening (C1), which is one end of the clearance (C) constituted by the outer peripheral surface of the liner and the inner peripheral surface of the hole (30) of the liner lower lid (3) facing the seal, communicates with this. Main shaft of chamber (8) side opening (C2) 7) A hydraulic pulse generator (P) characterized in that a recess (G) opened in the outer peripheral surface direction of the main shaft (7) is formed on the inner peripheral surface of the liner lower lid (3) between the axial directions. It is an impact type tightening tool provided.

  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.

  Example 1 is shown in FIGS.

  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. 3 to 5 are common to the embodiments.

  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 seal chamber 8 is formed by forming an annular groove on the inner peripheral surface of the liner lower lid 3, and accommodates an O-ring fitted in the annular groove.

  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. A powerful torque is generated by momentarily acting on the main shaft 7 via the upper and lower blades 5 and 5.
(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, the main shaft 7 is rotatably inserted into a hole 30 formed in the liner lower lid 3, and is closed with the liner upper lid 4 facing the liner lower lid 3 in the axial direction of the main shaft 7. The liner chamber 20 is filled with oil, and a sealing material 80 that prevents the oil from flowing out through a clearance C that is a gap between the outer peripheral surface of the main shaft 7 and the inner peripheral surface of the hole 30 of the liner lower lid 3 is accommodated. In the hydraulic pulse generator P having the seal chamber 8, the recess G is formed on the outer peripheral surface of the main shaft 7 between the liner chamber side opening C1 which is one end of the clearance C and the seal chamber side opening C2. It is an impact type tightening tool provided with the hydraulic pulse generator P which is characterized.

  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, and between the outer peripheral surface of the large-diameter portion 73 and the inner peripheral surface of the hole 30 of the liner lower lid 3. The inner clearance C (the outer shaft of the main shaft 7 and the main shaft 7 more than the seal chamber 8 out of the clearance C formed by the outer surface of the main shaft 7 and the inner surface of the hole 30 facing each other). 7 is the outer clearance, and the liner chamber 20 side of the seal chamber 8 is the inner clearance.). The outer peripheral surface of the main shaft 7, where the outer peripheral surface of the main shaft 7 and the inner peripheral surface of the hole 30 face each other, and at a location closer to the liner chamber 20 than the seal chamber side opening C 2 of the seal chamber 8. Is formed with a recess G which is an annular groove recessed in the axial center direction of the main shaft 7. A concave portion G having a relatively smaller diameter than the diameter of the large diameter portion 73 is formed in the large diameter portion 73 of the main shaft 7. The recess G in this embodiment is an annular groove formed on the outer peripheral surface of the main shaft 7 and opened outward. In addition, the groove | channel which comprises the recessed part G does not necessarily need to be cyclic | annular, The part (for example, arc shape) may be sufficient.

  The inner diameter of the liner lower lid 3 has a large diameter portion that is relatively larger in inner diameter than the 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 the inner clearance C.

According to the present embodiment, the oil that enters through the clearance C from the liner chamber 20 when the hydraulic pulse is generated flows into the recess G that is relatively larger than the clearance C and expands. Thereafter, 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, so that 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 between the liner chamber side opening C1 which is one end of the clearance C and the seal chamber side opening C2, but the liner C side opening C1 of the clearance C is provided. To the inner circumferential surface of the liner lower lid 3 in the axial direction from the seal chamber side opening C2.

  As for clearance C, as shown in FIG. 2, the distance between the surfaces in the radial direction at the portion where the outer peripheral surface of the main shaft 7 and the inner peripheral surface of the liner lower lid 3 substantially contact each other can be regarded as the clearance C. For example, the recess G is a recess G having a radial distance (depth) larger than the inter-surface distance. In addition, regarding the clearance C, if the difference in diameter between the main shaft 7 and the liner lower lid 3 is substantially in contact with each other is referred to as clearance C, the recess G is larger than the diameter of the main shaft 7 in the region constituting the clearance C. Is a recess G having a relatively small diameter.

  A second embodiment is shown in FIGS.

  Also in this embodiment, the main shaft 7 is rotatably fitted in the hole 30 formed in the liner lower lid 3 and is closed by the liner upper lid 4 facing the liner lower lid 3 and the main shaft 7 in the axial direction. The liner chamber 20 is filled with oil, and a sealing material 80 that prevents the oil from flowing out through a clearance C that is a gap between the outer peripheral surface of the main shaft 7 and the inner peripheral surface of the hole 30 of the liner lower lid 3 is accommodated. In the hydraulic pulse generator P having the seal chamber 8, a recess G is formed on the outer peripheral surface of the main shaft 7 between the liner chamber side opening C 1, which is one end of the clearance C, and the seal chamber side opening C 2 communicating therewith. The impact type tightening tool including the hydraulic pulse generator P, which is characterized by being formed, is the same as described above. However, as shown in FIG. 7, the liner lower lid 3 has a large diameter portion on the rear end side. A seal chamber 8 is formed between the inner peripheral surface of the large-diameter portion 3A of the liner lower lid 3 and the outer peripheral surface of the main shaft 7, and includes a large diameter of the liner lower lid 3. Clearance C is defined by a gap between the inner peripheral surface of the portion 3A and a bowl-shaped large-diameter portion 73 having a relatively larger diameter than the other portion of the main shaft 7 (the portion facing the seal chamber 8 and closing the opening). (Between C1 and C2) is formed, and an annular recess G is formed in the large-diameter portion 73 of the main shaft 7. The concave portion G in the present embodiment is an annular groove that is formed on the outer peripheral surface of the main shaft 7 and opens outward, and has a diameter that is relatively smaller than the diameter of the large diameter portion 73.

  According to the present embodiment, the oil entering through the clearance C from the liner chamber 20 when the hydraulic pulse is generated flows into the recess G that is relatively larger than the clearance C and expands, so that the pressure decreases. Thereafter, 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.

  A third embodiment is shown in FIGS.

  Although it is substantially the same as the said Example 2, it does not form the annular recessed part G in the large diameter part 73 of the main shaft 7 like Example 2, but an annular recessed part is formed in the large diameter part 3A of the liner lower cover 3. FIG. G is formed. The concave portion G in the present embodiment is an annular groove formed on the inner peripheral surface of the liner lower lid 3 and opened inward (in the main shaft direction), and has a diameter relatively larger than the diameter of the large diameter portion 3A. Have

  Example 4 is shown in FIG.

  Also in this embodiment, the main shaft 7 is rotatably inserted into the hole 30 formed in the liner lower lid 3 and the liner lower lid 3 and the main shaft 7 are opposed to each other in the axial direction as in the above embodiments. The liner chamber 20 closed by the liner upper lid 4 is filled with oil, and the oil flows out through the clearance C which is a gap between the outer peripheral surface of the main shaft 7 and the inner peripheral surface of the hole 30 of the liner lower lid 3. In the hydraulic pulse generator P having the seal chamber 8 containing the sealing material 80 to be prevented, the main shaft between the liner chamber side opening C1 which is one end of the clearance C and the seal chamber side opening C2 communicating with the main shaft. 7 is an impact-type tightening tool equipped with a hydraulic pulse generator P characterized in that a concave portion G is formed on the outer peripheral surface of the apparatus 7, but has the following characteristic configuration.

  The hydraulic pulse generator P is provided with an oil passage 31 that communicates between the seal chamber 8 and the liner chamber 20, and an open / close valve V is provided in the oil passage 31. And then. The on-off valve V is composed of a valve body V1 such as a steel ball and a biasing means V2 such as a spring that biases 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 extending in the radial direction of the main shaft 7. Specifically, it 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. As shown in FIG. 10, the constituent surface of the hole 30 is an inner constituent surface of the liner lower lid 3 that faces the outer peripheral surface of the main shaft 7. A seal chamber 8 is formed in the vicinity of the substantially central portion in the axial direction of the configuration surface facing the main shaft 7, and a clearance C is formed between the rear portion and the main shaft 7.

  The oil passage 31 is formed in the liner lower lid 3 and has one end communicating with the seal chamber 8 and the other end communicating with the liner chamber 20. 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 is composed of a small-diameter portion on the front end side facing the main shaft 7 via a clearance C, and a large-diameter portion facing the main shaft 7 via a predetermined interval to form a seal chamber 8. The tip protrusion 33 is fixed by being fitted to the large diameter portion of the outer liner lower lid 32.

  An oil passage 31 is formed in the outer liner lower lid 32 and the inner liner lower lid 33, an upstream oil passage is formed in the outer liner lower lid 32, and a downstream oil passage connected to the upstream oil passage is formed in the inner liner lower lid 33. Is done.

  The outlet of the upstream side oil passage of the outer liner lower lid 32 is closed by the valve body V1, and in order to maintain a good state in which the valve body V1 does not move, a recess in which the valve body V1 can be seated is formed. ing. 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. 11 shows P3 indicating the pressure change in the seal chamber 8 when the oil passage 31 and the opening / closing valve V are not provided, and the pressure change in the present embodiment where the oil passage 31 and the opening / closing 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 the 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. Then, it flows out into the liner chamber 20 and the pressure in the seal chamber 8 is reduced. The on-off valve V, which returns to the closed position when the pressure in the seal chamber 8 decreases, moves to the open position again due to the pressure of the oil flowing into the seal chamber 8 due to the hydraulic pulse generated again. It returns to the closed position by the same action and repeats this.

  Here, as in the prior art shown in FIG. 12, 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 decreases in the pressure in the liner chamber 20. It is conceivable that it will flow out from the clearance C into the liner chamber and return to the liner chamber, but 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. Since the oil in the seal chamber 8 hardly returns to the liner chamber 20 via C, the oil pressure is successively accumulated in the seal chamber 8 every time a hydraulic pulse is generated (P3 in FIG. 11). Will be leaked. 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. Since the valve body moves to the open position against the pressure acting to hold the valve body V1 in the closed position when the pressure becomes larger than the pressure acting in the moving direction, the valve body enters the seal chamber 8. The oil thus returned returns to the liner chamber 20 side 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. 11, 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.

  Instead of forming the annular recess G in the large diameter portion 73 of the main shaft 7, it is also possible to form the annular recess G in the large diameter portion 3 </ b> A of the liner lower lid 3.

  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. FIG. 4 is a partial cross-sectional view of a two-blade impulse wrench having a hydraulic pulse generator of Example 2. Sectional drawing of the said hydraulic pulse generator. FIG. 6 is a partial cross-sectional view of a two-blade impulse wrench having a hydraulic pulse generator of Example 3. Sectional drawing of the said hydraulic pulse generator. Sectional drawing of the hydraulic pulse generator of Example 4. FIG. Diagram showing pressure change Sectional drawing of the conventional hydraulic pulse generator.

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 (2)

  A main shaft (7) is rotatably fitted in a hole (30) formed in the liner lower lid (3), and is opposed to the liner lower lid (3) in the axial direction of the main shaft (7). The liner chamber (20) closed by the liner upper lid (4) is filled with oil, and a gap between the outer peripheral surface of the main shaft (7) and the inner peripheral surface of the hole (30) of the liner lower lid (3) facing the outer surface. In the hydraulic pulse generator (P) having a seal chamber (8) containing a seal material (80) for preventing oil from flowing out through the clearance (C), a liner chamber (one end of the clearance (C) ( 20) Impact type equipped with a hydraulic pulse generator (P) characterized in that a recess (G) is formed on the outer peripheral surface of the main shaft (7) between the side opening (C1) and the seal chamber side opening (C2). Tightening tool.   A main shaft (7) is rotatably fitted in a hole (30) formed in the liner lower lid (3), and a liner upper lid facing the liner lower lid (3) and the main shaft (7) in the axial direction. The liner chamber (20) closed in (4) is filled with oil, and a clearance (a clearance between the outer peripheral surface of the main shaft (7) and the inner peripheral surface of the hole (30) of the liner lower lid (3) ( In the hydraulic pulse generator (P) having a seal chamber (8) containing a seal material (80) for preventing oil from flowing out through C), the liner chamber (20) side opening which is one end of the clearance (C) Impact type tightening equipped with a hydraulic pulse generator (P) characterized in that a recess (G) is formed on the inner peripheral surface of the liner lower lid (3) between (C1) and the seal chamber side opening (C2) tool.

Images