JP5694973B2 - Hydraulic pulse wrench shut-off valve mechanism - Google Patents

Description

  The present invention relates to a shutoff valve mechanism of a hydraulic pulse wrench provided with a hydraulic impact torque generating mechanism.

  For example, Patent Literatures 1 and 2 disclose a hydraulic pulse wrench that intermittently applies a tightening torque to bolts, nuts, and the like via a main shaft by rotating a hydraulic impact torque generating mechanism by an air motor.

  The hydraulic pulse wrench having the above-described configuration is provided with a shut-off valve mechanism that stops air supply to the air motor when a predetermined tightening force is reached. Specifically, the hydraulic striking torque generating mechanism is configured such that a high pressure chamber and a low pressure chamber are provided in the oil cylinder when the tightening load increases by rotating the oil cylinder filled with hydraulic oil by an air motor. And intermittent clamping torque (blow torque) is applied by the hydraulic oil pressure generated in the high-pressure chamber, but when the specified clamping force is reached, the hydraulic oil filled in the high-pressure chamber is relieved. Actuate the piston through the hydraulic oil passage formed on the oil cylinder top lid from the valve, operate the pilot valve via the rod arranged on the back of the piston, and operate the shutoff valve that shuts off the air supply to the air motor The structure to be made is provided.

JP 2011-16204 A JP 2011-25406 A

  By the way, in the shutoff valve mechanism configured as described above, the hydraulic oil supplied to the piston front (opposite to the back) and used for piston operation is returned to the oil cylinder when the air supply to the air motor is stopped. It is supposed to be configured. In other words, the oil chamber (the passage of the liner upper plate in Patent Document 1 and the passage member in Patent Document 2) to which the hydraulic oil is supplied is also opened on the oil cylinder side. Is returned.

  However, conventionally, the oil cylinder side opening of the oil chamber is always in communication with the oil cylinder, that is, a conduction path for guiding the hydraulic oil from the oil cylinder to the oil chamber, and the hydraulic oil to the oil cylinder. The return path is always connected to the return path, so before the supply of air to the air motor is stopped, specifically, immediately after the hydraulic oil is supplied to the oil chamber through the conduction path, The hydraulic oil is returned from the opening on the oil cylinder side to the oil cylinder from the time when the piston is not operating. Therefore, the hydraulic pressure does not sufficiently act on the piston, and the piston operation may become unstable.

  In Cited Document 2, a check valve is provided on the oil cylinder side of the passage member, and the opening on the oil cylinder side of the passage member is closed, but the spring constituting this check valve has a piston on the oil cylinder side. The repulsive force is smaller than that of the energizing spring. Since the hydraulic oil operates the piston against the spring that urges the piston, the check valve, which has a smaller repulsive force than the spring that urges the piston, operates before the piston is activated. Therefore, the hydraulic oil is separated from the passage member, and the return of the hydraulic oil to the oil cylinder before the piston operation cannot be prevented.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a shutoff valve mechanism for a hydraulic pulse wrench that can suppress the return of hydraulic oil to the oil cylinder before the piston is operated. And

In order to solve the above problems, the shutoff valve mechanism of the hydraulic pulse wrench according to the present invention rotates the oil cylinder 11 connected to the motor 6 relative to the main shaft 9 to operate the oil cylinder 11 filled. Oil is caused to flow out from the conduction path 19 to the oil chamber 20, and hydraulic oil pressure is applied to the piston 21 slidably accommodated in the oil chamber 20, thereby supplying the driving fluid to the motor 6. In a shutoff valve mechanism of a hydraulic pulse wrench configured to operate a shutoff valve 24 to be shut off, an oil chamber is connected to a bush 27 that is fitted in the oil chamber 20 and closes the opening of the oil chamber 20 on the oil cylinder 11 side. 20 is provided with a return path 27c for returning the hydraulic oil filled in 20 to the oil cylinder 11 side. By closed by, in before the piston 21 is actuated by the pressure of the working oil is characterized in that it is independent from each other without communicating the return passage 27c and the conductive paths 19.

  Specifically, the bush 27 includes a small-diameter portion 27b at a position facing the conduction path 19 opened in the side wall portion of the oil chamber 20, and the return path 27c provided in the small-diameter portion 27b is connected to the piston. 21 is obstructed.

  More specifically, the oil chamber 20, the piston 21, and the small diameter portion 27b of the bush 27 are provided on the same axis, and the piston 21 is slidable along the axis. ing.

  The piston 21 is urged toward the return path 27c by the urging means.

  Furthermore, a check valve 30 for closing the opening on the oil cylinder 11 side of the return path 27c is provided. The check valve 30 is operated by the pressure of hydraulic oil from the high-pressure introduction hole 9c provided in the rear end portion of the main shaft 9. , Is biased toward the bush 27 side.

  According to the shutoff valve mechanism of the hydraulic pulse wrench of the present invention, the return path is closed by the piston, and the conduction path and the return path are independent, so before the piston is operated by the pressure of the hydraulic oil, The hydraulic oil does not return to the oil cylinder, the pressure of the hydraulic oil can be reliably applied to the piston, and the operation of the piston can be stabilized.

  Further, since the oil chamber, the piston, and the small diameter portion of the bush are provided on the same axis, the pressure of the hydraulic oil can be evenly applied to the piston, and stable piston operation can be ensured.

  Further, since the piston is urged by the urging means, the return path can be reliably closed.

  In addition, since a check valve that closes the opening on the oil cylinder side of the return path is provided, the return of hydraulic oil from the return path to the oil cylinder can be suppressed even if the piston moves due to the pressure of the hydraulic oil. Further, if the pressure of the hydraulic oil from the high-pressure introduction hole is applied to the check valve, the return of the hydraulic oil from the return path to the oil cylinder can be more effectively suppressed.

It is sectional drawing which shows the hydraulic pulse wrench provided with the shut-off valve mechanism which concerns on embodiment of this invention. FIG. 2 is an enlarged view of a main part of FIG. 1.

  Next, an embodiment of a shutoff valve mechanism of a hydraulic pulse wrench of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a cross-sectional view of a hydraulic pulse wrench. The hydraulic pulse wrench 1 includes a grip 2 and a main casing 3 that extends in the front-rear direction at the upper end of the grip 2. The grip 2 is provided with an air supply port 4 and an operation lever 5. A vane type air motor 6 is housed on the rear side of the main casing 3, and a hydraulic impact torque generating mechanism 7 is housed on the front side of the air motor 6.

  As shown in FIG. 1, the hydraulic striking torque generating mechanism 7 has a cylinder case 8 and a main shaft 9 disposed therein, and the cylinder case 8 is driven to rotate by a rotor of the air motor 6. It has become. The main shaft 9 is led out from the front end portion of the main casing 3, and a mounting portion 10 such as a socket (not shown) for turning a bolt or nut is formed at the front end portion. An oil cylinder 11 is formed inside the cylinder case 8 and the oil cylinder 11 is filled with hydraulic oil. On the other hand, the base end portion of the main shaft 9 is inserted and disposed in the oil cylinder 11, and a blade groove 9a is formed in the portion, and a pair of blades 12 are slidably disposed in the blade groove 9a. Yes. The blades 12 are urged by the springs 13 so as to protrude outward in the radial direction, whereby the tip portions of the blades 12 are in sliding contact with the inner peripheral wall of the oil cylinder 11.

  In the hydraulic striking torque generating mechanism 7 having the above configuration, when the cylinder case 8 is rotationally driven by the air motor 6, the rotation of the main shaft 9 becomes dull especially when the tightening load becomes large, and the main shaft 9 and the oil cylinder 11 are driven. The relative rotational position of the blade is changed, but when the seal portion provided in the oil cylinder 11 reaches a specific position where the seal portion provided on the main shaft 9 and the tip of the blade 12 all come into contact with each other, the blade The hydraulic oil is contained on one side of 12, and a high pressure chamber is formed in this portion. Containment of hydraulic fluid does not occur on the side of the blade 12 opposite to the above, and this portion becomes a low pressure chamber having a lower pressure than the above. Then, by confining the pressure in this way, a high pressure is generated in a pulse shape, which acts on the main shaft 9 and is applied to the tightened body as a tightening torque. The cylinder case 8 is provided with a bypass passage 14 for bypassing the high-pressure chamber and the low-pressure chamber, and a communication passage 15 for communicating the bypass passage 14 is formed.

  In the hydraulic pulse wrench 1 having the above-described configuration, a mechanism for automatically stopping the tightening operation of the air motor 6 when a predetermined tightening torque is obtained, a so-called shut-off valve mechanism is further added. ing. First, as shown in FIG. 2, a relief valve 16 is attached to the rear end portion of the communication path 15. The relief valve 16 has a structure in which the ball 17 is pressed and brought into contact with the downstream opening of the communication path 15 with a spring 18. The hydraulic oil pressure in the communication path 15 acts on the ball 17, and the spring 18 Is opposed to the power of A conduction path 19 on the downstream side of the relief valve 16 communicates with an oil chamber 20 provided in the axial center portion of the oil cylinder upper lid 11a. Also, in this oil chamber 20, a piston 21 is housed slidably in the axial direction (axial direction of the motor 6, the cylinder case 8, the main shaft 9, the oil cylinder 11, and the oil cylinder upper lid 11a). The movement of the piston 21 urges the pilot valve 23 provided at the rear end portion of the rod 22 rearward through the rod 22 penetrating the rotor shaft center portion of the air motor 6, and the pilot valve 23, the shut-off valve 24, The air is supplied during this time, and the shutoff valve 24 is moved forward by the pressure of the air so that the air supply passage 25 extending from the air supply port 4 to the air motor 6 is closed by the shutoff valve 24. It is configured. That is, during the tightening operation, when a predetermined peak pressure is generated in the high pressure chamber and the hydraulic oil pressure in the communication passage 15 exceeds the predetermined pressure, the relief valve 16 opens against the force of the spring 18. The hydraulic oil that has been relieved by opening the relief valve 16 flows into the oil chamber 20 and pushes the piston 21, operates the pilot valve 23 via the rod 22, and operates the air motor 6 with the shutoff valve 24. The air supply to is shut off and the tightening operation is stopped.

  In the above configuration, when the air supply to the air motor 6 is shut off, the pressure of the hydraulic oil decreases, and the pilot valve 23 is moved to a fixed position (operated by the biasing force of the spring 26 that biases the pilot valve 23 forward. Return to the position before being pushed by oil. Further, when the pilot valve 23 is returned to the fixed position, the rod 22 and the piston 21 are also returned to the fixed positions before being pushed by the hydraulic oil.

  By the way, the oil chamber 20 is formed in a substantially cylindrical shape that opens to the rod 22 side and the oil cylinder 11 side. The rod 22 side is closed by the piston 21 and the oil cylinder 11 side is closed by the bush 27. . When the bush 27 is fitted in the oil chamber 20, the bush 27 comes into contact with the peripheral wall portion (side wall portion) of the oil chamber 20 and closes the opening of the oil chamber 20 toward the oil cylinder 11, and the oil A small-diameter portion 27b that forms a space in which hydraulic oil can be filled between the peripheral wall portion of the chamber 20 and the shaft portion penetrates from the oil cylinder 11 side to the piston 21 side. A return path 27c is formed for returning the hydraulic oil filled in to the oil cylinder 11 side. The oil chamber 20, the piston 21, and the bush 27 (large diameter portion 27 a, small diameter portion 27 b) are located on the same axis, and the hydraulic oil pressure is equally applied to the piston 21. It is like that.

  As shown in FIG. 2, the piston 21 positioned at a fixed position is in contact with the opening of the return path 27 c on the piston 21 side. That is, the return path 27c is closed by the piston 21, and the conduction path 19 and the return path 27c do not communicate with each other and are independent from each other. Therefore, during the tightening operation, when a predetermined peak pressure is generated in the high pressure chamber and the hydraulic oil pressure in the communication passage 15 exceeds the predetermined pressure, the relief valve 16 opens against the force of the spring 18. Even if the hydraulic oil that has been relieved by opening the relief valve 16 flows into the oil chamber 20 through the conduction path 19, the hydraulic oil does not return to the oil cylinder 11 before the piston 21 is activated. Absent.

  A check valve 30 comprising a valve body 28 and a spring 29 for urging the valve body 28 toward the return path 27c is provided in the recess 9b provided at the rear end of the main shaft 9, and the return path 27c. The oil cylinder 11 side opening is closed. Further, a high-pressure introduction hole 9 c communicating with the oil cylinder 11 is provided in the recess 9 b at the rear end portion of the main shaft 9. Therefore, even if the piston 21 is operated and the opening on the piston 21 side of the return path 27c of the bush 27 is opened, the bushing is caused by the hydraulic oil flowing into the check valve 30 side from the high pressure introduction hole 9c in addition to the biasing force of the spring 29. By the check valve 30 biased in the 27 direction, the opening on the oil cylinder 11 side of the return path 27c is kept closed. Therefore, the pressure of the hydraulic oil can be continuously applied to the piston 21 and the stable operation of the piston 21 can be ensured. As a result, the operation of the pilot valve 23 and the stable operation of the shutoff valve 24 can be ensured, and a stable tightening force can be obtained.

  The hydraulic oil filled in the oil chamber 20 and used for operating the piston 21 is provided with a spring 26 that urges the pilot valve 23 forward (fixed position side) after the air supply to the air motor 6 is shut off. The force returns to the oil cylinder 11 through the return path 27c. At this time, since the urging force of the spring 29 of the check valve 30 is smaller than the urging force of the spring 26 of the pilot valve 23 and the pressure of the hydraulic oil is reduced, the oil cylinder 11 in the return path 27c. The check valve 30 that has closed the opening on the side is opened, and the hydraulic oil can be smoothly returned to the oil cylinder 11 via the return path 27c.

  As described above, in the shutoff valve mechanism of the hydraulic pulse wrench 1 of the present invention, the piston 21 is operated because the return path 27c that uniquely communicates the oil chamber 20 and the oil cylinder 11 is closed by the piston 21. It is possible to reliably prevent the hydraulic oil from returning to the oil cylinder 11 before the operation.

  Although specific embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. For example, in the above-described embodiment, the spring 26 of the pilot valve 23 is used to return the piston 21 to the home position. However, a spring for returning the piston 21 to the home position is separately provided without depending on this. It may be provided, and not only a spring but also air pressure or the like may be used. That is, what is necessary is just to be able to urge the piston 21 toward the fixed position. Further, the hydraulic striking torque generation mechanism 7 can be replaced with another known method regardless of the configuration described above. In short, any configuration that allows hydraulic oil to act on the piston 21 in a state where a predetermined tightening force has been achieved may be used. Further, the pilot valve 23 and the shut-off valve 24 can be replaced with various known configurations. Further, in order to form a space that can be filled with hydraulic oil between the piston 21 and the large diameter portion 27 a of the bush 27, the small diameter portion 27 b is provided at a position facing the opening of the conduction path 19. A small-diameter portion may be formed on the bush 27 side, or a spacer or the like may be separately interposed. That is, it is only necessary to form a space that communicates with the conduction path 19 and can be filled with hydraulic oil between the piston 21 and the large-diameter portion 27 a of the bush 27.

  1 .... Hydraulic pulse wrench, 6 .... Air motor, 9 .... Spindle, 9c ... High pressure introduction hole, 11 .... Oil cylinder, 19 .... Conducting path, 20 .... Oil chamber, 21 ... Piston, 24 ... Shut-off valve, 27 ・ ・ Bush, 27b ・ ・ Small diameter part 27c ・ ・ Return path, 30 ・ ・ Check valve

Claims (6)

The oil cylinder (11) connected to the motor (6) is rotated relative to the main shaft (9), and the hydraulic oil filled in the oil cylinder (11) is supplied from the conduction path (19) to the oil chamber (20 ) And the hydraulic fluid pressure is applied to the piston (21) slidably accommodated in the oil chamber (20) to cut off the supply of driving fluid to the motor (6). In the shut-off valve mechanism of the hydraulic pulse wrench configured to operate the shut-off valve (24), the shut-off valve mechanism is fitted into the oil chamber (20) and closes the opening on the oil cylinder (11) side of the oil chamber (20). A return path (27c) for returning the hydraulic oil filled in the oil chamber (20) to the oil cylinder (11) side is provided in the bush (27), and this return path (27c) is provided as the piston (21). By closed by said piston (21) in the previous operated by the pressure of the hydraulic fluid, characterized in that it is independent of each other without communicating the said conductive paths (19) and the return passage (27c) Hydraulic pulse wrench shut-off valve mechanism.   The bush (27) includes a small-diameter portion (27b) at a position facing the conduction path (19) opened in the side wall portion of the oil chamber (20), and the return provided in the small-diameter portion (27b). The shutoff valve mechanism for a hydraulic pulse wrench according to claim 1, wherein the passage (27c) is closed by the piston (21).   The oil chamber (20), the piston (21), and the small diameter portion (27b) of the bush (27) are provided on the same axis, and the piston (21) slides along the axis. The shut-off valve mechanism for a hydraulic pulse wrench according to claim 2, wherein the shut-off valve mechanism is movable.   The shut-off valve mechanism for a hydraulic pulse wrench according to any one of claims 1 to 3, wherein the piston (21) is biased toward the return path (27c) by a biasing means.   The shutoff valve for a hydraulic pulse wrench according to any one of claims 1 to 4, further comprising a check valve (30) for closing an opening on the oil cylinder (11) side of the return path (27c). mechanism.   The check valve (30) is biased toward the bush (27) by the pressure of hydraulic oil from a high-pressure introduction hole (9c) provided at the rear end of the main shaft (9). A shutoff valve mechanism for a hydraulic pulse wrench according to claim 5.