JP2002361570A - Hammering torque generator of hydraulic torque wrench - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hammering torque generator of a hydraulic torque wrench capable of reducing a production cost by simplifying the structure of an oil amount regulating mechanism for absorbing thermally expanded working oil. SOLUTION: This hammering torque generator of the hydraulic torque wrench comprises a liner 7 rotated by a rotor 4 and a spindle 8 and a vane 9 disposed inside the liner 7. An oil storage chamber 31 communicating with the hollow of the liner 7 is formed, and a pressure regulating member 34 storing gas therein and contracting according to the rise of hydraulic pressure is disposed in the oil storage chamber 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a striking torque generating device for a hydraulic torque wrench, and more particularly, to a structure of an oil amount adjusting mechanism for absorbing thermally expanded hydraulic oil, thereby reducing manufacturing costs. The present invention relates to a striking torque generating device for a hydraulic torque wrench.

[0002]

2. Description of the Related Art A hydraulic torque wrench using a hydraulic impact torque generating device with small noise and vibration has been developed and put into practical use as a torque wrench generating device for a torque wrench. FIG. 6 shows an example of this hydraulic torque wrench. The hydraulic torque wrench 11 supplies high-pressure air,
It has a main valve 12 for stopping and a forward / reverse rotation switching valve 13 for selectively generating a forward / reverse rotation impact torque, and generates a rotational torque by high-pressure air supplied through the valves 12, 13. A hydraulic striking torque generator 15 that drives the rotor 14 and converts the rotational torque of the rotor 14 into striking torque is provided in a case 16 of the hydraulic torque wrench 11.

[0003] The hydraulic impact torque generating device 15
The cavity formed in the liner 17 rotated by the rotor 14 is filled with hydraulic oil and sealed, and one (or more) blade insertion groove is provided in the main shaft 18 coaxially inserted in the liner 17 to insert the blade. The blades 19 are inserted into the grooves, and the blades 19 are constantly urged by the springs 20 outward in the radial direction of the main shaft 18 so as to contact the inner peripheral surface of the liner 17. And
When the plurality of sealing surfaces formed on the inner peripheral surface of the liner 17 match the sealing surfaces formed on the outer peripheral surface of the main shaft 18 and the blades 19 by rotating the liner 17 by the rotor 14, the main shaft 18 is hit. A torque is generated to tighten or loosen a nut or the like engaged with the tip of the main shaft 18.

Incidentally, in this type of hydraulic torque wrench, this type of hydraulic impact torque generating device is usually used for a long period of time when the operating oil filled in the cavity formed in the liner 7 is heated. In some cases, the hydraulic oil expands and the hydraulic oil expands, thereby hindering the operation. In order to prevent this, it is necessary to provide an oil amount adjusting mechanism for absorbing the expanded hydraulic oil. As shown in FIG. 6, the oil amount adjusting mechanism 21 is provided on the body of the liner 17 so as to be parallel to the central axis.
1a, the oil storage chamber 21a and a cavity formed in the liner 17 (a side which becomes a low pressure chamber when the liner 17 is rotated in a predetermined direction) are communicated via an oil flow path 21b. The oil in the oil storage chamber 21a is pressurized at a predetermined pressure by interposing a spring 21e between the lid 21c of the oil storage chamber 21a and the piston 21d arranged in the oil storage chamber 21a. , And a predetermined amount of hydraulic oil is always filled in the cavity formed in the liner 17.

[0005]

However, in the above-mentioned conventional hydraulic torque wrench, an oil amount adjusting mechanism for absorbing the thermally expanded hydraulic oil is provided with a piston disposed in the oil storage chamber and a spring for urging the piston. Therefore, there is a problem that the number of parts is increased, and a seal mechanism is required for the piston, which complicates the structure and increases the manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of the conventional hydraulic torque wrench impact torque generating apparatus, and has a simplified structure of an oil amount adjusting mechanism for absorbing thermally expanded hydraulic oil, thereby reducing manufacturing costs. It is an object of the present invention to provide a striking torque generating device for a hydraulic torque wrench that can perform the above.

[0007]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, there is provided an impact torque generating apparatus for a hydraulic torque wrench, comprising: a liner rotated by a rotor; a main shaft and blades disposed inside the liner. In the impact torque generating device for a hydraulic torque wrench, the oil storage chamber communicating with the cavity of the liner is formed, and the oil storage chamber is provided with a pressure adjusting member that accommodates gas therein and contracts when the oil pressure rises. It is characterized by the following.

[0008] In this hydraulic torque wrench, the striking torque generator is provided with a pressure adjusting member which accommodates gas therein and contracts by an increase in hydraulic pressure, in an oil storage chamber communicating with the cavity of the liner. When the hydraulic oil is thermally expanded and the hydraulic pressure is increased, the expanded hydraulic oil is absorbed by contraction of the pressure adjusting member, and pressure can be adjusted.
Since the pressure adjusting member only needs to have a structure in which gas is housed inside, the pressure adjusting member can be disposed in the oil storage chamber with a small number of parts and without the need for a seal mechanism. It can be simplified.

[0009] In this case, the cavity of the liner and the oil storage chamber are communicated with each other through the oil flow path, and the opening of the oil flow path is set to a position closed by the side end surface of the blade when the impact torque is generated. Can be formed.

[0010] With this configuration, when the impact torque is generated, the opening of the oil flow path that connects the cavity of the liner and the oil storage chamber is closed by the side end surface of the blade, so that the oil storage chamber side and the high-pressure chamber of the liner close the oil flow path. Thus, the hydraulic oil in the high-pressure chamber is prevented from flowing into the oil storage chamber, and a stable high impact torque can be obtained.

According to another aspect of the present invention, there is provided a hydraulic torque wrench according to a second aspect of the present invention, wherein the hydraulic torque wrench includes a hydraulic torque wrench comprising a liner rotated by a rotor, a main shaft and blades disposed inside the liner. A striking torque generating device for a torque wrench, wherein an air chamber is formed adjacent to the cavity of the liner, the air chamber is sealed with an elastic film, and hydraulic pressure acts on the elastic film. .

In the hitting torque generator of this hydraulic torque wrench, an air chamber is formed adjacent to the cavity of the liner, and the air chamber is sealed by an elastic film. When the pressure rises, the elastic film protrudes toward the air chamber, thereby absorbing the expanded operating oil and adjusting the pressure. The oil amount adjusting mechanism includes an air chamber formed adjacent to the cavity of the liner and an elastic film that seals the air chamber, so that the number of parts can be reduced. The structure can be simplified.

In this case, the oil pressure is applied to the elastic film via the oil flow passage, and the opening of the oil flow passage is formed at a position closed by the side end surface of the blade when the impact torque is generated. be able to.

Accordingly, the opening of the oil flow path for applying hydraulic pressure to the elastic film is closed by the side end surface of the blade when the impact torque is generated, so that the hydraulic film of the high-pressure chamber is supplied to the elastic film via the oil flow path. A stable high impact torque can be obtained by preventing the hydraulic pressure from acting.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a hydraulic torque wrench according to the present invention.

1 to 3 show a first embodiment of a striking torque generating device for a hydraulic torque wrench according to the present invention. The basic structure of the wrench itself of this hydraulic torque wrench is the same as the conventional hydraulic torque wrench shown in FIG. 6 except for an oil amount adjusting mechanism 30 described later. A main valve 2 for stopping and a forward / reverse rotation switching valve 3 for selectively generating forward / reverse rotation impact torque, and a rotational torque is generated by high-pressure air supplied through the valves 2 and 3. A hydraulic impact torque generator 5 that converts the rotational torque of the rotor 4 into an impact torque is provided in the case 6 of the hydraulic torque wrench 1.

The hydraulic striking torque generator 5 fills a cavity formed in the liner 7 rotated by the rotor 4 with hydraulic oil, seals the same, and inserts one or more of the main shafts 8 into the liner 7 coaxially. A plurality of blade insertion grooves are provided, and the blades 9 are respectively inserted into the blade insertion grooves, and the blades 9 are constantly urged radially outward of the main shaft 8 by a spring 10 so as to contact the inner peripheral surface of the liner 7. To be configured. When the plurality of sealing surfaces formed on the inner peripheral surface of the liner 7 match the sealing surfaces formed on the outer peripheral surface of the main shaft 8 and the blades 9 by rotating the liner 7 by the rotor 4, the main shaft 8 is rotated. And a nut or the like engaged with the tip of the main shaft 8 is tightened or loosened.

In this embodiment, as shown in FIG. 2, four sealing surfaces projecting in a mountain shape are formed on the inner peripheral surface of a cavity formed inside the liner 7 into which the main shaft 8 is inserted. ing. The tip of the blade 9 contacts the liner 7
Sealing surfaces 71 for sealing a cavity formed inside
Are provided at positions that are 180 ° rotationally symmetric to each other, and
The other two sealing surfaces 72 that contact the sealing surface 82 formed on the main shaft 8 to seal the cavity formed inside the liner 7
Is that each sealing surface 72 is 180
It is provided at a position substantially at the center of the rotationally symmetrical seal surface 71 and at a position where the respective seal surfaces 72 are rotationally asymmetrical by 180 ° with respect to each other.

In the main shaft 8 disposed coaxially inside the liner 7, two blades 9 are inserted into the blade insertion grooves 81, and two sealing surfaces protruding in a mountain shape on the peripheral surface. 8
Form 2 And the two blades 9 are 180
At the position where the rotation is symmetrical, the two sealing surfaces 82 are substantially intermediate between the two mutually 180 ° rotationally symmetric blades 9 and the respective sealing surfaces 82 are 180 It is provided at a position where rotation is asymmetric, and at a position where a cavity formed inside the liner 7 in contact with the two sealing surfaces 72 formed on the liner 7 can be sealed.

Thus, in the impact torque generating device 5 of the present embodiment, by rotating the liner 7 by the rotor 4, the sealing surface 71 of the liner 7 and the tip of the blade 9 of the main shaft 8 coincide with each other. When the sealing surface 72 of the main shaft 8 and the sealing surface 82 of the main shaft 8 coincide with each other, four cavities inside the liner 7 are formed of the high-pressure chamber H and the low-pressure chamber L (however, the high-pressure chambers H are connected via the blade insertion grooves 81). Communication.)
Thus, one intermittent impact torque can be generated for one rotation of the liner 7 on the main shaft 8 (one rotation relative to the main shaft 8) (FIG. 2A). Further, when the rotor 4 is reversed, one intermittent impact torque can be generated per one rotation of the liner in the direction opposite to the direction preceding the main shaft 8 (one rotation relative to the main shaft 8) ( FIG. 2 (b). The details of the impact torque generator 5 are disclosed in Japanese Utility Model Publication No. 1-201212.

On the other hand, the hydraulic torque wrench 1 has an oil amount adjusting mechanism 30. This oil amount adjustment mechanism 30
As shown in FIG. 3, a ring-shaped oil storage chamber 31 is formed in the liner upper lid 73, and the oil storage chamber 31 and the cavity formed in the liner 7 are connected to the oil passage 3 of the partition plate 70 of the liner upper lid 73.
In addition, a ring-shaped pressure adjusting member 34 that communicates with the oil reservoir 2 through air and accommodates gas such as air therein and contracts when the oil pressure rises is disposed in the oil storage chamber 31. The ring-shaped pressure adjusting member 34 is formed of a structure for accommodating a gas therein, more specifically, in the present embodiment, a foamed material (closed cell material) having closed cells. However, in addition, a hollow structure may be used. By disposing the pressure adjusting member 34 in the oil storage chamber 31 as described above, when the hydraulic oil thermally expands and the hydraulic pressure increases, the pressure adjusting member 34 contracts as shown in FIG. Thus, the expanded operating oil can be absorbed, and the pressure can be adjusted. Conversely, when the temperature of the hydraulic oil decreases and the hydraulic pressure decreases, the pressure can be adjusted by expanding the pressure adjusting member 34 as before. The pressure adjusting member 34 may be provided in the oil storage chamber 31 with a small number of parts and without a sealing mechanism, since the pressure adjusting member 34 may have a structure that accommodates gas therein. Can be simplified, and the manufacturing cost of the hydraulic torque wrench can be reduced. The pressure adjusting member 34 can be manufactured using any elastic material that can be elastically deformed. In particular, the pressure adjusting member 34 is hardly deteriorated by hydraulic oil, and is preferably made of a nitrile resin-based rubber (for example, hydrogenated nitrile rubber) or fluorine. It is preferable to use an elastic material such as a resin rubber or a urethane resin rubber.

In this case, as shown in FIG. 3, the oil flow path 32 is located at a position where the side end surface of the blade 9 is closed by the side end surface of the blade 9 when the striking plate 70 of the liner upper lid 73 in which the side end surface of the blade 9 slides is generated. It is open. As a result, the opening of the oil flow passage 32 communicating with the oil storage chamber 31 is closed by the side end surface of the blade 9 when the impact torque is generated.
And the high-pressure chamber H of the liner 7 do not communicate with each other via the oil flow path 32, thereby preventing the hydraulic oil in the high-pressure chamber H from flowing into the oil storage chamber 31 and obtaining a stable and high impact torque. Becomes

FIG. 4 shows a second embodiment of a striking torque generating device for a hydraulic torque wrench according to the present invention. In the second embodiment, there is no difference in the basic structure and operation from the first embodiment except for a part of the oil amount adjusting mechanism 30. Therefore, only the impact torque generating device is illustrated, and the oil amount adjusting mechanism is described. I will explain only.

In the oil amount adjusting mechanism 30 of the second embodiment, a plurality of perforated oil storage chambers 31 are formed in the liner upper lid 73.
The oil storage chamber 31 and the cavity formed in the liner 7 communicate with each other through the oil flow path 32 of the partition plate 70 of the liner upper lid 73, and the oil is stored in the oil storage chamber 31 and contracted by an increase in hydraulic pressure. A plurality of cylindrical pressure adjusting members 35
Is arranged. The cylindrical pressure adjusting member 35 has a structure in which gas is accommodated inside, more specifically, a hollow structure in the present embodiment. In addition, a foamed material (closed cell material) having closed cells Can also be formed. By arranging the pressure adjusting member 35 in the oil storage chamber 31 as described above, when the hydraulic oil thermally expands and the hydraulic pressure increases, the pressure adjusting member 34 contracts as shown in FIG. 4D. Thus, the expanded operating oil can be absorbed, and the pressure can be adjusted. Conversely, when the temperature of the hydraulic oil decreases and the hydraulic pressure decreases, the pressure can be adjusted by expanding the pressure adjusting member 35 as before. The pressure adjusting member 35 may be disposed in the oil storage chamber 31 with a small number of components and without a seal mechanism, since the pressure adjusting member 35 may have a structure that accommodates gas therein. Simplifies the structure of
The manufacturing cost of the hydraulic torque wrench can be reduced. The pressure adjusting member 35 can be manufactured using any elastically deformable elastic material as in the first embodiment. In particular, a nitrile resin-based rubber (for example, , A hydrogenated nitrile rubber), a fluororesin-based rubber, a urethane resin-based rubber, or the like.

As in the first embodiment, the oil flow passage 32 is located at a position where the side end surface of the blade 9 is closed by the side end surface of the blade 9 when a striking torque is applied to the partition plate 70 of the liner upper lid 73 where the side end surface of the blade 9 slides. It is open. As a result, the opening of the oil flow passage 32 communicating with the oil storage chamber 31 is closed by the side end surface of the blade 9 when the impact torque is generated.
And the high-pressure chamber H of the liner 7 do not communicate with each other via the oil flow path 32, thereby preventing the hydraulic oil in the high-pressure chamber H from flowing into the oil storage chamber 31 and obtaining a stable and high impact torque. Becomes

FIG. 5 shows a third embodiment of the impact torque generating device for a hydraulic torque wrench according to the present invention. In the third embodiment, there is no difference in the basic structure and operation from the first embodiment except for a part of the oil amount adjusting mechanism 30. Therefore, only the impact torque generating device is illustrated, and the oil amount adjusting mechanism is described. I will explain only.

In the oil amount adjusting mechanism 30 of the third embodiment, a ring-shaped air chamber 31A is formed in the liner upper lid 73, and this air chamber 31A is bonded to the partition plate 70 of the liner upper lid 73 in a ring shape. In addition to sealing with the membrane 36, oil pressure acts on the elastic membrane 36 through the oil passage 32 of the partition plate 70 of the liner upper lid 73. As described above, by sealing the air chamber 31A with the elastic film 36, when the hydraulic oil thermally expands and the hydraulic pressure rises, FIG.
As shown in (d), the elastic film 36 protrudes toward the air chamber 31A, thereby absorbing the expanded operating oil and adjusting the pressure. Conversely, when the temperature of the hydraulic oil decreases and the hydraulic pressure decreases, the pressure can be adjusted by returning the elastic film 36 to the original state. And
The oil amount adjusting mechanism 30 includes an air chamber 31A and the air chamber 31.
Since it is made of the elastic film 36 for sealing A, the number of parts can be reduced, whereby the structure of the oil amount adjusting mechanism 30 can be simplified, and the manufacturing cost of the hydraulic torque wrench can be reduced. The elastic film 36 can be manufactured using any elastic material that can be elastically deformed. In particular, a nitrile resin-based rubber (for example, hydrogenated nitrile rubber), a fluorine resin, It is preferable to use an elastic material such as a base rubber or a urethane resin base rubber.

Further, as in the first embodiment, the oil flow passage 32 is located at a position where the side end surface of the blade 9 is closed by the side end surface of the blade 9 when a striking torque of the partition plate 70 of the liner upper lid 73 is brought into contact. It is open. This closes the opening of the oil passage 32 for applying oil pressure to the elastic film 36 by the side end surface of the blade 9 when the impact torque is generated. By preventing the hydraulic pressure of the H hydraulic oil from acting, a stable and high impact torque can be obtained.

In each of the above embodiments, the liner 7
Seal surfaces 72 and two seal surfaces 82 of the spindle 8
By forming the respective sealing surfaces so as to be 180 ° rotationally asymmetric with respect to each other, the two sealing surfaces 72 of the liner 7 and the two
Of the sealing surfaces 82 so that
Although the intermittent impact torque is generated once per rotation of the liner 7 on the main shaft 8, the impact torque generating device of the hydraulic torque wrench of the present invention is limited to that of the present embodiment. The two sealing surfaces 72 of the liner 7
And by forming the two sealing surfaces 82 of the main shaft 8 such that the respective sealing surfaces are 180 ° rotationally symmetric with respect to each other, two rotations of the liner 7 twice per rotation of the liner 7.
And the two sealing surfaces 82 of the main shaft 8 are aligned with each other, so that the main shaft 8 has one of the liners 7.
It may be configured to generate an intermittent impact torque twice per rotation. Further, the number of seal surfaces formed on the liner 7 and the number of blades disposed on the main shaft 8 and the number of seal surfaces formed on the main shaft 8 are not limited to those of the present embodiment. Or three or more.

Further, an oil storage chamber is formed in the liner lower lid 74 shown in FIG. 3, and the oil storage chamber and the cavity formed in the liner 7 are communicated with each other through an oil flow path of a partition plate of the liner lower lid 74. It is also possible to dispose the pressure adjusting member in the oil storage chamber.

As mentioned above, the hydraulic striking torque generating device for a wrench of the present invention has been described based on a plurality of embodiments. However, the present invention is not limited to the configuration described in the above embodiment. For example, an electric motor may be used in place of the rotor 4 as a rotation drive source for rotating the motor 7, and the configuration thereof can be appropriately changed without departing from the gist of the motor.

[0032]

According to the striking torque generating device of the hydraulic torque wrench according to the first aspect of the present invention, a pressure adjusting member which accommodates gas therein and contracts by an increase in oil pressure is provided in the oil storage chamber communicating with the liner cavity. Since the hydraulic oil is thermally expanded and the hydraulic pressure is increased, the pressure adjusting member contracts to absorb the expanded hydraulic oil and adjust the pressure. Since the pressure adjusting member only needs to have a structure in which gas is housed inside, the pressure adjusting member can be disposed in the oil storage chamber with a small number of parts and without the need for a seal mechanism. The simplification can reduce the manufacturing cost of the hydraulic torque wrench.

Further, the cavity of the liner and the oil storage chamber are communicated with each other through the oil flow path, and the opening of the oil flow path is formed at a position closed by the side end face of the blade when the impact torque is generated. With this, when the impact torque is generated, the opening of the oil flow path that connects the cavity of the liner and the oil storage chamber is closed by the side end surface of the blade, so that the oil storage chamber side and the high-pressure chamber of the liner communicate through the oil flow path. As a result, it is possible to prevent the hydraulic oil in the high-pressure chamber from flowing into the oil storage chamber and obtain a stable and high impact torque.

According to the impact torque generating device of the hydraulic torque wrench of the second invention, an air chamber is formed adjacent to the cavity of the liner, and the air chamber is sealed with an elastic film. When the hydraulic oil is thermally expanded and the hydraulic pressure is increased, the expanded hydraulic oil is absorbed by the elastic film protruding toward the air chamber, so that the pressure can be adjusted.
The oil amount adjusting mechanism includes an air chamber formed adjacent to the cavity of the liner and an elastic film that seals the air chamber, so that the number of parts can be reduced. The structure can be simplified, and the manufacturing cost of the hydraulic torque wrench can be reduced.

In addition, by making the oil pressure act on the elastic film via the oil flow path, the opening of the oil flow path is formed at a position closed by the side end surface of the blade when the impact torque is generated. Since the opening of the oil flow path for applying hydraulic pressure to the elastic film when the impact torque is generated is closed by the side end surfaces of the blades, the hydraulic pressure of the hydraulic oil in the high-pressure chamber acts on the elastic film via the oil flow path. And a stable high impact torque can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall view of a hydraulic torque wrench incorporating a striking torque generating device according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views orthogonal to the axis of the impact torque generating device according to the embodiment, in which FIG. 2A is a cross-sectional view at the time of normal rotation, and FIG.

FIG. 3 shows the impact torque generating device of the embodiment, and (a)
Is a sectional view parallel to the axis, (b) is a front view of the pressure adjusting member,
(C) is a sectional view of the pressure adjusting member, and (d) is an explanatory diagram showing a state in which the hydraulic oil has thermally expanded.

4A and 4B show an impact torque generating device according to a second embodiment of the present invention, wherein FIG. 4A is an axially parallel sectional view, FIG. 4B is a front view of a pressure adjusting member, and FIG. 4C is a side view of the pressure adjusting member. And (d) is an explanatory diagram showing a state in which the hydraulic oil has thermally expanded.

5A and 5B show an impact torque generating device according to a third embodiment of the present invention, wherein FIG. 5A is an axially parallel sectional view, FIG. 5B is a side view of an elastic film adhered to a partition plate, and FIG. (D) is an explanatory diagram showing a state in which hydraulic oil is thermally expanded.

FIG. 6 is an overall view of a hydraulic torque wrench incorporating a conventional impact torque generating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic torque wrench 2 Main valve 3 Forward / reverse rotation switching valve 4 Rotor 5 Impact torque generator 7 Liner 70 Partition plate 73 Liner upper lid (liner lid) 74 Liner lower lid (liner lid) 8 Main shaft 9 Blade 30 Oil amount Adjusting mechanism 31 Oil storage chamber 31A Air chamber 32 Oil flow path 34 Pressure adjusting member 35 Pressure adjusting member 36 Elastic membrane H High pressure chamber L Low pressure chamber

Claims (4)

[Claims] 1. A striking torque generating device for a hydraulic torque wrench comprising a liner rotated by a rotor, a main shaft and blades disposed inside the liner, wherein an oil storage chamber communicating with a cavity of the liner is formed. A striking torque generating device for a hydraulic torque wrench, characterized in that a pressure adjusting member that accommodates gas therein and contracts when the oil pressure rises is disposed in the oil storage chamber. 2. A method according to claim 1, wherein the liner cavity and the oil storage chamber communicate with each other through an oil flow path, and the opening of the oil flow path is
2. A striking torque generating device for a hydraulic torque wrench according to claim 1, wherein the striking torque generating device is formed at a position closed by a side end surface of the blade when striking torque is generated. 3. A striking torque generating device for a hydraulic torque wrench comprising a liner rotated by a rotor, a main shaft and blades disposed inside the liner, wherein an air chamber is formed adjacent to the cavity of the liner. A striking torque generating device for a hydraulic torque wrench, wherein the air chamber is sealed with an elastic film and a hydraulic pressure acts on the elastic film. 4. The method according to claim 1, wherein a hydraulic pressure acts on the elastic film via an oil flow path, and an opening of the oil flow path is formed at a position closed by a side end face of the blade when an impact torque is generated. The impact torque generating device for a hydraulic torque wrench according to claim 3, wherein: