Impact torque adjusting device for hydraulic torque wrench

Abstract

To provide an impact torque adjusting device of a hydraulic torque wrench capable of improving fastening accuracy and energy efficiency by reducing resistance of hydraulic fluid of an impact torque generating device of the hydraulic torque wrench and shortening fastening time.SOLUTION: In a liner 7, a cylinder part 14a and a 11f are formed in parallel with a rotary shaft, and hydraulic fluid flow passages 14c and 11b opened to the cylinder part 14a and the 11f and communicating the inside of the liner 7 becoming a high pressure chamber H and a low pressure chamber L through the cylinder part 14a and the 11f when hammering torque is generated are formed. An auto-relief mechanism 14 and an output-adjusting mechanism 11 serving also as an auto-relief mechanism are provided, in which a cylindrical valve-element 14a and a cylindrical valve-element 11f are rotatably disposed in a cylinder-part 14b and a cylinder-part 11g, respectively, the valve-element 14b and the valve-element 11g being provided with cut-out parts LA' and LA', respectively, which serve as flow passages for hydraulic fluid, in their peripheral surface parts.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an impact torque adjusting device for a hydraulic torque wrench. [Background technology]

[0002] BACKGROUND ART Conventionally, hydraulic torque wrenches using hydraulic impact torque generators that produce little noise and vibration have been developed and put to practical use as impact torque generators for torque wrenches (see, for example, Patent Documents 1 and 2).

[0003] Figures 9 and 10 show an example of a hydraulic torque wrench. This hydraulic torque wrench 1 has a main valve 2 that starts and stops the supply of high-pressure air and a forward / reverse rotation switching valve 3 that selectively generates forward and reverse rotation impact torque. A rotor 4 that generates rotational torque is driven by the high-pressure air supplied via both valves 2, 3. A hydraulic impact torque generator 5 that converts the rotational torque of the rotor 4 into impact torque is provided within a case 6 of the hydraulic torque wrench 1. The hydraulic impact torque generator 5 is configured such that a cavity formed in a liner 7 rotated by a rotor 4 is filled with hydraulic oil and sealed, a main shaft 8 is coaxially inserted into the liner 7, and two (sometimes one or more than three) blade insertion grooves are provided in the main shaft 8, blades 9 are inserted into the blade insertion grooves, and the blades 9 are constantly urged toward the outer periphery of the main shaft 8 by a spring 10 so as to abut against the inner circumferential surface of the liner 7. The impact torque generating device 5 is also provided with an output adjusting mechanism 11 so that the magnitude of the impact torque to be generated can be adjusted. When the rotor 4 rotates the liner 7, the multiple seal surfaces formed on the inner surface of the liner 7 come into contact with the seal surfaces formed on the outer surface of the main shaft 8 and the blades 9, generating an impact torque on the main shaft 8, which tightens or loosens a nut or the like engaged with the tip of the main shaft 8.

[0004] In conventional hydraulic torque wrenches, the output adjustment mechanism 11 that adjusts the magnitude of the impact torque is configured to adjust the size of the hydraulic oil flow path that connects the inside of the liner 7, which becomes a high-pressure chamber and a low-pressure chamber when impact torque is generated, by operating the operating shaft (specifically, by operating the operating shaft to the open side, the hydraulic oil flow path is enlarged, thereby reducing the magnitude of the impact torque, and conversely, by operating the operating shaft to the close side, the hydraulic oil flow path is narrowed, thereby increasing the magnitude of the impact torque). However, the size of the hydraulic oil flow path, which is adjusted by operating the operating shaft, remains constant (fixed) during operation of the hydraulic torque wrench, which causes the following problems (1) to (4): (1) There is a large error between the magnitude of the impact torque that is actually generated and the magnitude of the impact torque that is set. (2) An abnormally high impact torque is likely to occur at the start of the tightening operation (when the tightening member is seated). (3) The resistance after the impact torque is generated (after the pulse is generated) is large, and the impact torque generation cycle is long. (4) The seal is easily subjected to load pressure, resulting in poor durability.

[0005] To address this issue, the present applicant has proposed an impact torque adjusting device for a hydraulic torque wrench that is equipped with an output adjustment mechanism that adjusts the magnitude of the impact torque, thereby increasing the accuracy of the magnitude of the impact torque generated by the impact torque generating device of the hydraulic torque wrench and shortening the generation cycle of the impact torque (Patent Document 3).

[0006] 11 and 12 show an example of this hydraulic torque wrench. The wrench 1 is provided with a magnetostrictive torque detection mechanism 12, and the drive of the rotor 4 and the like are controlled by the output of this magnetostrictive torque detection mechanism 12. In this hydraulic torque wrench 1, the output adjustment mechanism 11 that adjusts the magnitude of the impact torque is configured to adjust the size of the hydraulic oil flow path 11b that communicates the interior of the liner 7, which becomes the high-pressure chamber H and the low-pressure chamber L when impact torque is generated, by operating the operating shaft 11a (specifically, by operating the operating shaft 11a to the open side and enlarging (not narrowing) the hydraulic oil flow path 11b, the magnitude of the impact torque decreases, and conversely, by operating the operating shaft 11a to the close side and narrowing (throttling) the hydraulic oil flow path 11b, the magnitude of the impact torque increases).

[0007] Furthermore, this output adjustment mechanism 11 is provided with a valve body 11d in the hydraulic oil flow path 11b, which is biased in the direction of opening the hydraulic oil flow path 11b via an operating shaft 11a and a spring 11c, and an oil chamber 11e is formed at the rear of this valve body 11d, which communicates with the inside of the liner 7, which becomes a high-pressure chamber H when impact torque is generated.As the pressure of the hydraulic oil in the high-pressure chamber H increases as the tightening operation progresses, an auto-relief mechanism is provided in which the hydraulic oil flow path 11b becomes smaller (throttled) in response to this increase in pressure of the hydraulic oil in the high-pressure chamber H, as shown in Figures 12(a) and 12(b).

[0008] This increases the accuracy of the magnitude of the impact torque generated by the impact torque generating device of the hydraulic torque wrench, shortens the impact torque generation cycle, and further improves the durability of the impact torque generating device of the hydraulic torque wrench.

[0009] Incidentally, the impact torque adjustment device of the hydraulic torque wrench 1 disclosed in Patent Document 3 provides the above-mentioned excellent operational effects, but it only functions in one direction of rotation, specifically, in forward rotation (tightening), and does not function in the other direction of rotation, specifically, in reverse rotation (loosening), and therefore does not provide the above-mentioned operational effects.

[0010] In order to address this problem, the applicant of the present application has proposed an impact torque adjusting device for a hydraulic torque wrench that increases the accuracy of the magnitude of the impact torque generated by the impact torque generating device of a hydraulic torque wrench during rotation in both directions, i.e., during forward rotation (tightening) and reverse rotation (loosening), shortens the impact torque generation cycle, and further improves the durability of the impact torque generating device of a hydraulic torque wrench (Patent Document 4).

[0011] Figures 13 and 14 show an example of this hydraulic torque wrench. The output adjustment mechanism 11 provided in this hydraulic torque wrench 1 adjusts the magnitude of the impact torque. The output adjustment mechanism 11 forms a hydraulic oil flow path 11b that communicates with the interior of the liner 7, which becomes the high-pressure chamber H and the low-pressure chamber L when impact torque is generated. A valve body 15d is disposed in the hydraulic oil flow path 11b and is biased in the direction of opening the hydraulic oil flow path 11b. An oil chamber 15e is formed behind the valve body 15d and communicates with the blade insertion portion 8a of the main shaft 8 via flow paths 7c and 7d formed in the liner lids 7a and 7b. The hydraulic oil flow path 11b becomes smaller in size in response to the increase in pressure of the hydraulic oil in the blade insertion portion 8a of the main shaft 8, which increases with the increase in pressure of the hydraulic oil in the high-pressure chamber H (the state shown in the upper part of Figure 14). An auto-relief mechanism 15 is provided.

[0012] The valve body 15d is made up of two valve bodies 15d arranged opposite each other with the hydraulic oil flow path 15b in between, and is biased by a spring 15c in a direction to open the hydraulic oil flow path 15b. Here, in order to stabilize the operation of the two valve bodies 15d, one valve body 15d (the valve body 15d on the right side in Figure 13(a)) is formed as a solid body, and the other valve body 15d (the valve body 15d on the left side in Figure 13(a)) is formed as a cylindrical body with a bottom, and a spring support / guide 15f is protruded from the solid valve body 15d on the right side to be inserted into the cylindrical portion of the left valve body 15d which is formed as a cylindrical body with a bottom.

[0013] The two valve bodies 15d are arranged opposite each other with the hydraulic oil flow path 11b in between, and an oil chamber 15e is formed at the rear of each valve body 15d, which is connected to the blade insertion portion 8a of the main shaft 8 via flow paths 7c, 7d formed in the liner upper cover 7a and lower cover 7b.In response to the increase in hydraulic oil pressure in the blade insertion portion 8a of the main shaft 8, which increases with the increase in hydraulic oil pressure in the high-pressure chamber H, the two valve bodies 15d move so that the hydraulic oil flow path 11b becomes smaller (throttled).

[0014] Incidentally, the impact torque adjustment devices for hydraulic torque wrenches disclosed in Patent Documents 3 and 4 have the above-mentioned excellent effects, but because springs 11c and 15c are used in the output adjustment mechanism 11 that adjusts the magnitude of the impact torque, there are problems with durability, and because there are restrictions on the size of the hydraulic oil flow path when it is open, it is difficult to achieve a sufficient improvement in energy efficiency, and furthermore, because the flow rate of the hydraulic oil is adjusted by the pressure of the hydraulic oil, there are problems with it being susceptible to fluctuations in the amount of oil.

[0015] In order to address this problem, the applicant of the present application has proposed an impact torque adjusting device for a hydraulic torque wrench (Patent Document 5) that has the advantages of the impact torque adjusting device for a hydraulic torque wrench disclosed in Patent Documents 3 and 4, such as high accuracy in the magnitude of the impact torque generated by the impact torque generating device of the hydraulic torque wrench and a short impact torque generation cycle, while also improving the durability and energy efficiency of the impact torque generating device of the hydraulic torque wrench and being less susceptible to fluctuations in the amount of oil.

[0016] Figures 1 to 3 show an example of this hydraulic torque wrench. Hydraulic torque wrench 1 has a cylinder section 14a formed in liner 7 parallel to the rotation axis, and a hydraulic oil flow path 14c that opens into cylinder section 14a and connects the inside of liner 7, which becomes a high-pressure chamber and a low-pressure chamber via cylinder section 14a when impact torque is generated, and is equipped with an auto-relief mechanism 14 in which a cylindrical valve body 14b having a cutout section 14b' formed in the circumferential surface thereof as a flow path for hydraulic oil is disposed so as to be freely rotatable within cylinder section 14a. The hydraulic torque wrench 1 also includes a magnetostrictive torque detection mechanism 12, and the drive of the rotor 4 and the like are controlled by the output of this magnetostrictive torque detection mechanism 12. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Japanese Utility Model Application Publication No. 3-40076 [Patent Document 2] Japanese Patent Application Publication No. 6-297349 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-83090 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-199790 [Patent Document 5] JP 2020-55081 A [Patent Document 6] Japanese Patent Application Publication No. 7-328944 [Patent Document 7] Japanese Patent Application Publication No. 2019-42919 [Patent Document 8] Japanese Patent Application Publication No. 2023-177373 Summary of the Invention [Problem to be solved by the invention]

[0018] The impact torque adjusting device for a hydraulic torque wrench disclosed in Patent Document 5 has the above-mentioned advantages, but the object of the present invention is to provide an impact torque adjusting device for a hydraulic torque wrench that is further improved to reduce the resistance of the hydraulic oil and shorten the tightening time, thereby improving tightening accuracy and energy efficiency. [Means for solving the problem]

[0019] In order to achieve the above object, the impact torque adjusting device of the hydraulic torque wrench of the present invention comprises: An impact torque adjusting device for a hydraulic torque wrench, comprising a liner rotated by a rotor, and a main shaft and blades disposed inside the liner, Two cylinder sections are formed in the liner parallel to the rotation axis at 180° symmetrical positions across the rotation axis, and hydraulic oil flow paths are formed that open into the cylinder sections and communicate the interiors of the liners, which become high-pressure chambers and low-pressure chambers when impact torque is generated, via the cylinder sections; a cylindrical valve element having a notch formed in a peripheral surface thereof to serve as a flow path for hydraulic oil is disposed in one of the two cylinder portions so as to be rotatable; a cylindrical valve body having a notch formed on its circumferential surface to serve as a flow path for hydraulic oil is rotatably disposed in the other of the two cylinder portions, and an operating shaft of an output adjustment mechanism is also disposed therein; The rotational position of the valve body within the cylinder portion is changed by the centrifugal force caused by the revolution of the valve body resulting from the rotation of the liner and the inertial force caused by the rotation of the valve body resulting from the sudden braking of the liner when a pulse is generated, By changing the rotational position of the valve body within the cylinder portion, the overlapping area between the opening of the hydraulic oil flow path in the cylinder portion and the notch in the valve body is changed, thereby adjusting the flow rate of hydraulic oil from the high-pressure chamber side to the low-pressure chamber side via the hydraulic oil flow path and the notch in the valve body. Equipped with an auto-relief mechanism It is characterized by:

[0020] In order to achieve the same object, the impact torque adjusting device of the hydraulic torque wrench of the present invention comprises: An impact torque adjusting device for a hydraulic torque wrench, comprising a liner rotated by a rotor, and a main shaft and blades disposed inside the liner, a cylinder portion is formed in the liner parallel to the rotation axis, and a hydraulic oil flow path is formed that opens to the cylinder portion and communicates the interior of the liner, which becomes a high-pressure chamber and a low-pressure chamber when an impact torque is generated, via the cylinder portion; a cylindrical valve element having two notches formed on its circumferential surface at 180° symmetrical positions and of different sizes to serve as flow paths for hydraulic oil, the valve element being rotatable within the cylinder; The rotational position of the valve body within the cylinder portion is changed by the centrifugal force caused by the revolution of the valve body resulting from the rotation of the liner and the inertial force caused by the rotation of the valve body resulting from the sudden braking of the liner when a pulse is generated, By changing the rotational position of the valve body within the cylinder portion, the overlapping area between the opening of the hydraulic oil flow path in the cylinder portion and the notch in the valve body is changed, thereby adjusting the flow rate of hydraulic oil from the high-pressure chamber side to the low-pressure chamber side via the hydraulic oil flow path and the notch in the valve body. Equipped with an auto-relief mechanism It is characterized by: [Effects of the Invention]

[0021] In addition to the above advantages of the impact torque adjusting device for a hydraulic torque wrench disclosed in Patent Document 5, the impact torque adjusting device for a hydraulic torque wrench of the present invention can be further improved to widen the hydraulic oil flow path (the passage area of ​​the hydraulic oil flow path when open), reduce the resistance of the hydraulic oil, allow the liner to rotate smoothly, and shorten the tightening time, thereby improving tightening accuracy and energy efficiency. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a front cross-sectional view of the entire structure showing a conventional impact torque adjusting device for a hydraulic torque wrench (Patent Document 5). [Figure 2] 4A to 4C are explanatory diagrams illustrating the operation of the impact torque adjusting device of the hydraulic torque wrench. [Figure 3]2A and 2B are explanatory views of the valve body of the impact torque adjusting device of the hydraulic torque wrench, in which (a) is an overall view, and (b) is a cross-sectional view taken along lines AA, BB, and CC in (a). [Figure 4] 1A and 1B show a first embodiment of an impact torque adjusting device for a hydraulic torque wrench according to the present invention, in which (a) is a cross-sectional view, (b) is a cross-sectional view of a main part (output adjusting mechanism), and (c) and (d) are explanatory diagrams of a valve body. [Figure 5] 4A to 4C are explanatory diagrams illustrating the operation of the impact torque adjusting device of the hydraulic torque wrench. [Figure 6] 10A and 10B are explanatory diagrams illustrating the operation of the valve body of the impact torque adjusting device of the hydraulic torque wrench. [Figure 7] 4 is a graph showing the relationship between the rotation angle of the valve element and the passage area of ​​the hydraulic oil flow path. FIG. [Figure 8] 1A and 1B show a first embodiment of an impact torque adjusting device for a hydraulic torque wrench according to the present invention, in which FIG. 1A is an explanatory diagram of the operation of a valve body, and FIG. 1B is an explanatory diagram of the valve body. [Figure 9] FIG. 1 is a front cross-sectional view showing an overall impact torque adjusting device for a conventional hydraulic torque wrench. [Figure 10] FIG. 1 is a front cross-sectional view showing an overall impact torque adjusting device for a conventional hydraulic torque wrench. [Figure 11] FIG. 1 is a front cross-sectional view showing an overall impact torque adjusting device for a conventional hydraulic torque wrench. [Figure 12] 1 is an explanatory diagram of the main parts of the impact torque adjustment device of the hydraulic torque wrench, where (a) is a front cross-sectional view of the main parts at the start of the tightening operation, (b) is a front cross-sectional view of the main parts as the tightening operation progresses, (c) is an AA cross-sectional view of (a), and (d) is a BB cross-sectional view of (a). [Figure 13] 1A and 1B show a conventional impact torque adjusting device for a hydraulic torque wrench, in which (a) is a front cross-sectional view, and (b) is an AA cross-sectional view of (a). [Figure 14] 4A to 4C are explanatory diagrams illustrating the operation of the impact torque adjusting device of the hydraulic torque wrench. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an impact torque adjusting device for a hydraulic torque wrench according to the present invention will now be described with reference to the accompanying drawings.

[0024] 4 to 7 show a first embodiment of an impact torque adjusting device for a hydraulic torque wrench according to the present invention.

[0025] This hydraulic torque wrench 1 uses an impact torque generating device, as previously proposed by the applicant in Patent Documents 6 to 8, in which the blades 9 are constantly urged by springs 10 toward the outer periphery of the main shaft 8 to abut against the inner periphery of the liner 7. Instead, the main shaft 8 is provided with two projections 8b, 8b with smooth surfaces, positioned at 180° rotational symmetry, and the liner 7 is formed with a hollow space defined by the projections 8b, 8b of the main shaft 8, into which two driving blades 16, 16 with smooth surfaces, approximately triangular in cross section, and the same size are fitted.

[0026] In this hydraulic torque wrench 1, two cylinder sections 14a, 11f are formed in the liner 7 parallel to the rotation axis at positions 180° symmetrical with respect to the rotation axis, and hydraulic oil flow paths 14c, 11b are formed which open to the cylinder sections 14a, 11f and communicate the interiors of the liners which become high-pressure chamber H and low-pressure chamber L when impact torque is generated via the cylinder sections 14a, 11f. A cylindrical valve body 14b having a notch 14b' formed on the circumferential surface thereof as a flow path for hydraulic oil is rotatably mounted in one of the cylinder sections 14a. In the other cylinder portion 11f, a cylindrical valve element 11g having a notched portion 11g' formed on its circumferential surface to serve as a flow path for hydraulic oil is disposed so as to be freely rotatable, and an operating shaft 11a of an output adjustment mechanism 11 is disposed therein, and the rotational positions of the valve elements 14b and 11g in the cylinder portion 14a are changed by the centrifugal force caused by the revolution of the valve elements 14b and 11g obtained from the rotation of the liner 7 and the inertial force caused by the rotation of the valve elements 14b and 11g obtained from the sudden braking of the liner 7 when a pulse is generated. Then, by changing the rotational position of the valve body 14b in the cylinder portions 14a and 11f, the overlapping area between the openings of the hydraulic oil flow paths 14c and 11b of the cylinder portions 14a and 11f and the notches 14b' and 11g' of the valve bodies 14b and 11g is changed, and the hydraulic oil flow paths 14c and 11b and the valves The valve is provided with an auto-relief mechanism 14 that adjusts the flow rate of hydraulic oil from the high pressure chamber H to the low pressure chamber L via the notches 14b', 11g' of the bodies 14b, 11g, and an output adjustment mechanism 11 that also functions as an auto-relief mechanism.

[0027] The valve bodies 14b, 11g used in this auto-relief mechanism 14 and the output adjustment mechanism 11 that also serves as an auto-relief mechanism have cutouts 14b', 11g' formed on the peripheral surface of the columnar material to serve as a flow path for hydraulic oil, so that their centers of gravity are offset from the central axis. As a result, when the liner 7 is rotating, the centrifugal force caused by the revolution of the valve bodies 14b, 11g resulting from the rotation of the liner 7 causes the rotation positions of the valve bodies 14b, 11g within the cylinder portions 14a, 11f to be positioned so that the notches 14b', 11g' of the valve bodies 14b, 11g face the center of the rotation axis of the liner 7 (the state shown in the lower part of Figure 5 and the 0° state in Figure 6).As a result, the overlapping area between the openings of the hydraulic oil flow paths 14c, 11b of the cylinder portions 14a, 11f and the notches 14b', 11g' of the valve bodies 14b, 11g becomes large, and the flow rate of hydraulic oil through the hydraulic oil flow paths 14c, 11b and the notches 14b', 11g' of the valve bodies 14b, 11g is not restricted. On the other hand, due to the inertial force caused by the rotation of the valve bodies 14b, 11g resulting from the sudden braking of the liner 7 when a pulse is generated, the rotational position of the valve bodies 14b, 11g within the cylinder portions 14a, 11f changes so that the notches 14b', 11g' of the valve bodies 14b, 11g face in a direction other than the center of the rotation axis of the liner 7 (the state shown in the upper part of Figure 5 (3. During pulse) and the 40° state in Figure 6).As a result, the overlapping area between the openings of the hydraulic oil flow paths 14c, 11b of the cylinder portions 14a, 11f and the notches 14b', 11g' of the valve bodies 14b, 11g becomes smaller (or substantially disappears), limiting the flow rate of hydraulic oil through the hydraulic oil flow paths 14c, 11b and the notches 14b', 11g' of the valve bodies 14b, 11g. The degree of restriction on the flow rate of this hydraulic oil varies depending on the magnitude of braking of the liner 7 when a pulse is generated, which increases the accuracy of the magnitude of the impact torque generated by the impact torque generating device of the hydraulic torque wrench, shortens the impact torque generation cycle, and improves work efficiency.

[0028] FIG. 7 shows the relationship between the rotation angle θ (0° to 40°) of the valve bodies 14b and 11g shown in FIG. 6 and the total passage area of ​​the hydraulic oil flow paths 14c and 11b for the present invention (embodiment) equipped with the auto-relief mechanism 14 and the output adjustment mechanism 11 that also functions as the auto-relief mechanism, and for a conventional example (comparison example) equipped with the auto-relief mechanism 14 and the output adjustment mechanism 11 that does not also function as the auto-relief mechanism. In the example, the total passage area is up to 24.4 mm 2 The passage area of ​​only the hydraulic oil passage 14c of the comparative example (maximum 12.2 mm 2 ) the passage area of ​​the hydraulic oil flow path is wider when open.

[0029] Furthermore, the valve bodies 14b and 11g made of a columnar material can have improved mechanical properties such as wear resistance by, for example, chrome plating the steel rod. Furthermore, both ends 14b" of the valve body 14b can be supported by steel balls 14d, and one end 11g" of the valve body 11g can be supported by a steel ball 11h biased by a spring 11i. This allows the valve bodies 14b and 11g to rotate smoothly.

[0030] Here, the output adjustment mechanism 11 is configured to adjust the size of the hydraulic oil flow path 11b, which connects the inside of the liner 7, which becomes the high-pressure chamber H and the low-pressure chamber L when the impact torque is generated, by operating the operating shaft 11a, which adjusts the magnitude of the impact torque (specifically, by operating the operating shaft 11a to the open side to enlarge (not narrow) the hydraulic oil flow path 11b, the magnitude of the impact torque decreases, and conversely, by operating the operating shaft 11a to the close side to narrow (narrow) the hydraulic oil flow path 11b, the magnitude of the impact torque increases).

[0031] Furthermore, this hydraulic torque wrench's impact torque adjustment device widens the hydraulic oil flow path (the passage area of ​​the hydraulic oil flow path when open) when rotating in both directions, i.e., when rotating forward (when tightening) and reverse (when loosening), reducing the resistance of the hydraulic oil and allowing the liner to rotate smoothly, thereby shortening the tightening time and improving tightening accuracy and energy efficiency. More specifically, the tightening time (when cut at 72 Nm) was 0.9 seconds for the present invention (Example) equipped with the auto-relief mechanism 14 and the output adjustment mechanism 11 that also functions as an auto-relief mechanism, which was 1.37 seconds for the conventional example (Comparative Example) equipped with the auto-relief mechanism 14 and the output adjustment mechanism 11 that does not also function as an auto-relief mechanism, and it was confirmed that the tightening time could be shortened by 35%. Furthermore, the tightening accuracy (±3Σ%) was 1.96% in the example, which was confirmed to be a 56% improvement over the comparative example's 4.51%.

[0032] In the first embodiment, the automatic relief mechanism 14 and the output adjustment mechanism 11 that also functions as an automatic relief mechanism are provided to widen the hydraulic oil flow path (the passage area of ​​the hydraulic oil flow path when open). However, as in a second embodiment of the impact torque adjustment device for a hydraulic torque wrench of the present invention shown in FIG. 8, by improving the valve body 14b of the automatic relief mechanism 14 of the impact torque adjustment device for a hydraulic torque wrench disclosed in Patent Document 5, it is possible to widen the hydraulic oil flow path (the passage area of ​​the hydraulic oil flow path when open), thereby achieving the same effect.

[0033] In this hydraulic torque wrench 1, a cylinder section 14a is formed in the liner 7 parallel to the rotation axis, and a hydraulic oil flow path 14c is formed that opens into the cylinder section 14a and connects the interior of the liner, which becomes a high-pressure chamber and a low-pressure chamber via the cylinder section 14a when an impact torque is generated, and a cylindrical valve element 14b, which has cutouts 14b1' and 14b2' formed on its circumferential surface to serve as flow paths for the hydraulic oil, is disposed so as to be free to rotate within the cylinder section 14a, and the rotational position of the valve element 14b within the cylinder section 14a changes due to the centrifugal force caused by the revolution of the valve element 14b resulting from the rotation of the liner 7 and the inertial force caused by the rotation of the valve element 14b resulting from the sudden braking of the liner 7 when a pulse is generated. The auto-relief mechanism 14 is provided which adjusts the flow rate of hydraulic oil from the high-pressure chamber H to the low-pressure chamber L via the hydraulic oil flow path 14c and the notches 14b1' and 14b2' of the valve body 14b by changing the rotational position of the valve body 14b within the cylinder portion 14a.

[0034] As shown in Figure 8(b), the valve body 14b used in this automatic relief mechanism 14 has two notches 14b1' and 14b2', which serve as flow paths for hydraulic oil, formed on the peripheral surface of a columnar material at 180° symmetrical positions with different sizes (notch lengths), so that its center of gravity is offset from the central axis. As a result, when the liner 7 is rotating, the centrifugal force caused by the revolution of the valve body 14b resulting from the rotation of the liner 7 causes the rotational position of the valve body 14b within the cylinder portion 14a to be positioned so that the cutouts 14b1' and 14b2' of the valve body 14b face toward the center of the rotation axis of the liner 7 (the 0° state in Figure 8(a)).This increases the overlap area between the opening of the hydraulic oil flow path 14c of the cylinder portion 14a and the cutouts 14b1' and 14b2' of the valve body 14b, and the flow rate of hydraulic oil through the hydraulic oil flow path 14c and the cutouts 14b1' and 14b2' of the valve body 14b is not restricted. On the other hand, due to the inertial force caused by the rotation of the valve element 14b resulting from the sudden braking of the liner 7 when a pulse is generated, the rotational position of the valve element 14b in the cylinder portion 14a changes so that the notches 14b1' and 14b2' of the valve element 14b face in a direction other than the center of the rotation axis of the liner 7 (the 40° state in FIG. 8(a)). As a result, the overlapping area between the opening of the hydraulic oil flow path 14c of the cylinder portion 14a and the notches 14b1' and 14b2' of the valve element 14b becomes smaller (or substantially eliminated). This restricts the flow rate of hydraulic oil through the hydraulic oil passage 14c and the notches 14b1' and 14b2' of the valve body 14b. The degree of restriction on the flow rate of this hydraulic oil varies depending on the magnitude of braking of the liner 7 when a pulse is generated, which increases the accuracy of the magnitude of the impact torque generated by the impact torque generating device of the hydraulic torque wrench, shortens the impact torque generation cycle, and improves work efficiency.

[0035] Other configurations and operations of this embodiment are the same as those of the impact torque adjusting device for a hydraulic torque wrench of the first embodiment.

[0036] The impact torque adjusting device for a hydraulic torque wrench of the present invention has been described above based on its embodiments, but the present invention is not limited to the configuration described in the above embodiments. For example, the impact torque generating device may be configured such that the blades 9 are constantly urged by the springs 10 toward the outer periphery of the main shaft 8 so as to abut against the inner periphery of the liner 7, or an electric motor may be used instead of the rotor 4 (air motor) which generates rotational torque by high-pressure air. The configuration can be modified as appropriate within the scope of the invention. [Industrial Applicability]

[0037] The impact torque adjustment device for a hydraulic torque wrench of the present invention has the characteristic of being able to reduce the resistance of the hydraulic oil in the impact torque generating device of the hydraulic torque wrench and shorten the tightening time, thereby improving tightening accuracy and energy efficiency, and therefore can be suitably used in hydraulic torque wrenches that use hydraulic impact torque generating devices. [Explanation of symbols]

[0038] 1 hydraulic torque wrench 2 Main Valve 3 Forward / reverse rotation switching valve 4 rotors 5. Impact torque generator 6 cases 7 Liner 7a Liner top cover 7b Liner bottom cover 7c flow path 7d Flow path 8 spindle 8a Blade insertion part 8b Protrusion 9 Feathers 10 Spring 11 Output adjustment mechanism 11a Operation axis 11b Hydraulic oil flow path (opening) 11c spring 11d Valve body 11e Oil room 11f Cylinder section 11g Valve body 11g' Notch 11g” end 11h steel ball 11i spring 12 Magnetostrictive torque detection mechanism 13 Shut-off valve mechanism 14 Auto-relief mechanism 14a Cylinder section 14b Valve body 14b', 14b1', 14b2' notch 14b” end 14c Hydraulic oil flow path (opening) 14d steel ball 15 Auto-relief mechanism 15b Hydraulic oil flow path 15c spring 15d Valve body 15e Oil room 15f Spring holder and guide B Relief valve H Hyperbaric chamber L Low pressure chamber

Claims

1. An impact torque adjusting device for a hydraulic torque wrench, comprising a liner rotated by a rotor, and a main shaft and blades disposed inside the liner, Two cylinder sections are formed in the liner parallel to the rotation axis at 180° symmetrical positions across the rotation axis, and hydraulic oil flow paths are formed that open into the cylinder sections and communicate the interiors of the liners, which become high-pressure chambers and low-pressure chambers when impact torque is generated, via the cylinder sections; a cylindrical valve element having a notch formed in a peripheral surface thereof to serve as a flow path for hydraulic oil is disposed in one of the two cylinder portions so as to be rotatable; a cylindrical valve body having a notch formed in a peripheral surface thereof to serve as a flow path for hydraulic oil, the valve body being rotatably disposed in the other of the two cylinder portions, and an operating shaft of an output adjustment mechanism is disposed therein; The rotational position of the valve body within the cylinder portion is changed by the centrifugal force caused by the revolution of the valve body resulting from the rotation of the liner and the inertial force caused by the rotation of the valve body resulting from the sudden braking of the liner when a pulse is generated, By changing the rotational position of the valve body within the cylinder portion, the overlapping area between the opening of the hydraulic oil flow path in the cylinder portion and the notch in the valve body is changed, thereby adjusting the flow rate of hydraulic oil from the high-pressure chamber side to the low-pressure chamber side via the hydraulic oil flow path and the notch in the valve body. Equipped with an auto-relief mechanism An impact torque adjusting device for a hydraulic torque wrench.

2. An impact torque adjusting device for a hydraulic torque wrench, comprising a liner rotated by a rotor, and a main shaft and blades disposed inside the liner, a cylinder portion is formed in the liner parallel to the rotation axis, and a hydraulic oil flow path is formed that opens to the cylinder portion and communicates the interior of the liner, which becomes a high-pressure chamber and a low-pressure chamber when an impact torque is generated, via the cylinder portion; a cylindrical valve element having two notches formed on its circumferential surface at 180° symmetrical positions and of different sizes to serve as flow paths for hydraulic oil, the valve element being rotatably disposed within the cylinder portion; The rotational position of the valve body within the cylinder portion is changed by the centrifugal force caused by the revolution of the valve body resulting from the rotation of the liner and the inertial force caused by the rotation of the valve body resulting from the sudden braking of the liner when a pulse is generated, By changing the rotational position of the valve body within the cylinder portion, the overlapping area between the opening of the hydraulic oil flow path in the cylinder portion and the notch in the valve body is changed, thereby adjusting the flow rate of hydraulic oil from the high-pressure chamber side to the low-pressure chamber side via the hydraulic oil flow path and the notch in the valve body. Equipped with an auto-relief mechanism An impact torque adjusting device for a hydraulic torque wrench.

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