Impact torque generator for hydraulic torque wrench

Abstract

To provide a striking torque generation device for a hydraulic torque wrench that has excellent durability and is improved in energy efficiency by reducing sliding resistance.SOLUTION: A striking torque generation device for a hydraulic torque wrench is formed with projection parts 36a, 36b in projection parts 35a, 35b of a spindle 9 on which driving blades 34a, 34b abut so as to orient a direction of force F1 generated when the driving blades 34a, 34b abut on the projection parts 35a, 35b of the spindle 9 in a circumferential direction.SELECTED DRAWING: Figure 14

Description

[Technical Field]

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

[0002] Hydraulic torque wrenches that use hydraulic impact torque generators that produce less noise and vibration as impact torque generators for torque wrenches have been developed and are now in practical use. Figure 17 shows an example of a hydraulic torque wrench. The hydraulic torque wrench's main body 1 includes a main valve 2 that switches the supply and stop of high-pressure air and a forward / reverse rotation switching valve 3 that selectively generates forward and reverse impact torque. The high-pressure air supplied through these valves 2 and 3 drives a rotor 4, which generates rotational torque. A hydraulic impact torque generator 5 that converts the rotational torque of the rotor 4 into impact torque is housed in a front case 6 protruding from the tip of the hydraulic torque wrench's main body 1. This hydraulic impact torque generator 5 includes a liner 8 housed within a liner case 7, which is filled and sealed with hydraulic oil. A main shaft 9 coaxially inserted within the liner 8 is provided with one or more blade insertion grooves, and blades B are inserted into the blade insertion grooves. The blades B are constantly biased toward the outer periphery of the main shaft by a spring S, abutting against the inner circumferential surface of the liner 8 and forming one or more sealing surfaces on the outer periphery of the main shaft 9. The liner 8 is also equipped with an output adjustment mechanism 10 that adjusts the magnitude of the impact torque. Then, by rotating the liner 8 with the rotor 4, when the multiple seal surfaces formed on the inner surface of the liner 8 come into contact with the seal surfaces formed on the outer surface of the main shaft 9 and the blades B, an impact torque is generated on the main shaft 9.

[0003] Incidentally, in the case of the impact torque generator of a conventional hydraulic torque wrench, one or more blade insertion grooves are provided in the main shaft 9, and blades B are inserted into these blade insertion grooves, and these blades B are constantly urged toward the outer periphery of the main shaft by springs S to abut against the inner circumferential surface of the liner 8. This has resulted in large energy loss due to sliding resistance between the tips of the blades B and the inner circumferential surface of the liner 8, and has also caused problems such as a rise in the temperature of the hydraulic oil due to frictional heat generated by this sliding, and changes in the viscosity of the hydraulic oil causing fluctuations in the output of the torque wrench. Furthermore, since it is necessary to provide holes in the main shaft 9 for inserting the blade insertion grooves and springs S, the diameter of the main shaft 9 must be increased in order to maintain the strength of the main shaft 9, which results in an increase in the size and complexity of the device itself, as well as problems with the durability of the device, such as damage to the springs S.

[0004] In order to address this problem, the applicant of the present invention previously proposed an impact torque generator for a hydraulic torque wrench that eliminates the blade B that is constantly biased toward the outer periphery of the spindle by a spring S, thereby reducing sliding resistance and improving energy efficiency, minimizing the temperature rise of the hydraulic oil, providing stable output, and being compact, simple in structure, and durable (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-328944 [Patent Document 2] Japanese Patent Application Publication No. 2019-42919 Summary of the Invention [Problem to be solved by the invention]

[0006] The basic structure of this hydraulic torque wrench is the same as that of the conventional hydraulic torque wrench shown in Figure 17. The hydraulic torque wrench has a main valve 2 that supplies and stops high-pressure air and a forward / reverse rotation switching valve 3 that selectively generates forward / reverse rotation impact torque. A rotor 4 that generates rotational torque is driven by high-pressure air sent from 2 and 3. A hydraulic impact torque generator 5 that converts the rotational torque of the rotor 4 into impact torque is provided inside a front case 6 that protrudes from the tip of the main body 1 of the hydraulic torque wrench.

[0007] As shown in FIGS. 1 to 6, the hydraulic impact torque generator 5 has a liner 11 provided in a liner case 7, the liner 11 filled with hydraulic oil and sealed, and the main shaft 9 inserted coaxially into the liner 11.

[0008] The liner 11, into which the main shaft 9 is inserted, has a generally elliptical cavity formed therein, and four pairs of seal surfaces 11a, 11b are formed in a mountain-like shape on its inner circumferential surface. These pairs of seal surfaces, i.e., seal surfaces 11a and 11b, are positioned at 180° rotational symmetry. The outer periphery of the cylindrical liner 11 is supported by the liner case 7, and an upper liner cover 12 and a lower liner cover 13 are disposed on both ends of the liner 11. The liner 11, the upper liner cover 12, and the lower liner cover 13 are configured to rotate integrally by inserting knock pins 17 into pin holes formed in the liner 11 and pin holes 12a, 13a formed in the upper liner cover 12 and the lower liner cover 13, respectively. The upper liner cover 12 is further fixed in the axial direction by the liner case cover 7a, sealing the hydraulic oil filled inside the liner 11.

[0009] The main shaft 9, which is coaxially disposed inside the liner 11, has two projections 15a and 15b, each having a smooth surface, formed at positions that are rotationally symmetrical by 180°. The two protrusions 15a, 15b of this main shaft 9 are configured so that their axial and circumferential lengths are both shorter than the hollow portion inside the liner 11, thereby forming passages through which hydraulic oil flows at both axial ends and the circumferential tip.

[0010] Two driving blades 14a, 14b of the same size and with a smooth surface and a roughly triangular cross section are inserted into a hollow formed inside liner 11 and partitioned by protrusions 15a, 15b of main shaft 9. The two driving blades 14a, 14b are formed with axial lengths that are approximately the same as the hollow inside liner 11 so that the side surfaces of driving blades 14a, 14b come into sliding contact with the inner surfaces of liner upper cover 12 and liner lower cover 13, and are formed with sealing surfaces near both ends that correspond to sealing surfaces 11a, 11b of liner 11, so that sealing surfaces 11a, 11b of liner 11 and the sealing surfaces of driving blades 14a, 14b come into contact twice per rotation of liner 11.

[0011] The outer peripheral surface of the liner 11 is provided with a communication groove 16 that interconnects the hollow portions that become the low-pressure chamber L inside the liner 11 defined by the driving blades 14a, 14b and the sealing surfaces 11a, 11b of the liner 11.

[0012] The liner 11 is also provided with an output adjustment mechanism 10 that adjusts the magnitude of the impact torque parallel to the axis of the liner 11. This output adjustment mechanism 10 is a conventionally known mechanism, and is composed of ports 10a and 10b that communicate between a cavity that becomes a high-pressure chamber H and a cavity that becomes a low-pressure chamber L inside the liner 11, which are partitioned by driving blades 14a and 14b and sealing surfaces 11a and 11b of the liner 11, and an output adjustment valve 10c that is adjustably screwed into a screw hole 13b provided in the liner bottom cover 13.

[0013] To explain the operation of the impact torque generator 5 of this hydraulic torque wrench, first, the main valve 2 and the switching valve 3 are operated to introduce high-pressure air into the rotor chamber in the main body 1, causing the rotor 4 to rotate at high speed. The rotational force of this rotor is transmitted to the liner 11.

[0014] As the liner 11 rotates, the inside of the liner case 7 flows in the order of FIG. 6(a)→(b)→(c). 6(a) shows a state in which no impact torque is generated in the main shaft 9, and (b), (c), and (d) show states in which the liner 11 rotates approximately 90° from this state.

[0015] Impact torque is generated in the main shaft 9 when, as shown in Figures 6(b) and (d), the sealing surfaces 11a and 11b of the liner 11 and the sealing surfaces of the driving blades 14a and 14b meet, and the cavity inside the liner 11 is divided into four chambers. Due to the shape of the cavity inside the liner 11, the moment impact torque is generated in the main shaft 9, the volume of the high-pressure chamber H side decreases and the volume of the low-pressure chamber L side increases, and each chamber becomes the high-pressure chamber H and the low-pressure chamber L. That is, when the rotor 4 rotates the liner 11 and the seal surfaces 11a, 11b of the liner 11 come into alignment with the seal surfaces of the driving blades 14a, 14b, the chambers become high-pressure chamber H and low-pressure chamber L, respectively, and the driving blades 14a, 14b are pushed toward the low-pressure chamber L, causing the seal surfaces 11a, 11b of the liner 11 to come into alignment with the seal surfaces of the driving blades 14a, 14b, completely sealing the cavity inside the liner 11, and the rotational force of the liner 11 acts on the protrusions 15a, 15b of the main shaft 9 via the driving blades 14a, 14b, generating an impact torque on the main shaft 9. The impact torque generated intermittently twice per rotation of the liner 11 rotates the main shaft 9, allowing the desired operation, such as tightening or loosening of bolts and nuts, to be performed.

[0016] On the other hand, as shown in Figures 6(a) and (c), when the sealing surfaces 11a, 11b of the liner 11 and the sealing surfaces of the driving blades 14a, 14b reach a position where they meet, the respective chambers instantly become a high-pressure chamber H and a low-pressure chamber L. However, because the driving blades 14a, 14b are pushed toward the low-pressure chamber L, the sealing surfaces 11a, 11b of the liner 11 and the sealing surfaces of the driving blades 14a, 14b do not meet, and the internal cavity of the liner 11 does not become sealed, so the hydraulic oil on the high-pressure chamber H side flows through the gap between the two sealing surfaces to the low-pressure chamber L side, and therefore no impact torque is generated in the main shaft 9.

[0017] Furthermore, when the rotor 4 is rotated in the reverse direction, the interior of the liner case 7 changes as shown in Figure 6(d) → (c) → (b) → (a) → (d) ..., and an impact torque can be generated in the main shaft 9 in the opposite direction to the previous one.

[0018] Here, although the basic structure is the same as the above example, the hydraulic impact torque generating device 5 can also be configured as shown in FIGS.

[0019] In this hydraulic impact torque generating device 5, a liner 21 is provided in a liner case 7, and the liner 21 is filled with hydraulic oil and sealed.

[0020] The liner 21, into which the main shaft 9 is inserted, has a generally elliptical cavity formed therein, and four pairs of seal surfaces 21a, 21b are formed in a mountain-like shape on its inner circumferential surface. These pairs of seal surfaces, i.e., seal surfaces 21a and 21b, are positioned at 180-degree rotational symmetry. The outer periphery of the cylindrical liner 21 is supported by the liner case 7, and an upper liner lid 22 and a lower liner lid 23 are disposed on both ends of the liner 21. The liner 21, the upper liner lid 22, and the lower liner lid 23 are configured to rotate integrally by inserting knock pins (not shown) into pin holes formed in the liner 21 and pin holes 22a, 23a formed in the upper liner lid 22 and the lower liner lid 23, respectively. The upper liner lid 22 is further fixed in the axial direction by the liner case lid 7a, sealing the hydraulic oil filled inside the liner 21. Furthermore, guide grooves 22c, 23c are formed on the inner surfaces of the liner upper cover 22 and the liner lower cover 23, eccentric to the rotation axis O of the liner 21, so that the eccentric directions are rotationally symmetrical by 180 degrees. Furthermore, a pin hole 23e and a hydraulic oil injection hole 23f are formed in the liner lower cover 23. The pin hole 23e is provided with a pin that penetrates the liner case 7. By fitting the bolt 28, the liner case 7 and the liner bottom cover 23 are prevented from rotating.

[0021] Two projections 25a, 25b with smooth surfaces are formed at positions that are 180 degrees rotationally symmetrical on the main shaft 9 that is coaxially disposed inside the liner 21. The two projections 25a, 25b on the main shaft 9 are formed so that their axial and circumferential lengths are both shorter than the hollow portion inside the liner 21, thereby forming passages through which the hydraulic oil flows at both ends in the axial direction and at the ends in the circumferential direction.

[0022] Two driving blades 24a, 24b of the same size and with a smooth surface and a roughly triangular cross section are inserted into a hollow formed inside the liner 21 and partitioned by the protrusions 25a, 25b of the main shaft 9. The two driving blades 24a, 24b are formed with axial lengths that are approximately the same as the hollow inside the liner 21 so that the side surfaces of the driving blades 24a, 24b come into sliding contact with the inner surfaces of the upper liner cover 22 and the lower liner cover 23. Sealing surfaces that correspond to the sealing surfaces 21a, 21b of the liner 21 are formed near both ends of the driving blades. Pins 27a, 27b that fit into guide grooves 22c, 23c formed on the inner surfaces of the upper liner cover 22 and the lower liner cover 23 are formed on one side of the driving blades 24a, 24b. The pin 27b of the driving blade 24b is inserted into the guide groove 22c of the upper liner cover 22, and the pin 27b of the driving blade 24b is inserted into the guide groove 22c of the lower liner cover 23. The pins 27a of the driving blade 24a are inserted into the guide grooves 22c, 23c formed on the inner surfaces of the liner upper cover 22 and the liner lower cover 23 eccentrically to the rotation axis O of the liner 21, and when the sealing surfaces 21a, 21b of the liner 21 and the sealing surfaces of the driving blades 24a, 24b attempt to mate twice per rotation of the liner 21, the movement of the driving blades 24a, 24b is restricted by the pins 27a, 27b of the driving blades 24a, 24b inserted into the guide grooves 22c, 23c formed on the inner surfaces of the liner upper cover 22 and the liner lower cover 23, respectively, to prevent the mating, thereby generating an impact torque on the main shaft 9 once per rotation of the liner 21.

[0023] The outer peripheral surface of the liner 21 is provided with a communication groove 26 that interconnects the hollow portions that become the low-pressure chamber L inside the liner 21 defined by the driving blades 24a, 24b and the sealing surfaces 21a, 21b of the liner 21.

[0024] The liner 21 is also provided with an output adjustment mechanism 10 that adjusts the magnitude of the impact torque parallel to the axis of the liner 21. This output adjustment mechanism 10 is a conventionally known mechanism, and is comprised of ports 10a and 10b that communicate between a cavity that becomes a high-pressure chamber H and a cavity that becomes a low-pressure chamber L inside the liner 21, which are partitioned by the driving blades 24a and 24b and the sealing surfaces 21a and 21b of the liner 21, and an output adjustment valve 10c that is adjusted through an operation hole 23b provided in the liner bottom cover 23.

[0025] Additionally, an accumulator 29 for absorbing thermal expansion of the hydraulic oil is provided in the liner 21 parallel to the axis of the liner 21. This accumulator 29 is composed of a piston 29a and a vent member 29b, and one end face of the piston 29a is connected to the hollow inside the liner 21 via a small accumulator hole 23d drilled in the liner bottom lid 23, while the other end face is connected to the atmosphere via the vent member 29b, the small accumulator hole 22b drilled in the liner top lid 22, and the gap between the liner top lid 22 and the liner case lid 7a.

[0026] To explain the operation of the impact torque generator 5 of this hydraulic torque wrench, first, the main valve 2 and the switching valve 3 are operated to introduce high-pressure air into the rotor chamber in the main body 1, causing the rotor 4 to rotate at high speed. The rotational force of this rotor is transmitted to the liner 21.

[0027] As the liner 21 rotates, the inside of the liner case 7 flows in the order of (a) → (b) → (c) of FIG. 12(a) shows a state in which no impact torque is generated in the main shaft 9, and (b), (c), and (d) show states in which the liner 21 rotates approximately 90 degrees from this state.

[0028] An impact torque is generated in the main shaft 9 when, as shown in Figure 12(b), the sealing surfaces 21a, 21b of the liner 21 and the sealing surfaces of the driving blades 24a, 24b meet, and the cavity inside the liner 21 is divided into four chambers. Due to the shape of the cavity inside the liner 21, the moment an impact torque is generated in the main shaft 9, the volume of the high-pressure chamber H side decreases and the volume of the low-pressure chamber L side increases, and each chamber becomes the high-pressure chamber H and the low-pressure chamber L, respectively. That is, when the rotor 4 rotates the liner 21 and the seal surfaces 21a, 21b of the liner 21 come into alignment with the seal surfaces of the driving blades 24a, 24b, the chambers become high-pressure chamber H and low-pressure chamber L, respectively, and the driving blades 24a, 24b are pushed toward the low-pressure chamber L, causing the seal surfaces 21a, 21b of the liner 21 to come into alignment with the seal surfaces of the driving blades 24a, 24b, completely sealing the cavity inside the liner 21, and the rotational force of the liner 21 acts on the protrusions 25a, 25b of the main shaft 9 via the driving blades 24a, 24b, generating an impact torque on the main shaft 9. The impact torque generated intermittently once per rotation of the liner 21 rotates the main shaft 9, allowing the desired operation, such as tightening or loosening of bolts and nuts, to be performed.

[0029] On the other hand, as shown in Figure 12(d), the sealing surfaces 21a, 21b of the liner 21 and the sealing surfaces of the driving blades 24a, 24b attempt to mate, but at this time the movement of the driving blades 24a, 24b is restricted by the pins 27a, 27b of the driving blades 24a, 24b inserted into the guide grooves 22c, 23c formed eccentrically with the rotation axis O of the liner 21 on the inner surfaces of the liner upper cover 22 and the liner lower cover 23. As a result, the hollow portion inside the liner 21 is not sealed, and no impact torque is generated in the main shaft 9.

[0030] 12(a) and 12(c), when the sealing surfaces 21a, 21b of the liner 21 and the sealing surfaces of the driving blades 24a, 24b reach a position where they meet, the respective chambers instantaneously become a high-pressure chamber H and a low-pressure chamber L, but because the driving blades 24a, 24b are pushed toward the low-pressure chamber L, the sealing surfaces 21a, 21b of the liner 21 and the sealing surfaces of the driving blades 24a, 24b do not meet, and the internal cavity of the liner 21 does not become sealed, so the hydraulic oil on the high-pressure chamber H side flows through the gap between the two sealing surfaces to the low-pressure chamber L side, and therefore no impact torque is generated in the main shaft 9.

[0031] Furthermore, when the rotor 4 is rotated in the reverse direction, the interior of the liner case 7 changes as shown in Figure 12(d) → (c) → (b) → (a) → (d) ..., and an impact torque can be generated in the main shaft 9 in the opposite direction to the previous one.

[0032] The hydraulic impact torque generator 5 shown in Figures 1 to 6 and Figures 7 to 12 does not require the blades that are constantly biased toward the outer periphery of the spindle by a spring, which was essential in the impact torque generator of the conventional hydraulic torque wrench shown in Figure 17, and has the advantages of being able to obtain an impact torque generator for a hydraulic torque wrench that has low sliding resistance, good energy efficiency, little temperature rise in the hydraulic oil, stable output, is small, has a simple structure, and is durable.

[0033] The present invention aims to provide an impact torque generator for a hydraulic torque wrench that is durable, has low sliding resistance, and is more energy efficient, has low temperature rise in the hydraulic oil, provides stable output, is small in size, has a simple structure, and is durable, by further improving the hydraulic impact torque generator 5 shown in Figures 1 to 6 and 7 to 12. [Means for solving the problem]

[0034] In order to achieve the above object, the impact torque generating device for a hydraulic torque wrench of the present invention comprises a liner rotated by a rotor, which has a hollow portion filled with hydraulic oil and which has a sealing surface formed so as to protrude from the inner peripheral surface of the hollow portion, a main shaft which has a protrusion and is disposed coaxially inside the liner, and a driving blade which has sealing surfaces on both ends and is inserted into the hollow portion of the liner which is filled with hydraulic oil, the driving blade dividing the inside of the liner into a high-pressure chamber and a low-pressure chamber, and the impact torque generating device for a hydraulic torque wrench is characterized in that a protrusion is formed on at least one of the positions where the driving blade and the protrusion of the main shaft come into contact so that the direction of the force generated by the contact between the driving blade and the protrusion of the main shaft is circumferential.

[0035] In this case, the protrusions can be formed on both circumferential sides of the protruding portion of the main shaft, or on both ends of the driving blade. [Effects of the Invention]

[0036] According to the impact torque generating device of the hydraulic torque wrench of the present invention, a protrusion is formed on at least one of the locations where the driving blade and the protrusion on the main shaft come into contact so that the direction of the force generated by the contact between the driving blade and the protrusion on the main shaft is circumferential, thereby significantly reducing wear on the inner surface of the driving blade and the liner and making them even more durable. In addition, the force applied to the main shaft is applied over a long radial distance and at a nearly right angle, which increases output and, combined with the low sliding resistance between the driving blade and the inner surface of the liner, improves energy efficiency.

[0037] Furthermore, by forming the protrusions on both circumferential sides of the protruding portion of the main shaft or on both ends of the driving blade, the above-mentioned effects can be achieved regardless of rotation in either the forward or reverse direction. [Brief explanation of the drawings]

[0038] [Figure 1] An example of an impact torque generating device for a hydraulic torque wrench is shown, where (a) is a front cross-sectional view and (b) is a cross-sectional view taken along line II. [Figure 2] FIG. 2 is a diagram showing a driving blade of the impact torque generating device of the same example. [Figure 3] FIG. 2 is a diagram showing a main shaft of the impact torque generating device of the same example. [Figure 4] FIG. 2 is a view showing a liner upper cover of the impact torque generating device of the same example. [Figure 5] FIG. 2 is a view showing a liner lower cover of the impact torque generating device of the same example. [Figure 6] 4A to 4C are diagrams illustrating the operation of the impact torque generating device of the same example. [Figure 7] 1 shows another example of an impact torque generating device for a hydraulic torque wrench, where (a) is a front cross-sectional view and (b) is a cross-sectional view taken along line II-II. [Figure 8] FIG. 2 is a diagram showing a driving blade of the impact torque generating device of the same example. [Figure 9] FIG. 2 is a diagram showing a main shaft of the impact torque generating device of the same example. [Figure 10] FIG. 2 is a view showing a liner upper cover of the impact torque generating device of the same example. [Figure 11] FIG. 2 is a view showing a liner lower cover of the impact torque generating device of the same example. [Figure 12] 4A to 4C are diagrams illustrating the operation of the impact torque generating device of the same example. [Figure 13] 1A and 1B show an embodiment of an impact torque generating device for a hydraulic torque wrench according to the present invention, in which FIG. 1A is a front cross-sectional view, and FIG. 1B is a cross-sectional view taken along the line III-III of FIG. [Figure 14] 5A and 5B are diagrams illustrating the operation of the impact torque generating device of the embodiment. [Figure 15] 13(a) and 13(b) are explanatory views of the same embodiment, where (a) corresponds to FIG. 13(b) and (b) is an enlarged view thereof. [Figure 16]1A and 1B are cross-sectional views of the protrusion of the spindle, in which (a) shows a conventional example, (b) shows an embodiment, and (c) shows another embodiment. [Figure 17] 1 is a diagram showing the entire hydraulic impact wrench incorporating a conventional impact torque generating device. DETAILED DESCRIPTION OF THE INVENTION

[0039] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an impact torque generating device for a hydraulic torque wrench according to the present invention will now be described with reference to the accompanying drawings.

[0040] 13 to 16 show an embodiment of an impact torque generating device for a hydraulic torque wrench according to the present invention.

[0041] This hydraulic impact torque generator 5 is a further improvement of the hydraulic impact torque generator 5 shown in Figures 1 to 6 and 7 to 12, and is more durable, has less sliding resistance, and has better energy efficiency.

[0042] The basic structure is the same as that of the hydraulic impact torque generating device 5 shown in Figures 1 to 6 and 7 to 12, with a liner 31 provided inside the liner case 7, which is filled with hydraulic oil and sealed, and the main shaft 9 being inserted coaxially into the liner 31.

[0043] The liner 31, into which the main shaft 9 is inserted, has a generally elliptical cavity formed therein, and two mountain-shaped seal surfaces 31a, 31b are formed on its inner circumferential surface at positions rotationally symmetrical by 180°. The outer periphery of this cylindrical liner 31 is supported by the liner case 7, and an upper liner lid 32 and a lower liner lid 33 are disposed at both ends of the liner 31. The liner 31, the upper liner lid 32, and the lower liner lid 33 are configured to rotate integrally by inserting knock pins (not shown) into pin holes formed in the liner 31 and pin holes formed in the upper liner lid 32 and the lower liner lid 33, respectively. The upper liner lid 32 is further fixed in the axial direction by the liner case lid 7a, sealing the hydraulic oil filled inside the liner 31. In addition, guide grooves 32c, 33c are formed on the inner surfaces of the upper liner lid 32 and the lower liner lid 33, eccentric to the rotation axis O of the liner 31, so that the eccentric directions are rotationally symmetrical by 180°. Furthermore, grooves for releasing hydraulic oil are formed at predetermined positions on the inner surfaces of the liner upper cover 32 and the liner lower cover 33.

[0044] Here, the hydraulic impact torque generator 5 of this embodiment differs from the hydraulic impact torque generator 5 shown in Figures 1 to 6 and 7 to 12 in that the other seal surface 31a', 31b' of the pair of seal surfaces 31a, 31b, i.e., the seal surface of the liner 31 corresponding to the seal surfaces of each driving blade 34a, 34b described below, is configured by the inner surface of the hollow portion. The inner peripheral surface of the hollow portion of the liner 31 that forms the sealing surfaces 31a' and 31b' has an approximately cylindrical shape, with an angle θ of 30° to 70°, preferably 40° to 60° (50° in this embodiment). As a result, by providing two mountain-shaped seal surfaces 31a, 31b, it is possible to substantially omit the process of machining the hollow portion of the liner 31 that forms these seal surfaces 31a', 31b', thereby providing an impact torque generating device for a hydraulic torque wrench that has a simple structure and is durable.

[0045] The main shaft 9, which is coaxially disposed inside the liner 31, has two projections 35a and 35b with smooth surfaces formed at positions that are rotationally symmetrical by 180°. The two projections 35a and 35b of the main shaft 9 have axial and circumferential lengths that are longer than the hollow portion inside the liner 31. By making each of the shafts shorter, a passage through which hydraulic oil flows is formed at both ends in the axial direction and at the end in the circumferential direction.

[0046] As shown in Figures 15 and 16, in this embodiment, protrusions 36a, 36b are formed on the protrusions 35a, 35b of the main shaft 9 with which the driving blades 34a, 34b come into contact so that the direction of the force F1 generated by the contact between the driving blades 34a, 34b and the protrusions 35a, 35b of the main shaft 9 is approximately circumferential.

[0047] Here, the directions of forces F1 and F2 generated by the contact between the driving blades 34a and 34b and the protrusions 35a and 35b of the main shaft 9 when protrusions 36a and 36b are formed on the protrusions 35a and 35b of the main shaft 9 (this embodiment) and when protrusions 36a and 36b are not formed (conventional example) are shown in Figure 15 by solid lines (this embodiment) and dashed lines (conventional example).

[0048] In this embodiment, protrusions 36a, 36b are formed on the protrusions 35a, 35b of the main shaft 9 with which the driving blades 34a, 34b come into contact so that the direction of the force F1 generated by the contact between the driving blades 34a, 34b and the protrusions 35a, 35b of the main shaft 9 is roughly circumferential. As a result, wear on the driving blades 34a, 34b and the inner surfaces of the liner 31 (sealing surfaces 31a, 31b, 31a', 31b') is significantly reduced, resulting in durability. Furthermore, in this embodiment, the radial distance L1 of the force applied to the main shaft 9 is longer than the radial distance L2 of the conventional example, and the force F1 is applied at a nearly right angle, which increases output and, combined with the small sliding resistance between the driving blades 34a, 34b and the inner surface of the liner 31, improves energy efficiency.

[0049] Table 1 shows the results of a comparative test conducted under the following test conditions for the case where protrusions 36a and 36b are formed on the protrusions 35a and 35b of the main shaft 9 (this embodiment) and the case where protrusions 36a and 36b are not formed (conventional example). [Test conditions] Testing machine: Uryu Seisakusho Co., Ltd. Tool tip spindle fixed type testing machine (UET-200BP) Drive power supply: DC18V

[0050] [Table 1]

[0051] As is clear from the results of the comparative test in Table 1, it was confirmed that when protrusions 36a, 36b are formed on the protrusions 35a, 35b of the main shaft 9 (this embodiment), both the output torque and the number of pulses are improved, and energy efficiency is improved, compared to when protrusions 36a, 36b are not formed (conventional example).

[0052] Furthermore, as shown in Figure 16(c), by forming protrusions 36a, 36b, 36a', 36b' on both circumferential surfaces of protrusions 35a, 35b of main shaft 9, the above-mentioned effects can be achieved in both forward and reverse rotation directions.

[0053] Two dry rollers of the same size and having a substantially triangular cross section with smooth surfaces are placed in a cavity formed inside the liner 31 and partitioned by the protrusions 35a and 35b of the main shaft 9. The two driving blades 34a, 34b are formed so that their axial lengths are approximately the same as the length of the hollow portion inside the liner 31 so that the side surfaces of the driving blades 34a, 34b are in sliding contact with the inner surfaces of the upper liner cover 32 and the lower liner cover 33, and seal surfaces corresponding to the seal surfaces 31a, 31a', 31b, 31b' of the liner 31 are formed near both ends thereof, and steel balls 37a, 37b are disposed on one side of the driving blades 34a, 34b to be inserted into guide grooves 32c, 33c formed on the inner surfaces of the upper liner cover 32 and the lower liner cover 33, and the steel balls 37b of the driving blade 34b are inserted into the guide groove 32c of the upper liner cover 32, and the steel balls 37b of the driving blade 34b are inserted into the guide groove 32c of the lower liner cover 33. The steel balls 37a of the driving blade 34a are fitted into the guide grooves 32c, 33c formed eccentrically with the rotation axis O of the liner 31 on the inner surfaces of the liner upper cover 32 and the liner lower cover 33, respectively, and when the sealing surfaces 31a, 31a', 31b, 31b' of the liner 31 and the sealing surfaces of the driving blades 34a, 34b attempt to meet twice per rotation of the liner 31, the steel balls 37a, 37b of the driving blades 34a, 34b are fitted into the guide grooves 32c, 33c formed eccentrically with the rotation axis O of the liner 31 on the inner surfaces of the liner upper cover 32 and the liner lower cover 33, respectively, to restrict the movement of the driving blades 34a, 34b, thereby preventing the meeting, and thereby generating an impact torque on the main shaft 9 once per rotation of the liner 31.

[0054] Here, instead of the steel balls 37a, 37b used in this embodiment that are inserted into guide grooves 32c, 33c to guide and regulate the movement of driving blades 34a, 34b, it is also possible to apply pins 27a, 27b that are inserted into guide grooves 22c, 23c that are used in hydraulic impact torque generator 5 shown in Figures 7 to 12 to guide and regulate the movement of driving blades 34a, 34b.

[0055] The outer peripheral surface of the liner 31 is provided with a communicating groove (not shown) that interconnects the hollow portions that form the low-pressure chamber L inside the liner 31, which are partitioned by the driving blades 34a, 34b and the sealing surfaces 31a, 31a', 31b, 31b' of the liner 31.

[0056] The liner 31 is also provided with an output adjustment mechanism 10 that adjusts the magnitude of the impact torque parallel to the axis of the liner 31. This output adjustment mechanism 10 is a conventionally known mechanism, and is comprised of a port (not shown) that communicates between a cavity that becomes the high-pressure chamber H inside the liner 31 and a cavity that becomes the low-pressure chamber L, which are partitioned by the driving blades 24a, 24b and the sealing surfaces 31a, 31a', 31b, 31b' of the liner 31, and an output adjustment valve 10c that is adjustably screwed into a threaded hole provided in the liner bottom cover 33.

[0057] The liner 31 is provided with an accumulator 39 parallel to the axis of the liner 31 for absorbing thermal expansion of the hydraulic oil.

[0058] To explain the operation of the impact torque generator 5 of this hydraulic torque wrench, first, the main valve 2 and the switching valve 3 are operated to introduce high-pressure air into the rotor chamber in the main body 1, causing the rotor 4 to rotate at high speed. The rotational force of this rotor is transmitted to the liner 31.

[0059] As the liner 31 rotates, the interior of the liner case 7 changes as shown in Figure 14(a) → (b) → (a)... Figure 14(a) shows a state in which impact torque is generated in the main shaft 9, and Figure 14(b) shows a state in which the liner 31 has rotated approximately 180° from this state.

[0060] The moment impact torque is generated on the main shaft 9, as shown in Figure 14(a), the seal surfaces 31a, 31a', 31b, 31b' of the liner 31 and the seal surfaces of the driving blades 34a, 34b meet, and the cavity inside the liner 31 is divided into four chambers. Due to the shape of the cavity inside the liner 31, the volume of the high pressure chamber H side decreases and the volume of the low pressure chamber L side increases, and each chamber becomes the high pressure chamber H and the low pressure chamber L. That is, the rotor 4 When the liner 31 reaches a position where the sealing surfaces 31a, 31a', 31b, and 31b' of the liner 31 mate with the sealing surfaces of the driving blades 34a and 34b, the chambers become high-pressure chamber H and low-pressure chamber L, respectively, and the driving blades 34a and 34b are pushed toward the low-pressure chamber L, causing the sealing surfaces 31a, 31a', 31b, and 31b' of the liner 31 to mate with the sealing surfaces of the driving blades 34a and 34b, completely sealing the cavity inside the liner 31. The rotational force of the liner 31 acts on the protrusions 35a and 35b of the main shaft 9 via the driving blades 34a and 34b, generating an impact torque on the main shaft 9. The impact torque generated intermittently once per rotation of the liner 31 rotates the main shaft 9, thereby performing the desired operation, such as tightening or loosening of bolts and nuts.

[0061] On the other hand, in the case shown in Figure 14(b), the sealing surfaces 31a, 31a', 31b, 31b' of the liner 31 and the sealing surfaces of the driving blades 34a, 34b attempt to mate, but at this time the movement of the driving blades 34a, 34b is restricted by the steel balls 37a, 37b of the driving blades 34a, 34b inserted into the guide grooves 32c, 33c formed eccentrically with respect to the rotation axis O of the liner 31 on the inner surfaces of the liner upper cover 32 and the liner lower cover 33. As a result, the hollow portion inside the liner 31 is not sealed, and no impact torque is generated in the main shaft 9.

[0062] In this way, the sealing surfaces 31a, 31a', 31b, and 31b' of the liner 31 and the sealing surfaces of the driving blades 34a and 34b never meet and form a seal except as shown in FIG. 14(a).

[0063] Furthermore, when the rotor 4 is rotated in the reverse direction, an impact torque in the reverse direction can be generated on the main shaft 9.

[0064] Other configurations and operations of this hydraulic impact torque generating device 5 are the same as those of the hydraulic impact torque generating device 5 shown in FIGS. 1 to 6 and 7 to 12.

[0065] Furthermore, as a mechanism for generating an impact torque on the main shaft 9 once per rotation of the liner 31, steel balls 37a, 37b that are inserted into guide grooves 32c, 33c and that guide and regulate the movement of the driving blades 34a, 34b, pins 27a, 27b that are inserted into guide grooves 22c, 23c and that are used in the hydraulic impact torque generator 5 shown in Figures 7 to 12 and that guide and regulate the movement of the driving blades 34a, 34b, as well as the mechanism disclosed in Patent Document 1 can be used.

[0066] Incidentally, since this hydraulic impact torque generating device 5 has low sliding resistance and good energy efficiency, it may be configured to generate impact torque on the main shaft 9 twice per rotation of the liner 31, similar to the hydraulic impact torque generating device 5 shown in Figures 1 to 6.

[0067] Furthermore, in this embodiment, protrusions 36a, 36b are formed on the protrusions 35a, 35b of the main shaft 9 with which the driving blades 34a, 34b come into contact so that the direction of the force F1 generated by the contact between the driving blades 34a, 34b and the protrusions 35a, 35b of the main shaft 9 is circumferential. However, the protrusions may be formed on the driving blades 34a, 34b side, or on both the protrusions 35a, 35b of the main shaft 9 and the driving blades 34a, 34b. When protrusions are formed on the driving blades 34a and 34b, the protrusions can be formed on both ends of the driving blades 34a and 34b, thereby enabling rotation in both forward and reverse directions.

[0068] The impact torque generating 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 configuration can be changed as appropriate within the scope of the invention, such as using an electric motor instead of an air motor as the driving motor. [Industrial Applicability]

[0069] The impact torque generating device for the hydraulic torque wrench of the present invention does not require blades that are constantly biased toward the outer periphery of the spindle by a spring, has low sliding resistance and good energy efficiency, produces stable output with little temperature rise of the hydraulic oil, is small in size, has a simple structure, and is durable. Therefore, it can be suitably used for hydraulic torque wrenches that use electric motors that cannot expect the air-cooling effect of high-pressure air as a power source, and hydraulic torque wrenches that require high tightening accuracy, and can also be used for hydraulic torque wrenches that use air motors, for example. [Explanation of symbols]

[0070] 1 Main unit 2 Main Valve 3 Forward / reverse rotation switching valve 4 rotors 5. Impact torque generator 6 Front case 7 Liner Case 8 Liner 9 Main axis 10 Output adjustment mechanism 11 Liner 11a Sealing surface of liner 11b Sealing surface of liner 12 Liner top cover 13 Liner bottom cover 14a driving blade 14b Driving Blade 15a Protrusion of the main shaft 15b Protrusion of the main shaft 16 Communication groove 17 Knock pin 21 Liner 21a Sealing surface of liner 21b Sealing surface of liner 22 Liner top cover 22c Guide groove 23 Liner bottom cover 23c Guide groove 24a driving blade 24b driving blade 25a Protrusion of the main shaft 25b Protrusion of the main shaft 26 Communication groove 27a pin 27b pin 29 Accumulator 31 Liner 31a Sealing surface of liner 31a' Sealing surface of liner 31b Sealing surface of liner 31b' Sealing surface of liner 32 Liner top cover 32c Guide groove 33 Liner bottom cover 33c Guide groove 34a driving blade 34b Driving Blade 35a Protrusion of the main shaft 35b Protrusion of the main shaft 36a Protruding part of the main shaft 36b Protruding part of the main shaft 36a' Projection of the main shaft protrusion 36b' Projection of the main shaft protrusion 37a steel ball 37b steel ball 39 Accumulator H Hyperbaric chamber L Low pressure chamber S spring

Claims

1. a liner that is rotated by the rotor and has a cavity filled with hydraulic oil and a seal surface that protrudes from the inner circumferential surface of the cavity; a main shaft having a protrusion and coaxially disposed inside the liner; two driving blades each having a substantially triangular cross section and each having a sealing surface at each end, the driving blade being inserted into a cavity of the liner filled with hydraulic oil; In a hydraulic torque wrench impact torque generating device, the inside of the liner is divided into a high-pressure chamber and a low-pressure chamber by a driving blade, and impact torque is generated in the main shaft. A protrusion is formed at the tip of the protrusion of the main shaft where the driving blade and the protrusion of the main shaft come into contact, so that the direction of the force generated by the contact between the driving blade and the protrusion of the main shaft is directed in the circumferential direction. An impact torque generating device for a hydraulic torque wrench.

2. 2. The impact torque generating device for a hydraulic torque wrench according to claim 1, wherein the protrusions are formed on both sides of the protruding portion of the main shaft in the circumferential direction.

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