Impact torque generator for hydraulic torque wrench

Abstract

To provide an impact torque generating device of a hydraulic torque wrench, that is compact and has a simplified structure.SOLUTION: An impact torque generating device of the hydraulic torque wrench is configured so that the number of driving blades 34 is one, and one impact torque is generated in a main shaft 9 per one rotation of a liner 31.SELECTED DRAWING: Figure 18

Description

Technical Field

[0001] The present invention relates to a striking torque generating device for a hydraulic torque wrench.

Background Art

[0002] As a striking torque generating device for a torque wrench, a hydraulic torque wrench using a hydraulic striking torque generating device with low noise and vibration has been developed and put into practical use. FIG. 20 shows an example of this hydraulic torque wrench. The main body 1 of this hydraulic torque wrench has a main valve 2 for supplying and stopping high-pressure air and a forward / reverse rotation switching valve 3 for selectively generating forward and reverse rotation striking torques. A rotor 4 that generates rotational torque is driven by the high-pressure air supplied from these valves 2 and 3. And a hydraulic striking torque generating device 5 that converts the rotational torque of the rotor 4 into a striking torque is provided in a front case 6 protruding from the tip of the main body 1 of the hydraulic torque wrench. This hydraulic striking torque generating device 5 has a liner 8 provided in a liner case 7, the liner 8 is filled and sealed with hydraulic oil, one or more blade insertion grooves are provided on a main shaft 9 coaxially inserted into the liner 8, a blade B is inserted into this blade insertion groove, and this blade B is constantly biased in the outer peripheral direction of the main shaft by a spring S and abuts against the inner peripheral surface of the liner 8, and one or more seal surfaces are formed on the outer peripheral surface of the main shaft 9. Further, an output adjustment mechanism 10 for adjusting the magnitude of the striking torque is provided on the liner 8. And when the plurality of seal surfaces formed on the inner peripheral surface of the liner 8, the seal surfaces formed on the outer peripheral surface of the main shaft 9, and the blade B coincide with each other by rotating the liner 8 by the rotor 4, a striking torque is generated on the main shaft 9.

[0003] In contrast to conventional hydraulic torque wrenches, the impact torque generating device employs a configuration in which a blade insertion groove is provided on the main shaft 9, a blade B is fitted into this groove, and the blade B is constantly biased in the outer direction of the main shaft by a spring S to contact the inner surface of the liner 8. As a result, there is a large energy loss due to the sliding resistance between the tip of the blade B and the inner surface of the liner 8, and the frictional heat generated by this sliding causes the temperature of the hydraulic fluid to rise, resulting in a change in the viscosity of the hydraulic fluid and a fluctuation in the output of the torque wrench. Furthermore, because it is necessary to provide a blade insertion groove and a hole for inserting the spring S on the main shaft 9, the diameter of the main shaft 9 must be increased in order to maintain the strength of the main shaft 9. Consequently, the device itself becomes larger and more complex in structure, and there are also problems with the durability of the device, such as breakage of the spring S.

[0004] To address this problem, the applicant previously proposed a hydraulic torque wrench impact torque generating device that eliminates the vanes B that are constantly biased in the outer direction of the main spindle by a spring S, thereby resulting in low sliding resistance, high energy efficiency, stable output with minimal rise in the temperature of the hydraulic fluid, and a compact, simple structure and high durability (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 Publication No. 2019-42919 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The basic structure of this hydraulic torque wrench is the same as that of a conventional hydraulic torque wrench shown in Figure 20. 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 and reverse rotation impact torque. The rotor 4, which generates rotational torque, is driven by high-pressure air supplied from 2 and 3. A hydraulic impact torque generator 5, which converts the rotational torque of the rotor 4 into impact torque, is installed in a front case 6 that protrudes from the tip of the main body 1 of the hydraulic torque wrench.

[0007] As shown in Figures 1 to 6, the hydraulic impact torque generating device 5 has a liner 11 inside a liner case 7, is filled with hydraulic fluid and sealed inside the liner 11, and has a main shaft 9 coaxially inserted inside the liner 11.

[0008] The liner 11 into which the main shaft 9 is inserted has a roughly elliptical cavity formed inside, and four sealing surfaces 11a and 11b are formed on its inner circumferential surface in a mountain shape in pairs. These pairs of sealing surfaces, i.e., sealing surface 11a and sealing surface 11b, are formed in positions that are 180° rotationally symmetrical. The cylindrical liner 11 is supported on its outer circumference by the liner case 7, and a liner upper cover 12 and a liner lower cover 13 are provided at both ends of the liner 11. The liner 11 and the liner upper cover 12 and liner lower cover 13 are configured to rotate as a single unit by inserting knock pins 17 into pin holes provided in the liner 11 and pin holes 12a and 13a provided in the liner upper cover 12 and liner lower cover 13, respectively. The liner upper cover 12 is further fixed axially by the liner case cover 7a to seal the hydraulic fluid filled inside the liner 11.

[0009] The main shaft 9, which is coaxially arranged inside the liner 11, has two protrusions 15a and 15b formed on its surface with a smooth shape, positioned at 180° rotationally symmetrical locations. The two protrusions 15a and 15b of the main shaft 9 are formed to have lengths shorter in both the axial and circumferential directions than the internal cavity of the liner 11, thereby creating passages for the flow of hydraulic fluid at both ends in the axial direction and at the tip in the circumferential direction.

[0010] Two driving blades 14a and 14b, both having a roughly triangular cross-section and the same size, with smooth surfaces, are fitted into a cavity formed inside the liner 11 and partitioned by projections 15a and 15b of the main shaft 9. The axial length of these two driving blades 14a and 14b is formed to be approximately the same as the length of the cavity inside the liner 11, so that the sides of the driving blades 14a and 14b slide against the inner surfaces of the liner upper cover 12 and the liner lower cover 13. Sealing surfaces corresponding to the sealing surfaces 11a and 11b of the liner 11 are formed near both ends, so that the sealing surfaces 11a and 11b of the liner 11 and the sealing surfaces of the driving blades 14a and 14b meet twice for each rotation of the liner 11.

[0011] The outer circumferential surface of the liner 11 is provided with communication grooves 16 that connect the cavities that form the low-pressure chambers L inside the liner 11, which are partitioned by the driving blades 14a, 14b and the sealing surfaces 11a, 11b of the liner 11.

[0012] Furthermore, the liner 11 is 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 one and consists of ports 10a and 10b that connect 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 separated by the driving blades 14a and 14b and the sealing surfaces 11a and 11b of the liner 11, and an output adjustment valve 10c that is adjustablely screwed into a screw hole 13b provided in the lower liner cover 13.

[0013] To explain the operation of the impact torque generating device 5 of this hydraulic torque wrench, first, by operating the main valve 2 and the switching valve 3, high-pressure air is introduced into the rotor chamber inside the main body 1, causing the rotor 4 to rotate at high speed. This rotational force of the rotor is transmitted to the liner 11.

[0014] As liner 11 rotates, the inside of liner case 7 moves as shown in Figure 6(a)→(b)→(c) The changes are as follows: →(d)→(a).... Figure 6(a) shows the state in which no impact torque is generated on the spindle 9, and (b), (c), and (d) show the state in which the liner 11 has rotated by approximately 90° from this point.

[0015] Impact torque is generated in the spindle 9 when shown in Figures 6(b) and (d), when the sealing surfaces 11a and 11b of the liner 11 and the sealing surfaces of the driving blades 14a and 14b coincide, the internal cavity of the liner 11 is divided into four chambers, and due to the shape of the internal cavity of the liner 11, at the moment impact torque is generated in the spindle 9, the volume on the high-pressure chamber H side decreases and the volume on the low-pressure chamber L side increases, so that each chamber becomes a high-pressure chamber H and a low-pressure chamber L. In other words, the rotor 4 rotates the liner 11, and when it reaches a position where the sealing surfaces 11a and 11b of the liner 11 and the sealing surfaces 14a and 14b of the driving blades 14a and 14b meet, the respective chambers become a high-pressure chamber H and a low-pressure chamber L. At the same time, the driving blades 14a and 14b are pushed towards the low-pressure chamber L, causing the sealing surfaces 11a and 11b of the liner 11 and the sealing surfaces 14a and 14b of the driving blades 14a and 14b to meet, completely sealing the internal cavity of the liner 11. The rotational force of the liner 11 acts on the projections 15a and 15b of the spindle 9 via the driving blades 14a and 14b, generating impact torque on the spindle 9. This impact torque, which is generated intermittently twice per rotation of the liner 11, rotates the spindle 9, allowing for desired operations such as tightening and loosening bolts and nuts.

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

[0017] Furthermore, when the rotor 4 is rotated in the reverse direction, the inside of the liner case 7 changes as shown in Figure 6(d)→(c)→(b)→(a)→(d)..., and it is possible to generate an impact torque on the spindle 9 in the opposite direction to before.

[0018] Here, the basic structure is the same as in the example above, but the hydraulic impact torque generating device 5 can also be configured as shown in Figures 7 to 12.

[0019] This hydraulic impact torque generating device 5 has a liner 21 inside a liner case 7, fills and seals the liner 21 with hydraulic fluid, and inserts the main shaft 9 coaxially into the liner 21.

[0020] The liner 21 into which the main shaft 9 is inserted has a roughly elliptical cavity formed inside, and four sealing surfaces 21a and 21b are formed on its inner circumferential surface in a mountain shape in pairs. These pairs of sealing surfaces, i.e., sealing surface 21a and sealing surface 21b, are formed in positions that are 180 degrees rotationally symmetrical. The cylindrical liner 21 is supported on its outer circumference by the liner case 7, and a liner upper cover 22 and a liner lower cover 23 are provided at both ends of the liner 21. The liner 21 and the liner upper cover 22 and liner lower cover 23 are configured to rotate as a single unit by inserting knock pins (not shown) into pin holes provided in the liner 21 and pin holes 22a and 23a provided in the liner upper cover 22 and liner lower cover 23, respectively. The liner upper cover 22 is further fixed axially by the liner case cover 7a to seal the hydraulic fluid filled inside the liner 21. Furthermore, guide grooves 22c and 23c are formed on the inner surfaces of the liner upper cover 22 and the liner lower cover 23, eccentrically with respect to the rotation axis O of the liner 21, such that the direction of eccentricity is 180 degrees rotationally symmetrical. In addition, a pin hole 23e and a hydraulic fluid injection hole 23f are formed in the liner lower cover 23. A pin hole 23e is provided that penetrates the liner case 7. By inserting part 28, the liner case 7 and the liner lower cover 23 are prevented from rotating.

[0021] The main shaft 9, which is coaxially arranged inside the liner 21, has two protrusions 25a and 25b formed on its surface with a smooth shape, positioned 180 degrees rotationally symmetrically. The two protrusions 25a and 25b on the main shaft 9 are formed to be shorter in both the axial and circumferential directions than the cavity inside the liner 21, thereby forming passages for the flow of hydraulic fluid at both ends in the axial direction and at the tip in the circumferential direction.

[0022] Two driving blades 24a and 24b, both having a smooth surface and a roughly triangular cross-section, are fitted into a cavity formed inside the liner 21 and partitioned by projections 25a and 25b of the main shaft 9. The axial length of these two driving blades 24a and 24b is formed to be approximately the same as the length of the cavity inside the liner 21, so that the sides of the driving blades 24a and 24b slide against the inner surfaces of the liner upper cover 22 and the liner lower cover 23. Sealing surfaces corresponding to the sealing surfaces 21a and 21b of the liner 21 are formed near both ends of the driving blades 24a and 24b. Pins 27a and 27b are formed on one side of the driving blades 24a and 24b, which are fitted into guide grooves 22c and 23c formed on the inner surfaces of the liner upper cover 22 and the liner lower cover 23. The pin 27b of the driving blade 24b is fitted into the guide groove 22c of the liner upper cover 22, and the guide groove of the liner lower cover 23 is fitted into the guide groove 23. The pins 27a of the driving blades 24a are fitted into 23c respectively, and when the sealing surfaces 21a and 21b of the liner 21 and the sealing surfaces 24a and 24b attempt to align twice per rotation of the liner 21, one of these attempts is prevented by restricting the movement of the driving blades 24a and 24b with the pins 27a and 27b of the driving blades 24a and 24b, which are fitted into guide grooves 22c and 23c formed eccentrically with respect to the rotation axis O of the liner 21 on the inner surfaces of the liner upper cover 22 and the liner lower cover 23, respectively. This configuration ensures that the spindle 9 generates a striking torque once per rotation of the liner 21.

[0023] On the outer peripheral surface of the liner 21, communication grooves 26 are provided that mutually communicate with cavity portions that serve as a low-pressure chamber L inside the liner 21, which are partitioned by the driving blades 24a and 24b and the seal surfaces 21a and 21b of the liner 21.

[0024] Also, an output adjustment mechanism 10 for adjusting the magnitude of the impact torque is provided in the liner 21 parallel to the axis of the liner 21. This output adjustment mechanism 10 is a conventionally well-known one, and is composed of ports 10a and 10b that communicate the cavity portion that serves as a high-pressure chamber H inside the liner 21 and the cavity portion that serves as a low-pressure chamber L, which are partitioned by the driving blades 24a and 24b and the seal surfaces 21a and 21b of the liner 21, and an output adjustment valve 10c that is adjusted from an operation hole 23b provided in the lower liner cover 23.

[0025] Also, an accumulator 29 for absorbing the 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 ventilation member 29b, and while one end surface of the piston 29a communicates with the cavity portion inside the liner 21 through an accumulator small hole 23d drilled in the lower liner cover 23, the other end surface is configured to communicate with the atmosphere through the ventilation member 29b, an accumulator small hole 22b drilled in the upper liner cover 22, and the gap between the upper liner cover 22 and the liner case cover 7a.

[0026] Regarding the operation of the impact torque generating device 5 of this hydraulic torque wrench, first, when high-pressure air is introduced into the rotor chamber in the main body 1 by operating the main valve 2 and the switching valve 3, the rotor 4 rotates at high speed. The rotational force of this rotor is transmitted to the liner 21.

[0027] Due to the rotation of the liner 21, the inside of the liner case 7 changes as shown in FIGS. 12(a) → (b) → (c ) → (d) → (a) ···. FIG. 12(a) shows a state where no impact torque is generated on the main shaft 9, and states where the liner 21 rotates by approximately 90 degrees from this are shown in (b), (c), and (d).

[0028] The impact torque is generated on the spindle 9 when shown in Figure 12(b), when the sealing surfaces 21a and 21b of the liner 21 and the sealing surfaces of the driving blades 24a and 24b coincide, the internal cavity of the liner 21 is divided into four chambers, and due to the shape of the internal cavity of the liner 21, at the moment the impact torque is generated on the spindle 9, the volume on the high-pressure chamber H side decreases and the volume on the low-pressure chamber L side increases, so that each chamber becomes a high-pressure chamber H and a low-pressure chamber L. In other words, the rotor 4 rotates the liner 21, and when it reaches a position where the sealing surfaces 21a and 21b of the liner 21 and the sealing surfaces 24a and 24b of the driving blades 24a and 24b meet, the respective chambers become a high-pressure chamber H and a low-pressure chamber L. At the same time, the driving blades 24a and 24b are pushed towards the low-pressure chamber L, causing the sealing surfaces 21a and 21b of the liner 21 and the sealing surfaces 24a and 24b of the driving blades 24a and 24b to meet, completely sealing the internal cavity of the liner 21. The rotational force of the liner 21 acts on the projections 25a and 25b of the spindle 9 via the driving blades 24a and 24b, generating impact torque on the spindle 9. This impact torque, which is generated intermittently once per rotation of the liner 21, rotates the spindle 9, allowing for desired operations such as tightening and loosening bolts and nuts.

[0029] On the other hand, as shown in Figure 12(d), the sealing surfaces 21a and 21b of the liner 21 and the sealing surfaces of the driving blades 24a and 24b attempt to align. However, at this time, the movement of the driving blades 24a and 24b is restricted by the pins 27a and 27b of the driving blades 24a and 24b, which are fitted into guide grooves 22c and 23c formed eccentrically with respect to 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 internal cavity of the liner 21 is not sealed, and therefore no impact torque is generated on the spindle 9.

[0030] Furthermore, as shown in Figures 12(a) and (c), when the sealing surfaces 21a and 21b of the liner 21 and the sealing surfaces 24a and 24b of the driving blades come into contact, the chambers will momentarily attempt to become a high-pressure chamber H and a low-pressure chamber L. However, because the driving blades 24a and 24b are pushed towards the low-pressure chamber L, the sealing surfaces 21a and 21b of the liner 21 and the sealing surfaces 24a and 24b of the driving blades do not come into contact. As a result, the internal cavity of the liner 21 is not sealed, and the hydraulic fluid from the high-pressure chamber H side flows through the gap between the two sealing surfaces to the low-pressure chamber L side, thus no impact torque is generated on the main shaft 9.

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

[0032] The hydraulic impact torque generator 5 shown in Figures 1 to 6 and Figures 7 to 12 does not require the vanes that are constantly biased in the outer direction of the main spindle by a spring, which were essential for the impact torque generator of the conventional hydraulic torque wrench shown in Figure 20. This provides advantages such as low sliding resistance, high energy efficiency, stable output with minimal temperature rise of the hydraulic fluid, and a compact, simple, and durable design for the impact torque generator of the hydraulic torque wrench.

[0033] The present invention aims to provide a hydraulic torque generator for a hydraulic torque wrench that is even smaller and simpler in structure, by further improving the hydraulic torque generator described in Figures 1 to 6 and 7 to 12, which has low sliding resistance, good energy efficiency, low temperature rise of the hydraulic fluid and stable output, is compact, has a simple structure and durability. [Means for solving the problem]

[0034] To achieve the above objective, the impact torque generating device of the hydraulic torque wrench of the present invention is A liner, which is rotated by a rotor, has a cavity filled with hydraulic fluid inside, and a sealing surface formed on the inner circumferential surface of the cavity, A main shaft having a protrusion and being coaxially arranged inside the liner, It has a driving blade that has sealing surfaces at both ends and is fitted into a cavity in a liner filled with hydraulic fluid, In a hydraulic torque wrench impact torque generating device that divides the inside of the liner into a high-pressure chamber and a low-pressure chamber by a driving blade to generate impact torque on the main shaft, The driving blade is characterized by having one blade and generating one impact torque on the main shaft for each rotation of the liner.

[0035] In this case, the liner can be provided with an output adjustment mechanism parallel to the axis of rotation, and the thickness of the liner on the opposite side of the output adjustment mechanism (180° range) can be made thinner than the thickness of the liner on the side of the output adjustment mechanism (180° range).

[0036] Furthermore, a cylinder portion is formed in the lid member of the liner parallel to the axis of rotation, and a hydraulic fluid passage is formed that opens into the cylinder portion and connects the inside of the liner, which becomes a high-pressure chamber and a low-pressure chamber when impact torque is generated, via the cylinder portion. A cylindrical valve body, having a notch formed on its circumferential surface to serve as a flow path for hydraulic fluid, is rotatably disposed within the cylinder portion. The rotational position of the valve body within the cylinder is changed by the centrifugal force due to the revolution of the valve body obtained from the rotation of the liner and the inertial force due to the rotation of the valve body obtained from the sudden braking of the liner when a pulse is generated. The rotational position of the valve body within the cylinder changes, thereby altering the overlapping area between the opening of the hydraulic fluid passage in the cylinder and the notch of the valve body, and adjusting the flow rate of hydraulic fluid from the high-pressure chamber to the low-pressure chamber through the hydraulic fluid passage and the notch of the valve body. It can be equipped with an auto-relief mechanism.

[0037] Furthermore, a protrusion can be formed at the point where the driving blade and the projection on the main shaft come into contact, such that the direction of the force generated by the contact between the driving blade and the projection on the main shaft is circumferential.

[0038] In this case, the protrusions can be formed at both ends of the projection on the main shaft. [Effects of the Invention]

[0039] The hydraulic torque wrench impact torque generating device of the present invention provides a smaller and simpler hydraulic torque wrench impact torque generating device by having only one driving blade and generating one impact torque on the main shaft for each rotation of the liner.

[0040] Furthermore, by providing an output adjustment mechanism parallel to the rotation axis in the liner, and by making the wall thickness of the liner on the opposite side of the output adjustment mechanism thinner than the wall thickness of the liner on the side of the output adjustment mechanism that is provided, it is possible to make the liner smaller (smaller in diameter) while ensuring sufficient hydraulic fluid capacity.

[0041] Furthermore, by incorporating an auto-relief mechanism into the liner cover member while maintaining the liner's small shape (small diameter), the accuracy of the magnitude of the impact torque generated by the impact torque generating device of the hydraulic torque wrench can be increased, and the impact torque generation cycle can be shortened. This improves the durability and energy efficiency of the impact torque generating device in a hydraulic torque wrench, and also makes it less susceptible to fluctuations in oil volume.

[0042] Furthermore, by forming a protrusion at the point where the driving blade and the projection of the main shaft come into contact, so that the direction of the force generated by the contact between the driving blade and the projection of the main shaft is circumferential, wear on the sealing surface of the inner circumferential surface of the driving blade and liner is greatly reduced, resulting in increased durability. In addition, since the force applied to the main shaft is applied over a long radial distance and at a near right angle, the output is increased, and combined with the low sliding resistance between the driving blade and the inner circumferential surface of the liner, energy efficiency can be further improved.

[0043] Furthermore, by forming protrusions at both ends of the projection on the main shaft, it is possible to accommodate rotation in both forward and reverse directions. [Brief explanation of the drawing]

[0044] [Figure 1] An example of a striking torque generating device for a hydraulic torque wrench is shown, with (a) being a front cross-sectional view and (b) being a second cross-sectional view thereof. [Figure 2] This figure shows the driving blade of the impact torque generating device in the same example. [Figure 3] This diagram shows the main shaft of the impact torque generating device in the same example. [Figure 4] This figure shows the liner top cover of the impact torque generating device in the same example. [Figure 5] This figure shows the lower liner cover of the impact torque generating device in the same example. [Figure 6] This figure shows the operating state of the impact torque generating device in the same example. [Figure 7] Another example of a striking torque generating device for a hydraulic torque wrench is shown, with (a) being a front cross-sectional view and (b) being a II-II cross-sectional view thereof. [Figure 8] This figure shows the driving blade of the impact torque generating device in the same example. [Figure 9] This diagram shows the main shaft of the impact torque generating device in the same example. [Figure 10] This figure shows the liner top cover of the impact torque generating device in the same example. [Figure 11]This figure shows the lower liner cover of the impact torque generating device in the same example. [Figure 12] This figure shows the operating state of the impact torque generating device in the same example. [Figure 13] This is a front cross-sectional view showing one embodiment of the impact torque generating device for a hydraulic torque wrench of the present invention. [Figure 14] The main shaft and driving blade of the impact torque generating device of the same embodiment are shown, (a1) is a front view of the main shaft, (a2) is a top view thereof, (a3) ​​is a right side view thereof, (b1) is a front view of the driving blade, (b2) is a right side view thereof, and (c) is a front view of the pin. [Figure 15] The liner upper cover of the impact torque generating device of the same embodiment is shown, (a1) is a front cross-sectional view of the outer member of the liner upper cover, (a2) is a front cross-sectional view of the inner member of the liner upper cover, (a3) ​​is a left side view thereof, (b1) is a front view of the retaining piece, and (b2) is a right side view thereof. [Figure 16] The liner and liner lower cover of the impact torque generating device of the same embodiment are shown, (a1) is a front cross-sectional view of the liner, (a2) is a central longitudinal cross-sectional view of the liner, (b1) is a front cross-sectional view of the liner lower cover, (b2) is a right side view thereof, (c1) is a front view of the valve body, (c2) is a right side view thereof, and (d) is a front view of the pin. [Figure 17] This figure shows the operating state of the impact torque generating device in the same embodiment. [Figure 18] This is an enlarged view showing the operating state of the impact torque generating device of the same embodiment. [Figure 19] This figure shows the operating state of the impact torque generating device in the same embodiment. [Figure 20] This diagram shows the overall structure of a hydraulic impact wrench incorporating a conventional impact torque generating device. [Modes for carrying out the invention]

[0045] Hereinafter, an embodiment of the impact torque generating device for the hydraulic torque wrench of the present invention will be described with reference to the drawings.

[0046] Figures 13 to 19 show an embodiment of the impact torque generating device for the hydraulic torque wrench of the present invention.

[0047] This hydraulic impact torque generator 5 is an improved version of the hydraulic impact torque generator 5 described in Figures 1 to 6 and Figures 7 to 12, making it smaller and simpler in structure.

[0048] The basic structure is the same as that of the hydraulic impact torque generating device 5 shown in Figures 1 to 6 and Figures 7 to 12, with a liner 31 provided inside the liner case 7, the liner 31 filled and sealed with hydraulic fluid, and the main shaft 9 fitted coaxially into the liner 31.

[0049] The liner 31 into which the main shaft 9 is inserted has a hollow section formed inside, and a single mountain-shaped sealing surface 31a is formed on its inner circumferential surface. The outer circumference of this cylindrical liner 31 is supported by the liner case 7, and a liner upper cover 32 (outer member 32a, inner member 32b) and a liner lower cover 33 are provided at both ends of the liner 31. The liner 31, the liner upper cover 32, and the liner lower cover 33 are configured to rotate as a single unit by inserting knock pins (not shown) into pin holes provided in the liner 31 and pin holes provided in the liner upper cover 32 and the liner lower cover 33, respectively. The liner upper cover 32 is further fixed axially by the liner case cover 7a to seal the hydraulic fluid filled inside the liner 31. In addition, a guide groove 32c is formed on the inner surface of the liner upper cover 32, eccentrically with respect to the rotation axis O of the liner 31. Here, the spindle 9 and the liner upper cover 32 (inner member 32b) are provided with fitting grooves 9a and 32d for the key 32e, which prevents the spindle 9 from coming loose.

[0050] Here, the hydraulic impact torque generating device 5 of this embodiment differs from the hydraulic impact torque generating device 5 described in Figures 1 to 6 and Figures 7 to 12 in that one of the pair of sealing surfaces 31a' is configured as the inner circumferential surface of the cavity. The inner circumferential surface of the cavity in the liner 31 that constitutes this sealing surface 31a' is formed in a substantially cylindrical shape. More specifically, the inner circumferential surface of the cavity in the liner 31 is composed of two cylindrical surfaces whose centers are offset to the outer circumferential side in the left-right direction, as shown in Figure 16(a2). In this way, by reducing the number of mountain-shaped sealing surfaces 31a to one, the machining process for the cavity in the liner 31 that forms the sealing surface 31a' can be effectively omitted, resulting in a simpler structure and providing a durable impact torque generating device for a hydraulic torque wrench. Furthermore, by providing an output adjustment mechanism 10 parallel to the rotation axis O at the position where the mountain-shaped sealing surface 31a of the liner 31 is formed, and by making the wall thickness of the liner on the opposite side of the output adjustment mechanism 10 thinner than the wall thickness of the liner on the side of the output adjustment mechanism 10 that is provided, it is possible to make the liner smaller (smaller diameter) while ensuring the amount of hydraulic fluid to be filled, thereby providing a compact, high-output hydraulic torque generating device.

[0051] The main shaft 9, which is coaxially arranged inside the liner 31, has two protrusions 35a and 35b formed on its surface with a smooth shape, positioned at 180° rotational symmetrical locations. The two protrusions 35a and 35b on the main shaft 9 are formed to be shorter in both the axial and circumferential directions than the cavity inside the liner 31, thereby forming passages for the flow of hydraulic fluid at both ends in the axial direction and at the tip in the circumferential direction.

[0052] Furthermore, protrusions 36a (36b) are formed on the protrusions 35a (35b) of the main shaft 9 that the driving blade 34 contacts, such that the direction of the force F1 generated when the driving blade 34 and the projection 35a of the main shaft 9 come into contact is approximately in the circumferential direction.

[0053] In this way, by forming a projection 36a(36b) on the projection 35a(35b) of the main shaft 9 that the driving blade 34 contacts, the direction of the force F1 generated when the driving blade 34 and the projection 35a(35b) of the main shaft 9 come into contact is approximately in the circumferential direction. As a result, wear on the inner circumferential surfaces (seal surfaces 31a, 31a') of the driving blade 34 and liner 31 is greatly reduced, resulting in increased durability. Furthermore, the force applied to the main shaft 9 is applied over a long radial distance and at a near-right angle, which increases the output. Combined with the low sliding resistance between the driving blade 34 and the inner circumferential surfaces (sealing surfaces 31a, 31a') of the liner 31, this allows for improved energy efficiency.

[0054] Furthermore, by forming protrusions 36a and 36b at both ends of the projections 35a and 35b of the main shaft 9, the above effects can be achieved regardless of whether the rotation is in the forward or reverse direction.

[0055] A single driving blade 34, with a roughly triangular cross-section and a smooth surface, is fitted into a cavity formed inside the liner 31 and partitioned by the projections 35a and 35b of the main shaft 9. The driving blade 34 is formed with an axial length approximately the same as the internal cavity of the liner 31, such that the side surface of the driving blade 34 slides against the inner surfaces of the liner upper cover 32 and the liner lower cover 33. Sealing surfaces corresponding to the sealing surfaces 31a and 31a' of the liner 31 are formed near both ends of the driving blade 34. A pin 37 is provided on the side surface of the driving blade 34, which is fitted into a guide groove 32c formed on the inner surface of the liner upper cover 32. By fitting the pin 37 of the driving blade 34 into the guide groove 32c of the liner upper cover 32, the sealing surfaces 31a and 31a' of the liner 31 and the sealing surface of the driving blade 34 align for each rotation of the liner 31, thereby generating a striking torque of one per rotation of the liner 31 on the spindle 9.

[0056] In this embodiment, instead of the pin inserted into the guide groove 32c that guides and restricts the movement of the driving blade 34, a steel ball (not shown) can also be used.

[0057] Furthermore, the liner 31 is 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 one and consists of a port (not shown) that connects a cavity that becomes a high-pressure chamber H and a cavity that becomes a low-pressure chamber L inside the liner 31, which are separated by the driving blade 24 and the sealing surfaces 31a and 31a' of the liner 31, and an output adjustment valve 10c that is adjusted from an operating hole 33b provided in the lower liner cover 33.

[0058] Furthermore, the lid member of the liner 31, specifically the lower liner lid 33, is equipped with an auto-relief mechanism 38. This auto-relief mechanism 38 has a cylinder portion 38a formed parallel to the axis of rotation, and a hydraulic fluid passage 38c that opens into the cylinder portion 38a and connects the inside of the liner, which becomes a high-pressure chamber H and a low-pressure chamber L when impact torque is generated, via the cylinder portion 38a. A cylindrical valve body 38b, which has a notch 38b' formed on its circumferential surface that serves as a hydraulic fluid passage, is rotatably disposed within the cylinder portion 38a, and the rotational position of the valve body 38b within the cylinder portion 38a is changed by the centrifugal force due to the revolution of the valve body 38b obtained from the rotation of the liner 31 (liner lower cover 33) and the inertial force due to the rotation of the valve body 38b obtained from the sudden braking of the liner 31 when a pulse is generated. Here, the valve body 38b is positioned in a predetermined location inside the liner lower cover 33 by a pin 38d. Furthermore, as the rotational position of the valve body 38b within the cylinder portion 38a changes, the overlapping area between the opening of the hydraulic fluid passage 38c in the cylinder portion 38a and the notch 38b' of the valve body 38b changes. This is done to adjust the flow rate of hydraulic fluid from the high-pressure chamber H side to the low-pressure chamber L side through the hydraulic fluid passage 38c and the notch 38b' of the valve body 38b.

[0059] As shown in Figures 16(c1) and (c2), the valve body 38b used in this auto-relief mechanism 38 has a notch 38b' formed on its circumferential surface that serves as a flow path for the hydraulic fluid, so that its center of gravity is offset from the central axis. As a result, when the liner 31 (liner lower cover 33) is rotating, the centrifugal force generated by the revolution of the valve body 38b resulting from the rotation of the liner 31 causes the rotational position of the valve body 38b within the cylinder portion 38a to be positioned such that the notch 38b' of the valve body 38b faces the center of the rotation axis of the liner 31 (as shown in Figures 16(c1) and (c2)). This increases the overlapping area between the opening of the hydraulic fluid passage 38c in the cylinder portion 38a and the notch 38b' of the valve body 38b, and the flow rate of hydraulic fluid through the hydraulic fluid passage 38c and the notch 38b' of the valve body 38b is not restricted. On the other hand, the rotational position of the valve body 38b within the cylinder portion 38a changes due to the inertial force of the valve body 38b resulting from the sudden braking of the liner 31 when a pulse is generated, such that the notch 38b' of the valve body 38b faces a direction other than the center of the rotation axis of the liner 31. As a result, the overlapping area between the opening of the hydraulic fluid passage 38c in the cylinder portion 38a and the notch 38b' of the valve body 38b becomes smaller (or virtually eliminated), thereby limiting the flow rate of hydraulic fluid through the hydraulic fluid passage 38c and the notch 38b' of the valve body 38b. The degree to which the flow rate of this hydraulic fluid is restricted changes depending on the magnitude of the braking of the liner 31 when a pulse is generated. Therefore, it is possible to increase the accuracy of the magnitude of the impact torque generated by the impact torque generator of the hydraulic torque wrench, shorten the impact torque generation cycle, and improve work efficiency.

[0060] Furthermore, the valve body 38b, which is made of a columnar material, can have its mechanical properties, such as wear resistance, improved by, for example, chrome plating. This allows the valve body 38b to rotate smoothly.

[0061] Furthermore, this hydraulic torque wrench's impact torque adjustment device can improve the accuracy of the magnitude of the impact torque generated by the hydraulic torque wrench's impact torque generator during unidirectional rotation, i.e., forward rotation (tightening), shorten the impact torque generation cycle, and further improve the durability of the hydraulic torque wrench's impact torque generator.

[0062] To explain the operation of the impact torque generating device 5 of this hydraulic torque wrench, first, by operating the main valve 2 and the switching valve 3, high-pressure air is introduced into the rotor chamber inside the main body 1, causing the rotor 4 to rotate at high speed. This rotational force of the rotor is transmitted to the liner 31.

[0063] As the liner 31 rotates, the inside of the liner case 7 changes as shown in Figure 17(a)→(b)→(c)→(d)→(a)...

[0064] Impact torque is generated in the spindle 9 when shown in Figures 17(c) and 18(c), when the sealing surfaces 31a and 31a' of the liner 31 meet the sealing surface of the driving blade 34, and the internal cavity of the liner 31 is divided into two chambers. Due to the shape of the internal cavity of the liner 31, at the moment impact torque is generated in the spindle 9, the volume of the high-pressure chamber H decreases and the volume of the low-pressure chamber L increases, so that each chamber becomes a high-pressure chamber H and a low-pressure chamber L. That is, when the rotor 4 rotates the liner 31 and it reaches a position where the sealing surfaces 31a and 31a' of the liner 31 meet the sealing surface of the driving blade 34, the chambers become a high-pressure chamber H and a low-pressure chamber L, and the driving blade 34 is pushed towards the low-pressure chamber L, so that the sealing surfaces 31a and 31a' of the liner 31 meet the sealing surface of the driving blade 34, the internal cavity of the liner 31 becomes completely sealed, and the rotational force of the liner 31 is applied to the driving blade The cord 34 acts on the projection 35a of the spindle 9, generating impact torque on the spindle 9. This impact torque, which is generated intermittently once per rotation of the liner 31, rotates the spindle 9, allowing for desired operations such as tightening and loosening bolts and nuts.

[0065] On the other hand, as shown in Figures 17(a), (b), and (d), the internal cavity of the liner 31 is not sealed, so no impact torque is generated on the spindle 9.

[0066] Furthermore, when the rotor 4 is rotated in the reverse direction, the inside of the liner case 7 changes as shown in Figure 19(a)→(b)→(c)→(d)→(a)... and when shown in Figure 19(c), a reverse impact torque can be generated on the spindle 9.

[0067] Furthermore, the other configurations and operations of this hydraulic impact torque generator 5 are the same as those of the hydraulic impact torque generator 5 described in Figures 1 to 6 and Figures 7 to 12.

[0068] The impact torque generating device for a hydraulic torque wrench of the present invention has been described above based on its embodiments. However, the present invention is not limited to the configuration described above. For example, an electric motor can be used as the drive source in addition to an air motor, and the configuration can be modified as appropriate without departing from the spirit of the invention. [Industrial applicability]

[0069] The impact torque generating device for the hydraulic torque wrench of the present invention does not require a vane that is constantly biased in the outer direction of the main spindle by a spring, has low sliding resistance and good energy efficiency, provides stable output with little temperature rise of the hydraulic fluid, is compact, has a simple structure and is durable, and can be suitably used in hydraulic torque wrenches using electric motors where the air cooling effect of the high-pressure air power source cannot be expected, and in hydraulic torque wrenches that require high tightening accuracy, as well as in applications such as hydraulic torque wrenches using air motors. [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 Liners 9 Main axis 10 Output adjustment mechanism 11 Liner 11a Sealing surface of the liner 11b Sealing surface of the liner 12 Liner top cover 13 Liner bottom cover 14a Driving Blade 14b Driving Blade 15a Projection of the main shaft 15b Projection of the main shaft 16 Communication groove 17 Knock pins 21 Liner 21a Sealing surface of the liner 21b Sealing surface of the liner 22 Liner top cover 22c guide groove 23 Liner lower cover 23c guide groove 24a Driving Blade 24b Driving Blade 25a Projection of the main shaft 25b Projection of the main shaft 26 Communication groove 27a pin 27b pin 29 Accumulator 31 Liner 31a Sealing surface of the liner 31a' Sealing surface of the liner 32 Liner top cover 32c guide groove 33 Liner lower cover 34 Driving Blades 35a Projection of the main shaft 35b Projection of the main shaft 36a Protruding part of the main shaft 36b Protrusion of the main shaft 37 pins 38 Auto-relief mechanism 38a Cylinder section 38b Valve body 38b' Notch 38c Hydraulic fluid passage 38d pin H High-pressure room L Low-pressure chamber S spring

Claims

1. A liner, which is rotated by a rotor, has a cavity filled with hydraulic fluid inside, and a sealing surface formed on the inner circumferential surface of the cavity, A main shaft having a protrusion and being coaxially arranged inside the liner, It has a driving blade that has sealing surfaces at both ends and is fitted into a cavity in a liner filled with hydraulic fluid, In a hydraulic torque wrench impact torque generating device that divides the inside of the liner into a high-pressure chamber and a low-pressure chamber by a driving blade to generate impact torque on the main shaft, A torque generating device for a hydraulic torque wrench, characterized in that the number of driving blades is one, and the device generates one impact torque on the main shaft for each rotation of the liner.

2. The impact torque generating device for a hydraulic torque wrench according to claim 1, characterized in that an output adjustment mechanism is provided on the liner parallel to the rotation axis, and the thickness of the liner on the opposite side of the output adjustment mechanism is made thinner than the thickness of the liner on the side of the output adjustment mechanism that is provided.

3. A cylinder portion is formed in the lid member of the liner parallel to the axis of rotation, and a hydraulic fluid passage is formed that opens into the cylinder portion and connects the inside of the liner, which becomes a high-pressure chamber and a low-pressure chamber when impact torque is generated, via the cylinder portion. A cylindrical valve body, having a notch formed on its circumferential surface to serve as a flow path for hydraulic fluid, is rotatably disposed within the cylinder portion. The rotational position of the valve body within the cylinder is changed by the centrifugal force due to the revolution of the valve body obtained from the rotation of the liner and the inertial force due to the rotation of the valve body obtained from the sudden braking of the liner when a pulse is generated. The rotational position of the valve body within the cylinder changes, thereby altering the overlapping area between the opening of the hydraulic fluid passage in the cylinder and the notch of the valve body, and adjusting the flow rate of hydraulic fluid from the high-pressure chamber to the low-pressure chamber through the hydraulic fluid passage and the notch of the valve body. It is now equipped with an auto-relief mechanism. The striking torque generating device for a hydraulic torque wrench according to claim 1 or 2.

4. The impact torque generating device for a hydraulic torque wrench according to claim 1 or 2, characterized in that a protrusion is formed at the point where the driving blade and the projection of the main shaft come into contact, such that the direction of the force generated by the contact between the driving blade and the projection of the main shaft is oriented in the circumferential direction.

5. The impact torque generating device for a hydraulic torque wrench according to claim 4, characterized in that the aforementioned protrusions are formed at both ends of the projection of the main shaft.

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