A piston drive assembly for a hydraulic wrench and a hydraulic wrench

Abstract

The utility model discloses a piston drive assembly and hydraulic wrench for hydraulic wrench belongs to hydraulic wrench technical field, the utility model discloses a piston drive assembly includes piston body and driven rod, the piston body has the inner chamber of one end opening, the one end of driven rod is rotationally arranged in the inner chamber, the piston body includes the piston seat and sleeve of integrated molding, to cancel the connecting gap between both and need not to assemble sealing ring to can effectively reduce the risk that the sealing leaks appears at the junction. Meanwhile, the inner chamber includes the first cavity and the second cavity of intercommunication, wherein, the second cavity is used to accommodate the ball head portion of driven rod, and the hardness difference of ball head portion and second cavity inner wall is controlled in 5 10HRC. Such design, both guarantee the wear resistance of ball head portion self, avoid the excessive wear and tear of second cavity to ensure the stability of ball head portion in the rotation process, be favorable to the accurate transmission of driving force.

Description

Technical Field

[0001] This utility model belongs to the field of hydraulic wrench technology, and more specifically, relates to a piston drive assembly for a hydraulic wrench and a hydraulic wrench. Background Technology

[0002] A hydraulic torque wrench is a tool used to apply and control a predetermined torque, commonly used in mechanical assembly and maintenance. By precisely controlling the torque, it reduces errors caused by uneven torque application, ensuring that the torque of bolts or nuts reaches the predetermined value, thereby improving assembly quality and safety. Furthermore, by setting an appropriate torque value, it can prevent equipment damage or malfunction caused by over-tightening or loosening.

[0003] The basic working principle of a hydraulic wrench is that hydraulic oil, under the pressure of a hydraulic pump, enters the hydraulic cylinder. The piston inside the cylinder moves under the pressure of the fluid, generating torque. This torque is then transmitted to the bolt or nut via a transmission head, achieving the purpose of tightening or loosening. For example, existing patents disclose technologies such as CN213034505U - a balanced off-center load hydraulic wrench and CN104552098A - a hollow hydraulic wrench.

[0004] As can be seen from the basic working principle of a hydraulic wrench, the sealing performance of the piston is a crucial factor in ensuring the normal operation of the wrench. However, in existing hydraulic wrenches, hydraulic oil is prone to leakage after a period of operation, leading to insufficient pump pressure and thus affecting the normal use of the hydraulic wrench. Utility Model Content

[0005] The problem to be solved In view of at least some of the problems existing in the prior art, this utility model proposes a piston drive assembly for hydraulic wrenches, the purpose of which is to solve the problem that existing hydraulic wrench pistons are prone to leakage, resulting in pressure loss.

[0006] Technical solution To solve the above problems, the technical solution adopted by this utility model is as follows: The present invention provides a piston drive assembly for a hydraulic wrench, comprising a piston body and a driven rod; wherein the piston body has an inner cavity with one end open, and one end of the driven rod is rotatably disposed in the inner cavity, and the other end extends out of the inner cavity; The piston body is integrally formed; The driven rod includes a rod body portion and a ball head portion located at the end of the rod body portion; The internal cavity includes a first cavity and a second cavity that are interconnected; wherein, The first cavity is used to accommodate the rod portion, and the radial dimension of the first cavity is larger than the radial dimension of the rod portion, so that the rod portion can swing radially within the first cavity; The second cavity is used to accommodate the ball head portion, the hardness of which is greater than the hardness of the inner wall of the second cavity, and the hardness difference between the two is 5-10 HRC.

[0007] In some embodiments, the first cavity is generally conical, comprising at least a first segment and a second segment with gradually increasing cone angles; wherein the first segment is located on the opening side of the inner cavity; and the second segment is located between the first segment and the second cavity.

[0008] In some embodiments, the first cavity includes a first segment and a second segment that are interconnected; wherein the first segment is a tapered segment that connects to the opening side of the inner cavity, and the diameter near the opening end is larger than that at the other end; The second section is a straight cylindrical section, which is located between the first section and the second cavity.

[0009] In some implementations, the cone angle α of the first segment is 5-10°.

[0010] In some embodiments, the hardness of the ball head portion is HRC50-60, and the hardness of the inner wall of the second cavity is HRC45-50.

[0011] In some embodiments, the ball head portion is confined within the second cavity by a retaining ring, and the inner wall of the inner cavity is further provided with an inner ring groove for the retaining ring to be engaged.

[0012] In some embodiments, the piston body includes a piston seat and a sleeve connected to each other; wherein the second cavity is formed inside the piston seat, and the diameter of the piston seat is larger than the diameter of the sleeve.

[0013] In some embodiments, the end of the rod body away from the ball head portion is provided with a connecting portion, and the connecting portion has a connecting hole.

[0014] This utility model also provides a hydraulic wrench, including a hydraulic wrench body and a drive plate and a piston drive assembly disposed within the hydraulic wrench body; wherein, the piston drive assembly is the aforementioned piston drive assembly for a hydraulic wrench, and the end of the driven rod located outside the inner cavity is connected to the drive plate.

[0015] Beneficial effects Compared with the prior art, the beneficial effects of this utility model are as follows: (1) The piston drive assembly for a hydraulic wrench of this utility model has an integrated structure for the piston seat and the sleeve, eliminating the connection gap between the two and eliminating the need for a sealing ring, thereby effectively reducing the risk of sealing leakage at the connection and ensuring the normal use of the hydraulic wrench. At the same time, the hardness difference between the ball head and the inner wall of the second cavity is controlled within 5-10 HRC, and the hardness of the ball head is greater than that of the inner wall of the second cavity. This design not only ensures the wear resistance of the ball head itself, but also avoids excessive wear of the second cavity, thereby ensuring the stability of the ball head during rotation and facilitating the precise transmission of driving force.

[0016] (2) In a piston drive assembly for a hydraulic wrench of the present invention, the radial dimension of the first cavity is greater than the radial dimension of the rod part; at the same time, the cone angle of the first section is smaller than that of the second section; this design ensures that the rod part can swing freely in the first cavity to adapt to the arc-shaped movement trajectory of the end of the rod part; and also ensures the wall thickness of the second section as much as possible, which is conducive to ensuring the structural strength. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a piston drive assembly for a hydraulic wrench according to the present invention; Figure 2 This is an exploded view of a piston drive assembly for a hydraulic wrench according to the present invention. Figure 3 This is a schematic diagram of the internal structure of the piston body in this utility model; Figure 4 This is a schematic diagram showing the state of the driven rod during the working process in this utility model; Figure 5 This is a schematic diagram showing the connection between the driven rod and the drive plate of the hydraulic wrench in this utility model; Figure 6 This is a schematic diagram showing the rotation state of the drive plate during operation in this utility model.

[0018] In the diagram: 100, piston body; 110, piston seat; 111, outer ring groove; 120, sleeve; 130, inner cavity; 131. First cavity; 1311. First section; 1312. Second section; 1313. Inner annular groove; 132. Second cavity; 200. Driven rod; 210. Rod body; 220. Ball head; 230. Connecting part; 300, retaining ring; 400, drive board; 410, bayonet. Detailed Implementation

[0019] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings.

[0020] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] As described in the background section, existing hydraulic wrench pistons are prone to hydraulic oil leakage after a period of operation, thus affecting the normal output of pump pressure. The applicant discovered that hydraulic oil leakage often first occurs at the connection between the bushing and the piston body. This is because traditional hydraulic wrench pistons use a threaded connection with a sealing ring; that is, the bushing and piston body are connected by threads, and a sealing ring is used at the connection for sealing. However, after prolonged operation, slight loosening may occur at the threaded connection; at this time, the hydraulic oil under high pressure will leak. Therefore, the purpose of this utility model is to provide a solution that effectively prevents leakage at the connection between the bushing and the piston body, thereby extending the service life of the hydraulic wrench.

[0022] The present invention will be further described below with reference to specific embodiments.

[0023] like Figure 1 As shown, a piston drive assembly for a hydraulic wrench according to this embodiment includes a piston body 100 and a driven rod 200. Specifically, the piston body 100 has an inner cavity 130 with one end open, one end of the driven rod 200 is rotatably disposed in the inner cavity 130, and the other end extends out of the inner cavity 130.

[0024] like Figure 2 As shown, in some embodiments, the piston body 100 includes a piston seat 110 and a sleeve 120 connected to each other, and the piston seat 110 and the sleeve 120 are integrally formed. The driven rod 200 includes a rod body portion 210 and ball head portions 220 and connecting portions 230 located at both ends of the rod body portion 210; wherein, the ball head portion 220 is used for rotatably connecting with the inner cavity 130; the connecting portion 230 is used for connecting with the drive plate 400 of the hydraulic wrench.

[0025] Furthermore, such as Figure 3As shown, the inner cavity 130 includes a first cavity 131 and a second cavity 132 that are interconnected. The first cavity 131 is used to accommodate the rod portion 210, and the radial dimension of the first cavity 131 is larger than the radial dimension of the rod portion 210, so that the rod portion 210 can swing radially within the first cavity 131. The second cavity 132 is used to accommodate the ball head portion 220 and allows the ball head portion 220 to rotate.

[0026] Meanwhile, the second cavity 132 is formed inside the piston seat 110, and the radial dimension of the piston seat 110 is larger than the radial dimension of the sleeve 120. This is because the piston seat 110, as the main load-bearing component, is designed with larger dimensions to ensure its structural strength.

[0027] In other embodiments, the hardness of the ball head portion 220 is greater than the hardness of the inner wall of the second cavity 132, and the hardness difference between the two is 5-10 HRC, in order to prevent the ball head portion 220 or the inner wall of the second cavity 132 from being severely worn during operation, thereby increasing the wobbling space of the ball head portion 220 in the second cavity 132, reducing the fitting accuracy of the two, and being detrimental to the transmission of driving force.

[0028] Furthermore, the hardness of the ball head portion 220 is HRC50-60, for example, HRC52, HRC54, HRC56, HRC58, etc. The hardness of the inner wall of the second cavity 132 is HRC45-50, for example, HRC47, HRC48, HRC49, etc.

[0029] This embodiment provides a piston drive assembly for a hydraulic wrench. The piston seat 110 and sleeve 120 are integrated into a single structure, eliminating the connection gap and the need for a sealing ring. This effectively reduces the risk of sealing leakage at the connection point, ensuring the normal operation of the hydraulic wrench. Simultaneously, by controlling the hardness of the ball head portion 220 and the inner wall of the second cavity 132, both the wear resistance of the ball head portion 220 and excessive wear of the second cavity 132 are ensured, thereby guaranteeing the stability of the ball head portion 220 during rotation and facilitating precise transmission of driving force.

[0030] refer to Figure 5 , Figure 6 As shown, during operation, the hydraulic wrench's drive plate 400 engages with the nut to be tightened or loosened via its latch 410, while the nut remains stationary. Therefore, the drive plate 400 actually rotates around the center of the nut during operation. The movement path of the connection point P between the drive plate 400 and the driven rod 200 is arc M.

[0031] In other words, during operation, the driven rod 200 oscillates radially around the ball head portion 220. Therefore, the inner cavity 130 needs to provide a certain amount of oscillation space for the driven rod 200.

[0032] refer to Figure 3 , Figure 4 As shown, in this embodiment, the radial dimension of the first cavity 131 is larger than the radial dimension of the rod portion 210, so that the rod portion 210 can swing radially within the first cavity 131.

[0033] In some embodiments, the first cavity 131 is generally conical, comprising a first segment 1311 and a second segment 1312 that are interconnected. The first segment 1311 is located on the opening side of the inner cavity 130; the second segment 1312 is located between the first segment 1311 and the second cavity 132, and the cone angle of the first segment 1311 is smaller than that of the second segment 1312. This design ensures that the rod portion 210 can freely swing radially within the first cavity 131 to accommodate the arcuate movement trajectory of the end of the rod portion 210; it also maximizes the wall thickness of the second segment 1312, thereby contributing to structural strength.

[0034] Preferably, the cone angle α of the first segment 1311 is 5-10°, for example, 6°, 7°, 8°, etc.

[0035] In some other embodiments, the first cavity 131 includes a first segment 1311 and a second segment 1312 that are interconnected; wherein, the first segment 1311 is a conical segment that connects to the opening side of the inner cavity 130 and the diameter near the opening end is larger than the other end; the second segment 1312 is a straight cylindrical segment that is located between the first segment 1311 and the second cavity 132.

[0036] In this embodiment, the design of the straight section can further ensure the wall thickness of the second section 1312, so as to guarantee its structural strength.

[0037] This embodiment provides a piston drive assembly for a hydraulic wrench, referencing... Figure 2 , Figure 4 As shown, the ball head portion 220 is confined within the second cavity 132 by the retaining ring 300; of course, the inner wall of the inner cavity 130 needs to be provided with an inner ring groove 1313 for the retaining ring 300 to be engaged.

[0038] Meanwhile, an outer annular groove 111 for installing a sealing ring is provided on the outer peripheral wall of the piston seat 110. This sealing ring is used for sealing between the piston seat 110 and the cylinder.

[0039] refer to Figure 5As shown, this embodiment also provides a hydraulic wrench, which includes a hydraulic wrench body, a drive plate 400 and a piston drive assembly disposed within the hydraulic wrench body. The piston drive assembly is the aforementioned piston drive assembly for a hydraulic wrench, with the end of the driven rod 200 located outside the inner cavity 130 connected to the drive plate 400.

[0040] In this specific embodiment, the connecting part 230 is provided with a connecting hole, and a pin (not shown in the figure) is provided in the connecting hole for rotatably connecting with the drive plate 400.

[0041] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A piston drive assembly for a hydraulic wrench, comprising a piston body (100) and a driven rod (200); wherein, The piston body (100) has an inner cavity (130) with one end open, one end of the driven rod (200) is rotatably disposed in the inner cavity (130), and the other end extends out of the inner cavity (130); Its characteristic is that the piston body (100) is integrally formed; The driven rod (200) includes a rod body portion (210) and a ball head portion (220) located at the end of the rod body portion (210). The inner cavity (130) includes a first cavity (131) and a second cavity (132) that are interconnected; wherein, The first cavity (131) is used to accommodate the rod portion (210), and the radial dimension of the first cavity (131) is larger than the radial dimension of the rod portion (210) so that the rod portion (210) can swing radially within the first cavity (131); The second cavity (132) is used to accommodate the ball head portion (220), the hardness of which is greater than the hardness of the inner wall of the second cavity (132), and the hardness difference between the two is 5-10 HRC.

2. The piston drive assembly for a hydraulic wrench according to claim 1, characterized in that: The first cavity (131) is generally conical, and includes at least a first segment (1311) and a second segment (1312) with gradually increasing cone angles; wherein the first segment (1311) is located on the opening side of the inner cavity (130); the second segment (1312) is located between the first segment (1311) and the second cavity (132).

3. A piston drive assembly for a hydraulic wrench according to claim 1, characterized in that: The first cavity (131) includes a first segment (1311) and a second segment (1312) that are interconnected; wherein, the first segment (1311) is a conical segment that connects to the opening side of the inner cavity (130), and the diameter near the opening end is larger than that at the other end; The second section (1312) is a straight section, which is located between the first section (1311) and the second cavity (132).

4. A piston drive assembly for a hydraulic wrench according to claim 3, characterized in that: The cone angle α of the first segment (1311) is 5-10°.

5. A piston drive assembly for a hydraulic wrench according to any one of claims 1-4, characterized in that: The hardness of the ball head portion (220) is HRC50-60, and the hardness of the inner wall of the second cavity (132) is HRC45-50.

6. A piston drive assembly for a hydraulic wrench according to claim 5, characterized in that: The ball head portion (220) is confined within the second cavity (132) by a retaining ring (300), and the inner wall of the inner cavity (130) is also provided with an inner ring groove (1313) for the retaining ring (300) to be inserted.

7. A piston drive assembly for a hydraulic wrench according to claim 6, characterized in that: The piston body (100) includes a piston seat (110) and a sleeve (120) connected to each other; wherein the second cavity (132) is opened in the piston seat (110), and the diameter of the piston seat (110) is larger than the diameter of the sleeve (120).

8. A piston drive assembly for a hydraulic wrench according to claim 7, characterized in that: The end of the rod body (210) away from the ball head (220) is provided with a connecting part (230), and a connecting hole is provided on the connecting part (230).

9. A hydraulic wrench, comprising a hydraulic wrench body and a drive plate (400) and a piston drive assembly disposed within the hydraulic wrench body, characterized in that: The piston drive assembly is a piston drive assembly for a hydraulic wrench according to any one of claims 1-8, wherein the end of the driven rod (200) located outside the inner cavity (130) is connected to the drive plate (400).

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