Liquid expansion inspection mandrel

Abstract

The application relates to a liquid expansion inspection mandrel which comprises a handle, a mandrel and a thin-wall expansion sleeve; the handle is coaxially sleeved at the rear end of the mandrel; the outer wall of the mandrel is provided with external threads; the inner wall of the handle is provided with internal threads; the handle and the mandrel are threadedly connected through cooperation of the external threads and the internal threads; the front end of the mandrel is in interference fit with the thin-wall expansion sleeve; an oil channel is formed in the mandrel and communicates with the inner cavity of the thin-wall expansion sleeve; a top pin piece and a hydraulic piston are arranged in the mandrel; the hydraulic piston slides in the oil channel along the axial direction of the mandrel; and the two ends of the top pin piece abut against the handle and the hydraulic piston respectively. When the handle is rotated, the handle drives the top pin piece to axially move through thread transmission, the top pin drives the hydraulic piston to extrude hydraulic oil in the oil channel, the hydraulic oil pressure is increased to drive the thin-wall expansion sleeve to uniformly expand in the radial direction, and part clamping is realized. The wrench is not needed to be additionally carried, the handle and the transmission structure are integrated, the mounting and dismounting steps are simplified, and the operation efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of liquid expansion mandrels, and in particular to a liquid expansion inspection mandrel. Background Technology

[0002] In scenarios such as gear inspection and part runout detection, the hydraulic expansion mandrel is a commonly used clamping and positioning component. Its core principle is to use the incompressibility of liquid to cause the thin-walled expansion sleeve to expand radially, thereby achieving precise clamping of the part.

[0003] In existing technology, the structure of a manual hydraulic expansion mandrel mainly includes a screw, a hydraulic piston, a closed cavity, and a thin-walled expansion sleeve. Its working process is as follows: The screw is rotated using an external wrench, which pushes the hydraulic piston to compress the liquid inside the closed cavity. The increased liquid pressure causes the thin-walled expansion sleeve to expand and clamp the parts. During disassembly, the screw is rotated in the opposite direction using a wrench to release the liquid pressure, and the thin-walled expansion sleeve returns to its original position due to its elasticity.

[0004] Each time parts are clamped or disassembled, external tools such as wrenches must be carried and operated, which not only increases the number of steps but also creates a cumbersome process for retrieving and storing tools, resulting in low clamping and disassembly efficiency. Utility Model Content

[0005] To address the issues of manual hydraulic mandrels relying on external tools, being cumbersome to operate, and being inefficient, this application provides a hydraulic inspection mandrel.

[0006] The hydraulic expansion testing mandrel provided in this application adopts the following technical solution: A hydraulic expansion test mandrel includes a handle, a mandrel, and a thin-walled expansion sleeve. The handle is coaxially sleeved at the rear end of the mandrel. The outer wall of the mandrel has an external thread, and the inner wall of the handle has an internal thread. The handle and the mandrel are connected by a mating external thread and an internal thread. The front end of the mandrel is interference-fitted with the thin-walled expansion sleeve. An oil passage is provided inside the mandrel, and the oil passage communicates with the inner cavity of the thin-walled expansion sleeve. A top pin and a hydraulic piston are provided inside the mandrel. The hydraulic piston slides in the oil passage along the axial direction of the mandrel. The two ends of the top pin abut against the handle and the hydraulic piston, respectively.

[0007] By adopting the above technical solution, when the handle is turned, the handle pushes the top pin to move axially through threaded transmission. The top pin pushes the hydraulic piston to squeeze the hydraulic oil in the oil circuit. The hydraulic oil pressure increases, driving the thin-walled expansion sleeve to expand radially and uniformly, thus clamping the parts. There is no need to carry an extra wrench. The integrated handle and transmission structure simplify the assembly and disassembly steps and improve operating efficiency. During assembly, only the top pin and hydraulic piston need to be installed into the mandrel in sequence, and then the handle is threadedly connected to the mandrel to ensure stable contact.

[0008] Preferably, the oil circuit includes a main oil passage and two branch passages. The branch passages penetrate the front end of the mandrel in the radial direction and are connected to the main oil passage. The inner cavity has two symmetrically arranged annular cavities in the axial direction. The two branch passages correspond to the two annular cavities respectively, and the two ends of the branch passages are connected to the corresponding annular cavities.

[0009] By adopting the above technical solution, hydraulic oil is delivered to the two annular cavities of the thin-walled expansion sleeve in separate channels, so that the expansion sleeve is uniformly expanded along the axial direction, avoiding uneven local expansion that could cause part positioning deviation, and better adapting to detection scenarios with high positioning accuracy requirements such as gears and precision parts.

[0010] Preferably, the oil circuit further includes an oil injection hole, which is arranged through the mandrel in the radial direction and communicates with the main oil passage. Both ends of the oil injection hole are respectively equipped with internal hexagon plugs.

[0011] By adopting the above technical solution, the oil injection hole facilitates subsequent replenishment or replacement of hydraulic oil, and the internal hexagon plug can achieve reliable sealing to prevent hydraulic oil leakage in the oil circuit. During assembly, after the internal structure of the mandrel is installed, an appropriate amount of hydraulic oil is injected through the oil injection hole, and then the plug is tightened. During maintenance, only the plug needs to be removed to complete the oil replenishment. The operation is convenient and does not damage the overall structure of the mandrel.

[0012] Preferably, the oil injection hole is located between the external thread and the thin-walled expansion sleeve. When the handle is rotated to completely cover the oil injection hole, the internal thread and the external thread are fully engaged; when the handle is rotated to completely disengage from the oil injection hole, the internal thread and the external thread are mostly disengaged.

[0013] By adopting the above technical solution, the handle can achieve the dual functions of blocking and protecting the oil injection hole and limiting the thread engagement: when fully engaged, the handle blocks the oil injection hole to prevent foreign objects from entering during inspection or clamping; when oiling is required, the handle is rotated to expose the oil injection hole, and at the same time, most of the thread disengages, preventing the handle from falling off due to excessive rotation; during assembly, the degree of thread engagement can be judged based on the blocking status of the oil injection hole, improving operational safety and convenience.

[0014] Preferably, the top pin includes a first top pin and a second top pin. The spindle has an oblong hole. The first top pin slides in the oblong hole along the axis of the spindle. One end of the second top pin is fixed to the hydraulic piston. The other end of the second top pin abuts against the first top pin. Both ends of the first top pin extend out of the spindle and abut against the handle.

[0015] By adopting the above technical solution, during assembly, the second top pin and hydraulic piston are installed first, and then the first top pin is installed. The oblong hole guides and limits the movement of the first top pin. At the same time, the first top pin can extend out of the spindle and abut against the handle. When the handle is turned, the handle pushes the first top pin to move. The first top pin drives the hydraulic piston to move through the second top pin. When resetting, the oil pressure inside the oil circuit will drive the hydraulic piston to reset.

[0016] Preferably, the length of the first pin is less than the diameter of the internal thread, and the handle has a stepped groove that matches the first pin, with both ends of the first pin abutting against the bottom wall of the stepped groove.

[0017] By adopting the above technical solution, the excessive length of the first top pin is avoided from interfering with the thread engagement. The stepped groove can accurately position the top pin abutment position, ensuring stable transmission of the pushing force when the handle is rotated. During assembly, simply align the two ends of the first top pin with the bottom wall of the stepped groove to achieve quick positioning and installation, reduce assembly errors, improve the stability of the fit between the top pin and the handle, and extend the service life of the spindle.

[0018] The main technical effects of this utility model are reflected in the following aspects: 1. When the handle of this utility model is rotated, the handle pushes the top pin to move axially through threaded transmission. The top pin pushes the hydraulic piston to squeeze the hydraulic oil in the oil circuit. The hydraulic oil pressure increases, driving the thin-walled expansion sleeve to expand radially and uniformly, thereby clamping the parts. No additional wrench is needed. The integrated handle and transmission structure simplify the assembly and disassembly steps and improve operating efficiency. During assembly, only the top pin and hydraulic piston need to be inserted into the mandrel in sequence, and then the handle is threadedly connected to the mandrel to ensure stable contact. 2. The oil filling hole of this utility model facilitates subsequent replenishment or replacement of hydraulic oil, and the internal hexagon plug can achieve reliable sealing to prevent hydraulic oil leakage in the oil circuit. During assembly, after the internal structure of the mandrel is installed, an appropriate amount of hydraulic oil is injected through the oil filling hole, and then the plug is tightened. During maintenance, only the plug needs to be removed to complete the oil replenishment. The operation is convenient and does not damage the overall structure of the mandrel. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the hydraulic expansion test mandrel in an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of the assembly of the handle and the spindle in an embodiment of this application.

[0021] Figure 3 It is along Figure 1 A cross-sectional view along line AA in the middle.

[0022] Explanation of reference numerals in the attached drawings: 1. Handle; 11. Internal thread; 12. Stepped groove; 2. Mandrel; 21. External thread; 22. Oil passage; 221. Main oil passage; 222. Branch passage; 223. Oil injection hole; 23. Hexagonal plug; 24. Waist-shaped hole; 3. Thin-walled expansion sleeve; 31. Inner cavity; 32. Annular cavity; 4. Top pin; 41. First top pin; 42. Second top pin; 5. Hydraulic piston. Detailed Implementation

[0023] The following is in conjunction with the appendix Figures 1-3 This application will be described in further detail to make the technical solution of this application easier to understand and master.

[0024] This application discloses a liquid expansion test mandrel.

[0025] Reference Figures 1-3 This embodiment of a hydraulic expansion test mandrel includes a handle 1, a mandrel 2, and a thin-walled expansion sleeve 3. The handle 1 is coaxially sleeved on the rear end of the mandrel 2. The outer wall of the mandrel 2 has an external thread 21, and the inner wall of the handle 1 has an internal thread 11. The handle 1 and the mandrel 2 are connected by the mating of the external thread 21 and the internal thread 11. The front end of the mandrel 2 is interference-fitted with the thin-walled expansion sleeve 3. An oil passage 22 is provided inside the mandrel 2, and the oil passage 22 is connected to the inner cavity 31 of the thin-walled expansion sleeve 3. A top pin 4 and a hydraulic piston 5 are provided inside the mandrel 2. The hydraulic piston 5 slides in the oil passage 22 along the axial direction of the mandrel 2. The two ends of the top pin 4 abut against the handle 1 and the hydraulic piston 5, respectively.

[0026] Reference Figures 1-3 When handle 1 is turned, handle 1 pushes the top pin 4 to move axially through threaded transmission. The top pin pushes the hydraulic piston 5 to squeeze the hydraulic oil in the oil circuit 22. The hydraulic oil pressure increases, driving the thin-walled expansion sleeve 3 to expand radially and uniformly, thus clamping the parts. No additional wrench is needed. The integrated handle 1 and transmission structure simplify the assembly and disassembly steps and improve operating efficiency. During assembly, only the top pin 4 and hydraulic piston 5 need to be inserted into the mandrel 2 in sequence, and then the handle 1 is threaded to the mandrel 2 to ensure stable contact.

[0027] Reference Figures 1-3 The oil passage 22 includes a main oil passage 221 and two branch passages 222. The branch passages 222 penetrate the front end of the mandrel 2 in the radial direction and are connected to the main oil passage 221. The inner cavity 31 has two symmetrically arranged annular cavities 32 in the axial direction. The two branch passages 222 correspond to the two annular cavities 32 respectively, and the two ends of the branch passages 222 are connected to the corresponding annular cavities 32.

[0028] Reference Figures 1-3 This allows hydraulic oil to be delivered to the two annular cavities 32 of the thin-walled expansion sleeve 3 in separate channels, so that the expansion sleeve is uniformly expanded along the axial direction, avoiding uneven local expansion that could cause part positioning deviation, and better adapting to detection scenarios with high positioning accuracy requirements such as gears and precision parts.

[0029] Reference Figures 1-3 The oil passage 22 also includes an oil injection hole 223, which is set through the spindle 2 in the radial direction and is connected to the main oil passage 221. An internal hexagon plug 23 is installed at both ends of the oil injection hole 223.

[0030] Reference Figures 1-3 The oil filling hole 223 facilitates the subsequent replenishment or replacement of hydraulic oil, and the internal hexagon plug 23 can achieve reliable sealing to prevent hydraulic oil leakage in the oil circuit 22. During assembly, after the internal structure of the spindle 2 is installed, an appropriate amount of hydraulic oil is injected through the oil filling hole 223, and then the plug is tightened. During maintenance, only the plug needs to be removed to complete the oil replenishment. The operation is convenient and does not damage the overall structure of the spindle 2.

[0031] Reference Figures 1-3 The oil injection hole 223 is located between the external thread 21 and the thin-walled expansion sleeve 3. When the handle 1 is rotated to completely cover the oil injection hole 223, the internal thread 11 and the external thread 21 are fully engaged. When the handle 1 is rotated to completely disengage from the oil injection hole 223, the internal thread 11 and the external thread 21 are mostly disengaged.

[0032] Reference Figures 1-3 The handle 1 serves a dual function: shielding the oil filling hole 223 and limiting the thread engagement. When fully engaged, the handle 1 shields the oil filling hole 223 to prevent foreign objects from entering during inspection or clamping. When oiling is required, the handle 1 is rotated to expose the oil filling hole 223, and most of the thread disengages, preventing the handle 1 from being over-rotated and falling off. During assembly, the degree of thread engagement can be judged based on the shielding status of the oil filling hole 223, improving operational safety and convenience.

[0033] Reference Figures 1-3 The top pin component 4 includes a first top pin 41 and a second top pin 42. A waist-shaped hole 24 is provided inside the spindle 2. The first top pin 41 slides in the waist-shaped hole 24 along the axial direction of the spindle 2. One end of the second top pin 42 is fixed to the hydraulic piston 5, and the other end of the second top pin 42 abuts against the first top pin 41. The second top pin 42 slides in the main oil passage 221 along with the hydraulic piston 5. Both ends of the first top pin 41 extend out of the spindle 2 and abut against the handle 1.

[0034] Reference Figures 1-3 During assembly, the second top pin 42 and the hydraulic piston 5 are installed first, and then the first top pin 41 is installed. The waist-shaped hole 24 guides and limits the movement of the first top pin 41. At the same time, the first top pin 41 can extend out of the spindle 2 and abut against the handle 1. When the handle 1 is turned, the handle 1 moves by pushing the first top pin 41. The first top pin 41 drives the hydraulic piston 5 to move through the second top pin 42. When resetting, the oil pressure inside the oil circuit 22 will drive the hydraulic piston 5 to reset.

[0035] Reference Figures 1-3 The length of the first top pin 41 is less than the diameter of the internal thread 11. The handle 1 has a stepped groove 12 that matches the first top pin 41. The two ends of the first top pin 41 abut against the bottom wall of the stepped groove 12.

[0036] Reference Figures 1-3 To avoid interference with the thread engagement due to excessive length of the first top pin 41, the stepped groove 12 can accurately position the top pin abutment position, ensuring stable transmission of the pushing force when the handle 1 rotates. During assembly, simply align the two ends of the first top pin 41 with the bottom wall of the stepped groove 12 to achieve quick positioning and installation, reduce assembly errors, improve the stability of the fit between the top pin 4 and the handle 1, and extend the service life of the spindle 2.

[0037] Of course, the above are just typical examples of this application. In addition, this application may have many other specific implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed in this application.

Claims

1. A hydraulically expanded inspection mandrel, characterized in that: The device includes a handle (1), a spindle (2), and a thin-walled expansion sleeve (3). The handle (1) is coaxially sleeved on the rear end of the spindle (2). The outer wall of the spindle (2) has an external thread (21), and the inner wall of the handle (1) has an internal thread (11). The handle (1) and the spindle (2) are connected by the mating threads of the external thread (21) and the internal thread (11). The front end of the spindle (2) is press-fitted with the thin-walled expansion sleeve (3). An oil passage (22) is provided inside the spindle (2). The oil passage (22) is connected to the inner cavity (31) of the thin-walled expansion sleeve (3). A top pin (4) and a hydraulic piston (5) are provided inside the spindle (2). The hydraulic piston (5) slides in the oil passage (22) along the axial direction of the spindle (2). The two ends of the top pin (4) abut against the handle (1) and the hydraulic piston (5), respectively.

2. The hydraulic expansion test mandrel according to claim 1, characterized in that: The oil passage (22) includes a main oil passage (221) and two branch passages (222). The branch passages (222) penetrate the front end of the mandrel (2) in the radial direction and are connected to the main oil passage (221). The inner cavity (31) has two symmetrically arranged annular cavities (32) in the axial direction. The two branch passages (222) correspond to the two annular cavities (32) respectively. The two ends of the branch passages (222) are connected to the corresponding annular cavities (32).

3. The hydraulic expansion test mandrel according to claim 2, characterized in that: The oil passage (22) also includes an oil injection hole (223), which is set through the mandrel (2) in the radial direction and is connected to the main oil passage (221). Both ends of the oil injection hole (223) are respectively equipped with internal hexagon plugs (23).

4. The hydraulic expansion test mandrel according to claim 3, characterized in that: The oil injection hole (223) is located between the external thread (21) and the thin-walled expansion sleeve (3). When the handle (1) is rotated to completely cover the oil injection hole (223), the internal thread (11) and the external thread (21) are fully engaged. When the handle (1) is rotated to completely disengage from the oil injection hole (223), the internal thread (11) and the external thread (21) are mostly disengaged.

5. The hydraulic expansion test mandrel according to claim 1, characterized in that: The top pin (4) includes a first top pin (41) and a second top pin (42). The spindle (2) has a waist-shaped hole (24). The first top pin (41) slides in the waist-shaped hole (24) along the axis of the spindle (2). One end of the second top pin (42) is fixed on the hydraulic piston (5). The other end of the second top pin (42) abuts against the first top pin (41). Both ends of the first top pin (41) extend out of the spindle (2) and abut against the handle (1).

6. The hydraulic expansion test mandrel according to claim 5, characterized in that: The length of the first top pin (41) is less than the diameter of the internal thread (11). The handle (1) has a stepped groove (12) that matches the first top pin (41). The two ends of the first top pin (41) abut against the bottom wall of the stepped groove (12).

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