Expandable mandrel for ensuring concentricity of inner circle and outer circle in stator processing

Abstract

The invention discloses an expandable mandrel for guaranteeing concentricity of an inner circle and an outer circle in stator machining, and belongs to the technical field of clamps. Comprising a positioning seat and a plurality of connecting assemblies, a supporting assembly is installed on the positioning seat, the connecting assemblies are connected end to end in an inserted mode or connected with the supporting assembly in an inserted mode, the supporting assembly comprises a fixing column, a second pressurizing hole and a second pressure relief hole are formed in the fixing column, a blocking channel is formed in the fixing column, and a blocking assembly is slidably installed in the blocking channel; the plugging assembly is inserted into the connecting assembly, and a plurality of pressurizing cavities are formed in the fixing column; a plurality of first core expanding blocks are installed on the supporting assembly and the connecting assembly, the first core expanding blocks are pulled and limited to the supporting assembly or the connecting assembly by pulling fourth elastic pieces, and pistons in sliding fit with the pressurizing cavities are installed on the first core expanding blocks. During pressurization, pressurization liquid pushes the multiple pistons to drive the corresponding first core expansion blocks to move, and the first core expansion blocks expand the inner diameter of a product.

Description

Technical Field

[0001] The invention relates to the technical field of clamps, and more specifically to an expandable core shaft for machining a stator to ensure the concentricity of inner and outer circles. Background Art

[0002] During stator processing, the stator is often supported by a support shaft that matches the inner diameter of the stator. However, during machining, welding or assembly processing, the stator may be heated, resulting in changes in the inner diameter, causing the support shaft and the stator to get stuck, making it more difficult to disengage. When point support is used, there is a risk that the stator slots of the stator will overlap with the support points, which will lead to unstable point support and the inability to accurately maintain the concentricity of the inner and outer circles. In view of this, we propose an expandable core shaft that can ensure the concentricity of the inner and outer circles during stator processing. Summary of the invention

[0003] The purpose of the present invention is to provide an expandable core shaft for ensuring the concentricity of inner and outer circles during stator machining, so as to solve the technical problems in the prior art that the stator is difficult to fix during machining and the concentricity of inner and outer circles cannot be accurately maintained.

[0004] The embodiment of the present invention provides an expandable mandrel for stator machining to ensure the concentricity of inner and outer circles, including a positioning seat and a plurality of connecting components, the positioning seat is provided with a first boosting hole and a first pressure relief hole connected to a boosting device, and a supporting component is installed on the positioning seat. The support assembly includes a fixing column mounted on a positioning seat, and a second pressure-increasing hole connected to the first pressure-increasing hole and a second pressure-relieving hole connected to the first pressure-relieving hole are formed on the fixing column. The fixed column is provided with a blocking channel connected with the second pressure-increasing hole and the second pressure-relief hole, and a blocking component for blocking the second pressure-increasing hole and the second pressure-relief hole is slidably installed in the blocking channel. A plurality of connecting components are plugged end to end or plugged with a supporting component and fixed on the connecting component through a plugging component, and two adjacent second boosting holes are connected after plugging; The fixed column is provided with a plurality of boosting chambers connected with the second boosting holes; A plurality of first core expansion blocks are slidably mounted on the support assembly and the connection assembly. The first core expansion blocks are limited on the support assembly or the connection assembly by pulling the fourth elastic member. A piston slidably matched with the boosting chamber is mounted on the first core expansion block. During pressurization, the pressurized liquid pushes a plurality of pistons to drive the corresponding first core expansion blocks to move, so that the first core expansion blocks expand the inner diameter of the product.

[0005] As a further description of the above technical solution, the blocking channel includes a first guide hole connected to the second pressure-increasing hole, the two ends of the first guide hole are respectively connected to the second guide hole and the third guide hole, and the third guide hole is connected to the second pressure-relief hole. The blocking assembly includes a first blocking block that slides with the first guide hole, the first blocking block is used to control the conduction of the second boost hole, one end of the first blocking block is fixedly connected to a guide column, and the other end is fixedly connected to a second blocking block, the guide column slides with the second guide hole, the second blocking block slides in the third guide hole, and is used to control the conduction of the second pressure relief hole, and the end of the guide column is rotatably connected to a screw that threads with the fixed column.

[0006] As a further description of the above technical solution, the height of the first blocking block is smaller than the height of the first guide hole.

[0007] As a further description of the above technical solution, the difference between the connecting assembly and the supporting assembly is that a third connecting hole connected to the second pressure-increasing hole and the second pressure-relief hole is provided on the fixing column of the connecting assembly, a fourth blocking block is slidably connected in the third connecting hole, a spacing is provided between the fourth blocking block and the bottom of the third connecting hole, a third elastic member for pulling the fourth blocking block is installed in the third connecting hole, and a plurality of leakage holes for connecting the third connecting hole and the second pressure-relief hole are provided on the fourth blocking block. A third blocking block is slidably fitted in the second pressurizing hole, and a second elastic member for pushing up the third blocking block is installed in the second pressurizing hole.

[0008] As a further description of the above technical solution, a positioning groove connected to the second boost hole is provided on the fixing column, and the positioning groove and the second boost hole are coaxial, and the second pressure relief hole is connected to the second boost hole through the second connecting hole and the connection is between the positioning groove and the first guide hole. A positioning column is fixedly installed at one end of the connecting component, and the positioning column is plugged into and matched with the corresponding positioning groove. The second boost hole passes through the positioning column and is connected to the previous second boost hole.

[0009] As a further description of the above technical solution, the fixing column is provided with a plurality of first limiting holes, and the first limiting holes are parallel to the axis of the fixing column. A plurality of second limiting columns are fixedly mounted on one end of the connecting assembly, and the second limiting columns are plugged into and matched with the corresponding first limiting holes. The guide column is provided with a through hole, in which a first limiting column is fixedly installed; the second limiting column is provided with a third limiting hole, in which the first limiting column is inserted, for limiting and fixing the second limiting column.

[0010] As a further description of the above technical solution, the fixed column is provided with a plurality of first connecting holes connected with the second boosting holes, a top block is slidably fitted in the first connecting hole, the end of the top block is inclined, and a first elastic member for pushing the top block is installed in the first connecting hole; The third blocking block is located between the first connecting hole and the first guide hole. A second limiting hole is formed on the second limiting column, and the top block is inserted into the second limiting hole to push the second limiting column to fix it; The end of the second pressure relief hole of the connecting assembly is blocked by a plug.

[0011] As a further description of the above technical solution, the elastic strength of the second elastic member is greater than the elastic strength of the first elastic member.

[0012] As a further description of the above technical solution, several of the first core expanding blocks are distributed in a circular array around the axis of the fixed column, the outer surface of the first core expanding block is an arc surface and the arc surface fits the inner diameter surface of the stator, and the arc length of the first core expanding block is greater than the stator slot width of the stator.

[0013] As a further description of the above technical solution, a second core expanding block is plugged into and fitted on the first core expanding block and fixed by fasteners, and the outer surface of the second core expanding block is an arc-shaped surface and fits with the corresponding inner diameter surface of the stator.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention enables the support component and the connecting component and the two groups of connecting components to be plugged into each other, and a first core expansion block is provided on both the support component and the connecting component, thereby achieving the change of the maximum support length of the first core expansion block, being able to adapt to the tightening of the inner diameter of the stator of different lengths, and improving the flexibility of stator fixation.

[0015] 2. When the piston of the first core expansion block of the present invention is subjected to hydraulic thrust, the outer surfaces of the first core expansion blocks are in contact with the inner diameter surface of the stator. When the hydraulic thrust is continuously provided, the first core expansion blocks tighten the inner diameter surface of the stator to fix the stator, thereby effectively ensuring the concentricity of the inner and outer circles during stator processing.

[0016] 3. The present invention blocks the second boost hole through a blocking component, thereby controlling the connection between two adjacent second boost holes. Moreover, when the connecting components are plugged into each other, the blocking component is also used to fix the connecting components, thereby maintaining the stability of the connection of the connecting components. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of an expandable mandrel for machining a stator to ensure the concentricity of the inner and outer circles disclosed in a preferred embodiment of the present invention; Figure 2 A cross-sectional view of an expandable mandrel for stator machining to ensure the concentricity of inner and outer circles disclosed in a preferred embodiment of the present invention; Figure 3 A schematic diagram of a fixed column structure of an expandable mandrel for ensuring the concentricity of inner and outer circles in a stator machining disclosed in a preferred embodiment of the present invention; Figure 4A method for machining a stator to ensure the concentricity of the inner and outer circles of the stator disclosed in a preferred embodiment of the present invention is to expand the core shaft Figure 2 Enlarged view of point A in the middle; Figure 5 A schematic structural diagram of a plugging assembly for an expandable mandrel for stator machining to ensure the concentricity of inner and outer circles disclosed in a preferred embodiment of the present invention; Figure 6 A schematic diagram of a connecting assembly structure of an expandable mandrel for machining a stator to ensure the concentricity of the inner and outer circles disclosed in a preferred embodiment of the present invention; Figure 7 A method for machining a stator to ensure the concentricity of the inner and outer circles of the stator disclosed in a preferred embodiment of the present invention is to expand the core shaft Figure 2 The enlarged structural diagram at B in the middle; Figure 8 A schematic diagram of a first core expansion block connection structure of a stator processing expandable core shaft for ensuring the concentricity of inner and outer circles disclosed in a preferred embodiment of the present invention; Fig. 9 A schematic diagram of the second core expansion block connection structure of an expandable core shaft for stator machining to ensure the concentricity of inner and outer circles disclosed in a preferred embodiment of the present invention.

[0018] Explanation of the numbers in the figure: 1. positioning seat; 2. supporting assembly; 3. connecting assembly; 4. first core expansion block; 5. guide rod; 6. fourth elastic member; 7. piston; 8. plugging groove; 9. second core expansion block; 10. plugging block; 11. first boost hole; 12. first pressure relief hole; 13. connecting nozzle; 14. threaded hole; 21. fixing column; 22. second boost hole; 23. second pressure relief hole; 24. boost chamber; 25. blocking channel; 26. blocking assembly; 27. first connecting hole; 28. top block; 29. ​​first elastic member; 31. third connecting hole; 32. first Four blocking blocks; 33, third elastic member; 34, leakage hole; 35, positioning column; 36, second limiting column; 37, second limiting hole; 38, third limiting hole; 39, plug; 210, third blocking block; 211, second elastic member; 212, second connecting hole; 213, positioning groove; 214, first limiting hole; 251, first guide hole; 252, second guide hole; 253, third guide hole; 261, first blocking block; 262, guide column; 263, second blocking block; 264, screw; 265, through hole; 266, first limiting column. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Reference Figures 1 to 9 A stator is processed to ensure the concentricity of the inner and outer circles and an expandable core shaft, comprising a positioning seat 1, on which a first pressure-increasing hole 11 and a first pressure-relieving hole 12 are opened, and a connecting nozzle 13 is installed at the mouth of the first pressure-increasing hole 11 and the first pressure-relieving hole 12. The first pressure-increasing hole 11 and the first pressure-relieving hole 12 are connected to a pressure-increasing device through a control valve, and the control valve is used to control the flow direction of the liquid when the pressure-increasing device is pressurized or relieved.

[0021] Reference Figures 1 to 7 A support assembly 2 is installed on the positioning seat 1, and the support assembly 2 includes a fixed column 21 fixedly installed on the positioning seat 1. The fixed column 21 is provided with a second pressurization hole 22 connected to the first pressurization hole 11 and a second pressure relief hole 23 connected to the first pressure relief hole 12. A plurality of pressurization chambers 24 connected to the second pressurization hole 22 are provided on the fixed column 21. The plurality of pressurization chambers 24 are distributed in a circular array around the axis of the fixed column 21. A blocking channel 25 is provided on the fixed column 21, and a blocking assembly 26 is slidably installed in the blocking channel 25.

[0022] The blocking channel 25 includes a first guide hole 251 connected to the second boost hole 22, and the two ends of the first guide hole 251 are respectively connected to the second guide hole 252 and the third guide hole 253, and the third guide hole 253 is connected to the second pressure relief hole 23. The blocking component 26 includes a first blocking block 261 that is slidably matched with the first guide hole 251. The height of the first blocking block 261 is less than the height of the first guide hole 251. The first blocking block 261 is used to control the conduction of the second boost hole 22. One end of the first blocking block 261 is fixed A guide column 262 is connected, and a second blocking block 263 is fixedly connected to the other end. The guide column 262 slides with the second guide hole 252, and the second blocking block 263 slides in the third guide hole 253 to control the conduction of the second pressure relief hole 23. The end of the guide column 262 is rotatably connected to a screw 264 that is threadedly engaged with the fixed column 21. A through hole 265 is opened on the guide column 262, and the opening direction of the through hole 265 is parallel to the axial direction of the fixed column 21. A first limiting column 266 is fixedly installed in the through hole 265.

[0023] A plurality of first connecting holes 27 connected to the second boosting hole 22 are provided on the fixed column 21, and a top block 28 is slidably fitted in the first connecting hole 27. The end of the top block 28 is inclined and has two opposite inclined surfaces. A first elastic member 29 for pushing the top block 28 is installed in the first connecting hole 27, and a third blocking block 210 is slidably fitted in the second boosting hole 22. The third blocking block 210 is located between the first connecting hole 27 and the first guide hole 251. A second elastic member 211 for pushing the third blocking block 210 is installed in the second boosting hole 22, and the elastic strength of the second elastic member 211 is greater than the elastic strength of the first elastic member 29.

[0024] The tail end of the second pressure relief hole 23 is connected with the second pressure boost hole 22 through the second connecting hole 212. A positioning groove 213 connected with the second pressure boost hole 22 is provided at the tail end of the fixed column 21, and the positioning groove 213 and the second pressure boost hole 22 are coaxial. The second connecting hole 212 is connected with the second pressure boost hole 22 between the positioning groove 213 and the first guide hole 251. A plurality of first limiting holes 214 connected with the first connecting hole 27 are provided on the fixed column 21. The first limiting hole 214 is parallel to the axis of the fixed column 21.

[0025] Reference Figure 4 and Figure 6 The expandable core shaft also includes a connecting component 3. The only difference between the connecting component 3 and the supporting component 2 is that a third connecting hole 31 connected to the second pressurizing hole 22 and the second pressure relief hole 23 is provided on the fixing column 21 of the connecting component 3. A fourth blocking block 32 is slidably connected in the third connecting hole 31. The fourth blocking block 32 does not contact the bottom of the third connecting hole 31, that is, there is a certain spacing. A third elastic member 33 for pulling the fourth blocking block 32 is installed in the third connecting hole 31. The fourth blocking block 32 is provided with a plurality of leakage holes 34 for connecting the third connecting hole 31 and the second pressure relief hole 23. A positioning column 35 and a plurality of second limiting columns 36 are fixedly installed at one end of the connecting component 3. The positioning column 35 is connected to the supporting component 2 Or the positioning groove 213 on the connecting component 3 is plugged in and matched, the second boost hole 22 passes through the positioning column 35 and is connected to the previous second boost hole 22, the second limiting column 36 is plugged in and matched with the corresponding first limiting hole 214, the second limiting column 36 is provided with a second limiting hole 37, the top block 28 is inserted into the second limiting hole 37 to push the second limiting column 36 to be stably fixed, a second limiting column 36 is provided with a third limiting hole 38, the first limiting column 266 is plugged in the third limiting hole 38, and is used for limiting the second limiting column 36, thereby fixing the two adjacent fixing columns 21, and the end of the second pressure relief hole 23 of the connecting component 3 is blocked by the plug 39. After the plug 39 is removed, the liquid in the second pressure relief hole 23 can be poured out. After the connecting component 3 and the supporting component 2 or the two groups of connecting components 3 are plugged in with each other, the front and rear groups of the second boost holes 22 are connected with each other.

[0026] When the second pressure boosting hole 22 is pressurized and liquid flows into it, the fourth blocking block 32 is subjected to the pressure drop and abuts against the bottom of the third connecting hole 31, thereby blocking the leakage hole 34 to prevent the liquid from entering the second pressure relief hole 23 when pressurized. When the pressure is relieved, the liquid pressure in the second pressure boosting hole 22 disappears, and the fourth blocking block 32 moves upward under the action of the third elastic member 33 and the liquid pressure in the second pressure relief hole 23, and the liquid in the second pressure relief hole 23 flows back into the second pressure boosting hole 22 from the leakage hole 34 and the third connecting hole 31.

[0027] Reference Figures 7 to 9 The expandable core shaft also includes a plurality of first core expansion blocks 4 distributed in a circular array around the axis of the fixed column 21. The outer surface of the first core expansion block 4 is an arc-shaped surface and the arc-shaped surface fits the inner diameter surface of the stator. The arc length of the first core expansion block 4 is greater than the stator slot width of the stator to avoid instability when the first core expansion block 4 expands to the inner diameter surface of the stator. The first core expansion block 4 is fixedly installed with a plurality of guide rods 5 perpendicular to the axis of the fixed column 21. The first core expansion block 4 is slidably connected to the fixed column 21 through the plurality of guide rods 5. The first core expansion block 4 is fixedly installed with a fourth elastic member 6 mounted on the guide rod 5. One end of the fourth elastic member 6 is fixedly connected to the guide rod 5, and the other end is fixedly connected to the fixed column 21. The fourth elastic member 6 is used to push the guide rod 5 so that the first core expansion block 4 abuts against the fixed column 21. The first core expansion block 4 is fixedly installed with a piston 7 that slidably cooperates with the pressurizing chamber 24. The pressurized liquid pushes the piston 7, thereby realizing the outward pushing of the first core expansion block 4. The installation structure of the first core expansion block 4 installed on the connecting assembly 3 is the same as the installation structure on the supporting assembly 2, and will not be repeated here.

[0028] The first core expanding block 4 is provided with a plurality of plug-in grooves 8 which are parallel to the axis of the fixed column 21, and the core expanding shaft also includes a second core expanding block 9. The outer surface of the second core expanding block 9 is an arc-shaped surface and fits with the corresponding inner diameter surface of the stator. A plug-in block 10 which is plugged into and matched with the plug-in grooves 8 is fixedly installed on the second core expanding block 9, so that the second core expanding block 9 can be plugged into the first core expanding block 4. A threaded hole 14 is provided on the first core expanding block 4, and a bolt passes through the second core expanding block 9 and is threadedly matched with the threaded hole 14, so that the second core expanding block 9 is locked on the first core expanding block 4. Through the arrangement of the first core expanding block 4, when the piston 7 is subjected to hydraulic thrust, the outer surfaces of several first core expanding blocks 4 are in contact with the inner diameter surface of the stator. When the hydraulic thrust is continuously provided, the several first core expanding blocks 4 tighten the inner diameter surface of the stator to achieve stator fixation, and effectively ensure the concentricity of the inner and outer circles during stator processing. In addition, the present invention can make the second core expanding block 9 replaceable by plugging the second core expanding block 9 on the first core expanding block 4. When fixing stators with different inner diameters, the second core expanding block 9 with different arc surfaces can be switched to perform expansion, thereby improving the flexibility of stator fixation.

[0029] Working principle: fix the positioning seat 1 by bolts, connect the connecting nozzle 13 to the boosting equipment, when the length of the stator is small and only one supporting component 2 is needed to expand, the stator is mounted on the fixing column 21 and abuts against the positioning seat 1, which is convenient for stator positioning, and the tail ends of the second boost hole 22 and the second pressure relief hole 23 are blocked by the blocking component 26, and the boosting liquid enters the second boost hole 22 and the boosting chamber 24 from the first boost hole 11. The boosting liquid pushes a number of pistons 7 and the first core expansion block 4 to move and compress the fourth elastic member 6. The outer surface of the first core expansion block 4 is in contact with the inner diameter surface of the stator and tightens the stator to achieve the fixation of the stator; after the pressure is released, the fourth elastic member 6 rebounds and drives a number of first core expansion blocks 4 to close to the axis of the fixing column 21, thereby releasing the fixation of the stator. At this time, the stator or the assembled stator can be removed. It should be noted that the pressurized liquid in the second boost hole 22 will also push the top block 28 and the third blocking block 210 to move. The top block 28 is pushed upward and its end abuts against the upper part of the first limiting hole 214. At this time, the bottom of the top block 28 has not separated from the first connecting hole 27 and can still maintain the blocked state.

[0030] When the length of the stator is much longer than the length of the supporting assembly 2, one or more connecting assemblies 3 need to be added, and the screw 264 at the mutually inserted joint is rotated to drive the first blocking block 261, the guide column 262 and the second blocking block 263 to move upward. At this time, the corresponding second boost hole 22 is connected to the first guide hole 251, the second pressure relief hole 23 is connected to the second connecting hole 212, the through hole 265 is connected to the first limiting hole 214, and the bottom of the first limiting column 266 is higher than the first limiting hole 214; the second limiting column 36 of the connecting assembly 3 is inserted into the previous pair The first limiting hole 214 is inserted into the corresponding one and the inclined surface of the top block 28 is pushed until the top block 28 is pressed down over the second limiting column 36 and inserted into the second limiting hole 37. At this time, the fixed column 21 of the connecting component 3 abuts against the tail end of the previous fixed column 21, and the positioning column 35 is inserted into the positioning groove 213 and abuts against the bottom of the positioning groove 213. The screw 264 is screwed to drive the first blocking block 261, the guide column 262 and the second blocking block 263 to move downward, and the first limiting column 266 is inserted into the third limiting hole 38 to limit the fixed column 21 of the connecting component 3. It should be noted that a sealing ring for sealing is provided at the end of the positioning column 35. When the first limiting column 266 is inserted into the third limiting hole 38, the end of the positioning column 35 is in a sealed state. The blocking component 26 on the connecting component 3 farthest from the supporting component 2 does not need to be adjusted and is still in a state of blocking the second boost hole 22 and the second pressure relief hole 23.

[0031] When boosting, the second boosting hole 22 is introduced with boosting liquid. Since the elastic force of the second elastic member 211 is greater than that of the first elastic member 29 and the third elastic member 33, the fourth blocking block 32 descends to block the third connecting hole 31. The boosting liquid pushes the top block 28 upward, so that the inclined surface of the top block 28 pushes the inner wall of the second limiting hole 37 of the second limiting column 36, thereby further improving the limiting stability of the second limiting column 36. When the liquid pressure continues to increase, the third blocking block 210 continues to move and compress the second elastic member 211 until the third blocking block 210 is out of the blocking state, so that the second boosting hole 22 is connected with the first guide hole 251, and the boosting liquid enters the second boosting hole 22 in the next connecting component 3 from the first guide hole 251. As the boosting liquid continues to be pressurized, the boosting liquid pushes several pistons 7 and the first core expansion block 4 to move and compress the fourth elastic member 6. The outer surface of the first core expansion block 4 is in contact with the inner diameter surface of the stator and tightens the stator to achieve stator fixation.

[0032] When the pressure is released, the liquid pressure in the second boost hole 22 disappears, the fourth elastic member 6 rebounds and drives the first core expansion blocks 4 to close toward the axis of the fixed column 21, and the fourth blocking block 32 moves upward under the action of the third elastic member 33 and the liquid pressure in the second pressure relief hole 23. The liquid in the second boost hole 22 in the connecting component 3 flows back into the previous second boost hole 22 through the previous second connecting hole 212, the second pressure relief hole 23, the leakage hole 34, and the third connecting hole 31 until it flows into the second pressure relief hole 23 of the supporting component 2, and then flows back into the boosting device, thereby realizing the liquid pressure reduction process.

[0033] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An expandable mandrel for stator machining to ensure the concentricity of inner and outer circles, characterized in that: The invention comprises a positioning seat (1) and a plurality of connecting components (3); the positioning seat (1) is provided with a first pressure-increasing hole (11) and a first pressure-relieving hole (12) connected to a pressure-increasing device; the positioning seat (1) is provided with a supporting component (2); The support assembly (2) comprises a fixing column (21) mounted on the positioning seat (1), the fixing column (21) being provided with a second pressure-increasing hole (22) communicating with the first pressure-increasing hole (11) and a second pressure-relieving hole (23) communicating with the first pressure-relieving hole (12). The fixed column (21) is provided with a blocking channel (25) communicating with the second pressure-increasing hole (22) and the second pressure-relieving hole (23), and a blocking component (26) for blocking the second pressure-increasing hole (22) and the second pressure-relieving hole (23) is slidably mounted in the blocking channel (25). A plurality of connection components (3) are plugged end to end or plugged with a support component (2) and fixed on the connection component (3) via a plugging component (26), and two adjacent second boosting holes (22) are connected after the plugging; The fixed column (21) is provided with a plurality of boosting chambers (24) which are in communication with the second boosting holes (22); A plurality of first core expansion blocks (4) are slidably mounted on the support assembly (2) and the connection assembly (3); the first core expansion blocks (4) are pulled and limited on the support assembly (2) or the connection assembly (3) by pulling the fourth elastic member (6); and a piston (7) slidably matched with the boosting chamber (24) is mounted on the first core expansion block (4); When pressurizing, the pressurized liquid pushes a plurality of pistons (7) to drive the corresponding first core expansion blocks (4) to move, so that the first core expansion blocks (4) expand the inner diameter of the product.

2. The expandable mandrel for stator machining to ensure the concentricity of inner and outer circles according to claim 1, characterized in that: The blocking channel (25) comprises a first guide hole (251) connected to the second pressure-increasing hole (22); the first guide hole (251) is connected to the second guide hole (252) and the third guide hole (253) at both ends; the third guide hole (253) is connected to the second pressure-relieving hole (23). The blocking assembly (26) comprises a first blocking block (261) slidably engaged with the first guide hole (251), the first blocking block (261) being used to control the conduction of the second boost hole (22), one end of the first blocking block (261) being fixedly connected to a guide column (262), and the other end being fixedly connected to a second blocking block (263), the guide column (262) being slidably engaged with the second guide hole (252), the second blocking block (263) sliding in the third guide hole (253), being used to control the conduction of the second pressure relief hole (23), and the end of the guide column (262) being rotatably connected to a screw rod (264) threadably engaged with the fixed column (21).

3. The expandable mandrel for stator machining to ensure the concentricity of inner and outer circles according to claim 2, characterized in that: The height of the first blocking block (261) is smaller than the height of the first guide hole (251).

4. The expandable mandrel for stator machining to ensure the concentricity of inner and outer circles according to claim 2, characterized in that: The connection assembly (3) differs from the support assembly (2) only in that a third connection hole (31) is provided on the fixed column (21) of the connection assembly (3) and is connected to both the second pressure-increasing hole (22) and the second pressure-relief hole (23); a fourth blocking block (32) is slidably connected in the third connection hole (31); a spacing is provided between the fourth blocking block (32) and the bottom of the third connection hole (31); a third elastic member (33) for pulling the fourth blocking block (32) is installed in the third connection hole (31); a plurality of leakage holes (34) for connecting the third connection hole (31) and the second pressure-relief hole (23) are provided on the fourth blocking block (32); A third blocking block (210) is slidably fitted in the second pressurizing hole (22), and a second elastic member (211) for pushing up the third blocking block (210) is installed in the second pressurizing hole (22).

5. The expandable mandrel for stator machining to ensure the concentricity of inner and outer circles according to claim 1, characterized in that: The fixing column (21) is provided with a positioning groove (213) connected to the second pressure-increasing hole (22), and the positioning groove (213) and the second pressure-increasing hole (22) are coaxial, and the second pressure-relieving hole (23) is connected to the second pressure-increasing hole (22) through the second connecting hole (212), and the connection is between the positioning groove (213) and the first guide hole (251). A positioning column (35) is fixedly mounted on one end of the connection assembly (3), the positioning column (35) is plugged into and matched with a corresponding positioning groove (213), and the second boost hole (22) passes through the positioning column (35) and is in communication with the previous second boost hole (22).

6. The expandable mandrel for stator machining to ensure the concentricity of inner and outer circles according to claim 4, characterized in that: The fixing column (21) is provided with a plurality of first limiting holes (214), and the first limiting holes (214) are parallel to the axis of the fixing column (21). A plurality of second limiting columns (36) are fixedly mounted on one end of the connection assembly (3), and the second limiting columns (36) are plugged into and matched with corresponding first limiting holes (214). The guide column (262) is provided with a through hole (265), a first limiting column (266) is fixedly installed in the through hole (265), and a third limiting hole (38) is provided on the second limiting column (36), the first limiting column (266) is inserted into the third limiting hole (38) for limiting and fixing the second limiting column (36).

7. The expandable mandrel for stator machining to ensure the concentricity of inner and outer circles according to claim 6, characterized in that: The fixing column (21) is provided with a plurality of first connection holes (27) connected to the second pressure-increasing holes (22); a top block (28) is slidably fitted in the first connection hole (27); the end of the top block (28) is inclined; and a first elastic member (29) for pushing the top block (28) is installed in the first connection hole (27); The third blocking block (210) is located between the first connecting hole (27) and the first guide hole (251). The second limiting column (36) is provided with a second limiting hole (37), and the top block (28) is inserted into the second limiting hole (37) to push the second limiting column (36) to be fixed; The end of the second pressure relief hole (23) of the connection assembly (3) is blocked by a plug (39).

8. The expandable mandrel for stator machining to ensure the concentricity of inner and outer circles according to claim 7, characterized in that: The elastic strength of the second elastic member (211) is greater than the elastic strength of the first elastic member (29).

9. The expandable mandrel for stator machining to ensure the concentricity of inner and outer circles according to any one of claims 1 to 8, characterized in that: A plurality of the first core expansion blocks (4) are distributed in a circular array around the axis of the fixed column (21); the outer surface of the first core expansion block (4) is an arc-shaped surface and the arc-shaped surface fits the inner diameter surface of the stator; the arc length of the first core expansion block (4) is greater than the stator slot width of the stator.

10. The expandable mandrel for stator machining to ensure the concentricity of inner and outer circles according to claim 9, characterized in that: The first core expansion block (4) is plugged with a second core expansion block (9) and fixed by a fastener; the outer surface of the second core expansion block (9) is an arc-shaped surface and fits with the corresponding inner diameter surface of the stator.

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