Self-centering device for gearbox housing machining

Abstract

This invention discloses a self-centering device for machining a gearbox housing, comprising: a fixture base plate, a positioning assembly disposed on the fixture base plate, and a centering body connected to the positioning assembly; the positioning assembly includes a positioning base, an oil-free bushing disposed inside the positioning base, a limiting cover disposed on the positioning base, and a spring assembly disposed within the positioning base; the centering body includes a positioning shaft disposed within the positioning base, a height limiting ring disposed on the positioning shaft, and a circumferential self-centering assembly, the spring assembly supporting the positioning shaft; the circumferential self-centering assembly is provided with at least one set of circumferentially expandable circumferential positioning pin assemblies and a pull rod assembly for driving the circumferential positioning pin assemblies to expand outward. This invention features an ingenious structural design, enabling the centering body to simultaneously center both upper and lower sets of self-centering components, and allowing the self-centering assembly to float vertically while simultaneously satisfying minute circumferential rotation, thereby improving positioning accuracy and operational convenience.

Description

Technical Field

[0001] This invention belongs to the field of centering technology for gearbox housing processing, and specifically relates to a self-centering device for gearbox housing processing. Background Technology

[0002] The transmission is one of the most important components of a car, significantly impacting its overall performance. The transmission housing is the structural enclosure used to house the transmission drive mechanism and related accessories. The transmission housing undergoes multiple processing steps, including cutting and grinding, during manufacturing. To ensure machining accuracy, the transmission housing needs to be precisely positioned before processing.

[0003] A centering device is used to position the gearbox housing. Currently, most methods for positioning automotive gearbox housings involve using a pressure plate to fix the housing and using a pre-cast hole on the bottom surface of the housing as a reference for positioning. However, this method is difficult to achieve precise positioning and is inconvenient to clamp, affecting product quality and production efficiency. Therefore, professionals in related fields have proposed other positioning devices, such as those described in "CN201920219164.1 A fixture for machining gearbox housings". Although these devices improve positioning accuracy and clamping convenience compared to the pressure plate and pre-cast hole method, they still struggle to achieve small vertical and circumferential floating positioning.

[0004] In view of the shortcomings of the prior art, this application provides a self-centering device.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a self-centering device for machining gearbox housings, thereby overcoming the defects in the prior art.

[0007] To achieve the above objectives, the present invention provides a self-centering device for machining a gearbox housing, comprising a fixture base plate, a positioning component disposed on the fixture base plate, and a centering body connected to the positioning component; The positioning component includes a positioning base, an oil-free bushing disposed inside the positioning base, a limiting cover disposed on the positioning base, and a spring assembly disposed inside the positioning base. The centering body includes a positioning shaft disposed in the positioning base, a height limiting ring disposed on the positioning shaft, and a circumferential self-centering component, wherein the spring component supports the positioning shaft; The circumferential self-centering assembly includes at least one set of circumferential positioning pin assemblies that can expand circumferentially and a pull rod assembly that drives the circumferential positioning pin assemblies to expand outward.

[0008] Furthermore, as a preferred embodiment, the spring assembly includes a spring sleeve, a support spring disposed within the spring sleeve, and a matching support head. The support head extends out of the spring sleeve, and the bottom of the positioning shaft is provided with a receiving cavity that is clearance-fitted with the spring sleeve. The support head abuts against the positioning shaft.

[0009] Furthermore, as a preferred embodiment, the bottom of the positioning shaft is provided with a support channel communicating with the receiving cavity, a support head is provided in the support channel, the support head abuts against the support head, and a screw is provided on the side of the positioning shaft to lock the head of the support head.

[0010] Furthermore, as a preferred embodiment, the side of the positioning shaft is also provided with a set screw, which locks the side of the support head.

[0011] Furthermore, as a preferred embodiment, the positioning base is provided with a fastening window, and the screws and set screws are screwed into the positioning shaft through the fastening window. The fastening window is provided with a protective cover plate.

[0012] Furthermore, as a preferred embodiment, the limiting cover is provided with a limiting hole, and the positioning shaft is provided with a cylindrical pin, the cylindrical pin being located inside the limiting hole, and the diameter of the cylindrical pin being smaller than the diameter of the limiting hole; the limiting cover is also provided with a dustproof ring.

[0013] Furthermore, as a preferred embodiment, the circumferential positioning pin assembly includes a circumferential centering seat, a centering shaft disposed within the circumferential centering seat, and an bulging structure tangent to the centering shaft. The centering shaft has a frustum structure, and the bulging structure is tangent to the outer peripheral surface of the frustum structure. The bulging structure is connected to the circumferential centering seat via an elastic component. The pull rod assembly includes a pull rod that passes through the centering shaft and extends outside the circumferential centering seat. Two washers are nested on the pull rod. One end of each washer is provided with a flat washer. A spring is provided between the two flat washers. The portion of the pull rod extending outside the circumferential centering seat is also provided with a compression washer and an adjusting nut.

[0014] Furthermore, as a preferred embodiment, the circumferential positioning pin assembly is provided in two sets.

[0015] Furthermore, as a preferred embodiment, the fixture base plate is provided with several clamping mechanisms, clamping mechanisms, and coarse positioning mechanisms.

[0016] Furthermore, as a preferred embodiment, the clamping mechanism includes a bottom support device and a pull-out elastic pressure plate device.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The centering body of the present invention can achieve micro-floating positioning in the vertical and circumferential directions, thereby improving the positioning accuracy; The invention features a clever structural design, employing a three-point positioning system that provides high positioning accuracy and ease of operation. The present invention provides a clamping mechanism, a holding mechanism and a coarse positioning mechanism on the base plate of the fixture, which can improve the clamping accuracy. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a self-centering device for machining a gearbox housing according to the present invention; Figure 2 This is a top view of a partial structure of a self-centering device for machining a gearbox housing according to the present invention; Figure 3 This is a partial structural cross-sectional view of a self-centering device for machining a gearbox housing according to the present invention. Figure 4 This is a cross-sectional enlarged schematic diagram of a portion of the structure of a self-centering device for machining a gearbox housing according to the present invention. Figure 5 This is an enlarged schematic diagram of the limiting cover of a self-centering device for machining a gearbox housing according to the present invention; Figure 6 This is an enlarged cross-sectional view of the limiting cover of a self-centering device for machining a gearbox housing according to the present invention; Figure 7 This is a partially enlarged schematic diagram of the circumferential positioning pin assembly of a self-centering device for machining a gearbox housing according to the present invention. Figure 8 This is a cross-sectional enlarged schematic diagram of the circumferential positioning pin assembly of a self-centering device for machining a gearbox housing according to the present invention; Figure 9 This is an enlarged cross-sectional view of the tie rod of a self-centering device for machining a gearbox housing according to the present invention; Figure 10 This is a cross-sectional enlarged schematic diagram of the bulging structure of a self-centering device for machining a gearbox housing according to the present invention; Figure 11 This is a partially enlarged schematic diagram of the fixture base plate of a self-centering device for machining a gearbox housing according to the present invention; Figure 12 , 13 This is a schematic diagram of the working state of a self-centering device for machining a gearbox housing according to the present invention; Figure Descriptions: 1-Clamp base plate, 11-Tightening mechanism, 111-Tightening base, 112-Support block, 113-Side positioning pin, 12-Clamping mechanism, 121-Bottom support device, 1211-Bottom support, 1212-Bottom support pin, 1213-Locking bolt, 122-Pull-out elastic pressure plate device, 1221-Pressure plate base, 1222-Elastic column, 1223-Pull-out pressure plate, 13-Coarse positioning mechanism, 2-Positioning assembly, 21-Positioning base, 211-Fixing plate, 212-Fastening window, 213-Protective cover, 22-Oil-free bushing, 23-Limit cover, 232-Dustproof ring, 231-Limit hole, 24-Spring assembly, 241-Spring sleeve, 242-Support spring, 243-Support head, 244-Support head, 245-Screw, 2 46-Setting screw, 3-Centering body, 31-Positioning shaft, 311-Receiving cavity, 312-Support channel, 313-Cylindrical pin, 32-Height limiting ring, 33-Circumferential self-centering assembly, 331-Circumferential positioning pin assembly, 3311-Circumferential centering seat, 3312-Centering shaft, 3313-Expanding structure, 33131-Expanding structure body, 33132-Ejector pin structure, 33133-Adjusting washer, 3314-Frustum structure, 332-Pull rod assembly, 3321-Pull rod, 3322-Washer, 3323-Flat washer, 3324-Spring, 3325-Compression washer, 3326-Adjusting nut, 333-Elastic assembly, 3331-Buffer spring, 3332-Locking screw, 334-Expanding space, 335-Cavity structure, 4-External positioning structure. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0020] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow. Example

[0021] This invention provides a self-centering device for machining a gearbox housing, comprising: a fixture base plate 1, a positioning component 2 disposed on the fixture base plate 1, and a centering body 3 connected to the positioning component 2; The positioning component 2 includes a positioning base 21, an oil-free bushing 22 disposed inside the positioning base 21, a limiting cover 23 disposed on the positioning base 21, and a spring assembly 24 disposed inside the positioning base 21. The centering body 3 includes a positioning shaft 31 disposed in the positioning base 21, a height limiting ring 32 disposed on the positioning shaft 31, and a circumferential self-centering component 33, and the spring component 24 supports the positioning shaft 31. The circumferential self-centering component 33 is provided with at least one set of circumferential positioning pin components 331 that can expand circumferentially and pull rod components 332 that drive the circumferential positioning pin components 331 to expand outward; the pull rod components 332 are connected to the positioning shaft 31.

[0022] In this embodiment, as a specific solution, the spring assembly 24 includes a spring sleeve 241, a support spring 242 disposed inside the spring sleeve 241, and a matching support head 243. The support head 243 extends out of the spring sleeve 241, and the bottom of the positioning shaft 31 is provided with a receiving cavity 311 that is clearance-fitted with the spring sleeve 241. The support head 243 abuts against the positioning shaft 31.

[0023] In this embodiment, as a specific solution, the bottom of the positioning shaft 31 is also provided with a support channel 312 communicating with the receiving cavity 311. A support head 244 is provided in the support channel 312, and the support head 243 abuts against the support head 244. A screw 245 is provided on the side of the positioning shaft 31, and the screw 245 locks the head of the support head 244.

[0024] In this embodiment, as a specific solution, the side of the positioning shaft 31 is also provided with a set screw 246, which locks the side of the support head 244.

[0025] In this embodiment, as a more specific solution, a fixing plate 211 is provided at the bottom of the positioning base 21. The fixing plate 211 is fixed to the positioning base 21 and the spring sleeve 241 by screws, bolts, etc. The support head 243 has a cross-shaped structure. The support spring 242 is sleeved on the lower section of the support head 243. As the support spring 242 extends and retracts, it can push the support head 243 to move up and down. The support head 244 has a bullet-shaped structure. The top of the support head 243 abuts against the tail of the support head 244. The screws 245 and the support head 244 are vertically distributed. The screws 245 are screwed into the side of the positioning shaft 31 and locked from the head of the support head 244.

[0026] In this embodiment, as a more specific solution, a fastening window 212 is provided on the positioning base 21, and the screw 245 and the set screw 246 are screwed into the positioning shaft 31 from the fastening window 212. A protective cover plate 213 is provided at the fastening window 212.

[0027] In this embodiment, the supporting force of the support spring 242 can be adjusted by combining the support head 244 and the screw 245. This force supports the weight of the circumferential self-centering assembly 33 and the workpiece, thus ensuring that the centering assembly can float up and down more easily. More specifically, when the support head 244 presses the entire support spring 242 tightly, the support spring 242 is in a contracted state and can provide greater supporting force. When the support head 244 is slightly raised, so that the support spring 242 is not contracted as tightly, that is, the support spring 242 is in a relaxed state, the supporting force it can provide is smaller. In this way, the weight of the workpiece can be estimated in advance and the supporting force of the entire support spring 242 can be adjusted appropriately to ensure that the centering assembly can float up and down more easily.

[0028] In this embodiment, as a specific solution, the frictional force of the positioning shaft 31 during its up-and-down floating and rotation can be reduced by placing the oil-free bushing 22 at the front and rear ends inside the positioning base 21.

[0029] In this embodiment, as a specific solution, the limiting cover 23 is provided with a limiting hole 231, and the positioning shaft 31 is provided with a cylindrical pin 313. The cylindrical pin 313 is located inside the limiting hole 231, and the diameter of the cylindrical pin 313 is smaller than the diameter of the limiting hole 231. The gap between the cylindrical pin 313 and the limiting hole 231 is the range of the centering body 3 to float up and down and rotate.

[0030] In this embodiment, as a specific solution, a dustproof ring 232 is also provided at the contact position between the limiting cover 23 and the positioning shaft 31, which can improve the dustproof performance.

[0031] In this embodiment, as a specific solution, the circumferential positioning pin assembly 331 includes a circumferential centering seat 3311, a centering shaft 3312 disposed in the circumferential centering seat 3311, and an bulging structure 3313 tangent to the centering shaft 3312. The centering shaft 3312 is provided with a frustum structure 3314, and the bulging structure 3313 is tangent to the outer peripheral surface of the frustum structure 3314. The bulging structure 3313 and the circumferential centering seat 3311 are connected by an elastic component 333. The pull rod assembly 332 includes a pull rod 3321 that passes through the centering shaft 3312 and extends to the outside of the circumferential centering seat 3311. Two washers 3322 are nested on the pull rod 3321. One end of each washer 3322 is provided with a flat washer 3323. A spring 3324 is provided between the two flat washers 3323. The part of the pull rod 3321 that extends to the outside of the circumferential centering seat 3311 is also provided with a compression washer 3325 and an adjusting nut 3326.

[0032] In this embodiment, as a more specific solution, the circumferential positioning pin assembly 331 is provided in two sets, and the two sets of circumferential positioning pin assemblies 331 share a pull rod 3321. One end of each of the two washers 3322 abuts against the top of the frustum structure 3314 of the two centering shafts 3312. When the adjusting nut 3326 is tightened, the adjusting nut 3326 causes the compression washer 3325 to press the centering shaft 3312 into the circumferential centering seat 3311. At this time, When the spring 3324 contracts, the frustum structure 3314 of the centering shaft 3312 presses against the expansion structure 3313, causing the expansion structure 3313 to expand outwards towards the outer periphery of the circumferential centering seat 3311. When the adjusting nut 3326 is loosened, the spring 3324 returns to its original position, and the frustum structure 3314 of the centering shaft 3312 and the expansion structure 3313 loosen. Under the action of the elastic component 333, the expansion structure 3313 contracts back towards the center of the circumferential centering seat 3311.

[0033] In this embodiment, as a more specific solution, the bulging structure 3313 consists of an bulging structure body 33131 and a pin structure 33132 disposed on the bulging structure body 33131. The pin structure 33132 is also provided with an adjusting washer 33133. The elastic component 333 consists of a buffer spring 3331 and a locking screw 3332. The locking screw 3332 is screwed onto the circumferential centering seat 3311. The buffer spring 3331 is disposed on the bulging structure body 33131. The locking screw 3332 presses against the buffer spring 3331. There is an bulging space 334 between the circumferential centering seat 3311 and the bulging structure body 33131 to accommodate the outward expansion of the bulging structure body 33131.

[0034] In this embodiment, as a more specific solution, each group of circumferential positioning pin assemblies 331 has three protruding structures 3313, or other numbers, but three are used as an example here. The three protruding structures 3313 are evenly tangent to the frustum structure 3314 of the centering shaft 3312, so that each circumferential positioning pin assembly 331 can position the workpiece to be processed from three points.

[0035] In this embodiment, as a more specific solution, the circumferential centering seat 3311 has a cavity structure 335 between the two sets of circumferential positioning pin assemblies 331, which enables the pull rod assembly 332 to work smoothly.

[0036] In this embodiment, as a specific solution, the fixture base plate 1 is provided with several clamping mechanisms 11, clamping mechanisms 12, and coarse positioning mechanisms 13.

[0037] In this embodiment, as a more specific solution, the clamping mechanism 11 consists of a clamping base 111 and a support block 112 disposed on the clamping base 111. The support block 112 is provided with an adjustable side positioning pin 113, which can be positioned from the outside of the workpiece. The clamping mechanism 12 includes a bottom support device 121 and a pull-out elastic pressure plate device 122. The bottom support device 121 consists of a bottom support 1211, a bottom support pin 1212 that can be finely adjusted up and down on the bottom support 1211, and a locking bolt 1213 that is provided on the bottom support 1211 for locking the bottom support pin 1212. The pull-out elastic pressure plate device 122 consists of a pressure plate base 1221, an elastic column 1222 disposed on the pressure plate base 1221, and a pull-out pressure plate 1223 connected to the elastic column. The bottom support pin 1212 and the pull-out pressure plate 1223 work together to press the workpiece down from the bottom and top, respectively.

[0038] The coarse positioning mechanism 13 is used to initially define the relative position of the centering body 2 and the workpiece to be processed.

[0039] In this embodiment, as a more preferred solution, an external positioning structure 4 is provided on the outside. When the above-mentioned centering operation is completed, the external positioning structure 4 completes the fine-tuning positioning in circumference and height. The external positioning structure 4 is directly connected to the machine tool. After the external positioning structure 4 completes the fine-tuning positioning, the workpiece will be clamped by several clamping mechanisms 11, clamping mechanisms 12 and coarse positioning mechanisms 13 on the fixture base plate 1, and then the next processing can be carried out.

[0040] The working principle of this invention is as follows: The workpiece to be processed (gearbox housing) is fitted onto the centering body 3. The coarse positioning mechanism 13 initially defines the relative position between the centering body 2 and the workpiece to be processed. The workpiece is supported by the height limiting ring 32. During the centering operation, when the adjusting nut 3326- is tightened, the adjusting nut 3326- causes the compression washer 3325 to press the centering shaft 3312 into the circumferential centering seat 3311. At this time, the spring 3324 contracts, and the frustum structure 3314 of the centering shaft 3312 presses against the expansion structure 3313, causing the expansion structure 3313 to expand outward from the circumferential centering seat 3311. The ejector pin structure 33132 of the expansion structure 3313 presses against the inner wall of the workpiece to achieve centering. During this process, the support spring 242 balances the weight of the workpiece and the circumferential self-centering assembly 33, thereby ensuring that the circumferential self-centering assembly 33 can float up and down more easily, so that the ejector pin structure 33132 can be fully aligned with the corresponding part inside the workpiece. Then, the workpiece is locked by the clamping mechanism 11 and the holding mechanism 12, and the next processing can be carried out.

[0041] The centering body 2 of the present invention can achieve micro-floating positioning in the vertical and circumferential directions, which can improve the positioning accuracy. The structure is ingeniously designed and adopts three-point positioning, which has high positioning accuracy and is convenient to operate. In addition, a clamping mechanism and a holding mechanism are provided on the fixture base plate. The holding mechanism can be appropriately adjusted by the elastic column, which can improve the holding accuracy.

[0042] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A self-centering device for machining a gearbox housing, characterized in that, include: The fixture base plate, the positioning component set on the fixture base plate, and the centering body connected to the positioning component; The positioning component includes a positioning base, an oil-free bushing disposed inside the positioning base, a limiting cover disposed on the positioning base, and a spring assembly disposed inside the positioning base. The centering body includes a positioning shaft disposed in the positioning base, a height limiting ring disposed on the positioning shaft, and a circumferential self-centering component, wherein the spring component supports the positioning shaft; The circumferential self-centering assembly is provided with at least one set of circumferential positioning pin assemblies that can expand circumferentially and a pull rod assembly that drives the circumferential positioning pin assemblies to expand outward. The circumferential positioning pin assembly includes a circumferential centering seat, a centering shaft disposed within the circumferential centering seat, and an extended structure tangent to the centering shaft. The centering shaft has a frustum structure, and the extended structure is tangent to the outer circumferential surface of the frustum structure. The extended structure is connected to the circumferential centering seat via an elastic component. The pull rod assembly includes a pull rod that passes through the centering shaft and extends to the outside of the circumferential centering seat. Two washers are nested on the pull rod. One end of each washer is provided with a flat washer. A spring is provided between the two flat washers. The part of the pull rod extending to the outside of the circumferential centering seat is also provided with a compression washer and an adjusting nut. The circumferential positioning pin assembly has two sets.

2. The self-centering device for machining a gearbox housing according to claim 1, characterized in that, The spring assembly includes a spring sleeve, a support spring disposed within the spring sleeve, and a matching support head. The support head extends out of the spring sleeve, and the bottom of the positioning shaft is provided with a receiving cavity that is clearance-fitted with the spring sleeve. The support head presses against the positioning shaft.

3. The self-centering device for machining a gearbox housing according to claim 2, characterized in that, The bottom of the positioning shaft is also provided with a support channel communicating with the receiving cavity. A support head is provided in the support channel, and the support head abuts against the support head. A screw is provided on the side of the positioning shaft, and the screw locks the head of the support head.

4. The self-centering device for machining a gearbox housing according to claim 3, characterized in that, The side of the positioning shaft is also provided with a set screw, which locks the side of the support head.

5. The self-centering device for machining a gearbox housing according to claim 4, characterized in that, The positioning base has a fastening window, and the screws and set screws are screwed into the positioning shaft through the fastening window. The fastening window is provided with a protective cover.

6. The self-centering device for machining a gearbox housing according to claim 1, characterized in that, The limiting cover is provided with a limiting hole, and the positioning shaft is provided with a cylindrical pin. The cylindrical pin is located inside the limiting hole, and the diameter of the cylindrical pin is smaller than the diameter of the limiting hole. The limiting cover is also provided with a dustproof ring.

7. The self-centering device for machining a gearbox housing according to claim 1, characterized in that, The fixture base plate is provided with several clamping mechanisms, holding mechanisms and coarse positioning mechanisms.

8. The self-centering device for machining a gearbox housing according to claim 7, characterized in that, The clamping mechanism includes a bottom support device and a pull-out elastic pressure plate device.

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