Motor rear end cover grinding positioning clamp

Abstract

The utility model relates to the field of clamping tool, disclose motor rear end cover grinding positioning fixture, including main part and be used for installing the main shaft of main part, and the main part includes connecting portion and clamping portion, and the connecting portion outer periphery is provided with the taper mounting surface for with the inner periphery positioning cooperation of main shaft, and the connecting portion's axle center is provided with the pull -out pin installation hole for installing pull -out pin, and the main shaft is provided with the pull -in claw subassembly for pulling the pull -out pin, the connecting portion and clamping portion integrally form an independent fixture unit, and motor rear end cover grinding positioning fixture is equipped with at least two fixture units, including first fixture unit and second fixture unit, the clamping portion of first fixture unit is set up as the first positioning piece for processing the outer circle and the hole of motor rear end cover, the clamping portion of second fixture unit is set up as the second positioning piece for positioning the inner end face of motor rear end cover and installing. The utility model intends to solve the problem of datum conversion error and poor repeatability caused by multiple sets of fixtures in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of clamping tooling technology, specifically to a grinding and positioning fixture for the rear end cover of a motor. Background Technology

[0002] In the manufacturing process of small motors, the rear end cover is a critical component. The machining accuracy of its outer diameter, inner bore, and inner end face directly affects the overall performance, assembly quality, and service life of the motor. The outer diameter needs to achieve a precise fit with the motor housing to ensure sealing and structural stability; the inner bore usually fits with the bearing housing, requiring extremely high dimensional accuracy and roundness to reduce vibration and wear during operation; the inner end face is responsible for axial positioning, affecting the axial clearance and smooth operation of the motor rotor. Grinding is a key process to ensure that these features meet design requirements. It effectively removes excess material left from previous processes, improves surface roughness, and ensures that geometric tolerances meet standards. Insufficient grinding accuracy in these areas may lead to decreased motor efficiency, increased noise, or premature failure. Therefore, a high-precision grinding process is crucial for the reliability and consistency of small motors.

[0003] Currently, the industry mainly uses a combination of multiple specialized machine tools and specialized fixtures for grinding motor rear end covers. This means that separate positioning fixtures are designed for the outer diameter, inner hole, and inner end face, and are configured on different machine tools. For example, a fixture with positioning based on the inner hole and end face is used when grinding the outer diameter, a fixture with positioning based on the outer diameter and end face is used when grinding the inner hole, and a different type of fixture is required when grinding the inner end face.

[0004] The inherent drawbacks of this model are as follows: First, small motor rear end covers are generally produced in small batches, so setting up multiple machine tools and fixtures requires designing, manufacturing, and managing multiple sets of fixtures, resulting in high costs. Second, when workpieces are transferred between multiple fixtures, reference conversion errors are inevitable, making it difficult to guarantee the high coaxiality and perpendicularity requirements between the machined surfaces, thus restricting further improvement in product accuracy. Third, the production line occupies a large area, has cumbersome process turnover, and low production efficiency. Utility Model Content

[0005] The present invention aims to provide a grinding and positioning fixture for the rear end cover of a motor, so as to solve the problems of reference conversion error and poor repeatability positioning accuracy caused by multiple sets of fixtures in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A grinding and positioning fixture for a motor rear end cover includes a main body and a spindle for mounting the main body. The main body includes a connecting part and a clamping part. The outer periphery of the connecting part is provided with a tapered mounting surface for positioning and engaging with the inner periphery of the spindle. The shaft center of the connecting part is provided with a pull stud mounting hole for mounting a pull stud. The spindle is provided with a pull claw assembly for tightening the pull stud. The connecting part and the clamping part are integrally formed to form an independent fixture unit. The grinding and positioning fixture for a motor rear end cover includes at least two fixture units, including a first fixture unit and a second fixture unit. The clamping part of the first fixture unit is configured as a first positioning element for machining the outer circle and inner hole of the motor rear end cover. The clamping part of the second fixture unit is configured as a second positioning element for positioning and mounting the inner end face of the motor rear end cover.

[0007] Beneficial effects: 1. By configuring at least two independent fixture units with identical connecting structures but specialized clamping functions, the first fixture unit is used for the outer circle and inner hole, and the second fixture unit is used for the inner end face, achieving efficient and continuous composite machining. This allows the operator to switch machining processes without disassembling and readjusting the hydraulic chuck and spindle on the machine tool. Instead, the operator simply pulls the entire fixture unit out of the spindle and replaces it, just like changing a standard tool holder. This greatly reduces the auxiliary time between processes and completely eliminates the positioning errors that may be caused by re-clamping the spindle.

[0008] 2. The integrated molding structure of the connecting part and the clamping part fundamentally avoids the gaps and cumulative errors that exist at the connection point in the split design, ensuring overall rigidity. The tapered mounting surface on the outer periphery of the connecting part and the tapered centering formed by the positioning cooperation with the inner periphery of the spindle provide extremely high radial positioning accuracy and a large support area. At the same time, the pull stud mounting hole set in the shaft and the pull claw assembly in the spindle provide a strong axial locking force by pulling from the axial direction. This combination forms a classic positioning method similar to the machine tool spindle tool holder, which makes the workpiece, fixture and spindle have the outstanding advantages of high repeatability and good connection rigidity, and can effectively resist grinding force, thereby ensuring the final machining accuracy.

[0009] Preferably, as an improvement, the first positioning member includes a connecting ear and a positioning part. The connecting ear extends in the radial direction of the main body and is fixedly connected to the rear end cover of the motor. The end of the main body away from the connecting part extends in the axial direction to form the positioning part, which is engaged with the inner hole of the rear end cover of the motor.

[0010] Beneficial effects: The axially extended positioning part engages with the inner hole of the workpiece, firstly completing the precise radial initial positioning and automatic alignment of the workpiece, establishing a precise reference for the subsequent grinding of the inner hole and outer circle, thus ensuring the uniformity of wall thickness and concentricity after machining; while the radially extended connecting lugs, in conjunction with the bolts, achieve reliable axial clamping of the workpiece, and the huge clamping force generated firmly presses the workpiece onto the positioning surface of the fixture, effectively preventing the axial movement or vibration that may occur in the workpiece during grinding, fundamentally ensuring the stability and safety of the machining process of the outer circle and inner hole.

[0011] Preferably, as an improvement, the second positioning member includes a clamping head connected to the end of the main body away from the connecting part, and the clamping head has a U-shaped cross-section. The motor rear end cover is located in the groove of the clamping head, and the end face of the motor rear end cover is fixedly connected to the end face of the clamping head.

[0012] Beneficial effects: The U-shaped groove structure forms a natural positioning cavity, which effectively wraps around the outer contour of the workpiece and provides radial restraint, enhancing the overall stability of the clamping; moreover, the structure completely exposes the inner end face of the workpiece to be processed, providing unobstructed processing space.

[0013] Preferably, as an improvement, weight-reducing holes are provided at the axis of both the first positioning member and the second positioning member.

[0014] Beneficial effects: The weight reduction hole effectively reduces the overall mass and moment of inertia of the high-speed rotating fixture unit, reduces the load on the drive motor, and creates the necessary conditions for dynamic balancing of the fixture. Through good dynamic balancing, the vibration caused by centrifugal force due to mass imbalance during high-speed machining can be significantly reduced or even eliminated. This is crucial for high-precision grinding with high surface quality, and can effectively avoid defects such as "vibration marks". Thus, while ensuring machining quality, it also protects the machine tool spindle bearings and extends the service life of the equipment.

[0015] Preferably, as an improvement, a locking block is provided at the end of the mounting surface away from the mounting groove, and the locking block is over-positioned connected to the end of the spindle.

[0016] Beneficial effects: The conical surface fit mainly solves radial positioning and part of axial positioning, while the added chuck makes close contact with the spindle end face, which greatly enhances the fixture's ability to resist axial cutting force and counter-torque, effectively preventing the fixture from slight axial movement or circumferential rotation that may occur within the spindle. This further improves the rigidity and stability of the entire fixture when subjected to heavy-duty grinding or intermittent cutting, ensuring the reliability of machining accuracy.

[0017] Preferably, as an improvement, the puller assembly includes a puller and a connecting post, the puller being rotatably mounted on the connecting post, and the connecting post being snapped into the spindle.

[0018] Beneficial effects: The hinged structure formed by the pin allows the pull claw to move like a flexible lever, adaptively engaging and disengaging with the snap-fit ​​connector. It generates a huge centripetal force when tightening and automatically swings out when releasing, ensuring precise and reliable operation. The connecting post is fixed inside the spindle by snap-fit, which is a simple and reliable fixing method. This not only facilitates the overall installation, debugging, and maintenance of the pull claw assembly, but more importantly, it ensures the correct working position of the pull claw assembly in the spindle, so that the line of action of the tensioning force is always consistent with the spindle axis, thereby ensuring the symmetry and stability of the clamping action. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of the installation of the positioning clamp in an embodiment of this utility model.

[0020] Figure 2 This is a schematic diagram of the structure of the first clamping unit in an embodiment of the present invention.

[0021] Figure 3 This is a cross-sectional view of the installation of the first clamping unit and the rear end cover of the motor in an embodiment of this utility model.

[0022] Figure 4 This is a schematic diagram of the structure of the second clamping unit in an embodiment of the present invention.

[0023] Figure 5 This is a cross-sectional view of the installation of the second clamping unit and the rear end cover of the motor in an embodiment of this utility model.

[0024] The reference numerals in the accompanying drawings include: spindle 1, connecting part 2, tapered mounting surface 21, mounting hole 22, locking block 23, pull stud 3, pull claw assembly 4, pull claw 41, connecting column 42, first positioning element 5, connecting ear 51, positioning part 52, second positioning element 6, clamping head 61, groove 62, and weight reduction hole 7. Detailed Implementation

[0025] The following detailed description illustrates the specific implementation method: The basic implementation examples are as follows: Figures 1-5 As shown: like Figure 1As shown, this embodiment provides a grinding positioning fixture for a motor rear end cover, including a main body and a spindle 1 for mounting the main body. During grinding, the spindle 1 is clamped by a hydraulic chuck, thereby clamping the workpiece. In this embodiment, the main body includes a connecting part 2 and a clamping part. The outer periphery of the connecting part 2 is provided with a tapered mounting surface 21 for positioning and cooperating with the inner periphery of the spindle 1, with a taper of 7:24. A locking block 23 is provided at the end of the mounting surface away from the mounting groove, and the locking block 23 is over-positioned connected to the end of the spindle 1. The connecting part 2 has a rivet 3 mounting hole 22 for mounting the rivet 3 on its shaft center. The main shaft 1 has a claw assembly 4 for tightening the rivet 3. The claw assembly 4 includes a claw 41 and a connecting post 42. The claw 41 is rotatably mounted on the connecting post 42 by a pin. The connecting post 42 is snapped into the main shaft 1. Specifically, the connecting post 42 has a groove 62 formed at one end inside the main body. The claw 41 has a first snap-fit ​​part and a second snap-fit ​​part at both ends. The first snap-fit ​​part is snapped into the groove 62. The second snap-fit ​​part extends towards the axis of the main body and snaps into the snap-fit ​​part at the end of the rivet 3.

[0026] The connecting part 2 and the clamping part are integrally formed to form an independent clamping unit. The motor rear end cover grinding and positioning fixture is equipped with at least two clamping units, including a first clamping unit and a second clamping unit; for example Figure 2 and Figure 3 As shown, the clamping part of the first fixture unit is configured as a first positioning member 5 for machining the outer circle and inner hole of the motor rear end cover; the first positioning member 5 includes a connecting ear 51 and a positioning part 52. The connecting ear 51 extends in the radial direction of the main body and is fixedly connected to the motor rear end cover by bolts. The end of the main body away from the connecting part 2 extends in the axial direction to form the positioning part 52, which is engaged in the inner hole of the motor rear end cover.

[0027] like Figure 4 and Figure 5 As shown, the clamping part of the second clamping unit is configured as a second positioning member 6 for positioning and installing the inner end face of the motor rear end cover. The second positioning member 6 includes a clamping head 61, which is connected to the end of the main body away from the connecting part 2. The cross-section of the clamping head 61 is U-shaped. The motor rear end cover is located in the groove 62 of the clamping head 61, and the end face of the motor rear end cover is fixedly connected to the end face of the clamping head 61 by bolts.

[0028] Weight reduction holes 7 are provided at the axis of both the first positioning member 5 and the second positioning member 6.

[0029] When using this motor rear end cover grinding and positioning fixture, the machining of the outer circle, inner hole, and inner end face of the motor rear end cover is completed step by step through two independent fixture units. The outer circumference of its spindle 1 is mounted on the machine tool through hydraulic jaws to transmit power. The complete usage process is as follows: First, the grinding of the outer circle and inner hole of the motor rear end cover is performed. This process requires the use of the first fixture unit. During operation, the pull stud 3 is first screwed into the pull stud 3 mounting hole 22 in the center of the connecting part 2. Then, the tapered mounting surface 21 on the connecting part 2 of the first fixture unit is positioned and engaged with the inner circumference of the spindle 1. The locking block 23 located at the higher point of the tapered mounting surface 21 is used to achieve over-positioning connection with the end of the spindle 1. Subsequently, the first fixture unit is installed in the spindle 1. The pull claw assembly 4 inside the spindle 1 is activated. The second locking part of the pull claw 41 clamps the locking joint of the pull stud 3, thereby pulling the entire fixture unit towards the spindle 1 to ensure stable positioning. Next, the motor rear end cover is installed on the clamping part of the first clamping unit, so that the positioning part 52, which extends axially from the main body, is inserted into the inner hole of the workpiece to achieve radial positioning. At the same time, the workpiece is fixed by bolts using the radially extended connecting lug 51. After clamping, the equipment can be started to grind the outer diameter and inner hole. Since the connecting part 2 of the first clamping unit and the second clamping unit has the same structure, after the outer diameter and inner hole are processed, it is only necessary to loosen the pull claw assembly 4 and remove the pull stud 3 along with the first clamping unit from the spindle 1. Without adjusting the hydraulic chuck on the machine tool, the second clamping unit with the pull stud 3 installed can be directly replaced and tightened in the same way to perform grinding of the inner end face of the rear end cover. When clamping the workpiece, the rear end cover of the motor is placed in the U-shaped groove 62 of the clamping head 61 of the second clamping unit, and the end face of the workpiece is fixedly connected with the end face of the clamping head 61 to achieve end face positioning. Then, the inner end face can be ground. The entire system transmits power by clamping the spindle 1 with a hydraulic chuck. Both clamping units are equipped with weight reduction holes 7 to optimize dynamic performance, thus completing the entire grinding task of the rear end cover of the motor efficiently and with high precision.

[0030] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A grinding and positioning fixture for the rear end cover of a motor, characterized in that: The fixture includes a main body and a spindle for mounting the main body. The main body includes a connecting part and a clamping part. The outer periphery of the connecting part is provided with a tapered mounting surface for positioning and engaging with the inner periphery of the spindle. The shaft center of the connecting part is provided with a pull stud mounting hole for mounting a pull stud. The spindle is provided with a pull claw assembly for tightening the pull stud. The connecting part and the clamping part are integrally formed to form an independent fixture unit. The motor rear end cover grinding and positioning fixture is configured with at least two fixture units, including a first fixture unit and a second fixture unit. The clamping part of the first fixture unit is configured as a first positioning element for machining the outer circle and inner hole of the motor rear end cover. The clamping part of the second fixture unit is configured as a second positioning element for positioning and mounting the inner end face of the motor rear end cover.

2. The motor rear end cover grinding and positioning fixture according to claim 1, characterized in that: The first positioning component includes a connecting ear and a positioning part. The connecting ear extends radially along the main body and is fixedly connected to the rear end cover of the motor. The end of the main body away from the connecting part extends axially to form the positioning part, which is engaged with the inner hole of the rear end cover of the motor.

3. The motor rear end cover grinding and positioning fixture according to claim 1, characterized in that: The second positioning component includes a clamping head connected to the end of the main body away from the connecting part, and the clamping head has a U-shaped cross-section. The rear end cover of the motor is located in the groove of the clamping head, and the end face of the rear end cover of the motor is fixedly connected to the end face of the clamping head.

4. The motor rear end cover grinding and positioning fixture according to claim 3, characterized in that: Weight reduction holes are provided at the axis of both the first and second positioning components.

5. The motor rear end cover grinding and positioning fixture according to claim 1, characterized in that: A locking block is provided at the end of the mounting surface away from the mounting slot, and the locking block is over-positioned to the end of the spindle.

6. The motor rear end cover grinding and positioning fixture according to claim 1, characterized in that: The puller assembly includes a puller and a connecting post. The puller is rotatably mounted on the connecting post, and the connecting post is snapped into the spindle.

Images