Adjustable grinding mandrel clamp and machining method thereof

Abstract

The invention relates to the technical field of shaft sleeve grinding machining, in particular to an adjustable grinding mandrel clamp and a machining method thereof. The adjustable grinding mandrel clamp comprises a mandrel, a sliding block and a locking screw, a protruding circular ring is arranged on a mandrel body, a plurality of slope grooves extending in the axial direction of the mandrel are formed in the protruding circular ring, grooves are formed in the slope grooves, one end of each groove penetrates through the protruding circular ring, a threaded hole is formed in the other end of each groove, and the sliding block is arranged in the threaded hole. The sliding block is arranged in the groove in a sliding mode, the locking screw is arranged on the sliding block in a penetrating mode and matched with the sliding block in a clamping mode, the locking screw extends into the groove to be in threaded connection with the threaded hole, and when the locking screw is screwed, the sliding block can move in the direction of the mandrel body and fix an inner hole of a workpiece. According to the adjustable grinding mandrel clamp, the outer circle of the large plunger sleeve of the low-speed machine can be machined, the problem that the large plunger sleeve cannot stably meet the coaxiality requirement after being machined on an outer circle grinding machine is solved, and meanwhile the machining process is simpler and faster.

Description

Technical Field

[0001] This invention relates to the field of bushing grinding technology, and in particular to an adjustable grinding mandrel fixture and its processing method. Background Technology

[0002] The large plunger sleeve of the low-speed engine is a relatively large bushing component and one of the core components in the fuel and gas injection system of marine low-speed engines. It requires high coaxiality between its inner and outer diameters. Due to the long inner diameter and large space of this type of part, the dimensional tolerances after machining are large and the form and position differences are significant. Using a designed tapered mandrel makes axial positioning difficult during grinding clamping. Each grinding cycle requires adjustment of the grinding wheel feed range, resulting in low grinding efficiency for the outer diameter. Furthermore, the form and position differences during hole machining mean that the coaxiality after grinding cannot be consistently guaranteed to meet standards. Designing stepped cylindrical mandrels of multiple specifications improves grinding efficiency, but if the clearance between the parts is slightly too large, the coaxiality of the inner and outer diameters after grinding is difficult to guarantee. Even with small clearances, the coaxiality of some parts will exceed the tolerance, and finding the corresponding cylindrical mandrel each time reduces efficiency. Additionally, if the machining dimensional tolerances are too large, a mandrel of the required specification may not be available, making it impossible to grind the outer diameter and delaying production.

[0003] To address the aforementioned issues, existing technologies employ cylindrical grinding machine fixtures for sleeve-type parts. These fixtures include a mandrel, a spring, wedges, a wedge guide sleeve, a pressure block, and a nut. The mandrel has center holes on both ends and a step at one end, with a spring mounted on the step. The wedge guide sleeve is fitted onto the mandrel, with its larger end pressed tightly against the end face of the step. Guide grooves are evenly distributed on the outer cylindrical surface of the wedge guide sleeve. A set of wedges, adapted to the wedge guide sleeve, are inserted into the guide grooves via lower guide bars and positioned on the wedge guide sleeve, with the smaller end of each wedge connected to the spring. The pressure block is fitted onto the mandrel and pressed against the larger end of the wedge by the nut.

[0004] The above-mentioned fixture uses wedge-block linkage clamping and has a compact structure, which can effectively reduce the labor intensity of workers and improve production efficiency. However, its adjustment accuracy is limited because it is difficult to directly select the wedge with the highest accuracy. Fixing workpieces with different hole diameters can be achieved by changing different wedges. It is quite troublesome to prepare multiple wedges of different diameters and fix them at the same time. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an adjustable grinding mandrel fixture, which can process the outer diameter of the large plunger sleeve of a low-speed machine and is convenient for adjustment and alignment, solving the problem that it cannot stably achieve the coaxiality requirement after processing on an external cylindrical grinding machine, and at the same time making the processing simpler and faster.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: In a first aspect, the present invention provides an adjustable grinding mandrel fixture, comprising a mandrel, a slider, and a locking screw. The mandrel body is provided with a raised ring, the raised ring having a plurality of inclined grooves extending along the mandrel axial direction, the inclined grooves having grooves, one end of the grooves passing through the raised ring, and the other end of the groove having a threaded hole. The slider is slidably disposed in the groove, the locking screw passing through the slider and forming a snap-fit ​​engagement with the slider, and the locking screw extending into the groove and threadedly connected to the threaded hole. When the locking screw is tightened, the slider can move along the direction of the mandrel body and fix the inner hole of the workpiece.

[0007] Furthermore, the mandrel body is symmetrically provided with raised annulus rings, and the slope height of the inclined groove increases towards the center of the mandrel body.

[0008] Furthermore, the locking screw includes a screw head, a screw rod, and a limiting ring. The screw head and one end of the screw rod are integrally formed, the other end of the screw rod is provided with external threads, and the limiting ring is fixedly sleeved on the body of the screw rod.

[0009] Furthermore, the slider has a semi-T-shaped structure, and the slider includes a connecting fitting guide and a driving limiting part. The fitting guide is located outside the groove, and the driving limiting part is located inside the groove. The outer surface of the fitting guide is arc-shaped.

[0010] Furthermore, the drive limiting part includes a mounting base and two limiting blocks symmetrically arranged at the bottom of the mounting base, and a drive channel extending along the direction of the spindle shaft is formed between the relative inner sidewalls of the two limiting blocks.

[0011] Furthermore, the diameter of the drive channel is smaller than the diameter of the screw head and the limiting ring, the diameter of the drive channel is larger than the diameter of the screw, and the radial dimension of the drive channel is larger than the diameter of the screw. The screw head and the limiting ring are located on both sides of the drive channel and engage with the limiting block.

[0012] Furthermore, the two limiting blocks are provided with mounting holes facing each other, and anti-detachment pins are provided at the mounting holes to prevent the screw from disengaging from the drive channel.

[0013] Furthermore, a positioning ring is provided in the middle of the shaft of the mandrel, and the diameter of the positioning ring is the same as the diameter of the raised ring.

[0014] Furthermore, a central hole is provided at both ends of the mandrel.

[0015] Secondly, the present invention also provides a method for machining an adjustable grinding mandrel fixture, which uses the adjustable grinding mandrel fixture described in the first aspect to machine a bushing, comprising the following steps: S1: Place the adjustable grinding mandrel fixture into the inner hole of the workpiece, and ensure that both ends of the mandrel extend beyond the inner hole of the workpiece by a preset distance. Then tighten the locking screw to initially fix the slider and the inner hole of the workpiece. S2: The entire fixture and workpiece are hoisted onto the grinding machine and fixed using the mandrel body. The inner hole of the workpiece is aligned using a dial indicator after initial fixing. By adjusting the locking screws, the center of the inner hole of the workpiece is made to coincide with the axis of the mandrel body, which facilitates the subsequent outer cylindrical grinding of the workpiece.

[0016] The beneficial effects of this invention are: 1. The adjustable grinding mandrel fixture of the present invention achieves adaptive fixing of the inner hole of the workpiece by moving the slider along the inclined groove. With the precise adjustment of the locking screw, it can effectively eliminate the influence of the form and position error of the inner hole of the workpiece on the machining, solve the problem that the coaxiality of the large plunger sleeve of the low speed machine is difficult to meet the standard after machining on the external cylindrical grinding machine, and ensure the coaxiality accuracy of the inner hole and the outer circle.

[0017] 2. Compared with traditional tapered mandrels or fixed-specification stepped mandrels, the adjustable grinding mandrel fixture of the present invention does not require the replacement of accessories of different sizes. It can be adapted to workpieces with different hole diameter tolerances by adjusting the position of the slider, reducing tooling preparation time. It is especially suitable for processing parts with large fluctuations in hole diameter after turning, avoiding the situation where grinding is impossible due to dimensional deviations.

[0018] 3. The adjustable grinding mandrel fixture processing method of the present invention allows for initial workpiece fixation by tightening the locking screws during processing. Positioning is then achieved by adjusting the locking screws using a dial indicator, eliminating the tedious steps of replacing wedges or mandrels. Furthermore, the center holes at both ends of the mandrel facilitate positioning with the grinding machine, making the overall operation faster, reducing worker workload, and improving grinding efficiency. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.

[0020] Figure 1 This is a schematic diagram of the adjustable grinding mandrel fixture of the present invention; Figure 2 This is a cross-sectional view of the adjustable grinding mandrel fixture of the present invention; Figure 3 This is a schematic diagram of the mandrel structure of the present invention; Figure 4 This is a schematic diagram of the locking screw and slider forming a snap-fit ​​engagement according to the present invention; Figure 5 This is a schematic diagram of the slider structure of the present invention; Figure 6 This is a schematic diagram of the locking screw of the present invention; Figure 7 This is a schematic diagram of the adjustable grinding mandrel clamp of the present invention clamping a certain low-speed machine plunger assembly.

[0021] Explanation of reference numerals in the attached drawings: 1-Mandrel, 11-Positioning ring, 12-Center hole, 2-Slider, 21-Fitting guide part, 22-Drive limiting part, 221-Mounting base, 222-Limiting block, 223-Anti-detachment pin, 3-Locking screw, 31-Screw head, 32-Screw rod, 33-Limiting ring, 4-Raised ring, 5-Beveled groove, 6-Groove. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] In the description of this invention, it should be understood that the terms "connected," "linked," and "fixed," etc., used in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or a welded connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Example 1: like Figures 1-7As shown, the present invention provides an adjustable grinding mandrel fixture, which includes a mandrel 1, a slider 2, and a locking screw 3. The mandrel 1 has a raised ring 4 on its shaft body. The raised ring 4 has several inclined grooves 5 extending along the axial direction of the mandrel 1. The inclined grooves 5 have grooves 6. One end of the groove 6 passes through the raised ring 4, and the other end of the groove 6 has a threaded hole. The slider 2 slides in the groove 6. The locking screw 3 passes through the slider 2 and forms a snap-fit ​​engagement with the slider 2. The locking screw 3 extends into the groove 6 and is threadedly connected to the threaded hole. When the locking screw 3 is tightened, the slider 2 can move along the axial direction of the mandrel 1 and fix the inner hole of the workpiece. In actual use, the inclined groove 5 and recessed groove 6 on the raised ring 4 provide a stable sliding track for the slider 2. The slider 2 slides within the recessed groove 6, and its position is locked by the threaded connection between the locking screw 3 and the threaded hole. When the locking screw 3 is tightened, the slider 2 moves axially along the spindle 1. Utilizing the guiding effect of the inclined groove 5, it can tightly fit against the inner hole of the workpiece, forming a firm fixation. This is especially suitable for large bushing-type parts such as large plunger sleeves in low-speed machines, solving the problem of unstable fixation in traditional fixtures. The snap-fit ​​engagement between the slider 2 and the locking screw 3, combined with the design of the recessed groove 6 and the threaded hole, allows the position of the slider 2 to be flexibly adjusted by the tightening degree of the locking screw 3. This adjustment capability can adapt to workpieces with different inner hole size tolerances without the need to change the fixture. To address the issue of significant differences in hole shape and position after turning, this solution avoids the compatibility problems caused by the limited specifications of traditional stepped mandrels 1. During assembly, simply insert the slider 2 into the groove 6, pass the locking screw 3 through the slider 2 and connect it to the threaded hole, and tighten it to complete the initial fixation. The operation is simple. Compared to traditional fixtures that require replacing wedges or mandrels 1, this eliminates the tedious disassembly, assembly, and specification matching steps, significantly shortening the clamping time and improving processing efficiency. When the slider 2 moves along the axis of the mandrel 1, its close contact with the inner hole of the workpiece helps to calibrate the workpiece position, effectively ensuring that the center of the inner hole of the workpiece coincides with the axis of the mandrel 1, providing a stable reference for external cylindrical grinding, and solving the technical problem of difficulty in achieving stable coaxiality after machining.

[0026] In a preferred embodiment of this invention, the mandrel 1 is symmetrically provided with raised rings 4, and the inclined surface height of the inclined groove 5 increases towards the center of the mandrel 1. In actual use, the symmetrically arranged raised rings 4 can provide symmetrical support to the inner hole of the workpiece from both ends of the mandrel 1, ensuring uniform force on the workpiece during clamping and preventing tilting or displacement of the workpiece due to unilateral force. This is particularly suitable for long, low-speed machine parts such as large plunger sleeves, ensuring stability during processing. The inclined surface height of the inclined groove 5 increases towards the center of the mandrel 1. When the slider 2 moves along the inclined groove 5 towards the center of the mandrel 1, the contact guide 21 gradually expands outward with the increase in inclined surface height, thus tightly contacting and pressing against the inner hole of the workpiece. This structural design allows the slider 2 to convert axial movement into radial clamping force. It can adapt to workpieces with different hole diameters and can be flexibly adjusted without changing the fixture accessories. The symmetrical raised rings 4 and the inclined grooves 5 cooperate to enable multiple sliders 2 to apply clamping force synchronously from symmetrical positions in the inner hole of the workpiece, ensuring the coaxiality of the inner hole of the workpiece and the axis of the mandrel 1, reducing the form and position errors caused by uneven force, and laying the foundation for high-precision coaxiality in subsequent external cylindrical grinding. The symmetrically distributed raised rings 4 strengthen the shaft of the mandrel 1 and improve the overall anti-deformation ability of the mandrel 1. Especially when bearing the weight of the workpiece and the grinding force, it can reduce the bending or vibration of the mandrel 1 and ensure the structural stability during the processing.

[0027] In a preferred embodiment of this invention, the locking screw 3 includes a screw head 31, a screw rod 32, and a limiting ring 33. The screw head 31 is integrally formed with one end of the screw rod 32, and the other end of the screw rod 32 is provided with an external thread. The limiting ring 33 is fixedly sleeved on the body of the screw rod 32. In actual use, the screw head 31 and the screw rod 32 are integrally formed, which can directly and efficiently transmit the external force during tightening to the screw rod 32, ensuring a stable fit between the screw rod 32 and the threaded hole in the groove 6, providing a continuous driving force for the movement of the slider 2. The limiting ring 33 is fixedly sleeved on the body of the screw rod 32, and is located on both sides of the drive channel of the slider 2, respectively, along with the screw head 31. Through the engagement with the limiting block 222, it forms a bidirectional limiting of the slider 2. When the locking screw 3 is tightened, this structure can accurately drive the slider 2 to move along the inclined groove 5, avoiding relative slippage between the slider 2 and the screw rod 32, ensuring adjustment accuracy. The fixed setting of the limiting ring 33 further enhances the stability of the fit between the screw rod 32 and the slider 2. The integrally formed screw head 31 and screw rod 32 are easy to process and assemble, without the need for additional connection processes. The fixed sleeve structure of the limiting ring 33 makes the fit between the locking screw 3 and the slider 2 more convenient. It is only necessary to insert the screw rod 32 into the drive channel to form a snap-fit, reducing the difficulty of operation.

[0028] In a preferred embodiment of this invention, the slider 2 has a semi-T-shaped structure. The slider 2 includes a connecting fitting guide part 21 and a driving limiting part 22. The fitting guide part 21 is located outside the groove 6, and the driving limiting part 22 is located inside the groove 6. The outer surface of the fitting guide part 21 is arc-shaped. In actual use, the outer surface of the fitting guide 21 is arc-shaped, which can fit tightly with the arc surface of the workpiece's inner hole, increasing the contact area while reducing local stress and avoiding damage to the workpiece's inner hole. At the same time, the arc-shaped structure can adapt to slight deviations in the size of different inner holes, ensuring the fit during fixing and improving clamping stability. The semi-T-shaped structure has the drive limiting part 22 located in the groove 6, which can slide stably along the inclined groove 5 of the groove 6, providing precise guidance for the overall movement of the slider 2. The fitting guide 21 is located outside the groove 6 and directly contacts the workpiece's inner hole. The two have a clear division of labor, ensuring that the slider 2 can adjust along the preset trajectory and reliably act on the workpiece's inner hole during movement. The fitting guide 21 and the drive limiting part 22 are connected as one unit. When the drive limiting part 22 is driven by the locking screw 3, the force can be directly transmitted to the fitting guide 21, so that the fitting guide 21 acts evenly on the workpiece's inner hole.

[0029] In a preferred embodiment of this invention, the drive limiting part 22 includes a mounting base 221 and two limiting blocks 222 symmetrically arranged at the bottom of the mounting base 221. A drive channel extending along the axial direction of the spindle 1 is formed between the relative inner sidewalls of the two limiting blocks 222. In actual use, the drive channel formed by the symmetrically arranged limiting blocks 222 provides a stable axial movement path for the screw 32 of the locking screw 3, ensuring that the screw 32 moves precisely along the axial direction of the spindle 1 during rotation adjustment, avoiding radial offset, thereby ensuring that the slider 2 can move smoothly along the inclined groove 5, achieving reliable fixation of the inner hole of the workpiece. The mounting base 221, as a structure connecting the fitting guide part 21 and the limiting blocks 222, can evenly transmit the force transmitted by the locking screw 3 through the drive channel to the fitting guide part 21. The limiting blocks 222 are symmetrically arranged. At the bottom of the mounting base 221, a structure similar to a support arm is formed, which can improve the overall rigidity of the drive limiting part 22, reduce the deformation generated during the tightening of the locking screw 3 or processing vibration, and ensure the dimensional stability of the drive channel. The formation of the drive channel is compatible with the screw 32, limiting ring 33 and other structures of the locking screw 3, providing the necessary space for the screw head 31 and the limiting ring 33 to engage with the limiting block 222, ensuring that the locking screw 3 can be flexibly adjusted in the drive channel and can effectively drive the slider 2 to move through the engagement relationship, realizing the adjustable function of the fixture.

[0030] In a preferred embodiment of this invention, the diameter of the driving channel is smaller than the diameter of the screw head 31 and the limiting ring 33, the diameter of the driving channel is larger than the diameter of the screw 32, and the radial dimension of the driving channel is larger than the diameter of the screw 32. The screw head 31 and the limiting ring 33 are located on both sides of the driving channel and are engaged with the limiting block 222. In actual use, the diameter of the drive channel is larger than the diameter of the screw 32, providing the screw 32 with room to move and ensuring that the screw 32 can move smoothly along the axial direction of the threaded hole when the locking screw 3 is rotated. The diameter of the drive channel is smaller than the diameter of the screw head 31 and the limiting ring 33, so that the screw head 31 and the limiting ring 33 can be respectively locked onto the limiting blocks 222 on both sides of the drive channel to form a bidirectional locking engagement. When the locking screw 3 is tightened, this locking engagement can convert the axial tension of the screw 32 into a driving force on the slider 2, driving the slider 2 to move along the groove 6 to fix the inner hole of the workpiece, ensuring effective force transmission and locking effect. The locking engagement between the screw head 31 and the limiting ring 33 and the limiting blocks 222 restricts the relative separation between the slider 2 and the locking screw 3, avoiding loosening or separation of the connection between the two due to vibration, force and other factors during processing, ensuring the stability of the fixture in fixing the workpiece, and reducing the risk of equipment failure or safety accidents caused by parts falling off.

[0031] In a preferred embodiment of this invention, the two limiting blocks 222 are provided with mounting holes facing each other, and anti-detachment pins 223 are provided at the mounting holes. The anti-detachment pins 223 are used to prevent the screw 32 from disengaging from the drive channel. In actual use, the anti-detachment pins 223 can effectively limit the axial movement of the screw 32 in the drive channel, avoiding accidental disengagement of the screw 32 from the drive channel due to vibration, impact or adjustment of the locking screw 3 during the processing. This ensures that the locking screw 3 and the slider 2 are always reliably engaged, maintaining the stable fixation of the workpiece by the fixture. Preventing the screw 32 from disengaging from the drive channel avoids equipment damage or personnel safety hazards caused by component detachment during clamping, adjustment or grinding, providing safety assurance for the entire processing flow. The anti-detachment pins 223 ensure that the screw 32 is always in the drive channel, so that the adjustment operation of the locking screw 3 can be accurately transmitted to the slider 2, ensuring that the alignment accuracy between the center of the workpiece inner hole and the axis of the mandrel 1 is not affected by component detachment.

[0032] In a preferred embodiment of this invention, a positioning ring 11 is provided in the middle of the shaft of the mandrel 1. The diameter of the positioning ring 11 is the same as the diameter of the raised ring 4. In actual use, the positioning ring 11 and the raised ring 4 have the same diameter, which can form a multi-point contact support with the inner hole of the workpiece. This provides an additional radial positioning reference when the workpiece is clamped, reducing the shaking caused by the long length of the workpiece or the tolerance of the inner hole, and improving the overall clamping stability. The central positioning ring 11 and the symmetrically arranged raised rings 4 form a structure similar to a three-point support, which enhances the overall deformation resistance of the mandrel 1. Especially when machining large bushings (such as large plunger sleeves for low-speed machines), it can reduce the bending or vibration of the mandrel 1 caused by force, ensuring machining accuracy. For workpieces with long inner hole lengths or intermediate positioning requirements, the positioning ring 11 can cooperate with the raised ring 4 to form a segmented support, adapting to the machining of workpieces with different inner hole structures and improving the versatility of the fixture.

[0033] In a preferred embodiment of this invention, the mandrel 1 has center holes 12 at both ends. In actual use, the center holes 12 can serve as positioning references during grinding, facilitating the fixing of the mandrel 1 with the grinding machine's center, ensuring that the mandrel 1 maintains a stable axial position during processing, providing reliable centering support for the external cylindrical grinding of the workpiece, and helping to improve the positional accuracy during processing. With the cooperation of the center holes 12 at both ends with the grinding machine's center, the axis of the mandrel 1 can be kept consistent with the axis of the grinding machine's spindle. Thus, through the fixed relationship between the mandrel 1 and the workpiece, the coincidence of the center of the workpiece's inner hole with the axis of the grinding machine's spindle is indirectly guaranteed, laying the foundation for achieving high coaxiality requirements in subsequent external cylindrical grinding. The center holes 12 can also serve as auxiliary positioning points during hoisting or transportation, facilitating the smooth movement and installation of the fixture containing the workpiece using special tools, improving the convenience and safety of operation.

[0034] Example 2: like Figures 1-7 As shown, based on Embodiment 1, this embodiment provides a method for machining an adjustable grinding mandrel fixture, which includes the following steps: S1: Place the adjustable grinding mandrel 1 fixture in the inner hole of the workpiece, and ensure that both ends of the mandrel 1 extend out of the inner hole of the workpiece by a preset distance. Then tighten the locking screw 3 to initially fix the slider 2 and the inner hole of the workpiece. S2: The entire fixture and workpiece are hoisted onto the grinding machine and fixed by the spindle 1. The inner hole of the workpiece is aligned by the dial indicator after initial fixing. The center of the inner hole of the workpiece is made to coincide with the axis of the spindle 1 by adjusting the locking screw 3, which facilitates the subsequent outer diameter grinding of the workpiece.

[0035] In actual use, the workpiece can be initially fixed by tightening the locking screw 3, without the need for complicated tooling replacement or adjustment, making the operation convenient. The workpiece is directly hoisted and fixed by the shaft of the mandrel 1, and the fine adjustment function of the locking screw 3 eliminates the tedious steps of repeatedly disassembling and assembling traditional fixtures and replacing wedges or mandrel 1, shortening the clamping and alignment time and improving the overall processing efficiency. By adjusting the locking screw 3 after alignment with the dial indicator, the center of the inner hole of the workpiece can be accurately aligned with the center of the mandrel 1. This solves the problem of unstable coaxiality after grinding the outer diameter of parts such as large plunger sleeves on low-speed machines, ensuring that the form and position accuracy of the inner hole and the outer diameter meet the requirements.

[0036] All technical features in this embodiment can be freely combined according to actual needs. The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

[0037] The above embodiments are preferred implementations of the present invention. In addition, other implementations are also included. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. An adjustable grinding mandrel fixture, characterized in that: The device includes a spindle (1), a slider (2), and a locking screw (3). The spindle (1) has a raised ring (4) on its shaft. The raised ring (4) has several inclined grooves (5) extending along the axial direction of the spindle (1). The inclined grooves (5) have grooves (6). One end of the groove (6) passes through the raised ring (4), and the other end of the groove (6) has a threaded hole. The slider (2) slides in the groove (6). The locking screw (3) passes through the slider (2) and forms a snap-fit ​​with the slider (2). The locking screw (3) extends into the groove (6) and is threadedly connected to the threaded hole. When the locking screw (3) is tightened, the slider (2) can move along the axial direction of the spindle (1) and fix the inner hole of the workpiece.

2. The adjustable grinding mandrel fixture according to claim 1, characterized in that: There are two raised rings (4), which are symmetrically distributed at both ends of the mandrel (1). The height of the inclined groove (5) gradually increases towards the center of the mandrel (1).

3. The adjustable grinding mandrel fixture according to claim 1, characterized in that: The locking screw (3) includes a screw head (31), a screw rod (32) and a limiting ring (33). The screw head (31) is integrally formed with one end of the screw rod (32), and the other end of the screw rod (32) is provided with an external thread. The limiting ring (33) is fixedly sleeved on the body of the screw rod (32).

4. The adjustable grinding mandrel fixture according to claim 3, characterized in that: The slider (2) has a semi-T-shaped structure. The slider (2) includes a connecting fitting guide (21) and a driving limiting part (22). The fitting guide (21) is located outside the groove (6), and the driving limiting part (22) is located inside the groove (6). The outer surface of the fitting guide (21) is arc-shaped.

5. The adjustable grinding mandrel fixture according to claim 4, characterized in that: The drive limiting part (22) includes a mounting base (221) and two limiting blocks (222) symmetrically arranged at the bottom of the mounting base (221). A drive channel extending along the axis of the spindle (1) is formed between the relative inner sidewalls of the two limiting blocks (222).

6. The adjustable grinding mandrel fixture according to claim 5, characterized in that: The diameter of the drive channel is smaller than the diameter of the screw head (31) and the limiting ring (33), the diameter of the drive channel is larger than the diameter of the screw (32), and the radial dimension of the drive channel is larger than the diameter of the screw (32). The screw head (31) and the limiting ring (33) are located on both sides of the drive channel and are engaged with the limiting block (222).

7. The adjustable grinding mandrel fixture according to claim 4, characterized in that: The two limiting blocks (222) are provided with mounting holes facing each other, and anti-detachment pins (223) are provided at the mounting holes to prevent the screw (32) from disengaging from the drive channel.

8. The adjustable grinding mandrel fixture according to claim 1, characterized in that: The mandrel (1) has a positioning ring (11) in the middle of its shaft, and the diameter of the positioning ring (11) is the same as the diameter of the raised ring (4).

9. The adjustable grinding mandrel fixture according to claim 1, characterized in that: Both ends of the mandrel (1) are provided with central holes (12).

10. A method for machining an adjustable grinding mandrel using a fixture, characterized in that, The machining of bushings using the adjustable grinding mandrel fixture as described in claims 1-9 includes the following steps: S1: Place the adjustable grinding mandrel fixture in the inner hole of the workpiece, and ensure that both ends of the mandrel (1) extend out of the inner hole of the workpiece by a preset distance. Then tighten the locking screw (3) to initially fix the slider (2) and the inner hole of the workpiece. S2: The entire fixture and workpiece are hoisted onto the grinding machine and fixed by the spindle (1). The inner hole of the workpiece is aligned by the dial indicator after initial fixing. The center of the inner hole of the workpiece is made to coincide with the axis of the spindle (1) by adjusting the locking screw (3), which facilitates the subsequent outer diameter grinding of the workpiece.

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