Outer circle grinding method and device for non-full-circle slender shaft part

Abstract

An outer circle grinding method and device for a non-full-circle slender shaft part are used for machining a workpiece, and the cross section of the workpiece is non-full-circle. The device comprises a plurality of filling pieces used for filling a non-full-circle area in the middle of the workpiece, so that the non-full-circle area forms a continuous full-circle bracket position; the bearing end of the center frame is matched with the rounding bracket position, and the center frame is used for supporting the workpiece in the grinding process. The device is used for manufacturing a center frame bracket position, mounting of a center frame is achieved, the rigidity and stability of a workpiece are enhanced, one-time grinding machining forming of an outer circle is achieved, and the device is simple in design, convenient to operate, wide in application range and suitable for outer circle grinding machining of various special-shaped long shaft parts.

Description

Technical Field

[0001] This invention belongs to the field of non-circular component processing technology, and specifically relates to a method and apparatus for grinding the outer diameter of non-circular slender shaft parts. Background Technology

[0002] In the field of precision machining, slender shaft parts, due to their large length-to-diameter ratio and poor rigidity, are prone to bending deformation and vibration during external cylindrical grinding. A center rest is typically required to provide central support and improve the rigidity of the machining system. However, for slender shaft parts with non-circular cross-sections (such as those with notches, flat sections, or irregular contours), the lack of a continuous circular surface on the outer diameter makes it impossible to directly install a standard center rest, severely restricting the realization of high-precision grinding.

[0003] Existing solutions mainly include two types: one is to use a segmented grinding process to avoid non-circular areas, but this cannot guarantee the dimensional consistency and straightness of the entire outer circle; the other is to add a stainless steel transition bushing to form a temporary support surface, but the bushing itself will interfere with the grinding wheel, still requiring segmented machining, and the fit clearance between the bushing and the workpiece and the difference in thermal deformation can easily introduce new error sources, making it difficult to meet the 0.02mm level outer circle dimensional tolerance and straightness requirements. Therefore, there is an urgent need for a special tooling that can provide effective support without affecting continuous grinding in one go, to solve the technical problem of high-precision outer circle machining of non-circular slender shafts. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and apparatus for grinding the outer diameter of non-circular slender shaft parts, so as to prepare a center support bracket position, realize the installation of the center support, enhance the rigidity and stability of the workpiece, and achieve one-time grinding and forming of the outer diameter. The apparatus is simple in design, convenient to operate, and has a wide range of applications, and is suitable for grinding the outer diameter of various irregular long shaft parts.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for grinding the outer diameter of a non-circular slender shaft part, used for machining workpieces with a non-circular cross-section, includes the following steps: A filler is installed in the non-circular area in the middle of the workpiece to form a continuous circular bracket position; The workpiece is clamped on an external cylindrical grinding machine; The circular bracket position is ground to form a high-precision circular support surface; The support end of the center frame is matched with the ground round bracket position to provide central support for the workpiece; The target outer circle of the workpiece and the full-circle bracket position are simultaneously precision ground to achieve one-time forming processing.

[0006] The filler is bonded and fixed to the workpiece with epoxy resin strong structural adhesive.

[0007] The filler is made of a non-metallic material; the non-metallic material is phenolic resin.

[0008] This method also includes: controlling the contact gap between the support end and the circular bracket position by adjusting the adjustment mechanism on the central frame; In the step of simultaneously fine grinding the workpiece, the following grinding parameters are used: (1) The linear velocity of the workpiece is 3 m / min; (2) The table moving speed is 0.6 m / min; (3) The grinding depth is 0.005 mm; After the workpiece has been synchronously fine-ground, the filler is removed.

[0009] A grinding apparatus for the outer diameter of a non-circular slender shaft part, used for machining the workpiece, the workpiece having a non-circular cross-section; the apparatus includes: Multiple fillers are used to fill the non-circular area in the middle of the workpiece, so that the non-circular area forms a continuous circular bracket position; The center frame, whose supporting end mates with the circular bracket, is used to support the workpiece during the grinding process.

[0010] As a preferred embodiment, the circular bracket position is an annular area on the workpiece used for mounting the filler.

[0011] As a preferred embodiment, the filler is made of phenolic resin and is bonded to a non-circular area in the center of the workpiece using structural adhesive. As a preferred embodiment, the phenolic resin material is a high-strength phenolic resin bakelite board.

[0012] As a preferred embodiment, the central frame is provided with longitudinal adjusting screws and transverse adjusting screws for adjusting the contact gap between the support end of the central frame and the circular bracket position.

[0013] As a preferred embodiment, a longitudinal adjusting screw mounting plate and a transverse adjusting screw mounting plate are installed on the center frame, wherein the longitudinal adjusting screws are mounted on the longitudinal adjusting screw mounting plate and the transverse adjusting screws are mounted on the transverse adjusting screw mounting plate.

[0014] As a preferred embodiment, the workpiece is clamped on the external cylindrical grinding machine in a double-top manner through the ejector pin holes at both ends.

[0015] As a preferred embodiment, the structural adhesive is a high-strength epoxy resin structural adhesive.

[0016] The present invention can achieve the following beneficial effects: 1. This device enables continuous grinding of non-circular slender shafts in a single clamping operation. By coaxially mounting a split support sleeve on the outer circumference of the non-circular section of the workpiece, a complete circular support surface is formed, allowing the center frame roller to make stable contact and provide central support. This avoids the multiple clamping and processing interruptions caused by traditional segmented grinding or bushing interference, ensuring the consistency of the outer circle's overall dimensions and straightness.

[0017] 2. This device has a simple structure, precise positioning, and convenient assembly and disassembly. The support sleeve adopts a two-half structure that splits along the axial direction. The inner contour is precisely matched with the non-circular section of the workpiece. It naturally hugs itself by its own weight and the centrifugal force of the grinding machine rotation, without the need for additional fasteners. Its outer circle serves as a standard support surface, which fits well with the center frame roller, effectively improving the rigidity of the process system and suppressing grinding vibration and bending deformation.

[0018] 3. Without changing the existing grinding machine configuration, this device solves the technical bottleneck that non-circular slender shafts cannot use a center rest. The external cylindrical grinding dimensional tolerance and straightness can be stably controlled within 0.02mm. At the same time, it eliminates auxiliary processes such as transition bushing installation, repair and secondary tool setting, which greatly improves processing efficiency and product qualification rate.

[0019] 4. The grinding accuracy of the outer diameter of this device reaches 0.01mm / length, fully meeting and exceeding the design requirements. Straightness reaches 0.01mm / length, better than the design requirements. Due to the reinforced workpiece structure, machining deformation is small, and machining efficiency is increased by 50%. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is the front view of the present invention; Figure 2 This is a three-dimensional rendering of the present invention; Figure 3 This is a flowchart of the processing of the present invention.

[0021] In the diagram: 1. Workpiece; 2. Grinding wheel; 3. Phenolic resin bracket; 4. Center frame; 5. Longitudinal adjusting screw; 6. Lateral adjusting screw; 7. Longitudinal adjusting screw mounting plate; 8. Lateral adjusting screw mounting plate. Detailed Implementation

[0022] like Figures 1 to 3 As shown, the present invention provides an external cylindrical grinding device for non-circular slender shaft parts, used to process workpieces 1 with non-circular cross-sections. The workpiece 1 is typically a slender shaft part with a length greater than 1000mm, a small diameter (e.g., around 20mm), and poor rigidity. Its outer diameter needs to meet high-precision dimensional tolerances (±0.01mm) and overall straightness requirements (≤0.02mm).

[0023] This device includes multiple filler elements 2 and a center support 4. The filler elements 2 are configured to fill the non-circular area in the center of the workpiece 1, transforming the originally discontinuous contour into a continuous circular support position. The support end of the center support 4 cooperates with this circular support position, providing central support for the workpiece 1 during external cylindrical grinding, effectively suppressing vibration and bending deformation. In this embodiment, the number of filler elements 2 is six.

[0024] As a specific optional solution, the full-circle bracket position refers to a ring-shaped area on the workpiece 1 specifically used for installing the filler 2. This area is located in the middle of the workpiece 1 and has a certain width along the axial direction to ensure the stable support of the center frame 4.

[0025] As a specific optional solution, the filler 2 is made of phenolic resin material and is bonded to the non-circular notch in the middle of the workpiece 1 with structural adhesive. Preferably, the phenolic resin material is a high-strength phenolic resin bakelite board, which has good mechanical strength, dimensional stability and easy processing, while having moderate hardness, facilitating subsequent grinding and shaping, and will not damage the workpiece substrate.

[0026] As a specific optional solution, the structural adhesive is preferably a strong epoxy resin structural adhesive. This adhesive has advantages such as high shear strength, good oil and temperature resistance, and low shrinkage after curing, which can ensure that the filler 2 is firmly attached to the surface of the workpiece 1 during the grinding process, without falling off or shifting.

[0027] As a specific optional solution, the center frame 4 is equipped with a longitudinal adjusting screw 5 and a transverse adjusting screw 6 for finely adjusting the contact gap between the support end of the center frame 4 and the circular bracket position, ensuring a close fit without over-positioning. More specifically, the center frame 4 is also equipped with a longitudinal adjusting screw mounting plate 7 and a transverse adjusting screw mounting plate 8. The longitudinal adjusting screw 5 is mounted on the longitudinal adjusting screw mounting plate 7, and the transverse adjusting screw 6 is mounted on the transverse adjusting screw mounting plate 8, thereby providing a stable installation reference and precise adjustment freedom for the adjustment mechanism.

[0028] Alternatively, this device can be replaced by other equivalent structures: The workpiece 1 is clamped on the cylindrical grinding machine using a double-clamping method through pre-machined ejector pin holes at both ends. This clamping method ensures that the rotation axis of the workpiece 1 is coaxial with the grinding machine spindle, providing a basic condition for high-precision grinding.

[0029] In practice, firstly, based on the geometry of the non-circular cross-section of workpiece 1, multiple high-strength phenolic resin bakelite board fillers 2 are machined using CNC equipment to match it. Then, epoxy resin strong structural adhesive is used to bond the fillers 2 to the corresponding notch position in the middle of workpiece 1. After the adhesive layer has completely cured, workpiece 1 is clamped on an external cylindrical grinding machine in a double-top manner, and the bonded filling area is precisely ground with a grinding wheel to form a circular support position with a runout of less than 0.005mm. Next, the center support 4 is moved below the support position, and the position of the support end is finely adjusted by the longitudinal adjusting screw 5 and the transverse adjusting screw 6 to control the gap within 0.005mm. Finally, synchronous fine grinding is performed, and high-precision external cylindrical machining can be completed in one go.

[0030] After processing, filler 2 can be easily removed by soaking in a solvent (such as acetone). The surface of workpiece 1 is undamaged and has no residue, meeting the requirements for subsequent assembly or use.

[0031] In summary, this invention solves the technical problem of high-precision grinding of such parts due to the lack of effective support by constructing a grindable and removable full-circle support position in the middle of a non-full-circle slender shaft and cooperating with a precision-adjustable center frame. It has significant advantages such as simple structure, low cost, convenient operation and high precision.

[0032] The specific operation steps of this embodiment are as follows: Step 1: Preparation of filler 2 First, a three-dimensional scan of the non-circular cross-section of the area to be supported in the middle of workpiece 1 is performed using precision equipment such as a coordinate measuring machine to obtain its precise geometric contour data. Based on this data, high-strength phenolic resin bakelite board is selected as the raw material and multiple filler parts 2 are precisely machined on a CNC machining center to perfectly match the non-circular gaps of workpiece 1. In this embodiment, there are 6 gaps in the cross-section of workpiece 1, so 4 filler parts 2 are machined to fill them and form a complete circle.

[0033] Step 2: Adhere filler 2 The pre-machined filler 2 and the non-circular area of ​​workpiece 1 are cleaned to ensure that the contact surfaces are free of oil and oxides. Then, using a strong epoxy structural adhesive, filler 2 is firmly bonded to the corresponding notch in the center of workpiece 1. After bonding, the assembly is placed in a constant temperature environment for full curing to ensure sufficient bond strength to withstand the cutting forces during subsequent grinding.

[0034] Step 3: Grind the round bracket position After the structural adhesive has completely dried and reached its designed strength, the workpiece 1 with the bonded filler 2 is clamped on an external cylindrical grinding machine. At this time, the ejector pin holes at both ends of the workpiece 1 have been pre-ground to ensure that their coaxiality is better than 0.01mm. The workpiece 1 is fixed by a double ejector pin clamping method. The grinding machine is started, and the grinding wheel 3 is used to perform precision grinding on the bonded phenolic resin filler 2, grinding its outer circle to a smooth transition with the original outer circle of the workpiece 1, ultimately forming a continuous and high-precision circular support position with a runout of less than 0.005mm.

[0035] Step 4: Install center frame 4 and adjust Move the standard grinding machine's center rest 4 below the pre-ground circular support position. The support end of the center rest 4 (usually three adjustable support claws) mates with the outer circle of the circular support position. Finely adjust the contact gap between the support end and the support position by adjusting the longitudinal adjusting screw 5 and the transverse adjusting screw 6 on the center rest 4 until the gap is less than 0.005mm, ensuring stable support and preventing over-positioning or excessive gap. The longitudinal and transverse adjusting screws are respectively mounted on dedicated longitudinal adjusting screw mounting plates 7 and 8 to provide a stable adjustment reference.

[0036] Step 5: Simultaneous precision grinding and shaping After the center rest 4 is precisely adjusted, the final fine grinding of the target outer diameter of workpiece 1 can begin. During this process, the center rest 4 provides crucial central support for the slender workpiece 1 through the full-circle support position, greatly enhancing its overall rigidity and effectively suppressing bending deformation and vibration during grinding. Ultimately, the outer diameter dimensional accuracy and overall straightness of workpiece 1 both reach 0.01mm, fully meeting or even exceeding the design requirements.

[0037] Step Six: Disassembly and Cleaning After processing, workpiece 1 is removed from the grinding machine. The bonding area is then soaked in organic solvents such as acetone, effectively dissolving the strong epoxy structural adhesive and allowing filler 2 to easily detach. Because the phenolic resin material has moderate hardness and a controllable difference in thermal expansion coefficient with the stainless steel substrate, workpiece 1 has no residue or damage on its surface after disassembly and can proceed directly to the next process.

[0038] In summary, this invention successfully solves the technical challenges of effectively supporting non-circular, slender shaft parts and making high-precision grinding difficult by ingeniously utilizing high-strength phenolic resin fillers to construct temporary support positions and combining them with a precision-adjustable center frame. This solution is simple in design, convenient to operate, low in cost, and significantly improves processing efficiency, making it valuable for a wide range of engineering applications.

[0039] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for grinding the outer diameter of a non-circular slender shaft part, used for machining a workpiece (1) with a non-circular cross-section, characterized in that, Includes the following steps: A filler (2) is installed in the non-circular area in the middle of the workpiece (1) to form a continuous circular bracket position; The workpiece (1) is clamped on an external cylindrical grinding machine; The circular bracket position is ground to form a high-precision circular support surface; The support end of the center frame (4) is matched with the ground round bracket to provide central support for the workpiece (1); The target outer circle and the whole circle bracket position of the workpiece (1) are simultaneously finely ground to achieve one-time forming processing.

2. The method for grinding the outer diameter of a non-circular slender shaft part according to claim 1, characterized in that, The filler (2) is bonded to the workpiece (1) by epoxy resin strong structural adhesive.

3. The method for grinding the outer diameter of a non-circular slender shaft part according to claim 1, characterized in that, The filler (2) is made of a non-metallic material; the non-metallic material is phenolic resin.

4. The method for grinding the outer diameter of a non-circular slender shaft part according to claim 1, characterized in that, By adjusting the adjustment mechanism on the central frame (4), the contact gap between its support end and the whole circular bracket position can be controlled; In the step of simultaneously fine grinding the workpiece (1), the following grinding parameters are used: (1) The linear velocity of the workpiece is 3 m / min; (2) The table moving speed is 0.6 m / min; (3) The grinding depth is 0.005 mm; After the synchronous fine grinding of the workpiece (1) is completed, the filler (2) is removed.

5. An external cylindrical grinding apparatus for a non-circular slender shaft part, used to perform the external cylindrical grinding method for a non-circular slender shaft part according to any one of claims 1-4, the apparatus being used to process a workpiece (1) whose cross-section is non-circular; characterized in that, The device includes: Multiple fillers (2) are used to fill the non-circular area in the middle of the workpiece (1) so that the non-circular area forms a continuous circular bracket position; The center frame (4) has its supporting end cooperating with the full-circle bracket position to support the workpiece (1) during the grinding process.

6. The external cylindrical grinding apparatus for non-circular slender shaft parts according to claim 5, characterized in that, The circular bracket position is an annular area on the workpiece (1) used for installing the filler (2).

7. The external cylindrical grinding apparatus for non-circular slender shaft parts according to claim 1, characterized in that, The filler (2) is made of phenolic resin material and is bonded to the non-circular area in the middle of the workpiece (1) by structural adhesive; The phenolic resin material is a high-strength phenolic resin bakelite board.

8. The external cylindrical grinding apparatus for non-circular slender shaft parts according to claim 5, characterized in that, The center frame (4) is provided with a longitudinal adjusting screw (5) and a transverse adjusting screw (6) for adjusting the contact gap between the support end of the center frame (4) and the circular bracket position.

9. The external cylindrical grinding apparatus for non-circular slender shaft parts according to claim 5, characterized in that, A longitudinal adjusting screw mounting plate (7) and a transverse adjusting screw mounting plate (8) are installed on the center frame (4). The longitudinal adjusting screw (5) is installed on the longitudinal adjusting screw mounting plate (7), and the transverse adjusting screw (6) is installed on the transverse adjusting screw mounting plate (8).

10. The external cylindrical grinding apparatus for non-circular slender shaft parts according to claim 1, characterized in that, The workpiece (1) is clamped on the external cylindrical grinding machine in a double-top manner through the pin holes at both ends.

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