An outer circle grinding fixture for thin-walled parts and thin-walled parts

Abstract

The present application relates to a kind of thin-walled piece external grinding clamps and thin-walled piece.The thin-walled piece external grinding clamp includes: positioning body, positioning body has locating end face, and locating end face is formed with inner ring band and outer ring band for eliminating deformation rebound;Press block, it is sleeved on the positioning body, for the thin-walled piece to be processed is compressed.This application also provides a kind of thin-walled piece, using the thin-walled piece external grinding clamp described in the present application is clamped, and is obtained after external fine grinding processing.The present application solves the problem that existing common rail fuel injection inlet valve is prone to deformation and low precision in external fine grinding process.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to a grinding fixture for thin-walled parts and a thin-walled part. Background Technology

[0002] Marine common rail fuel injection pumps are precision-manufactured systems, and their key performance indicators must undergo rigorous quality control during production to ensure system reliability and consistency. If these key indicators are not controlled to the required standards, it may lead to malfunctions such as sliding joint jamming, pump failure, or even the complete failure of the fuel injection pump system.

[0003] Employing reliable tooling and fixtures to ensure control of key performance indicators during production is crucial for guaranteeing system quality stability. This is not only a necessary measure to ensure the performance of the fuel injection pump system, but also the foundation for maintaining the reliability of the entire system.

[0004] The fuel inlet valve, a core precision component in the common rail injection pump, primarily controls the entry of low-pressure fuel. It is a one-way valve that opens and closes by moving up and down. When the plunger moves downwards, the fuel inlet valve opens, allowing low-pressure fuel to flow into the plunger chamber; conversely, when the plunger moves upwards, the fuel inlet valve closes, stopping the flow of fuel and preventing backflow into the plunger chamber, thus ensuring the plunger chamber becomes a closed space and allowing fuel pressure to build up.

[0005] Since the inlet valve and the plunger sleeve together form a high-precision sliding pair, extremely high requirements are placed on the roundness and cylindricity of the outer diameter of the inlet valve. Simultaneously, the sealing surface formed by the large end face of the inlet valve and the lower end face of the outlet valve seat also needs to possess high dimensional and positional accuracy. Specific requirements include an outer diameter roundness of 0.001 mm, a cylindricity of 0.002 mm, an end face perpendicularity of 0.01 mm, and a coaxiality of 0.02 mm for the central bore.

[0006] This type of oil inlet valve is a high-hardness, thin-walled component with a wall thickness between 1 and 3 millimeters. During external cylindrical grinding, clamping can easily cause workpiece deformation, making it difficult to meet the accuracy requirements of the outer diameter and end face, directly affecting the performance of the assembly. Therefore, precision grinding of the outer diameter of the oil inlet valve has become a major technical challenge in the manufacturing of the entire pump assembly. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a grinding fixture for thin-walled parts and thin-walled parts, so as to solve the problems of easy deformation and low precision of the oil inlet valve of the existing common rail injection oil in the fine grinding process.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A grinding fixture for thin-walled parts includes: A positioning body having a positioning end face, wherein an inner ring band and an outer ring band are formed on the positioning end face for eliminating deformation and springback; The pressure block, fitted onto the positioning body, is used to press the thin-walled part to be processed.

[0009] Based on the above technical means, by forming inner and outer ring bands on the positioning end face to eliminate deformation springback, the micro-deformation at the micrometer (μ) level generated by grinding and clamping is offset by springback after disassembly, thereby avoiding deformation during fine grinding, improving the machining accuracy of thin-walled parts, and effectively solving the problems of easy deformation and low accuracy of the oil inlet valve of the existing common rail injection oil in the outer circle fine grinding process.

[0010] Preferably, the inner and outer ring bands are circumferential protrusions formed on the positioning end face.

[0011] Preferably, the protrusion of the inner ring band is greater than the protrusion of the outer ring band.

[0012] By limiting the protrusion of the inner ring to be greater than that of the outer ring, the problem of micro-deformation during grinding of thin-walled parts can be eliminated in reverse.

[0013] Because the workpiece is thin-walled and requires high roundness during grinding, it is extremely sensitive to deformation caused by grinding pressure. During grinding, the thin outer diameter undergoes a slight inward deformation due to the pressure from the grinding wheel. This inward springback occurs after grinding and the clamping is released. If there is no protrusion or the inner ring protrusion is lower than the outer ring protrusion, this springback cannot be eliminated or may even be exacerbated. Therefore, the inner ring protrusion needs to be greater than the outer ring protrusion to counteract the grinding micro-deformation.

[0014] Preferably, the protrusion L1 of the inner ring band is 0.3 to 0.5 mm; And / or, the protrusion L2 of the outer ring band is [L1-(0.0015~0.003)] mm.

[0015] Preferably, the width B1 of the inner ring band is 2.5 to 3 mm; And / or, the width B2 of the outer ring band is 3-4 mm; And / or, the outer edge diameter D1 of the inner ring is 1.8 to 1.9d, where d is the diameter of the centering section of the positioning body; And / or, the outer edge diameter D2 of the outer ring is 0.9 to 0.95D, where D is the outer diameter of the thin-walled part.

[0016] Preferably, the pressing block includes an inner ring pressing block and an outer ring pressing block; The inner ring pressure block is fitted onto the positioning body and is used to press the inner ring of the thin-walled part to be processed; The outer ring pressure block is fitted onto the positioning body and is used to press the outer ring of the thin-walled part to be processed.

[0017] By separately setting an inner ring clamping block for clamping the inner ring of the thin-walled part to be processed and an outer ring clamping block for clamping the outer ring of the thin-walled part to be processed, the inner and outer rings of the thin-walled part are clamped separately, ensuring the stability of the fixture in holding the thin-walled part to be processed and improving the processing accuracy. By setting the clamping blocks separately, the overall deformation of the thin-walled part during processing is effectively reduced. By setting the clamping blocks separately, the inner and outer ring clamping blocks can be adjusted independently, effectively adapting to thin-walled parts of different sizes and shapes. The separate clamping blocks can clamp the inner and outer rings simultaneously, effectively improving the processing speed. The separate design of the inner and outer ring clamping blocks facilitates maintenance and replacement of damaged parts.

[0018] Preferably, the inner ring pressure block is fixed by a first nut.

[0019] Preferably, the outer ring pressure block is fixed by a second nut.

[0020] Preferably, the inner ring pressure block has first protrusions arranged at intervals along its circumference.

[0021] Preferably, the outer ring pressure block is provided with second protrusions spaced apart along its circumference.

[0022] By cleverly using a method of arranging bosses at intervals to press certain parts of the inner and outer pressing surfaces of the thin-walled part to be processed, not only is the problem of large deformation caused by overall pressing avoided, but also the problem of unevenness in certain parts of the thin-walled part to be processed, which would reduce the overall pressing effect and affect the processing accuracy, is also avoided.

[0023] Preferably, the inner ring pressure block has three first protrusions spaced apart along its circumference.

[0024] Preferably, the inner ring pressure block has three first protrusions spaced apart along its circumference.

[0025] By cleverly arranging three first protrusions and three second protrusions evenly spaced on the inner and outer ring pressure blocks, the inner and outer pressure surfaces of the thin-walled parts to be processed are pressed respectively, ensuring the uniform distribution of the pressing force and ensuring the processing accuracy of the thin-walled parts.

[0026] Preferably, a positioning shaft extends from the positioning end face; The positioning shaft includes a centering section near the root of the positioning shaft and a threaded section away from the root of the positioning shaft; The end of the positioning shaft is provided with a first central hole.

[0027] Preferably, the positioning body has a second central hole on the end face away from the positioning axis.

[0028] By further extending the positioning end face to form a positioning shaft, and cleverly dividing the positioning shaft into a centering section and a threaded section, the centering section is used to achieve the center positioning of the thin-walled part to be machined, so that the center positioning and end face positioning of the thin-walled part to be machined are combined into one, which significantly improves the positioning accuracy and thus ensures the machining accuracy. At the same time, the threaded section provides convenience for the assembly of the nut.

[0029] The present invention also provides a thin-walled part, which is clamped by the thin-walled part outer cylindrical grinding fixture described in the present invention and obtained by precision grinding of the outer cylindrical part.

[0030] The beneficial effects of this invention are: The thin-walled part external cylindrical grinding fixture of the present invention forms an inner ring and an outer ring on the positioning end face to eliminate deformation springback. This allows the micron (μ) level micro-deformation generated by grinding clamping to be offset by springback after disassembly, thereby avoiding deformation during fine grinding, improving the machining accuracy of thin-walled parts, and effectively solving the problems of easy deformation and low accuracy of the oil inlet valve of the existing common rail injection oil in the external cylindrical fine grinding process. The entire fixture system has the advantages of high reliability, high control accuracy and simple structure, and has promotion and application value in the field of machining technology. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a grinding fixture for thin-walled parts. Figure 2 This is a schematic diagram of the positioning body. Figure 3 This is a schematic diagram of the inner ring pressure block. Figure 4 This is a right view of the inner ring pressure block; Figure 5 This is a schematic diagram of the outer ring pressure block. Figure 6 This is a right view of the outer ring pressure block; Figure 7 This is a schematic diagram of the structure of the first nut; Figure 8 This is a schematic diagram of the structure during grinding; Among them, 1-positioning body, 11-positioning end face, 12-inner ring belt, 13-outer ring belt, 14-positioning shaft, 141-centering section, 142-threaded section, 15-first center hole, 16-second center hole; 2-pressure block, 21-inner ring pressure block, 211-first boss, 212-guide hole, 22-outer ring pressure block, 221-second boss; 3-first nut; 4-second nut; 5-oil inlet valve to be processed; 6-drive clamp; 7-left center; 8-right center; 9-grinding wheel. Detailed Implementation

[0032] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0033] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0034] The present invention aims to disclose a grinding fixture for thin-walled parts and a thin-walled part, so as to solve the problems of easy deformation and low precision of the oil inlet valve of the existing common rail injection oil in the fine grinding process.

[0035] Among them, such as Figures 1 to 8 As shown, a grinding fixture for the outer diameter of a thin-walled part includes: Positioning body 1, the positioning body 1 has a positioning end face 11, and an inner ring band 12 and an outer ring band 13 are formed on the positioning end face 11 to eliminate deformation and springback; Pressure block 2 is fitted onto positioning body 1 and is used to press the thin-walled part to be processed.

[0036] Among them, the positioning body, as the foundation of the entire fixture, has a novel structural design. By setting a new structure of inner and outer ring belts on the positioning end face of the positioning body, the micro-deformation generated by grinding and clamping is eliminated through deformation springback.

[0037] In some embodiments, the inner ring band 12 and the outer ring band 13 are circumferential protrusions formed on the positioning end face 11.

[0038] In some embodiments, the protrusion of the inner ring band 12 is greater than the protrusion of the outer ring band 13.

[0039] In some embodiments, the protrusion L1 of the inner ring band 12 is 0.3 to 0.5 mm; The protrusion L2 of the outer ring 13 is [L1-(0.0015~0.003)] mm.

[0040] In some embodiments, the B1 of the inner ring band 12 is 2.5–3 mm; In some embodiments, the width B2 of the outer ring band 13 is 3 to 4 mm; In some embodiments, the outer edge diameter D1 of the inner ring band 12 is 1.8 to 1.9d, where d is the diameter of the centering segment 141 of the positioning body 1; In some embodiments, the outer edge diameter D2 of the outer ring band 13 is 0.9 to 0.95D, where D is the outer diameter of the thin-walled part.

[0041] The position and protrusion of the ring are designed, fine-tuned, and tested to correct the different wall thickness structures of the oil inlet valve.

[0042] In some embodiments, the pressure block 2 includes an inner ring pressure block 21 and an outer ring pressure block 22; The inner ring pressure block 21 is fitted onto the positioning body 1 and is used to press the inner ring of the thin-walled part to be processed; The outer ring pressure block 22 is fitted onto the positioning body 1 and is used to press the outer ring of the thin-walled part to be processed.

[0043] By separately setting an inner ring clamping block for clamping the inner ring of the thin-walled part to be processed and an outer ring clamping block for clamping the outer ring of the thin-walled part to be processed, the inner and outer rings of the thin-walled part are clamped separately, ensuring the stability of the fixture in holding the thin-walled part to be processed and improving the processing accuracy. By setting the clamping blocks separately, the overall deformation of the thin-walled part during processing is effectively reduced. By setting the clamping blocks separately, the inner and outer ring clamping blocks can be adjusted independently, effectively adapting to thin-walled parts of different sizes and shapes. The separate clamping blocks can clamp the inner and outer rings simultaneously, effectively improving the processing speed. The separate design of the inner and outer ring clamping blocks facilitates maintenance and replacement of damaged parts.

[0044] In some embodiments, the pressure block 2 includes an inner ring pressure block 21 and an outer ring pressure block 22; The inner ring pressure block 21 is fitted onto the positioning body 1 and is used to press the inner ring of the thin-walled part to be processed; The outer ring pressure block 22 is fitted onto the positioning body 1 and is used to press the outer ring of the thin-walled part to be processed.

[0045] By combining the inner and outer ring belts with the inner and outer ring pressure blocks, their synergistic effect effectively ensures the positioning and clamping effect, and guarantees precise and stable control of the external diameter grinding accuracy index.

[0046] Among them, the inner ring pressure block 21 is used for the inner ring pressing of the end face of the thin-walled part to be processed. The structural features are: (1) the precision control design of the guide hole and the end face. On the one hand, the diameter D3 of the guide hole 212 of the inner ring pressure block 21 and the outer diameter d of the centering section 141 of the positioning body 1 are fitted with a clearance of 0.01~0.015mm, that is, D3=[d+(0.01~0.015)]mm; on the other hand, the flatness of the end face of the inner ring pressure block 21 and the hole is optimized to meet the perpendicularity requirements of the guide hole. Through these two aspects, the accuracy and stability of the flat pressure generated by the tightening of the nut are ensured.

[0047] The outer ring pressure block 22 is used to press the outer ring of the end face of the thin-walled part to be processed, and its structural characteristics are basically the same as those of the inner ring pressure block 21. Through structural design, the deformation of the pressing outer ring is reduced.

[0048] In some embodiments, the inner ring pressure block 21 is fixed by the first nut 3; In some embodiments, the outer ring pressure block 22 is fixed by the second nut 4.

[0049] For example, both the first nut 3 and the second nut 4 are flat-pressure nuts.

[0050] The flat-pressure nut is a special nut. The end face of the flat-pressure nut that contacts the inner ring pressure block 21 has a countersunk hole 31, so that the contact surface between the flat-pressure nut and the inner ring pressure block 21 is a circle (not a whole surface), reducing the contact surface, forming a floating contact of the pressing surface, generating parallel thrust, reducing clamping deformation, and thus reducing clamping deformation of the thin-walled parts to be processed.

[0051] In some embodiments, the inner ring pressure block 21 is provided with first protrusions 211 spaced apart along its circumference; The outer ring pressure block 22 is provided with second protrusions 221 at intervals along its circumference; By cleverly using spaced bosses to press certain parts of the thin-walled part to be processed, not only is the problem of large deformation caused by overall pressing avoided, but also the problem of unevenness in certain parts of the thin-walled part to be processed, which reduces the overall pressing effect and affects the processing accuracy, is avoided.

[0052] In some embodiments, the inner ring pressure block 21 has three first protrusions 211 spaced apart along its circumference; The inner ring pressure block 21 has three first protrusions 211 arranged at intervals along its circumference.

[0053] By cleverly employing a three-point pressing end face design, the adverse effects of uneven pressing surfaces are reduced. The boss structure design also minimizes deformation of the inner pressing ring.

[0054] In some embodiments, a positioning shaft 14 extends from the positioning end face 11; The positioning shaft 14 includes a centering section 141 near the root of the positioning shaft 14 and a threaded section 142 away from the root of the positioning shaft 14.

[0055] By further extending the positioning end face to form a positioning shaft, and cleverly dividing the positioning shaft into a centering section and a threaded section, the centering section is used to achieve the center positioning of the thin-walled part to be machined, so that the center positioning and end face positioning of the thin-walled part to be machined are combined into one, which significantly improves the positioning accuracy and thus ensures the machining accuracy. At the same time, the threaded section provides convenience for the assembly of the nut.

[0056] For example, the end of the positioning shaft 14 is provided with a first central hole 15; A second center hole 16 is provided on the end face of the positioning body 1 away from the positioning shaft 14.

[0057] The centering and end-face positioning are integrated into the positioning body, thereby replicating the shape and position accuracy onto the thin-walled part to be processed, ensuring assembly accuracy and processing progress.

[0058] Specifically: on the one hand, the positioning body is designed and manufactured with a higher dimensional accuracy than that of the oil inlet valve; on the other hand, the outer diameter of the centering section of the positioning body is manufactured in stages according to the tolerance of the centering hole diameter of the oil inlet valve, and selected according to the minimum clearance during use to ensure reliable positioning, thereby copying the dimensional accuracy of the positioning body onto the grinding part.

[0059] At the same time, threaded sections for assembling the nut of the inner ring pressure block and the nut of the outer ring pressure block are formed on the positioning shaft, which effectively ensures the coaxiality control of the major diameter of the thread, facilitates the flat pressure guidance of the inner ring pressure block and the outer ring pressure block, and effectively reduces the compression deformation of thin-walled parts.

[0060] Taking the oil inlet valve as an example, as a thin-walled part to be processed, the thin-walled part outer diameter grinding fixture is used in actual use. First, the centering section 141 of the positioning body 1 is matched with the centering hole of the oil inlet valve according to the principle of minimum clearance. Then, the oil inlet valve 5 to be processed is placed on the positioning end face 11 of the positioning body 1. The inner ring of the oil inlet valve 5 to be processed is pressed by the inner ring pressure block 21 and locked by the flat pressure nut. The outer ring of the oil inlet valve 5 to be processed is pressed by the outer ring pressure block 22 and locked by the flat pressure nut. Then, the positioning body 1 is mounted on the drive clamp 6, and the left center point 7 is installed in the second center hole 16 of the positioning body 1, and the right center point 8 is installed in the first center hole 15. Then, the outer diameter of the oil inlet valve 5 to be processed is finely ground by the grinding wheel 9 to achieve fine grinding of the outer diameter of the thin-walled easily deformable part.

[0061] The oil inlet valve obtained after precision grinding was tested and found to have an outer circle roundness of 0.00035–0.0006 mm, a cylindricity of 0.0007–0.0012 mm, a perpendicularity to the end face of 0.005–0.008 mm, and a coaxiality to the center hole of 0.004–0.0065 mm, which meets the requirements for dimensional and positional accuracy. This proves that the fixture of the present invention can guarantee the dimensional and positional accuracy requirements of the outer circle of the oil inlet valve and improve the basic guarantee conditions for stable mass production of common rail injection pumps.

[0062] In some embodiments, a thin-walled part is also provided, which is clamped by a thin-walled part outer cylindrical grinding fixture according to any of the above embodiments and then subjected to fine grinding to obtain a thin-walled part.

[0063] In summary, the thin-walled part external cylindrical grinding fixture of the present invention, firstly, by forming inner and outer ring bands on the positioning end face to eliminate deformation springback, ensures that the micron (μ) level micro-deformation generated by grinding clamping is offset by springback after disassembly, thereby avoiding deformation during fine grinding, improving the machining accuracy of thin-walled parts, and effectively solving the problems of easy deformation and low accuracy of existing common rail injection oil inlet valves during external cylindrical fine grinding; secondly, by integrating the centering and end face positioning of the positioning body, the dimensional accuracy of the positioning body is copied onto the workpiece, effectively ensuring assembly accuracy, thereby ensuring machining accuracy; thirdly, by setting inner and outer ring pressure blocks respectively, the clamping deformation of thin-walled parts is reduced; the entire fixture system has the advantages of high reliability, simple structure, and high control accuracy, and has promotion and application value in the field of machining technology.

[0064] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A grinding fixture for the outer cylindrical section of a thin-walled part, characterized in that, include: Positioning body (1), the positioning body (1) has a positioning end face (11), the positioning end face (11) is formed with an inner ring band (12) and an outer ring band (13) for eliminating deformation and springback. The pressure block (2) is fitted onto the positioning body (1) and is used to press the thin-walled part to be processed; the inner ring band (12) and the outer ring band (13) are circumferential protrusions formed on the positioning end face (11); the protrusion of the inner ring band (12) is greater than the protrusion of the outer ring band (13); The pressure block (2) includes an inner ring pressure block (21) and an outer ring pressure block (22); The inner ring pressure block (21) is fitted onto the positioning body (1) and is used to press the inner ring of the thin-walled part to be processed; The outer ring pressure block (22) is fitted onto the positioning body (1) and is used to press the outer ring of the thin-walled part to be processed.

2. The thin-walled part external cylindrical grinding fixture according to claim 1, characterized in that, The protrusion L1 of the inner ring band (12) is 0.3 to 0.5 mm; And / or, the protrusion L2 of the outer ring band (13) is [L1-(0.001~0.003)] mm.

3. The thin-walled part external cylindrical grinding fixture according to claim 1, characterized in that, The width of the inner ring band (12) is 2.5-3 mm; And / or, the width of the outer ring band (13) is 3 to 4 mm; And / or, the outer edge diameter of the inner ring (12) is 1.4 to 1.5d, where d is the diameter of the centering segment (141) of the positioning body (1); And / or, the outer edge diameter of the outer ring (13) is 0.9 to 0.95D, where D is the outer diameter of the thin-walled part to be processed.

4. The thin-walled part external cylindrical grinding fixture according to claim 1, characterized in that, The inner ring pressure block (21) is fixed by the first nut (3); And / or, the outer ring pressure block (22) is fixed by a second nut (4).

5. The thin-walled part external cylindrical grinding fixture according to claim 1, characterized in that, The inner ring pressure blocks (21) are arranged at intervals along the circumferential direction of the thin-walled part to be processed; And / or, the outer ring pressure blocks (22) are arranged at intervals along the circumferential direction of the thin-walled part to be processed; And / or, the inner ring pressure block (21) is provided with first bosses (211) spaced apart along its circumference. And / or, the outer ring pressure block (22) is provided with second bosses (221) spaced apart along its circumference.

6. The thin-walled part external cylindrical grinding fixture according to claim 1, characterized in that, A positioning shaft (14) extends from the positioning end face (11). The positioning shaft (14) includes a centering section (141) near the root of the positioning shaft (14) and a threaded section (142) away from the root of the positioning shaft (14). The end of the positioning shaft (14) is provided with a first center hole (15). And / or, the positioning body (1) has a second center hole (16) on the end face away from the positioning shaft (14).

7. A thin-walled component, characterized in that, The thin-walled part is held in a grinding fixture as described in any one of claims 1 to 6 and then precision ground on its outer diameter.

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