An adjustable precision internal hole polishing device

Abstract

This invention belongs to the field of machining technology and relates to an adjustable precision internal hole polishing device. The expansion sleeve is cylindrical with a tapered hole machined in its center. The expansion sleeve is divided into N segments circumferentially. A polishing sleeve is provided outside the expansion sleeve. The expansion shaft consists of a long shaft section, a tapered section, and a threaded section from top to bottom. The tapered section of the expansion shaft mates with the tapered hole of the expansion sleeve. The radial expansion or contraction of the expansion sleeve is controlled by the axial up-and-down movement of the expansion shaft relative to the expansion sleeve, thereby adjusting the radial dimension of the polishing sleeve. The upper end face of the expansion sleeve has an upper fixed plate receiving hole, and the lower end face of the expansion sleeve has a lower fixed plate receiving hole. Each segment of the expansion sleeve has a through hole. The upper fixed plate has N screw through holes, and the lower fixed plate has N threaded holes. The N screws pass through the upper fixed plate, the expansion sleeve, and the lower fixed plate in sequence, thereby fixing the upper and lower fixed plates and the expansion sleeve. The center of the lower fixed plate has a threaded adjustment hole, which mates with the threaded section of the expansion shaft to control the radial dimension adjustment of the polishing sleeve.

Description

Technical Field

[0001] This invention belongs to the field of machining technology and relates to an adjustable precision internal hole polishing device. Background Technology

[0002] In aerospace hydraulic transmission products, the precision inner surfaces of piston cylinder parts are finished to improve dimensional and shape accuracy and reduce surface roughness. Previously, this was achieved through grinding with cast iron abrasive sleeves and manual polishing using a wooden handle wrapped with polishing paper or cloth and then applying polishing compound. Grinding with cast iron abrasive sleeves requires a high level of operator skill, but cast iron has almost no elasticity, making it easy to scratch the machined surface when inserting the abrasive into the workpiece and removing it after polishing. Manual polishing with a wooden handle wrapped with polishing paper or cloth and applying polishing compound is also problematic due to significant human error; it's difficult to apply even force, resulting in an unstable machined surface. This method is inefficient and physically demanding for workpieces with large holes or high aspect ratios. Summary of the Invention

[0003] The purpose of this invention is to provide an adjustable precision internal hole polishing device. This device allows for diameter adjustment and flexible contact with the internal hole, thus achieving the polishing requirements for precision internal holes.

[0004] The technical solution of this invention is as follows:

[0005] An adjustable precision internal hole polishing device, the device comprising: an expansion shaft, an expansion sleeve, a polishing sleeve, an upper fixed plate, a lower fixed plate, and fixing screws;

[0006] The expansion sleeve is cylindrical, with a tapered hole machined in the center, and is divided into N lobes along the circumference; a polished sleeve is provided on the outside of the expansion sleeve;

[0007] The expansion shaft consists of a long shaft section, a tapered section, and a threaded section from top to bottom. The tapered section of the expansion shaft mates with the tapered hole of the expansion sleeve. The radial expansion or contraction of the expansion sleeve is controlled by the axial up-and-down movement of the expansion shaft relative to the expansion sleeve, thereby adjusting the radial dimension of the polishing sleeve.

[0008] The upper end face of the expansion sleeve is provided with an upper fixed plate receiving hole, and the lower end face of the expansion sleeve is provided with a lower fixed plate receiving hole. Each segment of the expansion sleeve is provided with a through hole. The upper fixed plate is provided with N screw through holes, and the lower fixed plate is provided with N threaded holes. N screws pass through the upper fixed plate, the expansion sleeve and the lower fixed plate in sequence, thereby fixing the upper and lower fixed plates and the expansion sleeve.

[0009] The lower fixed plate is provided with a threaded adjustment hole at its center. The threaded adjustment hole cooperates with the threaded section of the expansion shaft to control the radial dimension adjustment of the polishing sleeve.

[0010] Furthermore, a hollow groove is provided between the end faces of the threaded section and the tapered section. The axial length of the hollow groove and the axial length of the threaded section constitute the maximum range of axial movement adjustment of the expansion shaft relative to the expansion sleeve.

[0011] Furthermore, the cone angle of the tapered section of the expansion shaft is 10° to 15°.

[0012] Furthermore, the polishing sleeve is manufactured in the following manner:

[0013] A cylindrical mold is placed concentrically outside the expansion sleeve. Rubber is injected between the mold and the expansion sleeve and vulcanized, so that the polishing sleeve and the expansion sleeve are integrated. After vulcanization, the rubber is shaped to adjust the working surface size of the polishing sleeve.

[0014] Furthermore, during the manufacturing of the polishing sleeve, the rubber intruding into the gaps between the N segments of the expansion sleeve is reshaped, and the length of the polishing sleeve intruding into the gaps is adjusted, thereby adjusting the elasticity of the device.

[0015] Furthermore, the expansion sleeve is divided into segments by radial cutting grooves, and each radial cutting groove passes through the axis of the expansion sleeve.

[0016] Furthermore, the expansion sleeve is divided into N equal parts, where N ≥ 3.

[0017] Furthermore, the expansion sleeve is not unequally divided into N segments, where N≥4.

[0018] Furthermore, the diameter of the through hole in each segment of the expansion sleeve is 0.5mm to 0.8mm larger than the screw diameter.

[0019] Furthermore, the outer surface of the polishing sleeve serves as the working surface, where abrasive is coated or adhered to polish the surface to be polished.

[0020] The beneficial effects of this invention are:

[0021] This application proposes an adjustable precision internal hole polishing device. The polishing head uses a soft material as its base to hold the polishing material, ensuring simple and reliable material clamping. An expansion device is installed inside the polishing head, allowing for free adjustment of expansion and contraction, enabling finishing processes for different hole diameters. It is suitable for... Polishing of through holes or blind holes.

[0022] This device utilizes flexible polishing. During polishing, the elastic polishing head expands and deforms the flexible polishing sleeve, creating a large-area conformal contact with the inner hole surface. It actively adapts to changes in the curvature of the inner hole surface. Simultaneously, polishing material is wound around the outer circumference of the polishing head, gently contacting the machined surface under the elastic force of the rubber. This effectively avoids the hard contact caused by rigid tools and scratches resulting from uneven abrasive distribution, ensuring uniform polishing removal and achieving precision machining. The device achieves a surface roughness of Ra0.05-Ra0.4. By combining different material heat treatment hardness and inner hole surface treatment methods, the polishing roughness is reduced by 50-60% compared to the original roughness. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings will be described below.

[0024] Figure 1 An isometric view of an adjustable precision internal hole polishing device;

[0025] Figure 2 A cross-sectional view of an adjustable precision internal hole polishing device;

[0026] Figure 3 Exploded view of a component in an adjustable precision internal hole polishing device;

[0027] Figure 4 This is a schematic diagram of the expansion sleeve structure;

[0028] Figure 5 This is a schematic diagram of the polishing sleeve structure. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0030] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0031] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0032] This embodiment provides an adjustable precision internal hole polishing device. By adjusting the device, it achieves finishing of different hole diameters. Simultaneously, the elastic polishing structure ensures gentle surface contact and uniform removal of excess material. It can achieve precision surface polishing of internal hole structural parts made of various materials (structural steel, stainless steel, copper, aluminum, non-metals, etc.). The surface roughness is significantly reduced and the shape accuracy is greatly improved after fine polishing. This device features adjustable processing dimensions, elastic contact, uniform force distribution, flexible operation, and low cost, meeting the high precision requirements of precision parts' internal holes and the technical requirements of sealing components.

[0033] Please see Figure 1-3 As shown in the figure, this embodiment provides an adjustable precision internal hole polishing device, including an expansion shaft 1, an upper fixed plate 2, a lower fixed plate 3, an expansion sleeve 4, a polishing sleeve 5, and a fixing screw 6.

[0034] The expansion shaft 1 is connected to the clamping part of the machine tool to achieve rotation. The expansion shaft 1 and the expansion sleeve 4 are connected with a tapered joint. The expansion sleeve 4 is designed to expand on all four sides. The expansion shaft 1 is fixed to the expansion sleeve 4 and the expansion shaft 1 through the screw holes on the upper fixed plate 2 and the lower fixed plate 3 with fixing screws 6. The expansion shaft 1 and the lower fixed plate 3 are connected by threads, and the expansion and contraction of the expansion sleeve 4 is adjusted by the thread feed. As the thread feed of the expansion shaft is adjusted, the expansion sleeve 4 will expand and contract in the circumferential direction, compressing the expansion and contraction of the elastic polishing sleeve 5. Tightening the fixing screws 6 achieves the expansion sleeve 4, the expansion shaft 1 and the polishing sleeve 5 are tightly fixed. The expansion of the polishing sleeve 5 is achieved by finely adjusting the thread depth at one end of the expansion shaft, realizing flexible contact with the inner hole surface for inner surface polishing.

[0035] For the expansion sleeve 4, please refer to Figure 4 As shown, the expansion sleeve 4 is equally divided in the circumferential direction. Four equally divided grooves are cut through the center point of the expansion sleeve. The minimum division of the expansion sleeve 4 is three equal parts, and the maximum is allocated as needed when the working diameter increases. When the number of cuts is odd, they must be equally divided; when it is even, they can be unequally divided. The groove width is 2-3mm. When the working diameter is small, the groove width can be around 3mm for easy size adjustment. Conversely, as the size increases, the expansion sleeve is prone to deformation, and the groove width gradually decreases. Screw fixing holes are evenly distributed on the end face of the expansion sleeve 4. The screw hole size is 0.5-0.8mm larger than the screw size, allowing for a 0.5-0.8mm shrinkage space in the circumference of the expansion sleeve as it expands and contracts with the expansion shaft. The expansion sleeve material can be copper, aluminum, steel, etc., without specific requirements. The fixing screws 6 clamp the entire polishing sleeve 5 by fixing the upper fixing plate 2 and the lower fixing plate 3 through the screw holes.

[0036] For the expansion shaft 1, please refer to Figure 3As shown, the expansion shaft 1 is the connecting component of this device. The material should be selected to withstand wear from repeated adjustments and to support the entire mechanism; therefore, medium carbon steel or higher should be used, and its strength should be improved through heat treatment. The outer taper of the expansion shaft 1 matches the inner taper hole of the expansion sleeve 4, and the expansion sleeve 4 expands as the expansion shaft 1 moves. One end of the expansion shaft 1 is connected to the lower fixed plate 3 by a thread for fine adjustment. The thread and end face have a 2mm clearance groove, representing the maximum range of taper adjustment. The taper of the expansion shaft 1 and the taper of the expansion sleeve 4 are selected between 5-10 degrees to meet the requirements for precise adjustment of the outer diameter. The taper fit between the expansion shaft 1 and the expansion sleeve 4 should reach over 90%.

[0037] For the polishing sleeve 5, please refer to... Figure 5 As shown, the polishing sleeve 5 is made of nitrile rubber and is integrated with the expansion sleeve by brushing or molding. The rubber portion intruding into the groove of the expansion sleeve 4 should be retained, as it is the connecting part with the expansion sleeve 4. The rubber material and the expansion sleeve 4 are tightly bonded to adjust the elasticity of the expansion sleeve 4. When brushing or molding the polishing sleeve 5, a allowance should be left on the outer diameter of the polishing sleeve 5. The working surface dimensions of the polishing sleeve can be achieved by machining or grinding to the required dimensions.

[0038] The advantages of this application are:

[0039] 1. The adjustable precision internal hole polishing device can adjust the expansion and contraction amounts to achieve finishing of different hole diameters. Suitable for... Polishing of through holes or blind holes.

[0040] 2. The expansion and tightening of the flexible polishing sleeve of this device generates elastic deformation, which gently contacts the processing surface, effectively avoiding hard contact caused by rigid tools and scratches caused by uneven abrasive, ensuring uniform polishing amount, and meeting the high precision requirements of the inner hole of precision parts and the technical requirements of sealing of the mating parts.

[0041] 3. The surface roughness of the processed surface by this device reaches Ra0.05-Ra0.4. Combined with the heat treatment hardness of different materials and the surface treatment method of the inner hole, the roughness of the polished surface is reduced by 50-60% compared with that before polishing.

[0042] 4. This device has a reasonable structure and is flexible in operation.

[0043] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An adjustable precision internal hole polishing device, characterized in that: The device includes: an expansion shaft, an expansion sleeve, a polishing sleeve, an upper fixing plate, a lower fixing plate, and fixing screws; The expansion sleeve is cylindrical, with a tapered hole machined in the center, and is divided into N lobes along the circumference; a polished sleeve is provided on the outside of the expansion sleeve; The expansion shaft consists of a long shaft section, a tapered section, and a threaded section from top to bottom. The tapered section of the expansion shaft mates with the tapered hole of the expansion sleeve. The radial expansion or contraction of the expansion sleeve is controlled by the axial up-and-down movement of the expansion shaft relative to the expansion sleeve, thereby adjusting the radial dimension of the polishing sleeve. The upper end face of the expansion sleeve is provided with an upper fixed plate receiving hole, and the lower end face of the expansion sleeve is provided with a lower fixed plate receiving hole. Each segment of the expansion sleeve is provided with a through hole. The upper fixed plate is provided with N screw through holes, and the lower fixed plate is provided with N threaded holes. N screws pass through the upper fixed plate, the expansion sleeve and the lower fixed plate in sequence, thereby fixing the upper and lower fixed plates and the expansion sleeve. The lower fixed plate is provided with a threaded adjustment hole at its center. The threaded adjustment hole cooperates with the threaded section of the expansion shaft to control the radial dimension adjustment of the polishing sleeve.

2. The apparatus according to claim 1, characterized in that: A slot is provided between the end faces of the threaded section and the tapered section. The axial length of the slot and the axial length of the threaded section constitute the maximum range of axial movement adjustment of the expansion shaft relative to the expansion sleeve.

3. The apparatus according to claim 1, characterized in that: The cone angle of the tapered section of the expansion shaft is 10° to 15°.

4. The apparatus according to claim 1, characterized in that: The polishing sleeve is manufactured in the following manner: A cylindrical mold is placed concentrically outside the expansion sleeve. Rubber is injected between the mold and the expansion sleeve and vulcanized, so that the polishing sleeve and the expansion sleeve are integrated. After vulcanization, the rubber is shaped to adjust the working surface size of the polishing sleeve.

5. The apparatus according to claim 4, characterized in that: During the manufacturing of the polishing sleeve, the rubber that penetrates into the gaps between the N segments of the expansion sleeve is also reshaped, and the length of the polishing sleeve penetrating the gaps is adjusted, thereby adjusting the elasticity of the device.

6. The apparatus according to claim 1, characterized in that: The expansion sleeve is divided into segments by radial cutting grooves, and each radial cutting groove passes through the axis of the expansion sleeve.

7. The apparatus according to claim 6, characterized in that: The expansion sleeve is divided into N equal parts, where N ≥ 3.

8. The apparatus according to claim 6, characterized in that: The expansion sleeve is not divided into N unequal segments, where N≥4.

9. The apparatus according to claim 6, characterized in that: The diameter of the through hole in each segment of the expansion sleeve is 0.5mm to 0.8mm larger than the screw diameter.

10. The apparatus according to claim 6, characterized in that: The outer surface of the polishing sleeve is the working surface, where abrasive is coated or adhered to polish the surface to be polished.

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