A combined processing method for centerless belt grinding and polishing using multi-segment curved guide rollers

Abstract

This invention discloses a combined centerless belt grinding and polishing method using multi-segment curved guide rollers, applicable to the automated production of precision machining on the outer cylindrical surfaces of cylindrical workpieces such as bearing rollers. On one hand, it employs a parallel structure of three parallel guide rollers with different curved surfaces. The first section of the guide roller is a conjugate conical surface used to drive the workpiece for continuous axial feed; the second section is a cylindrical surface used for grinding and polishing; and the third section is a uniform conical surface used to drive the workpiece for receiving. On the other hand, it integrates belt grinding and polishing processes into a single centerless machining device. This patent can be used to obtain good surface quality, improve production efficiency, reduce equipment structural complexity, reduce external feeding auxiliary devices, simplify production space, and lower manufacturing costs.

Description

Technical Field

[0001] This invention relates to the field of equipment manufacturing technology, specifically a combined processing method for centerless belt grinding and polishing using multi-segment curved guide rollers. Background Technology

[0002] The traditional centerless machining process for bearing rollers is divided into two stages: centerless grinding and ultra-precision grinding, each using different processing equipment. The grinding wheels and oilstones used are rigid grinding tools, which easily cause large scratches and other surface defects on the workpiece surface. Automated production of traditional centerless grinding and ultra-precision grinding mainly relies on the angle between the guide rollers and the grinding wheel or between two guide rollers. This angle decomposes the contact force between the guide rollers and the workpiece into loading pressure and axial feed thrust. However, the presence of this angle prevents the workpiece from fully engaging with the guide rollers and causes complex dynamic problems, affecting the rotational stability of the cylindrical workpiece.

[0003] This case arose in order to resolve the aforementioned issues. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a combined processing method for centerless belt grinding and polishing using multi-segment curved guide rollers. On one hand, it integrates belt grinding and free abrasive polishing processes into a single centerless processing device. On the other hand, while maintaining the parallelism of the axes of the two guide rollers, it designs multi-segment guide rollers with conjugate conical surfaces. This not only enables continuous axial feeding of the cylindrical workpiece but also ensures full contact and fit between the cylindrical workpiece and the guide rollers in the processing area, which is beneficial for improving shape accuracy and solves the problems mentioned in the background technology.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: a multi-segment curved surface guide roller, comprising an independent front guide roller and a rear guide roller, wherein the rotation axes of the front guide roller and the rear guide roller are placed parallel to each other, and their geometric shapes are divided into three different structural segments along the axes:

[0008] S1. The first section serves as the feed section for the cylindrical workpiece. The outer circular surfaces of the front guide roller and the rear guide roller are a pair of conjugate conical surfaces. The generatrix of the outer circular surface of the front guide roller is inclined at an angle α to the outside of the cylindrical surface, and the generatrix of the outer circular surface of the rear guide roller is inclined at an angle α to the inside of the cylindrical surface. This causes the axis of the cylindrical workpiece supported by the guide roller in this section to be non-parallel to the axis of rotation of the guide roller. The cylindrical workpiece and the two guide rollers form an angle α in the horizontal plane and an angle β in the vertical plane. This creates a thrust of the guide rollers on the cylindrical workpiece in the axial direction of the cylindrical workpiece, causing the cylindrical workpiece to make axial feed motion.

[0009] S2. The second section serves as the polishing section for cylindrical workpieces. The outer curved surfaces of the front and rear guide rollers are both cylindrical surfaces with the same diameter. A loading device is provided above the two guide rollers for grinding and polishing the cylindrical workpieces.

[0010] S3. The third section serves as the discharge section for cylindrical workpieces. The outer circular surfaces of the front guide roller and the rear guide roller on opposite sides are the same conical surfaces, and the generatrices of their outer circular surfaces are inclined inwards towards the cylindrical surface at an angle γ.

[0011] As a preferred option, the feed angle α is relatively small, and can be set to 1° to 6°; ω 导辊 R 导辊 cosα≈ω 圆柱工件 R 圆柱工件 .

[0012] As a preferred embodiment, the discharge angle γ is further greater than the feed angle α, and can be set to 5° to 30°; ω 导辊 R 导辊 sinα≈v 圆柱工件 .

[0013] A combined machining method for centerless belt grinding and polishing using multi-segment curved guide rollers includes the following machining processes:

[0014] Step 1: Rotate the front and rear guide rollers at the same speed and in the same direction; place the cylindrical workpiece between the two guide rollers through the feeding device; under the contact force between the guide rollers and the cylindrical workpiece, the cylindrical workpiece makes axial feeding motion; when the previous cylindrical workpiece moves to the middle section of the guide roller, the guide roller no longer provides axial thrust to the cylindrical workpiece, but the axial motion of the subsequent cylindrical workpiece provides axial thrust to the previous cylindrical workpiece, so that the cylindrical workpiece continues to make axial motion.

[0015] Step two: The spatial position of the substrate is adjusted by the feed system so that both the abrasive belt and the polishing head can contact the cylindrical workpiece and achieve the specified contact force. Simultaneously, driven by the pulley drive device, the abrasive belt moves continuously, and free abrasive polishing slurry is sprayed into the contact area between the polishing head and the cylindrical workpiece. When the cylindrical workpiece passes the abrasive belt, the outermost abrasive layer of the abrasive belt removes material from the outer surface of the cylindrical workpiece, realizing bonded abrasive grinding. When the cylindrical workpiece passes the polishing head, the free abrasive contained in the polishing slurry removes material from the outer surface of the cylindrical workpiece, realizing free abrasive polishing.

[0016] Step 3: When the cylindrical workpiece moves along the curved surface of the guide roller to the top of the receiving device, the cylindrical workpiece falls to the receiving device due to its own gravity because the distance between the outer circular surfaces of the guide roller is greater than the diameter of the cylindrical workpiece. This completes the processing flow.

[0017] Step four: When the guide rollers have shape errors due to long-term use and wear, the feeding system is adjusted to make the sanding belt move along the specified spatial curve path. The sanding belt is used to remove a small amount of material from the outer surface of the two guide rollers at the same time, so as to correct the shape errors of the two guide rollers simultaneously.

[0018] A processing apparatus for a combined centerless belt grinding and polishing method using multi-segment curved guide rollers includes a feeding device, a receiving device, and a loading device. The feeding device is located above the front and rear guide rollers, and the receiving device is located below the rear guide rollers. The loading device includes a base plate located above the middle section of the guide rollers, and the base plate is parallel to the axis of the guide rollers. A pulley drive device is mounted on the base plate, and a drive wheel is connected to the output end of the pulley drive device. A driven wheel II is mounted directly below the drive wheel, and a driven wheel I is located between the driven wheel II and the drive wheel, forming a triangular relationship. A tensioning mechanism is mounted on the driven wheel I via a rotating shaft. The drive wheel, driven wheel I, and driven wheel II are all wrapped with a closed transmission abrasive belt. A polishing head clamp is also mounted at the bottom of the base plate, and a polishing head is fixed on the polishing head clamp. The base plate can achieve XYZ three-axis motion under the action of an external feeding system.

[0019] As a preferred option, the abrasive belt can be any one of the following two types: one type contains two layers of material, wherein the layer in contact with the pulley is a flat belt layer, which can be any one of polyurethane, polyester, rubber, or polyester canvas, and the layer in contact with the cylindrical workpiece is an abrasive layer, which can be any one of diamond film or sandpaper, and the abrasive layer and the flat belt layer are fixed with adhesive; the other type is a regular abrasive belt.

[0020] As a preferred embodiment, the sanding belt and polishing head are further positioned above the polishing sections of the front and rear guide rollers, with the lowest point of the sanding belt and the bottom surface of the polishing head at adjacent horizontal positions, wherein the sanding belt is located on the side closer to the feeding device and the polishing head is located on the side closer to the receiving device.

[0021] As a preferred embodiment, a polishing pad is further attached to the bottom of the polishing head, and flow channels are provided on the outer and inner sides of the polishing head to deliver the polishing slurry from the flow channels to the contact area between the polishing head and the workpiece.

[0022] (III) Beneficial Effects

[0023] After adopting the above technical solution, the present invention provides a combined processing method for centerless belt grinding and polishing using multi-segment curved guide rollers, which has the following advantages compared with the prior art:

[0024] (1) Compared with the problems of workpiece contact stability, complex dynamics, and complex structure caused by the non-parallelism of the guide rollers and grinding wheel axis or the non-parallelism of the double guide roller axes in traditional centerless grinding and ultra-precision machining equipment, the present invention realizes the axial feed motion, rotational motion, and material collection action of the cylindrical workpiece by means of the multi-segment curved surface of the guide rollers on the basis of parallel double guide roller axes. This can reduce the dynamic fluctuation of the cylindrical workpiece in the machining area and improve the shape accuracy and surface quality of the cylindrical workpiece. In addition, the present invention can reduce the external auxiliary devices for driving the cylindrical workpiece feed, and by optimizing the shape of the guide rollers, it can also reduce the complexity of the equipment structure and reduce manufacturing costs.

[0025] (2) Compared with the traditional centerless grinding and ultra-precision grinding processes which use different equipment, the present invention integrates centerless belt grinding and centerless polishing processes into one processing equipment, which can reduce the conveying links of workpieces between different equipment, simplify the production space, reduce manufacturing costs, and improve production efficiency.

[0026] (3) Compared with traditional centerless grinding using rigid grinding wheels, this invention proposes to use a flexible abrasive belt with a diamond film or other abrasive layer plus a flat belt layer for centerless grinding, so that the abrasive belt and the workpiece are in flexible contact, which helps to suppress the generation of surface defects such as large scratches, thus obtaining better workpiece surface quality. At the same time, the relative speed between the abrasive belt and the workpiece is very high, which can also obtain higher material removal efficiency. Attached Figure Description

[0027] Figure 1 This is a three-dimensional view of the overall layout of the present invention;

[0028] Figure 2 This is a side view of the overall layout of the present invention;

[0029] Figure 3 This is a front view of the overall layout of the present invention and a diagram showing the motion path of the cylindrical workpiece on the vertical plane;

[0030] Figure 4 This is a top view of the geometry of the two guide rollers of the present invention and a process diagram of the motion path of the cylindrical workpiece on the horizontal plane;

[0031] Figure 5 The roughness measurement results (Sa2 0.48 nm) of the outer cylindrical surface of the silicon nitride ceramic roller of the present invention after machining are shown in the figure.

[0032] Figure 6 The image shows the microscopic morphology of the outer cylindrical surface of the silicon nitride ceramic roller after machining (Sa 20.48nm).

[0033] In the figure, 1. substrate; 2. driving wheel; 3. driven wheel I; 4. driven wheel II; 5. sanding belt; 6. polishing head clamp; 7. polishing head; 8. tensioning mechanism; 9. front guide roller; 10. rear guide roller; 11. pulley drive device; 12. feeding device; 13. material receiving device; 14. cylindrical workpiece. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0035] See appendix Figure 1-4 As shown, a combined centerless belt grinding and polishing method using multi-segment curved guide rollers is used for the automated production of precision machining of the outer cylindrical surface of cylindrical workpieces 14 such as bearing rollers. It employs a front guide roller 9 and a rear guide roller 10, with their rotating shafts placed parallel to each other. Their geometry is divided into three different structural segments along the axis:

[0036] (1) In the section of the front guide roller 9 and the rear guide roller 10 near the feed device 12, the outer circular surfaces of the two guide rollers form a pair of conjugate conical surfaces. At the same time, the generatrix of the outer circular surface of the front guide roller 9 is inclined at an angle α to the outside of the cylindrical surface, and the generatrix of the outer circular surface of the rear guide roller 10 is inclined at an angle α to the inside of the cylindrical surface. This makes the axis of the cylindrical workpiece 14 supported by the guide roller in this section not parallel to the axis of rotation of the guide roller. The two form an angle α in the horizontal plane and an angle β in the vertical plane. This creates a thrust of the guide roller on the cylindrical workpiece 14 in the axial direction of the cylindrical workpiece 14, causing the cylindrical workpiece 14 to make axial feed motion.

[0037] (2) In the middle section between the front guide roller 9 and the rear guide roller 10, the outer curved surfaces of the two guide rollers are cylindrical surfaces with the same diameter. Above the two guide rollers, the sand belt 5 and the polishing head 7 are placed so that the lowest point of the sand belt 5 and the bottom surface of the polishing head 7 are at the same level. The sand belt 5 is located on the side closer to the feeding device 12, and the polishing head 7 is located on the side closer to the receiving device 13.

[0038] (3) In the section of the front guide roller 9 and the rear guide roller 10 near the receiving device 13, the outer circular curved surfaces of the two guide rollers are the same conical surfaces, and the generatrices of their outer circular curved surfaces are inclined at an angle γ towards the inner side of the cylindrical surface.

[0039] The processing steps are as follows:

[0040] Two guide rollers rotate in the same direction at the same speed. A cylindrical workpiece 14 is placed between the two guide rollers via a feeding device 12. Under the contact force between the guide rollers and the cylindrical workpiece 14, the cylindrical workpiece 14 performs an axial feed motion. When the preceding cylindrical workpiece 14 reaches the middle section of the guide rollers, the guide rollers no longer provide axial thrust to the cylindrical workpiece 14. Instead, the axial movement of the subsequent cylindrical workpiece 14 provides the axial thrust to the preceding cylindrical workpiece 14, allowing the cylindrical workpiece 14 to continue its axial movement. The spatial position of the substrate 1 is adjusted by the feeding system so that both the sanding belt 5 and the polishing head 7 can contact the cylindrical workpiece 14 and achieve the specified contact force. Simultaneously, driven by the pulley drive device 11... The abrasive belt 5 moves continuously, and free abrasive polishing liquid is sprayed into the contact area between the polishing head 7 and the cylindrical workpiece 14. When the cylindrical workpiece 14 passes the abrasive belt 5, the outermost abrasive layer of the abrasive belt 5 removes material from the outer surface of the cylindrical workpiece 14, realizing bonded abrasive grinding. When the cylindrical workpiece 14 passes the polishing head 7, the free abrasive contained in the polishing liquid removes material from the outer surface of the cylindrical workpiece 14, realizing free abrasive polishing. When the cylindrical workpiece 14 moves along the curved surface of the guide roller to above the receiving device 13, since the distance between the outer surfaces of the guide rollers is greater than the diameter of the cylindrical workpiece 14, the cylindrical workpiece 14 falls to the receiving device 13 due to its own gravity, completing the processing flow.

[0041] (5) When the guide rollers have shape errors due to long-term use and wear, the sand belt 5 can be adjusted to move along the specified spatial curve path by adjusting the feeding system. The sand belt 5 can be used to remove a small amount of material from the outer surface of the two guide rollers at the same time, thereby correcting the shape errors of the two guide rollers simultaneously.

[0042] See appendix Figure 1-2 As shown, the processing apparatus for implementing the aforementioned processing method includes a front guide roller 9, a rear guide roller 10, a feeding device 12, a take-up device 13, a pulley drive device 11, an abrasive belt 5, a polishing head clamp 6, a polishing head 7, and a substrate 1. The feeding device 12 is located above one end of the guide roller, while the take-up device 13 is located below the other end of the guide roller. The substrate 1 is positioned above the middle section of the guide roller, making the substrate 1 parallel to the axis of the guide roller. The pulley drive device 11 is mounted on the substrate 1, the driving wheel 2 is connected to the pulley drive device 11, the shaft of the driven wheel I3 is mounted on the tensioning mechanism 8, the tensioning mechanism 8 is fixed to the substrate 1, the shaft of the driven wheel II4 is fixed to the substrate 1, and the abrasive belt 5 is fitted around the outside of the driving wheel 2, driven wheel I3, and driven wheel II4. The polishing head clamp 6 is fixed to the substrate 1, and the polishing head 7 is fixed to the polishing head clamp 6. The substrate 1 can achieve XYZ three-axis motion under the action of the feeding system.

[0043] Two types of abrasive belts 5 can be selected. One type contains two layers of material, with the layer in contact with the pulley being a flat belt layer, which can be made of polyurethane, polyester, rubber, or polyester canvas, and the layer in contact with the cylindrical workpiece 14 being an abrasive layer, which can be made of diamond film or sandpaper. The abrasive layer and the flat belt layer are fixed together with adhesive. The other type is a regular abrasive belt 5.

[0044] A polishing pad is attached to the bottom of the polishing head 7. The polishing head 7 has flow channels on its outer and inner sides to deliver polishing liquid from the flow channels to the contact area between the polishing head 7 and the workpiece.

[0045] Specific application examples are as follows:

[0046] A silicon nitride ceramic cylindrical roller with a diameter of 20 mm and a length of 30 mm was selected as the workpiece. A 30 mm wide abrasive belt 5 was fabricated by bonding a 1 μm diamond film to the outer surface of a polyurethane flat belt using nano-adhesive, with the abrasive belt 5 having a linear speed of 30 mm / s. The guide roller had a cylindrical surface diameter of 80 mm, a generatrix inclination angle of 4° on the conjugate conical surface, and a double guide roller rotation speed of 2000 rpm. The height of the base plate 1 was adjusted so that the contact pressure between the driven roller II 4 and the workpiece was set to 40 N. Processing under the above conditions according to the processing method described in this patent can reduce the surface roughness of the outer diameter of the silicon nitride ceramic cylindrical roller to Sa 20.48 nm, significantly improving the surface quality. The surface roughness test results of the outer diameter of the silicon nitride ceramic cylindrical roller after processing are shown below. Figure 5 As shown in the figure, the microscopic observation results of the surface morphology are as follows: Figure 6 As shown.

[0047] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-segment curved surface guide roller, characterized in that: It includes independent front and rear guide rollers, whose rotation axes are placed parallel to each other, and whose geometry is divided into three different structural segments along the axis: S1. The first section serves as the feed section for the cylindrical workpiece. The outer circular surfaces of the front guide roller and the rear guide roller are a pair of conjugate conical surfaces. The generatrix of the outer circular surface of the front guide roller is inclined at an angle α to the outside of the cylindrical surface, and the generatrix of the outer circular surface of the rear guide roller is inclined at an angle α to the inside of the cylindrical surface. This causes the axis of the cylindrical workpiece supported by the guide roller in this section to be non-parallel to the axis of rotation of the guide roller. The cylindrical workpiece and the two guide rollers form an angle α in the horizontal plane and an angle β in the vertical plane. This creates a thrust of the guide rollers on the cylindrical workpiece in the axial direction of the cylindrical workpiece, causing the cylindrical workpiece to make axial feed motion. S2. The second section serves as the polishing section for cylindrical workpieces. The outer curved surfaces of the front and rear guide rollers are both cylindrical surfaces with the same diameter. A loading device is provided above the two guide rollers for grinding and polishing the cylindrical workpieces. S3. The third section serves as the discharge section for cylindrical workpieces. The outer circular surfaces of the front guide roller and the rear guide roller on opposite sides are the same conical surfaces, and the generatrices of their outer circular surfaces are inclined inwards towards the cylindrical surface at an angle γ.

2. The multi-segment curved surface guide roller according to claim 1, characterized in that: The tilt angle α for feeding cylindrical workpieces is set to 1° to 6°, ω 前 / 后导辊 R 前 / 后导辊 cosα≈ω 圆柱工件 R 圆柱工件 The tilt angle γ on the discharge side is greater than the feed angle α, and is set to 5° to 30°; ω 前 / 后导辊 R 前 / 后导辊 sinα≈v 圆柱工件 ω 前导辊 =ω 后导辊 .

3. A method for combined grinding and polishing of a centerless belt abrasive using a multi-segment curved surface guide roller, wherein the multi-segment curved surface guide roller described in claim 1 is characterized in that: The following processing steps are included: Step 1: Rotate the front and rear guide rollers at the same speed and in the same direction; place the cylindrical workpiece between the two guide rollers through the feeding device; under the contact force between the guide rollers and the cylindrical workpiece, the cylindrical workpiece makes axial feeding motion; when the previous cylindrical workpiece moves to the middle section of the guide roller, the guide roller no longer provides axial thrust to the cylindrical workpiece, but the axial motion of the subsequent cylindrical workpiece provides axial thrust to the previous cylindrical workpiece, so that the cylindrical workpiece continues to make axial motion. Step two: The spatial position of the substrate is adjusted by the feed system so that both the abrasive belt and the polishing head can contact the cylindrical workpiece and achieve the specified contact force. Simultaneously, driven by the pulley drive device, the abrasive belt moves continuously, and free abrasive polishing slurry is sprayed into the contact area between the polishing head and the cylindrical workpiece. When the cylindrical workpiece passes the abrasive belt, the outermost abrasive layer of the abrasive belt removes material from the outer surface of the cylindrical workpiece, realizing bonded abrasive grinding. When the cylindrical workpiece passes the polishing head, the free abrasive contained in the polishing slurry removes material from the outer surface of the cylindrical workpiece, realizing free abrasive polishing. Step 3: When the cylindrical workpiece moves along the curved surface of the guide roller to the top of the receiving device, the cylindrical workpiece falls to the receiving device due to its own gravity because the distance between the outer circular surfaces of the guide roller is greater than the diameter of the cylindrical workpiece. This completes the processing flow. Step four: When the guide rollers have shape errors due to long-term use and wear, the feeding system is adjusted to make the sanding belt move along the specified spatial curve path. The sanding belt is used to remove a small amount of material from the outer surface of the two guide rollers at the same time, so as to correct the shape errors of the two guide rollers simultaneously.

4. The processing apparatus for a combined centerless belt grinding and polishing method using multi-segment curved guide rollers according to claim 3, characterized in that: The system includes a feeding device, a receiving device, and a loading device. The feeding device is located above the front and rear guide rollers, and the receiving device is located below the rear and rear guide rollers. The loading device includes a base plate located above the middle section of the guide rollers, and the base plate is parallel to the axis of the guide rollers. A pulley drive device is mounted on the base plate, and the output end of the pulley drive device is connected to a drive wheel. A driven wheel II is mounted directly below the drive wheel, and a driven wheel I is located between the driven wheel II and the drive wheel, forming a triangular relationship. A tensioning mechanism is mounted on the driven wheel I via a rotating shaft. The drive wheel, driven wheel I, and driven wheel II are all wrapped with a closed transmission sanding belt. A polishing head clamp is also mounted at the bottom of the base plate, and a polishing head is fixed on the polishing head clamp. The base plate can achieve XYZ three-axis motion under the action of an external feeding system.

5. The processing apparatus for a combined centerless belt grinding and polishing method using multi-segment curved guide rollers according to claim 4, characterized in that: The abrasive belt can be any one of the following two types: one type contains two layers of material, wherein the layer in contact with the pulley is a flat belt layer, which can be any one of polyurethane, polyester, rubber, or polyester canvas, and the layer in contact with the cylindrical workpiece is an abrasive layer, which can be any one of diamond film or sandpaper, and the abrasive layer and the flat belt layer are fixed with adhesive; the other type is an ordinary abrasive belt.

6. The processing apparatus for a combined centerless belt grinding and polishing method using multi-segment curved guide rollers according to claim 4, characterized in that: The sanding belt and polishing head are located above the polishing sections of the front and rear guide rollers, and the lowest point of the sanding belt and the bottom surface of the polishing head are at the same horizontal position adjacent to each other. The sanding belt is located on the side closer to the feeding device, and the polishing head is located on the side closer to the receiving device.

7. The processing apparatus for a combined centerless belt grinding and polishing method using multi-segment curved guide rollers according to claim 4, characterized in that: A polishing pad is attached to the bottom of the polishing head, and flow channels are provided on the outer and inner sides of the polishing head to transport the polishing liquid from the flow channels to the contact area between the polishing head and the workpiece.

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