High-precision constant-force grinding equipment and constant-force grinding method

Abstract

The invention provides high-precision constant-force grinding equipment and a constant-force grinding method. The grinding equipment comprises an abrasive belt, a grinding wheel and a grinding wheel, the grinding wheel is rotationally arranged on the supporting shaft, the two ends, in the Y direction, of the supporting shaft are fixed to the grinding head support, and the grinding head support extends in the X direction; a first X-direction linear displacement unit is arranged on the grinding head support. The adjusting frame is located in the area defined by the grinding head support and located outside the grinding wheel. The adjusting frame is slidably connected with the grinding head support in the X direction, one end of the adjusting frame makes contact with the first X-direction linear displacement unit, the other end of the adjusting frame is a groove, adjusting holes are formed in the two side walls, distributed in the Y direction, of the groove, top wheels and connecting pieces are sequentially embedded in the adjusting holes from inside to outside, and supporting shafts penetrate through the top wheels. An adjusting gap is formed between the top wheel and the supporting shaft; before the polishing procedure, the outer edge of the top wheel is higher than the polishing surface of the abrasive belt attached to the grinding wheel; and a second X-direction linear displacement unit. The high-precision constant-force grinding device can realize high-precision constant-force grinding.

Description

Technical Field

[0001] The present invention belongs to the technical field of belt sanders, and particularly relates to a high-precision constant-force grinding device and a constant-force grinding method. Background Art

[0002] In recent years, with the development of technology, the replacement of manual labor by machines has gradually become a trend. In the process of machining precision parts, it is often necessary to grind or polish the surface of the workpiece. Belt sanders are often used in the polishing process, and belt sanders have become the choice for many automated grinding projects. In practical applications, the grinding removal amount is generally ensured by the relative position accuracy between the workpiece and the contact wheel. However, the robot has low rigidity and limited positioning accuracy, resulting in low precision in grinding and polishing. In order to improve the grinding precision, it is necessary to ensure a constant force during grinding for the object to be ground. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-precision constant-force grinding device and a constant-force grinding method, which can achieve constant-force grinding and precise control of the feed rate. The technical solutions adopted are as follows: A high-precision constant-force grinding device includes: A sand belt 5, which is of a closed structure, and its driving surface is in contact with a tension wheel 15, a driving wheel 16, and a grinding wheel 4; the driving wheel 16 is rotatably arranged on a frame 1, and the tension wheel 15 is arranged on the frame 1; The grinding wheel 4 is rotatably arranged on a support shaft 3. Both ends of the support shaft 3 in the Y direction are fixed to a grinding head bracket 2. The grinding head bracket 2 extends in the X direction. One end of it is connected to the frame 1 through a connecting frame 9, and the other end is open to place an adjusting frame 6; a first X-direction linear displacement unit is provided on the grinding head bracket 2; The adjusting frame 6 is located within the area surrounded by the grinding head bracket 2 and outside the grinding wheel 4; The adjusting frame 6 is slidably connected to the grinding head bracket 2 in the X direction. One end of it is in contact with the first X-direction linear displacement unit, and the other end is a groove. Adjusting holes are opened on both side walls of the groove distributed in the Y direction. A top wheel 7 and a connecting piece 8 are sequentially embedded in the adjusting holes from the inside to the outside, and the support shaft 3 passes through the top wheel 7; An adjusting gap is formed between the top wheel 7 and the support shaft 3; the top wheel 7 extends out of the grinding head bracket 2 in the Y direction and forms a preset gap with the grinding wheel 4; before the grinding process, the outer edge of the top wheel 7 is higher than the grinding surface of the sand belt in contact with the grinding wheel 4; And a second X-direction linear displacement unit is arranged on a base, and its output end is connected to the frame 1, and the frame 1 is slidably connected to the base in the X direction.

[0004] Preferably, the grinding head bracket 2 includes: A pair of frame bodies, extending along the X direction and arranged oppositely, are connected by a transition frame 17, and one of the frame bodies is connected to the machine frame 1; For the first X-direction linear displacement unit, its housing is connected to the transition frame 17, and its output end passes through the transition frame 17.

[0005] Preferably, the adjusting frame 6 includes: A U-shaped frame; An adjusting block 11, connected to the U-shaped frame, and connected to a slide rail on one of the frame bodies.

[0006] Preferably, the connecting member 8 has a hollow structure, its outer edge is embedded in the adjusting hole of the adjusting frame 6, and its inner edge is in contact with the outer edge of the top wheel 7.

[0007] Preferably, a limiting ring is formed at one end of the connecting member 8 away from the grinding wheel 4, and the limiting ring covers the adjusting hole and is in contact with the grinding head support 2.

[0008] Preferably, the top wheel 7 includes a first cylinder, a second cylinder and a third cylinder which are connected in sequence and have gradually increasing outer diameters; The first cylinder is embedded in the connecting member 8 and is flush with it; Both the second cylinder and the third cylinder extend out of the adjusting frame 6.

[0009] Preferably, the first X-direction linear displacement unit is an electric cylinder 10; the second X-direction linear displacement unit is a constant-force cylinder 13.

[0010] Preferably, the axle of the tensioning wheel 15 is arranged on the tensioning block, the tensioning block is sleeved on the guiding column on the machine frame 1, and the tensioning block is hinged to the output end of the tensioning cylinder 14.

[0011] Preferably, a bearing is arranged between the support shaft 3 and the grinding wheel 4, and a limiting member is arranged between the bearing and the grinding wheel 4.

[0012] A constant-force grinding method includes the following steps: Step 1, adjust the feed rate; Start the first X-direction linear displacement unit to drive the top wheel 7 to feed along the X direction; when the top wheel 7 contacts the workpiece to be ground, the first X-direction linear displacement unit stops, and at this time, the top wheel 7 is adjusted so that its outer edge is lower than the grinding surface of the abrasive belt in contact with the grinding wheel 4; When the top wheel (7) contacts the workpiece to be ground, if the force applied by the top wheel (7) to the workpiece to be ground at this time > the grinding force F, continue to introduce gas into the rod chamber of the constant-force cylinder (13) until the pulling force applied by the constant-force cylinder (13) to the machine frame (1) is equal to the grinding force F; The top wheel (7) and the grinding surface are always in contact with the workpiece to be ground; Step 2: Perform the grinding process. When the workpiece to be ground is separated from the grinding surface, one grinding process ends; Step 3: Return the top wheel 7 to its original position; Step 4: Reduce the feed rate and repeat Steps 1 - 3 to achieve high-precision grinding.

[0013] Compared with the prior art, the advantages of the present invention are as follows: 1. Achieve constant-force grinding.

[0014] 2. The feed rate can be precisely controlled. Description of the Drawings

[0015] Figure 1 is a perspective view of the high-precision constant-force grinding equipment; Figure 2 is Figure 1 a partial view of; Figure 3 is a structural diagram of the grinding head support and the adjustment frame; Figure 4 is a schematic diagram of the position of the top wheel; Figure 5 is a connection schematic diagram between the connecting frame and the grinding head; Figure 6 is a schematic diagram of the installation method of the grinding head support; Figure 7 is a relative position schematic diagram of the top wheel, the connecting piece, the support shaft and the adjustment frame; Figure 8 is a relative position schematic diagram between the connecting piece and the top wheel; Figure 9 is a schematic diagram of the position of the preset gap; Figure 10 is a position relationship diagram between the top wheel and the grinding surface before the grinding process; Figure 11 is a schematic diagram of the installation position of the constant-force cylinder; Figure 12 is a schematic diagram of the installation position of the tensioning cylinder; Figure 13 is a connection relationship diagram between the support shaft and the grinding wheel; Figure 14 is a perspective view of the grinding wheel; Figure 15 is a perspective view of the support shaft.

[0016] Among them, 1 - frame, 2 - grinding head support, 3 - support shaft, 4 - grinding wheel, 5 - abrasive belt, 6 - adjustment frame, 7 - top wheel, 8 - connecting piece, 9 - connecting frame, 10 - electric cylinder, 11 - adjustment block, 12 - control power supply wire; 13 - constant-force cylinder, 14 - tensioning cylinder, 15 - Tension pulley, 16 - Driving pulley, 17 - Transition frame, 18 - Electro - hydraulic proportional valve. Detailed implementation mode

[0017] The high - precision constant - force grinding equipment and the constant - force grinding method of the present invention will be described in more detail below with reference to the schematic diagrams, in which the preferred embodiments of the present invention are shown. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as a broad guidance for those skilled in the art and not as a limitation to the present invention.

[0018] As Figures 1 - 15 , a high - precision constant - force grinding equipment, comprising: The abrasive belt 5, which is a closed structure, and its driving surface is in contact with the tension pulley 15, the driving pulley 16 and the grinding wheel 4; the driving pulley 16 is rotatably arranged on the frame 1, and the tension pulley 15 is fixed on the frame 1.

[0019] The abrasive belt 5 is a diamond abrasive belt.

[0020] The grinding wheel 4 is rotatably arranged on the support shaft 3, and both ends of the support shaft 3 in the Y - direction are fixed to the grinding head bracket 2; in this embodiment, the support shaft 3 is in interference fit with the holes on the grinding head bracket 2.

[0021] The grinding head bracket 2 extends in the X - direction, one end of which is connected to the frame 1 through the connecting frame 9, and the other end is open to place the adjusting frame 6, as Figures 3 - 6 shown.

[0022] A first X - direction linear displacement unit is provided on the grinding head bracket 2.

[0023] As Figure 5 shown, the grinding head bracket 2 includes: A pair of frame bodies, extending in the X - direction and arranged oppositely, connected by the transition frame 17 therebetween, and one of the frame bodies is connected to the frame 1; The first X - direction linear displacement unit, whose housing is connected to the transition frame 17, and its output end passes through the transition frame 17.

[0024] The adjusting frame 6 is located within the area surrounded by the grinding head bracket 2 and outside the grinding wheel 4, as Figure 3 shown. Wherein Figure 3 only a part of the adjusting frame 6 is shown.

[0025] The adjusting frame 6 is slidably connected to the grinding head bracket 2 in the X - direction, one end of which is in contact with the first X - direction linear displacement unit, and the other end is a groove. Adjusting holes are provided on both side walls of the groove distributed in the Y - direction, and a top wheel 7 and a connecting piece 8 are sequentially embedded in the adjusting holes from the inside to the outside, as Figure 7 shown.

[0026] AsFigure 3 As shown, the adjusting frame 6 includes: A U-shaped frame, which includes a support and a pair of adjusting plates connected to the support by fasteners.

[0027] An adjusting block 11, connected to the U-shaped frame, which is connected to a slide rail on a frame body.

[0028] The support shaft 3 passes through the top wheel 7.

[0029] An adjusting gap is formed between the top wheel 7 and the support shaft 3 along the radial direction, that is, the inner diameter of the small end of the top wheel 7 is greater than the outer diameter of the support shaft 3.

[0030] The top wheel 7 extends out of the grinding head support 2 along the Y direction and forms a preset gap with the grinding wheel 4, as Figure 9 shown.

[0031] Before the grinding process starts, the outer edge of the top wheel 7 is higher than the grinding surface of the abrasive belt in contact with the grinding wheel 4, as Figure 10 shown; Figure 10 In, "the outer edge of the top wheel 7 is higher than the grinding surface of the abrasive belt in contact with the grinding wheel 4", the reference object is the workpiece to be ground, that is, the grinding surface contacts the workpiece to be ground, and the top wheel 7 is used to control the grinding amount (feed amount).

[0032] As Figure 8 shown, the top wheel 7 includes a first cylinder, a second cylinder, and a third cylinder that are sequentially connected and have sequentially increasing outer diameters; The first cylinder is embedded in the connecting member 8 and is flush with it; Both the second cylinder and the third cylinder extend out of the adjusting frame 6, as Figure 9 shown.

[0033] And a second X-direction linear displacement unit, arranged on the base, whose output end is hinged to the frame 1, and the frame 1 is slidably connected to the base along the X direction, as Figure 11 shown.

[0034] Among them, the slide rail model: igus WS_20_80_200; Slider model: igus WJ200UM_01_20_ES_FG (a total of 4) As Figures 7 - 8 , the connecting member 8, which is a hollow structure, whose outer edge is embedded in the adjusting hole of the adjusting frame 6, and whose inner edge is embedded and fitted with the outer edge of the top wheel 7. Specifically, the connecting member 8 is a bearing.

[0035] One end of the connecting member 8 away from the grinding wheel 4 forms a limiting ring, and the limiting ring covers the adjusting hole and fits with the grinding head support 2.

[0036] In this embodiment, the first X-direction linear displacement unit is the electric cylinder 10. The model of the electric cylinder 10 is: IAI RCP6-RA4R-WA-35P-2.5-50-P3-M-B-MR.

[0037] The joint of the electric cylinder 10 is connected to the control unit through the control power supply line 12. The electric cylinder 10 is connected to the protection housing, and the joint passes through the protection housing.

[0038] The electric cylinder 10 is only used to control the position of the grinding wheel to ensure that it is always 0.2 - 1.0 mm higher than the surface of the abrasive belt to avoid interference; the electric cylinder 10 does not participate in the tensioning or pressure adjustment of the abrasive belt.

[0039] The second X-direction linear displacement unit is the constant-force cylinder 13.

[0040] As Figure 12 shown, the axle of the tensioning wheel 15 is arranged on the tensioning block. The tensioning block is sleeved on the guide post on the frame 1, and the tensioning block is hinged to the output end of the tensioning cylinder 14.

[0041] The driving wheel 16 is connected to the output shaft of the motor. The surface of the driving wheel is coated to reduce the slipping of the abrasive belt.

[0042] The model of the motor: Jie brand JDN90S2-2HP-NEMA-145TC (rotation speed 3450 rpm); The diameter of the driving wheel 16: 158.75 mm, the linear speed of the abrasive belt 58 m / s; The tensioning block is supported by the tensioning cylinder 14 to adjust the tension of the abrasive belt.

[0043] As Figures 13 - 15 shown, a bearing is arranged between the support shaft 3 and the grinding wheel 4, and a limiting member is arranged between the bearing and the grinding wheel 4.

[0044] During the grinding process of the prior art, as the grinding time prolongs, the pressure between the grinding surface and the workpiece to be ground will gradually decrease, and the magnitude of the contact pressure will cause different grinding roughness.

[0045] To make the roughness consistent, that is, to keep the contact pressure constant, the constant-force cylinder 13 is set.

[0046] As Figure 11 shown, an air inlet is arranged on the rodless cavity of the constant-force cylinder 13, an air outlet is arranged on its rodless cavity, a valve is arranged on the air outlet, the air inlet is sequentially connected to the air inlet pipe and the air source, and an electro-pneumatic proportional valve 18 is arranged on the air inlet pipe.

[0047] In this embodiment, the model of the electro-pneumatic proportional valve: SMC ITV1030-SEN-N2-DUQ00833 (pressure 0.05 - 0.7 MPa, accuracy ±0.5%); The electric proportional valve 18 is rectangular in shape and is connected to the intake pipe of the constant-force cylinder 13.

[0048] Model of the constant-force cylinder 13: SMC MQMLD16-30D (thrust 160 N); When surface roughness fluctuations are detected, the pressure adjustment step of the electric proportional valve 18 is 0.02 MPa, and the response time ≤ 50 ms.

[0049] Constant-force mode: The control unit sets the target pressure → the cylinder outputs a constant pulling force → the slide rail suppresses vibration; The working principle of this high-precision constant-force grinding equipment: Step 1: Adjust the feed rate and apply a grinding force F.

[0050] Start the electric cylinder 10. The electric cylinder 10 pushes the adjusting block 11 to move along the X direction, thereby driving the U-shaped frame to move along the X direction. That is, start the motor, and finally drive the top wheel 7 to feed along the X direction.

[0051] Since the support shaft 3 is fixed, an adjustment gap is formed between the support shaft 3 and the top wheel 7. Therefore, the top wheel 7 feeds and moves relative to the support shaft 3.

[0052] When the top wheel 7 contacts the workpiece to be ground, the electric cylinder 10 stops. At this time, the outer edge of the top wheel 7 is adjusted to be lower than the grinding surface of the abrasive belt that fits the grinding wheel 4.

[0053] That is, at this time, the top wheel 7 contacts the normal area of the workpiece to be ground, and the grinding surface contacts the raised area of the workpiece to be ground.

[0054] Before adjusting the feed rate, that is, before the grinding surface contacts the workpiece to be ground, the rod chamber is filled with gas. The piston rod of the constant-force cylinder 13 retracts into the rod chamber, and its acting force on the frame 1 is a pulling force F0. F0 < F.

[0055] After the grinding surface contacts the workpiece to be ground, if the force applied by the top wheel 7 (frame 1) to the workpiece to be ground > the grinding force F at this time, the output end of the constant-force cylinder 13 has a tendency to move backward; At this time, the electric proportional valve acts to increase the gas volume in the rod chamber, thereby increasing the pulling force of the constant-force cylinder 13 on the frame 1. When the pulling force applied by the constant-force cylinder 13 to the frame 1 is equal to the grinding force F set by the control unit, the electric proportional valve closes.

[0056] The output end of the constant-force cylinder 13 has a tendency to move backward, that is, the piston rod of the constant-force cylinder 13 has a tendency to extend from the rod chamber.

[0057] Specifically: The control unit sends an electrical signal to adjust the electric proportional valve in real time to increase the gas volume in the rod chamber of the constant-force cylinder 13, so that the pulling force applied by the constant-force cylinder 13 to the frame 1 is F.

[0058] Since there are only two acting forces on the frame 1, namely the pulling force exerted by the constant-force cylinder 13 and the reaction force of the workpiece to be polished.

[0059] Therefore, when the pulling force exerted by the constant-force cylinder 13 on the frame 1 is F, the polishing force exerted by the top wheel 7 (frame 1) on the workpiece to be polished is F.

[0060] During the above process, the top wheel 7 and the polishing surface are always in contact with the workpiece to be polished.

[0061] After the polishing surface comes into contact with the workpiece to be polished, if the force exerted by the top wheel 7 on the workpiece to be polished < F0 at this time, the output end of the constant-force cylinder 13 does not move.

[0062] Step 2: Perform the polishing process. When the workpiece to be polished is separated from the polishing surface, one polishing process ends.

[0063] Step 3: Return the top wheel 7 to its original position; Step 4: Reduce the feed rate and repeat steps 1 to 3 to achieve high-precision polishing.

[0064] As described above, since relative movement in the X direction can occur between the top wheel 7 and the grinding wheel 4, only by sequentially reducing the feed rate of the top wheel 7 in the X direction and performing the polishing process multiple times can high-precision polishing be achieved.

[0065] Since the adjusting block 11 and the slide rail are high-precision components, the polishing precision is further improved.

[0066] The above is only the preferred embodiment of the present invention and does not impose any limitation on the present invention. Any person skilled in the art within the technical field, without departing from the technical solution of the present invention, makes any form of equivalent replacement or modification and other changes to the technical solution and technical content disclosed by the present invention, all of which fall within the content of the technical solution of the present invention and still belong to the protection scope of the present invention.

Claims

1. A high-precision constant-force grinding device, characterized in that, Comprising: A sanding belt (5), which is of a closed structure, and its driving surface is in contact with a tensioning wheel (15), a driving wheel (16) and a grinding wheel (4); the driving wheel (16) is rotatably arranged on a frame (1), and the tensioning wheel (15) is arranged on the frame (1); The grinding wheel (4) is rotatably arranged on a support shaft (3), both ends of the support shaft (3) in the Y direction are fixed to a grinding head support (2), the grinding head support (2) extends in the X direction, one end thereof is connected to the frame (1) through a connecting frame (9), and the other end is open to place an adjusting frame (6); a first X-direction linear displacement unit is provided on the grinding head support (2); The adjusting frame (6) is located within the area surrounded by the grinding head support (2) and outside the grinding wheel (4); The adjusting frame (6) is slidably connected to the grinding head support (2) in the X direction, one end thereof is in contact with the first X-direction linear displacement unit, the other end is a groove, adjusting holes are opened on both side walls of the groove distributed in the Y direction, a top wheel (7) and a connecting piece (8) are sequentially embedded in the adjusting holes from the inside to the outside, and the support shaft (3) passes through the top wheel (7); An adjusting gap is formed between the top wheel (7) and the support shaft (3); the top wheel (7) extends out of the grinding head support (2) in the Y direction and forms a preset gap with the grinding wheel (4); before the grinding process, the outer edge of the top wheel (7) is higher than the grinding surface of the sanding belt in contact with the grinding wheel (4); And a second X-direction linear displacement unit is arranged on a base, and its output end is connected to the frame (1), and the frame (1) is slidably connected to the base in the X direction.

2. The high-precision constant-force grinding device according to claim 1, wherein The grinding head support (2) includes: A pair of frame bodies extending in the X direction and arranged oppositely, which are connected by a transition frame (17), and one of the frame bodies is connected to the frame (1); The first X-direction linear displacement unit, its housing is connected to the transition frame (17), and its output end passes through the transition frame (17).

3. The high-precision constant-force grinding device according to claim 2, characterized in that The adjusting frame (6) includes: A U-shaped frame; An adjusting block (11) connected to the U-shaped frame and connected to a slide rail on one of the frame bodies.

4. The high-precision constant-force grinding device according to claim 1, characterized in that, The connecting piece (8) is of a hollow structure, its outer edge is embedded in the adjusting hole of the adjusting frame (6), and its inner edge is in contact with the outer edge of the top wheel (7).

5. The high-precision constant-force grinding device according to claim 4, wherein One end of the connecting piece (8) away from the grinding wheel (4) forms a limiting ring, and the limiting ring covers the adjusting hole and is in contact with the grinding head support (2).

6. The high-precision constant-force grinding device according to claim 1, characterized in that The top wheel (7) includes a first cylinder, a second cylinder and a third cylinder that are sequentially connected and have sequentially increasing outer diameters; The first cylinder is embedded in the connecting piece (8) and is flush with it; The second cylinder and the third cylinder both extend out of the adjusting frame (6).

7. The high-precision constant-force grinding device according to claim 1, characterized in that The first X-direction linear displacement unit is an electric cylinder (10); the second X-direction linear displacement unit is a constant-force cylinder (13).

8. The high-precision constant-force grinding device according to claim 1, characterized in that The wheel shaft of the tensioning wheel (15) is arranged on a tensioning block, the tensioning block is sleeved on a guide post on the frame (1), and the tensioning block is hinged to the output end of a tensioning cylinder (14).

9. The high-precision constant-force grinding device according to claim 1, characterized in that A bearing is arranged between the support shaft (3) and the grinding wheel (4), and a limiting member is arranged between the bearing and the grinding wheel (4).

10. A constant force grinding method, characterized in that, Including the following steps: Step 1, adjusting the feed rate; Start the first X-direction linear displacement unit to drive the top wheel (7) to feed in the X direction; when the top wheel 7 touches the workpiece to be polished, the first X-direction linear displacement unit stops, and at this time, the top wheel (7) is adjusted so that its outer edge is lower than the polishing surface of the abrasive belt in contact with the grinding wheel (4); When the top wheel (7) touches the workpiece to be polished, if the force applied by the top wheel (7) to the workpiece to be polished at this time > the polishing force F, continue to introduce gas into the rod chamber of the constant force cylinder (13) until the pulling force applied by the constant force cylinder (13) to the frame (1) is equal to the polishing force F; The top wheel (7) and the polishing surface are always in contact with the workpiece to be polished; Step 2: Perform the polishing process. When the workpiece to be polished is separated from the polishing surface, one polishing process ends; Step 3: Return the top wheel (7) to its original position; Step 4: Reduce the feed rate and repeat steps 1 to 3 to achieve high-precision polishing.

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