Constant tangent angle grinding control system of centerless grinding machine

Abstract

The invention relates to the technical field of centerless grinding machines, in particular to a centerless grinding machine constant tangent angle grinding control system which comprises a constant tangent angle control module and a bracket lifting mechanism, the constant tangent angle control module calculates the theoretical center height h0 of a workpiece, then the workpiece is subjected to trial grinding, the grinding wheel linear speed and the guide wheel linear speed are kept constant, and the bracket lifting mechanism is started; the bracket lifting mechanism adjusts the center height h of the workpiece according to the shape of the workpiece to finely adjust the tangent angle R until a qualified product is ground and an accurate value of the tangent angle R is obtained, and after the tangent angle R is determined, the current center height value is obtained according to a formula (1); and subsequently grinding the workpiece according to grinding wheel linear speed constant control, guide wheel linear speed constant control and tangent angle constant control to obtain a qualified product.

Description

A constant tangential angle grinding control system for centerless grinders Technical Field

[0001] This invention relates to the field of centerless grinding technology, specifically to a constant tangent angle grinding control system for a centerless grinding machine. Background Technology

[0002] The grinding process of a centerless grinder involves continuous grinding, grain removal, and dressing by the grinding wheel and guide wheel. As shown in Figure 1, the diameters of the grinding wheel and guide wheel change continuously as they are dressed. With the support height remaining constant (i.e., the workpiece center height h remains constant), the tangent angle R at the contact point between the workpiece and the grinding wheel / guide wheel will continuously change. If the tangent angle is too large, the ground part will have a rounded (polygonal) shape. If the tangent angle is too small, ellipticity errors and workpiece runout in the grinding zone will occur. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a constant tangent angle grinding control system for a centerless grinder, which can maintain a constant tangent angle throughout the grinding process and improve the grinding quality of the product.

[0004] The technical solution is as follows: a constant tangent angle grinding control system for a centerless grinder, characterized in that it includes a constant tangent angle control module and a support lifting mechanism, wherein the constant tangent angle control module calculates the theoretical center height h0 of the workpiece. Where R0 is the theoretical value of the tangent angle at the contact point between the workpiece and the grinding wheel / guide wheel, and D... RW D is the diameter of the guide wheel. GW D is the diameter of the grinding wheel. WK The workpiece diameter is set; then, the workpiece is test-ground, with the grinding wheel and guide wheel linear speeds kept constant. The support lifting mechanism adjusts the workpiece center height h according to the workpiece shape to fine-tune the tangent angle R until a qualified product is produced, thus obtaining the precise value of the tangent angle R. After determining the tangent angle R, the current center height value is obtained according to formula (1). Subsequently, the workpiece is ground to obtain a qualified product by constant control of the grinding wheel linear speed, constant control of the guide wheel linear speed and constant control of the tangent angle.

[0005] A further feature is that the bracket lifting mechanism includes a bracket body and a worktable base. A worktable support plate is provided between the bracket body and the worktable base. The bottom of the bracket body and the top of the worktable support plate are in a horizontal sliding fit, while the bottom of the worktable support plate and the top of the worktable base are in a wedge fit. The bottom of the worktable support plate is connected to an inclined ball screw via a screw nut. The ball screw is connected to a servo motor mounted on the worktable base. A vertical guide mechanism is provided between the bracket body and the worktable base. The servo motor drives the ball screw, allowing the worktable support plate to change height along the wedge guide rail. The vertical guide mechanism restricts the movement of the bracket body in the height direction, and the center height of the workpiece on the bracket can be freely adjusted. The bottom of the worktable support plate and the worktable... The base has a dovetail-shaped wedge guide rail at its bottom, and a harmonic reducer is installed between the ball screw and the output shaft of the servo motor. A motor housing is installed around the servo motor. The servo motor is connected to the worktable base via a motor mount. An accordion-style protective cover is installed between the upper end of the motor mount and the worktable support plate. Rubber water-blocking sheets are installed around the bracket body. The vertical guide mechanism includes a vertical guide rod fixed to the worktable base and a guide block fixed to the bracket body. The vertical guide rod passes through the guide block and is slidably engaged. A position sensor transmitting module and a position sensor receiving module are engaged between the bracket body and the worktable base. The bracket body includes a guide wheel seat, with its front and rear ends respectively mounted on a front support and a rear support. The front and rear supports are connected to a support plate, and a guide plate is installed on the support plate.

[0006] After adopting this invention, a trial grinding is first performed to obtain the required tangent angle. Then, a three-constant control method is selected: constant control of grinding wheel linear speed, constant control of guide wheel linear speed, and constant control of tangent angle. The bracket lifting mechanism automatically adjusts the center height of the workpiece so that the tangent angle of the contact point between the workpiece and the grinding wheel and guide wheel remains constant, thereby improving the grinding quality of the workpiece. Attached Figure Description

[0007] Figure 1 is a schematic diagram of the workpiece grinding state; Figure 2 is the control interface of the control system of the present invention; Figure 3 is a schematic diagram of the bracket lifting mechanism; Figure 4 is a longitudinal sectional view of the bracket lifting mechanism. Detailed Implementation

[0008] A constant tangent angle grinding control system for a centerless grinder includes a constant tangent angle control module and a support lifting mechanism. The constant tangent angle control module is mainly used to lock the angle of the tangent angle and calculate the actual required workpiece center height based on the actual size of the grinding wheel and guide wheel. The support lifting mechanism is used to adjust the workpiece center height to the actual position.

[0009] As shown in Figure 2, set the parameter "New Grinding Wheel Diameter," and the system will automatically subtract twice the "Grinding Wheel Wear Amount" to obtain the "Current Grinding Wheel Diameter." Each time the grinding wheel is dressed, the "Grinding Wheel Wear Amount" will automatically accumulate and does not need to be set. When replacing the grinding wheel, execute the "Return to New Grinding Wheel" action, and the "Grinding Wheel Wear Amount" will be reset to zero.

[0010] Similarly, by setting the "new guide wheel diameter" parameter, the system will automatically subtract twice the "guide wheel wear amount" to obtain the "current guide wheel diameter." Each time the guide wheel is overhauled, the "guide wheel wear amount" will automatically accumulate in the system and does not need to be set. When replacing the guide wheel, the "guide wheel wear amount" will be reset to zero by performing the "replace guide wheel" action.

[0011] The workpiece diameter is known and needs to be entered in the parameters.

[0012] Based on the applicant's extensive data statistics, the optimal range of the tangent angle at the contact point between the workpiece and the grinding wheel / guide wheel is 6 to 8 degrees. Here, we substitute the intermediate value of 7 degrees and calculate the theoretical center height h0 of the workpiece according to formula (1). Where R0 is the theoretical value of the tangent angle at the contact point between the workpiece and the grinding wheel / guide wheel, and D... RW D is the diameter of the guide wheel. GW D is the diameter of the grinding wheel. WK The diameter is the workpiece diameter.

[0013] Input the parameter h0, and then start the trial grinding of the workpiece. Keep the linear speed of the grinding wheel and the linear speed of the guide wheel constant. Adjust the tangent angle according to the shape of the workpiece. Specifically: if the workpiece is prismatic (polygonal), it means that the tangent angle is too large and the center height h needs to be reduced. If the workpiece is elliptical or the workpiece jumps in the grinding area, it means that the tangent angle is too small and the center height h needs to be increased. At this time, if the "tangent angle lock" button on the control interface is not locked, the center height can be slightly adjusted by using the positive and negative fine adjustment buttons on the screen to raise or lower the bracket using the bracket lifting mechanism. In the trial grinding state, the diameter of the grinding guide wheel and the workpiece remains unchanged until a qualified product is ground. The actual tangent angle R is deduced from the formula (2). After determining the tangent angle R, obtain the current center height value according to formula (1), and press the "Tangent Angle Lock" button to lock the tangent angle. At this time, the positive and negative fine adjustment buttons on the operation interface are invalid.

[0014] The workpiece is then ground to obtain a qualified product by constantly controlling the linear speed of the grinding wheel, the linear speed of the guide wheel, and the tangent angle.

[0015] The following is a detailed explanation of the grinding wheel diameter D. GW The guide wheel diameter is 600 mm. RW The diameter D of the workpiece being ground is 350 mm.WK For a workpiece of 30 mm. Considering that the optimal range of the tangent angle between the workpiece and the contact point of the grinding wheel and guide wheel is 6 to 8 degrees, we substitute the middle value of 7 degrees into R. According to formula (1), we can calculate the theoretical value of the center height h0 as 14.47. Then, using the calculated theoretical value of the center height h0 as 14.47, the grinding wheel D GW 600 mm, guide wheel diameter D RW 350 mm, grinding workpiece diameter D WK For a 30 mm workpiece, by adjusting the center height h, the actual value R of the tangent angle at the contact point between the workpiece and the grinding wheel and guide wheel is calculated according to formula (2). Repeated trial grinding is performed, and the center height h of the workpiece is adjusted until qualified products are produced in batches. It is worth mentioning that at this time, the tangent angle R will change with the change of the center height of the workpiece.

[0016] With each dressing of the grinding wheel and guide wheel, the diameter of the grinding wheel and guide wheel changes. The system still calculates the value of the center height h in real time and adjusts the center height through a high-precision centerless grinding support lifting mechanism.

[0017] As shown in Figures 3 and 4, the bracket lifting mechanism includes a bracket body 1 and a worktable base 2. A worktable support plate 3 is provided between the bracket body 1 and the worktable base 2. The bottom of the bracket body 1 and the top of the worktable support plate 3 are in a horizontal sliding fit, while the bottom of the worktable support plate 3 and the top of the worktable base 1 are in a wedge fit. Specifically, a dovetail-shaped wedge guide rail is used, and inserts are added to ensure a tight fit and allow for appropriate adjustment of the tightness. The bottom of the worktable support plate 3 is connected to an inclined ball screw 5 via a screw nut 4. The ball screw 5 is connected and installed... A harmonic reducer 11 is also provided between the servo motor 6 on the worktable base 2, the ball screw 5 and the output shaft of the servo motor 6, for precise control of displacement. A vertical guide mechanism is provided between the bracket body 1 and the worktable base 2. The vertical guide mechanism includes a vertical guide rod 8 fixed on the worktable base 2 and a guide block 9 fixed on the bracket body 1. A guide rod seat 10 for fixing the vertical guide rod 8 is installed on the worktable base 2. The vertical guide rod 8 passes through the guide block 9 and is slidably engaged, ensuring that there is only a change in height between the bracket body 1 and the worktable base plate 3, and the lateral position remains unchanged.

[0018] To achieve good waterproofing, the servo motor 6 is equipped with a motor cover 12. The servo motor 6 is connected to the workbench base 2 through the motor base 13. An accordion-style protective cover 14 is provided between the upper end of the motor base 13 and the workbench support plate 3. Rubber water-blocking sheets 15 are installed around the bracket body 1.

[0019] A position sensor transmitting module 16 and a position sensor receiving module 7 are provided between the bracket body 1 and the workbench base 2 to determine the lifting position of the bracket body 1.

[0020] The bracket body 1 includes a guide wheel seat 1-1. The front and rear ends of the guide wheel seat 1-1 are respectively set on the front bracket 1-2 and the rear bracket 1-3. The front bracket 1-2 and the rear bracket 1-3 are connected to the support plate 1-4. The support plate 1-4 is equipped with a guide plate 1-5.

[0021] The servo motor 6 drives the ball screw 5 to rotate, and the screw nut 4 moves on the ball screw 5. When it tilts downward, it moves the worktable support plate 3 to the left and the height of the upper end face decreases, causing the bracket body 1 to descend. When it tilts upward, it moves the worktable support plate 3 to the right and the height of the upper end face increases, causing the bracket body 1 to rise. The center height of the workpiece changes with the descent or rise of the bracket body 1.

[0022] This invention innovatively employs a "three-constant control" method: constant grinding wheel linear speed control: ensuring that even if the grinding wheel diameter is reduced due to dressing, the grinding linear speed on its surface remains constant. This is crucial for ensuring the grinding quality, surface finish, and stability of the machining process.

[0023] Constant linear speed control of guide wheels: Similarly, constant linear speed control is also implemented for guide wheels to maintain stable workpiece rotation and feed.

[0024] Constant tangent angle control grinding: During the grinding process, as the diameter of the grinding wheel and guide wheel decreases due to dressing, the machine tool can automatically adjust the height of the support plate to keep the tangent angle between the workpiece and the contact point of the grinding wheel and guide wheel constant.

[0025] This control strategy, through comprehensive regulation of machine tool settings, process parameters, and grinding conditions, strives to ensure that the interaction and grinding geometry between the grinding wheel, guide wheel, support plate, and workpiece are always in the optimal state, which is the key to achieving high-quality centerless grinding.

Claims

1. A constant tangential angle grinding control system for a centerless grinder, characterized in that, This includes a constant tangent angle control module and a bracket lifting mechanism. The constant tangent angle control module calculates the theoretical center height h0 of the workpiece. Where R0 is the theoretical value of the tangent angle at the contact point between the workpiece and the grinding wheel / guide wheel, and D... RW D is the diameter of the guide wheel. GW D is the diameter of the grinding wheel. WK The workpiece diameter is set; then, the workpiece is test-ground, with the grinding wheel and guide wheel linear speeds kept constant. The support lifting mechanism adjusts the workpiece center height h according to the workpiece shape to fine-tune the tangent angle R until a qualified product is produced, thus obtaining the precise value of the tangent angle R. After determining the tangent angle R, the current center height value is obtained according to formula (1). Subsequently, the workpiece is ground to obtain a qualified product by constant control of the grinding wheel linear speed, constant control of the guide wheel linear speed and constant control of the tangent angle.

2. The constant tangential angle grinding control system for a centerless grinder according to claim 1, characterized in that, The bracket lifting mechanism includes a bracket body and a worktable base. A worktable support plate is provided between the bracket body and the worktable base. The bottom of the bracket body and the top of the worktable support plate are in a horizontal sliding fit, while the bottom of the worktable support plate and the top of the worktable base are in a wedge fit. The bottom of the worktable support plate is connected to an inclined ball screw via a screw nut. The ball screw is connected to a servo motor mounted on the worktable base. A vertical guide mechanism is provided between the bracket body and the worktable base. The servo motor drives the ball screw, allowing the worktable support plate to change height along the wedge guide rail. The vertical guide mechanism restricts the movement of the bracket body in the height direction, and the center height of the workpiece on the bracket can be freely adjusted.

3. The constant tangential angle grinding control system for a centerless grinder according to claim 1, characterized in that, The bottom of the workbench support plate and the bottom of the workbench base are connected by a dovetail-shaped wedge guide rail. A harmonic reducer is provided between the ball screw and the output shaft of the servo motor. The servo motor is covered by a motor housing.

4. The constant tangential angle grinding control system for a centerless grinder according to claim 1, characterized in that, The servo motor is connected to the workbench base via a motor mount. An accordion-style protective cover is provided between the upper end of the motor mount and the workbench support plate. Rubber water-blocking sheets are installed around the main body of the bracket.

5. A constant tangential angle grinding control system for a centerless grinder according to claim 1, characterized in that, The vertical guide mechanism includes a vertical guide rod fixed to the workbench base and a guide block fixed to the bracket body. The vertical guide rod passes through the guide block and is slidably engaged.

6. The constant tangential angle grinding control system for a centerless grinder according to claim 1, characterized in that, A position sensor transmitting module and a position sensor receiving module are provided between the bracket body and the workbench base.

7. A constant tangential angle grinding control system for a centerless grinder according to claim 1, characterized in that, The bracket body includes a guide wheel seat, with the front and rear ends of the guide wheel seat respectively disposed on the front support and the rear support. The front support and the rear support are connected to a support plate, and a guide plate is installed on the support plate.

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