Double-screw rod synchronous spindle feeding drive system of double-sided grinding machine

Abstract

A dual-screw synchronous feed drive system for a double-sided grinding machine includes a main support, a spindle and its components, and two sets of feed drive units. Two sets of linear guide pairs are centrally distributed on both sides of the spindle assembly. The two sets of feed drive units are symmetrically arranged along the main support and form an isosceles right-angled triangle with the central axis of the spindle. The feed drive units are a first feed drive unit and a second feed drive unit with identical structures. The first feed drive unit includes a ball screw and a ball nut, with the ball nut fixed to a nut seat. This invention improves the feed accuracy of the spindle assembly; ensures the stability of grinding operations; effectively reduces screw wear and maintains a stable grinding wheel angle; improves the positioning accuracy and repeatability of the machine tool; resolves the contradiction between high rigidity and high precision; and greatly improves grinding efficiency and accuracy.

Description

Technical Field

[0001] This invention relates to a drive system, specifically to a dual-screw synchronous feed drive system for a double-sided grinding machine. Background Technology

[0002] Currently, the feed mechanism of double-end grinding machines, both domestically and internationally, generally uses hollow ball screws for guidance and feed drive. The grinding head moves up and down through a hollow, large-diameter ball screw concentric with the spindle and a worm gear structure to achieve grinding. This structure of double-end grinding machines is prone to defects such as insufficient grinding head rigidity and easy wear of the ball screw.

[0003] CN 216066714 U describes a novel feed mechanism for a double-end grinding machine. This mechanism solves the manufacturing difficulty of hollow, large-diameter ball screws by using a conventional lead screw guide system. The grinding head feed mechanism uses a ball screw and ball nut to move the grinding head assembly up and down relative to the housing. However, in this design, the lead screw is positioned behind the spindle. When the double-end grinding machine is grinding a workpiece, it only passes through a portion of the grinding wheel area, specifically the front 1 / 3 region. This rearward placement of the lead screw causes the spindle box and linear guide pair to bear a large overturning moment, easily leading to spindle tilting. Especially under stress, the grinding wheel area is more prone to slippage or elastic deformation, affecting the spindle rigidity and causing grinding instability. Particularly during heavy-duty grinding (workpieces with large grinding allowances), dimensional instability can occur, resulting in workpiece exit finishing (inconsistent workpiece dimensions). Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a dual-screw synchronous feed drive system for a double-sided grinding machine that can improve the overall rigidity and feed accuracy of the spindle assembly.

[0005] The technical solution adopted by this invention to solve its technical problem is a dual-screw synchronous feed drive system for a double-sided grinding machine, including a main support, a spindle and its components, and two sets of feed drive units. Two sets of linear guide pairs are provided on both sides of the spindle assembly, distributed along the center. The two sets of feed drive units are symmetrically arranged along the main support and distributed in an isosceles right-angled triangle with the central axis of the spindle.

[0006] The feed drive units are a first feed drive unit and a second feed drive unit with identical structures.

[0007] The first feed drive unit includes a ball screw and a ball nut, the ball nut being fixed on a nut seat, and the nut seat being disposed on the spindle assembly;

[0008] The central axis of the ball nut of the first feed drive unit and the central axis of the ball nut of the second feed drive unit are set parallel to the central axis of the main shaft and its components, and the line connecting the three points on the same plane forms an isosceles right triangle structure.

[0009] The main support is provided with a slider of linear guide pair, and the main shaft and its components are respectively provided with guide rails of linear guide pair on both sides. The two sets of linear guide pairs are arranged opposite to each other, and their centers coincide with the center of the main shaft assembly.

[0010] It also includes a control system, which includes a processor system and a grating ruler for measuring the spindle feed stroke. The signal output terminal of the grating ruler is connected to the signal input terminal of the CNC system.

[0011] Furthermore, the main support consists of an upper support, a left support, and a right support. The left and right supports are respectively provided with sliders for linear guide pairs. The upper support, left support, and right support are symmetrically provided with slider mounting surfaces.

[0012] Furthermore, the spindle and its components have guide rail mounting surfaces on both sides of the spindle box, and the guide rails of the two linear guide rail pairs are rigidly connected to both sides of the spindle and its components. The spindle and its components have two planar nut seat mounting surfaces distributed at a 45-degree angle at the front, and the nut seats are rigidly connected to the spindle and its components.

[0013] Furthermore, the ball screw passes through the ball nut, and a first support bearing is provided at the first end of the ball screw. The upper support has two holes, the center lines of which coincide with the center axes of the two screws respectively. The ball screw and the first support bearing are coaxially fixed in the hole of the first support seat by the first nut, and the ball screw and the second support bearing are coaxially fixed in the hole of the upper support seat by the second nut, forming an axial and radial fixed support.

[0014] Furthermore, the two lead screw center axes and the spindle center axis form an isosceles right triangle structure, and the two lead screw center axes are located at the vertices of the hypotenuse of the right triangle. The linear guide pair is installed on the left and right sides of the spindle. The two lead screw center axes are on the same side as the grinding wheel grinding area.

[0015] Furthermore, the grating ruler measures the travel of the lead screw drive system to provide real-time feedback on the execution of the lead screw drive system's actions. Using CNC high-speed bus communication technology, the communication scanning cycle between the control system and the servo drive is controlled within 1ms. By enabling gantry axis synchronous control technology, dual lead screw synchronous control is achieved. This synchronization function also supports flexible synchronous automatic adjustment. When enabled, if the drive shaft and driven shaft have slight deviations, the system will activate the automatic adjustment function to keep the synchronization error within the allowable range.

[0016] The dual-screw synchronous feed drive system for a double-sided grinder in this invention features a guide rail pair connection center that coincides with the spindle center. The centers of the dual screws are distributed at a triangular angle to the spindle center, and the centers of the dual screws coincide with the force-bearing area of ​​the grinding wheel during grinding. This enhances the load-bearing capacity and ensures that the center of gravity of the spindle assembly coincides with its linear motion center, preventing the spindle assembly from experiencing large overturning torques. This improves the rigidity of the double-sided grinder and enhances the feed accuracy of the spindle assembly. The dual-screw drive system enables the feed of the upper spindle assembly. The rational arrangement of force-bearing points improves the rigidity of the feed system during grinding, ensuring the stability of the grinding process. The dual screws jointly bear the weight of the upper grinding head spindle, effectively reducing screw wear and maintaining a stable grinding wheel angle. This improves the machine tool's positioning accuracy and repeatability, resolving the contradiction between high rigidity and high precision, and significantly enhancing grinding efficiency and accuracy. Attached Figure Description

[0017] Figure 1 This is a three-dimensional schematic diagram of an embodiment of the present invention;

[0018] Figure 2 This is a top view schematic diagram of an embodiment of the present invention;

[0019] Figure 3 This is a partial cross-sectional view of an embodiment of the present invention;

[0020] Figure 4 This is a three-dimensional schematic diagram of the spindle and its components according to an embodiment of the present invention;

[0021] Figure 5 This is a side view of the structure according to an embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of the stress structure according to an embodiment of the present invention.

[0023] In the diagram: 1. Upper support 2. Left support 3. Lower support 4. Grating ruler 4.1 Reading head 4.2 Grating ruler body 5. Feed unit 6. Feed unit 7. Spindle and its components 8. Linear guide pair 8.1 Slider 8.2 Guide rail (linear guide pair) 9. Workpiece 10. Fixture 10.1 Fixture outer ring 50.1 Lead screw (ball screw pair) 50.2 Ball nut (ball screw pair) 50.3 Nut seat 50.4 Second bearing 50.5 Precision reducer 50.6 Servo motor 50.7 First bearing seat 50.8 First bearing 50.9 First locking nut 51.2 Second locking nut 71. Guide rail surface of spindle box 72. Nut seat mounting surface of spindle box 73. Grinding wheel 73.1 Grinding wheel outer ring 73.2 Grinding wheel inner ring. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0025] See attached document Figure 1-2 This embodiment includes a main support consisting of an upper support 1, a left support 2, and a right support 3; a main shaft and its assembly 7; two sets of linear guide rail pairs 8 distributed along the center of both sides of the main shaft and its assembly 7; and two identical feed drive units arranged symmetrically along the main support (upper support 1, left support 2, right support 3) and distributed in an isosceles right triangle with the central axis O1 of the main shaft, namely the first feed drive unit 5 and the second feed drive unit 6.

[0026] The first feed drive unit 5 and the second feed drive unit 6 include a ball screw (501) and a ball nut (502). The ball nut (502) is fixed on a nut seat (503). The nut seat (503) is disposed on the spindle and its assembly (7). The central axes O2 and O3 of the ball nut (502) are parallel to the central axis O1 of the spindle and its assembly (7).

[0027] The ball screw (501) passes through the ball nut (502). The first end of the screw (501) is provided with a first support bearing (508). The first support bearing (508) is fixed on the first bearing seat 507. The upper support (1) is provided with two holes. The center lines of the two holes coincide with the axes O2 and O3 respectively. The ball screw (501) and the first support bearing (508) are coaxially fixed in the hole of the first support seat (507) through the first nut 510. The ball screw (501) and the second support bearing (504) are coaxially fixed in the hole of the upper support (1) through the second nut 509, forming an axial and radial fixed support.

[0028] like Figure 2 As shown, the lines connecting the two lead screw center axes (O2, O3) and the spindle center axis (O1) form an isosceles right triangle, with the two lead screw center axes (O2, O3) located at the vertices of the hypotenuse of the right triangle. Linear guide pairs 8 are installed on the left and right sides of the spindle, with O1 (spindle center), O2 (left lead screw center), and O3 (right lead screw center). The two lead screw center axes (O2, O3) are on the same side as the grinding wheel's grinding area.

[0029] The upper support 1, left support 2, and right support 3 are rigidly connected. The left support 2 and right support 3 are each equipped with a slider 82 of a linear guide pair 8. The main spindle assembly 7 has guide rails 81 of the linear guide pair 8 on both sides. The two sets of linear guide pairs 8 are arranged opposite each other, with their centers coinciding with the center of the main spindle assembly 7. Figure 2 The main supports shown (upper support 1, left support 2, right support 3) are symmetrically equipped with slider mounting surfaces on both sides, as shown. Figure 4As shown, the spindle assembly 7 has guide rail mounting surfaces 71 on both sides of the spindle box, and the guide rails 82 of the two linear guide rail pairs are rigidly connected to the two sides of the spindle box of the spindle assembly 7. The spindle assembly 7 has two planar nut seat mounting surfaces 62 distributed at a 45-degree angle at the front, and the nut seats 503 are rigidly connected to the spindle assembly 7.

[0030] The motion process of this invention is as follows:

[0031] The servo motor (506) drives the spindle assembly 7 to move axially within the fixed slider 82 following the guide rail 81 through the two sets of feed drive units (5, 6).

[0032] The spindle synchronous feed drive system of the double-sided grinding machine, wherein the output end of the precision reducer (505) has a bellows output shaft and a hole for locking the lead screw end.

[0033] like Figure 1 As shown, this embodiment includes a control system, which includes a processor system and a grating ruler 4 for measuring the spindle feed stroke. The signal output terminal of the grating ruler 4 is connected to the signal input terminal of the CNC system (not shown in the figure). The grating ruler 4 measures the stroke of the lead screw drive system to provide real-time feedback on the execution status of the lead screw drive system. High-speed CNC bus communication technology is used to control the communication scan cycle between the control system and the servo drive within 1ms. Synchronous control of the dual lead screws is achieved by enabling gantry axis synchronization control technology. This synchronization function also supports flexible automatic synchronization adjustment; when enabled, the system will automatically adjust to keep the synchronization error within an allowable range when slight deviations occur between the drive and driven axes.

[0034] like Figure 5 As shown in Figure 6, when the double-sided grinder is working, the grinding area is enclosed by the grinding wheel 73 and fixtures 101 and 102 of the clamp 10. When the fixture rotates and continuously places the workpiece into the grinding area, the force in this area is F1. The resultant force of the output forces F2 and F3 from the ball screw 501 in the first feed drive unit 5 and the second feed drive unit 6 is usually considered to be a rigid body. Therefore, the resultant forces of F1 and F2 and F3 just cancel each other out, and there will be no spindle deformation due to eccentric load. At the same time, it also extends the life of the guide rail. In the existing design, the center O4 of the screw is arranged behind the grinding wheel (e.g., Figure 6In the non-grinding area, F1 and F4 are located on either side of the spindle center and guide rail center, respectively. When F1 is upward and F4 is downward, the spindle center acts as a fulcrum, causing deformation with one end upward and the other downward, and L2 > L1. The bending moment M = F × L. When the lead screw is placed on the rear side, it is more prone to deformation under grinding force, resulting in weaker rigidity. The structural arrangement of this invention significantly improves the overall rigidity of the spindle and avoids inconsistent workpiece dimensions after grinding during heavy-duty grinding.

[0035] In summary, the dual-screw synchronous feed drive system of the double-sided grinder of this embodiment places the spindle assembly 7 inside the main support. The upper support 1, left support 2, and right support 3 are arranged and connected to the spindle assembly 7 with the linear guide pair 8. The main support is connected to the slider 82, and the spindle assembly 7 is connected to the guide rail 81. The main support is fixed to the bed of the double-sided grinder (not shown) to form a fixed rigid body. The spindle assembly and the guide rail are connected through the dual-screw feed unit 5 (6). Under the drive of the servo motor 506, and further under the action of the ball screw 501 and the ball nut 502, the two nut seats 503 are driven and the spindle assembly 7 moves up and down along the slider 82 in the Z-axis direction under the constraint of the linear guide pair 8. At this time, the center of gravity of the moving part, namely the spindle assembly 7, coincides with its center of motion, and the force-bearing end and the load-bearing end are in the same area. There is no overturning torque, which improves the overall rigidity of the double surface grinder. In addition, the two lead screws move synchronously in the system, so that the forces at both ends of the spindle assembly 7 are balanced, and there will be no uneven load. The movement is more stable, the feed dynamic characteristics are good, and the machining accuracy of the machine tool is high.

[0036] Although the above embodiments only describe a vertical double-surface grinder where the grinding wheel's rotation axis is in the vertical direction, the present invention is not limited thereto. For example, it can also be applied to a horizontal double-surface grinder where the grinding wheel's rotation axis is in the horizontal direction.

[0037] Those skilled in the art can make various modifications and variations to this invention. If such modifications and variations are within the scope of the claims of this invention and their equivalents, then such modifications and variations are still within the protection scope of this patent.

[0038] The contents not described in detail in the specification are prior art known to those skilled in the art.

Claims

1. A dual-screw synchronous feed drive system for a double-sided grinding machine, comprising a main support, a spindle, and its components, characterized in that: It also includes two sets of feed drive units. The spindle assembly has two sets of linear guide pairs distributed along the center on both sides. The two sets of feed drive units are symmetrically arranged along the main support and are distributed in an isosceles right triangle with the central axis of the spindle. The feed drive units are a first feed drive unit and a second feed drive unit with identical structures. The first feed drive unit includes a ball screw and a ball nut, the ball nut being fixed on a nut seat, and the nut seat being disposed on the spindle assembly; The central axis of the ball nut of the first feed drive unit and the central axis of the ball nut of the second feed drive unit are set parallel to the central axis of the main shaft and its components, and the line connecting the three points on the same plane forms an isosceles right triangle structure. The main support is provided with a slider of linear guide pair, and the main shaft and its components are respectively provided with guide rails of linear guide pair on both sides. The two sets of linear guide pairs are arranged opposite to each other, and their centers coincide with the center of the main shaft assembly. It also includes a control system, which includes a processor system and a grating ruler for measuring the spindle feed stroke. The signal output terminal of the grating ruler is connected to the signal input terminal of the CNC system.

2. The dual-screw spindle synchronous feed drive system for a double-sided grinding machine according to claim 1, characterized in that: The main support consists of an upper support, a left support, and a right support. The left and right supports are each provided with a slider of a linear guide pair. The upper support, the left support, and the right support are symmetrically provided with slider mounting surfaces.

3. The dual-screw spindle synchronous feed drive system for a double-sided grinding machine according to claim 1 or 2, characterized in that: The spindle and its components have guide rail mounting surfaces on both sides of the spindle box. The guide rails of the two linear guide rail pairs are rigidly connected to both sides of the spindle and its components. The spindle and its components have two planar nut seat mounting surfaces distributed at 45 degrees at the front. The nut seats are rigidly connected to the spindle and its components.

4. The dual-screw spindle synchronous feed drive system for a double-sided grinding machine according to claim 1 or 2, characterized in that: The ball screw passes through the ball nut. The first end of the ball screw is provided with a first support bearing. The upper support is provided with two holes. The center lines of the two holes coincide with the center axes of the two screws respectively. The ball screw and the first support bearing are coaxially fixed in the hole of the first support seat through the first nut. The ball screw and the second support bearing are coaxially fixed in the hole of the upper support seat through the second nut, forming an axial and radial fixed support.

5. The dual-screw spindle synchronous feed drive system for a double-sided grinding machine according to claim 1 or 2, characterized in that: The two lead screws' central axes and the spindle's central axis form an isosceles right triangle, with the two lead screws' central axes located at the vertices of the hypotenuse of the right triangle. The linear guide pairs are installed on the left and right sides of the spindle. The two lead screws' central axes are on the same side as the grinding wheel's grinding area.

6. The dual-screw spindle synchronous feed drive system for a double-sided grinding machine according to claim 1 or 2, characterized in that: The grating ruler measures the travel of the lead screw drive system to provide real-time feedback on the system's operation. Utilizing high-speed CNC bus communication technology, the communication scan cycle between the control system and the servo drive is controlled within 1ms. Dual lead screw synchronous control is achieved by enabling gantry axis synchronous control technology. This synchronization function also supports flexible automatic synchronous adjustment; when the drive and driven axes exhibit slight deviations, the system will automatically adjust to keep the synchronization error within acceptable limits.

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