Pre-tightening force stabilizing device for linear ultrasonic motor driving platform

Abstract

The invention relates to the technical field of ultrasonic motor driving, and particularly discloses a pre-tightening force stabilizing device for a linear ultrasonic motor driving platform, the device provides an automatic compensation structure based on a double-spring synergistic effect, the automatic compensation structure comprises a main body, a conduction assembly and a compensation assembly, the conduction assembly is composed of a connecting plate with an inclined groove, an inclined block and a guide column, transverse displacement is converted into longitudinal jacking movement; the compensation assembly comprises a longitudinal spring set for providing main pre-tightening force and a transverse spring set for clearance compensation. When a driving foot is abraded to generate a gap, the transverse spring pushes the inclined block to slide along the inclined groove to drive the stator to move upwards to compensate the gap, the compression amount of the longitudinal spring is almost unchanged, and the pre-tightening force loss is extremely small; according to the device, automatic compensation of the abrasion clearance is realized, the operation reliability and the positioning precision of the motor are improved, and the maintenance period is prolonged.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic motor drive technology, and more specifically to a preload stabilizing device for a linear ultrasonic motor drive platform. Background Technology

[0002] As a new type of motor based on the inverse piezoelectric effect of piezoelectric ceramics and the principle of friction drive, the performance of ultrasonic motors is highly dependent on the preload at the contact interface between the stator and the mover. Therefore, reliable and stable preload is the core key to ensuring the efficient and stable operation of ultrasonic motors.

[0003] Existing ultrasonic motor preload control schemes generally adopt a "single longitudinal spring" structure: that is, a spring is set in the normal pressure direction (vertical direction) between the stator and the mover, and the initial preload is provided by the pressure of the spring. However, this scheme has significant drawbacks: after long-term operation of the ultrasonic motor, the drive feet on the stator will wear due to repeated friction, forming a "wear gap"; to compensate for this gap, the longitudinal spring needs to be further extended, which leads to a sharp decrease in the compression of the longitudinal spring and a significant loss of preload; when the loss of preload exceeds the critical value, the contact pressure between the stator and the mover (i.e., preload) is insufficient, which will directly cause problems such as slippage, sudden drop in output force, and decrease in positioning accuracy, seriously affecting the stability of the drive platform, and even causing equipment shutdown for maintenance. Summary of the Invention

[0004] In view of the problem that the reduction in spring compression directly leads to a decrease in preload and poor stability when the existing ultrasonic motor preload device uses a "single longitudinal spring" to compensate for wear gaps, the purpose of this invention is to provide a preload stabilizing device for a linear ultrasonic motor drive platform, which realizes automatic compensation for wear gaps and significantly reduces preload loss.

[0005] A preload stabilizing device for a linear ultrasonic motor drive platform includes a main body, a mover slidably connected to the top of the main body, and a stator abutting the bottom of the mover via symmetrically placed driving feet. The device also includes: The transmission assembly includes a lifting member fixedly connected to the stator and a force transmission member slidably connected to the lifting member; the lifting member is slidably connected to the main body via a guide member below, the thickness of the force transmission member gradually increases, and the guide member is used to limit the vertical movement of the lifting member; The compensation component includes a longitudinal elastic element disposed below the force transmission element and a transverse elastic element fixed to one side of the force transmission element; the end of the longitudinal elastic element away from the force transmission element is fixedly connected to the main body, and the end of the transverse elastic element away from the force transmission element is slidably connected to the main body. The stiffness of the transverse elastic element is less than that of the longitudinal elastic element, and the transverse elastic element is initially in a compressed state to always apply a transverse thrust to the force transmission element. The force transmission element is driven by the force to raise the lifting element to compensate for the wear gap.

[0006] As a further improvement of this application, the lifting member includes a connecting plate; the bottom of the connecting plate is provided with an inclined groove.

[0007] As a further improvement of this application, the force transmission component is an inclined block with a beveled surface, and the inclined block is slidably connected to the inclined groove through the beveled surface.

[0008] As a further improvement of this application, the guide includes guide posts symmetrically arranged on the inner wall of the bottom of the main body and guide holes correspondingly opened at the bottom of the connecting block; the guide posts slide within the copper sleeve in the guide holes.

[0009] As a further improvement of this application, the longitudinal elastic element includes multiple sets of longitudinal telescopic rods vertically distributed below the inclined block, longitudinal springs respectively sleeved on the outer wall of the longitudinal telescopic rods and in a compressed state, and support plates and a first mounting plate respectively fixed to the top and bottom of the longitudinal telescopic rods; the two ends of the longitudinal springs abut against the support plate and the first mounting plate respectively, the support plate abuts against the bottom of the inclined block, and the first mounting plate is fixed in the bottom groove opened in the main body base.

[0010] As a further improvement of this application, the lateral elastic member includes a lateral limiting rod fixed to one side of the inclined block, a lateral spring sleeved on the outer wall of the lateral limiting rod and in a compressed state, and a limiting ring sliding on the lateral limiting rod; the end of the lateral limiting rod away from the inclined block slides in a vertical groove opened in the side wall of the main body, a second mounting plate is provided between the inclined block and the lateral limiting rod, the two ends of the lateral spring respectively abut against the second mounting plate and the limiting ring, and the side of the limiting ring away from the lateral spring contacts the inner side wall of the main body.

[0011] As a further improvement to this application, the angle between the inclined plane of the inclined block and the horizontal plane is set to 15°.

[0012] As a further improvement of this application, piezoelectric ceramic sheets are bonded to both the upper and lower surfaces of the stator. When the piezoelectric ceramic sheets are energized, the stator vibrates accordingly through the inverse piezoelectric effect.

[0013] As a further improvement of this application, a grating head is fixed to the bottom of the mover by a fixing plate, and a grating ruler is glued to the corresponding outer wall of the main body. The grating ruler and the grating head move closer and further apart as the mover slides to measure speed.

[0014] In summary, compared with the prior art, the beneficial effects of the present invention are: This invention utilizes a "conduction-compensation" synergistic structure and a functional separation design of dual elastic components: By employing the synergistic effect of the transverse elastic element and the inclined block and inclined groove transmission mechanism, the restoring thrust of the transverse elastic element is converted into the longitudinal lifting displacement of the stator, automatically compensating for the gap caused by the wear of the drive foot. During this process, the compression of the longitudinal elastic element changes very little, thus keeping the preload it provides essentially constant. Compared with the existing "single longitudinal spring" scheme, which suffers a significant loss of preload when compensating for the gap, this device fundamentally avoids subsequent problems such as slippage, reduced output force, and deterioration of positioning accuracy caused by insufficient preload. The dual-elastic component structure is specialized: the longitudinal elastic component mainly provides stable preload, while the transverse elastic component mainly undertakes the function of gap compensation. The design makes the stiffness of the transverse elastic component less than that of the longitudinal elastic component, ensuring that the loss of preload is minimized when compensating for the same wear gap. Compared with the traditional single spring solution that provides both preload and gap compensation, this approach is more optimized in terms of mechanical principles and significantly improves efficiency. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is another overall structural schematic diagram of the present invention; Figure 3 For the present invention Figure 2 Enlarged view of part A; Figure 4 This is a cross-sectional side view of the overall structure of the present invention; Figure 5 This is a front cross-sectional view of the overall structure of the present invention; Figure 6 This is a schematic diagram showing the structure and positional relationship of the conductive component and the compensation component of the present invention.

[0016] Explanation of the labels in the diagram: 1-Main body, 101-Bottom groove, 102-Vertical groove, 103-Guide rail, 2-Longitudinal spring, 3-Longitudinal telescopic rod, 4-First mounting plate, 5-Support plate, 6-Transverse spring, 7-Transverse limiting rod, 8-Limiting ring, 9-Inclined block, 901-Beveled surface, 10-Connecting plate, 11-Guide hole, 12-Guide post, 1001-Inclined groove, 13-Stator, 1301-Piezoelectric ceramic sheet, 14-Fixing block, 15-Drive foot, 16-Moving element, 17-Slider, 18-Grate head, 19-Grate ruler, 20-Second mounting plate, 21-Fixing plate, 22-Copper sleeve. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] Example 1: This embodiment discloses a preload stabilizing device for a linear ultrasonic motor drive platform. It aims to solve the technical problem in existing ultrasonic motor preload schemes where long-term friction and wear of the drive foot 15 creates gaps, leading to a decrease in spring compression and a significant loss of preload, resulting in slippage, a sudden drop in output force, and reduced positioning accuracy. This device is suitable for linear ultrasonic motor drive scenarios with stringent precision requirements, such as precision machine tool feed systems, semiconductor wafer handling platforms, and optical component positioning devices. It achieves automatic compensation of wear gaps through a "conduction-compensation" collaborative structure, ensuring long-term stability of the preload and improving motor operational reliability and maintenance cycles. See also... Figures 1 to 6 The device includes a main body 1, a transmission component, and a compensation component. A mover 16 is slidably connected to the top of the main body 1, and a stator 13 is abutted against the bottom of the mover 16 via symmetrically placed driving feet 15. It also includes... The transmission assembly includes a lifting member fixedly connected to the stator 13 and a force transmission member slidably connected to the lifting member; the lifting member is slidably connected to the main body 1 below through a guide member, the thickness of the force transmission member gradually increases, and the guide member is used to limit the vertical movement of the lifting member; The compensation component includes a longitudinal elastic element disposed below the force transmission component and a transverse elastic element fixed to one side of the force transmission component; the end of the longitudinal elastic element away from the force transmission component is fixedly connected to the main body 1, and the end of the transverse elastic element away from the force transmission component is slidably connected to the main body 1; the stiffness of the transverse elastic element is less than that of the longitudinal elastic element, and the transverse elastic element is in a compressed state to always apply a transverse thrust to the force transmission component; the force transmission component is driven by the force to raise the lifting component to compensate for the wear gap.

[0020] Preferably, the top of the main body 1 is fixedly connected with two sets of symmetrically distributed guide rails 103 by bolts, and the bottom of the mover 16 is fixed with four symmetrically distributed sliders 17 by bolts. The mover 16 is slidably connected to the guide rails 103 through the sliders 17. The stator 13 is "H" shaped, and the top of the stator 13 is riveted and fixed with left and right symmetrical fixing blocks 14. The top of the fixing blocks 14 is respectively glued with driving feet 15. The driving feet 15 are "elliptical" in shape, and their tops are in contact with the mover 16. The vibration generated by the stator 13 is transmitted to the mover 16 through the driving feet 15, so that the mover 16 reciprocates linearly with the guide rails 103. The inner wall of the base of the main body 1 is provided with a bottom groove 101. A longitudinal elastic element is fixed in the bottom groove 101 by bolts. A vertical groove 102 is provided through the side wall of the main body 1. The transverse elastic element slides in the vertical groove 102. It should be noted that the function of the transverse elastic element is to compensate for the wear gap, while the function of the longitudinal elastic element is to provide preload. When a wear gap occurs, the elastic forces of the transverse and longitudinal elastic elements will change accordingly to achieve a new static equilibrium. Specifically, when wear gaps occur, the compression of the transverse elastic element decreases, and the transverse elastic element spontaneously pushes the inclined block 9, which is fixedly connected to it, to move horizontally. Through the sliding structure of the inclined block 9 and the inclined groove 1001, the stator 13 is driven to rise sequentially, and finally the driving foot 15 on the stator 13 moves the corresponding distance in the vertical direction. That is, the transverse elastic element automatically compensates for the wear gaps caused by long-term wear of the driving foot 15.

[0021] Further, see Figure 6 The lifting component includes a connecting plate 10; the bottom of the connecting plate 10 is provided with an inclined groove 1001.

[0022] Preferably, the connecting plate 10 is fixedly connected to the stator 13 by bolts, and the bottom of the connecting plate 10 is milled with a slanted groove 1001.

[0023] Furthermore, the force transmission component is an inclined block 9 with a beveled surface 901, and the inclined block 9 is slidably connected to the inclined groove 1001 through the beveled surface 901.

[0024] Preferably, the inclined block 9 is a right-angled triangular structure that fits perfectly with the inclined groove 1001. The inclined surface 901 slides with the inclined groove 1001. The lateral displacement is converted into the vertical upward motion of the connecting plate 10 through the transmission of the inclined surface 901, thereby pushing the stator 13 to move upward to compensate for the gap caused by the wear of the drive foot 15.

[0025] Further, see Figure 5 , Figure 6 The guide includes guide posts 12 symmetrically arranged on the bottom inner wall of the main body 1 and guide holes 11 correspondingly opened at the bottom of the connecting plate 10; the guide posts 12 slide in the copper sleeve 22 inside the guide holes 11.

[0026] Preferably, there is one set of guide posts 12 and one set of guide holes 11 on the left and right sides. The guide holes 11 are embedded with self-lubricating copper sleeves 22 to ensure that the connecting plate 10 can only move in the vertical direction, so as to ensure that the thickness of the inclined surface 901 of the horizontal movement of the inclined block 9 is completely converted into the rising height of the connecting plate 10.

[0027] Further, see Figure 5 , Figure 6 The longitudinal elastic element includes multiple sets of longitudinal telescopic rods 3 vertically distributed below the inclined block 9, longitudinal springs 2 respectively sleeved on the outer wall of the longitudinal telescopic rods 3 and in a compressed state, and support plates 5 and first mounting plates 4 respectively fixed to the top and bottom of the longitudinal telescopic rods 3; the two ends of the longitudinal springs 2 abut against the support plates 5 and the first mounting plates 4 respectively, the top of the support plates 5 abuts against the inclined block 9, and the first mounting plates 4 are fixed in the bottom groove 101.

[0028] Preferably, the longitudinal telescopic rod 3 adopts a structure of 4 sets of telescopic rods evenly and symmetrically distributed. The top of the longitudinal telescopic rod 3 contacts the inclined block 9 through the support plate 5. The bottom of the longitudinal telescopic rod 3 is fixed in the bottom groove 101 by the first mounting plate 4. 4 sets of longitudinal springs 2 with the same specifications and stiffness are sleeved on the outer wall of the longitudinal telescopic rod 3 to avoid fluctuations in preload caused by uneven force on a single spring.

[0029] Further, see Figure 4 , Figure 6 The transverse elastic element includes a transverse limiting rod 7 fixed to one side of the inclined block 9, a transverse spring 6 sleeved on the outer wall of the transverse limiting rod 7 and in a compressed state, and a limiting ring 8 sliding on the transverse limiting rod 7; the end of the transverse limiting rod 7 away from the inclined block 9 slides in the vertical groove 102.

[0030] Preferably, the transverse spring 6 is fixedly connected to the inclined block 9 by bolts through the second mounting plate 20, and the transverse spring 6 abuts against the limiting ring 8 and the second mounting plate 20 respectively. The other side of the limiting ring 8 abuts against the inner wall of the main body 1 to ensure that the transverse spring 6 always applies a horizontal thrust to the inclined block 9. It should be noted that the vertical groove 102, which runs through the side wall of the main body 1, is U-shaped. It provides a vertical guide track for the transverse limiting rod 7. The transverse spring 6, the weight of the components, and the movement requirements have been calculated. The contact surface between the limiting ring 8 and the side wall is coated with a low-friction material such as PTFE coating, so the friction can be managed. This ensures that the transverse limiting rod 7 can slide up and down along the vertical groove 102 with the longitudinal spring, while also ensuring that the thrust of the transverse spring 6 can be transmitted to the inclined block 9 in the horizontal direction, thus avoiding energy loss or jamming due to transmission deviation.

[0031] Furthermore, the angle between the oblique cut surface 901 of the oblique block 9 and the horizontal plane is set to 15°.

[0032] Preferably, the angle between the oblique cut surface 901 and the horizontal plane is set to 15°. This angle has been optimized through mechanical simulation and can achieve the maximum lifting efficiency with the minimum thrust.

[0033] Further, see Figure 1 , Figure 5 The stator 13 has piezoelectric ceramic sheets 1301 bonded to both its upper and lower surfaces. When the piezoelectric ceramic sheets 1301 are energized, the stator 13 vibrates accordingly through the inverse piezoelectric effect.

[0034] Preferably, the piezoelectric ceramic sheet 1301 is attached to the upper and lower surfaces of the "H"-shaped stator 13 beam column. One side of the piezoelectric ceramic sheet 1301 is grounded and the other side is connected to the power supply. The piezoelectric ceramic sheet 1301 is polarized in the form of d31. When the upper and lower piezoelectric ceramic sheets 1301 are excited at the same time, the stator 13 will generate high-frequency bending and torsional composite vibration. This is the prior art and will not be described in detail here.

[0035] Further, see Figure 2 , Figure 5 The bottom of the mover 16 is fixed with a grating head 18 by a fixing plate 21. A grating ruler 19 is glued to the outer side wall of the main body 1. The grating ruler 19 and the grating head 18 move closer and further away from each other as the stator 16 slides to measure speed.

[0036] Specifically, the fixed plate 21 and the mover 16 are fixedly connected by bolts. A grating ruler 19 is bonded to the outer wall of the main body 1 at the position corresponding to the grating head 18. The grating head 18 is fixed to the bottom of the fixed plate 21 by bolts. When the drive foot 15 on the stator 13 vibrates and generates elliptical trajectory motion, it drives the mover 16 by friction, which is converted into the reciprocating linear motion of the mover 16 along the guide rail 103. When there is relative motion between the grating ruler 19 fixed on the main body 1 and the grating head 18 that moves with the mover 16, the grating head 18 will continuously read the grating lines passing in front of it to measure the moving speed of the mover 16 and ensure the operating accuracy of the ultrasonic motor. The working principle of the grating head 18 and the grating ruler 19 is existing technology and will not be described in detail here.

[0037] In summary, the preload stabilizing device for a linear ultrasonic motor drive platform provided in this embodiment includes the following steps in its usage: The longitudinal spring 2 applies longitudinal preload to the mover 16 through the support plate 5, the inclined block 9, the connecting plate 10, and the stator 13, so that the mover 16 is in close contact with the drive foot 15; the transverse spring 6 is in a compressed state, providing an initial transverse thrust to the inclined block 9, ensuring that the inclined block 9 and the inclined groove 1001 of the connecting plate 10 fit together without gap. As the motor runs for a long time, the drive foot 15 wears due to friction, and a gap appears between the mover 16 and the drive foot 15. At this time, the thrust of the transverse spring 6 is released; the transverse spring 6 pushes the inclined block 9 to slide laterally along the inclined groove 1001 of the connecting plate 10. The inclined surface of the inclined block 9 converts the transverse displacement into the longitudinal lifting displacement of the connecting plate 10, which drives the stator 13 to rise until the drive foot 15 and the mover 16 are in close contact again, thus completing the automatic compensation of the wear gap. The grating ruler 19 and grating head 18 collect the motion signal of the mover 16 in real time. If the motion signal exceeds the compensation range and the preload is insufficient, the mover 16 will slip and the speed signal will deviate. The terminal will prompt to replace the drive foot 15 to avoid damage to the equipment.

[0038] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A preload stabilizing device for a linear ultrasonic motor drive platform, comprising a main body (1), wherein a mover (16) is slidably connected to the top of the main body (1), and a stator (13) is abutted against the bottom of the mover (16) by left and right symmetrical drive feet (15), characterized in that, Also includes: The transmission assembly includes a lifting member fixedly connected to the bottom of the stator (13) and a force transmission member slidably connected to the bottom of the lifting member; The lifting component is slidably connected to the main body (1) below through a guide component. The thickness of the force transmission component gradually increases. The guide component is used to limit the vertical movement of the lifting component. The compensation component includes a longitudinal elastic element disposed below the force transmission element and a transverse elastic element fixed to one side of the force transmission element; the end of the longitudinal elastic element away from the force transmission element is fixedly connected to the main body (1), and the end of the transverse elastic element away from the force transmission element is slidably connected to the main body (1). The stiffness of the transverse elastic element is less than that of the longitudinal elastic element, and the transverse elastic element is in a compressed state to always apply a transverse thrust to the force transmission element so that the force transmission element drives the lifting element to rise to compensate for the wear gap.

2. The preload stabilizing device for a linear ultrasonic motor drive platform according to claim 1, characterized in that, The lifting component includes a connecting plate (10); the bottom of the connecting plate (10) is provided with an inclined groove (1001).

3. The preload stabilizing device for a linear ultrasonic motor drive platform according to claim 2, characterized in that, The force transmission component is an inclined block (9) with a chamfered surface (901), and the inclined block (9) is slidably connected to the inclined groove (1001) through the chamfered surface (901).

4. The preload stabilizing device for a linear ultrasonic motor drive platform according to claim 3, characterized in that, The guide includes guide posts (12) symmetrically arranged on the bottom inner wall of the main body (1) and guide holes (11) corresponding to the bottom of the connecting plate (10); the guide posts (12) slide in the copper sleeve (22) inside the guide holes (11).

5. The preload stabilizing device for a linear ultrasonic motor drive platform according to claim 4, characterized in that, The longitudinal elastic element includes multiple sets of longitudinal telescopic rods (3) vertically distributed below the inclined block (9), longitudinal springs (2) respectively sleeved on the outer wall of the longitudinal telescopic rods (3) and in a compressed state, support plates (5) and first mounting plates (4) respectively fixed to the top and bottom of the longitudinal telescopic rods (3); the two ends of the longitudinal springs (2) abut against the support plates (5) and the first mounting plates (4) respectively, the support plates (5) abut against the bottom of the inclined block (9), and the first mounting plates (4) are fixed in the bottom groove (101) opened in the base of the main body (1).

6. The preload stabilizing device for a linear ultrasonic motor drive platform according to claim 5, characterized in that, The lateral elastic element includes a lateral limiting rod (7) fixed to one side of the inclined block (9), a lateral spring (6) sleeved on the outer wall of the lateral limiting rod (7) and in a compressed state, and a limiting ring (8) sliding on the lateral limiting rod (7); the end of the lateral limiting rod (7) away from the inclined block (9) slides in the vertical groove (102) opened in the side wall of the main body (1), a second mounting plate (20) is provided between the inclined block (9) and the lateral limiting rod (7), the two ends of the lateral spring (6) abut against the second mounting plate (20) and the limiting ring (8) respectively, and the side of the limiting ring (8) away from the lateral spring (6) contacts the inner side wall of the main body (1).

7. The preload stabilizing device for a linear ultrasonic motor drive platform according to claim 6, characterized in that, The angle between the oblique cut surface (901) of the oblique block (9) and the horizontal plane is set to 15°.

8. The preload stabilizing device for a linear ultrasonic motor drive platform according to claim 1, characterized in that, The stator (13) has piezoelectric ceramic sheets (1301) bonded to both the upper and lower surfaces. When the piezoelectric ceramic sheets (1301) are energized, the stator (13) vibrates accordingly through the inverse piezoelectric effect.

9. The preload stabilizing device for a linear ultrasonic motor drive platform according to claim 1, characterized in that, The bottom of the mover (16) is fixed with a grating head (18) by a fixing plate (21), and a grating ruler (19) is fixed on the outer side wall of the main body (1). The grating ruler (19) and the grating head (18) move closer and further away from each other as the mover (16) slides to measure speed.

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