A preload adjustable mechanism and piezoelectric driven micro-feeding device

Abstract

The present disclosure relates to a preload adjustable mechanism, including a machine frame and an elastic beam platform, the elastic beam platform including a platform and an elastic beam, the platform being connected to the machine frame through the elastic beam; a preload bolt, cooperating with a threaded hole provided on the machine frame, for adjusting the position of the platform, and a mounting position of a piezoelectric actuator being provided on the first end face of the platform. The present disclosure adopts a platform with a curved elastic beam structure to carry a piezoelectric actuator, which can provide a certain initial preload force before preload, making the structure compact and occupying less space, and adjusting the platform instead of the piezoelectric actuator through the preload bolt, which effectively prevents the piezoelectric actuator from being damaged by non-axial forces, torque, etc. during use.

Description

Technical Field

[0001] The present invention relates to the field of piezoelectric drive technology, and in particular to a preload adjustable mechanism and a piezoelectric drive micro-feeding device. Background Art

[0002] Piezoelectric actuators are used in precision instruments to achieve nano-level displacement drive, force drive or resonance drive, etc. In the process of using piezoelectric actuators, in order to avoid damage to the piezoelectric actuators caused by dynamic loads, it is necessary to apply a preload to the piezoelectric actuator and ensure that the piezoelectric actuator can drive its displacement output end to freely extend and contract.

[0003] At present, most of the mechanically packaged piezoelectric actuators on the market use closed packaging, placing the piezoelectric actuator in a small closed space, and the displacement output end of the piezoelectric actuator is set outside to realize the pre-tightening and displacement driving functions of the piezoelectric stack type piezoelectric driver. For example, the Chinese patent publication number CN102619821A, its main feature is to set piezoelectric ceramics, static wedges, dynamic wedges and screws in the groove of the body frame, and by screwing down the screws, the dynamic wedge pushes the static wedge downward to pre-tighten the piezoelectric ceramics, but the disadvantage is that the wedge cannot provide an initial pre-tightening force, the user cannot adjust the pre-tightening force by himself, and the downward pressure of the dynamic wedge may cause the moving direction of the static wedge to be inconsistent with the direction of the geometric axis of the piezoelectric ceramic, thereby damaging the piezoelectric ceramics. The Chinese patent publication number is CN203476938U. Its main feature is that the clamping screw is located in the transverse thread in the clamping block, and the screw head is located between the clamping block and the fixed block. It is rotated back and pressed against the fixed block, and the piezoelectric ceramic is pre-tightened by the reaction between the clamping screw and the fixed block. This invention is easy to operate, but the disadvantage is that the rotation of the clamping screw will generate a certain torque on the piezoelectric ceramic. Summary of the invention

[0004] The present disclosure provides a preload adjustable mechanism and a piezoelectric driven micro-feeding device, which can solve the technical problem that a certain initial preload cannot be provided before the piezoelectric actuator is preloaded, and the piezoelectric ceramic is easily damaged. The present disclosure provides the following technical solutions:

[0005] As one aspect of an embodiment of the present disclosure, a preload adjustable mechanism is provided, comprising:

[0006] Airframe;

[0007] An elastic beam platform, comprising a platform and an elastic beam, wherein the platform is connected to the machine body frame through the elastic beam;

[0008] The pre-tightening bolt cooperates with the threaded hole provided on the body frame and is used to adjust the position of the platform. The first end surface of the platform is provided with an installation position of the piezoelectric actuator.

[0009] Preferably, the elastic beam is in a straight line or a curved shape.

[0010] Preferably, the curved elastic beam is an S-shaped or Z-shaped curved structure.

[0011] Preferably, the two elastic beams are centrosymmetric with respect to the central axis of the platform.

[0012] Preferably, the preload adjustable mechanism further comprises a cover plate, which moves along the movement direction of the platform and is detachably connected to the platform.

[0013] Preferably, the cover plate is provided with a reamed hole, which is used in conjunction with the light hole provided on the platform; and / or, the cover plate is provided with a positioning hole, which is used to cooperate with a positioning bolt to fix the cover plate to the body frame, and the body frame is provided with a slide groove to achieve the positioning hole and the slide groove being fixed by using the positioning bolt when the cover plate moves.

[0014] Preferably, one end of the pre-tightening bolt abuts against the second end face of the platform, the second end face of the platform is opposite to the first end face of the platform, and the threaded hole is arranged at the position where the central axis of the platform and the machine frame intersect;

[0015] Alternatively, the preload adjustable mechanism also includes two wedge blocks, the wedge tips of the two wedge blocks are relatively abutted against the second end face of the platform, and the butt joint of the two wedge blocks coincides with the central axis of the platform, the preload bolts and the threaded holes are two and located on both sides of the two wedge blocks, and the preload bolts are used to adjust the two wedge blocks to achieve preload adjustment.

[0016] As another aspect of the present disclosure, a piezoelectric driven micro-feeding device is provided, comprising the above-mentioned adjustable preload mechanism and a piezoelectric actuator installed at the installation position.

[0017] Preferably, the output end of the piezoelectric actuator is connected to the flexible guide mechanism via a flexible straight circular hinge.

[0018] Preferably, the flexible guide mechanism, the flexible straight circular hinge and the body frame are integrally processed, the central axes of the flexible guide mechanism, the flexible straight circular hinge and the piezoelectric actuator are in a straight line, and the flexible guide mechanism is connected to the body frame through four edges, wherein the shape formed by the flexible guide mechanism and the four edges is a centrally symmetrical structure about the central axis of the platform.

[0019] The present invention adopts a platform with a curved elastic beam structure to carry a piezoelectric actuator, which can provide a certain initial preload force before preloading, making the structure compact and occupying less space. The platform is adjusted by preload bolts instead of piezoelectric actuators, which effectively prevents the piezoelectric actuator from being damaged by non-axial forces, torques, etc. during use. At the same time, the use of a cover plate further increases the stability of the elastic beam platform, preventing the preload bolts from being reversely micro-displaced in the threaded hole due to the reaction force of the preload force when they are adjusted in place, resulting in inaccurate preload force adjustment. When the piezoelectric driver is working, the straight circular flexible hinges and four flexible guide mechanisms symmetrical about the central axis will amplify its output motion law to a certain extent. In addition, the structurally integrated body is also convenient for installation with the base and the driven parts. The overall structure of this device is simple and highly reusable, and it is suitable for high-precision nano-drive, high-frequency resonant drive and high-precision positioning systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a preload-adjustable mechanism being a preload bolt;

[0021] Figure 2 is a schematic diagram of the preload adjustable mechanism and the cover plate;

[0022] Figure 3 is a schematic diagram of the cover;

[0023] Figure 4 It is a schematic diagram showing that the preload force adjustable mechanism is composed of a wedge block and a push bolt;

[0024] 1. Body frame, 2. Platform, 3. Elastic beam, 4. Pre-tightening bolt, 5. Piezoelectric actuator, 6. Center axis, 7. Cover plate, 8. Reamed hole, 9. Positioning hole, 10. Slide groove, 11. Wedge block, 12. Flexible straight circular hinge, 13. Flexible guide mechanism, 14. Mounting hole, 15. Light hole. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0026] Example 1

[0027] like Figure 1As shown, the present embodiment discloses a preload adjustable mechanism, comprising: a machine frame 1, which is an integrated structure, and is convenient for the installation of the machine frame 1, the base, and the driven parts. The machine frame 1 is symmetrical about the central axis 6, and two installation holes 14 are processed on the left and right sides, and the machine frame 1 is fixed to the base through the installation holes 14 by bolts. The material of the machine frame 1 is steel, such as carbon steel (65Mn) or spring steel (60Si2Mn); an elastic beam platform, comprising a platform 2 and an elastic beam 3, the platform 2 is connected to the machine frame 1 through the elastic beam 3, and the elastic beam 3 is a straight line or a curved shape. The curved elastic beam can be an S-shaped or Z-shaped curved structure, or as shown in the attached Figure 1 Other elastic structures related to the structure shown in the figure, one end of the elastic beam 3 is connected to the platform 2, and the other end of the elastic beam 3 is connected to the body frame 1. The connection point between the elastic beam 3 and the platform 2 and the connection point between the elastic beam 3 and the body frame 1 may be in a straight line or not in a straight line, so the deformation rebound force generated by the elastic beam 3 acts on the platform 2, giving the platform 2 a certain amount of initial pre-tightening force; the pre-tightening bolt 4 cooperates with the threaded hole set at the bottom of the body frame 1, and the position of the platform 2 is adjusted by rotating the pre-tightening bolt 4. The first end surface of the platform 2 is provided with an installation position of the piezoelectric actuator 5. Therefore, the pre-tightening bolt 4 adds an adjustable pre-tightening force on the basis of the initial pre-tightening force, directly acts on the platform 2, and indirectly adjusts the position of the piezoelectric actuator 5. At this time, when the pre-tightening force is adjusted by the pre-tightening bolt 4, the piezoelectric actuator 5 is free from the shear force or torsional force of the pre-tightening bolt 4.

[0028] As a preferred embodiment, the two elastic beams 3 are centrosymmetric with respect to the central axis 6 of the platform 2 .

[0029] As a preferred embodiment, Figure 2-3 As shown, the preload adjustable mechanism also includes a cover plate 7, which moves along the movement direction of the platform 2 and is detachably connected to the platform 2. After the preload is adjusted by the preload bolts 4, the cover plate 7 is used to increase the stability of the elastic beam platform.

[0030] As a preferred embodiment, the cover plate 7 is provided with a reaming hole 8, and the reaming hole 8 is used in conjunction with the light hole 15 provided on the platform 2;

[0031] The cover plate 7 is provided with a positioning hole 9, and the positioning hole 9 is used to cooperate with a positioning bolt to fix the cover plate 7 on the body frame 1. The body frame 1 is provided with a slide groove 10 to achieve the positioning hole 9 and the slide groove 10 being fixed by the positioning bolt when the cover plate 7 moves.

[0032] In this embodiment, the reaming hole 8 of the cover plate 7 corresponds to the light hole 15 of the platform 2, and the reaming hole is connected with bolts. The two left and right positioning holes 9 at the lower part of the cover plate 7 correspond to the two slide grooves 10 on the body frame 1, and are connected with ordinary bolts. While the pre-tightening bolt 4 adjusts the pre-tightening force of the piezoelectric actuator 5, the cover plate 7 also increases the stability of the elastic beam platform. After the pre-tightening bolt 4 is adjusted, the cover plate 7 is fixed to the platform 2, and the cover plate 7 is fixed to the body frame 1. At this time, the platform 2 cannot move up and down.

[0033] As a preferred embodiment, one end of the pre-tightening bolt 4 abuts against the second end face of the platform 2, the second end face of the platform 2 is opposite to the first end face of the platform 2, and the threaded hole is arranged at the intersection of the central axis 6 of the platform 2 and the body frame 1.

[0034] As another preferred embodiment, Figure 4 As shown, the preload adjustable mechanism also includes two wedge blocks 11, the butt joint of the two wedge blocks 11 abuts against the second end face of the platform 2, and the central axis of the two wedge blocks 11 coincides with the central axis 6 of the platform 2, the preload bolt 4 and the threaded hole are two and located on both sides of the two wedge blocks 11, and the preload bolt 4 is used to adjust the two wedge blocks 11 to achieve preload adjustment.

[0035] Example 2

[0036] like Figure 2 As shown in or 4, a piezoelectric driven micro-feeding device includes the preload adjustable mechanism in Example 1 and a piezoelectric actuator 5 installed at the installation position.

[0037] As a preferred embodiment, the output end of the piezoelectric actuator 5 is connected to the flexible guiding mechanism 13 through a flexible straight circular hinge 12. In this embodiment, the output end of the piezoelectric actuator 5 abuts the flexible straight circular hinge 12, and the opposite end of the output end of the piezoelectric actuator 5 abuts the first end surface of the platform 2; the flexible straight circular hinge 12 is connected to the flexible guiding mechanism 13; the driven part can be properly installed at the flexible guiding mechanism 13, and when a driving voltage is applied to the piezoelectric actuator 5, according to its inverse piezoelectric effect, the piezoelectric actuator 5 will stretch axially, and transmit the displacement through the flexible straight circular hinge and the flexible guiding mechanism 13, thereby realizing micro-feed of the driven part along the axial direction.

[0038] As a preferred embodiment, the flexible guide mechanism, the flexible straight circular hinge and the body frame are integrally processed, the flexible guide mechanism 13, the flexible straight circular hinge 12 and the central axis 6 of the piezoelectric actuator 5 are on a straight line, and the flexible guide mechanism 13 is connected to the body frame 1 through four edges, wherein the shape formed by the flexible guide mechanism 13 and the four edges is a centrally symmetrical structure about the central axis 6 of the platform.

[0039] Although embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present disclosure, and the scope of the present disclosure is defined by the appended claims and their equivalents.

Claims

1. A preload adjustable mechanism, characterized in that: include: Airframe; An elastic beam platform, comprising a platform and an elastic beam, wherein the platform is connected to the machine frame through the elastic beam; the two elastic beams are centrally symmetrical with the central axis of the platform; A pre-tightening bolt, which cooperates with a threaded hole provided on the body frame and is used to adjust the position of the platform, wherein a mounting position of the piezoelectric actuator is provided on the first end surface of the platform; The preload adjustable mechanism further comprises a cover plate, which moves along the movement direction of the platform and is detachably connected to the platform; The cover plate is provided with a positioning hole, and the positioning hole is used to cooperate with a positioning bolt to fix the cover plate on the body frame. The body frame is provided with a slide groove to achieve the positioning hole and the slide groove being fixed by the positioning bolt when the cover plate moves.

2. The preload adjustable mechanism according to claim 1, characterized in that: The elastic beam is in a straight line or curved shape.

3. The preload adjustable mechanism according to claim 1, characterized in that: The elastic beam is S-shaped.

4. The preload adjustable mechanism according to claim 1 or 2, characterized in that: The elastic beam is a Z-shaped bending structure.

5. The preload adjustable mechanism according to claim 1 or 2, characterized in that: One end of the pre-tightening bolt abuts against the second end surface of the platform, the second end surface of the platform is opposite to the first end surface of the platform, and the threaded hole is arranged at the intersection of the central axis of the platform and the body frame.

6. The preload adjustable mechanism according to claim 1, characterized in that: The cover plate is provided with a reaming hole, and the reaming hole is used in conjunction with the light hole provided on the platform.

7. The preload adjustable mechanism according to claim 1 or 2, characterized in that: The adjustable preload force mechanism also includes two wedge blocks, the wedge tips of the two wedge blocks are relatively abutted against the second end face of the platform, and the butt joint of the two wedge blocks coincides with the central axis of the platform. There are two preload bolts and threaded holes and they are located on both sides of the two wedge blocks. The preload bolts are used to adjust the two wedge blocks to achieve preload force adjustment.

8. A piezoelectric driven micro-feeding device, characterized in that: It comprises a preload adjustable mechanism as claimed in any one of claims 1 to 7 and a piezoelectric actuator installed at the installation position.

9. The piezoelectric driven micro-feeding device according to claim 8, characterized in that: The output end of the piezoelectric actuator is connected to the flexible guide mechanism through a flexible straight circular hinge.

10. The piezoelectric driven micro-feeding device according to claim 9, characterized in that: The flexible guide mechanism, the flexible straight circular hinge and the body frame are integrally processed, the central axes of the flexible guide mechanism, the flexible straight circular hinge and the piezoelectric actuator are in a straight line, and the flexible guide mechanism is connected to the body frame through four sides, wherein the shape formed by the flexible guide mechanism and the four sides is a centrally symmetrical structure with respect to the central axis of the platform.

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