阅读说明：本技术 摩擦驱动致动器及其缓冲支架 (Friction drive actuator and buffer bracket thereof ) 是由 陈皇翰 萧士元 童景隆 于 2019-01-21 设计创作，主要内容包括：本发明公开一种摩擦驱动致动器及其缓冲支架。缓冲支架为一体成形的单件式构造、且包括用以安装于压电组件的基部、自基部延伸的第一弹性臂、与第一弹性臂呈平行地间隔设置的第二弹性臂以及连接第一弹性臂与第二弹性臂的连接臂。第二弹性臂的抵接端部与基部之间的距离大于第一弹性臂的第一自由端部与基部之间的距离,第二弹性臂的第二自由端部邻近但未接触于所述基部。连接臂连接于邻近第一自由端部的第一弹性臂部位以及连接于邻近第二自由端部的第二弹性臂部位。据此,摩擦驱动致动器通过缓冲支架的结构设计以具备有多个支撑点,来提供适合摩擦驱动致动器的缓冲效果,进而有效地提升摩擦驱动致动器的效能。(The invention discloses a friction drive actuator and a buffer bracket thereof. The buffer support is of an integrally formed one-piece structure and comprises a base part used for being installed on the piezoelectric component, a first elastic arm extending from the base part, a second elastic arm arranged in parallel with the first elastic arm at an interval and a connecting arm connecting the first elastic arm and the second elastic arm. The distance between the abutting end of the second resilient arm and the base is greater than the distance between the first free end of the first resilient arm and the base, the second free end of the second resilient arm being adjacent to but not in contact with the base. The connecting arm is connected to a first resilient arm portion adjacent the first free end portion and to a second resilient arm portion adjacent the second free end portion. Therefore, the friction drive actuator is provided with a plurality of supporting points through the structural design of the buffer bracket, so that the buffer effect suitable for the friction drive actuator is provided, and the efficiency of the friction drive actuator is further effectively improved.)

1. A friction drive actuator, comprising:

a driver module, comprising:

the shell comprises a first surface and a second surface which are positioned on two opposite sides, a containing groove is concavely formed on the first surface of the shell, and the containing groove comprises a first inner wall and a second inner wall which are opposite to each other;

the piezoelectric component is positioned in the accommodating groove and is arranged on the first inner wall, and the piezoelectric component can deform along an operation direction;

a buffer bracket, which is an integrally formed one-piece structure, the buffer bracket is located in the accommodating groove and comprises:

a base mounted to the piezoelectric assembly and facing the second inner wall;

a first elastic arm formed by extending from the base portion toward the second inner wall along the operating direction, and a first free end portion of the first elastic arm not contacting the second inner wall;

a connecting arm including a first end portion and a second end portion at opposite ends, the first end portion being connected to the first resilient arm portion adjacent the first free end portion; and

a second elastic arm, spaced from the first elastic arm, and including an abutting end portion and a second free end portion, wherein the abutting end portion abuts against the second inner wall, and the second free end portion is adjacent to but not in contact with the base portion; wherein the second end of the connecting arm is connected to the second resilient arm portion adjacent the second free end; and

the friction pad is arranged on the first elastic arm and is separated from the base part by a certain distance, the friction pad is positioned on an extending path of the connecting arm, and at least part of the friction pad protrudes out of the accommodating groove; and

the driven piece comprises a smooth surface parallel to the operation direction, and the friction pad of the driving module is pressed against the smooth surface of the driven piece.

2. A friction drive actuator as defined in claim 1 wherein said first and second ends of said connecting arm are perpendicularly connected to said first and second resilient arms, respectively.

3. The friction drive actuator of claim 1, wherein the thickness of the first resilient arm, the thickness of the second resilient arm, and the thickness of the connecting arm are each between 0.2 mm and 0.3 mm.

4. The friction drive actuator of claim 1, wherein said damping bracket includes a first block portion connected to said first resilient arm, said first block portion being positioned between said base portion and said connecting arm, and said first block portion being spaced from said base portion and said connecting arm, respectively.

5. The friction drive actuator of claim 4, wherein the length of the first resilient arm portion connected to the first block portion is 35% to 45% of the total length of the first resilient arm; the first block-shaped part is projected towards the connecting arm along the operation direction to form a projection area, and 35% -45% of the connecting arm part is covered by the first block-shaped part.

6. The friction drive actuator of claim 4, wherein the damping mount includes a second block portion, and wherein the second block portion is connected to the abutting end of the second spring arm, the second block portion being pressed against the second inner wall.

7. The friction drive actuator of claim 6, wherein the length of the second resilient arm portion connected to the second block portion is 15% to 25% of the total length of the second resilient arm; the second block part is projected towards the orthographic projection of the connecting arm along the operation direction to form a projection area, and the projection area covers 55% -65% of the connecting arm.

8. The friction drive actuator according to claim 1, wherein the housing is formed with a fitting groove recessed in the second surface, and a groove bottom of the fitting groove communicates with the receiving groove;

the driving module further comprises:

a cover body mounted in the tabling groove; and

and the screw is arranged in the cover body in a threaded manner, and part of the screw is positioned in the accommodating groove and is propped against the second free end part of the second elastic arm.

9. A cushion bracket for a friction drive actuator, the cushion bracket being of one-piece construction, the cushion bracket comprising:

a base for mounting to a piezoelectric element;

a first resilient arm formed extending from the base and including a first free end;

a connecting arm including a first end portion and a second end portion at opposite ends, the first end portion being connected to the first resilient arm portion adjacent the first free end portion; and

a second resilient arm spaced parallel to the first resilient arm and including an abutting end portion and a second free end portion, the abutting end portion being spaced from the base portion by a distance greater than the first free end portion, the second free end portion being adjacent to but not contacting the base portion; wherein the second end of the connecting arm is connected to the second resilient arm portion adjacent the second free end.

10. A damping bracket for a friction drive actuator according to claim 9 wherein the thickness of the first resilient arm, the thickness of the second resilient arm and the thickness of the connecting arm are each between 0.2 mm and 0.3 mm; the buffer bracket comprises a first block part connected with the first elastic arm, the first block part is positioned between the base part and the connecting arm, and the first block part and the base part and the connecting arm are respectively arranged at intervals; the buffer bracket comprises a second block part, and the second block part is connected to the abutting end part of the second elastic arm.

Technical Field

The present disclosure relates to actuators, and particularly to a friction drive actuator and a damping mount thereof.

Background

In the conventional friction driving actuator, the flexible sheet is usually engaged with the system spring between the piezoelectric element and the driven element. However, the structure of the standard spring is a general type and is not designed for the friction drive actuator, so that there is room for further improvement in the performance of the friction drive actuator. Furthermore, the flexible sheet and the standard spring have production tolerance, and the matching of the flexible sheet and the standard spring also has assembly tolerance, and the accumulation of the tolerance also has a space for further improvement.

The present inventors have considered that the above-mentioned drawbacks can be improved, and have made intensive studies and use of scientific principles, and finally have proposed the present invention which is designed reasonably and effectively to improve the above-mentioned drawbacks.

Disclosure of Invention

Embodiments of the present invention provide a friction drive actuator and a buffer bracket thereof, which are used to effectively overcome the possible defects of the conventional friction drive actuator.

The embodiment of the invention discloses a friction drive actuator, which comprises: a driver module, comprising: the shell comprises a first surface and a second surface which are positioned on two opposite sides, a containing groove is concavely formed on the first surface of the shell, and the containing groove comprises a first inner wall and a second inner wall which are opposite to each other; the piezoelectric component is positioned in the accommodating groove and is arranged on the first inner wall, and the piezoelectric component can deform along an operation direction; a buffer bracket, which is an integrally formed one-piece structure, the buffer bracket is located in the accommodating groove and comprises: a base mounted to the piezoelectric assembly and facing the second inner wall; a first elastic arm formed by extending from the base portion toward the second inner wall along the operating direction, and a first free end portion of the first elastic arm not contacting the second inner wall; a connecting arm including a first end portion and a second end portion at opposite ends, the first end portion being connected to the first resilient arm portion adjacent the first free end portion; a second elastic arm, spaced from the first elastic arm, including an abutting end and a second free end, the abutting end abutting against the second inner wall, the second free end being adjacent to but not contacting the base; wherein the second end of the connecting arm is connected to the second resilient arm portion adjacent the second free end; the friction pad is arranged on the first elastic arm and is separated from the base part by a certain distance, the friction pad is positioned on an extending path of the connecting arm, and at least part of the friction pad protrudes out of the accommodating groove; the driven piece comprises a smooth surface parallel to the operation direction, and the driving module presses the smooth surface of the driven piece by the friction pad.

Preferably, the first end portion and the second end portion of the connecting arm are perpendicularly connected to the first elastic arm and the second elastic arm, respectively.

Preferably, the thickness of the first resilient arm, the thickness of the second resilient arm, and the thickness of the connecting arm are each between 0.2 millimeters (mm) and 0.3 mm.

Preferably, the buffer bracket includes a first block portion connected to the first elastic arm, the first block portion is located between the base portion and the connecting arm, and the first block portion is spaced from the base portion and the connecting arm, respectively.

Preferably, the length of the first elastic arm part connected with the first block part accounts for 35 to 45 percent of the total length of the first elastic arm; the first block-shaped part is projected towards the connecting arm along the operation direction to form a projection area, and 35% -45% of the connecting arm part is covered by the first block-shaped part.

Preferably, the buffer bracket comprises a second block part, the second block part is connected to the abutting end part of the second elastic arm, and the second block part is pressed against the second inner wall.

Preferably, the length of the second elastic arm part connected with the second block part accounts for 15% -25% of the total length of the second elastic arm; the second block part is projected towards the orthographic projection of the connecting arm along the operation direction to form a projection area, and the projection area covers 55% -65% of the connecting arm.

Preferably, the housing is concavely provided with a fitting groove on the second surface, and the bottom of the fitting groove is communicated with the accommodating groove; the driving module further comprises: a cover body mounted in the tabling groove; and the screw is arranged in the cover body in a threaded manner, and part of the screw is positioned in the accommodating groove and is propped against the second free end part of the second elastic arm.

The embodiment of the invention also discloses a buffer bracket of a friction drive actuator, which is of an integrally formed one-piece structure and comprises: a base for mounting to a piezoelectric element; a first resilient arm formed extending from the base and including a first free end; a connecting arm including a first end portion and a second end portion at opposite ends, the first end portion being connected to the first resilient arm portion adjacent the first free end portion; a second resilient arm spaced parallel to the first resilient arm and including an abutting end portion and a second free end portion, the abutting end portion being spaced from the base portion by a distance greater than the first free end portion, the second free end portion being adjacent to but not in contact with the base portion; wherein the second end of the connecting arm is connected to the second resilient arm portion adjacent the second free end.

Preferably, the thickness of the first elastic arm, the thickness of the second elastic arm and the thickness of the connecting arm are respectively between 0.2 mm and 0.3 mm; the buffer bracket comprises a first block part connected with the first elastic arm, the first block part is positioned between the base part and the connecting arm, and the first block part and the base part and the connecting arm are respectively arranged at intervals; the buffer bracket comprises a second block part, and the second block part is connected with the abutting end part of the second elastic arm.

In summary, the friction driving actuator disclosed in the embodiments of the present invention has a plurality of supporting points (e.g., a joint between the base and the piezoelectric element, a joint between the second elastic arm and the second inner wall, a joint between the connecting arm and the first elastic arm and the second elastic arm, and a joint between the first elastic arm and the base) through the structural design of the buffering bracket, so that the buffering bracket can provide a buffering effect suitable for the friction driving actuator, thereby effectively improving the performance of the friction driving actuator.

Furthermore, the buffer bracket disclosed in the embodiment of the present invention is a one-piece structure, so that the buffer bracket only has manufacturing tolerance (the manufacturing tolerance is smaller than the assembly tolerance), and the accumulation of the manufacturing tolerance and the assembly tolerance is not generated, thereby enhancing the performance of the friction drive actuator.

For a better understanding of the nature and technical content of the present invention, reference should be made to the following detailed description of the invention and the accompanying drawings, which are provided for illustration purposes only and are not intended to limit the scope of the invention in any way.

Drawings

Fig. 1 is a perspective view of a friction drive actuator according to an embodiment of the present invention.

Fig. 2 is an exploded view of fig. 1.

Fig. 3 is an exploded view of fig. 1 from another perspective.

Fig. 4 is a schematic cross-sectional view of fig. 1 along the sectional line IV-IV.

Fig. 5 is an enlarged schematic view of a portion V in fig. 4.

Fig. 6 is a schematic perspective view of a cushion bracket and a friction pad according to an embodiment of the invention.

Fig. 7 is a perspective view of fig. 6 from another angle.

Fig. 8 is a schematic plan view of a buffer bracket according to an embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view of another aspect of the friction drive actuator of the present invention.

Detailed Description

Please refer to fig. 1 to 9, which are exemplary embodiments of the present invention, and it should be noted that, in the exemplary embodiments, related numbers and shapes mentioned in the accompanying drawings are only used for describing the embodiments of the present invention in detail, so as to facilitate the understanding of the contents of the present invention, and not for limiting the scope of the present invention.

As shown in fig. 1, the present embodiment discloses a friction driving actuator 100, which is suitable for a positioning mechanism, a scanning device, or a microscope, etc. with high precision requirement, but the invention is not limited thereto. The friction driving actuator 100 includes a driving module 1 and a driven module 2 capable of moving relative to the driving module 1. It should be noted that, in the present embodiment, only some components in the driving module 1 and the driven module 2 are described in each pair; that is, the driving module 1 and the driven module 2 may each include components other than the following components.

As shown in fig. 2 and 3, the driven module 2 includes a base 21 and a driven member 22 mounted on the base 21. The driven member 22 includes a smooth surface 221 facing the driving module 1, and the driven member 22 is illustrated as a rectangular stainless steel strip in this embodiment, but the invention is not limited thereto.

As shown in fig. 2 and 3, the driving module 1 includes a housing 11, a cover 12 detachably disposed on the housing 11, a screw 13 screwed into the cover 12, a piezoelectric element 14 and a buffer bracket 15 mounted in the housing 11, and a friction pad 16 disposed on the buffer bracket 15.

It should be noted that the buffer bracket 15 is described in the embodiment with the above components, but the invention is not limited thereto. For example, in other embodiments not shown in the present disclosure, the buffer bracket 15 may be used alone (for example, sold) or used in combination with other components. The respective component configurations of the drive module 1 of the present embodiment and the connection relationship therebetween will be described below.

As shown in fig. 4 and 5, the housing 11 includes a first surface 111 and a second surface 112 on opposite sides. The housing 11 is recessed on the first surface 111 to form a receiving groove 113 for receiving the piezoelectric element 14 and the buffer bracket 15, and the receiving groove 113 includes a first inner wall 1131 and a second inner wall 1132 facing each other. In the present embodiment, the receiving groove 113 is substantially rectangular, and the first inner wall 1131 and the second inner wall 1132 are parallel to each other and their positions respectively correspond to two short edges of the rectangular receiving groove 113, but the invention is not limited thereto.

Furthermore, the housing 11 is formed with a fitting groove 114 on the second surface 112 in a concave manner, and a groove bottom (a part) of the fitting groove 114 is communicated with the accommodating groove 113; in other words, the first inner wall 1131 and the second inner wall 1132 of the receiving groove 113 are vertically connected to the bottom of the fitting groove 114. In the embodiment, the size of the fitting groove 114 is larger than the receiving groove 113, and the outer shape of the fitting groove 114 corresponds to the outer shape of the cover 12, but the invention is not limited thereto.

As shown in fig. 2 and 4, the cover 12 is detachably mounted in the fitting groove 114 of the housing 11, and the outer surface of the cover 12 is preferably disposed coplanar with the second surface 112 of the housing 11, and the cover 12 closes the side of the accommodating groove 113 away from the first surface 111; that is, the inner surface of the lid 12 corresponds to the bottom of the accommodation groove 113. The screw 13 is screwed into the cover 12, and a part of the screw 13 is located in the receiving groove 113 of the housing 11. In the present embodiment, the screw 13 is preferably a set screw, and the screw 13 is screwed from the outer surface of the cover 12 to the inner surface thereof, but the present invention is not limited thereto.

As shown in fig. 3 and 4, the piezoelectric element 14 is located in the receiving groove 113 of the housing 11 and is mounted on the first inner wall 1131, and the piezoelectric element 14 is disposed at a distance from the inner surface of the cover 12. Wherein the piezoelectric element 14 is deformable in an operating direction D; that is, the piezoelectric element 14 can be deformed to expand or contract in the operating direction D under the influence of the voltage signal.

Furthermore, the operating direction D is perpendicular to the first inner wall 1131 (or the second inner wall 1132) in this embodiment, and the operating direction D is parallel to the smooth surface 221 of the driven member 22. In addition, the operation direction D can be further regarded as an operation plane D in the present embodiment; that is, the smooth surface 221 of the driven member 22 is parallel to the operation plane D, but the invention is not limited thereto.

As shown in fig. 5 to 8, the buffer bracket 15 is a one-piece structure, and the buffer bracket 15 is made of metal, carbon fiber, plastic, or other elastic materials. The buffer bracket 15 is located in the receiving groove 113 of the housing 11, the buffer bracket 15 is mounted on the piezoelectric element 14 and abuts against the second inner wall 1132 and the screw 13 located in the receiving groove 113, and the buffer bracket 15 is further spaced apart from the inner surface of the cover 12.

Further, as shown in fig. 5, the buffer bracket 15 includes a base 151, a first elastic arm 152 connected to the base 151, a second elastic arm 153 spaced (parallel) from the first elastic arm 152, a connecting arm 154 connecting the first elastic arm 152 and the second elastic arm 153, a first block 155 connected to the first elastic arm 152, and a second block 156 connected to the second elastic arm 153.

As shown in fig. 5 to 8, the base 151 is mounted on the piezoelectric element 14 and faces the second inner wall 1132; in the present embodiment, the base 151 is a substantially rectangular block and is fixed to the surface of the piezoelectric element 14 away from the first inner wall 1131 (e.g., the left surface of the piezoelectric element 14 in fig. 5), and the outer edge of the base 151 is preferably aligned with the outer edge of the piezoelectric element 14, but the invention is not limited thereto.

The first elastic arm 152, the second elastic arm 153 and the connecting arm 154 are all in the shape of a sheet in this embodiment, and the first elastic arm 152 and the second elastic arm 153 are preferably parallel to the operating direction D, while the connecting arm 154 is perpendicular to the operating direction D. The thickness T152 of the first elastic arm 152, the thickness T153 of the second elastic arm 153, and the thickness T154 of the connecting arm 154 are each between 0.2 millimeters (mm) and 0.3 mm.

In addition, the first elastic arm 152 extends from the base 151 toward the second inner wall 1132 along the operation direction D, and a first free end portion 1521 of the first elastic arm 152 is not in contact with the second inner wall 1132, in the present embodiment, the first elastic arm 152 is perpendicularly connected to one end of the base 151 to form an L-shaped structure, and the first elastic arm 152 is located away from the cover 12 and aligned with the first surface 111 of the housing 11.

The second elastic arm 153 includes an abutting end portion 1531 and a second free end portion 1532 located at opposite sides thereof, the abutting end portion 1531 abuts against the second inner wall 1132, and the second free end portion 1532 is adjacent to but not in contact with the base portion 151. That is, the distance between the abutting end 1531 and the base 151 is greater than the distance between the first free end 1521 and the base 151. Furthermore, the second elastic arm 153 is adjacent to the inner surface of the cover 12, and the screw 13 located in the accommodating groove 113 partially abuts against the second free end portion 1532 of the second elastic arm 153.

The connecting arm 154 includes a first end 1541 and a second end 1542 at opposite ends, the first end 1541 is connected to the first elastic arm 152 adjacent to the first free end 1521, and the second end 1542 is connected to the second elastic arm 153 adjacent to the second free end 1532. In the present embodiment, the first end 1541 and the second end 1542 of the connecting arm 154 are respectively and vertically connected to the first elastic arm 152 and the second elastic arm 153, but the invention is not limited thereto. For example, the shape of the connecting arm 154 can also be adjusted or changed according to design requirements, such as: the connecting arm 154 may be a continuously curved resilient structure.

The first block 155 is connected to an inner surface of the first elastic arm 152, and the first block 155 faces the second free end 1532 of the second elastic arm 153. In other words, the first block portion 155 is located between the base portion 151 and the connecting arm 154, and the first block portion 155 is spaced apart from the base portion 151 and the connecting arm 154.

In more detail, the first elastic arm 152 can be reinforced in structural strength by the first block portion 155, and the structure of the first block portion 155 can be adjusted and changed according to actual requirements, in the present embodiment, the first block portion 155 is a substantially rectangular block body, and is matched with other portions of the buffer bracket 15 in a specific relationship as described below, so that the buffer bracket 15 can have a preferable buffer effect, but the present invention is not limited thereto, a length L155 of the first elastic arm 152 portion connected to the first block portion 155 is 35% to 45% of a total length L152 of the first elastic arm 152, and a projection area formed by the first block portion 155 projecting toward the connecting arm 154 in the operation direction D is preferably covered with 35% to 45% of the connecting arm 154 portion.

The second block 156 is connected to (an inner surface of) the abutting end 1531 of the second elastic arm 153, and the second block 156 is pressed against the second inner wall 1132, in the present embodiment, the second elastic arm 153 is vertically connected to one end of the second block 156 to form an L-shaped structure together, in other words, an inner corner of the L-shaped structure formed by the second elastic arm 153 and the second block 156 faces obliquely an inner corner of the L-shaped structure formed by the first elastic arm 152 and the base 151.

More specifically, the second resilient arm 153 is reinforced in structural strength by the second block 156, and the structure of the second block 156 can be adjusted and varied according to actual requirements, in the present embodiment, the second block 156 is a substantially rectangular block and is disposed at other portions of the buffer bracket 15 in a specific relationship as described below, so that the buffer bracket 15 can have a preferable buffer effect, but the present invention is not limited thereto, a length L156 of the second resilient arm 153 connected to the second block 156 occupies 15% to 25% of a total length L153 of the second resilient arm 153, and a projection area formed by the second block 156 projecting in the operating direction D toward the connecting arm 154 preferably covers 55% to 65% of the connecting arm 154.

It should be noted that, in the buffering bracket 15 shown in fig. 5 of the present embodiment, it is described as including the first block portion 155 and the second block portion 156, but the invention is not limited thereto. For example, in other embodiments of the present invention, at least one of the first block 155 and the second block 156 may be omitted from the buffer bracket 15 according to design requirements (see fig. 9).

As shown in fig. 4 and 5, the friction pad 16 is mounted on (an outer surface of) the first elastic arm 152 and is spaced apart from the base 151 in the operating direction D. The friction pad 16 is located on the extending path of the connecting arm 154, and at least a portion of the friction pad 16 protrudes out of the accommodating groove 113 (or the first surface 111), so that the driving module 1 can press the friction pad 16 against the smooth surface 221 of the driven member 22.

In this embodiment, the area along which the friction pad 16 is orthographically projected toward the second elastic arm 153 covers the entire connecting arm 154 and a portion of the first block 155, so that the friction pad 16 can be effectively supported by the buffer bracket 15. Furthermore, the friction pad 16 is rectangular and made of mainly alumina, and the corners of the friction pad 16 adjacent to the driven member 22 are chamfered in this embodiment, so as to avoid scratching the smooth surface 221 of the driven member 22.

It should be noted that the buffer bracket 15 and the friction pad 16 are two independent structures in this embodiment, but the invention is not limited thereto. For example, in other embodiments not shown in the present invention, the buffering bracket 15 and the friction pad 16 may be integrally formed as a single piece, the buffering bracket 15 and the friction pad 16 are made of metal, and the driven member 22 is made of alumina.

[ technical effects of embodiments of the present invention ]

In summary, the friction driving actuator disclosed in the embodiments of the present invention has a plurality of supporting points (e.g., a joint between the base and the piezoelectric element, a joint between the second elastic arm and the second inner wall, a joint between the connecting arm and the first elastic arm and the second elastic arm, and a joint between the first elastic arm and the base) through the structural design of the buffering bracket, so that the buffering bracket can provide a buffering effect suitable for the friction driving actuator, thereby effectively improving the performance of the friction driving actuator.

Furthermore, the buffer bracket disclosed in the embodiment of the present invention is a one-piece structure, so that the buffer bracket only has manufacturing tolerance (the manufacturing tolerance is smaller than the assembly tolerance), and the accumulation of the manufacturing tolerance and the assembly tolerance is not generated, thereby enhancing the performance of the friction drive actuator.

In addition, the buffering bracket disclosed in the embodiment of the invention can be additionally provided with the first block-shaped part and the second block-shaped part on the first elastic arm and the second elastic arm so as to meet different buffering requirements. In the present embodiment, the first block portion and the second block portion further provide a preferable configuration manner compared with other portions of the buffer bracket, so that the buffer bracket can have a preferable buffering effect.

In addition, the friction drive actuator disclosed in the embodiment of the invention is detachably mounted in the housing through the cover, so that the maintenance and the repair of the internal components of the drive module are facilitated.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the scope of the present invention, which is defined by the appended claims.