Electric actuator

Abstract

To provide an electric actuator capable of simplifying a structure of the electric actuator by integrating a sliding seat and a nut member of a sliding unit, facilitating assembly to reduce combination tolerance, and improving operation accuracy of the electric actuator.SOLUTION: The electric actuator (50) includes a cylindrical housing (52), a slide unit (54), and a screw shaft (56). At least one guide groove extending in the longitudinal direction is provided on a hole wall of the cylindrical housing (52). The sliding unit (54) includes a rotation-limiting member (72), a nut member (70) and an output shaft, the rotation-limiting member (72) has at least one guide block fitted to a first end of the nut member (70) and used for fitting to a guide groove of the cylindrical housing (52), and one end of the output shaft (74) is fitted to a second end of the nut member (70). The screw shaft 56 is connected to the nut member 70 in a relatively movable manner.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an electric actuator, and more particularly to a sliding unit applied to an electric actuator. [Background technology]

[0002] Electric actuators or sliding devices, widely used in industrial processing tables, are driven by a motor and transmit power via a screw shaft, allowing the load end to move linearly. Figures 1-2 show a general-purpose electric actuator comprising a cylindrical housing 10, a sliding unit 12 inserted into the cylindrical housing 10, and a screw shaft 14. Two opposing guide grooves 16 are provided on the inner wall of the cylindrical housing 10. The sliding unit 12 comprises a sliding seat 18, a nut member 20, and an output shaft 22. The sliding seat 18 has a first end 24 and a second end 26 separated from each other in the longitudinal direction, and a through-hole 28 extending therethrough in the longitudinal direction. The nut member 20 is fixed to the first end 24 of the sliding seat 18 using a bolt 30, and one end of the output shaft 22 is connected to the second end 26 of the sliding seat 18, allowing the sliding seat 18, the nut member 20, and the output shaft 22 to move longitudinally within the cylindrical housing 10. The inner wall of the nut member 20 has a helical inner groove 32. The outer segment of the screw shaft 14 passes through the interior of the nut member 20 and the through-hole 28 of the sliding seat 18, and a helical outer edge groove 34 is formed on the outer edge of the screw shaft 14. A ball 36 is disposed between the outer edge groove 34 and the inner groove 32 of the nut member, so that when the screw shaft 14 rotates, the nut member 20 is driven to move in the vertical direction relative to the screw shaft 14. In this embodiment, the inner segment of the screw shaft 14 is fitted into a mounting seat 38, and the mounting seat 38 is fitted to a motor (not shown). The screw shaft 14 is then connected to the rotating shaft (not shown) of the motor, so that the screw shaft 14 can be driven by the motor. Furthermore, two opposing guide blocks 40 are provided on the outside of the sliding seat 18, and the guide blocks 40 are respectively positioned inside the two guide grooves 16 of the cylindrical housing 10, thereby preventing the sliding seat 18 and the output shaft 22 from rotating when moving within the cylindrical housing 10.

[0003] However, the number of parts in the sliding unit 12 is too large, which not only makes assembly time more time-consuming, but also makes it easy for tolerances to occur when combining multiple parts, reducing the accuracy of the linear motion of the sliding unit 12 and adversely affecting the operating accuracy of the electric actuator. Furthermore, the two guide blocks 40 are connected to the sliding seat 18 using bolts 42, which makes the structure of the sliding unit 12 complicated. Furthermore, deviations are easily caused by tightening the bolts, which is unfavorable for properly positioning the guide blocks 40 in the guide groove 16 and can also cause combination tolerances, which can cause the sliding seat 18 to move or vibrate unevenly, potentially affecting the stability of the linear motion of the sliding unit 12. Summary of the Invention [Problem to be solved by the invention]

[0004] The main object of the present invention is not only to provide an electric actuator that simplifies the structure of the electric actuator by integrating the sliding seat and nut member of the sliding unit, thereby facilitating assembly and reducing assembly tolerances, thereby improving the operating accuracy of the electric actuator, but also to design a rotation limiting member for the electric actuator that effectively prevents rotation of the sliding unit during movement, making it easy to assemble the rotation limiting member and cylindrical housing. [Means for solving the problem]

[0005] According to one embodiment of the present invention, the electric actuator includes a cylindrical housing, a sliding unit, and a screw shaft. The cylindrical housing has an interior with a longitudinally extending receiving hole, and the receiving hole has at least one longitudinally extending guide groove in its wall. The sliding unit includes a rotation limiting member, a nut member, and an output shaft. The nut member has an interior with a longitudinally extending through-hole, and the nut member further has first and second ends separated from each other in the longitudinal direction. The rotation limiting member has an annular body fitted to the first end of the nut member, the interior of the annular body has a through-hole, and the outer surface of the annular body is provided with at least one guide mass fitted to the guide groove of the cylindrical housing. One end of the output shaft is fitted to the second end of the nut member. The threaded shaft is connected to the nut member in a relatively movable manner, and the threaded shaft has an inner segment and an outer segment separated from each other in the longitudinal direction, wherein the inner segment of the threaded shaft is used to connect with a drive unit to rotate the threaded shaft, and the outer segment of the threaded shaft extends through the through hole of the rotation limiting member and the insertion hole of the nut member; when the threaded shaft rotates, the nut member, the rotation limiting member and the output shaft move in the longitudinal direction relative to the threaded shaft, and the guiding mass of the rotation limiting member moves in the longitudinal direction within the corresponding guiding groove, thereby restricting the rotation of the screw and the output shaft relative to the cylindrical housing.

[0006] In one embodiment of the present invention, the inner wall of the nut member is provided with a spiral inner groove, the outer side of the screw shaft is provided with a spiral outer groove, and a ball is disposed between the outer groove and the inner groove of the nut member, so that when the screw shaft rotates, the nut member is driven to move in the longitudinal direction relative to the screw shaft. An enlarged opening is provided inside the through hole at the first end of the nut member, and an obstruction ring is inserted into the opening.

[0007] In one embodiment of the present invention, the nut member has at least one mating groove on the outside, the annular body has a first surface and a second surface, and the first surface has at least one mating portion adapted to fit into the mating groove.

[0008] In one embodiment of the present invention, the engagement groove is an annular groove adjacent to a first end of the nut member, and the first surface of the annular body has a plurality of engagement portions spaced apart from one another in the circumferential direction, each engagement portion having a hook portion extending in the longitudinal direction and inserted into the engagement groove.

[0009] In one embodiment of the present invention, a plurality of guide grooves separated from one another in the circumferential direction are arranged on the hole wall of the receiving hole, and a plurality of guide blocks separated from one another in the circumferential direction are arranged on the outside of the annular body, each guide block fitting into a corresponding guide groove in the cylindrical housing. The guide blocks extend in the longitudinal direction and have two end portions separated from one another in the longitudinal direction, each end portion having a notch and two guide branches separated by the notch. The end portions of the guide blocks have a first width in the width direction, and the guide groove has a second width, the first width being the same as or slightly larger than the second width. An arc-shaped recess is provided in the center of the side surface of the guide block.

[0010] In one embodiment of the present invention, the second surface has a plurality of positioning portions separated from each other in the circumferential direction, each positioning portion extending in the longitudinal direction, and the sliding unit further includes an annular magnet, which is disposed on the second surface of the annular body and is located between the plurality of positioning portions and the guide mass of the rotation limiting member.

[0011] Other objects, advantages and features of the present invention may be understood from the following description of preferred embodiments with reference to the drawings. [Brief explanation of the drawings]

[0012] Figure 1 is an exploded view of some of the components of a general-purpose electric actuator. FIG. 2 is a composite cross-sectional view of FIG. FIG. 3 is a 3D diagram of the electric actuator of the present invention. FIG. 4 is an exploded view of the most partial components of the electric actuator of FIG. FIG. 5 is a vertical cross-sectional view of the electric actuator of FIG. FIG. 6 is a cross-sectional view of the electric actuator of FIG. FIG. 7 is a schematic diagram showing the sliding unit moving outward relative to the screw shaft in FIG. FIG. 8 is an exploded view of the components of the sliding unit of FIG. FIG. 9 is a schematic view showing that the screw shaft passes through the nut member and the rotation limiting member of the sliding unit in FIG. FIG. 10 is an assembly diagram showing the guide mass of the rotation limiting member being fitted into the guide groove of the cylindrical housing. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention may have embodiments that take on a variety of different configurations, and we will now describe, by way of example only and not limitation, specific embodiments of the preferred configuration of the invention with reference to the drawings.

[0014] 3 to 10 show an embodiment of an electric actuator 50 according to the present invention. The electric actuator 50 includes a cylindrical housing 52, a sliding unit 54 housed in the cylindrical housing 52, and a threaded shaft 56. The threaded shaft 56 is driven by a drive unit such as a motor 58 to linearly move the sliding unit 54 within the cylindrical housing 52. The motor 58 may be, for example, a servomotor or a step motor, and includes a rotating shaft 60. In this embodiment, the threaded shaft 56 is, for example, a ball screw shaft, and the threaded shaft 56 has an inner segment 61 and an outer segment 62 separated from each other in the longitudinal direction, and a spiral outer edge groove 63 is formed on the outer side of the threaded shaft 56. The inner segment 61 of the threaded shaft 56 is fitted into a mounting seat 64 and connected to a rotating shaft 60 of the motor 58, thereby allowing the threaded shaft 56 to be driven to rotate by the motor 58. The mounting seat 64 is connected between the motor 58 and the cylindrical housing 52, and an accommodation hole 66 (see FIG. 5) is provided inside the cylindrical housing 52 to accommodate the sliding unit 54 and the screw shaft 56. A plurality of guide grooves 68 (see FIG. 6) separated from one another in the circumferential direction are arranged in the hole wall of the accommodation hole 66 (the inner wall of the cylindrical housing 52), and the guide grooves 68 extend in the vertical direction. In this embodiment, four guide grooves 68 are arranged in the inner wall of the cylindrical housing 52.

[0015] A technical feature of the present invention resides in the sliding unit 54. The sliding unit 54 includes a rotation-limiting member 72, a nut member 70, and an output shaft 74 (see FIGS. 8-9). The nut member 70 is cylindrical and has a through-hole 76 extending in the longitudinal direction. The nut member 70 further has a first end 78 and a second end 80 separated from each other in the longitudinal direction. A spiral inner groove 82 (see FIG. 5) is provided on the inner wall of the through-hole 76 of the nut member 70, and the outer segment 62 of the screw shaft 56 extends through the through-hole 76 of the nut member 70. A ball 84 is disposed between the inner groove 82 and the outer edge groove 63 of the screw shaft 56, so that when the screw shaft 56 rotates, the nut member 70 is driven to move in the longitudinal direction relative to the screw shaft 56. In addition, the nut member 70 has at least one fitting groove 86 on the outer side, into which the rotation-limiting member 72 (see FIG. 9) is fitted. In this embodiment, the fitting groove 86 is an annular groove and is adjacent to the first end 78 of the nut member 70. The second end 80 of the nut member 70 is provided with an external thread 88 that fits onto the output shaft 74. Furthermore, the through hole 76 at the first end 78 of the nut member 70 is provided with an enlarged opening 90, into which an obstruction ring 92 is inserted to prevent the ball 84 from falling out (see FIG. 5).

[0016] As shown in FIGS. 8 and 9 , the rotation limiting member 72 has an annular body 94 that fits onto the first end 78 of the nut member 70. The annular body 94 has a through-hole 95 through which the screw shaft 56 passes. The annular body 94 has a first surface 96 and a second surface 98 that face away from each other in the longitudinal direction. The first surface 96 is provided with at least one fitting portion 100 that fits into the fitting groove 86 of the nut member 70. In this embodiment, the first surface 96 of the annular body 94 has a plurality of fitting portions 100 that are spaced apart from each other in the circumferential direction, and each fitting portion 100 has a hook portion 102 that extends in the longitudinal direction and is inserted into the fitting groove 86. The second surface 98 has a plurality of positioning portions 104 that are spaced apart from each other in the circumferential direction, and each positioning portion 104 extends in the longitudinal direction and has a hook portion 105. Furthermore, the annular body 94 has at least one guide block 106 on the outer surface that fits into the guide groove 68 of the cylindrical housing 52. In this embodiment, four guide blocks 106 are arranged circumferentially apart from one another on the outside of the annular body 94, and each guide block 106 fits into a corresponding guide groove 68 in the cylindrical housing 52 (see FIG. 6). When the nut member 70 moves in the longitudinal direction relative to the screw shaft 56, the guide blocks 106 move within the corresponding guide groove 68 in the longitudinal direction. In this embodiment, the guide blocks 106 extend in the longitudinal direction and have two end portions 108 separated from one another in the longitudinal direction, and each end portion 108 has a notch 110 and two guide branches 112 separated by the notch 110 (see FIG. 10). In this embodiment, the notch 110 forms an enlarged opening at the end face of the end portion 108 and has a V-shaped cross section. The end 108 of the guide block 106 has a first width (w1) in the width direction, and the guide groove 68 has a second width (w2), the first width (w1) being the same as or slightly larger than the second width (w2), so that the guide block 106 enters the guide groove 68 and contacts the groove wall of the guide groove 68 in response to pressure applied to the two guide prongs 112 of the end 108. Therefore, it is possible to ensure that the nut member 70 and the rotation limiting member 72 cannot rotate relative to the cylindrical housing 52 when the nut member 70 moves in the vertical direction relative to the screw shaft 56.Furthermore, a circular arc-shaped recess 116 is provided in the center of a side surface 114 of the guide block 106, which reduces friction between the guide block 106 and the groove wall of the guide groove 68, thereby ensuring that the guide block 106 slides smoothly inside the guide groove 68 and that the rotation limiting member 72 maintains its function of not rotating relative to the cylindrical housing 52 even after long-term use. In this embodiment, the rotation limiting member 72 is made of a wear-resistant material.

[0017] 7 and 8 , the output shaft 74 is a cylindrical hollow shaft, and its inner end 118 is fitted into the second end 80 of the nut member 70, so that when the threaded shaft 56 rotates, the output shaft 74 moves vertically together with the nut member 70. In this embodiment, the inner end 118 of the output shaft 74 is provided with an internal thread 120 that can be threadably engaged with the external thread 88 of the nut member 70. The outer segment 62 of the threaded shaft 56 passes through the through hole 76 of the nut member 70 and is positioned inside the output shaft 74. In this embodiment, the outer end 122 of the output shaft 74 is connected to a connecting member 124 that is used to connect an object driven by the electric actuator 50.

[0018] In this embodiment, the sliding unit 54 further includes an annular magnet 126 and an anti-collision ring 128. The anti-collision ring 128 is used to prevent collisions when the nut member 70 moves outward to a limit position. The annular magnet 126 is disposed on the second surface 98 of the annular body 94 and is located between the positioning portions 104 and the guide masses 106. The annular magnet 126 is fixed via the hook portions 105 (see FIG. 9 ) of the positioning portions 104 (see FIG. 9 ). The annular magnet 126 can sense the movement position of the nut member 70 in cooperation with a sensor (not shown). In one embodiment, the sensor is, for example, a magnetic reed switch disposed on the outside of the cylindrical housing 52.

[0019] In operation of the electric actuator 50 according to the present invention, when the motor 58 rotates clockwise or counterclockwise, the screw shaft 56 is driven to cause the nut member 70 and the output shaft 74 to extend or retract in the vertical direction inside the cylindrical housing 52. At this time, the guide mass 106 of the rotation limiting member 72 moves within the guide groove 68 of the cylindrical housing 52, thereby preventing the nut member 70 and the output shaft 74 from rotating relative to the cylindrical housing 52 during movement.

[0020] Considering that the sliding unit 54 of the present invention requires relatively few parts (including the nut member 70, the rotation limiting member 72, and the output shaft 74), it effectively simplifies the structure of the electric actuator 50, simplifies assembly of the electric actuator 50, and reduces fitting tolerances. Furthermore, the rotation limiting member 72 of the electric actuator 50 is convenient for assembling the nut member 70 and the cylindrical housing 52, ensures smooth sliding of the sliding unit 54 within the cylindrical housing 52, and effectively prevents rotation, potentially improving the operating precision of the electric actuator.

[0021] The above content describes the structure of the present invention as a more preferred embodiment, and various changes or modifications may be made according to the spirit of the present invention. Therefore, obvious substitutions and modifications that can be made by those skilled in the art should still be included within the claimed patent scope of the present invention. [Explanation of symbols]

[0022] 10 - cylindrical housing; 12-sliding units; 14-screw shaft; 16 - guide groove; 18-Sliding seat; 20-nut member; 22 - output shaft; 24-first end; 26 - second end; 28-through holes; 30-volts; 32-internal groove; 34-external marginal groove; 36-sphere; 38-mounting seat; 40 - guide mass; 42-volts; 50 - electric actuator; 52 - cylindrical housing; 54-sliding unit; 56 - screw shaft; 58 - motor; 60 - axis of rotation; 61-inner segment; 62-outer segment; 63 - outer marginal groove; 64 - mounting seat; 66 - containment pit; 68 - guide groove; 70 - Nut member; 72 - rotation limiting member; 74 - output shaft; 76 - penetration hole; 78-first end; 80 - second end; 82 - inner groove; 84-sphere; 86 - mating groove; 88 - external thread; 90 - opening; 92-Fault ring; 94 - annular body; 95 - through holes; 96-first surface; 98-second surface; 100 - mating part; 102, 105 - hook part; 104 - positioning part; 106-guiding mass; 108-end; 110-notched part; 112-Guiding branch; 114-side; 116 - arc-shaped recess; 118-inner end; 120 - internal thread; 122-outer end; 124-connecting members; 126 - ring magnet; 128-anti-collision ring; w1-1st width; w2 - Second width.

Claims

1. A cylindrical housing, a sliding unit, and a screw shaft are provided. The cylindrical housing has an interior with a receiving hole extending in a vertical direction, and at least one guide groove extending in the vertical direction is provided in a hole wall of the receiving hole; The sliding unit includes a rotation limiting member, a nut member, and an output shaft, the interior of the nut member having a through hole extending in the longitudinal direction, the nut member further having a first end and a second end separated from each other in the longitudinal direction, the rotation limiting member having an annular body fitted to the first end of the nut member, the interior of the annular body having a through hole, at least one guide mass adapted to be fitted to a guide groove of the cylindrical housing is provided on the outside of the annular body, and one end of the output shaft is fitted to the second end of the nut member; the threaded shaft is connected to the nut member in a relatively movable manner, and the threaded shaft has an inner segment and an outer segment separated from each other in a longitudinal direction, the inner segment of the threaded shaft is used to connect with a drive unit to rotate the threaded shaft, and the outer segment of the threaded shaft extends through the through hole of the rotation limiting member and the insertion hole of the nut member; when the threaded shaft rotates, the nut member, the rotation limiting member and the output shaft move in the longitudinal direction relative to the threaded shaft, and the guiding mass of the rotation limiting member moves in the longitudinal direction within the corresponding guiding groove, thereby restricting the rotation of the screw and the output shaft relative to the cylindrical housing; An electric actuator characterized by:

2. A spiral inner groove is provided on the hole wall of the through hole of the nut member, a spiral outer edge groove is provided on the outside of the screw shaft, and a ball is disposed between the outer edge groove and the inner groove of the nut member, so that when the screw shaft rotates, the nut member is driven to move in the longitudinal direction relative to the screw shaft, and an enlarged opening is provided inside the through hole at the first end of the nut member, and an obstruction ring is inserted into the opening.

2. The electric actuator according to claim 1.

3. At least one fitting groove is provided on the outside of the nut member, the annular body has a first surface and a second surface facing away from each other in the longitudinal direction, and the first surface has at least one fitting portion used to fit into the fitting groove.

2. The electric actuator according to claim 1.

4. The fitting groove is an annular groove adjacent to the first end of the nut member, and the first surface of the annular body has a plurality of fitting portions spaced apart from one another in the circumferential direction, each fitting portion having a hook portion extending in the longitudinal direction and inserted into the fitting groove.

4. The electric actuator according to claim 3.

5. a plurality of guide grooves spaced apart from one another in the circumferential direction are disposed on the hole wall of the receiving hole, and a plurality of guide blocks spaced apart from one another in the circumferential direction are disposed on the outside of the annular body, each guide block fitting into a corresponding guide groove in the cylindrical housing; 2. The electric actuator according to claim 1.

6. The guide mass extends in the longitudinal direction and has two ends separated from each other in the longitudinal direction, each end having a notch and two guide branches separated by the notch.

6. The electric actuator according to claim 5.

7. The end of the guide block has a first width in a width direction, the guide groove has a second width, and the first width is the same as or slightly larger than the second width.

7. The electric actuator according to claim 6.

8. 6. The electric actuator according to claim 5, wherein the arc-shaped recess is provided at the center of the side surface of the guide block.

9. the second surface has a plurality of positioning portions spaced apart from one another in the circumferential direction, each positioning portion extending in the longitudinal direction; the sliding unit further includes an annular magnet, the annular magnet being disposed on the second surface of the annular body and positioned between the plurality of positioning portions and the guide mass of the rotation limiting member; 4. The electric actuator according to claim 3.

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