KR20210028431A - Linear actuator - Google Patents

Abstract

According to an embodiment of the present invention, a linear actuator comprises: a housing having a predetermined space therein; a rotating shaft positioned inside the housing, extending in the longitudinal direction, and having an outer circumferential groove of a spiral shape formed along a circumferential surface; a nut portion into which the rotating shaft is inserted, an inner circumferential groove of an oblique shape facing the outer circumferential groove is formed, and which moves linearly as the rotating shaft rotates; a plate positioned above the nut portion; a driving portion disposed on one side of the housing to generate a driving force to rotate the rotating shaft; and a base bracket formed in a plate shape, longer than the width direction of the housing, and coupled to a lower part of the housing so that a part of an upper surface is exposed to the outside.

Description

Linear actuator {LINEAR ACTUATOR}

The present invention relates to a linear actuator.

Linear actuators are applied to various industrial machines as a shaft makes a linear motion by using a drive motor. The main application fields of these linear actuators are industrial robots or automatic control devices.

Various types of such linear actuators have already been known, and registered utility model No. 0426031 (name of the invention: servo linear actuator) and Korean Patent Publication No. 1997-0008794 (name of the invention: servo linear actuator) are disclosed.

In the case of the previously registered utility model, a screw is mounted inside the main body cover, and a reducer, a mini-motor, and a micro encoder are placed at the bottom of the screw, so that the screw moves up and down in a straight line. Both ends of the rotating ball screw are connected to the universal joint by means of a belt and a linear motion to realize a degree of freedom.

However, in order to fix the conventional linear actuator to the table, a separate bracket is used to fix it to the table, so there is a problem in that the accuracy is deteriorated. In addition, as a separate bracket is mounted on the actuator, the total volume and area of the actuator increases, it becomes difficult to mount the actuator in a narrow space, and the volume or size of the robot equipped with the actuator increases.

The present application is to solve the above-described problems of the prior art, and an object of the present invention is to provide a linear actuator capable of easily mounting an additional device such as a position detection sensor by mounting a base bracket on the lower portion of the housing.

However, the technical problem to be achieved by the present embodiment is not limited to the technical problems as described above, and other technical problems may exist.

As a technical means for achieving the above technical problem, the linear actuator according to an embodiment of the present application includes: a housing having a predetermined space therein; A rotating shaft located inside the housing, extending in a longitudinal direction, and having a helical outer circumferential groove along a circumferential surface; A nut portion into which the rotation shaft is inserted, a diagonal inner circumferential groove facing the outer circumferential groove is formed, and linearly moves as the rotation shaft rotates; A plate positioned above the nut part; A driving unit disposed on one side of the housing to generate a driving force to rotate the rotation shaft; It is formed in a plate shape, is formed longer than the length in the width direction of the housing, and includes a base bracket coupled to the lower portion of the housing so that a part of the upper surface is exposed to the outside.

In addition, the linear actuator further includes a plurality of position detection sensors for sensing the position of the nut part, and the position detection sensor is a plurality of magnetic sensors positioned at a predetermined distance apart from the longitudinal sidewall of the housing, or the base bracket It is a photo sensor that is located at the top of each other by a predetermined distance.

In addition, the base bracket is spaced a predetermined distance from each other along the length direction, a plurality of coupling holes perforated in the vertical direction; And a threaded portion through the coupling groove and coupled to the housing.

In addition, the threaded portion is coupled to the housing so as not to protrude downward from the base bracket.

In addition, it is located at one end of the rotation shaft, and includes a ball bearing that supports the rotation shaft so as to be rotatable.

Further, it is coupled to the drive unit and the rotation shaft, further comprising a coupling for transmitting the rotational force of the driving unit to the rotation shaft.

According to the above-described problem solving means of the present application, by mounting the base bracket on the lower portion of the housing, there is an effect that an additional device such as a position detection sensor can be easily mounted.

1 is a perspective view of a linear actuator according to an embodiment of the present invention.
2 is a cross-sectional view of a linear actuator according to an embodiment of the present invention.
3 is a cross-sectional view of a nut portion according to an embodiment of the present invention.
4 is a perspective view of a linear actuator according to another embodiment of the present invention.

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present application. However, the present application may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts irrelevant to the description are omitted in order to clearly describe the present application, and similar reference numerals are attached to similar parts throughout the specification.

Throughout this specification, when a part is said to be "connected" with another part, this includes not only the case that it is "directly connected", but also the case that it is "electrically connected" with another element interposed therebetween. do.

Throughout this specification, when a member is positioned “on” another member, this includes not only the case where a member is in contact with the other member, but also the case where another member exists between the two members.

In the entire specification of the present application, when a certain part "includes" a certain component, it means that other components may be further included, rather than excluding other components unless specifically stated to the contrary. The terms "about", "substantially", etc. to the extent used throughout the present specification are used at or close to the numerical value when manufacturing and material tolerances specific to the stated meaning are presented, and the understanding of the present application To assist, accurate or absolute numerical values are used to prevent unreasonable use of the stated disclosure by unscrupulous infringers. As used throughout the specification of the present application, the term "step (to)" or "step of" does not mean "step for".

The present application relates to a linear actuator (10).

1 is a perspective view of a linear actuator 10 according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a linear actuator 10 according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. It is a cross-sectional view of the nut part 210 according to this, and FIG. 4 is a perspective view of a linear actuator 10 according to another embodiment of the present invention.

Hereinafter, a linear actuator 10 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 and 2.

The linear actuator 10 includes a housing 100, a rotation shaft 210, a nut 220, a plate 300, a driving unit 400, and a base bracket 700.

The housing 100 may have an overall shape in a rectangular shape, the rotation shaft 210 and the nut 220 may be positioned, and the plate 300 may be exposed upward.

In addition, the base bracket 700 may be coupled to the lower surface of the housing 100. A detailed description of this will be described later.

The rotation shaft 210 is located inside the housing 100 and extends in the longitudinal direction, and a spiral outer circumferential groove 211 is formed along the circumferential surface. In other words, a spiral outer circumferential groove 211 may be formed on the circumferential surface of the rotation shaft 210 from one end to the other end.

In addition, referring to FIG. 2, the rotation shaft 210 has one end fixed to the housing 100 through a ball bearing 110, and the other end is directly connected to the driving unit 400 or connected to a coupling 500 to be described later, and the driving unit Driving force may be transmitted from 400.

The nut 220 has a rotation shaft 210 inserted therein, and a spiral inner circumferential groove 225 facing the outer circumferential groove 211 is formed. In other words, in the nut part 220, a hole into which the rotation shaft 210 is inserted may be perforated, and a spiral inner circumferential groove 225 may be formed along the inner circumferential surface of the perforated hole. In addition, the nut 220 may linearly move along the longitudinal direction of the rotation shaft 210 as the rotation shaft 210 rotates. A detailed description of this will be described later.

A plurality of balls 230 may be provided between the outer circumferential groove 211 of the rotation shaft 210 and the inner circumferential groove 225 of the nut 220. Accordingly, the nut 220 may be more smoothly moved in the longitudinal direction as the rotation shaft 210 rotates.

In addition, the nut part 220 may be formed in a rectangular parallelepiped shape, and a plurality of coupling grooves for mounting the plate 300 may be formed on the upper surface of the nut part 220. However, the present invention is not limited thereto, and the nut portion 220 may have a flat top surface and a predetermined shape.

The linear actuator 10 may further include a plate 300 coupled to the nut 220 of the ball screw 200.

The plate 300 is coupled to the nut 220 through a fastening member. In detail, the plate 300 may be fixed to the upper portion of the nut portion 220 through a coupling member that penetrates the plate 300 and is fastened to a coupling groove formed on the upper portion of the nut portion 220, but is not limited thereto. Does not.

The driving unit 400 may be disposed on one side of the housing 100 to generate a driving force to rotate the rotation shaft 210. As described above, the driving unit 400 may be directly connected to the rotation shaft 210 to transmit the driving force, but is not limited thereto, and as shown in FIG. 2, the driving force to the rotation shaft 210 through the coupling 500 Can also be delivered.

The ball bearing 110 may be positioned at one end of the rotation shaft 210 and support the rotation shaft 210 so as to be rotatable, as described above. Accordingly, the rotation shaft 210 may be smoothly rotated by receiving a driving force from the driving unit 400.

Referring to FIG. 2, the linear actuator 10 may further include a coupling 500 coupled to the driving unit 400 and the rotation shaft 210 to transmit the rotational force of the driving unit 400 to the rotation shaft 210. .

In other words, the coupling 500 connects the driving unit 400 and the rotation shaft 210 and transmits torque, and absorbs misalignment occurring between the driving unit 400 and the rotation shaft 210 to reduce the assembly adjustment load. have. In addition, when an unexpected overload occurs, the coupling 500 is destroyed, and the connection between the driving unit 400 and the rotating shaft 210 is released, so that the driving unit 400 and the entire device can be protected.

The linear actuator 10 is formed in a plate shape, and is formed longer than the length in the width direction of the housing 100, and includes a base bracket 700 coupled to the lower portion of the housing 100 so that a part of the upper surface is exposed to the outside. I can.

In addition, the linear actuator 10 may be mounted on the table through the base bracket 700. To this end, the linear actuator 10 may be fixed to the table as the fastening member penetrates the table and is lowerly fastened to the base bracket 700.

In addition, in order to be fixed to the housing 100, the base bracket 700 includes a plurality of coupling grooves 720 drilled in the vertical direction and a threaded portion 740 that is coupled to the housing 100 through the coupling groove 720. Can include. In addition, the coupling groove 720 has a step portion formed therein, so that the screw portion 740 may be coupled to the housing 100 so as not to protrude downward from the base bracket 700.

In addition, the base bracket 700 may include a plurality of fastening grooves 710 formed by spaced apart a predetermined distance along the length direction. When the linear actuator 10 is installed on the table, the coupling member is passed through the table from the bottom of the table, and the end is coupled to the fastening groove 710 of the base bracket 700 to prevent the linear actuator 10 from moving. Can be fixed on.

In other words, in order to precisely operate the linear actuator 10, it is installed so that the lower surface of the housing 100 is in close contact with the table. Since the lower surface of the housing 100 cannot be ground flat, the base bracket 700 ) To be flat by grinding the lower surface of the base bracket 700 to the lower portion of the housing 100, and then fixing the lower surface of the base bracket 700 so that the upper surface of the table is in close contact with the linear actuator ( It has the effect of remarkably improving the precision of 10).

A sensing unit coupled to one side of the position detection sensor 610 and the plate 300, respectively installed at a predetermined distance apart from one side of the housing 100 in the longitudinal direction, and the lower end of the position detection sensor 610 It may further include (310). The above-described longitudinal direction may be the 12 o'clock and 6 o'clock directions of FIG. 2. For example, the position detection sensor 610 may be a photosensor 610.

Specifically, when the linear actuator 10 is driven, the plate 300 moves linearly and reciprocally in the longitudinal direction, and as the plate 300 moves, the sensing target 310 attached to the plate 300 is a photosensor. When it reaches 610, it is possible to control the linear actuator 10 to stop driving or to rotate in the opposite direction. In addition, the photosensor 610 is coupled to the upper surface of the base bracket 700 so that the position can be easily changed, and accordingly, the user can set the movement limit point of the plate 300.

As described above, since the base bracket 700 is located under the housing 100 in the linear actuator 10, an additional device such as a photo sensor 610 can be easily mounted.

Hereinafter, with reference to Figure 3, the nut 220 of the present invention will be described in detail.

As described above, a plurality of balls 230 are positioned between the outer circumferential groove 211 of the rotation shaft 210 and the inner circumferential groove 225 of the nut part 220 in the nut part 220, and the plurality of balls 230 ) While circulating, the driving force of the rotating shaft 210 can be smoothly transmitted.

The nut part 220 is located inside the recessed part 222, the recessed part 222, which is formed inwardly to a predetermined depth in the central part of the upper surface, and the ball 230 of the ball screw 200 is circulated. It may include a circulation path 223, and a cover portion 224 covering the circulation path 223.

Specifically, the plurality of balls 230 can be moved from one side to the other side or in one direction from the other side along the outer circumferential groove 211 of the rotation shaft 210 and the inner circumferential groove 225 of the nut 220, and one end The ball 230 moved to may be moved to the other end along the circulation path 223. In addition, when the ball 230 is separated or deformed, the cover part 224 is opened to add the ball 230 or the ball screw 200 may be repaired.

Hereinafter, a linear actuator 10 according to another embodiment of the present invention will be described in detail with reference to FIG. 4.

The linear actuator 10 according to another embodiment of the present invention is characterized in that it includes a plurality of magnetic sensors 620 positioned at a predetermined distance apart from the longitudinal sidewall of the housing 100. For example, the magnetic sensor 610 may be inserted into a groove formed in a sidewall of the housing 100 (a groove formed to correspond to the longitudinal direction of the housing), but is not limited thereto.

In other words, when the linear actuator 10 is driven, the plate 300 linearly reciprocates in the longitudinal direction, and when the nut 210 reaches the magnetic sensor 620 as the plate 300 moves, the magnetic The sensor 620 detects a magnetic field relative to the ball screw of the nut part 210 to determine where the nut part 210 is currently located, so that the linear actuator 10 may be controlled. In addition, the magnetic sensor 620, as shown in Figure 4, each positioned at the movement limit point of the nut portion 210, it can be controlled so that the nut portion 210 does not collide with the housing 100, but this Without limitation, a plurality of magnetic sensors 620 may be provided to detect the exact position of the nut part 210, and thus may be used in various fields in industrial fields. When performing laser irradiation or cutting among semiconductor equipment, the nut part 210 is moved to move the laser equipment or cutting equipment. At this time, depending on where the nut part 210 is, it is possible to know where the laser equipment or cutting equipment is, but the nut part 210 is moved by a motor command, but it is difficult to know the position measurement after the actual movement by the motor value. Therefore, the actual position of the nut part 210 can be more precisely grasped through the magnetic sensor 620.

As a further embodiment, a temperature change detection sensor may be mounted on one side of the housing of the linear actuator 10. When the linear actuator 10 is used in an industrial site, it may be exposed to high temperatures or generate high heat depending on the industrial site environment or the type of equipment used.In this case, thermal degeneration of the linear actuator may occur. At this time, since it affects the length or width of the linear actuator, an error may occur in the position measured through the position sensor compared to the position when the product was initially delivered and used. Therefore, the temperature change detection sensor can detect whether the length or width of the linear actuator is extended due to thermal denaturation by setting the reference point on the other side of the linear actuator and then calculating the distance to the reference point in real time. . In addition, the current position value may be adjusted by subtracting or adding a value corresponding to the extended length or width to the current position value sensed through the position sensor. This can be a huge advantage because the control of several millimeters is very important in the semiconductor process.

As a further embodiment, based on a magnetic signal detected by a plurality of magnetic sensors 620 arranged to be spaced apart from each other on one side of the housing and a magnet additionally provided in the nut part 210, additionally provided on one side of the linear actuator A controller for sensing the current applied to the coil may be additionally provided. Such a controller can monitor whether the actuator operates periodically and regularly when it is actually operating in an industrial field. Specifically, as the nut part 210 regularly reciprocates, the magnetic sensor generates a periodic and regular magnetic signal, and informs at which point the nut part 210 is located. Through this, the controller can monitor whether the nut part reciprocates at a regular position and movement period. Further, the magnet of the nut part generates a current by applying an inductive magnetic field to the coil provided on one side of the housing. Since the nut part will reciprocate periodically, the current must also generate a periodic value. Accordingly, the controller can more accurately determine whether the nut 210 performs a normal and regular operation based on the current value of the coil. If it is determined that there is a deviation from the regular operation, a notification and actuator identification information are provided to the user terminal through a communication unit (not shown) connected to the linear actuator, thereby indicating which linear actuator of which equipment has a problem.

The foregoing description of the present application is for illustrative purposes only, and those of ordinary skill in the art to which the present application pertains will be able to understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present application is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present application.

10: linear actuator
100: housing 110: ball bearing
210: rotating shaft 211: outer circumferential groove
220: nut part
222: depression 223: circulation path
224: cover 225: inner circumferential groove
230: ball
300: plate 310: sensing target
400: drive unit
500: coupling
610: magnetic sensor 620: photo sensor
700: base bracket 710: fastening hole
720: coupling hole 740: threaded portion

Claims (6)

In the linear actuator,
A housing having a predetermined space therein;
A rotation shaft located inside the housing, extending in a longitudinal direction, and having a helical outer circumferential groove along a circumferential surface;
A nut portion into which the rotation shaft is inserted, a diagonal inner circumferential groove facing the outer circumferential groove is formed, and linearly moves as the rotation shaft rotates;
A plate positioned above the nut part;
A driving unit disposed on one side of the housing to generate a driving force to rotate the rotation shaft; And
A linear actuator comprising a base bracket that is formed in a plate shape, is formed longer than a length in the width direction of the housing, and is coupled to a lower portion of the housing so that a part of the upper surface is exposed to the outside. The method of claim 1,
Further comprising a plurality of position detection sensors for sensing the position of the nut portion,
The position detection sensor is a plurality of magnetic sensors positioned at a predetermined distance apart from the longitudinal sidewall of the housing, or a linear actuator which is a photo sensor positioned at a predetermined distance above the base bracket. The method of claim 1,
The base bracket is
A plurality of coupling holes spaced apart from each other at a predetermined distance along the longitudinal direction and perforated in the vertical direction; And
The linear actuator comprising a threaded portion coupled to the housing through the coupling groove. The method of claim 3,
The linear actuator is coupled to the housing so that the screw portion does not protrude downward from the base bracket. The method of claim 1,
A linear actuator comprising a ball bearing positioned at one end of the rotation shaft and supporting the rotation shaft to be rotatable. The method of claim 1,
The linear actuator is coupled to the driving unit and the rotation shaft, further comprising a coupling for transmitting the rotational force of the driving unit to the rotation shaft.

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