JP2009038909A - Method and stopper device for deciding origin in actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a stopper device for decing an origin in an actuator which returns to an origin at high speed at an end of a work area and reduces the time for deciding an origin in equipment. <P>SOLUTION: In this method, a slider reciprocating in a certain work area by a driving mechanism provided in a housing is stopped at a stroke end. This method includes: installing a stopper device composed of buffer materials 25, 26 and rigid body portions 8, 9 at stroke ends; moving the slider 5 to a stroke end at normal driving speed and abutting it against the buffer materials 25, 26 of a stopper device to decelerate it; further actuating the slider 5 to press it against the stopper device at a speed significantly lower than the normal speed; and pushing the buffer material 25, 26 against the elasticity of the buffer material 25, 26 and stopping the slider 5 by the rigid body portions 8, 9 of the stopper device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an origin return method for an actuator and an origin return stopper device for an actuator that can return to the origin at a high speed at the end of an operating region and can shorten the time for returning the origin of the apparatus.

  In general, a single-axis robot actuator used as an industrial robot uses a servo motor or the like as a drive source, and a ball screw connected to the drive source is provided in an operation region. The ball nut is screwed in a state in which the rotation of the ball nut is restricted, and a slider is attached to the ball nut. Various devices that are operated in the operating region are mounted on the slider.

In this type of single-axis robot actuator, the ball screw is rotated in the same direction by rotating the servo motor in an appropriate direction, and the slider is moved in an appropriate direction via a ball nut that moves as the ball screw rotates. (See Patent Document 1).
After the slider moves to the position of the stroke end of the reciprocating motion, the slider is driven toward the position of the stroke end in the reverse direction.
Japanese Utility Model Publication No. 63-120552 JP 2003-309990 A JP 7-151205 A

When controlling the movement of the slider in this way, it is necessary to detect the rotational speed of the motor with an encoder, etc., and detect the position of the slider from the rotational speed, or provide a sensor at the stroke end to detect the reciprocating stroke position. There is.
Such a position of the stroke end is detected, and this position is set as an operation reference point, and the slider is controlled. The determination of the operation reference point is called origin search. For this origin detection, the control unit recognizes the origin position using a normal position detection sensor.
However, when a position detection sensor is used, there is a problem that wiring, installation space, and control objects increase.
Therefore, as a method that does not use the position detection sensor, there is an origin finding method that uses motor feedback control. As a method for determining the origin in this type of actuator, a method of recognizing the origin by pressing a slider against a stopper at the end of the operating region by using feedback control of the motor can be considered (see Patent Document 2).
However, when such a stopper uses an elastic body such as a rubber material as a buffer between the movable portion and the movable end (see Patent Document 3), the origin position reference can be reproducible due to the aging of the elastic body. There may not be. Further, when the stopper material is a metal rigid body, there is no buffering effect, and when returning to the origin, the actuator is pressed against the stopper at a low speed in order to avoid damaging the actuator. As a result, when the range of the movable range is wide, it takes time to complete the return to origin.

  The present invention provides an origin return method for an actuator and an origin return stopper device for an actuator that can solve the above-described problems, enable return to origin at a high speed at the end of the operating region, and can shorten the origin return time of the apparatus. The purpose is to do.

In order to solve the above-described problems, the present invention provides a method for returning to the origin of a stroke in an actuator in which a slider that is reciprocally operated in a certain operating region by a drive mechanism provided in a housing is stopped at the stroke end. , A stopper device comprising a cushioning material and a rigid body portion is disposed, the slider is moved to the stroke end at a normal driving speed, brought into contact with the cushioning material of the stopper device, decelerated, and the slider is further operated, The object is to press against the stopper device in an extremely low speed than the normal speed, push the buffer material against the elasticity of the buffer material, and stop the slider by the rigid portion of the stopper device to find the origin.
According to the present invention, an elastic body is used as the cushioning material, the elastic body is accommodated in a countersink hole formed in the rigid body portion, the elastic body is disposed so as to protrude from the rigid body portion, and the slider The elastic body in contact with the elastic body is elastically deformed in the counterbore hole, and then the slider is stopped by the rigid body portion, and the origin is set in a state where the slider and the rigid body portion are in contact with each other.
Furthermore, the present invention provides an origin stopper device for an actuator that stops a slider, which is reciprocated in a fixed operating region by a drive mechanism built in the housing, at the stroke end of the housing, and the stroke ends on both sides of the housing. Provided with a rigid body portion for stopping the slider, a concave portion is formed on a surface of the rigid body portion facing the slider, and an elastic body is disposed in the concave portion so as to protrude from the end surface of the rigid body portion, and the slider Is decelerated by the elastic body and then stopped at the origin by the rigid body portion.
Furthermore, the present invention lies in that a countersunk hole is formed in the rigid body portion, and the elastic body is accommodated in the countersink hole.
Further, the present invention resides in that a rubber material or a low resilience rubber material is used for the elastic body.

According to the first aspect, it is possible to give reproducibility to repeated origination without using a position detection sensor and without increasing the number of complicated control objects in the motor.
According to the second aspect of the present invention, since the elastic body in contact with the slider is elastically deformed in the countersink hole and is accommodated in the countersink hole, the slider can be stopped at a fixed position by the rigid body portion. The origin can be found at the position.
According to the third aspect, since the slider is stopped by the rigid body after the slider is decelerated by the elastic body, the origin can be returned at a high speed.
According to claim 4, since the elastic body can be accommodated in the counterbore, even if the elastic body is deformed due to aging, the standard for returning to the origin is always determined by the rigid body portion. Can keep.
According to the fifth aspect, since the speed of the slider can be effectively reduced, the origin can be obtained at a high speed, so that the origin finding time can be shortened.

Embodiments shown in the drawings will be described in detail below with reference to the drawings.
1 to 6 show a single-axis robot actuator, and FIG. 9 shows a sliding member assembled with a sheet. FIG. 10 is a diagram showing a movable slider.

  FIGS. 1 to 6 show a single-axis robot actuator, which is composed of a mechanism portion 1A and a drive portion 1B of the actuator 1. FIG.

  The mechanism portion 1A has a ball screw shaft 3 and a ball screw nut 4 built in a housing 2A, and a movable slider 5 that moves together with the ball screw nut 4 is provided on the upper surface of the housing 2A. The housing 2A includes a long linear guide rail 6 constituting the bottom surface, a pair of side covers 7 provided on both sides of the linear guide rail 6, and the linear guide rail 6 and the pair of side covers 7 in the front-rear direction. The flange 8 and the bracket 9 as rigid parts to be mounted on both sides, and the flange 8 and the bracket 9 are disposed along the opening groove 2a of the housing 2A so as to close the gap between the upper surfaces of the pair of side covers 7. The belt-shaped stainless steel sheet 10 is formed.

  One end of the ball screw shaft 3 is supported by the flange 8 via a rotary bearing 11, and the other end is supported by a bracket 9 via a rotary bearing 12. The other end of the ball screw shaft 3 is connected via a coupling 13 to a rotation shaft 14a of a servo motor 14 provided in the drive unit 1B.

  The movable slider 5 slides on the upper surface of the housing 2A in the longitudinal direction, that is, along the opening groove 2a. The movable slider 5 includes the pair of side covers 7 and the stainless sheet 10 as shown in FIG. On the upper side, a box-shaped table cover 15 disposed so as to cover a sliding member 16 to be described later, a sliding member 16 slidably mounted on the stainless steel sheet 10, and the sliding member 16 are held. In addition, a slider main body 17 that supports the operation target through the upper surface of the table cover 15 is provided. The slider body 17 is provided integrally with a linear guide block 18 slidably disposed along the linear guide rail 6, and moves along the ball screw shaft 3 along with the movement of the ball screw nut 4. It is reciprocated within 2A.

  As shown in FIGS. 10 (a), (b), (c) and FIGS. 11 (a), (b), the slider body 17 has support columns 17a erected at the four corners of the substantially rectangular upper surface, and the front-rear direction of the upper surface. A trapezoidal convex surface portion 17b formed on the slope is provided. The pair of front and rear struts 17a are provided so as to sandwich both sides of the convex surface portion 17b, and the front struts 17a and the rear struts 17a are connected by connecting members 17c. A mounting portion 17d serving as a screw hole such as a screw hole for supporting the object to be operated is provided on the upper surface of the column 17a. The stainless steel sheet 10 is assembled through a gap 17f between the convex portion 17b of the slider body 17 and the connecting member 17c (see FIG. 9). On the upper surface of the convex surface portion 17b of the slider body 17, two concave ridges 17e corresponding to respective resin shafts 21 of the sliding member 16 which will be described later are formed along the width direction. A screw hole 17g for assembling the table cover 15 is formed in the slider body 17 at the center of the upper surface of the connecting member 17c, and a protrusion 17i having a mounting hole 17h formed on the upper surface is formed on the outer surface of the column 17a. It protrudes outward.

As shown in FIG. 9, the sliding member 16 includes a pair of roller holders 19 composed of long resin plates facing each other at a predetermined interval, and between the front ends of the pair of roller holders 19 and A stainless steel shaft 20 ₁ , 20 ₂ connected to each other between the rear end portions and a resin shaft 21 connected to each other between the intermediate portions of the pair of roller holders 19 are configured. The roller holder 19 is formed in a long plate thin plate shape formed of a synthetic resin material, and a concave portion 19a having a predetermined length in the front-rear direction is formed on the outer side surface of the plate corresponding to the column 17a of the slider body 17. Are formed inward at two locations, and two notches 19b having a predetermined length are formed in the front-rear direction on the lower surface side.

As shown in FIG. 9, the shafts 20 ₁ and 20 ₂ are made of stainless steel, and are supported by a concave bearing housing 19 c formed on the inner surface on the front side and the rear side of the concave portion 19 a of the pair of roller holders 19. 22, and a plurality of elastic rollers 23 such as O-rings (two in the illustrated example) formed of an elastic body such as rubber are respectively provided on the shafts 20 ₁ and 20 _2. It is installed at intervals. The bearing housing 19c of the roller holder 19 is integrally formed when the roller holder 19 that is resin-molded is molded.

On the other hand, the resin shaft 21, as shown in FIG. 9, a concatenation of mutual intermediate portion of the roller holder 19, between the recesses 19a at two locations provided in the roller holder 19, the shaft 20 _1, than the position of 20 _2, taking into account the height of the convex portion 17b of the slider body 17, and is located slightly upward. In the embodiment, two resin shafts 21 are provided shifted in the longitudinal direction of the roller holder 19, but one or three or more resin shafts 21 may be provided as necessary. The resin shaft 21 has a large-diameter portion 21a having a large diameter and a small-diameter portion 21b having a small diameter that are alternately provided at regular intervals along the axial direction. Both ends of the resin shaft 21 may be fixed to the side surfaces of the roller holder 19 or may be assembled so as to be rotatable. Moreover, the large diameter part 21a and the small diameter part 21b should just be provided with unevenness | corrugation in the axial direction, and are provided with the difference of a diameter so that lubricating oil, such as grease, does not flow out outside.

As shown in FIG. 9, the sliding member 16 is connected to a support column 17 a of the slider body 17 and a connection to an opening 24 surrounded by a pair of roller holders 19, shafts 20 ₁ and 20 _2, and a resin shaft 21. The members 17c are combined and assembled to the slider body 17. The sliding member 16 is assembled to the slider main body 17 by engaging the notches 19b of the pair of roller holders 19 with the protrusions 17i of the slider main body 17, and the pair of roller holders 19 is assembled to the slider main body 17. It is positioned by being guided by the outer surface of the 17 support columns 17a. The resin shaft 21 of the sliding member 16 is disposed so as to correspond to the two concave stripes 17 e of the convex surface portion 17 b of the slider body 17.

The stainless steel sheet 10 passes through the upper surface of the resin shaft 21 from one of the gaps 17f between the convex surface portion 17b of the slider body 17 and the connecting member 17c through the lower opening of the shaft 20 ₁ (20 ₂ ) on one side of the sliding member 16. It is assembled through the gap 17f on the opposite side and through the lower surface side of the shaft 20 ₂ (20 ₁ ) of the sliding member 16 on the other side. The shafts 20 ₁ and 20 ₂ of the sliding member 16 are arranged outside the convex surface portion 17 b of the slider body 17 so as to press the stainless steel sheet 10 against the upper surfaces of the pair of side covers 7.

  As shown in FIG. 9, the table cover 15 is formed in a lid shape with a rectangular upper surface 15A and side wall surfaces 15B provided obliquely downward on four sides of the upper surface 15A. The slider body 17 is assembled so as to cover the member 16. Opening holes 15a are formed at the four corners of the upper surface 15A of the table cover 15 so as to correspond to the pillars 17a of the slider body 17, and the tips of the pillars 17a are assembled into the opening holes 15a. The object to be operated is assembled to the mounting portion 17d at the tip of the column 17a. Two attachment holes 15b are formed on both sides of the central portion of the upper surface 15A of the table cover 15. A screw (not shown) is passed through the attachment hole 15b and screwed into a screw hole 17g formed in the connecting member 17c of the slider body 17. Match. The side wall surface 15B in the width direction of the table cover 15 is provided with two concave portions 15c facing inward, and the concave portions 15c are connected to the engaging portions 17j provided on the projecting portions 17i of the slider body 17. An engaging opening 15d is provided.

As shown in FIGS. 4 to 8, the flange 8 and the bracket 9 are respectively provided with recesses 8 a and 9 a on the surface facing the movable slider 5, and the recesses 8 a and 9 a have a rubber material or Cylindrical elastic bodies 25 and 26 formed of a low resilience rubber material are disposed as cushioning materials. The elastic bodies 25 and 26 are disposed by bonding or press-fitting into the recesses 8a and 9a so as to protrude from the surfaces of the flange 8 and the bracket 9 as rigid bodies. Prior to this, the elastic bodies 25 and 26 are brought into contact with the movable slider 5 to reduce the speed of the movable slider 5.
Countersunk holes 8b and 9b are formed in the surfaces of the flange 8 and the bracket 9 around the elastic bodies 25 and 26 so as to increase the diameter of the recesses 8a and 9a on the entrance side. The flange 8 and the bracket 9 as the rigid body portions constitute stopper devices together with the elastic bodies 25 and 26 as the shock absorbing portions.
The flange 8 and the bracket 9 are provided with sheet pressers 27 and 28 for pressing the front and rear end portions of the stainless steel sheet 10.

  The motor 14 provided in the drive unit 1B is housed in a housing 2B, and a terminal cover 30 that houses a cable connector 29 that sends electric power and drive signals to the motor 14 at the rear end of the housing 2B. It is detachably attached. The terminal cover 30 is formed in a box shape so as to form a fixed space with the rear end of the motor 14, and a recess 30a is formed by notching one side of the lower side, and a cable 31 is formed on the lower surface side of the recess 30a. A passage hole 30b is formed to pass therethrough.

Next, a method for determining the origin of the actuator prior to the operation of the single-axis robot actuator will be described.
In the origin search, the movable slider 5 is driven at a normal speed and, for example, travels toward the flange 8. In the movable slider 5, the slider body 17 abuts on the elastic body 25 and deforms the elastic body 25. The elastic body 25 is crushed while being deformed, compressed into the countersink hole 8b, and stored in the countersink hole 8b. Thus, the movable slider 5 is stopped when the slider body 17 abuts on the surface of the flange 8 as the rigid body portion. In this way, positioning of one side is achieved and the origin is determined. Further, the same operation is possible in the reverse direction, the movable slider 5 is operated, the movable slider 5 is moved toward the bracket 9, the slider body 17 is brought into contact with the elastic body 26, and the elastic body 26 is compressed. Let Then, the elastic body 26 is deformed and stored in the counterbore 9b. The slider main body 17 is stopped in contact with the surface of the bracket 9 as a rigid body portion, and the origin is set. When the origin is thus found, the control unit starts to control the movable slider 5 with reference to this position.

Then, the control unit starts reciprocating control of the movable slider 5 based on the data obtained from the origin. During normal travel, when a drive signal is sent from the drive controller via the cable 31, the drive signal is sent to the motor 14 through the cable connector 29 to drive the motor 14 to rotate. The rotation of the motor 14 is transmitted to the ball screw shaft 3 through the coupling 13, and the ball screw nut 4 moves along the ball screw shaft 3 as the ball screw shaft 3 rotates. Then, the slider body 17 that moves integrally with the ball screw nut 4 starts moving together with the linear guide block 18 that is slidably disposed along the linear guide rail 6. In this way, the movable slider 5 moves together with the slider body 17, and the object to be operated attached to the movable slider 5 is moved. The movable slider 5 supports the stainless steel sheet 10 with the sliding member 16 inside the table cover 15, and holds the stainless steel sheet 10 by the elastic roller 23 and the resin shaft 21 of the sliding member 16. The stainless steel sheet 10 is assembled through the lower surface side of the elastic roller 23 of the one side shaft 20 ₁ (20 ₂ ), through the upper surface side of the resin shaft 21 and through the lower surface side of the elastic roller 23 of the other side shaft 20 ₂ (20 ₁ ). It has been. Since the elastic roller 23 of the sliding member 16 freely rotates together with the shafts 20 ₁ and 20 ₂ , the movable slider 5 can be moved smoothly. Further, since the resin shaft 21 of the sliding member 16 is made of synthetic resin, the stainless steel sheet 10 slides well, and the movable slider 5 can be moved efficiently.
In this way, the movable slider 5 is reciprocated along the opening groove 2 a by the ball screw shaft 3, and the object to be operated attached to the attachment portion 17 d of the movable slider 5 is controlled to reciprocate.

  According to the above embodiment, when the origins at both ends are set, the control unit starts control of the movable slider 5 with reference to this position, so that the reproducibility of the reference of the origin position is ensured and stable positioning is achieved. Since the reference is maintained, reliable reciprocation control can be performed. Since the elastic bodies 25 and 26 are elastically deformed and compressed in the counterbore holes 8b and 9b, the movable slider 5 comes into contact with the flange 8 and the bracket 9 to determine the origin position. Does not fluctuate. Therefore, reliable reciprocating drive can be performed.

In addition, the movable slider 5 is assembled integrally with the slider body 17 by assembling the sliding member 16 and covering the sliding member 16 with the table cover 15. Furthermore, the sliding member 16 is made of a pair of roller holders 19 formed of a resin material, and stainless steel shafts 20 ₁ and 20 _{2 in which} the front end portions and the rear end portions of the pair of roller holders 19 are connected to each other. A pair of roller holders 19 and a resin shaft 21 connected to each other between the middle portions of the pair of roller holders 19. A pair of O-rings or the like formed of an elastic body such as rubber is provided in the middle of the shafts 20 ₁ and 20 _2. Since the elastic rollers 23 are mounted at a predetermined distance from each other, they are lightweight and slip with the stainless steel sheet 10 is good. In addition, since the contact with the stainless steel sheet 10 is smooth, it is possible to improve the durability of the stainless steel sheet 10 without applying an unnecessary load to the stainless steel sheet 10.

  Furthermore, since the table cover 15 is put on the sliding member 16 and integrally assembled, the internal slider body 17 and the like are not visible from the outside by the side wall surface 15B, and the appearance can be improved. Dust and dust do not enter. Moreover, since the large diameter part 21a and the small diameter part 21b are provided in the resin shaft 21 which mutually connected intermediate parts, there is no possibility that lubricating oil, such as grease, will collect in the small diameter part 21b and leak outside. Furthermore, since the operated body can be attached to the movable slider 5 by attaching the operated body to the mounting portion 17d, the operated body can be firmly fixed. Since the movable slider 5 can be made compact, the overall length of the actuator 1 can be shortened and the size can be reduced. Furthermore, since the front columns 17a and the rear columns 17a are connected to each other by the connecting members 17c, the rigidity of the thin portion where stress is concentrated or the mounting portion of the operated body is secured. be able to.

  The present invention is not limited to the above-described embodiment. For example, in this embodiment, the movable slider 5 is in contact with the flange 8 and the bracket 9 which are rigid bodies to determine the origin position. However, the movable slider 5 is provided with a stopper 32 as shown in FIG. 4, and the stopper 32 is brought into contact with, for example, a fixed portion 33 provided on the flange 8 (or bracket 9) side so as to perform the origin search. It can also be. As a result, damage caused by contact between the flange 8 and the movable slider 5 can be prevented. In addition, it goes without saying that the present invention can be appropriately modified and implemented within the scope not changing the gist of the present invention.

It is a top view which shows the slider structure in the robot actuator by embodiment of this invention. It is a front view which shows the slider structure in the robot actuator by embodiment of this invention. It is the sectional view on the AA line of FIG. FIG. 3 is a sectional view taken along line B-B in FIG. 2. It is CC sectional view taken on the line of FIG. It is the DD sectional view taken on the line of FIG. It is the FF sectional view taken on the line of FIG. It is the GG sectional view taken on the line of FIG. It is a disassembled perspective view which shows the movable slider of FIG. The slider main body is shown, (a) is a plan view, (b) is a front view, and (c) is a right side view. (A) is the HH sectional view taken on the line of FIG.10 (b), (b) is the II sectional view taken on the line of Fig.10 (a). FIG. 10 is a cross-sectional view taken along line JJ of FIG. 9, showing a sliding member assembled with a stainless steel sheet.

Explanation of symbols

1 Actuator 1A Mechanism 1B Drive 2A, 2B Housing 3 Ball Screw Shaft 4 Ball Screw Nut 5 Movable Slider 6 Linear Guide Rail 7 Side Cover 8 Flange (Rigid Body)
8b Counterbore 9 Bracket (rigid part)
9b Counterbore hole 10 Stainless steel sheet 11, 12 Rotating bearing 13 Coupling 14 Servo motor (motor)
15 table cover 16 slide member 17 the slider body 17a strut 17b convex portion 17c connecting member 17d attachment portion 17e concave 18 linear guide block 19 Roller holder 19c bearing housing 20 _1, 20 ₂ stainless steel shaft 21 resin shaft 22 bearing 23 elastically Roller 24 Opening 25, 26 Elastic body 27, 28 Sheet presser 30 Terminal cover

Claims (5)

  In a method for determining the origin in an actuator for stopping a slider, which is reciprocated within a fixed operating range by a drive mechanism provided in a housing, at a stroke end, a stopper device comprising a cushioning material and a rigid body is provided at the stroke end. The slider device is moved to the stroke end at a normal driving speed and brought into contact with the buffer material of the stopper device to decelerate, and the slider is operated to operate the stopper device at an extremely low speed than the normal speed. A method of returning to the origin of the actuator, wherein the shock absorber is pushed against the elasticity of the shock absorber, the shock absorber is pushed in against the elasticity of the shock absorber, and the slider is stopped by the rigid portion of the stopper device.   The elastic body is used as the cushioning material, and the elastic body is accommodated in a countersink hole formed in the rigid body portion, the elastic body is disposed so as to protrude from the rigid body portion, and the elastic body is in contact with the slider 2. The body is elastically deformed in the counterbore hole, the slider is stopped by the rigid body portion, and the origin is determined in a state where the slider and the rigid body portion are in contact with each other. Origin return method for the actuator.   In a home position stopper device for an actuator that stops a slider that is reciprocated within a certain operating range by a drive mechanism built in the housing at the stroke end of the housing, the slider is stopped at the stroke ends on both sides of the housing. A rigid body portion is provided, a concave portion is formed on a surface of the rigid body portion facing the slider, an elastic body is disposed in the concave portion so as to protrude from the end surface of the rigid body portion, and the slider is decelerated by the elastic body. And then stopping at the origin position by the rigid body portion.   4. The origin stop stopper device for an actuator according to claim 3, wherein a counterbored hole is formed in the rigid body portion, and the elastic body is accommodated in the counterbored hole. 5.   5. The origin return stopper device for an actuator according to claim 3, wherein a rubber material or a low resilience rubber material is used for the elastic body.

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