JPH05118405A - Rectilinear operating unit - Google Patents

Abstract

PURPOSE:To constitute a rectilinear operation unit simply and inexpensively in which a plurality of movable members are driven in lateral symmetry by a single driving means, by screwing a plurality of nut blocks with the left and right screw parts and carrying out impulse drive through a number of rolling bodies interposed between a guide rail. CONSTITUTION:When the shaft edge part 7B of the first screw shaft 7 is drive- revolved, e.g. rightward by a motor not shown on the figure, the first nut block 15 and the second nut block 28 shift in the separating direction, since the first nut block 15 is screwed with the right screw part 7A of the first screw shaft 7, and the second nut block 28 is screwed with the left screw part 13A of the second screw shaft 13. At this time, the impulse resistance between both the nut blocks 15 and 28 can be reduced, since a number of balls 19 are fitted in free rolling in the ball rolling grooves 17 and 2 of both the nut blocks 15 and 28 and a guide rail 1. The balls 19 roll, accompanied with the shift of both the nut blocks 15 and 28, and circulate in a circulation passage consisting of the curved passage 33 on an end cap 27 and a return passage 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear operating unit used in robots and measuring devices.

[0002]

2. Description of the Related Art A nut block guided by a guide rail is designed to be moved in a predetermined amount in the axial direction according to the rotation of a screw shaft driven by a motor for use in a simple robot operating arm or measuring device. As a linear operation unit,
For example, the one disclosed in Japanese Utility Model Laid-Open No. 63-193637 is known.

[0003]

In a measuring device or the like, it is necessary for two movable members to move left and right symmetrically with respect to a reference line. However, such a linear operating unit is one of the conventional ones. Is not known. In order to realize such an operation with a conventional linear actuation unit, when two units are provided in series and the movable member of one unit is moved in one axial direction, the other movable member is moved by one movable unit. It is necessary to move the members in a predetermined relative relationship so as to correspond to the opposite directions. In such a case, the moving accuracy of the two movable members in the straight direction,
There is a problem that it is difficult to obtain the synchronism of the lateral movement and the correct relative positional relationship between both movable members.

Further, if two units are used, it is inevitable that they cannot be made light and compact, the number of parts is increased, and the cost becomes high.

In view of the above-mentioned problems of the conventional example, the present invention is a linear actuation unit in which two movable members are driven symmetrically by one driving means, and the handling is simple and the accuracy is high. It is an object of the present invention to provide a compact and inexpensive linear actuation unit whose relative position can be easily adjusted.

[0006]

A linear actuation unit of the present invention has long guide rails having axial rolling element rolling grooves on opposite side surfaces thereof, and a right-hand thread portion on an outer peripheral surface thereof. A first screw shaft disposed in the axial direction of the rail and rotatably fixed to the guide rail, and disposed in the axial direction having the same shaft center as the first screw shaft. A second screw shaft having a left screw portion on the outer peripheral surface, and the first screw shaft at a position where the phase of the ball screw groove of the screw portion of the second screw shaft is adjusted with respect to the first screw shaft. A rolling element rolling groove that opposes the rolling element rolling groove of the guide rail and has a return passage for the rolling element that is formed within the wall thickness. The first nut block slidably engaged with the first screw shaft and the rolling element rolling groove of the guide rail. A second nut block slidably screwed to the second screw shaft, having a rolling member rolling groove facing the rolling member and having a rolling member return passage formed in the wall thickness; The rolling element rolling groove of the rail and the first groove facing the rolling groove.
The rolling element rolling groove of the nut block and the rolling element rolling groove of the second nut block are rotatably fitted in the first nut block and the second nut block, respectively. A passage formed by a large number of rolling elements supported slidably in the axial direction with respect to the guide rail, rolling element rolling grooves of the guide rail, and rolling element rolling grooves of the nut block facing the rolling element rolling grooves. And a end cap having a curved passage for rolling element circulation that connects the passage for the rolling element that rolls under the load from the nut block and the return passage of the rolling element of the nut block. By doing so, the above object is achieved.

[0007]

According to the linear operation unit of the present invention, the coupling is performed at a position where the relative relational position (phase) of the ball screw grooves of the first screw shaft having the right-hand screw part and the second screw shaft having the left-hand screw part is adjusted. Both screw shafts are fixed by means of the above, and nut blocks are independently screwed into the right-hand screw part of the first screw shaft and the left-hand screw part of the second screw shaft, respectively, and the rolling element rolling groove provided in the guide rail. The rolling element is disposed between the rolling element and the rolling element rolling groove provided in the nut block, and the nut block is slidable in the axial direction through the rolling of the rolling element. By rotating the shaft, a linear operating unit is obtained in which the two nut blocks move in opposite lateral directions in an adjusted relative positional relationship, and the second screw shaft is moved by a predetermined amount in the circumferential direction with respect to the first screw shaft. Fixed by coupling while rotating to Phases of the screw shaft is changed by the. Since this nut block moves by being guided by the rolling element rolling groove formed in the axial direction of the guide rail, parallelism in the operating direction of both nut blocks can be secured. In addition, since it is built into the same guide rail, it is not bulky and requires a small number of parts.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

The guide rail 1 is a long rail member as shown in FIG. 1, and has a U-shaped cross section whose bottom is open at the bottom.
Ball rolling grooves 2, which are one rolling element rolling groove extending in the axial direction, are formed facing each other on the inner surfaces of both side wall portions 1B, 1B extending upward from both ends of A (see FIG. 6). ).
Then, circular bolt holes 3 for the guide rail mounting bolts are provided in the bottom portion 1A at a position close to both side wall portions 1B in a state of being spaced apart by a predetermined distance in the axial direction. This guide rail 1
The bearing plate 4 is attached by screwing it with bolts 5 at the right end in the length direction of. The bearing plate 6 is attached to the left end of the guide rail 1 by bolts 38.

The first screw shaft 7 has a right-hand threaded portion 7A over substantially the entire length of the outer peripheral surface thereof and is arranged in the longitudinal direction of the guide rail 1 and has ball rolling grooves 2 provided on both side wall portions 1B and 1B of the guide rail. It is parallel to 2 and is arranged at an intermediate position between both side wall portions 1B and 1B. One end of the first screw shaft 7 has a ball bearing (not shown) fitted to a housing 9 of a support unit mounted on the bearing plate 4 with bolts 8.
Is rotatably supported by the lock nut 10 so that it cannot be moved in the axial direction. A holding lid 11 for fixing the outer ring side of the ball bearing is fixed to the outer end surface of the housing 9 by a bolt 12. Second
The screw shaft 13 has a left-hand threaded portion 1 over almost the entire length of the outer peripheral surface.
3A, has the same axis as the first screw shaft 7, and is arranged in the axial direction. First supported on the support unit
End opposite to the end of the screw shaft and the second opposite end
One ends of the screw shafts are fixed to each other via a coupling 16 at a position where the phase of the second screw shaft 13 in the rotational direction is adjusted with respect to the first screw shaft 7. The coupling 16 and the end of the screw shaft are fixed by tightening a set screw 39 screwed to the coupling 16.
The other end of the second screw shaft 13 is inserted into the bearing fitted to the bearing plate 6, and the retaining ring 14 is engaged with the shaft end to prevent the bearing from coming off.
The end of the screw shaft 13 is supported. The right-hand threaded portion 7A of the first screw shaft and the left-handed thread portion 13A of the second screw shaft have substantially equal lengths. The shaft end 7B of the first screw shaft is a shaft portion for mounting the rotary joint, and is connected to the drive motor for rotating the first screw shaft 7 by the rotary joint.

The lower portion of the first nut block 15 is inserted into the U-shaped guide rail 1, and a ball rolling groove 17 is formed at a position facing the ball rolling groove 2 of the guide rail. A ball return passage 18 is formed as an axial through hole in the wall thickness of the first nut block 15 so as to correspond to the ball rolling groove 17. In the first nut block main body 15A, a right-handed screw portion 2 that is screwed into a right-handed screw portion 7A of the first screw shaft via balls 19 that are rolling elements.
0 is formed. Both end portions of the nut block body 15A extend upward, and the upper surface thereof has screw holes 2 for a user to attach a member such as a table in use.
1 is provided (see FIG. 7). A recess 22 is formed in the center of the upper surface of the nut block body 15A, and a hole 23 for inserting a ball circulation tube is formed in the bottom of the recess 22. A U-shaped ball circulation tube 36 is inserted into the hole 23, and the ball circulation tube 36 forms a passage for circulating the balls 19. The ball circulation tube 36 is the first nut block body 1
It is fixed via a metal fitting 25 by a bolt 37 that is screwed into a screw hole 24 provided in 5A. The screw hole 26 provided in the end surface of the first nut block body 15A is for attaching an end cap 27 described later.
The second nut block 28 is the screw portion 13 of the second screw shaft.
The only difference is that the threaded portion that is screwed with A via a ball is a left-hand thread, and the first nut block 1
Since it has the same configuration as that of No. 5, detailed description will be omitted.

The end caps 27 are fitted into fitting holes 31 having large diameters at the entrances of the screw holes 26 provided at both ends of the first nut block body 15A and the second nut block body 28A, respectively. Positioned by fitting the protruding portion 30 that is cylindrically protruded to the end surface of the
The side seal 35 is brought into contact with the outside of the end cap 27, and the screw 3 is inserted through the side seal 35.
The end cap 27 is fixed by 2. The side seal 35 prevents dust adhering to the ball rolling groove 2 of the guide rail or the screw portions 7A and 13A of the screw shaft from entering the rolling portion of the inner ball. The ball rolling groove 2 of the guide rail and the first nut block and the second nut block facing the ball rolling groove 2 of the guide rail are provided on the joint end surface of the end cap 27 that abuts on the first nut block body 15A and the second nut block body 28A. Ball circulation for communicating the passage for the rolling element which is formed by the respective ball rolling grooves 17 and which rolls under the load with the return passages for the balls of the first nut block and the second nut block. A curved passage 33 for use is formed. A return guide 34 that guides the inner portion of the rolling ball is fitted in the inner portion of the ball circulation curved passage 33.

The ball rolling groove 17 of the first nut block and the second nut block and the ball rolling groove 2 of the guide rail.
A large number of balls 29 are rotatably fitted between them.

In use, the linear operating unit of the present invention is driven by connecting the shaft end 7B of the first screw shaft and the output shaft of the motor with a rotary joint to rotationally drive the motor.

The side seal 35 receives an impact when the first nut block 15 and / or the second nut block 28 collides with the bearing plate 4 and / or the bearing plate 6 or the coupling 16 due to a runaway of the motor or the like. It is configured to have an annular protruding portion made of a rubber material that absorbs, and this protruding portion functions as a cushion.

The first nut block 15 is screwed with the right screw portion 7A of the first screw shaft, and the second nut block 28 is screwed with the left screw portion 13A of the second screw shaft. Therefore, when the first screw shaft 7 is rotated clockwise, the first nut block 15 and the second nut block 28 move in the directions away from each other. At this time, the ball 2 is placed between the ball rolling groove 17 of the nut block and the ball rolling groove 2 of the guide rail.
Since the nut block 9 is rotatably fitted and the nut block is supported by rolling balls, the sliding resistance of the nut block can be reduced and a motor with a small capacity can be used.

The balls 29 roll as the nut block moves, and the balls 29 move in the curved passage 3 of the end cap.
3 and the return passage 18 circulate in the circulation passage. There is a ball 19 between the thread part of the nut block and the thread part of the screw shaft.
To form a ball screw, and the rotation of the screw shaft causes the ball 19 to move along with the movement of the nut block while rolling between the screw part of the screw shaft and the screw part of the nut block to form a ball circulation tube. The pushed ball circulates in the ball circulation tube.

When the first screw shaft 7 is rotated counterclockwise as opposed to the above-mentioned rotation, a movement opposite to the above is obtained, and the first nut block 15 and the second nut block 28 move toward each other. .. In the linear operation unit of the present invention, the first screw shaft 7 and the second screw shaft 13 are fixed by the coupling 16. The coupling is a hollow cylindrical member, and the first screw shaft 7 and the second screw shaft 13 are rotatably fitted in the hollow hole. A screw hole 40 is provided in the outer peripheral surface of both ends of this coupling, and a set screw 39 is screwed into this screw hole, and both screw shafts are fixed at a position rotated by a predetermined amount with respect to the coupling. be able to. Therefore, the adjustment of the phase of the second screw shaft 13 with respect to the first screw shaft 7 is possible for any dimension smaller than the pitch of the screw shaft. With such a structure, when the first nut block 15 is set at a predetermined position with respect to the guide rail 1, even if the second nut block 28 is displaced from the predetermined position, the coupling is stopped. Loosen the screw 39 and rotate the screw shaft to adjust the second nut block 28 to a predetermined relational position with respect to the first nut block 15, and tighten the set screw 39 at this position to tighten the first and first nut blocks. The two screw shafts may be fixed. In this case, the hexagonal holes 41, 4 are provided at the ends of the first screw shaft 7 and the second screw shaft 13.
2 is provided. Insert a hexagon wrench into these hexagon holes 41 and 42 to hold the hexagon wrench on the side of the hexagon hole 41 by hand to prevent the first screw shaft from rotating, and use the hexagon wrench on the side of the hexagon hole 42. The position of the second nut block 28 can be easily adjusted by rotating the second screw shaft.

The pitch of the right-hand thread and the pitch of the left-hand thread of the linear operation unit of this embodiment are made equal, and the nut blocks of the same dimension are used. Therefore, when the feed screw is rotated, the movement of each nut block is in the opposite direction and the speed is the same. Since the weight of the nut block is equal, the vibration when the nut block is stopped is offset and the positioning can be performed in a short time. There are advantages.

The ball rolling groove 2 having the ball rolling groove portion of the guide rail 1 for guiding the first nut block 15 and the ball rolling groove portion of the guide rail for guiding the second nut block 28 is Since the set of workpieces for groove processing is a groove processed over the entire length with the same set, straightness, parallelism, etc. are precise and movement of both nut blocks does not occur because the movement axis of each nut block does not shift. Accuracy is secured.

Although a ball screw is used as the feed screw in the above embodiment, a slide screw may be used instead of the ball screw. In this embodiment, ball rolling grooves are formed on both inner side surfaces. Although the example using the formed guide rail is shown, the guide rail having ball rolling grooves on both outer side surfaces of the guide rail may be used.

Further, in the above-mentioned embodiment, an example is described in which the right screw portion 7A of the first screw shaft and the left screw portion 13A of the second screw shaft have the same pitch. The first nut block may be a left-hand thread and the second nut block may be a right-hand thread.

Furthermore, in this embodiment, an example of an external circulation type ball screw using a circulation tube as the ball screw has been described, but an internal circulation type ball screw or an end cap that circulates a ball using a top is used. You may use the ball screw which circulates the ball passage provided in the nut block.

Furthermore, in this embodiment, a cylindrical coupling is used, but the shape is not limited to that of this embodiment as long as the phase of the two screw shafts can be adjusted, and various modifications are possible. It is possible.

Further, in this embodiment, a circular bolt hole is provided as a mounting hole for the guide rail, but an axial elongated hole 43 as shown in FIG. 11 may be used. This long hole 4
By using No. 3, when precisely mounting the guide rail to the mounting position of the base, it is possible to adjust the position of the nut block easily because precise adjustment can be made while watching the movement by applying a dial gauge to the guide rail. A linear actuation unit is obtained.

In this embodiment, an example is shown in which the end cap is fixed to the end surface of the nut block to circulate the balls. However, not limited to such an end cap, a known means such as a tube for circulating the balls. Etc. can also be used.

[0027]

According to the linear operation unit of the present invention, the first screw shaft having the right-hand screw part and the second screw shaft having the left-hand screw part are coupled to each other by a ball screw groove of the screw part between the screw shafts. Of the first threaded shaft and the left threaded part of the second threaded shaft are independently screwed together, and the rolling elements provided on the guide rails are fixed. Since the rolling element is fitted between the rolling groove and the rolling element rolling groove provided in the nut block and the nut blocks are slid through the rolling of the rolling element, the two nut blocks are 2 of the linear operation unit that operates accurately while maintaining the relative positional relationship adjusted in the left and right opposite directions
The relative position of the two nut blocks can be adjusted for any size smaller than the pitch of the screw shaft, and since it is unitized, it is easy to use. Further, since the linear operation unit of the present invention has a small sliding resistance of the nut block, a small motor can be used, the number of parts is small and the weight is light, and the present invention can provide a compact and inexpensive linear operation unit. .. Further, since the two nut blocks of the linear operation unit according to the present invention move by being guided by the same rolling element rolling groove provided on the guide rail, the parallelism at the time of operation of both nut blocks is secured. It is possible, and it is not necessary to make it difficult to align the axes of the two nut blocks. Furthermore, by setting the pitch of the right-handed screw portion provided on the first screw shaft and the left-handed screw portion provided on the second screw shaft to a predetermined pitch, the two nut blocks can be moved to the desired left-right movement. It can be obtained by controlling one screw shaft.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a front view of FIG.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a left side view of FIG.

FIG. 5 is a right side view of FIG.

6 is a cross-sectional view taken along the line BB of FIG.

FIG. 7 is a perspective view of the component of FIG.

FIG. 8 is a perspective view of the component of FIG.

9 is a cross-sectional view taken along the line CC of FIG.

10 is a perspective view of the component of FIG. 1. FIG.

FIG. 11 is a plan view of another embodiment of the guide rail of FIG.

[Explanation of symbols]

 1 guide rail 2 ball rolling groove 4 bearing plate 6 bearing plate 7 first screw shaft 7A right screw part 7B shaft end 13 second screw shaft 13A left screw part 15 first nut block 16 coupling 17 ball rolling Groove 18 Ball return passage 19 Ball 20 Screw portion 27 End cap 28 Second nut block 29 Ball 34 Return guide

Claims (1)

[Claims] 1. A long guide rail having axial rolling element rolling grooves on opposite side surfaces thereof, and a right-hand threaded portion on an outer peripheral surface, the guide rail being arranged in the axial direction of the guide rail, and the guide rail. A first screw shaft rotatably supported with respect to the first screw shaft;
Second screw shaft having the same axial center as the screw shaft and arranged in the axial direction and having a left-hand screw portion on the outer peripheral surface; and a screw portion of the second screw shaft with respect to the first screw shaft. A coupling for fixing the first screw shaft and the second screw shaft at a position where the phase of the ball screw groove is adjusted, and a rolling element rolling groove facing the rolling element rolling groove of the guide rail. A first nut block slidably engaged with the first screw shaft and having a return passage for the rolling element formed within the wall thickness; and a rolling element rolling groove of the guide rail. A second nut block slidably screwed to the second screw shaft, having a rolling element return groove formed in the wall thickness and having opposing rolling element rolling grooves, and the guide. The rolling element rolling groove of the rail, the rolling element rolling groove of the first nut block and the rolling element rolling groove of the second nut block which face the rail. A large number of rolling elements that are respectively rotatably fitted in the body rolling grooves and that support the first nut block and the second nut block slidably in the axial direction with respect to the guide rails. And a passage formed by the rolling element rolling groove of the guide rail and the rolling element rolling groove of the nut block that faces the rolling groove, which is for a rolling element that receives a load from the nut block and rolls. A linear actuation unit comprising: a passage and an end cap having a curved passage for rolling element circulation, which communicates the return passage of the rolling element of the nut block.