JP2000320638A - Linear movement guide device with feed screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately stop a moving block at a desired position by constituting the moving block defining an inside rolling face in the outside face of a pair of sidewalls of an approximately U-shaped sectional steel member having its bottom opened and a molding member filling the inside. SOLUTION: A plurality of endless circuit track 108 having a lot of rolling elements 103 circulatively moving are formed in a moving block 101 freely moving along an approximately U-shaped sectional guide rail 102 having its top opened. The moving block 101 comprises the approximately U-shaped sectional steel member 18 having its bottom opened and a molding member 19 such as thermoplastic resin, die casting, etc., filling the inside of the steel member 18; the molding member 19 defines a return passage 7, a direction reversing passage 16, and a female screw in its insert molding and at the same time defines a recess groove 21 for incorporating a nut member 20 therein. The nut member 20 is energized toward one end side in the longitudinal direction of the moving block 1 by a coned disc spring as an elastic member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various fields such as machine tools, industrial robots and precision measuring instruments.
The present invention relates to an improvement of a linear motion guide device used for guiding a movable block movably provided along a guide rail.

[0002]

2. Description of the Related Art In the field of machine tools, industrial robots, and the like, it is essential to have a technology that allows a movable block to reciprocate in one direction. For example, in a wafer grinding machine constituting a semiconductor manufacturing apparatus, the grinding apparatus is movable along a track axis provided in a horizontal direction, and rough grinding is performed at a predetermined position on the track axis to perform other grinding. It is configured to perform finish grinding at a predetermined position. As a device for making the grinding device reciprocally movable in one direction as described above, a linear motion guide device with a feed screw as shown in FIG. 7, for example, has been widely used.

The basic structure and operation of a conventional linear motion guide device with a feed screw will be described below based on the structure shown in FIG. The illustrated linear motion guide device with a feed screw is provided with a guide rail 102 having a substantially U-shaped cross section that opens upward. Further, the guide rail 10
2, a plurality of balls (steel balls) 103, 103 movably supporting the moving block 101 along the guide rail 102, and the moving block 101 with the moving of the moving block 101. A plurality of infinite circulation paths 10 for circulating a large number of balls 103, 103
8, a female screw 109 formed in a substantially central portion in the width direction of the moving block 101 so as to penetrate the moving block 101 in a longitudinal direction thereof, and a male screw 110 screwed to the female screw 109 are engraved. And the moving block 101
And a feed screw 104 for guiding the movement.

The main body 1 constituting the moving block 101
The pair of side walls 112 of the pair 13 and the pair of side walls 106 of the guide rail 102 have inner rolling surfaces 112a and 112a and outer rolling surfaces 10a, respectively.
6a and 106a are formed. By these outer and inner rolling surfaces 106a, 112a facing each other,
A load orbital path 114 that forms an endless circulation path 108 through which the balls 103 and 103 circulate is configured. The main body 1
13, a through-hole is formed, and this through-hole serves as a return passage that forms the endless circulation path 108 together with the load track path 114. Further, the main body 113 has the inner rolling surfaces 112a, 112a and the inner rolling surfaces 112a, 112a.
A semicircle-shaped turning path inner peripheral portion that is continuous with the return path corresponding to 2a is formed. The moving block 101
The side covers 105, 105 having the same vertical sectional shape as the vertical sectional shape of the main body 113, and have a direction change path outer peripheral portion formed on an inner surface thereof. The outer peripheral portion of the turning path forms a turning path together with the inner peripheral portion of the turning path. The load track paths 114, 114, the return path, and the direction change path constitute an endless circulation path 108 through which the balls 103, 103 circulate.

A female screw 109 formed at the center of the moving block 101 in the width direction has a feed screw 1 as shown in the figure.
04 is screwed. Therefore, by appropriately rotating the feed screw 104, the moving block 101 screwed to the feed screw 104 moves by a distance corresponding to the rotation amount of the feed screw 104. At this time, the balls 103, 1
03 circulates through the infinite circulation path 108 with the movement of the moving block 101. Among the balls 103, 103, the ball 1 located on the load orbit paths 114, 114
Numerals 03 and 103 support the moving block 101 movably with respect to the guide rail 102. Other balls 10
3 and 103 are located on the direction change path and the return path, move with the movement of the moving block 101, and support the moving block 101 again on the load track paths 114 and 114. As described above, since the large number of balls 103, 103 support the moving block 101 while circulating through the endless circulation paths 108, 108, the moving block 101 moves smoothly along the guide rail 102.

[0006] One end of the feed screw 104 is connected to a drive source such as an electric motor (not shown), and the feed screw 104 is rotated by operating the drive source. Therefore, by operating the driving source for an appropriate time, the feed screw 104 can be rotated by an appropriate amount, and the moving block 101 can be moved by a distance corresponding to the amount of rotation of the feed screw 104. In practice,
By adopting a servomotor as the drive source, or providing a controller for controlling the rotation amount and the rotation direction of the drive source, the moving block 101 is moved in a suitable direction by a desired distance and stopped. Make up.

[0007]

However, the above-described conventional linear motion guide device with a feed screw has the following problems to be solved. That is, when the female screw 109 and the male screw 110 of the feed screw 104 are screwed together due to an unavoidable manufacturing error, for example, as shown in FIG. Gaps 117 and 117 are generated between them. The gaps 117 and 117 allow relative movement between the feed screw 104 and the moving block 101 for an interval of the gap 117 (so-called,
Backlash). In other words, the moving block 10
In some cases, the stop position 1 may be shifted up to the distance L corresponding to the interval of the gap 117. In order to minimize such backlash as much as possible, for example,
It is conceivable to reduce the size of the cutting process as much as possible and perform the joining process many times (so-called actual joining process). However, such a physical alignment process is inferior in manufacturing efficiency, and it is impossible to completely eliminate the axial gap between the male screw 110 and the female screw 109. As a result, when a conventional linear motion guide device with a feed screw is attached to a cutting device or the like, a work placed on a mounting table fixed to the moving block 101 is subjected to a pressing force by a cutting tool or the like. In this case, the gap 117 is displaced by the distance L, and a desired portion cannot be processed.
When the return movement is performed after the movement block 101 moves in the forward path, the return movement is started after the feed screw 104 is fed in the forward direction by the distance L. Therefore, a time lag occurs in the movement of the moving block 101, and the feed screw 104
Can not move according to the drive control of.

In order to solve the above-mentioned inconvenience, for example, a technique of employing a ball screw and applying preloads in opposite directions in the axial direction with two nuts (a so-called double nut system) is considered. Used in practice. However, this technique has disadvantages that the manufacturing cost is increased and noise is generated due to ball circulation.

On the other hand, a sliding screw (see FIG.
A technique that employs the feed nut described in FIG.
No. 9 discloses this. According to the technique disclosed in this publication, as shown in FIG. 9, a female screw body 129 made of die-cast metal or synthetic resin and having a large-diameter portion 128 formed at a central portion in an axial direction of an outer peripheral surface thereof is provided on a moving block 101. Provided. Further, a portion corresponding to the length of the large diameter portion 128 on the inner peripheral surface of the female screw body 129 is provided with an annular cutout portion 130.
Is formed. Then, the first female screw portion 132 and the second female screw portion 133 are engraved with the annular cut portion 130 as a boundary. First female thread 132 and second female thread 13
3 are located on the same straight line with the same screws.
Further, a phase shift is provided between the first and second female screw portions 132 and 133. With this configuration, the axial gap when the feed screw 104 is screwed into the female screw body 129 is reduced. As a result, it is possible to improve the stop position accuracy of the moving block 101.

However, in the case of the above-described second example of the conventional structure, the first and second female screw portions 132 and 133 are utilized by utilizing the contraction of the large diameter portion 128 formed at the center of the female screw body 129. And the external thread 110 of the feed screw 104
It is considered that each tooth of abuts with each other. However, since the large-diameter portion 130 does not contract freely, it is difficult to obtain a desired amount of contraction that is sufficient to bring the teeth into contact with each other in order to stop the moving block 101 with high accuracy. As a result, similarly to the above-described conventional structure, it is not possible to obtain a stop position accuracy satisfactory to the user.

[0011] The linear motion guide device with a feed screw according to the present invention has been devised in view of the above-described circumstances.
It is an object of the present invention to provide a linear motion guide device with a feed screw in which the moving block can be accurately stopped at a desired position.

[0012]

According to a first aspect of the present invention, there is provided a linear motion guide device with a feed screw.
A guide rail having a substantially U-shaped cross section with an upper opening, a moving block provided inside the guide rail, a number of rolling elements movably supporting the moving block along the guide rail, A plurality of infinite circulation paths for circulating the plurality of rolling elements along with the movement, and a substantially central portion in the width direction of the movement block are formed in a state penetrating the length of the movement block. Female thread,
And a feed screw for engraving a male screw to be screwed into the female screw portion and guiding the movement of the moving block. The infinite circulation path includes an outer rolling surface formed on an inner surface of each of a pair of side walls of the guide rail and an inner rolling surface formed on an outer surface of each of a pair of side walls of the moving block. It has a load path, a return path penetrating the moving block in the length direction thereof, and a direction change path connecting the return path and the load path.

Particularly, in the linear motion guide device with a feed screw according to the first aspect, the moving block includes:
It is composed of a steel member having a substantially U-shaped cross section that opens downward, and a molded member filled inside the steel member. Further, the female screw portion includes a female screw engraved on the molded member, a first nut member provided in a first concave groove formed continuously with the female screw, and a first nut member. And an elastic member that presses the moving block toward one end in the length direction of the moving block.

In the linear motion guide device with a feed screw according to the first aspect of the present invention, when the feed screw is screwed into the female screw portion, the feed screw is connected to the female screw and the first screw. With the nut member. In other words, the feed screw is screwed into two nuts (so-called,
This has the same effect as (provided with a double nut). Moreover, the presence of the elastic member pushes the first nut member in a direction in which the teeth of the first nut member and the teeth of the female screw are in contact with each other, so that the screwing is reliably performed. For this reason, even if a gap due to an unavoidable manufacturing error exists between the female screw and the male screw formed in the feed screw that are screwed together, the moving block accurately stops at a desired stop position. That is, the accuracy of the stop position of the moving block is improved.

According to a second aspect of the present invention, instead of engraving the internal thread forming the internal thread, a second groove is formed and a second groove is formed in the second groove. May be provided. Further, claim 3
As described in the above, if the molded member is insert-molded into the steel member, and at the time of this insert molding, the constituent parts formed on the molded member are formed, the number of manufacturing steps can be reduced, and the manufacturing cost can be reduced. It can contribute to reduction. Further, as described in claim 4, it is also possible to adopt a so-called ball connected body in which the plurality of rolling elements are steel balls and are connected by a holding member so as to freely roll. Further, as described in claim 5, a nut member (first nut member,
Further, a through hole for attaching and detaching the second nut member) may be provided. By providing such a through hole,
The replacement and inspection of the nut member can be performed while the moving block is mounted on the guide rail. For this reason, it is possible to quickly and easily perform inspection work and replacement work of the nut member.

[0016]

1 to 4 show a first embodiment of the present invention. It should be noted that the present invention is applicable to the gaps 117 and 11 generated between the feed screw 104 and the female screw portion 11.
7, the moving block 1 is characterized in that it is prevented from stopping at a position shifted from a position to be stopped. That is, it is to improve the stop position accuracy of the moving block 101. Other configurations and operations are the same as those of the conventional structure described in the above-mentioned publication. Therefore, the same parts as those of the above-mentioned conventional structure are denoted by the same reference numerals as those in FIG. 7, and the overlapping description will be omitted or simplified.

In the linear motion guide device with a feed screw according to the present embodiment, the moving block 101 is made up of a steel member 18 having a substantially U-shaped cross section opened at the bottom and a heat filled inside the steel member 18. Molding member 19 such as plastic resin, die casting of zinc alloy, die casting of aluminum alloy, etc.
And is constituted by. The molded member 19 is insert-molded into the steel member 18 and, at the time of the insert molding, the return passages 7 and 7, the direction change passages 16 and 16, and the female screw 1 are formed.
09, a first groove 21 for incorporating the first nut member 20 is formed. In this way, the number of manufacturing steps can be reduced, which can contribute to a reduction in manufacturing cost. The insert molding is a molding method in which a cavity is formed between a member to be integrally molded and a mold, and the cavity is filled with a molding material.

The female screw portion 11 is connected to the synthetic resin member 1.
9, a first nut member 20 provided in a first groove 21 formed continuously with the female screw 109, and the first nut member 20 is connected to the moving block. 1 and a disc spring 22 that is pressed toward one end (the right end in FIG. 1) in the length direction (the left-right direction in FIG. 1 and the front and back directions in FIGS. 2 and 3). The disc spring 22 is an elastic member described in the claims. As the elastic member, in addition to the disc spring 22, the first nut member 20 such as a coil spring is elastically pressed,
Any material that can be supported in the first groove 21 can be adopted. The inner peripheral surface of the first nut member 20 and the first groove 21 into which the first nut portion 20 is fitted are formed in a rectangular shape. This is to prevent the rotation of the first nut member 20.

Further, in the present embodiment, balls (steel balls) 103, 103 are employed as the above-mentioned plurality of rolling elements, and the rolling members are connected freely by holding members 23.
A so-called ball connector 24 is employed. If such a ball connector 24 is employed, the adjacent balls 10
Since the distance between the balls 3 and 103 is kept constant, the balls 103 and 103 move smoothly, and as a result, the movement of the moving block 101 becomes smooth. Further, since the contact between the balls 103, 103 and the like are prevented, the generation of flaws and noise due to this can be prevented, and the smooth movement of the moving block 101 and the life of the entire apparatus can be improved. In FIG. 1, reference numeral 27 denotes a spacer for bringing one end of the disc spring 22 into contact.

In the linear motion guide device with a feed screw according to the present embodiment configured as described above, the basic operation related to the movement and stop of the moving block is the same as that described in the above-mentioned publication. . In particular, in the linear motion guide device with a feed screw according to the present embodiment, the feed screw 104
Is screwed into the female screw portion 11, the male screw 110 of the feed screw 104 is screwed into the female screw 109 and the female screw 9 a engraved on the first nut member 20. In other words, the feed screw 104 has the same effect as providing a so-called double nut. That is, the female screw 10
According to 9 and 9a, for the external thread 10 of the feed screw 104,
Since the preloads are applied in the opposite directions to each other, the contact state between the screws is as shown in FIG. As a result, the male screw 110
Relative movement (backlash) with respect to the female screws 109 and 9a is slightly suppressed.

The disc spring 22 not only supports the first nut member 20 in the first groove 21 but also presses the first nut member 20. For this reason, when the disc spring 22 is mounted as shown in FIG.
2, the female screw 9a and the male screw 10 come into contact with each other, for example, as shown in FIG.
The displacement of the moving block 1 from the stop position is suppressed irrespective of the presence of. In addition, the presence of the disc spring 22 increases the contact pressure between the female screw 9a of the first nut member 20 and the male screw 10 of the feed screw 4, thereby preventing the moving block 1 from shifting and moving. As a result, the moving block 1
Can accurately stop at the stop position.

Further, in the case of this embodiment, the guide rail 1
The through hole 1 for attaching and detaching the first nut member 20 constituting the female screw portion 11 is provided on the bottom surface of the female screw portion 02. By providing such a through hole 1, replacement and inspection of the first nut member 20 can be performed while the moving block 101 is mounted on the guide rail 102. However, the screw engagement between the moving block 101 and the feed screw 104 needs to be completely removed. In the case of the structure of the present embodiment, the above-mentioned replacement or inspection is performed by moving the moving block 101 to the guide rail 10.
The ball 103 can be removed from the guide rail 102 when the nut is replaced or the like as in the conventional structure because the ball 103 can fall off while passing through the through-hole 1 while being mounted on Alternatively, there is no need to take measures to prevent this dropout. Therefore, the inspection work and the replacement work of the first nut member 20 can be performed quickly and easily.

FIG. 5 shows a second embodiment of the present invention. The structure of the present embodiment is a female screw 109 (FIG. 1, FIG.
Instead of engraving (see FIG. 2), a second groove 26 is formed, and a second nut member 27 is provided in the second groove 26. The second groove 2
6 is formed together with the first groove 21 and the like when the synthetic resin member 19 is insert-molded into the steel member 18 constituting the moving block 1. As described in the first embodiment, the insert molding is a molding method in which a cavity is formed between a member to be integrally molded and a mold, and the cavity is filled with a molding material.

Other configurations and operations in the second embodiment are the same as those in the first embodiment.
In this embodiment, an elastic member such as a disc spring 22 (FIGS. 2 and 5) is not mounted in the second groove 26, but the second groove 26 is provided in the second groove 26. An elastic member such as a disc spring 22 similar to the elastic member mounted in the one concave groove portion 21 may be mounted. Such a disc spring 22 is mounted on at least one of the one end side and the other end side in at least one of the concave grooves 2, 26.

Further, in the case of the embodiment according to the present invention, the first and second nut members 20, 27 can be detachably attached to the first moving block 101. Therefore, first and second nut members having different materials and the accuracy of the female screw to be engraved are prepared in advance, and the first and second nut members are appropriately adjusted according to the purpose of use of the linear motion guide device with a feed screw. Members 20, 27
Can be selected and used. Other configurations and operations are the same as those in the first embodiment.

[0026]

Since the linear motion guide device with a feed screw according to the present invention is constructed and operates as described above, the stop position of the moving block can be controlled with high precision despite being easy and inexpensive to manufacture. It becomes possible. Further, with the use of the slide screw, the purging performance is improved as compared with the case where the ball screw is used. That is, claim 1
In the invention described in each of claims 2 and 3, when the feed screw is screwed into the female screw portion, the female screw and the first nut member are screwed together to apply preloads in opposite directions to each other. Has the same effect as providing a so-called double nut. In addition, since the elastic member that presses the first nut member makes sure that the female screw of the first nut member and the male screw of the feed screw are in contact with each other, the moving block accurately stops at the stop position. It becomes possible. As a result, it plays a large role in high-precision machining and the like in various machining devices and the like using a linear motion guide device with a feed screw. Further, the use of the slide screw does not generate noise due to the circulation of the ball as in the case of using the ball screw, thereby improving quietness.

According to the third aspect of the present invention,
At the time of insert molding, it is possible to form the constituent parts formed on the molded member, so that the number of manufacturing steps can be reduced, which can contribute to a reduction in manufacturing cost. Further, in the invention described in claim 4, smooth rolling of the ball, which is a rolling element, and prevention of falling of the ball at the time of assembly or maintenance and inspection can be achieved. Further, in the invention described in claim 5, the nut member (the first nut member, and further the second nut member) constituting the female screw portion is provided through a through hole provided in the bottom surface of the guide rail. Since it is detachable, the replacement and inspection of the nut member can be performed while the moving block is mounted on the guide rail, and the inspection and replacement work of the nut member can be performed quickly and easily. Great practical effect.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional plan view of the same main part.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a front view showing only a moving block.

FIG. 5 is a cross-sectional view for explaining an effect of the first nut member, showing a screwed state of a feed screw and a female screw formed on a moving block.

FIG. 6 is a cross-sectional plan view of a main part showing a second embodiment of the present invention.

FIG. 7 is a perspective view showing an example of a conventional structure of a linear motion guide device with a feed screw.

FIG. 8 is a cross-sectional view showing a screwed state of a feed screw and a female screw formed on a moving block.

FIG. 9 is a cross-sectional plan view showing a second example of the conventional structure of the linear motion guide device with a feed screw.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Through-hole 101 Moving block 102 Guide rail 103 Ball 104 Feed screw 106, 112 Side wall 106a Outer rolling path 7 Return path 108 Infinite circulation path 109, 9a Female screw 110 Male screw 11 Female screw part 112a Inner rolling path 114 Load track path 16 Direction path Reference Signs List 18 steel member 19 synthetic resin member 20 first nut member 21 first concave groove portion 22 disc spring 23 holding member 25 second concave groove portion 26 second nut member

Claims (5)

[Claims] 1. A guide rail having a substantially U-shaped cross section with an open upper part, a moving block provided inside the guide rail, and a number of rolling elements for movably supporting the moving block along the guide rail. A plurality of infinite circulation paths through which the plurality of rolling elements circulate in accordance with the movement of the moving block, and a substantially central portion in the width direction of the moving block penetrating the moving block in the longitudinal direction thereof. A female screw portion formed in a state, a male screw threaded with the female screw portion is engraved, and a feed screw that guides the movement of the moving block, the infinite circulation path includes a pair of A load orbital path comprising an outer rolling surface formed on each inner side surface of the side wall and an inner rolling surface formed on each outer surface of a pair of side walls of the moving block, and a longitudinal direction of the moving block; A linear motion guide device with a feed screw, comprising: return passages provided in a state penetrating the return passage; and a direction change path continuous with the return passages and the load track path. The block is composed of a steel member having a substantially U-shaped cross section with a lower opening, and a molded member filled inside the steel member. The female screw portion is engraved on the molded member. Female screw,
A first nut member formed in a first concave groove portion formed downwardly and formed continuously with the female screw, and the first nut member is directed toward one longitudinal end of the moving block. A linear motion guide device with a feed screw, comprising: a pressing elastic member. 2. A method according to claim 1, further comprising: forming a second groove having a downward opening, and providing a second nut member in the second groove instead of engraving the female screw constituting the female screw. The linear motion guide device with a feed screw according to claim 1, wherein: 3. The molding member is formed by insert molding the steel member.
The linear motion guide device with a feed screw according to any one of claims 1 to 2, wherein constituent parts formed on the molding member are formed. 4. The plurality of rolling elements are steel balls, and
The linear motion guide device with a feed screw according to any one of claims 1 to 3, wherein rolling is freely connected by a holding member. 5. The feed according to claim 1, wherein a through hole for attaching and detaching a nut member constituting the female screw portion is provided on a bottom surface of the guide rail. Linear motion guide device with screw.