JP2000257631A - Linear motion guide device with feed screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform highly accurate control of a stop position of a moving block regardless of a clearance between theeth in a part where a feed screw of a linear motion guide device with a feed screw threadedly engages with an internal thread provided in the moving block. SOLUTION: A moving block 1 is provided with a steel-made member 18 of almost U-shaped section opening the downward and synthetic resin member 19 with which inside this steel-made member 18 is charged. An internal thread part 11 formed in the moving block 1 for screwing a feed screw is provided with an internal thread 9 engraved in the synthetic resin member 19 and a first nut member 20 provided in a first recessed groove part 21 formed successively to this internal thread 9. In addition, a plate spring 22 pressing this first nut member 20 toward a lengthwise direction one end side of the moving block 1 is provided. In this way, the first nut member 20 is supported mountably/ demountably in the first recessed groove part 21.

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 described above, a linear motion guide device with a feed screw has been widely used as a device for reciprocating the grinding device in one direction.

FIG. 6 shows a linear motion guide device with a feed screw described in Japanese Patent Application Laid-Open No. 9-14379.
Hereinafter, based on the configuration shown in FIG. 6, the basic configuration and operation of a conventional linear motion guide device with a feed screw will be described. The illustrated linear motion guide device with a feed screw is provided with a guide rail 2 having a substantially U-shaped cross section that opens upward. Further, a moving block 1 provided inside the guide rail 2 and a large number of balls (steel balls) for movably supporting the moving block 1 along the guide rail 2.
3, 3 and a plurality of infinite circulation paths 8 for circulating the large number of balls 3, 3 with the movement of the moving block 1,
8, a female screw 9 formed in a substantially central portion in the width direction of the moving block 1 so as to penetrate the moving block 1 in a longitudinal direction thereof, and a male screw 10 screwed to the female screw 9 are engraved. And a feed screw 4 for guiding the movement of the moving block 1.

The pair of side walls 12 and 12 of the main body 13 constituting the moving block 1 and the pair of side walls 6 and 6 of the guide rail 2 have inner rolling surfaces 12a and 12a, respectively. Outer rolling surfaces 6a, 6a are formed. Outer and inner rolling surfaces 6 facing each other
The load track path 14 on which the balls 3 and 3 roll is constituted by a and 12a. The body 13 has a through hole 1.
5, 15 are formed, and these through holes 15, 15 are used as return passages 7, 7. Further, the main body 13 has the inner rolling surfaces 12a, 12a and the inner rolling surfaces 12a, 12a.
The return passages 7 and 7 corresponding to 2a form a semicircular turning path inner peripheral portion that is continuous. The side lids 5, 5 constituting the moving block 1 have the same vertical cross-sectional shape as the vertical cross-sectional shape of the main body 13, and have a direction changing path outer peripheral portion formed on the inner surface thereof. The outer periphery of the direction change path forms the direction change paths 16 and 16 together with the inner circumference of the direction change path. The load track paths 14 and 14 and the return paths 7 and 7
And the direction change paths 16, 16, the ball 3,
An infinite circulation path 8, 8 through which 3 circulates is configured.

[0005] At the center in the width direction of the moving block 1 constituted by the main body 13 and the pair of side lids 5, 5, a female screw 9 penetrating the moving block 1 is formed. The feed screw 4 as shown in FIG. 6 is screwed to the female screw 9. Therefore, by appropriately rotating the feed screw 4, the moving block 1 screwed to the feed screw 4 moves by a distance corresponding to the rotation amount of the feed screw 4.
At this time, the balls 3 circulate in the infinite circulation paths 8 with the movement of the moving block 1. These balls 3,
Of the three, the balls 3, 3 positioned on the load track paths 14, 14 support the moving block 1 movably with respect to the guide rail 2. The other balls 3, 3 are located in the direction change paths 16, 16 and the return paths 7, 7, and move with the movement of the moving block 1, and are again positioned on the load track paths 14, 14 to move the moving block 1 again. To support. As mentioned above,
Since a large number of balls 3, 3 support the moving block 1 while circulating through the endless circulation paths 8, 8, the moving block 1
Moves smoothly along the guide rail 2.

[0006] One end of the feed screw 4 is connected to a drive source such as a motor (not shown), and the feed screw 4 is rotated by operating the drive source. Therefore, by operating the drive source for an appropriate time, the feed screw 4 is rotated by an appropriate amount,
The moving block 1 can be moved by a distance corresponding to the amount of rotation of the moving block 1. In an actual case, the moving block 1 is moved in an appropriate direction by a desired distance by adopting a servomotor as the driving source or providing a controller for controlling the rotation amount and the rotating direction of the driving source. It is configured to stop.

[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 9 and the male screw 10 of the feed screw 4 are screwed together due to an inevitable manufacturing error, for example, as shown in FIG. Gaps 17, 17 are generated between them. The gaps 17 allow relative movement between the feed screw 4 and the moving block 1 by the distance of the gap 17. In other words, the stop position of the moving block 1 may be shifted up to the distance L of the gap 17.

In order to solve the above-mentioned inconvenience, the invention shown in FIG. 8 is described in Japanese Patent Application Laid-Open No. 9-14379. In the structure of the second conventional example shown in FIG. 8, a female screw 29 made of die-cast metal or synthetic resin and having a large-diameter portion 28 formed at the axial center of the outer peripheral surface is provided on the moving block 1. ing. Further, an annular cutout portion 30 is formed in a portion corresponding to the length of the large diameter portion 28 on the inner peripheral surface of the female screw body 29. Then, the first female screw part 32 and the second female screw part 33 are engraved with the annular cut part 30 as a boundary. The first female screw part 32 and the second female screw part 33 are located in the same straight line with the same screw. Further, a phase shift is provided between the first and second female screw portions 32 and 33. With this configuration, the axial gap when the feed screw 4 is screwed into the female screw body 29 is reduced. As a result, it is possible to improve the stop position accuracy of the moving block 1.

However, in the case of the structure of the second conventional example described above, the first and second female screw portions 32, 32 are formed by utilizing the shrinkage of the large diameter portion 28 formed at the center of the female screw body 29. It is considered that the teeth of the male screw 33 and the male screw 10 of the feed screw 4 are in contact with each other. However, since the large diameter portion 30 does not shrink freely,
It is difficult to obtain a desired amount of shrinkage that is sufficient to bring the teeth into contact with each other in order to stop the moving block 1 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.

A 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.

[0011]

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.

In particular, 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.

[0013] In the linear motion guide device with the feed screw according to the first aspect, 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 forming the female screw constituting the female screw portion, a second concave groove portion is formed, and a second concave groove portion is formed in the second concave groove portion. 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.

[0015]

1 to 4 show a first embodiment of the present invention. The present invention has a feature in a structure for preventing the moving block 1 from stopping at a position shifted from a position to be stopped based on the gaps 17 formed between the feed screw 4 and the female screw portion 11. ing. That is, it is to improve the stop position accuracy of the moving block 1. Other configurations and operations are the same as those of the second conventional example described in the above-mentioned publication. Therefore, the duplicate description of the same parts as those of the above-mentioned conventional structure will be omitted or simplified, and the following description will focus on the features of the present invention.

In the linear motion guide device with a feed screw according to the present embodiment, the moving block 1 is made up of a steel member 18 having a substantially U-shaped cross section which opens downward, and a heat filled inside the steel member 18. And a molded member 19 such as a plastic resin, a die cast of a zinc alloy, and a die cast of an aluminum alloy. The formed member 19 is made of the steel member 1 described above.
8, and at the time of the insert molding, first concave grooves 21 for incorporating the return passages 7, 7, the direction changing passages 16, 16, the female screw 9, and the first nut member 20 are 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 9, and the first nut member 20 is connected to the moving block. 1 in the longitudinal direction (the left-right direction in FIG. 1, the front-back direction in FIGS. 2 and 3) and a leaf spring 22 that is pressed toward one end (the right end in FIG. 1). The leaf spring 22 is an elastic member described in the claims. As the elastic member, other than the above-described leaf spring 22, a coil spring or the like that can elastically press the first nut member 20 and support the first nut member 20 in the first concave groove portion 23 can be adopted. still,
The first nut member 20 and the first nut portion 20
The inner peripheral surface shape of the first concave groove portion 21 in which is fitted is 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) 3, 3 are employed as the plurality of rolling elements,
A so-called ball connector 24 is used, which is freely connected to rolling by a holding member 23. If such a ball connector 24 is employed, the distance between the adjacent balls 3, 3 is kept constant, so that the balls 3, 3 move smoothly, and as a result, the movement of the moving block 1 Becomes smoother. Further, since contact between the balls 3, 3 and the like are prevented, the generation of scratches and noise due to this can be prevented,
Along with the smooth movement of the moving block 1, the life of the entire apparatus can be improved. In FIG. 1, reference numeral 27 denotes a spacer for bringing one end of the leaf 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 relating 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 this embodiment, when the feed screw 4 is screwed into the female screw portion 11, the male screw 1 of the feed screw 4
0 is screwed into the female screw 9 and the first nut member 20. In other words, the feed screw 4 has the same effect as providing a so-called double nut. In addition, the leaf spring 22 not only supports the first nut member 20 in the first groove 21, but also supports the first nut member 20.
Press. For this reason, when the leaf spring 22 is mounted as shown in the figure, the contact between the female screw 9a and the male screw 10 becomes as shown in FIG. The displacement of the moving block 1 from the stop position is suppressed irrespective of the presence of. Further, due to the presence of the leaf spring 22, the contact pressure between the female screw 9a of the first nut member 20 and the male screw 10 of the feed screw 4 is increased,
The moving block 1 is prevented from shifting. As a result, the moving block 1 can accurately stop at the stop position.

FIG. 5 shows a second embodiment of the present invention. The structure of the present embodiment is similar to that of the female screw 9 (FIGS. 1 and 4) that constitutes the female screw portion 11 according to the first embodiment.
), A second groove 26 is formed, and a second nut member 27 is provided in the second groove 26. The second groove 26
When the synthetic resin member 19 is insert-molded into the steel member 18 constituting the moving block 1, the first groove 2
Formed together with 1 etc. 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 structures and operations in the second embodiment are the same as those in the first embodiment.
In this embodiment, an elastic member such as a leaf spring is not mounted in the second groove 26, but is mounted in the first groove 21 in the second groove 26. An elastic member such as a leaf spring 22 similar to the above may be mounted. Such a leaf spring 22 includes at least one of the concave groove portions 21,
26, is mounted on at least one of one end and the other end thereof.

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 1. 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. The members 20, 27 can be selected and used.

[0023]

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. That is,
In the invention described in claim 1 and claim 2, when the feed screw is screwed into the female screw portion, the screw is screwed into the female screw and the first nut member to provide a so-called double nut. Has the effect of 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.

In the invention described in claim 3,
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. Furthermore, in the invention described in claim 4, smooth rolling of the ball as the rolling element and prevention of the ball from falling off at the time of assembling or maintenance and inspection can be achieved, and the practical effect is large.

[Brief description of the drawings]

FIG. 1 is a cross-sectional plan view of a main part showing a first embodiment of the present invention.

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

FIG. 3 is a front view showing only a moving block.

FIG. 4 is a cross-sectional view schematically illustrating a screwed state of a feed screw and a female screw formed on a moving block, for describing an effect of the first nut member.

FIG. 5 is a cross-sectional plan view of a main part showing a second embodiment of the present invention.

FIG. 6 is an exploded perspective view showing the structure of a first example of a conventional linear motion guide device with a feed screw.

FIG. 7 is a cross-sectional view schematically illustrating a screwed state of a feed screw and a female screw formed on a moving block.

FIG. 8 is a cross-sectional plan view showing the structure of a second conventional example of a linear motion guide device with a feed screw.

[Explanation of symbols]

 1 Moving block 2 Guide rail 4 Feed screw 7 Return path 8 Infinite circulation path 9, 9a Female screw 10 Male screw 11 Female screw part 14 Load track path 16 Direction changing path 18 Steel member 19 Synthetic resin member 20 First nut member 21 First Groove portion 22 leaf spring 25 second concave groove portion 26 second nut member

Claims (4)

[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 provided in a first concave groove portion formed continuously with the female screw, and an elastic member for pressing the first nut member toward one end of the moving block in the length direction. And a linear motion guide device with a feed screw. 2. A method according to claim 1, wherein a second groove is formed instead of engraving a female screw constituting the female screw, and a second nut member is provided in the second groove. 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.