JPH0649963Y2 - Table unit with integrated ball screw, linear guide and mounting base - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a table unit in which a ball screw, a linear guide, and a mounting base are integrally formed.

[Conventional technology]

An example of a conventional device in which a ball screw and a linear guide device are combined is disclosed in Japanese Utility Model Laid-Open No. 61-61362.

This is a screw shaft of a feed screw having a spiral groove on the outer surface, a linear guide rail arranged in parallel to the screw shaft, and a linear guide rail which is loosely fitted in the linear guide rail so as to be movable in the axial direction and is attached to the screw shaft. The linear guide means (slider) has a built-in nut portion to be screwed.

By combining a linear guide device and a ball screw in this way, for example, a table of a machine tool is not simply guided linearly, but a drive device can be used to actively drive / stop and control the position. A compact feed unit is formed. Also, since the ball screw nut and the slider of the linear guide device can be machined with the same reference surface, they are highly accurate and do not require a great number of man-hours for assembly and adjustment, so they can be used in robots, conveyors, and various other applications. There is an advantage that the range of application of the linear guide device can be expanded.

[Problems to be solved by the device]

However, the conventional compact feed unit has a level between the center of the screw shaft and the center line of the ball row in the ball rolling groove of the linear guide device when the screw shaft of the ball screw and the linear guide device are combined. There is a difference.
Therefore, when the slider advances in the axial direction due to the rotation of the screw shaft, the resistance of the row of balls moving in the opposite direction in the ball rolling groove acts as a couple force and the slider is twisted. There was a problem.

An object of the present invention is to solve the above-mentioned conventional problems by specifying the arrangement of the screw shaft and the ball row in the ball rolling groove of the linear guide device.

[Means for Solving the Problems]

The present invention that achieves the above object has a base portion having attachment means and side wall portions at both ends of the base portion, and has a U-shaped cross section. The side surfaces of the both side wall portions face each other in the axial direction. And a guide rail formed of one member in which each of the ball rolling grooves is formed symmetrically with two threads, and a ball screw groove on the outer peripheral surface of the guide rail, which is arranged in a recess formed between both side wall portions of the guide rail. The ball screw shaft is mounted at the end of the guide rail and the ball screw shaft whose axis is parallel to the ball rolling groove at the center point position where the ball rolling groove is viewed vertically and horizontally, and the ball screw shaft is rotated. A support bearing unit that freely supports the ball rolling groove in the axial direction and a side surface formed over the entire length of the ball rolling groove facing the ball rolling groove of the guide rail is provided on both sides. With a corresponding linear ball passage A slider body comprising a member having a through hole formed in its wall thickness and having a hole for inserting the ball screw shaft formed therein, and having a ball screw shaft facing the ball screw shaft of the ball screw shaft formed on the inner surface of the hole. And an end cap that is fixed to both axial end surfaces of the slider body, has a curved ball passage that connects the ball rolling groove of the slider body and the through hole, and has a hole that inserts the ball screw shaft. A first ball group rotatably fitted between a ball rolling groove of the slider body and a ball rolling groove of the guide rail facing the ball rolling groove; and a ball screw groove of the slider body. A second ball group that is rotatably fitted between the ball screw groove of the ball screw shaft and the ball screw groove that opposes this is provided.

[Action]

When the ball screw shaft is rotated, the nut responds to this and the slider moves in the axial direction while being guided by the guide rail. At this time, the propulsive force of the slider and the resistance force of the row of balls moving in the ball rolling groove in the direction opposite to the traveling direction of the slider do not become a couple. Therefore, the slider is not twisted.

Since both the guide rail and the slider are units made of one member, the user does not need to assemble or adjust the accuracy of the operation, and the handling is facilitated.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the drawings, the same or corresponding parts are designated by the same reference numerals. 1 to 4 show a first embodiment of the present invention, in which a guide rail 1 has a substantially U-shaped cross section, and both side wall portions 1a and 1b are raised from a bottom base portion 1c. Is a member made of one member which has two parallel upper and lower ball rolling grooves 2 which extend in the axial direction and which are symmetrical to each other. The guide rail 1 serves as a mounting base for the feed unit device. Bearing plates 3 and 4 are attached by screws to both ends of the guide rail 1 in the longitudinal direction. Reference numeral 5 denotes a screw hole provided on the end surface of the rail for fixing the screw. A ball bearing 6 is attached to the bearing plate 3, and a ball bearing 8 is double attached to the bearing plate 4 via a support bearing unit 7. A ball screw shaft 9 of a ball screw, which is supported by these bearings 6 and 8 and has a ball screw groove on its outer peripheral surface, has a ball rolling groove 2 at the center of the width of a recess formed between both side wall portions of the guide rail 1. The ball screw shaft 9 is supported by the support bearing unit 7 so as to be rotatable and immovable in the axial direction.

The ball screw of this embodiment is a so-called tube type,
The nut portion 10 is screwed onto the ball screw shaft 9 through a large number of steel balls B (second ball group), and the steel balls B are attached to the ball screw shaft 9 along the ball tube 10A provided on the nut portion 10. It is a structure that moves diagonally over the land. In addition,
The ball tube 10A is fixed by making a hole in the upper surface of the slider 11 described below and inserting the resin, and then pouring resin into the hole. If you need to remove the ball tube 10A,
Make a hole in the resin of the hole and bite the tool under the ball tube to pull it out.

Reference numeral 11 denotes a slider in which the nut portion 10 is formed as a single member and is inserted into the ball screw shaft 9, and both left and right edges of the slider are extended downward to form a sleeve portion 12. The inner diameter of the slider 11 between the sleeves 12 is formed slightly larger than the lateral width of the guide rail 1, and the slider 11 is laid across the guide rail 1 so as to cover the upward opening of the U-shaped rail. Then, on the slider body 11A of the slider 11, both left and right sleeve parts 1
A ball rolling groove 14 is formed over the entire length of the inner side surface of the guide rail 2 so as to face the ball rolling groove 2 of the guide rail, and a ball formed of a linear through hole parallel to the ball rolling groove 14. A passage 15 is formed within the wall thickness of the sleeve portion 12.
Further, an end cap 16 attached to the front and rear end surfaces of the slider body 11A and provided with a hole through which the ball screw shaft 9 is inserted.
A semi-doughnut-shaped curved ball passage 17 that connects the ball passage 15 and the ball rolling groove 14 is formed therein. As a result, the ball rolling grooves 2 and 14 and the ball passage 15 which face each other.
And a curved ball passage 17 form an infinite ball circulation path, and a large number of balls 18 are formed in this infinite ball circulation path.
The (first ball group) is rotatably mounted and held by a wire-type retainer 19 for preventing falling (see FIG. 4).

Thus, the central axis O of the ball screw shaft 9 is horizontally centered between two upper and lower rows of balls consisting of balls 15 rolling in the ball rolling grooves 2 and 14 of the guide rail 1 and the slider body 11A facing each other. It is assumed to be a horizontal plane including the centerline X connecting to. Therefore, the center of the ball screw shaft 9 is the four ball rolling grooves 2,14.
This is the position where you can see symmetric vertically and horizontally.

Further, the sleeve portion 12 of the slider body 11A is extended to some extent upward to provide a transported object mounting base 20, which is provided with a screw hole 21 for a transported object mounting screw. That is,
The vertical load applied to the slider main body 11A by the not-shown conveyed product is directly applied to the sleeve portion 12 located immediately below the conveyed product mounting base 20.

Reference numeral 22 is a travel stopper fixed to the end cap 16 with a set screw 23.
It is configured to have a rubber material that absorbs the impact when it comes into contact with the, and functions as a cushion. 24 is a screw hole of the set screw 23, and 25 is a grease nipple. The bearing plate 3 is provided with an escape hole 30 for the grease nipple 25 when the slider 11 contacts.

Reference numeral 26 is a mounting means provided on the guide rail 1, and is a bolt mounting hole for fixing the guide rail 1 to a base or the like. A labyrinth seal 27 seals the thread groove of the ball screw shaft 9.

Next, the operation will be described.

When the ball screw shaft 9 is rotated by the driving of a servo motor (not shown), the nut portion 10 responds to the shaft rotation, and the slider 11 moves in the axial direction while being guided by the guide rail 1.
The movement of the slider 11 is performed by moving the nut portion 10 and the ball screw shaft 9
The rolling of the hard sphere B interposed between the guide rail 1 and the slider 11 and the rolling of the ball 18 interposed between the ball rolling grooves 2 and 14 of the slider 11 make it extremely smooth. Done.

In this case, the central axis O of the ball screw shaft 9 and the central line X of the ball row in the nozzles 2 and 14 of the guide rail 1 and the slider 11
Are the same, and there is no level difference between the two as in the conventional case. Therefore, the driving force when the slider 11 advances in the axial direction by the rotation of the ball screw shaft 9 and the guide rail 1
The resistance of the row of balls moving in the ball rolling grooves 2 and 14 of the slider 11 and the slider 11 do not act as a couple, and therefore the disadvantage that the slider 11 is twisted cannot occur.

Further, the load F applied by the transported object attached to the slider 11 straddled over the guide rail 1 is downwardly applied to the transported object mounting base 20 arranged directly above the sleeve portions 12 of the slider, and therefore the load F is caused by the load F. The bending deformation of the slider 11 hardly occurs. By the way, in the conventional case, the load F applied to the central portion of the slider having a U-shaped cross section, which is laid across the guide rail, is
It does not act directly below the slider sleeve, and as a result the slider sleeve opens outward and the fit between the ball and the ball rolling groove becomes loose, causing slider rolling, yawing, pitching, etc. It was easier.

Further, the guide rail 1 of this embodiment is made of one member having a U-shaped cross section instead of the conventional square cross section, and has a large groove width so that it has a large rigidity and is opposed to each other. The ball rolling grooves 2 and 14 are easily polished, are lightweight, and are easy to handle. Further, since the ball screw shaft 9 is housed in the groove and the slider 11 is attached so as to cover the groove, a dust-proof cover such as a bellows type is provided between the bearing plates 3 and 4 at both ends and the slider 11. Is also easy to install,
It is extremely effective in preventing troubles due to dust, and is suitable for a dusty environment or, conversely, for a clean room that requires no dust.

Further, the slider 11 is also H-shaped in cross section, and the weight reduction is achieved without impairing the strength.

In the second embodiment shown in FIGS. 5 and 6, the ball rolling groove 2 is formed on the inner surface 1b of the guide rail 1 having a U-shaped cross section, and the slider 11 has a square cross section. It is loosely fitted in the groove 1. Incidentally, FIG. 6 schematically shows the internal circulation system of the hard sphere B. Also in this case, the central axis O of the ball screw shaft 9, the guide rail 1 and the slider
The center lines X of the ball rows in the upper and lower ball rolling grooves 2 and 14 of 11 are the same. Guide rail 1 of this second embodiment
Has an advantage that a large-diameter grinding wheel can be used and the manufacturing becomes easy because the inter-groove size of the left and right ball rolling grooves 2 becomes large.

The present invention is not limited to the tube type ball screw, and may be a so-called top type ball screw configured to internally circulate the hard sphere along the groove of the top provided in the nut portion.

[Advantages of the Invention] As described above, according to the present invention, the base portion having the attachment means and the side wall portions at the both side ends of the base portion have a U-shaped cross section, and the side wall portions are A guide rail made of one member in which axial ball rolling grooves are symmetrically formed on each of the two opposite side surfaces is used, and the ball screw shaft is positioned at the center point where the ball rolling grooves are vertically and horizontally symmetrically viewed. An axis is arranged in parallel with the ball rolling groove, and a slider made of one member is supported by the guide rail through rolling of the ball and screwed onto the ball screw shaft through rolling of the ball. Since the unit has the structure described above, it is not necessary to adjust the parallelism of the ball rolling grooves in the axial direction formed on the guide rail and the slider in the assembly process as in the conventional case. , Some sliders It is made of material, and there is no need for the user to assemble this unit, adjust the accuracy of the operation, adjust the assembly clearance when assembling the balls, or adjust the preload.In addition, when the slider advances in the axial direction due to the rotation of the ball screw shaft. The resistance of the row of balls moving in the ball rolling groove against the propulsive force of the slider does not act as a couple and the disadvantage that the slider is twisted can be prevented, the handling is easy, and the weight and size can be reduced. The effect is obtained.

[Brief description of drawings]

1 to 4 show a first embodiment of the present invention, FIG. 1 is a side view with a part cut away, FIG. 2 is a front view with a part removed, and FIG. 3 is a partial view. Plan view, FIG. 4 is IV-I in FIG.
FIG. 5 is a sectional view taken along line V, FIG. 5 is a partial perspective view of the second embodiment of the present invention, and FIG. 6 is a sectional view taken along line VI-VI of FIG. 1 is a guide rail, 1a and 1c are side wall portions of the guide rail, a base portion, 2 is a ball rolling groove (of the guide rail), 7 is a support bearing unit, 9 is a ball screw shaft, 10 is a nut portion, 11 is a A slider, 11A is a slider body, 14 is a ball rolling groove (of the slider), 15 is a ball passage, 16 is an end cap, 17 is a curved ball passage, 18 is a first ball group, B
Is a second ball group, and 26 is a bolt mounting hole.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-58-142020 (JP, A) JP-A-62-37513 (JP, A) JP-A-62-233517 (JP, A) JP-A-59- 137616 (JP, A) JP 58-214015 (JP, A) Actual development 61-68842 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A base portion having mounting means and side wall portions at both ends of the base portion, which are U-shaped in cross section, and axially ball rolling grooves are formed on opposite side surfaces of the both side wall portions. Each 2
A guide rail made of one member that is formed symmetrically with the strip,
It has a ball screw groove on the outer peripheral surface and is arranged in a recess formed between both side wall portions of the guide rail. It is a central point position where the ball rolling groove is vertically and horizontally symmetrically seen, and the axis line is the ball rolling groove. A ball screw shaft arranged in parallel to the guide rail, a support bearing unit attached to an end portion of the guide rail for supporting the ball screw shaft rotatably and immovably in the axial direction, and a ball rolling groove of the guide rail. The ball screw shaft has opposite side surfaces formed with ball rolling grooves over the entire length on both sides, and has through-holes in the wall thickness which are linear ball passages corresponding to the ball rolling grooves. A slider body having a hole through which a ball screw groove is formed on the inner surface of the hole, the ball screw groove facing the ball screw groove of the ball screw shaft; and a slider body fixed to both axial end surfaces of the slider body. Slur An end cap having a curved ball passage for communicating the ball rolling groove of the da body with the through hole and having a hole for inserting the ball screw shaft; a ball rolling groove of the slider body and the ball rolling groove facing the ball rolling groove. Between the first ball group that is rollably fitted in the ball rolling groove of the guide rail, and between the ball screw groove of the slider body and the ball screw groove of the ball screw shaft facing the ball screw groove. A ball screw, a linear guide, and a mounting base integrated table unit, which is equipped with a second ball group that is rotatably fitted to the table.