JPS58187644A - Releasable supporting device of ball screw - Google Patents

Abstract

PURPOSE:To remarkably heighten the critical rotational speed of the ball screw and consequently enable to use the long ball screw with small diameter by a method wherein the ball screw is pivotablly pinched by an intermediate supporting device which is releasable so as not to disturb the movement of a ball nut. CONSTITUTION:When the right end of the ball nut 20 reaches the predetermined distance A during its rightward movement, a first contact segment 27 comes into contact with a first limit switch 29. Consequently, a first and a second cylinders 25 and 26 are brought into actuation so as to release the pinching of the ball screw 14 made by movable pinching bodies 23 and 24. When the left end of the ball nut 20 parts from the predetermined distance A during its further rightward movement, the contact between the first contact segment 27 and the first limit switch 29 is released. Consequently, the movable pinching bodies 23 and 24 pinch the ball screw 14 again. Accordingly, the supporting of the ball screw 14 by the intermediate supporting device 21 at the middle of supporting devices 15 and 16 is realized at all times except when the ball nut 20 approaches beyond the distance A to the intermediate supporting device 21.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ball screw support device used for moving and positioning a moving table or the like.

In machine tools, such as turret punch press machines, as a means of moving the moving table that fixes the workpiece,
Many moving mechanisms are used in which a pole nut fixed to a moving table is fitted onto a ball screw, and as the ball screw rotates, the pole nut moves in the axial direction of the ball screw, thereby moving the moving table.

As shown in Fig. 1, this ball screw 1 is rotatably supported near both ends by supports @123.4 so as not to hinder the movement of the pole nut 2. However, in order to increase the range of movement, It is necessary to increase the length l of the ball screw 1, and in order to reduce the rotational load of the motor that rotationally drives the ball screw 1, it is necessary to increase the length l of the ball screw 1. It is necessary to reduce D to reduce the moment of inertia of the ball screw 1, and for this reason, longer and smaller diameter ball screws are increasingly being used.

However, when the ball screw 1 becomes long and has a small diameter, the critical rotation speed (proportional to D/1) of the ball screw 1 becomes significantly small. Therefore, when the ball screw 1 is rotated at high speed, primary, secondary, and tertiary vibrations occur as shown in Fig. 2 (a), (b), and (c), respectively, resulting in severe noise and significant loss of movement accuracy. When the rotational speed is further increased, many problems arise, such as wear and tear of the ball screw and ball nut support.

The object of the present invention is to correct the above-mentioned drawbacks and provide a ball screw support device that does not cause the above-mentioned disadvantages even when a long, small-diameter ball screw is rotated at high speed.

For this purpose, the present invention provides an intermediate support device that releasably holds the intermediate portion of the ball screw, and supports the intermediate portion of the ball screw with the intermediate support device except when the pole nut is passing. It is characterized by reducing the apparent length and increasing the rotational critical speed, thereby eliminating the aforementioned vibrations, noise, reduction in movement accuracy, wear and tear, etc.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

3 to 5 show an embodiment of the present invention, which shows a ball screw support device for moving a movable table of a turret punch press machine.

In the figure, 11 is a table base, 12 is a movable base fixed to the movable table, and the movable base 12 is the table base 1.
It is slidably attached to a guide rail 13 fixed to the 11th surface.

Further, a ball screw 14 is provided on the table base 11 in parallel to the guide rail 13. The ball screw 14 has first and second support devices f15.1 near both ends thereof.
6, and is rotated in either forward or reverse directions by a motor 18 via gears, mechanisms 17, etc.

A bracket 19 projecting in the direction of the ball screw 14 is fixed to the movable base 12, and a pole nut 2o provided at the tip of the bracket 19 is fitted onto the ball screw 14. Therefore, the rotation of the ball screw 14 causes the pole nut 20 to move along the axial direction of the ball screw 14, and therefore the movable base 12 is moved along the guide rail 13.

A circular support device @21 for holding the ball screw 14 is installed at the center of the first and second support devices 15, 16@.

As shown in FIG. 5, the intermediate support device 21 is slidably fitted into a base 22 installed in a direction perpendicular to the ball screw 14 and a guide groove 22a (FIG. 4) of this base 22. , first and second movable clamping bodies 23.24 for clamping the ball screw 14 from both sides, and air for moving the first and second movable clamping bodies 23.24 in the direction toward and away from the ball screw 14. or an oil-driven first;
and a second cylinder 25,26.

The first moving clamp 23 has rotating O-rollers 23a, 23b, the second moving clamp 24 has rotating rollers 24a, and the first and second cylinders, 25, 26,
When the second movable clamps 23 and 24 are simultaneously moved toward the ball screw 14, the rotating rollers 23a and 23b attached to the first movable clamp 23 and the second movable clamp 24
The outer peripheral surface of the ball screw 14 is rotatably held at three locations by a rotating roller 24a attached to the rotary roller 24a. Also, the first and second cylinders 25 and 26
When the second movable clamps 23, 24 are moved away from each other to the maximum extent, the pole nut 20 provided at the tip of the bracket 19 can pass between the two movable clamps 23, 24. The first and second cylinders 25, 26 are provided with limit switches 25a, 26a for detecting when both movable clamps 23, 24 have been retracted to their maximum limits.

On the side of the movable base 12, as shown in Fig. 3.4, a first
, second contact pieces 27 and 28 are provided protruding from the lower two stages of -F. A first limit switch 29 that is activated by contact with the first contact piece 27 and a second limit switch 30 that is activated by contact with the second contact piece 28 are installed on the top surface of the table base 11. There is.

The first limit switch 29 is disposed outside the second limit switch 30 with respect to the intermediate support device 21 and
There is.

First contact P! The positions of the ends 27a and 27b of 127 are as follows:
The ball nut 20 is the movable clamp holder 2 of the intermediate support device 121.
The first contact piece 27 is set to come into contact with the first limit switch 29 when located within a predetermined distance A from 3.24. An end 28a of the second contact piece 28,
28b, the pole nut 20 is located at the movable clamp holder 23.
The second contact piece 28 is set to come into contact with the second limit switch 30 when the second limit switch 30 is located within a predetermined distance B from the second limit switch 24. This first limit switch 29 is moved by the cylinder 25.26 when the first contact piece 27 comes into contact with the movable clamp 2. -3.24 separate from each other to release the grip on the ball screw 14, and when the contact is released, the movable gripping body 2
3.24 approaches each other and outputs a control signal so as to sandwich the ball screw 14.

When the pole nut 20 approaches the movable clamp 23.24 by a distance B and the second contact piece 28 contacts the second limit switch 3o, the retreat of the movable clamp 23.24 is caused by the limit switch 25a. , 26a, the driving of the motor 18 is stopped and the movement of the pole nut 2o is stopped.

In the ball screw bearing device with the above configuration, the pole nut 20
is not located within the distance A from the movable clamps 23, 24, the first limit switch 29 does not move, and therefore the ball screw 14, in addition to the first and second support devices 15, 16, It is rotatably supported by rotating rollers 23a, 123b and 24a of a U moving clamp holder 23.24 in the middle part of A. When the ball screw 14 is rotationally driven by the motor 18, the ball screw 14 is moved to the moving base 12. is guided along the guide rail 13 (movement 4
Ru.

For example, when the right end of the pole nut 2o reaches a predetermined distance Ak by moving from the state shown in FIG. 3 to the right (in FIG. 3),
A first contact 1127 contacts the first limit switch 29 . Therefore, the first and second cylinders 25.26 are operated, and the ball screw 14 is released from being held by the first and second movable clamps 23.24. When it moves further to the right and reaches a predetermined distance B, the second contact piece 28 contacts the second limit switch 30, and the limit switches 25a and 26a at this point actually move the movable clamping body 23.
．． It is confirmed whether 24 has retreated to the maximum limit, and if confirmation is obtained, it moves to the right. If confirmation is not obtained, the heptad 18 is stopped and the pole nut 20 is also stopped.

When the pole nut 20 moves further to the right and the left end of the pole nut 20 is separated from the predetermined distance A, the contact of the first contact piece 27 is released and the ball screw 14 is again clamped by the movable clamping bodies 23,24. When the pole nut 20 passes from the right to the left, the clamping is released in a similar manner so as not to obstruct the passage of the pole nut 20. Therefore, the ball screw 14 has the pole nut 20 in the predetermined path 111.
Unless the distance is close to 1A or more, the ball screw 14 is always supported by the intermediate support device 21 at an intermediate portion between the first and second support devices 15 and 16, and the apparent length of the ball screw 14 (
Since n> becomes 1/2, the critical rotational speed which is proportional to D/u increases significantly with respect to the diameter, and the inconvenience caused by high-speed rotation is eliminated.

In addition, in the embodiment described above, the case where the intermediate support device is installed at one location is exemplified, but it is also possible to install a plurality of intermediate support devices and support the ball screw 14 at two or more locations.

Further, instead of using the limit switch and the contact switch in the embodiment described in -1- to detect the moving position of the ball put 20, it is also possible to use photoelectric means or other appropriate means, or alternatively, the number of rotations of the ball screw 14 is counted and the The movement position of the pole nut 20 may be detected by calculating the count value.

As explained above, in the present invention, in addition to the first and second support devices that support the vicinity of both ends of the ball screw, at least one or more [points] within the movement range of the pole nut,
Since the ball screw is rotatably held by the intermediate support device which can be opened freely so as not to impede the movement of the pole nut, the critical rotational speed of the ball screw is greatly increased. Therefore, even in the case of a long and small diameter ball screw, high speed rotation is possible, vibration and noise are reduced, and movement accuracy is significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an outline of a conventional ball screw support device, Fig. 2 is an explanatory view showing the vibration of the ball screw, Figs. , FIG. 4 is a front view, and FIG. 5 is an enlarged side view of the intermediate support device. 11... Table base, 12... Moving base, 13... Guide rail, 14...
-Ball screw, 15...First support device, 16
...Second support device, 18...Motor, 19...Bracket, 20...Ball nut, 21...Intermediate support device, 22...
...Base, 23...First movable holding body, 24
...Second movable clamp body, 25...First
cylinder, 26... second cylinder, 27.
...First contact piece, 28...Second contact H129...First limit switch, 30.
...Second limit switch.

Claims (1)

[Claims] a ball screw into which a ball nut is fitted; first and second support devices that rotatably support the vicinity of both ends of the ball screw; a drive that rotationally drives the ball screw; and a drive that rotationally drives the ball screw; a guide rail that guides a moving base on which the pole nut is attached so that the pole nut moves along the axial direction of the ball screw; a releasable intermediate support device that rotatably clamps the ball screw at at least one location; when the pole nut approaches within a predetermined distance of the intermediate support device, the intermediate support device releases the ball screw; A ball screw bearing device equipped with an opening/closing control device that allows passage of a pole nut.