JPH025941B2 - - Google Patents

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, a ball nut fixed to the moving table side is fitted onto a ball screw as a means of moving a moving table that fixes a workpiece, and as the ball screw rotates, the ball nut moves in the axial direction of the ball screw. Many moving mechanisms are used in which the moving table is moved by the moving table.

As shown in FIG. 1, this ball screw 1 is rotatably supported by support devices 3 and 4 near both ends of the ball nut 2 so as not to interfere with the movement of the ball nut 2. In order to achieve this, 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, the diameter D of the ball screw 1 must be decreased to reduce the moment of inertia of the ball screw 1. 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 rotation critical speed (proportional to D/l) of the ball screw 1 becomes significantly small. For this reason, when the ball screw 1 is rotated at high speed,
As shown in (B) and (C), primary, secondary, and tertiary vibrations occur, resulting in severe noise and significant deterioration in movement accuracy.If the rotational speed is further increased, the ball screw and ball nut support parts are worn out. This caused many problems, including destruction.

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 and small ball screw is rotated at high speed.

For this purpose, in the present invention, the intermediate part of the ball screw is made to be in a state where it cannot be displaced in the radial direction.
By providing an intermediate support device which is releasably held by two rotatable rotating bodies, and by supporting the intermediate portion of the ball screw with this intermediate support device except when the ball nut is passing, the apparent length of the ball screw can be reduced. It is characterized by reducing the rotational speed and increasing the critical rotational speed, thereby eliminating the aforementioned vibrations, noise, reduction in movement accuracy, wear and tear, etc.

An embodiment of the present invention will be described below based on the drawings.

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

In the figure, reference numeral 11 denotes a table base, and reference numeral 12 denotes a movable base fixed to a movable table. The movable base 12 is slidably attached to a guide rail 13 fixed to the upper surface of the table base 11.

Further, a ball screw 14 is provided on the table base 11 in parallel to the guide rail 13. The ball screw 14 is rotatably supported by first and second support devices 15 and 16 near both ends thereof, and is rotated in either forward or reverse directions by a motor 18 via a gear mechanism 17 or the like.

A bracket 19 that projects in the direction of the ball screw 14 is fixed to the movable base 12.
A ball nut 20 provided at the tip of the ball screw 9 is fitted onto the ball screw 14. Therefore, the rotation of the ball screw 14 causes the ball 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.

An intermediate support device 21 for holding the ball screw 14 is installed approximately in the center between the first and second support devices 15 and 16.

As shown in FIG. 5, the intermediate support device 21 includes a base 2 installed in a direction perpendicular to the ball screw 14.
2 and the guide groove 22a of this base 22 (Fig. 4)
first and second movable clamping bodies 23, which are slidably fitted in and clamp the ball screw 14 from both sides;
24, and first and second cylinders 25 and 26 driven by air or oil that move the first and second movable clamping bodies 23 and 24 in the direction toward and away from the ball screw 14.

The first movable clamping body 23 has rotating rollers 23a, 2
3b, the second movable holding body 24 has a rotating roller 24a, and the first and second cylinders, 2
5 and 26, the first and second movable holding bodies 23,
24 to the ball screw 14 side at the same time,
Rotating rollers 23a and 23b attached to the first movable clamping body 23 and rotating roller 24a mounted to the second movable clamping body 24 allow the ball screw 10 to rotate in any radial direction on the outer circumferential surface of the ball screw 14. It is rotatably held in three places so that it cannot be displaced. Also, the first and second cylinders 2
5 and 26, the first and second movable holding bodies 23,
When the brackets 24 are moved away from each other to the maximum extent, the ball nut 20 provided at the tip of the bracket 19 can pass between the movable clamps 23 and 24. Limit switches 25a and 2 are installed in the first and second cylinders 25 and 26 to detect when both movable clamping bodies 23 and 24 have moved to the maximum limit.
6a is provided.

As shown in FIGS. 3 and 4, first and second contact pieces 27 and 28 are protruded from the side surface of the movable base 12 in two upper and lower stages. On the top surface of the table base 11,
A first limit switch 29 which is actuated by the contact of the first contact piece 27 and a second limit switch 30 which is actuated by the contact of the second contact piece 28 are provided.

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

The positions of the ends 27a and 27b of the first contact piece 27 are such that when the ball nut 20 is located within a predetermined distance A from the movable clamping bodies 23 and 24 of the intermediate support device 21, the ends 27a and 27b are in contact with the first limit switch 29. The pieces 27 are set to be in contact. The positions of the ends 28a and 28b of the second contact piece 28 are such that the second contact piece 28 contacts the second limit switch 30 when the ball nut 20 is located within a predetermined distance B from the movable clamping bodies 23 and 24. It is set as follows. This first limit switch 29
When the first contact piece 27 makes contact, the cylinder 2
5 and 26, the movable clamping bodies 23 and 24 move away from each other to release the clamping of the ball screw 14, and when the contact is released, the movable clamping bodies 23 and 24 approach each other and clamp the ball screw 14 using a control signal. Output.

When the ball nut 20 approaches the movable clamps 23, 24 to a distance B and the second contact piece 28 contacts the second limit switch 30, the retreat of the movable clamps 23, 24 causes the limit switches 25a,
26a, motor 1
8 is stopped, and movement of the ball nut 20 is stopped.

In the ball screw support device having the above configuration, when the ball nut 20 is not located within the distance A from the movable clamping bodies 23 and 24, the first limit switch 2
9 is not activated, so the ball screw 14 is in the first position,
In addition to the second support devices 15, 16, rotating rollers 23 of the movable clamps 23, 24 in their intermediate parts
It is rotatably supported by a, 23b, and 24a. When the ball screw 14 is rotationally driven by the motor 18, the ball screw 14 moves together with the movable base 12 while being guided by the guide rail 13.

When the ball nut 20 moves to the right (in FIG. 3) from the state shown in FIG. 3 and the right end of the ball nut 20 reaches a predetermined distance A, the first contact piece 27 comes into contact with the first limit switch 29. Therefore, the first and second cylinders 25 and 26 operate, and the first and second cylinders 25 and 26 operate.
The ball screw 14 is released from being held by the movable holding bodies 23 and 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, 26a at this point actually move the movable clamps 23, 24 to the maximum. It is confirmed whether the retreat has reached the limit, and if confirmation is obtained, it moves to the right. If confirmation is not obtained, the motor 18 is stopped and the ball nut 20 is also stopped. The ball nut 20 moves further to the right,
When the left end of the ball nut 20 moves away 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 and 24. When the ball nut 20 passes from the right to the left, the grip is released in a similar manner so as not to prevent the ball nut 20 from passing. Therefore, the ball screw 14 is connected to the ball nut 20 at a predetermined distance A.
Otherwise, 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 (l) of the ball screw 14 is reduced to 1/2. Therefore, the dangerous critical speed of rotation, which is proportional to D/l with respect to the diameter D, increases significantly, and the inconvenience caused by high-speed rotation is eliminated.

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

Furthermore, instead of using the limit switch and contact piece in the above embodiment to detect the moving position of the ball nut 20, it is also possible to use photoelectric means or other appropriate means, or alternatively, the number of revolutions of the ball screw 14 is counted and this counted value is calculated. The moving position of the ball nut 20 may also be detected.

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 support device within the movement range of the ball nut is provided.
In the above location, the ball screw is rotatably held by at least three rotating bodies in a state in which it cannot be displaced in the radial direction by an intermediate support device that can be opened freely so as not to hinder the movement of the ball nut. Therefore, when the long and small diameter ball screw 14 is rotated at high speed, the ball screw 14 is deflected in the radial direction due to the primary, secondary, and tertiary vibrations shown in Fig. 2 A, B, and C. Even if the ball screw 14 is held in the middle by at least three rotating bodies so as not to be able to deflect, such vibrations can be significantly reduced, and noise can also be significantly reduced, reducing wear and tear. Not only can this be reduced, but also the movement accuracy of the ball nut 20 can be significantly improved.
Since the intermediate portion of the ball screw 14 is supported in this manner, the critical rotational speed of the ball screw described above is significantly increased.
0 movement speed can be realized.

[Brief explanation of drawings]

Fig. 1 is a plan view schematically showing a conventional ball screw support device, Fig. 2 is an explanatory view showing vibration of the ball screw, Figs. 3 to 5 show an embodiment of the present invention, and Fig. 3 is a plan view thereof. , FIG. 4 is a front view, and FIG. 5 is an enlarged side view of the intermediate support device. 11...Table base, 12...Moveable base, 1
3...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 clamping body, 25... first cylinder, 26...
...Second cylinder, 27...First contact piece, 28...
...Second contact piece, 29...First limit switch, 30...Second limit switch.

Claims (1)

[Claims] 1. A ball screw 1 into which a ball nut 20 is fitted.
4, the first and second support devices 15 and 16 that rotatably support the vicinity of both ends of the ball screw 14, a drive device that rotationally drives the ball screw 14, and a drive device that rotationally drives the ball screw 14. the ball nut 20 along the axial direction of the ball screw 14
a guide rail 1 that guides the movable base 12 to which the ball nut 20 is attached so that the ball nut 20 moves;
3, and clamping the outer periphery of the ball screw 14 in a state in which the ball screw 14 cannot be displaced in the radial direction at at least one or more locations within the movement range of the ball nut 20 between the first and second support devices 15 and 16; In addition, in the clamped state, the ball screw 1
A movable clamping device having a plurality of at least three rotating bodies that rotate with the rotation of the ball screw 14, and moving at least one rotating body so that the rotating bodies are held close to the ball screw 14 or separated and released. an intermediate support device 21 having a body; the ball nut 20 is connected to the intermediate support device 21;
an opening/closing control device that releases the grip of the ball screw of the intermediate support device 21 when the intermediate support device 21 approaches within a predetermined distance of the ball nut 20, and allows the ball nut 20 to pass through.