JPH08276340A - Feed screw supporting device of machine tool - Google Patents

Abstract

PURPOSE: To obtain a supporting device with an excellent durability as with as with a stable operation, by providing a pressing body which collides with the cam surfaces of the advancing end and the retreating end of the screw connection of a moving body with a feed screw, and rotates a rotary top in the regular direction or the reverse direction. CONSTITUTION: Since the middle part in the longitudinal direction of a feed screw 18 is supported by a supporting device 30, a bending, a distortion, and the like of the feed screw 18 are prevented. When the gear box 23 of a shear approaches the supporting device 30, that is a rotary top 31, by the movement of rollers 35a and 35b provided on the gear box 23 collide with one side of cam surfaces 34a and 34b provided to the rotary top 31, so as to rotate the rotary top 31 in one direction, one side of the rotary top 31 is separated from the feed screw 18, and it is retreated to the side from the gear box 23. At the same time, the other side of the rotary top 31 approaches the feed screw 18 so as to support the feed screw 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine tool for supporting a middle portion of a feed screw used for controlling the movement of a head or a table in the left-right (horizontal) direction and preventing the bending or the runout of the feed screw. The present invention relates to a feed screw supporting device.

[0002]

2. Description of the Related Art Conventionally, it has been as shown in FIG.
In FIG. 4, reference numeral 1 is a bed (frame) extending in the left-right direction, and a table 2 is placed on the bed 1 via rails (not shown) so as to be slidable in the left-right direction. Further, the elongated feed screw 3 is extended in the left-right direction, the left and right ends thereof are supported by the left and right ends of the bed 1, and the table 2 is screw-connected to the feed screw 3. That is, table 2
The bracket 2a is formed so as to project downward and is screwed to the feed screw 3 through the bracket 2a. The bed 1 is provided with a support device 5 for supporting the intermediate portion of the feed screw 3 in the left-right direction.

In this support device 5, a cylinder 6 which expands and contracts in the vertical direction is erected and fixed to the bed 1 via legs 7, and an arcuate bearing 8 is fixed to the upper end of the cylinder 6. The bearing 8 rises when the cylinder 6 extends and contacts the lower surface of the feed screw 3 at the intermediate portion in the left-right direction, and when the cylinder 6 shortens, the bearing 8 is lowered to a position lower than the bracket 2a of the table 2.
Further, a limit switch 9 for expanding and contracting the cylinder 6 is provided on the side portion of the leg 7 positioned on the side of the feed screw 3 and the cylinder 6, while the limit switch 9 is turned on / off on the side portion of the bracket 2a. The pressing body 10 is provided. Accordingly, when the table 2, that is, the bracket 2a approaches the bearing 8, the cylinder 6 is shortened and the bearing 8 is moved.
To allow the bracket 2a to pass therethrough, and after the bracket 2a has passed the bearing 8, the cylinder 6 is extended to raise the bearing 8 and support the lower surface of the intermediate portion of the feed screw 3. To do.

[0004]

In the above-mentioned conventional one, when the cylinder 6 is not shortened due to the contact failure of the limit switch 9 or the response of the cylinder 6 becomes slow, the bracket 2a collides with the bearing 8. The bearing 8 and the cylinder 6 are damaged and the feed screw 3 is damaged. SUMMARY OF THE INVENTION It is an object of the present invention to obtain a novel feed screw support device for a machine tool that solves the above drawbacks.

[0005]

The present invention is configured as follows to achieve the above object. That is, the elongated feed screw is arranged in parallel with the frame extending in the left-right direction, and the left and right ends thereof are supported by the left and right ends of the frame,
A movable body supported by a frame so as to be movable in the left-right direction is screw-connected to the feed screw, a short rotation piece is arranged on a side portion of a longitudinal intermediate portion of the feed screw, and the center portion in the left-right direction is vertically arranged. A pair of support pieces that are rotatably connected to the frame by fulcrum pins, project in the feed screw direction at the left and right ends of the rotating piece, and alternately face the lower surface of the feed screw when the rotating piece rotates in the forward and reverse directions. And a pair of cam surfaces that smoothly incline toward the feed screw direction are provided on the left and right facing surfaces of the support piece, and the cams are provided at the advancing end and the backward advancing end of the screw connecting portion with the feed screw of the moving body. In this structure, a pressing body that collides with the surface and rotates the rotating piece in the forward and reverse directions is provided. In this case, it is preferable to provide a holder that holds the rotating piece with a predetermined force when the amount of rotation of the rotating piece in the forward and reverse directions reaches a predetermined value. Also, the holder may be a magnet.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is a partial cross-sectional plan view showing an essential part thereof, and FIG. 3 is a side cross-sectional view thereof. In FIG. 1, 15 is the Y axis (left and right)
Is a cross column (frame) of a machine tool that extends in the direction, and a slide (moving body) 17 to which a head (not shown) is attached is slidably mounted on a front surface (right surface) side via a rail 16 extending in the Y-axis direction. Stop. Cross column 15 above
2, an elongated feed screw (Y-axis feed screw) 18 is arranged in the left-right direction extending the cross column 15, and both ends thereof are provided at both left and right end portions of the cross column 15. Lock on body 19.

The above-mentioned sile 17 is screwed to the feed screw 18. That is, the bracket 2 is provided at the rear of the silet 17.
A gear box 23 is attached via the shaft 2, and a nut 24 and a driven gear 25 that are coaxially and integrally connected to each other are rotatably supported in the gear box 23. Then, the nut 24 is screwed into the feed screw 18, and as shown in FIG. 1, the driven gear 25 meshes with the drive gear 26 of the Y-axis servo motor 27 attached to the bracket 22, and the Y-axis servo motor 27. Is rotated in the forward and reverse directions to control the movement of the sile 17 in the Y-axis (left-right) direction, that is, in the left-right direction in FIG.

At the center of the cross column 15 in the left-right direction, a support device 30 for supporting an intermediate portion of the feed screw 18 in the longitudinal direction (left-right direction) is provided. The supporting device 30 is as follows. That is, a short rotation piece 31 is arranged behind the longitudinal middle portion of the feed screw 18, and the center portion in the left-right direction is vertically fixed to the cross column 15 via a mounting plate 36 to a vertical fulcrum pin 32. Connect rotatably.
The rotating piece 31 integrally has a pair of supporting pieces 31a, 31b projecting forward, that is, in the direction of the feed screw 18, at both left and right ends of the rotating piece 31.
By the rotation of 1 in the forward / reverse direction (the arrow A / B direction in FIG. 2), the lower surface of the feed screw 18 is alternately faced. On the upper surface of each of the support pieces 31a and 31b, resin-made contact pieces 33a and 33b having high lubricity are placed and integrally fixed by screws or the like.

A pair of cam surfaces 34a, 34b are formed on the left and right facing surfaces of the support pieces 31a, 31b. Each cam surface 34a, 34b spreads smoothly toward the feed screw 18. On the other hand, rollers (pressing bodies) 35a and 35b that collide with the cam surfaces 34a and 34b are attached to the left and right of the rear end of the gear box 23 described above. This roller 35a,
When the gear box 23 passes through the rotating piece 31 portion from the left side to the right side in FIG. 2, the roller 35b of the right portion collides with the cam surface 34b of the right portion 35b. 2 is rotated in the direction of arrow (a), and conversely, when the gear box 23 passes through the rotating piece 31 part from the right side to the left side in FIG. It collides with the surface 34a and rotates the rotating piece 31 in the arrow (A) direction.

When the rotating piece 31 is rotated in the direction of arrow (a), the right contact piece 33b is separated from the feed screw 18, and the left contact piece 33a is located below the feed screw 18. And the left contact piece 33a supports the feed screw 18. Further, when the rotating piece 31 is rotated in the arrow (A) direction, the left contact piece 33a is separated from the feed screw 18, and the right contact piece 33b is released.
The contact piece 33b on the right side of the lead screw 18
Support.

As shown in FIGS. 2 and 3, the rotating piece 31 is provided with a pair of arc-shaped guide holes 37 and a ball plunger 40 on the left and right sides sandwiching the fulcrum pin 32. A pin 38 fixed upright to the mounting plate 36 on the cross column 15 side is slidably inserted, and a washer-shaped ring 39 is locked to the upper end of the pin 38 to prevent the rotating piece 31 from rising. Also, the ball plunger 40
Is elastically biased downwardly to the ball 40a,
When the amount of rotation in the normal / reverse (arrow a / a) directions of 2 reaches a predetermined value, it engages with the left and right two sets (4) of positioning recesses 40 provided on the side of the mounting plate 36, and the rotation is performed. The piece 31 is held with a predetermined force so as not to rotate carelessly.

Further, as shown in FIG. 2, a pair of stopper devices 44 are provided on the left and right behind the rotary piece 31. In this stopper device 44, a stopper pin 46 is loosely fitted to a bracket 45 fixed to the cross column 15 toward the rear surface of the rotating piece 31, and a coil spring 47 urges the stopper pin 46 toward the rotating piece 31. A magnet (permanent magnet) 48 is attached to the tip of each stopper pin 46. On the other hand, a pair of iron collision pins 5 are provided on the rear surface of the rotating piece 31.
0 is fixed in correspondence with the magnet 48. Here, the ball plunger 40, the positioning recess 41 into which the ball plunger 40 is fitted and locked, and the magnet 48 and the collision pin 50 to which the magnet attracts form a holder for the rotating piece 31 in the present invention. The feed screw according to the present invention may be a table-driving feed screw that is attached to the bed side and screw-connects the table.

According to the above-described embodiment, the feed screw 18 is supported by the support device 30 at the intermediate portion in the longitudinal direction, so that the bending and swinging of the feed screw 18 can be prevented. And
When the gear box 23 approaches the supporting device 30, that is, the rotating piece 31, by the movement of the shiray 17, one of the rollers 35a and 35b provided on the gear box 23 collides with one of the cam surfaces 34a and 34b, and the above-mentioned rotation. The moving piece 31 rotates in one direction, and one of the rotating pieces 31 is separated from the feed screw 18 and retracts laterally from the gear box 23.
The other of the rotating pieces 31 comes close to and supports the feed screw 18.

When the rotary piece 31 is rotated a predetermined amount toward one side or the other side, the collision pin 50 provided on the rotary piece 31 collides with the stopper pin 46 to prevent further rotation. It Then, the collision pin 50 is attracted to the magnet 48, and each ball plunger 40
Engages with and locks in the positioning recess 41 of one set or the other set, and holds the rotating piece 31 with a predetermined force to prevent inadvertent rotation. In FIG. 3, reference numeral 51 denotes a pressure ring fitted to the upper part of the fulcrum pin 32 and brought into contact with the upper surface of the rotary piece 31, and 52 presses the rotary piece 31 downward via the pressure ring 51. Brake spring.

[0015]

As is apparent from the above description, according to the present invention, when the screw connecting portion of the moving body with the feed screw passes through the rotating piece portion, the pressing body provided on the screw connecting portion is rotated. Since the rotating piece is made to rotate in the forward and reverse directions by colliding with the cam surface of the piece, and the intermediate portions of the feed screw are alternately supported by the supporting pieces provided at both ends of the rotating piece, the operation is stable. In addition, it is possible to obtain a highly durable support device without failure.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a partial cross-sectional plan view of a supporting device portion according to the present invention.

FIG. 3 is a side sectional view of a supporting device portion according to the present invention.

FIG. 4 is a sectional view of a supporting device portion showing a conventional example.

[Explanation of symbols]

 15 Cross Column 16 Rail 17 Shire (Moving Body) 18 Feed Screw 19 Support 22 Bracket 23 Gear Box 24 Nut 25 Driven Gear 26 Drive Gear 27 Y-axis Servo Motor 30 Support Device 31 Rotating Piece 31a, 31b Support Piece 32 Support Point Pin 33a, 33b Contact piece 34a, 34b Cam surface 35a, 35b Roller 36 Mounting plate 37 Guide hole 38 Pin 39 Ring 40 Ball plunger 40a Ball 41 Positioning recess 44 Stopper device 45 Bracket 46 Stopper pin 47 Coil spring 48 Magnet 50 Collision pin 51 Addition Pressure ring 52 Brake spring

Claims (3)

[Claims] 1. A feed member comprising a slender feed screw arranged in parallel with a frame extending in the left-right direction, the left and right ends of which are supported by the left and right ends of the frame, and the frame being movably supported by the frame. A short rotation piece is arranged on the side of the longitudinal intermediate portion of the feed screw, and the center portion in the left-right direction is rotatably connected to the frame by a vertical fulcrum pin. Providing a pair of support pieces on both left and right sides, which project in the direction of the feed screw and alternately face the lower surface of the feed screw by the rotation of the rotating piece in the forward and reverse directions. A pair of cam surfaces that smoothly incline toward each other are provided, and the rotating piece is rotated in the forward and reverse directions by colliding with the cam surface at the advancing end and the backward moving end of the screw connecting portion with the feed screw of the moving body. It is characterized by the provision of a pressing body for Machine tool feed screw support device. 2. A holding tool for holding the turning piece with a predetermined force when the turning amount of the turning piece in the forward and reverse directions reaches a predetermined value. Machine feed screw support device. 3. The feed screw supporting device for a machine tool according to claim 2, wherein the holder is a magnet.