JPS6231235Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a ball screw type feed device for a machine tool, and more particularly to a support device for a ball screw.

BACKGROUND ART Conventionally, in machining centers, drilling machines, etc., ball screw type feed devices have been frequently used to move the table back and forth, left and right, or move the spindle head up and down in order to improve drive efficiency and achieve high precision feed. Of the above, the ball screws for horizontal movement of the table and the vertical movement of the spindle head can be supported by bearings at both ends, but for the ball screws for movement of the table back and forth, the rear end is supported by bearings. It was difficult to do so.

In other words, machining centers and drilling machines often have an open structure in which the space between the rear of the table and the column is used as a space for discharging chips, while the rear end of a ball screw for moving the table back and forth is used as a space for discharging chips. Because it is located in a space, it is necessary to cover that part with something to prevent dust. However, a fixed cover to which a bearing can be attached restricts the table stroke, and therefore the table must be covered with a cover that moves with the table.As a result, it becomes difficult to support the table with the bearing, and the table stroke is restricted. The reality is that the ends have no choice but to be free ends. However, when one end of the ball screw is set as a free end, that is, a cantilever support method lacks stability, and has drawbacks such as being prone to runout, restricting high-speed rotation, and producing abnormal noise.

In view of the above-mentioned problems, the purpose of this invention is to
To provide a ball screw support device for a machine tool capable of stably supporting a ball screw with both ends when the ball screw is used in a situation where at least one end of the ball screw must be covered with a movable cover. It is in.

In order to achieve the above object, the present invention supports one end of a ball screw rotatably on the fixed side under axial restraint, and also includes a centering cylinder protruding from the ball nut in the shape of a cover along the axial direction. The ball screw is supported in a stable and centered state by rotatably pivoting a supporting member slidably fitted on the inner periphery of the ball screw to the other end of the ball screw. .

Embodiments of the present invention will be specifically described below with reference to the drawings. This example was carried out targeting a machining center, and 1 in the figure is the bed.
A saddle 2 is placed on the bed 1 so as to be movable back and forth via a pair of left and right slide guides 3, and a table 4 is placed on the saddle 2 so as to be movable left and right via a pair of front and rear slide guides 5. has been done. Reference numeral 6 denotes a column, on the top of which a spindle head 7 and an automatic tool changer 8 are installed. The above-described movement of the saddle back and forth, movement of the table left and right, and lifting and lowering of the main shaft are each carried out by a ball screw type feeding device.

Next, in the above-mentioned machining center, a ball screw type feeding device for moving the table 4 back and forth, that is, the saddle 2 back and forth, which is the main part of the present invention, will be explained. Reference numeral 9 denotes a ball screw, which is arranged in parallel to the left and right slide guides 3 at an approximately intermediate position on the upper side of the bed 1. The front end of the ball screw 9 is rotatably supported by the bed 1 via a bearing 10 in an axially restrained state, and is rotationally driven by a feed motor 11 installed in the bed 1 via a gear train 12. It's becoming like that.

Reference numeral 13 denotes a ball nut that is fixed to the lower surface of the saddle 2 at approximately the center thereof and is screwed onto the ball screw 9.
The rear end of is supported. That is, one end of a retaining ring 16 for mounting is fitted onto the flange portion 15 on the rear side of the ball nut 13, and is fastened with an appropriate number of bolts 17.
The open end of the centering cylinder 14 is fitted into the other end of the centering cylinder 6 and is fastened with an appropriate number of bolts 18. A ring-shaped support member 19 is fitted inside the centering cylinder 14, which covers the rear part of the ball screw 9 and whose rear end is closed by a cover plate 14a, so as to be slidable in the axial direction. , the support member 19 rotatably supports the rear end of the ball screw 9 via a bearing 20. Thus, the ball screw 9 is rotatably supported at its front end by the bed 1 and by its rear end by the saddle 2 via bearings 10 and 20, respectively, thereby supporting the ball screw 9 on both sides. In addition, 21 is an annular liner interposed between the support member 19 and the centering cylinder 14 in order to improve the slidability of the support member 19, 22 is a bearing holder, and 23 is a saddle on the inside of the bearing support part of the ball screw 9. This is a stopper provided for safety purposes to prevent the accidental runaway of 2.

The front upper surface of the bed 1, including the front side of the ball screw 9, is covered by a retractable cover 24 attached to the bed 1 and the saddle 2, while the rear upper surface of the bed 1 is open for discharging chips. It also has a chip receiver 25. Note that 26 is a hole formed in the lower part of the column 6 to allow movement of the centering cylinder 14 when the saddle 2 moves backward.

This embodiment is configured as described above,
Therefore, when the ball screw 9 is rotated forward or backward by the electric motor 11 via the gear train 12, the table 4 together with the saddle 2 is moved forward or backward via the ball nut 13, and accordingly the centering tube 14 integrated with the ball nut 13 is slid while holding it against the support member 19 of the ball screw 9. In other words, since the support member 19 rotatably supports the ball screw 9 while being supported by the centering tube 14 assembled concentrically to the ball nut 13 as described above, the ball screw 9 can rotate in a stable state, enabling high-speed feeding with high precision.

As described above in detail, in the case where the ball screw is used under the circumstances where at least one end of the ball screw must be covered by a movable cover, the present invention has eliminated the conventional defects and stably supported the ball screw by rotatably supporting one end of the ball screw by a support member slidably fitted on the inner circumference of a centering cylinder that protrudes from the ball nut in the axial direction like a cover.
In this device, by providing a centering tube on the ball nut, it is not only easy to center the ball screw itself, but the centering tube is also effective not only for supporting the ball screw but also as a dust cover against cutting chips, etc., and it greatly simplifies the support and dustproof structure for the ball screw.

Although the present invention has been described with reference to a feeding device for moving a table back and forth in a machining center, it is not limited thereto.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an overall front view, FIG. 2 is a side view, FIG. 3 is a side sectional view showing the ball screw type feed device, and FIG. 4 is a side sectional view showing the main parts. It is a diagram. 1...Bed, 2...Saddle, 4...Table, 9...Ball screw, 13...Ball nut,
14... Center-holding tube, 19... Supporting member, 10, 20
……bearing.

Claims (1)

[Scope of utility model registration request] In a ball screw type feed device for a machine tool that moves a movable table via a ball nut screwed onto a ball screw rotationally driven by a feed drive device, one end of the ball screw is axially restrained on a fixed side. At the same time, a support member slidably fitted to the inner periphery of a centering cylinder protruding from the ball nut in the axial direction in the form of a cover is rotatably supported at the other end of the ball screw. A ball screw support device for a machine tool, characterized by: