JPH0754678Y2 - Screw feed mechanism - Google Patents

Description

The present invention relates to a screw feed mechanism, and more particularly to a screw feed mechanism applied to a feed device for a moving table such as a slicing machine or a machine tool.

[Conventional technology]

Conventionally, this type of screw feed mechanism has been used as shown in FIG.
Supports 12, 14 are erected on the base 10, and the supports 12,
A screw rod 20 is rotatably supported by 14 via bearings 16 and 18. The right end 20A of the screw rod 20 is connected to the motor 2 via the clutch 22.
Directly connected to 4. The screw portion 20B of the screw rod 20 is screwed into the nut portion 26A of the moving table 26, and when the screw rod 20 rotates, the moving table 26 moves left and right in FIG.

[Problems to be solved by the device]

However, in the screw feed mechanism shown in FIG. 4, when the cores of the bearing 16 and the bearing 18 supporting the screw rod 20 are displaced, when the screw rod 20 rotates in this state, the screw rod 20 swings and the moving table 26 However, it has the drawback that it cannot move smoothly.

In order to solve such a problem, there is a method of improving the dimensional accuracy of each member to perform centering, but there is a problem that the number of assembly and part processing steps increases.

Another embodiment of the screw feeding mechanism is one in which a floating device is built in the support base 14 shown in FIG. 4, and when the cores of the bearing 16 and the bearing 18 are misaligned, the misalignment is corrected. However, if a floating device is provided,
There is a drawback in that the screw feed mechanism becomes complicated and large in size.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a screw feed mechanism capable of smoothly moving a moving table with a simple structure.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a nut member slidably supported with respect to a fixing member, a screw part formed on the outer periphery and rotatably supported by the fixing member. A portion that is screwed into the screw hole of the nut member and that rotates to move the nut member, and an outer cylinder that is disposed in the outer cylinder and that has one end fixed to the outer cylinder so that rotational force can be transmitted and the other end. And an inner shaft that is connected to a drive source and has an elastic portion formed at an intermediate portion thereof to elastically deform to absorb misalignment at both ends.

[Action]

According to the present invention, the outer cylinder (20) rotatably supported by the fixing member (12) is formed with the elastic portions (29, 32c) which absorb the misalignment of both ends by elastic deformation. The inner shaft (28) is arranged, one end of the inner shaft (28) is fixed to the outer cylinder (20), and the other end is connected to the drive source (24). Further, the outer cylinder (20) has a threaded portion (20a) formed on the outer periphery thereof, and the threaded portion (2
0a) is screwed to the moving member (26). As a result, when the core of the fixed member (12) and the drive source (24) are misaligned, the elastic parts (29, 32c) of the inner shaft (28) elastically deform and absorb the misalignment, so that the outer cylinder The (20) rotates smoothly and the moving member (26) screwed into the outer cylinder (20) can be moved smoothly.

〔Example〕

Hereinafter, preferred embodiments of a screw feeding mechanism according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of the screw feeding mechanism according to the present invention, and the same or similar members as those of the conventional example shown in FIG.

In FIG. 1, this screw feed mechanism has support bases 12 and 14 provided upright on a base 10, and an outer cylinder 20 is mounted on the support base 12 via a bearing 16.
The left end of the is rotatably supported. A screw portion 20a is formed on the outer circumference of the outer cylinder 20 and is screwed with a nut portion 26a of the moving table 26.

An inner shaft 28 is arranged inside the outer cylinder 20.
The left end of the inner shaft 28 is disposed coaxially with the central axis of the outer cylinder 20, and is attached to the left end of the outer cylinder 20 with a stop pin 30.
The right end 28b of the inner shaft 28 is connected to the drive motor 24 via the bearings 18 and 18 of the support 14 and the clutch 22. In addition, constricted portions 29, 29 are formed on the surface of the inner shaft 26 at predetermined intervals in the circumferential direction.

Next, the operation of the screw feed mechanism configured as described above will be described.

First, normal drive force transmission will be described. The inner shaft 28 is
When the drive motor 24 is driven, it rotates via the clutch 22 and the outer cylinder 20 can be rotated in the direction of the arrow. Therefore, the movable table 26 can be moved in the left-right direction in FIG. 1 (the axial direction of the outer cylinder 20) by the rotation of the outer cylinder 20.

Next, a case where the cores of the bearing 16 and the bearing 18 are displaced will be described.

For example, when the core of the bearing 18 is displaced to the upper side with respect to the core of the bearing 16, the inner shaft 28 is elastically deformed by a small amount of α ° at each of the constricted portions 29, 29 having a thin wall as shown in FIG. Then, the misalignment amount 1 of the core is absorbed. Further, the constricted portions 29, 29 can appropriately elastically deform a minute amount and absorb the deviation even when the core is displaced in all directions.

Therefore, since the deviation can be absorbed by the constricted portions 29 of the inner shaft 28, the outer cylinder 20 can be smoothly rotated and the moving table 26 can be smoothly moved even when the core is misaligned.

FIG. 3 shows a modification of the inner shaft. This inner shaft 32
Is used instead of the inner shaft 28, and its left end
The diameters of 32a and the right end portion 32b are formed to be large, and the middle portion is a thin stem portion.
It is formed as 32c.

Therefore, when the cores of the support base 12 and the support base 14 are misaligned, the inner shaft 32 has a small diameter small stem portion (constricted portion) 32c.
Can elastically deform by a small amount and absorb the deviation,
The same effect as that of the inner shaft 28 described above can be obtained.

In this embodiment, the inner shaft is provided with a constricted portion to absorb the misalignment, but the invention is not limited to this.
You may interpose a leaf spring in the middle of the inner shaft and use the leaf spring to absorb the misalignment.

Further, the difference between the feed amount when the core is not displaced and the feed amount that occurs when the inner shaft absorbs the core displacement is negligibly small, so that the feed amount is not adversely affected.

[Effect of device]

As described above, according to the screw feeding mechanism of the present invention, the elastic portion that absorbs the misalignment of both ends by elastically deforming in the intermediate portion is provided inside the outer cylinder rotatably supported by the fixing member. The formed inner shaft is arranged, one end of the inner shaft is fixed to the outer cylinder, and the other end is connected to the drive source. As a result, when the core of the fixed member and the drive source are misaligned, the elastic part of the inner shaft elastically deforms and absorbs the misalignment, so that the outer cylinder can be smoothly rotated and the movable member can be smoothly moved. You can Further, since the floating mechanism is unnecessary, the screw feed mechanism can be downsized.

[Brief description of drawings]

1 is a sectional view showing an embodiment of a screw feeding mechanism according to the present invention, FIG. 2 is a front view showing a first embodiment of an inner shaft applied to the screw feeding mechanism according to the present invention, and FIG. FIG. 4 is a front view showing a second embodiment of the inner shaft, and FIG. 4 is a sectional view showing an embodiment of a conventional screw feed mechanism. 10 ... Base, 12 ... Supporting base, 14 ... Driving support, 20 ... Outer cylinder, 28, 32 ... Inner shaft, 29, 29 ... Constricted part.

Claims (1)

[Scope of utility model registration request] 1. A nut member slidably supported with respect to a fixed member, and a threaded portion formed on the outer periphery and rotatably supported by the fixed member, the threaded portion being a screw of the nut member. An outer cylinder that is screwed into the hole and rotates to move the nut member, and is arranged in the outer cylinder. One end of the outer cylinder is fixed to the outer cylinder so that rotational force can be transmitted, and the other end is connected to a drive source. A screw feed mechanism comprising: an inner shaft having an elastic portion that absorbs misalignment at both ends by elastically deforming the intermediate portion.