JP2002340129A - Ball screw device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise of a ball screw device. SOLUTION: In this ball screw device provided with a screw shaft 3 having a spiral screw groove 2 on an outer peripheral surface, a ball nut 6 which has a screw groove corresponding to the screw groove 2 of the screw shaft 3 on an inner peripheral surface and is loosely fitted into the screw shaft 3 and many balls arranged to roll between both of the screw grooves and circulating by being guided by a ball circulating part 50A mounted with a ball on the ball nut 6, surrounding members 21 and 25 for surrounding the ball circulating part 50A are provided, and foamed resin 29 is filled among the surrounding members 21 and 25 and the ball nut 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ball screw device used for a feeder or the like.

[0002]

2. Description of the Related Art As a conventional ball screw device of this type, for example, the one shown in FIG. 3 is known. In this ball screw device 1, a ball nut 6 having a screw groove 4 having a semicircular cross section on the inner peripheral surface is fitted on a screw shaft 3 having a screw groove 2 having a semicircular cross section on the outer peripheral surface and extending in the axial direction. Have been combined. The ball nut 6 includes a cylindrical portion 6 a fitted to the screw shaft 3 and the cylindrical portion 6.
and a flange portion 6b provided at an end in the axial direction of FIG.

The screw groove 4 of the ball nut 6 and the screw groove 2 of the screw shaft 3 are opposed to each other to form a helical passage therebetween, and the helical passage has a large number of steels as rolling elements. A ball 5 is rollably mounted. The rotation of the screw shaft 3 causes the ball nut 6 to move linearly through the rolling of the ball 5. When the ball nut 8 moves linearly, the ball 5 is
Moves while rolling in the spiral passage formed by the above. However, in order to continuously move the ball nut 6, the ball 5 needs to be circulated infinitely.

[0004] For this reason, a circulation hole 51, which is connected to the thick portion of the cylindrical portion 6 a of the ball nut 6 from the tangential direction to the helical passage and straddles the screw shaft 3 and opens to the outside of the nut in a pair, A ball circulation path 52 is formed by forming the circulation holes 51 and 51 with a substantially U-shaped return tube (ball circulation part) 50A (in the figure, two ball circulation paths 52 are provided). is there). After moving the helical path by, for example, 1.5 turns, the ball 5 is guided to the ball circulation path 52 and repeats infinite circulation.

[0005]

However, in the above-mentioned conventional ball screw device, since noise is generated when the ball 5 circulates in the return tube 50A, the ball screw device is used in an environment where low noise and noise reduction are required. A problem arises when used. The present invention has been made in order to solve such inconvenience, and an object of the present invention is to provide a ball screw device capable of reducing noise.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 comprises a screw shaft having a helical screw groove on an outer peripheral surface, and a screw groove corresponding to the screw groove of the screw shaft. A ball nut loosely fitted to the screw shaft having an inner peripheral surface, and a number of balls rotatably arranged between the two screw grooves, the balls being attached to the ball nut. A ball screw device guided and circulated by a ball circulation component, wherein a surrounding member surrounding the ball circulation component is provided, and a sound absorbing material is filled between the surrounding member and the ball nut.

According to a second aspect of the present invention, in the first aspect, a damping metal plate is used as the surrounding member.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway explanatory view for explaining a ball screw device which is an example of an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. Note that the basic configuration of the ball screw device of this embodiment is the same as the conventional configuration described with reference to FIG. 3 except that the return tube is used as one path, and only the differences will be described. Are denoted by the same reference numerals and description thereof will be omitted.

Referring to FIG. 1 and FIG. 2, this ball screw device 20 has an outer cylindrical portion 21 which is inserted into the cylindrical portion 6a of the ball nut 6 at a predetermined interval. Outer cylinder 2
A flange portion 22 is provided at an end of the one ball nut 6 on the flange portion 6b side, and the flange portion 22 is fixed to the flange portion 6b by a fixing means such as a screw 23. On the other hand, the end of the outer cylinder 21 on the side away from the flange 6b of the ball nut 6 is the cylinder 6a of the ball nut 6.
An opening 24 protrudes slightly from the opening 2.
Reference numeral 4 is closed by a lid 25 externally inserted into the screw shaft 3. The surrounding member of the present invention is constituted by the lid portion 25 and the outer cylindrical portion 21 so as to surround the return tube 50A as a ball circulating component attached to the cylindrical portion 6a of the ball nut 6 by the surrounding member. Has become.

The lid portion 25 has a small diameter portion 26 having substantially the same diameter as the inner diameter of the outer cylinder portion 21 and a large diameter portion 27 having substantially the same diameter as the outer diameter of the outer cylinder portion 21.
The small-diameter portion 26 is moved from the opening 24 to the outer cylindrical portion 2.
1, the end surface of the small-diameter portion 26 abuts against the end surface of the cylindrical portion 6a of the ball nut 6, and in this state, the outer cylindrical portion 21
Is fixed to the small-diameter portion 26 by a fixing means such as a screw 28, so that the opening 24 is closed by the lid 25.

Here, in this embodiment, the outer cylinder 21
And the flange portion 22 is integrally formed of a damping alloy plate (damping metal plate), and before the opening portion 24 is closed by the lid portion 25, the outer cylindrical portion 21 and the cylindrical portion of the ball nut 6 are cut out from the opening portion 24. 6a is filled with a foamed resin 29 such as polystyrene foam as a sound absorbing material having a function of attenuating sound energy, and a return tube 50A attached to the cylindrical portion 6a of the ball nut 6 is attached to the foamed resin 29. It is buried.

As a result, the sound energy generated when the ball 5 circulates in the return tube 50A is attenuated by the foamed resin 29, and furthermore is damped by the damping action of the outer cylinder portion 21 made of a damping alloy plate. Low noise is achieved, and as a result, the ball screw device 20 can be suitably used in an environment where low noise and noise reduction are required. In the above embodiment, the case where the entire cylindrical portion 6a of the ball nut 6 is covered with the surrounding member is taken as an example.
May be partially covered to surround the return tube 50A.

In the above embodiment, the return tube 50A is taken as an example of a ball circulating component. However, instead of this, a ball screw having a top type, a guide plate type, an end cap type and other ball circulating components is used. The present invention may be applied to an apparatus. However, in the case of the end cap type, it is preferable to provide a space between the end face of the cylindrical portion 6a of the ball nut 6 and the lid 25, and to fill the space with a sound absorbing material.

In the above embodiment, the foamed resin is filled as the sound absorbing material. However, a gel-like substance, for example, polyisobutylene, polybutene or the like may be filled instead of the foamed resin.

[0015]

As is apparent from the above description, according to the first aspect of the present invention, the energy of the sound generated when the ball circulates in the ball circulating component can be attenuated by the sound absorbing material. The effect that it can be used suitably in the environment where low noise and noise reduction are required is obtained.

According to the second aspect of the present invention, in addition to the first aspect of the present invention, the effect of further reducing the noise can be obtained by the damping action of the damping metal plate.

[Brief description of the drawings]

FIG. 1 is a partially broken explanatory view for explaining a ball screw device which is an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a partially broken perspective view for explaining a conventional ball screw device.

[Explanation of symbols]

 2 ... screw groove 3 ... screw shaft 4 ... screw groove 5 ... ball 6 ... ball nut 20 ... ball screw device 21 ... outer cylinder part (surrounding member) 25 ... lid part (surrounding member) 29 ... foamed resin (sound absorbing material) 50A … Return tube (ball circulation part)

Claims (2)

[Claims] 1. A screw shaft having a spiral screw groove on an outer peripheral surface, a ball nut having a screw groove on the inner peripheral surface corresponding to the screw groove of the screw shaft and being loosely fitted to the screw shaft, A ball screw device comprising: a plurality of balls rotatably arranged between the two screw grooves; wherein the balls are guided by a ball circulation component attached to the ball nut to circulate, A ball screw device comprising: a surrounding member provided around the housing; and a sound absorbing material filled between the surrounding member and the ball nut. 2. The ball screw device according to claim 1, wherein a damping metal plate is used as the surrounding member.