JP2003194180A - Ball screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball screw capable of reducing the wear of balls or the like by supplying lubricant even if it is difficult to attach an automatic oil feeder to a ball nut. <P>SOLUTION: A lubricant supply hole 17 having a lubricant inflow port 17a at one end of a ball screw shaft 11 is provided inside the ball screw shaft 11 along the axis of the ball screw shaft 11, and a number of through holes 18 for causing the lubricant supplied to the lubricant supply hole 17 to be supplied to the thread groove 12 of the ball screw shaft 11 are provided on the inner surface of the lubricant supply hole 17. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball screw used in machine tools and the like.

[0002]

2. Description of the Related Art Ball screws used in machine tools are
Generally, a large number of balls are rotatably arranged between a screw groove formed on the outer peripheral surface of a ball screw shaft and a screw groove formed on the inner peripheral surface of a ball nut. When a rotational torque around the shaft is applied to the shaft, a large number of balls roll between the ball screw shaft and the ball nut screw grooves, causing the ball nut to reciprocate in the axial direction of the ball screw shaft. Has become.

In such a ball screw, if the thread groove or the ball is worn, the positioning accuracy is deteriorated. Therefore, conventionally, in order to suppress the wear of the thread groove or the ball, grease is applied inside the ball nut. In many cases, the lubricating oil is supplied to the balls by filling or by an automatic oiling device attached to the ball nut.

[0004]

However, in particular,
With a ball screw that rotates a ball nut, it may not be possible to attach the automatic lubricator to the ball nut depending on the space around the nut and the operating environment.
In such a case, there is a problem that the lubricant runs out. The present invention has been made in view of the above problems, and an object thereof is to suppress wear of balls and the like by supplying a lubricant even when an automatic oiling device cannot be attached to a ball nut. It is to provide a ball screw that can be used.

[0005]

In order to achieve the above object, the invention of claim 1 provides a thread groove formed on an outer peripheral surface of a ball screw shaft and a thread groove formed on an inner peripheral surface of a ball nut. In a ball screw configured by rollingly arranging a large number of balls in between, a lubricant supply means for supplying a lubricant to the balls is provided inside the ball screw shaft. According to a second aspect of the invention, in the ball screw according to the first aspect, the lubricant supply means has a lubricant supply hole having a lubricant inflow port at one end of the ball screw shaft along the axial direction of the ball screw shaft. Is provided inside the ball screw shaft, and a plurality of through holes for supplying the lubricant supplied to the lubricant supply hole to the thread groove of the ball screw shaft are provided on the inner surface of the lubricant supply hole. It is characterized by

According to a third aspect of the invention, in the ball screw according to the second aspect, a lubricant supply mechanism is connected to the lubricant inflow port of the lubricant supply hole. Claim 4
The invention according to claim 2 is the ball screw according to claim 2 or 3,
The inside of the hollow hole and the lubricant supply hole is filled with a fibrous flow control material. In the inventions of claims 1 to 4, since the lubricant is automatically supplied to the thread groove of the ball screw shaft, the lubricant can be supplied even when the automatic oil supply device cannot be attached to the ball nut,
Wear of balls and the like can be suppressed. Further, in the invention of claim 4, since the lubricant oil in the lubricant supply hole and the through hole adheres to the flow control material, it is possible to prevent the lubricant oil from scattering to the outside when the ball screw shaft is rotated. Since the flow of the lubricating oil is slowed by the flow control material, the lubricating oil can be supplied little by little.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views for explaining one embodiment of the present invention. FIG. 1 is a schematic sectional view of a ball screw according to one embodiment of the present invention, and FIG. 2 shows a detailed structure of a portion A in FIG. FIG. As shown in FIG. 1, a ball screw according to an embodiment of the present invention includes a screw groove 12 formed on an outer peripheral surface of a ball screw shaft 11 and a screw groove 14 formed on an inner peripheral surface of a ball nut 13. A large number of balls 15 are rotatably arranged between them, and a large number of lubricant supply holes 17 as a lubricant supply means for supplying a lubricant to the balls 15 are provided inside the ball screw shaft 11. Through holes 18 are provided.

The lubricant supply hole 17 is formed in the axial center portion of the ball screw shaft 11 along the axial direction of the ball screw shaft 11. Inside the lubricant supply hole 17 and the through hole 18,
As shown in FIG. 2, a fibrous flow control material 19 made of felt or the like is filled. The lubricant supply hole 17 has a lubricant inlet 17a at one end of the ball screw shaft 11, and the lubricant supply mechanism 20 is provided at the lubricant inlet 17a.
Are connected. On the other hand, the through hole 18 is the ball screw shaft 1
1 is formed on the inner surface of the lubricant supply hole 17 in the radial direction, and the groove bottom clearance portion 12a (see FIG. 2) of the screw groove 12 is provided with the opening end of the through hole 18. Although not shown, the ball nut 13 has screw grooves 12, 14
A ball circulation tube is attached for returning the ball 15 that has rolled between the balls 15 to the initial position.

In such a structure, when the lubricant is supplied from the lubricant supply mechanism 20 to the lubricant supply hole 17, the lubricant supplied to the lubricant supply hole 17 is provided on the inner surface of the lubricant supply hole 17. It flows into each through hole 18, flows through these through holes 18, and flows out to the groove bottom clearance portion 12 a of the screw groove 12. Therefore, in the present embodiment, it is possible to supply the lubricant to the balls 15 incorporated between the screw groove 12 of the ball screw shaft 11 and the screw groove 14 of the ball nut 13, so that the ball nut 13 can be supplied with the lubricant. Even when the automatic oil supply device cannot be attached, the lubricant can be supplied to the thread groove 12 of the ball screw shaft 11 to suppress wear of the balls and the like.

Further, in this embodiment, the fibrous flow control material 19 is filled in the lubricant supply hole 17 and the through hole 18, and the lubricant oil in the lubricant supply hole 17 and the through hole 18 is flow controlled. Since it adheres to the material 19, it is possible to prevent the lubricating oil from scattering to the outside when the ball screw shaft 11 is rotated, and the flow of the lubricating oil is slowed by the flow control material 19, so that the lubricating oil is supplied little by little. can do. Although the lubricant supply hole 17 is provided over almost the entire length of the ball screw shaft 11 in the above-described embodiment, the lubricant supply hole 17 does not necessarily have to be provided over the entire length of the ball screw shaft 11, and the screw groove 12 is formed. The lubricant supply hole 17 may be provided only in the portion where it is provided. Further, the present invention is not limited to the above-described embodiment, and various modifications can be implemented.

[0011]

As described above, according to the first to third aspects of the present invention, even if the ball nut cannot be attached to the automatic oil supply device, the lubricant can be supplied to suppress the wear of the balls and the like. it can. According to the invention of claim 4,
In addition to the effects described above, it is possible to prevent the lubricant from scattering to the outside when the ball screw shaft is rotated, and to supply the lubricant little by little.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a ball screw according to an embodiment of the present invention.

FIG. 2 is a diagram showing a detailed structure of a portion A shown in FIG.

[Explanation of symbols]

11 Ball screw shaft 12 thread groove 13 Ball nut 14 thread groove 15 balls 17 Lubricant supply hole 18 through holes 19 Flow control material 20 Lubricant supply mechanism

Claims (4)

[Claims] 1. A ball screw having a large number of balls rollably arranged between a thread groove formed on the outer peripheral surface of a ball screw shaft and a thread groove formed on the inner peripheral surface of a ball nut. The ball screw according to claim 1, wherein a lubricant supply means for supplying a lubricant to the ball is provided inside the ball screw shaft. 2. The lubricant supply means is provided with a lubricant supply hole having a lubricant inlet at one end of the ball screw shaft inside the ball screw shaft along an axial direction of the ball screw shaft. 2. A plurality of through holes for supplying the lubricant supplied to the lubricant supply hole to the thread groove of the ball screw shaft are provided on the inner surface of the lubricant supply hole. Ball screw. 3. The ball screw according to claim 2, wherein a lubricant supply mechanism is connected to the lubricant inflow port of the lubricant supply hole. 4. The ball screw according to claim 2, wherein a fibrous flow control material is filled inside the hollow hole and the lubricant supply hole.