JPH04131549A - Feed screw - Google Patents

Abstract

PURPOSE:To simplify the whole structure and carry out the smooth and light high-speed rotation and high-speed feeding of a feed screw shaft or a moving body by forming the inner peripheral surface, with which balls are brought into rolling contact, of the moving body fitted to the outer periphery of the feed screw shaft through balls, into a flat cylindrical face. CONSTITUTION:A ball sleeve 8 is fitted in the idling state into an outer wheel 6 with a flange 4 and a cap 5 integrally fastened to both ends thereof through needle rollers 7 disposed/held circumferentially, then a circular hole 10a for holding balls 9 is formed between the ball sleeve 8 and a feed screw shaft 1, and a retainer 10 with one end protrusion 10b locked at a cutout 4a provided at the flange 4 is fitted to form a moving body 3. The ball 9 is in rolling contact with the spiral groove 2 of the feed screw shaft 1. The friction of the ball 9 to the ball sleeve 8 can be thereby reduced so as to roll lightly, and also the rectilinear motion of the moving body in relation to the feed screw shaft 1 can be performed smoothly.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention involves fitting a movable body to the outer periphery of a screw shaft via a ball, and directing the rotational movement of the screw shaft along the screw axis of the movable body. This invention relates to a feed screw that is converted into linear motion.

[Prior Art] A conventional ball screw in which balls are circulated by a return tube is disclosed in, for example, Japanese Patent Application Laid-open No. 61-10535.
It has many drawbacks as described in Figures 9 and 10 of Publication No. 9 and the explanation thereof. Therefore, in addition to the above-mentioned publications, techniques for improving ball screws that do not require such a ball circulation mechanism are disclosed in Japanese Patent Application Laid-Open Nos. 55-78849, 56-131857, 58-109757, etc. Publications, and other Utility Model Application Publication Nos. 1983-96152 and 1986-61-
No. 139343, No. 62-194967, Utility Model Publication No. 2-
This is disclosed in publications such as No. 81953.

(Problems to be Solved by the Invention) By the way, the ball screw according to the above-mentioned improvement has a cylindrical member called a nand or movable body that is fitted to the outer periphery of the screw shaft via the spirally arranged balls. Both have multiple parallel annular grooves or spiral concave grooves (female threads) formed on the inner circumferential surface.In this way, multiple grooves are formed on the inner circumferential surface of the cylindrical member in the ball screw. To form is
This not only makes machining and assembly more troublesome and expensive, but also poses an obstacle to reducing the contact resistance of the ball.

The present invention has been made in response to the above-mentioned circumstances, and its purpose is to form a smooth cylindrical inner peripheral surface on which the balls of a movable body are fitted via the outer peripheral balls of the screw shaft. By making it a flat surface, the overall structure is simplified, and the resistance to the ball is reduced, allowing smooth and light high-speed rotation and high-speed feeding of the screw shaft or moving object, and improving the load capacity. The purpose of the present invention is to provide a feed screw with a

[Means for solving the problem] The feed screw of the present invention includes a screw shaft having a spiral groove on the outer periphery;
It consists of a moving body loosely fitted around the outer periphery of the screw shaft and a plurality of balls interposed between the two, and the moving body has a cylindrical outer ring and an axial direction relative to the outer ring.
The ball sleeve is comprised of a ball sleeve that is fitted into the outer ring so as to freely rotate in a restrained state, and a retainer that is located between the ball sleeve and the screw shaft and holds the ball. The ball rolling along the spiral groove is brought into rolling contact with the smooth inner circumferential surface, and the retainer is fixed to the outer ring in a non-rotating state.

[Function] According to the present invention, when the screw shaft is rotated with respect to the movable body, the balls roll by the helical groove of the screw shaft at the retaining position of the retainer in the movable body, and at the same time, the balls are rolled on the outer periphery of the retainer. As a result, the ball sleeve in which the balls are internally rotated (in the opposite direction to the screw shaft), and as a result, the moving body including the outer ring that locks and holds the retainer rotates in the screw shaft direction. It moves in a straight line to.

Moreover, in contrast to the above, when the movable body is moved relatively linearly along the screw shaft, the screw shaft will rotate.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 denotes a screw shaft having a spiral groove 2 formed on its outer periphery, and a cylindrical moving body 3 is loosely fitted on the outer periphery.

This movable body 3 has a ball sleeve 8 fitted into an outer ring 6 having a flange 4 and a cap 5 integrally fixed to both ends thereof, through needle rollers 7 arranged and held in the circumferential direction, so as to freely rotate.
Further, a circular hole 10a for holding the ball 9 is formed between the ball sleeve and the screw shaft l, and a protrusion 10b at one end is engaged with a notch 4a provided in the flange 4 or a retainer 10 is fitted therein. Therefore, the ball 9 is in rolling contact with the smooth inner circumferential surface of the ball sleeve 8 while being in rolling contact with the helical groove 2 of the screw shaft 1.

6a and 8a are sleeve holes provided in the outer ring 6 and ball sleeve 8, respectively, and 7a is a retaining ring for the needle roller 7.

Note that the spiral groove 2 may have a single thread as shown in the figure, but it may also have multiple threads. The figure shows an example in which the circular holes 10a of the retainer holding the balls 9 are provided in the left and right sides of the retainer in a direction along the spiral groove 2Q, respectively. It may also be formed in a spiral shape.

In the above configuration, when the screw shaft 1 is rotated, the ball 9
The ball rolls along the spiral groove 2, and the retainer 10 of the movable body 3 that holds the ball is locked to the outer ring 6 via the flange 4 by the engagement of the protrusion 10b and the notch 4a. The ball sleeve 8 in the outer ring 6 in which the balls are internally rotated by the needle rollers 7 in the opposite direction to the screw shaft 1. Therefore, the movable body 3, which is constructed by integrally incorporating the retainer 10 and the ball sleeve 8 so as not to move in the axial direction in relation to the outer ring, moves linearly in the axial direction.

[Effect of the invention] As described above, when using the feed screw according to the present invention,
The balls transferred along the spiral groove of the screw shaft while being held by the retainer in the movable body are brought into contact with the smooth inner peripheral surface of the ball sleeve which is located on the outer periphery of the retainer and is freely rotatable. As a result, the friction of the ball against the ball sleeve is reduced, allowing the ball to roll easily, and the moving body to move smoothly in a straight line relative to the screw shaft. In addition, since the ball sleeve has a smooth inner circumferential surface, the structure is simplified.
Moreover, the moving body can be easily assembled.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, with Figure 1 being a longitudinal side view and Figure 2 being a longitudinal side view.
The drawings are a sectional view of the cotton in FIG. 1 and AA, and FIG. 3 is a partially cutaway side view of the retainer. 1 is a screw shaft, 2 is a spiral groove, 3 is a moving body, 6 is an outer ring, 8 is a ball sleeve, 9 is a ball, and 10 is a retainer.

Claims (1)

[Claims] (1) Consisting of a screw shaft having a spiral groove on its outer periphery, a moving body loosely fitted to the outer periphery of the screw shaft, and a plurality of balls interposed between the two, the moving body has a cylindrical shape. a ball sleeve fitted into the outer ring so as to be freely rotatable while restraining the outer ring in the axial direction; and a retainer that is located between the ball sleeve and the screw shaft and holds the ball. It is composed of
The ball sleeve has a smooth inner circumferential surface in which the balls rolling along the spiral groove are in contact with each other, and the retainer is fixed to the outer ring in a non-rotating state. screw.