JP2523082Y2 - Ball screw top fixing structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a ball screw, and more particularly, to means for preventing a piece fixed to an elongated hole of a ball nut from falling off.

[0002]

2. Description of the Related Art As shown in FIG. 6, a ball screw is formed between a spiral groove 1a provided on an outer peripheral surface of a screw shaft 1 and a spiral groove 2a provided on an inner peripheral surface of a ball nut 2. A plurality of balls 3 are arranged in a helical circulation path, and the rotational movement of the screw shaft 1 is converted into the linear movement of the ball nut 2 via the balls 3. The top 5 has a circulation groove 5 a on the inner surface communicating with the spiral groove 2 a of the ball nut 2, and is fixed in an oblong elongated hole 2 b formed in the ball nut 2. The circulation groove 5a of the top 5 connects the spiral circulation paths to form a series of circulation paths, and the series of circulation paths enables infinite circulation of the ball. Conventionally, the top 5 of the top 5 is fixed to the long hole 2b by providing a step 2c on the longitudinal side wall of the long hole 2b, and positioning the top 5 in the depth direction with the step 2c. This is done by filling and solidifying the adhesive 6 in the space.

[0003]

In the conventional fixing structure, the locking force of the top depends only on the adhesive force between the adhesive and the side wall of the long hole. Under many conditions, there was some anxiety about the fixed state of the frames, and the frames could fall off.

[0004] Therefore, an object of the present invention is to make the fixed state of the frame firm and to surely prevent the piece from falling out of the elongated hole.

[0005]

According to the present invention, a pair of locking grooves are formed facing each other in the depth direction of a long hole, and a fixing member having a screw hole penetrating in the depth direction is formed by the locking groove. And the top of the top is pressed by the tip of a set screw screwed into the screw hole of the fixing member to fix the top in the elongated hole.

[0006]

The fixing member has a screw hole penetrating in the depth direction of the elongated hole. The fixing member is inserted into the elongated hole from the upper surface side of the top and engaged with the locking groove. Then, a set screw is screwed into the screw hole of the fixing member, and the set screw is tightened. Then, the tip of the set screw protrudes toward the top and presses the upper surface of the top. The top is pressed against the step of the elongated hole by a set screw, and is firmly fixed in the elongated hole. On the other hand, the fixing member receives the reaction force from the upper surface of the top and firmly engages with the locking groove.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In addition, about the part and the part which explanation was omitted,
It is assumed to be substantially the same as that shown in FIG.

As shown in FIGS. 1 and 2, the elongated hole 2b of the ball nut 2 has an oval shape and penetrates from the outer peripheral surface to the inner peripheral surface of the ball nut 2. A step 2c is provided in the longitudinal direction (X direction) of the side wall of the elongated hole 2b in the depth direction, and the width between the side walls on the inner diameter side of the step 2c is reduced. A pair of locking grooves 2d is formed on the side wall of the elongated hole 2b in the width direction (Z direction) at a position on the outer diameter side of the stepped portion 2c.

FIG. 3 shows a state in which the top 5 is fixed to the elongated hole 2b. The top 5 has a shape corresponding to the elongated hole 2b, and is positioned in the depth direction by engaging with the step 2c of the elongated hole 2b. A plate-shaped fixing member 8 is mounted in a space on the upper surface of the top 5. In this embodiment, a pair of fixing members 8 are used, and each dimension W1 in the X direction is smaller than the dimension W2 in the Z direction of the elongated hole 2b. This is mainly for the convenience of mounting the fixing member 8. In other words, by arranging the fixing member 8 on the upper surface side of the top 5 and swinging it in an arbitrary direction along the paper surface, the fixing member 8 can be inserted into the locking groove 2d without being deformed. It can be engaged. Further, the edge 8a of the fixing member 8 is formed in a semicircular shape in order to avoid interference between the corner portion of the fixing member 8 and the locking groove 2d when swinging. A screw hole 8b penetrating in the depth direction is provided at the center of the fixing member 8, and a set screw 9 is screwed into the screw hole 8b. A hexagonal concave portion 9a is provided on the outer diameter side end surface of the set screw 9, and when a suitable tool is engaged with the concave portion 9a and the set screw 9 is tightened, the tip of the set screw 9 is turned to the inner diameter side. It protrudes and presses the upper surface of the top 5. Top 5 is set screw 9
, It is strongly engaged with the step 2c. On the other hand, the fixing member 8 receives a reaction force from the upper surface of the top 5 and strongly engages with the outer diameter side shoulder 2e of the locking groove 2d. In this way, the top 5 is fixed in the elongated hole 2b in a stable state.

FIG. 4 shows an embodiment in which the side wall 2f of the locking groove 2d is tapered so as to expand toward the inner diameter side. In this case, as shown in FIG. 5, the end surface 8 of the edge 8a of the fixing member 8
It is desirable that c be tapered corresponding to the side wall 2f.
When the setscrew 9 is tightened, the fixing member 8 receives the reaction force from the upper surface of the top 5 and moves to the outer diameter side, and the end surface 8c of the edge 8a.
Is strongly engaged with the side wall 2f of the locking groove 2d. In this embodiment, instead of forming the edge 8a of the fixing member 8 into a semicircular shape, the fixing member 8 has a shape in which a corner is cut off.

In the embodiment described above, the space 10 formed on the outer diameter side of the fixing member 8 may be filled with an adhesive and solidified. By doing this,
It is possible to reduce noise during ball rolling and to prevent lubricant from leaking to the outer diameter side.

[0012]

According to the present invention, since the top and the fixing member are firmly fixed in the elongated hole by tightening the set screw, the top is fixed compared to the conventional method of filling and solidifying the adhesive. Strength is significantly improved. Therefore, even when the ball screw rotates at a high speed or the like, there is no need to worry about the falling off of the frame. Further, since the top and the fixing member are fixed by tightening the set screw, a stable fixing state can be obtained regardless of the dimensional accuracy of the locking groove, the fixing member, and the like. This means that the degree of freedom of the dimensional accuracy of the fixing member and the like is large, and from this point, the present invention can be said to be advantageous in terms of cost.

[Brief description of the drawings]

FIG. 1 is a partial plan view showing an elongated hole portion of a ball nut.

FIG. 2 is a sectional view taken along line XX and ZZ in FIG.

FIGS. 3A and 3B are a partial cross-sectional view and a partial plan view showing a fixed state of a top;

FIG. 4 is a partial cross-sectional view showing another embodiment of the present invention.

FIG. 5 is a partial cross-sectional view and a partial plan view showing a fixed state of a top.

FIG. 6 is a partial sectional view showing a conventional frame fixing structure.

[Explanation of symbols]

 2 Ball nut 2a Helical groove 2b Slot 2d Lock groove 5 Frame 5a Circulation groove 8 Fixing member 8b Screw hole 9 Set screw

Claims (1)

(57) [Scope of request for utility model registration] An internal circulation type ball screw in which a circulation groove communicating with a spiral groove of a ball nut is provided on an inner surface thereof is fixed in an elongated hole of the ball nut. Are formed opposite to each other, and a fixing member having a screw hole penetrating in the depth direction is engaged with the locking groove, and a tip of a set screw screwed into the screw hole of the fixing member. A top fixing structure for a ball screw, wherein the top of the top is pressed to fix the top in the elongated hole.