JPS60231064A - Ball screw - Google Patents

Abstract

PURPOSE:To enable proper use of function as a ball screw and function as a normal sliding face according to the direction of operation. CONSTITUTION:One of both slopes connecting the top to the bottom of screw thread of the male screw 2 of a shaft 1 is made an almost shperical ball face 2a and the other slope is made an almost plane sliding face 2b. In the case of female screw 4 of a nut 3 engaging with the male screw, similar ball face 4a and sliding face 4b are provided on both sides of the screw thread, and a ball 5 is interposed between the ball face 2a and the ball face 4a. When external force is applied in the direction of the arrow mark of Fig. 3, a gap g is formed between the sliding face 2b and the sliding face 4b and when the force is applied to the opposite direction, the sliding face 2b touches the sliding face 4b, and a gap is made to generate between the ball faces 2a, 4a and the ball 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pole screw in which a pole is interposed between a male thread and a female thread so that the pole screw and the sliding surface can be used depending on the working direction.

Conventionally, commonly used pole screws do not differ depending on the direction of movement, and can normally perform pole screw movement in the same way on either side in the axial direction. However, in reality, it is sufficient to have the function of a pole screw only in the working direction, and it is not necessarily necessary to have the function of a pole screw in the return direction, and it is sometimes preferable to have resistance by a sliding surface. be.

An object of the present invention is to provide a pole screw that can function as a pole screw or as a normal sliding surface depending on the direction of work. For both female threads, one surface is a pole surface and the other surface is a sliding surface of both surfaces connecting the top and trough of the thread, and the pole surfaces and sliding surfaces of both male and female threads are made to face each other. 5. A pole is interposed between both pole surfaces, and when the shaft moves in the direction of pressing the pole against the nut, a gap is provided between the sliding surfaces to make the pole screw motion, and the shaft moves in the opposite direction. In this case, a gap is provided between the ball surface and the pole to allow sliding screw movement between the sliding surfaces.

The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a vertical sectional view of a main part showing an embodiment of the present invention, and FIG. 2 is a side view of a part thereof. Male thread 2 of shaft 1 and female thread 4 of nut 3 that meshes with it
A large number of steel pawls 5 are interposed in a line between them, and when the nut 3 is rotated to move the shaft 1 in the axial direction, the pawls 5 roll and Circulating through the circulation tube 6 is similar to a conventional pole screw. In addition, 7 is a holding fitting for the circulation tube 6,
8 indicates its mounting screw.

In the case of this embodiment, as shown in an enlarged view in FIG. 3, the male thread 2 of the shaft 1 has a substantially spherical pole face 2a on one side of the side slope connecting the top and valley of the thread. The other surface is a substantially planar sliding surface 2b. on the other hand,
As for the female thread 4 of the nut 3 that engages with the male thread 2, as shown in FIG.
Five balls are interposed between the pole surfaces 2a and 4a, with the sliding surfaces 2b and 4b facing each other, respectively.

In addition, when an external force acts in the direction in which the pole surfaces 2a and 4a press against the pole 5 as shown by the arrow in FIG. , and if the force acts in the opposite direction, the sliding surfaces 2b and 4
b are in contact with each other, and a gap corresponding to - is created between the pole surfaces 2a, 4a and the pole 5. In order to allow the pawl 5 to move through the trough of the screw by a gap g, both screws 2.4 are formed with a trough 2C14C that is flat in the axial direction and continues from the pawl surfaces 2a and 4aL.

Since the embodiment of the present invention has the above-described configuration, when the shaft 1 moves, for example, in the right direction relative to the shaft 3 as shown in FIG. 4a
Since the force acts in the direction in which the pole 5 is pressed against the pole 5, a gap g is created between the sliding surfaces 2b and 4b, and in this case, only the pole screw movement is performed.

On the other hand, when the shaft l moves in the left direction as shown in FIG. Therefore, in this case, a sliding screw movement similar to that of a normal trapezoidal screw or triangular screw is performed.

In this way, the pole screw according to the present invention functions as a pole screw in the working direction and as a normal sliding screw in the return direction, so that it can be used as a pole screw or a sliding screw depending on the working direction. is possible. Therefore, the versatility and durability of the pole screw are improved,
Another advantage is that precise polishing work can be done only on the pole surface.

Furthermore, since the pole is interposed between the side surfaces of the thread, it has high rigidity in the thrust direction, and can be effectively used in machines with large thrust loads.

[Brief explanation of the drawing]

The drawings show an embodiment of the pole screw according to the present invention, and FIG. 1 is a vertical sectional view of the main part thereof, FIG. 2 is a partially sectional side view, and FIG. 3 is a diagram showing the screw thread and the pole. FIGS. 4 and 5 are enlarged cross-sectional views showing the relationship between the pole and the thread in the working direction and the returning direction, respectively. Symbol l is shaft, 2 is male thread, 3 is nut, 4 is female thread, 5 is pole, 6 is circulation tube, 7 is presser metal fitting, 8
are mounting screws, 2a and 4a are pole surfaces, 2b and 4b are sliding surfaces, and 2c and 4c are flat surfaces. Figure 1 Collection Figure 2

Claims (1)

[Claims] 1. For both the i-screw and the female thread that engages with it, one surface is a pole surface and the other surface is a sliding surface of both surfaces connecting the top and trough of the thread, and both male and female screws are used. The pole surfaces and sliding surfaces of the screw thread are opposed to each other, and a pole is interposed between both pole surfaces, and when the shaft moves in a direction that presses the pole against the nut, there is a gap between the sliding surfaces. A pole screw is characterized in that when moving in the opposite direction, a gap is provided between the pole surfaces and the sliding screw movement is performed between sliding surfaces. 2. The pole screw according to claim 1, wherein the valley portion following the pole surface of the thread has a flat surface parallel to the axial direction.