JPS591900B2 - static air screw - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrostatic air screw that has a simple structure, extremely high precision, and is relatively easy to process.

A hydrostatic air screw that sends compressed air to the flank surface of the threaded part of the male thread of the feed screw shaft and the female thread of the nut, and forms an air bearing coating on the threaded part to enable frictionless and light central operation. be.

These static pressure air screws have an annular recess formed on the outer periphery of the nut, forming an annular chamber between the outer periphery of the nut and the inner circumferential surface of the outer cylinder fitted to the outer periphery of the nut, and opening in the flank of the nut. There is a system in which the air supply path is branched from the air supply path bored in the radial direction from the annular recess (Utility Model Publication No. 57-11).
Publication No. 69). For this reason, machining the air supply passage opening into the flank surface is complicated and difficult, and since the pressure-receiving area of the annular recess becomes large, there is a problem of air leakage due to deformation of the outer cylinder due to the supply pressure. The present invention was invented in order to solve the problems of the conventional products described above, and has a spiral groove having a V-shaped cross section with the same pitch as the female thread of the nut. A plurality of linear through-holes are drilled on the flank surface of the screw through the air supply throttle part to form an air supply path, and the gap between the outer cylinder and the helical groove, which is airtightly fitted to the outer periphery of the nut, is compressed. The purpose of the present invention is to provide a static pressure air screw that is easy to manufacture and has high precision by using an air supply path.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of application to a device for driving a table, in which a front end shaft support 2 is installed upright on a sliding table 1.
A thread 4 is formed on a feed screw shaft s which is rotatably supported by a rear end shaft support 3. Nut 7 that screws into the male thread
is fixed to a bracket 6 fixed to the table 5 by side plates 20, 21 and the like. Note that 8 is a feed screw driving motor, 9 is a gap between the crest of the male thread and the nut, and 10 is a gap between the trough of the male thread and the nut, all of which serve as an exhaust path. Further, FIGS. 2 and 3 show the nut 7 used in the embodiment of the present invention.

A helical groove 11 having the same pitch as the female thread of the nut is formed on the outer periphery of the nut. As shown in detail in FIG. 3, a plurality of straight through holes 14 are drilled from the right wall surface 12 of the helical groove to the left blank surface 13 of the nut at almost right angles and along the helical winding wire. An air supply throttle 15 is embedded near the opening of the blank, which serves as an air path. Also, a plurality of linear through holes 1 are formed along the helical winding from the left wall surface 16 at right angles to the right blank surface 17 of the nut.
8 is bored to serve as an air supply path, and an air supply throttle 19 is buried near the opening of the blank. Further, the outer cylinder 6, which is a bracket, is hermetically fitted to the outer periphery of the nut, and a thread-shaped gap P is formed between the outer cylinder 6 and the helical groove 11. Furthermore, FIG. 4 shows another embodiment of the nut of a double static air screw.

This consists of a pair of nuts 71, 72 with straight through holes 14, 18 opened on opposite sides of the blank, each nut having a flange 24, 25 formed therein. A sleeve 22, which is an outer cylinder, is interposed between the bracket 6 and the nuts 71, 72, and the bolts 26, 2
6, the nut goes to sleep 22 by holding the adjustment ring 25.
It is roughly fixed to the bracket 6. In these cases,
The gap between the blank surfaces of the nut can be adjusted. Compressed air is sent from a supply port (not shown) to the threaded gap P, and is blown out from the gap through the linear through holes 14, 15 and the throttle onto the threaded portion to form an air bearing coating.

When the drive motor 8 is operated in this state, the feed screw shaft S rotates and operates smoothly without friction due to the presence of the air bearing coating, thereby moving the nut 7 along the feed screw shaft. let
As described above, the present invention forms a helical groove 11 in the same pitch shape as the female thread of the nut on the outer periphery of the nut 7, and a plurality of linear penetrations from the helical groove to the blank surfaces 13 and 17 of the female thread of the nut. Since the holes 14 and 18 are formed, the processing of the through-holes is extremely simple, and since the through-holes can be formed almost perpendicularly to the blank surface, the performance as a static air screw can be improved.

Furthermore, since the gap formed between the outer cylinder and the helical groove 11 that are airtightly fitted around the outer periphery of the nut 7 is used as the compressed air supply path P, the pressure receiving area for the supply pressure is reduced, and the construction of seals and the like becomes easier. It has excellent effects, such as reducing the amount of

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment using the static air screw of the present invention, Fig. 2 is a front view of an embodiment of the nut of the invention, Fig. 3 is a sectional view of the same, and Fig. 4 is a cross-sectional view of the nut of the invention. FIG. 7 is a cross-sectional view of another embodiment. 4... Neji, 7... Natsuto, 9,1
0... Exhaust passage, 11... Letter-shaped helical groove, 14... Linear through hole (air supply passage), 18.
.....Linear through hole (air supply path), S ..... Feed screw shaft, P ..... Compressed air supply path.

Claims (1)

[Claims] 1. Consisting of a feed screw shaft with a male thread and a nut screwed into the male thread, compressed air is sent from the outside to the thread flank surface of the threaded part to form an air bearing coating. An air supply path is formed on the nut side, and the thread-shaped gaps formed between the crests of the male thread and the troughs of the female thread, and between the troughs of the male thread and the crests of the female thread are used as exhaust paths. For air screws, there is a V on the outer periphery of the nut with the same pitch as the female thread of the nut.
A spiral groove is formed in the shape of a letter, and a plurality of linear through holes are formed from the spiral groove to the flank surface of the female thread through the air supply throttle to form an air supply path, and the groove is airtightly fitted to the outer periphery of the nut. A static pressure air screw, characterized in that a gap formed between the spirally wound outer cylinder and the spiral groove is used as a compressed air supply path. 2. The hydrostatic air screw according to claim 1, wherein the air supply passage is formed from a wall surface of a V-shaped helical groove on the outer periphery of the nut to be substantially perpendicular to the crank surface of the nut.