JPS61189304A - Rotary actuator - Google Patents

Abstract

PURPOSE:To obtain a rotary actuator which has good sealing ability and is operated at a wide angle by axially pressing balls fitted in a screw and a straight flute of a casing by means of a hydraulic piston to turn the screw. CONSTITUTION:A straight flute 31 extended axially is formed on the inner periphery of a casing 3, and balls 7 are fitted in the straight flute and a spiral groove 4 of a screw disposed in the inner periphery of the casing 3. Rods 51, 61 adapted to axially press the balls are connected to hydraulic pistons 5, 6 are brought into contact with the balls 7. In this arrangement, when oil pressure works upon the hydraulic pistons, the axial working force is applied to the balls 7, and the working force is converted to turning force to be transmitted to an output shaft 42 disposed on the screw.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides linear motion of a piston operated by a fluid.
A spherical part 7 and a spiral groove 41 into which the part 7 fits
The screw 4 is used to convert the movement into rotational movement.

In the conventional system, as shown in Fig. 1, a movable piece 1 is provided in a circular sealed container, one end of which is attached to an output shaft 2, and fluid is alternately supplied and discharged into the space on both sides of the movable piece l. , the movable piece l is moved and the output shaft 2 is rotated.The disadvantage of this mechanism is that it is difficult to seal the movable piece 1 to prevent fluid leakage, and delicate control of the rotational speed of the output shaft 2 is impossible. Therefore, it is impossible to rotate more than 360 degrees.
It was ffJ Noh.

The present invention eliminates the above drawbacks, and will be explained with reference to the drawings. FIG. 2 shows a cross-sectional view of an example of the present invention. This consists of a cylinder 3, a plurality of spherical parts 7, a screw 4 that connects the helical i41 into which the spherical parts 7 fit, an output shaft 42 that is its axis, and pistons 5 and 6.
, consisting of a rod 8 connecting the pistons 5 and 6. The pistons 5 and 6 are connected by a rod 8 with a spherical part 7 sandwiched between the protrusions 51 and 61. FIG. 3 shows a cross section taken along line AA'. The inner wall of the cylinder 3 around the screw 4 is provided with a groove 31 through which the spherical part 7 passes and a groove 32 through which the rod 8 passes.

Next, this operation will be described. When fluid is pumped through the piping port 33 while discharging the fluid in the space 36, the piston 5 is pushed by the fluid and starts moving in the direction of the screw 4. At this time, since the piston 6 is also connected, it starts moving at the same time.

Due to this movement, the spherical parts 7 lined up in the groove 31 are pushed by the protrusion 51 of the piston 5 and try to move inside the groove 31. However, the spherical part 7 is connected to the helical groove 4 of the screw 4.
1, the spherical part 7 tries to move inside the spiral groove 4I, but the spherical part 7
31, the screw 4 starts to rotate, and the spherical part 7 moves forward in the spiral groove 41 and the groove 31.

Next, while discharging the fluid in the space 35, the fluid is forced into the space 36 from the piping port 34, and the pistons 5 and 6 try to move in opposite directions. Therefore, the spherical part 7 is pushed by the protrusion 61, and while the screw 4 is reversed, the spiral groove 41 and the groove 3
1. Start moving in the opposite direction. By alternately feeding fluid into the spaces 35 and 36 as described above, the rotation directions of the screw 4 and the output shaft 42 can be alternately changed and rotated. The rotation angle of the output shaft 42 is determined by the amount of movement of the pistons 5 and 6 and the pitch of the helical groove 41 of the screw 4. Therefore, by increasing the amount of movement of the pistons 5 and 6, the rotation angle of the output shaft 42 can be easily increased to 360 degrees or more.

Next, the cross-sectional view shown in FIG. 4 will be explained. This shows the mechanism set forth in claim 2. This mechanism is provided with a screw 301 for adjusting the amount of movement of the pistons 50 and 60. By adjusting the screw 301, the piston 50
By changing the amount of movement of and 60, the amount of movement of the spherical part 7 changes, and therefore the rotation angle of the screw 40 and the output shaft 421 can be changed freely.

As described above, in the rotary actuator of the present invention, the rotation angle of the output shaft can be easily increased to 360 degrees or more, and the rotation angle can be easily adjusted. Furthermore, since the piston, which is the output part, moves in a linear manner, the rotational speed of the output shaft can be easily and delicately adjusted by providing a flow control valve at the piping port and controlling the flow rate of the fluid to be discharged.

Also, since the output part is straight, it is easy to seal to prevent fluid leakage, and fourth, the area of the piston can be increased, making it possible to output high output with a small size.

[Brief explanation of drawings]

FIG. 1 shows a cross-sectional view of a conventional mechanism. FIG. 2 shows a cross-sectional view of an example of the mechanism of the present invention. FIG. 3 shows a sectional view taken along line AA' of the mechanism shown in FIG. FIG. 4 shows a sectional view of the mechanism according to claim 2.

Claims (2)

[Claims] (1) A screw 4 having a spiral groove 41 into which a spherical part 7 fits into the cylinder 3 and an output shaft 4 that is the shaft thereof
2 is provided, its output shaft 42 is rotatably supported by the cylinder 3, and the output shaft 42 is made to protrude outside the cylinder 3. Further, two movable pistons 5 and 6 are provided on both sides of the screw 4 in the cylinder 3, and the pistons 5 and 6 are connected by a rod 8, and projections 51 and 6 provided on the pistons 5 and 6 are connected.
1, a spherical part 7 aligned with the groove 31 provided in the inner wall of the cylinder 3 and fitted into the spiral groove 41 of the screw 4 is inserted. The rotary actuator configured as described above. (2) Part 30 that adjusts the amount of movement of the pistons 50 and 60
1. A rotary actuator according to claim 1, wherein the rotary actuator is provided with: 1.