JP2603894Y2 - Rotary actuator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary actuator.

[0002]

2. Description of the Related Art A body, a cover, a piston that can only reciprocate in a cylinder formed in the body, a shaft thereof, and an inner peripheral surface of the piston and an outer peripheral surface of the shaft are formed to face each other. The shaft includes a screw groove and a power transmission element rotatably inserted between the screw grooves, and the shaft is rotated at that position by a piston that slides by supplying and discharging pressure fluid to and from a cylinder chamber defined by the piston. The rotary actuator to be driven is already known. However, the known rotary actuator has a problem that the rotation angle of the shaft cannot be easily changed because the stroke of the piston is constant.

[0003] In addition, if the rotating shaft has backlash in the axial direction, there is a problem that accurate rotation cannot be achieved.

[0004]

A problem to be solved by the present invention is to provide a rotary actuator capable of easily changing the rotation angle of a shaft.

[0005]

In order to solve the above-mentioned problems, a rotary actuator according to the present invention comprises a body, a cover, a piston that can only reciprocate in a cylinder formed in the body, a shaft thereof, It has a screw groove formed facing the inner peripheral surface of the piston and the outer peripheral surface of the shaft, and a power transmission element rotatably inserted between these screw grooves. A rotary actuator in which a shaft is rotated at a position by a piston that slides by supply and discharge of a pressure fluid, wherein the rotary actuator includes a variable stroke cover movable in an axial direction in a cylinder chamber and an adjustment for moving the variable stroke cover. Body with knobs
Of the adjustment knob mounted so that it can
A bearing for supporting the shaft is provided at the tip and the cover .

[0006]

When the variable stroke cover is moved in the axial direction of the body by the adjustment knob, the stroke of the piston is changed, so that the rotation angle of the shaft can be changed. In addition, when the adjustment knob is advanced toward the cover, the bearing provided at the distal end presses the shaft to eliminate backlash in the axial direction, so that the shaft can be accurately rotated.

[0007]

FIG. 1 shows an embodiment of the present invention. This rotary actuator 1 includes a body 2 and a head cover 3 screwed into an opening of the body. A spline 5 is formed. An annular piston 7 reciprocating in the cylinder 4
Has an axial recess 8 on the outer peripheral surface thereof.
The piston 7 reciprocates without rotating by the balls 9 rotatably inserted between the spline 5 and the spline 5.

On the side opposite to the head cover 2, a variable stroke cover 11 is movably inserted. A guide 13 screwed to the body 2 is provided with an axial groove 12 provided on the outer peripheral surface of the variable cover 11. , The stroke variable cover 11 moves only in the axial direction without rotating. An adjusting knob 14 for moving the variable stroke cover 11 forward and backward has an outer periphery of a distal end portion screwed into the inner periphery of the variable stroke cover 11, and a knob portion 14 a is screwed to the body 2 to rotate and move the adjusting knob forward and backward. The bolt 15 penetrates airtightly. This fixing bolt 15
Is screwed with a fixing nut 16 for fixing the position of the adjustment knob 14 in the axial direction.
Rotation fixing nut 1 for fixing the rotation position of adjustment knob 14
7 is screwed.

The shaft 19 which penetrates the head cover 3 and the piston 7 in an airtight manner is provided with the head cover 3 and the adjusting knob 14.
The bearings 20 and 20 provided at the end of the shaft 7 are rotatably supported and their axial positions are restricted. The bearings 20 and 20 have the same pitch and are formed facing the inner peripheral surface of the piston 7 and the outer peripheral surface of the shaft 19. The power transmission 2 is provided between the screw grooves 21 and 21.
(Balls in the illustrated embodiment) are inserted so as to freely roll. One cylinder chamber 24a partitioned by the piston 7 communicates with a pressure fluid supply / discharge port 25 opened in the head cover 3, and a return spring 26 is provided between the piston 7 of the other cylinder chamber 24b and the variable stroke cover 11. It has been curtailed. Reference numerals 27, 27 and 2 in FIG.
Reference numerals 8 and 28 denote mounting holes and screw holes for mounting the rotary actuator 1 to a desired member.

In the above embodiment, when compressed air is supplied from the supply / discharge port 25 to the cylinder chamber 24a, the piston 7 moves to the left in the drawing, and the power transmission elements 22, which roll between the screw grooves 21, 21. When the shaft 19 rotates at that position and the air in the cylinder chamber 24a is exhausted, the piston 7 moves rightward by the urging force of the return spring 26, and the shaft 19 similarly rotates at that position in the direction opposite to the above direction. I do.

In this case, when the rotation fixing nut 17 is loosened and the adjustment knob 14 is rotated, the stroke variable cover 1 is rotated.
1 is a cylinder chamber 2 by locking the groove 12 and the guide 13.
4B, the rotation of the shaft 7 can be changed by adjusting the stroke of the piston 7. Therefore, the rotation angle of the shaft 19 can be freely changed without using another piston or shaft having a different pitch of the thread groove 21. Also,
When the fixing nut 16 is loosened and the fixing bolt 15 is rotated, the adjustment knob 14 is pressed by the fixing bolt 15 and advances toward the cover 3 without rotating.
0 can preload the shaft 19 and eliminate backlash in the axial direction of the shaft 19. Therefore, the shaft 19 rotates accurately. Although the above embodiment is a single acting type,
Of course, it can be double-acting.

[0012]

According to the rotary actuator of the present invention, the rotation angle of the shaft can be changed by moving the variable stroke cover in the axial direction. Therefore, the rotation angle of the shaft can be easily changed. In addition, a bearing is provided on an adjustment knob that moves forward and backward with respect to the body, and the shaft is pre-pressed by the advancement of the adjustment knob to eliminate backlash in the axial direction, so that the shaft rotates accurately.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of an embodiment.

FIG. 2 is a bottom view of the same.

FIG. 3 is a left side view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary actuator 2 Body 3 Head cover 4 Cylinder 7 Piston 11 Variable stroke cover 14 Adjustment knob 19 Shaft 20 Bearing 21 Screw groove 22 Power transmitter 24a, 24b Cylinder chamber

Claims (1)

(57) [Scope of request for utility model registration] 1. A body, a cover, a piston which can only reciprocate in a cylinder formed in the body, a shaft thereof, and an inner peripheral surface of the piston and an outer peripheral surface of the shaft. The shaft includes a screw groove and a power transmission element rotatably inserted between the screw grooves, and the shaft is rotated at that position by a piston that slides by supplying and discharging pressure fluid to and from a cylinder chamber defined by the piston. in a rotary actuator for said rotary actuator, a variable stroke cover axially movable cylinder chamber, and an adjustment knob for moving the variable stroke cover, mounted for forward and backward in the axial direction relative to the body Coordination
A bearing that supports the shaft is installed at the tip of the knob and the cover.
Digit, rotary actuator, characterized in that.