JPS6044607A - Rotary actuator - Google Patents

Abstract

PURPOSE:To obtain a durable rotary actuator which ensures a large rotating angle in a small size by forming at least a line of spiral groove on the outer periphery of a rotating shaft and by making a ball-containing hole in the inner periphery of a piston to contain a ball. CONSTITUTION:A ball-containing hole 33 which opens to a through hole 31 is formed on a piston 3 and two lines of spiral groove 42 are formed on the outer periphery of a large diameter member 41 of a rotating shaft 4 which goes in the through hole 31 in the piston 3. The cross section of the spiral groove 42 is almost of a semicircular shape in order to receive a ball 6 smoothly. When a pressure liquid is supplied from a port 23 to the left chamber of the piston 3 to move the piston 3 to the right, the rotating shaft 4 turns to the X-arrow direction by the action of the spiral groove 42 and the ball 6.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a rotary actuator, and more specifically, the present invention relates to a rotary actuator, and more specifically, converts linear motion of a piston into rotational motion of a rotating shaft by the action of a ball and a spiral groove that cooperate with each other. Regarding the low reaction unique.

(b) Conventional technology A low reactuator that rotates a shaft using fluid pressure has a vane that contacts the inner circumference of the cylinder fixed to a rotating shaft that passes through the cylinder, and fluid pressure is applied to the vane to rotate the rotating shaft. Rotating vane types are common. However, with conventional vane-type low reactor actuators, (a) sealing around the vanes is difficult and internal and external leaks occur in the early stages, (b) they lack durability, and (c) frictional force increases when downsized. (b) Internal cushioning is difficult and damage due to inertial load becomes a problem; (e) Rotation angle cannot be widened and is limited to 270° at most. There was a problem.

(c) Purpose of the Invention The present invention was made in view of the problems of the conventional vane type rotary actuator, and its purpose is to prevent internal and external leakage at the initial stage and after use for a certain period of time, and to be compact. The purpose of the present invention is to obtain a row actuator that has a wide rotation angle and is more durable.

B) Structure of the Invention The first invention of the present application provides a piston within a cylinder so as to be movable only in the axial direction, and a rotary shaft passing through the piston to be rotatable.
A spiral groove with parallel stripes is formed, and a ball receiving hole is formed on the inner circumference of the piston, and a ball is provided in the ball receiving hole to fit into the spiral groove, and the linear movement of the piston is controlled by the ball and the ball. The rotary shaft is configured to be converted into a rotary shaft of the rotary shaft via a spiral groove.

In the second invention of the present application, a piston is provided in the cylinder so as to be movable only in the axial direction, and a rotating shaft passing through the piston is rotatably provided, and at least one spiral groove is formed on the outer periphery of the rotating shaft. Further, a ball receiving hole is formed in the inner circumference of the piston, a ball is provided in the ball receiving hole to enter the spiral groove, and the piston has a lubricant containing chamber whose one end communicates with the ball receiving hole. The other end of the lubricant chamber is formed to communicate with the inside of the cylinder, and the linear movement of the piston is directed to the rotation axis of the rotation shaft through the ball and the spiral groove.

O is configured to convert to (e) Examples Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1 a first embodiment of a rotary actuator according to the invention is shown. The low reactor actuator 1 of this embodiment has a cylinder tube 2 having a perfectly circular cross section.
0 and end covers 21 and 22 closing both ends of its cylinder tube, a piston 3 inserted so as to be axially movable in the cylinder 2, and an end cover 21, 22 extending through the piston 3. The end cover 21, 22 is equipped with a rotary shaft 4 rotatably supported by a bearing 5, and is provided with supply/discharge ports 23, 24, through which either of the pistons in the cylinder is connected. Fluid can be supplied to or discharged from the chamber on one side.

The piston 3 is formed with a central rotating shaft insertion hole 31 and an eccentric through hole 32 parallel to the insertion hole.
A guide rod 6 whose both ends are supported by an end cover 21 and an end cover 22 is passed through the through hole 32 through which the rotating shaft 4 passes, whereby the piston 3 rotates around the rotating shaft. It's completely blocked.

The piston 3 has a ball accommodation hole 33 that opens into the insertion hole 31.
is formed.

Two spiral grooves 42 are formed on the outer periphery of the large diameter portion 41 of the rotating shaft that enters the insertion hole 31 of the piston 3. Spiral groove 42
Its cross section is approximately semicircular in order to smoothly receive a ball, which will be described later.

A ball 7 that engages with the spiral groove 42 is located within the ball accommodation hole 33.
is mounted, and the ball is held in the accommodation hole 33 by a ball retainer 71 screwed into a radially outer screw hole 35 communicating with the ball accommodation hole.

In addition, end covers 2 that close both ends of the cylinder tube 200
1.22 are securely fixed to each other by bolts (not shown) extending between the end covers.

In the rotary actuator having the above configuration, the piston moves to the right as pressure fluid is supplied to the chamber on the left side of the piston 3 in the cylinder via the boat 23 from the illustrated state. When the piston moves to the right, the piston itself is prevented from rotating, so the rotating shaft rotates in the direction of arrow X due to the action of the helical groove 41 and the ball O. Conversely, pressure fluid is supplied to the port 24, and the piston 3 moves to the right. When it advances, the rotating shaft 4 rotates in the opposite direction.

Another embodiment of the rotary actuator according to the invention is shown in FIG.

In the low reactor 1α of this embodiment, the cylinder tube 20α and the piston 3α movably inserted therein have an elliptical cross section, which allows the rotation of the piston 3α about the rotation axis 4α. is being prevented. Therefore, the guide rod 6 of the embodiment of FIG. 1 is omitted.

Furthermore, a hole 72α penetrating in the axial direction is formed in the ball retainer 71α screwed into the screw 35α that communicates with the ball accommodation hole 33cL of the piston 3α, and the hole 72α and the screw hole 35
A lubricant 1 such as grease is filled in tL. The screw hole 71α also communicates with one chamber in the cylinder (the chamber on the left side of the piston 3a) through a notch 36α formed on the outer circumference of the piston 3α, into which pressurized fluid (particularly pressurized air) flows. When it enters the screw hole 71α, it pushes the lubricant radially inward and supplies the lubricant to the ball.

The rest of the structure is the same as the embodiment shown in FIG. 1, so a detailed explanation thereof will be omitted.

The operation of the low reactuator 1α of this embodiment is the same as that of the embodiment shown in FIG. 1 in that the rotary shaft 4α is reciprocated by the reciprocating linear movement of the piston 3α. The embodiment differs from the embodiment shown in FIG. 1 in that lubricant can be supplied to the balls when pressure fluid (particularly pressurized air) is introduced into the cylinder on the left side of the piston 3α.

Note that felt or the like impregnated with oil may be inserted into the part to be filled with grease.

Further, in both embodiments, the piston is constructed of two parts, an inner and outer part, but it may be made into one piece.

(f) Effects The rotary actuator according to the present invention can have the following effects.

(b) The rotation angle can be freely selected, and more than one rotation is possible.

becomes.

(b) Since balls are used to transmit force between the piston and the rotating shaft, the same high efficiency as a ball screw can be achieved.

(Using a ball screw is expensive) (c) Since it is a piston type, a cushion mechanism can be easily attached just like a regular cylinder.

(Picture of damage due to inertial load) Even if it is miniaturized, it remains cool, so it operates with low friction and is highly efficient.

(e) Lubricant can be automatically supplied to the balls, preventing wear.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a first embodiment of a rotary actuator according to the present invention, and FIG. 2 is a cross-sectional view of another embodiment of a rotary actuator according to the present invention. 1.1α: Rotary actuator 2.2α Niji cylinder 3.3α: Piston 33: Ball accommodation hole 4.4 (Z: Rotating shaft 42.42α: Spiral groove 6.6α: Ball Patent applicant CKD Co., Ltd. (4 others) ) Figure 2

Claims (1)

[Claims] 1. A piston is provided within the cylinder so as to be movable only in the axial direction, and a rotating shaft passing through the piston is rotatably provided, and at least one spiral groove is formed on the outer periphery of the rotating shaft. In addition, a ball accommodation hole is formed on the inner circumference of the piston,
A ball is provided in the ball receiving hole to fit into the spiral groove,
A rotary actuator characterized in that the linear motion of the piston is converted to the rotation axis of the rotation shaft via the ball and the spiral groove. 2. The rotary actuator according to claim 1, wherein the cylinder has a perfect circular cross section, and a guide rod passing through the piston is provided in the cylinder parallel to the rotation axis. 3. The rotary actuator according to claim 1, wherein the cylinder has a non-perfect circular cross section. 4. A piston is provided within the groove so that it can move only in the axial direction, and a rotating shaft passing through the piston is rotatably provided, and a small spiral groove is formed on the outer circumference of the rotating shaft. and a ball accommodation hole is formed on the inner circumference of the piston,
A ball is provided in the ball receiving hole to fit into the spiral groove,
The piston is formed with a lubricant chamber whose one end communicates with the ball receiving hole, and whose other end communicates with the inside of the cylinder, so that the linear movement of the piston is controlled through the ball and the spiral groove. A rotary actuator characterized in that the rotary actuator converts rotation into rotation of the rotary shaft.