JPH05223106A - Rotary actuator - Google Patents

Abstract

PURPOSE:To realize miniaturization of a rotary actuator by increasing retaining torque in the middle position of a stroke, facilitating adjustment of the retaining torque, stabilizing oscillating action, and facilitating control of acting speed in the rotary actuator. CONSTITUTION:A stroke middle position retaining mechanism 1 that retains an oscillating shaft 2 in the middle position of a stroke with air pressure is provided in a rotary actuator. This stroke middle position retaining mechanism 1 is provided with a pinion 12, first and second rack shafts 13a, 13b, first and second action pistons 15a, 15b, first and second return pistons 14a, 14b, and first and second stoppers 16a, 16b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary actuator, and more particularly to a technique effectively applied to a stroke intermediate position holding mechanism for holding a swing shaft at a stroke intermediate position.

[0002]

2. Description of the Related Art Rotary actuators of this type include, for example, those shown below.

That is, this rotary actuator is of a rack-and-pinion system, in which first and second pistons are fixed to both ends of a rack shaft which meshes with a pinion rotatable via a swing shaft. 1 and 2
The first and second return springs for returning the movement of the piston are provided, and the swing shaft is held at the stroke intermediate position by the urging force of the first and second return springs.

[0004]

However, in the structure of the rotary actuator described above, since the swing shaft is held at the stroke intermediate position by the urging force of the first and second return springs, the stroke intermediate There is a problem that the holding torque at the position is small and it is difficult to adjust the holding torque.

Further, since the first and second pistons are oscillated by the urging forces of the first and second return springs or the air pressure against the urging forces, the oscillating motion is There is a problem that it is unstable and it is difficult to control the operating speed.

Further, since the first and second return springs must be housed in such a structure, there is a problem in that the size of the device is increased.

An object of the present invention is to provide a rotary actuator capable of increasing the holding torque at the intermediate stroke position and facilitating the adjustment of the holding torque.

Another object of the present invention is to provide a rotary actuator capable of stabilizing the swinging motion and facilitating the control of the operating speed.

Another object of the present invention is to provide a rotary actuator which can be miniaturized.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0011]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, the rotary actuator of the present invention has a structure in which a stroke intermediate position holding mechanism for holding the swing shaft by fluid pressure is provided at the stroke intermediate position.

In this case, the stroke intermediate position holding mechanism is provided with a pinion rotatably provided via a swing shaft, first and second rack shafts which face and mesh with the pinion, and the first rack shaft. And first and second working pistons respectively provided at one ends of the first and second rack shafts to move the first and second rack shafts, and the other ends of the first and second rack shafts, respectively. First and second return pistons, which are provided to return and move the first and second rack shafts, and first and second stoppers for stopping the first and second return pistons at the reference position. The structure may be provided.

[0014]

According to the rotary actuator described above, since the intermediate stroke position holding mechanism for holding the swing shaft by fluid pressure is provided at the intermediate stroke position, the holding torque at the intermediate stroke position is increased and the holding torque is increased. Can be easily adjusted.

Further, since the intermediate stroke position holding mechanism for holding the swing shaft by the fluid pressure is provided at the intermediate stroke position, it is not necessary to store the return spring, which has been a problem in the prior art. It is possible to stabilize the rocking motion and facilitate control of the motion speed.

Further, since the intermediate stroke position holding mechanism for holding the swing shaft by the fluid pressure at the intermediate stroke position is provided, it is unnecessary to store the return spring, which has been a problem in the prior art, and the size is reduced. be able to.

Further, in the above case, the stroke intermediate position holding mechanism is provided with a pinion rotatably provided via a swing shaft, and a first pinion which is opposed to and meshes with the pinion.
And a second rack shaft, first and second working pistons respectively provided at one ends of the first and second rack shafts for moving the first and second rack shafts, and the first and second working shafts. And first and second return pistons respectively provided on the other ends of the first and second rack shafts for returning and moving the first and second rack shafts, and the first and second return pistons as reference positions. Since the structure is provided with the first and second stoppers to be stopped, in addition to the above effects, the structure can be simplified and the cost can be reduced.

[0018]

1 is a sectional view showing a rotary actuator according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line II--II of FIG. 1 showing the rotary actuator of FIG.

The rotary actuator in this embodiment is of a three-position type having a stroke of, for example, -90 ° to + 90 °, and is provided with a stroke intermediate position holding mechanism 1. The stroke intermediate position holding mechanism 1 has a swing shaft 2 Has a function of holding at a stroke intermediate position by air pressure.

Specifically, the actuator body 3 has first and second shaft holes 4a and 4b which are parallel to each other, first and second rod covers 5a and 5b, and head covers 6a and 6b. Two cylinder chambers 7a, 7b
Are formed in parallel.

The first cylinder chamber 7a is formed by communicating a first large-diameter cylinder chamber 8a and a first small-diameter cylinder chamber 9a, and the first large-diameter cylinder chamber 8a is supplied to and discharged from the first rod side. The first small diameter cylinder chamber 9a communicates with the port 10a and the first head side supply / discharge port 11a.

The second cylinder chamber 7b is formed by connecting a second large-diameter cylinder chamber 8b and a second small-diameter cylinder chamber 9b, and the second large-diameter cylinder chamber 8b is connected to the second rod-side supply / discharge. The second small-diameter cylinder chamber 9b communicates with the port 10b, and communicates with the second head-side supply / discharge port 11b.

A pinion 12 is rotatably provided at the center of the actuator body 3 via a swing shaft 2, and the pinion 12 has first and second rack shafts 13a, 1a.
3b are opposed to each other and meshed with each other.

The first and second rack shafts 13a, 1
At the left end of 3b, the first and second return pistons 14a,
14b is detachably arranged, and the first and second return pistons 14a, 14b are driven by the air pressures in the first and second large-diameter cylinder chambers 8a, 8b. Return to the right and
Also, it has a function of holding the stroke intermediate position by the second stoppers 16a and 16b.

Further, the first and second rack shafts 13
At the right end of a, 13b, the first and second working pistons 1
5a and 15b are removably arranged, and the first and second working pistons 15a and 15b are driven by the air pressure in the first and second small diameter cylinder chambers 9a and 9b. 13b is moved leftward.

The first and second return pistons 14
a and 14b, the first and second piston rods 17a,
17b is fixed, and a wear-preventing striker 28 is fitted to the tip. The first and second rod covers 5a,
5b includes first and second shock absorbers 18a, 1
8b is provided coaxially, and the first and second rods 19a and 19b thereof are the same as the piston rods 17a and 17b.
It has a function of facing b and absorbing the impact and noise at the stroke end.

A stepped hole 20 is formed along the axial direction near the outer peripheral surface of the second rack shaft 13b.
An O-ring 22, a magnet 23, a spacer 24, and a magnet pressing portion 25 are sequentially housed in a large-diameter hole 21 of 0. On the outer peripheral surface of the actuator body 3, position sensors (not shown) for detecting the position in response to magnetism from the magnet 23 are attached at positions corresponding to the three positions.

Numerals 26 and 27 are piston packings.

Next, the operation of this embodiment will be described.

FIG. 1 shows the state of the intermediate stroke position.
When the swing shaft 2 is rotated counterclockwise from this stroke intermediate position toward the stroke start end, the first small diameter cylinder chamber 9
When air is supplied to a and air in the other cylinder chamber a is discharged, the air pressure in the first small diameter cylinder chamber 9a causes the first
Since the operating piston 15a of FIG. 1 presses the first rack shaft 13a, the first rack shaft 13a and the return piston 14
a moves to the left, and the first return piston 14a moves to the first
It stops by hitting the left end of the large diameter cylinder chamber 8a or the shock absorber 18a.

With the leftward movement of the first rack shaft 13a, the swing shaft 2 rotates leftward together with the pinion 12 and stops at the stroke start end.

When the swing shaft 2 is rotated clockwise from the stroke start end and held at the stroke intermediate position, air is supplied to the first large-diameter cylinder chamber 8a and the air in the other cylinder chamber 9a is discharged. Due to the air pressure in the first large-diameter cylinder chamber 8a, the first return piston 14a moves to the first rack shaft 13
and the first stopper 16a.
It stops when it hits.

With the rightward return movement of the first rack shaft 13a, the swing shaft 2 rotates rightward together with the pinion 12 and is stopped and held at the intermediate stroke position.

When the swing shaft 2 is rotated rightward from the stroke intermediate position toward the stroke end and the swing shaft 2 is rotated leftward from the stroke end to hold the stroke intermediate position, the process is substantially the same as the above case. Thus, the swing shaft 2 can be held at the intermediate position of the stroke.

As described above, since the rocking shaft 2 can be held at the intermediate stroke position by air pressure, the holding torque at the intermediate stroke position can be increased and the holding torque can be easily adjusted.

Further, since the intermediate stroke position holding mechanism 1 for holding the swing shaft 2 by pneumatic pressure is provided at the intermediate stroke position, it is not necessary to store the return spring, which has been a problem in the prior art, so that there is no need for the three positions. Stabilizes the swinging motion of
It is possible to easily control the operation speed.

Further, since the intermediate stroke position holding mechanism 1 for holding the swing shaft 2 by pneumatic pressure is provided at the intermediate stroke position, it is not necessary to store the return spring, which has been a problem in the prior art, and the size can be reduced. Can be planned.

Further, the stroke intermediate position holding mechanism 1
Is the pinion 12 and the first and second rack shafts 13
a, 13b and the first and second working pistons 15a,
15b and the first and second return pistons 14a, 14
Since it has a structure including b and the first and second stoppers 16a and 16b, in addition to the above effects, the structure can be simplified and the cost can be reduced.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in the above-described embodiment, the case where the return piston is detachably arranged at one end of the rack shaft and the operation piston is detachably arranged at the other end of the rack shaft has been described, but the present invention is not limited to this. It is also possible to fix the working piston at the end of the shaft.

In the above description, the invention mainly made by the present inventor is applied to a rotary actuator that uses air pressure as fluid pressure, which is the field of application thereof. However, the present invention is not limited to this, and hydraulic pressure is used as fluid pressure. It can also be applied to the used rotary actuator.

[0042]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1) Since the structure is provided with a stroke intermediate position holding mechanism for holding the swing shaft by fluid pressure at the stroke intermediate position, the holding torque at the stroke intermediate position is increased and the holding torque can be easily adjusted. Can be

(2) Since the intermediate stroke position holding mechanism for holding the swing shaft by the fluid pressure is provided at the intermediate stroke position, it is not necessary to store the return spring, which has been a problem in the past. It is possible to stabilize the swinging motion between them and facilitate control of the operating speed.

(3) Since the structure for providing the intermediate stroke position holding mechanism for holding the swing shaft at the intermediate stroke position by the fluid pressure is employed, the return spring, which has been a problem in the past, is not required to be housed and the size is reduced. Can be planned.

(4) In the case of the above (1), the stroke intermediate position holding mechanism includes a pinion rotatably provided via a swing shaft and a first pinion which is engaged with the pinion so as to face each other.
And a second rack shaft, first and second working pistons respectively provided at one ends of the first and second rack shafts for moving the first and second rack shafts, and the first and second working shafts. And first and second return pistons respectively provided on the other ends of the first and second rack shafts for returning and moving the first and second rack shafts, and the first and second return pistons as reference positions. Since the structure is provided with the first and second stoppers to be stopped, in addition to the above effects, the structure can be simplified and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a rotary actuator that is an embodiment of the present invention.

2 is a II of FIG. 1 showing the rotary actuator of FIG.
FIG. 6 is a sectional view taken along line II.

[Explanation of symbols]

 1 Stroke Intermediate Position Holding Mechanism 2 Swing Shaft 3 Actuator Main Body 4a First Shaft Hole 4b Second Shaft Hole 5a First Rod Cover 5b Second Rod Cover 6a First Head Cover 6b Second Head Cover 7a First Cylinder chamber 7b second cylinder chamber 8a first large diameter cylinder chamber 8b second large diameter cylinder chamber 9a first small diameter cylinder chamber 9b second small diameter cylinder chamber 10a first rod side supply / discharge port 10b first 2 rod-side supply / discharge port 11a first head-side supply / discharge port 11b second head-side supply / discharge port 12 pinion 13a first rack shaft 13b second rack shaft 14a first return piston 14b second return Piston 15a 1st movement piston 15b 2nd movement piston 16a 1st stopper 16b 2nd stopper 17a 1st Stone rod 17b Second piston rod 18a First shock absorber 18b Second shock absorber 19a First rod 19b Second rod 20 Stepped hole 21 Large diameter hole 22 O-ring 23 Magnet 24 Spacer 25 Magnet holding part 26 Piston packing 27 Piston packing 28 Friction striker

Claims (2)

[Claims] 1. A rotary actuator comprising a stroke intermediate position holding mechanism for holding a swing shaft at a stroke intermediate position by fluid pressure. 2. The stroke intermediate position holding mechanism includes: a pinion rotatably provided via a swing shaft; first and second rack shafts that mesh with the pinion so as to face each other; and the first and second rack shafts. First and second working pistons respectively provided at one end of the second rack shaft and movably moving the first and second rack shafts, and respectively provided at the other ends of the first and second rack shafts. And the first
And first and second for moving the second rack shaft back
2. The rotary actuator according to claim 1, wherein the rotary actuator has a structure including the return piston and the first and second stoppers for stopping the first and second return pistons at the reference position.