JPH0223891Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a rotary actuator, particularly a rotary actuator that obtains swing torque to a shaft body through a pinion meshed with a rack that is reciprocated by fluid pressure. Regarding Eta.

[Background Art] Generally, as an actuator for position control of machine tools and various automatic devices, there is a so-called rotary actuator that extracts fluid pressure energy such as compressed air as swing torque of a shaft or the like.

However, in the rotary actuator having the above structure, a shock may be generated at the swinging end due to the inertia of an external load driven by the swinging shaft. The inventor of the present invention has found that there is a drawback that a smooth rocking operation cannot be performed, for example, the external load and the shaft are damaged by the generated impact force.

[Object of the invention] An object of the invention is to provide a rotary actuator that can avoid generation of impact force at the swinging end.

Another object of the present invention is to provide a rotary actuator that can arbitrarily adjust the swing angle of a shaft body that outputs swing torque.

Still another object of the present invention is to provide a rotary actuator that can simplify piping for supplying fluid pressure.

Still another object of the present invention is to provide a rotary actuator that requires less installation space and is easy to maintain.

[Summary of the invention] The present invention is characterized in that by installing a shock absorber at the stroke end of a rack that is reciprocated by fluid pressure, the shaft is oscillated via a pinion meshed with the rack. This shock absorber prevents the generation of impact force at the ends.

[Example] FIG. 1 is a cross-sectional view of a rotary actuator that is an example of the present invention, and FIG.
FIG. 2 is a sectional view of a portion indicated by a line in the figure.

A cylinder 2 and a cylinder 3 having parallel axes in the same plane are formed inside the main body 1, and a pinion 4 and a pinion 4 extend perpendicularly to the plane and pass through the boundary between the cylinders 2 and 3.
A main shaft 5 is provided coaxially and integrally with the main shaft 5.

One end of the main shaft 5 is projected to the outside of the main body 1,
Further, the main shaft 5 is rotatably supported by a bearing metal 6 and a bearing metal 7 fitted into the main body 1 at a position where a pinion 4 integrally formed with the main shaft 5 is sandwiched.

The bearing metals 6 and 7 are configured to be held in the main body 1 by a bearing presser 8 and a bearing presser 9 that are fitted into the main body 1.

The teeth of the pinion 4 are exposed inside the cylinders 2 and 3, and linearly arranged teeth are carved on the side surface of a cylindrical member that is slidably accommodated in the axial direction of the cylinders 2 and 3. The racks 14 and 15 are meshed with each other.

A piston portion 16 and a piston portion 17 are formed at one end of the racks 14 and 15, and a fluid chamber A and a fluid chamber B are formed between the piston portions 16 and 17 and a cylinder cover 18 that closes one end of the cylinders 2 and 3. are defined respectively.

Then, by alternately applying fluid pressure such as compressed air through a pressure port 19 and a pressure port 20 formed through the cylinder cover 18 and communicating with the fluid chambers A and B, respectively, the racks 14 and 15 are The structure is such that a predetermined rocking torque is generated on the main shaft 5 via a pinion 4 meshed with racks 14 and 15 by reciprocating in opposite directions.

An O-ring 21 and an O-ring 22 are respectively attached to the portions where the cylinder cover 18 and the cylinders 2 and 3 are in close contact with each other, so that the fluid chambers A and B are kept airtight.

On the outer periphery of the piston parts 16 and 17, a piston part packing 23 and a piston part packing 2 are provided.
4 is provided, and the sliding portions between the piston portions 16 and 17 and the cylinders 2 and 3 are configured to be kept airtight.

Furthermore, a dustproof cover 25 is provided at the other end of the cylinders 2 and 3 formed in the main body 1 to prevent dust from entering into the cylinders 2 and 3 from the outside.

In this case, the dustproof covers 25 provided at the ends of the cylinders 2 and 3 are threaded with the shock absorbers S1 and S2, each having a threaded portion 26 and a threaded portion 27 formed over almost the entire length of the outer periphery of the main body. The cylinders 2 and 3 provided inside the main body 1 of the rotary actuator are provided with rods 28 and 29, respectively, which absorb the dynamic load applied in the direction of pushing into the shock absorbers S1 and S2. It is configured to protrude axially into the interior of the.

As the buffers S1 and S2, for example, the structure disclosed in Japanese Utility Model Application No. 151999/1987 filed by the present applicant can be used, but any other structure may be used.

The cylinder is driven by fluid pressure alternately applied inside the fluid chamber A or B through the pressure ports 19 or 20, and rotates the main shaft 5 in a predetermined direction via the engaged pinion 4. The rack 14 or 15, which is alternately reciprocated in the axial direction inside the housing 2 or 3, is moved toward the shock absorber S1 or S2 at the stroke end on the dust-proof cover 25 side.
The rod 28 or 29 is connected to the buffer S1 or S2.
When the rack 14 or 15 is brought into contact in the direction of pushing into the interior of the rack 14 or 15, in the stopping operation at the stroke end, that is, the stopping operation at the swinging end of the main shaft 5, due to, for example, the inertial force of an external load connected to the main shaft 5. The structure is such that the impact force caused by the swing is absorbed and the stopping operation of the swinging end of the main shaft 5 is performed smoothly.

Further, the position where the rods 28 and 29 of the shock absorbers S1 and S2 are in contact with the rack 14 or 15 in the axial direction of the shock absorber S
1 and S2 with respect to the dustproof cover 25, the desired positions are set.

Further, a locking nut 30 and a locking nut 31 are screwed into the threaded portions 26 and 27 formed on the outer periphery of the buffers S1 and S2, respectively, so that the buffers S1 and S2 are held in a predetermined position relative to the dust cover 25. After being screwed into position, the shock absorbers S1 and S2 are tightened so as to come into contact with the dustproof cover 25, thereby preventing the shock absorbers S1 and S2 from becoming dustproof due to vibrations caused by the operation of the rotary actuator, for example. It is prevented from being in a floating state with respect to the cover 25.

The operation of this embodiment will be explained below.

First, the main body 1 of the rotary actuator is attached to a predetermined device, and the pressure ports 19 and 20 are connected to a predetermined air pressure source (not shown) via a predetermined control valve mechanism (not shown). .

Next, the control valve mechanism controls the pressure port 19.
Compressed air pressure is applied alternately to the fluid chambers A and B of the cylinders 2 and 3 through the cylinders 20 and 20, and the racks 14 and 15 are reciprocated in opposite directions. A predetermined swing torque is generated at the main shaft 5, and a predetermined external load connected to the main shaft 5 is driven to perform a predetermined work.

In this case, pressure port 1 is installed inside fluid chambers A and B.
The main shaft 5 is driven by compressed air pressure applied through 9 and 20, and the pinion 4 is engaged with the main shaft 5.
The racks 14 and 15 are moved axially inside the cylinders 2 and 3 toward the end where the dustproof cover 25 is attached while rotating in a predetermined direction. Vessel S
1, S2 rods 28, 29 are connected to buffers S1, S2
The rack 14,
In the stopping operation at the stroke end of 15, that is, the stopping action at the swinging end of the main shaft 5,
For example, since the impact force caused by the inertia of an external load connected to the main shaft 5 is absorbed, the stopping operation of the main shaft 5 at the swinging end is performed smoothly.

As a result, it is possible to avoid damage to the moving body load and the main shaft 5 due to, for example, an impact force generated during a stopping operation at the swing end of the main shaft 5.

In addition, a shock absorber S is provided which absorbs the impact when the racks 14 and 15 stop at their stroke ends by coming into contact with the racks 14 and 15.
Since the abutment positions of the rods 28 and 29 of the racks 14 and 15 in the axial direction of the racks 14 and 15 can be adjusted to desired positions, the strokes of the racks 14 and 15, that is, the main shaft 5
The swing angle can be adjusted arbitrarily.

Note that the present invention is not limited to the above-mentioned embodiments; for example, the fluid for operating the rotary actuator is not limited to compressed air, but may also be a gas other than pressurized air or a liquid such as oil. Also good.

[Effects] (1) A shock absorber is installed at the stroke end of the rack that is reciprocated by a rotary actuator that generates rocking torque on the shaft through a pinion meshed with the rack that is reciprocated by fluid pressure. is installed, it is possible to avoid the generation of impact force at the stroke end of the rack, that is, the swing end of the main shaft that swings due to the reciprocating motion of the rack, and it is possible to obtain a smooth swing motion. .

(2) As a result of (1) above, damage caused by impact, such as an external load connected to the main shaft and driven, can be prevented.

(3) Since the mounting position of the shock absorber rack in the stroke direction is variable, the stroke of the rack, that is, the swing angle of the shaft body can be adjusted to a desired value.

(4) A cylinder cover that closes one end of a plurality of cylinders is centrally arranged with a plurality of pressure ports that independently supply and discharge fluid to each of the cylinders. This simplifies the routing route of the piping, and the entire piping can be simplified.

Since multiple shock absorbers are arranged in a concentrated manner on the dust-proof cover that closes one end of the cylinder, the length dimension in the axial direction of the cylinder is larger than when shock absorbers are arranged individually at both ends of the cylinder. This reduces the space required for installation, and also eliminates the need to change the working posture for each shock absorber during maintenance work, such as adjusting the screw position for the dust cover of multiple shock absorbers. This makes maintenance work easier.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a rotary actuator that is an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the portion indicated by the line - in FIG. 1... Body, 2, 3... Cylinder, 4... Pinion, 5... Main shaft (shaft body), 6, 7... Bearing metal, 8, 9... Bearing holder, 14, 15... Rack, 16 , 17... Piston part, 18... Cylinder cover, 19, 20... Pressure port, 21, 2
2... O-ring, 23, 24... Piston gasket, 25... Dust-proof cover, 26, 27... Threaded portion, 28, 29... Rod, 30, 31... Locking nut, S1, S2... buffer.

Claims (1)

[Scope of utility model registration request] A rotary actuator that generates rocking torque on a shaft body through a pinion that is meshed with a rack reciprocated by fluid pressure, the rotary actuator is arranged in parallel with the pinion in between. a plurality of cylinders provided, a plurality of racks housed in each of the cylinders and individually meshing with the pinion exposed in a part of the cylinder; and a plurality of racks each fixed to the same end of the plurality of racks. a piston; a cylinder cover that closes one end of the plurality of cylinders and forms a plurality of fluid chambers between the plurality of pistons; and a cylinder cover that is bored through the cylinder cover and communicates with each of the plurality of fluid chambers. a pressure port, a dustproof cover that closes the other end side of the plurality of cylinders, and the dustproof cover is screwed onto a position facing each of the plurality of cylinders, and is in contact with the end surface of each of the racks so as to close the other ends of the plurality of cylinders. It consists of a plurality of shock absorbers each having a rod protruding into the cylinder that regulates the stroke end, and a threaded portion is carved on the outer periphery of the shock absorber over almost the entire length, and the screwing position of the shock absorber is determined. A rotary actuator characterized in that the contact position of the rod of the shock absorber with respect to the rack in the stroke direction can be made variable by changing the position.