JPH0439450Y2 - - Google Patents

Description

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

[Background Art] Generally, as an actuator for a position control mechanism of a machine tool or various automatic equipment, 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.

In this rotary actuator, for example, a pair of racks are engaged with a single pinion at opposing positions via the pinion, and pistons are provided at both ends of each rack, and the pistons are driven by fluid pressure within a cylinder. It is conceivable that the rack be driven by a pinion to cause the rack to reciprocate and generate rocking torque on a shaft connected to the pinion.

In this case, by communicating diagonally opposite pairs of cylinders at both ends of each rack and applying fluid pressure to each pair at the same time, the racks in each pair are moved in relatively opposite directions. It is conceivable that the pinion meshed with the pair of racks be configured so that twice the torque obtained by the movement of one rack is applied to the pinion.

In addition, in order to obtain smooth movement of the rack and pinion, a predetermined amount of play is usually provided in the meshing portion of the rack and pinion, and as a result, backlash may occur during reverse movement at the end of the pinion's swing. Although this is unavoidable, it is possible to prevent the above-mentioned effects of backlash by balancing the fluid pressures acting on two sets of cylinders located diagonally to each other.

With such a rotary actuator, by selecting the rack length and pinion diameter appropriately, the desired output swing angle can be easily set, and it is also relatively easy to convert linear reciprocating motion to high-torque swing. It is practically excellent in that it can be converted into exercise.

However, in the rotary actuator having the above structure, communication ports are formed in the wall surface of the main body in order to communicate between the cylinders at both ends of the pair of racks, which are located diagonally to each other.
As a result, it is necessary to provide piping structures, etc.
The structure is complicated, and the fluid pressure source needs a complicated pressure adjustment mechanism to adjust the fluid pressure supplied to two sets of cylinders located diagonally to each other. The inventor discovered this.

[Object of the invention] An object of the invention is to provide a rotary actuator that has a simple structure and can prevent buckling at the swing end.

Another object of the present invention is to provide a rotary actuator that can prevent wear of the piston, piston packing, etc., and extend the life of the rotary actuator.

Still another object of the present invention is to provide a rotary actuator whose pistons and racks are easy to manufacture and maintain.

Still another object of the present invention is to provide a rotary actuator that can make the torque uniform during the stroke and at the end of the stroke.

[Summary of the invention] The invention consists of a main body into which a pinion fixed to one end of the shaft is inserted, a pair of cylinders provided in parallel with the pinion in between inside the main body, and a cylinder inside each cylinder. Each is accommodated in
A pair of racks made of synthetic resin that mesh with the pinion, and a pair of racks made of synthetic resin that are provided separately from each other and placed on the same end side of the pair of racks inside each of the pair of cylinders. a cylinder cover that closes one end of the cylinder and forms a plurality of fluid chambers between the pair of pistons; a pressure port that protrudes from the cylinder cover and communicates with each of the plurality of fluid chambers; It consists of a dustproof cover that closes the other end of the cylinder.
The stroke end position of one rack driven by the air pressure acting on the piston is regulated by the other rack driven via a pinion and the piston's contact with the cylinder cover. .

[Example 1] Fig. 1 is a sectional view of a rotary actuator that is an embodiment of the present invention, Fig. 2 is a plan view, and Fig. 3 is a view of the portion indicated by a line in Fig. 1. FIG.

Inside the main body 1, cylinders 2 and 3 having parallel axes in the same plane are formed, and a pinion 4 is provided perpendicularly to the plane and penetrating the boundary between the cylinders 2 and 3.

A pair of bearings 5 that are fitted into the main body 1 are provided at both ends of the pinion 4, and the pinion 4 is rotatably supported.

Furthermore, a main shaft 6 (shaft body) coaxial with the pinion 4 is formed at one end of the pinion 4 so as to protrude to the outside of the main body 1 .

The teeth of this pinion 4 are exposed inside the cylinders 2 and 3 provided in parallel, and are linearly attached to the side surfaces of cylindrical members housed in the cylinders 2 and 3 so as to be movable in the axial direction. It has a structure in which it is simultaneously engaged with a pair of racks 7 and 8 formed by forming teeth.

The linear movement of the rack 7 or 8 in the axial direction within the cylinder 2 or 3 is obtained as a swinging movement of the pinion 4.

Furthermore, at one end of the pair of racks 7 and 8,
Pistons 9 and 10 are arranged separately from the racks 7 and 8, respectively, and are connected to the cylinders 2 and 3.
Two fluid chambers are formed together with a cylinder cover 11 that closes one end of the cylinder.

Around the pistons 9 and 10, there are piston packings 12, and around the cylinders 2 and 3, respectively.
O-rings 13 are provided between the cylinder cover 11 and the cylinder cover 11 to maintain airtightness within the two fluid chambers.

Then, by applying compressed air pressure alternately to the two fluid chambers through two pressure ports 14 and 15 formed in the cylinder cover 11 and communicating with the two fluid chambers, the piston 9 or 10 is A thrust is generated, and the racks 7 or 8 with which the pistons 9 and 10 abut, respectively, are reciprocated linearly, and a swinging torque is obtained on the main shaft 6 via the pinion 4.

Further, dustproof covers 16 are provided at the ends of the cylinders 2 and 3 so as to face the cylinder cover 11, to prevent dust and foreign matter from entering the cylinders 2 and 3.

In this case, when one of the racks 7 or 8 is driven by the effect of air pressure, the other is driven via the pinion 4 in the opposite direction.

On the other hand, cylinders 2 and 3 of racks 7 and 8
Physically, the stroke within the racks is regulated by the position where the pistons 9 and 10 come into contact with the cylinder cover 11 and the position where the ends of the racks 7 and 8 come into contact with the dustproof cover 16. In the present invention, as shown in FIG.
The rack 8, which is driven to the left in the figure by the air pressure acting on the air, moves in the middle of its stroke before its end comes into contact with the dustproof cover 16 and stops.
The stop position is regulated by the action of the piston 9 provided on the driven rack 7 coming into contact with the cylinder cover 11.

The above operation is driven by air pressure acting on the piston 9 of the rack 7, and the rack 8 and the piston 1
The same applies to the case where 0 is driven via the pinion 4.

As a result, at the end of the swing, the pinion 4 is driven by the rotational force of the racks 8 and 7 urged by air pressure and the cylinder cover 11 by the racks 8 and 7.
The pinion 4 is fixed by the reaction force generated in the racks 7 and 8 that come into contact with the pinion 4, and the play that inevitably occurs due to the smooth movement of the pinion 4 and the pair of racks 7 and 8 that are simultaneously meshed with the pinion 4. This prevents data loss caused by this.

In addition, the racks 7 and 8 have pistons 9 and 10 arranged at one end of each, and are driven alternately by applying air pressure separately.
A communication port or piping structure between the cylinders for simultaneously driving the racks 7 and 8 in opposite directions is unnecessary, and the structure is simplified.

Furthermore, in the case of this embodiment, the racks 7 and 8 and the pistons 9 and 10 are each formed separately from a predetermined synthetic resin, which makes it easier to machine the parts made of metal, for example. Thus, manufacturing costs can be reduced.

The operation of this embodiment will be explained below.

First, compressed air is introduced through the pressure port 15 into a fluid chamber formed at one end of the rack 8, which is formed by the piston 10, the cylinder 3, and the cylinder cover 11.
0 in the direction of the dustproof cover 16.

At this time, the pinion 4 meshed with the rack 8 receives rotational force, a swinging torque is generated in the main shaft 6 connected to one end of the pinion 4, and a predetermined external load (not shown) connected to the main shaft 6 is generated. ) is driven, and the rack 7, which is engaged with the pinion 4 so as to face the rack 8 via the pinion 4, is driven by the rack 8.
The cylinder cover 11 is moved in the direction opposite to the rack 8, that is, in the direction of the cylinder cover 11.

At this time, the residual pressure in the air chamber between the piston 9 and the cylinder cover 11 acts on the piston 9, and the air pressure from the pressure port 15 acts on the piston 10, so the pinions 4 move in opposite directions. It will receive torque, and pinion 4 and rack 7
and 8 can be prevented from collapsing during movement.

Then, the rack 8 is further moved in the direction of the dustproof cover 16, and before the end of the rack 8 comes into contact with the dustproof cover 16 and stops, the rack 7 and the piston 9, which are driven via the pinion 4, are moved toward the cylinder cover 16. 11 and stops.

At this time, the rotational movement of the pinion 4 is stopped due to the reaction force generated in the rack 7, while the rack 8 is in the middle of its stroke and is still urged by the pressure of the compressed air.

As a result, the pinion 4 is in a fixed state, and the main shaft 6 connected to the pinion 4 is stably stationary at the swing end, and at the beginning of the subsequent rotation in the opposite direction, it is unstable due to backlash etc. Movement is prevented from occurring.

Next, by introducing compressed air into the fluid chamber composed of the piston 9, cylinder 2, and cylinder cover 11 through the pressure port 14, and releasing the compressed air pressure to the pressure port 15,
The pinion 4 is rotated in the opposite direction to the above case, a swinging torque is generated on the main shaft 6, and an external load is driven.

At this time, as in the previous case, before the rack 7 comes into contact with the dustproof cover 16 and stops, the pinion 4
The piston 10 of the rack 8 which is driven by the piston 10 contacts the cylinder cover 11, and the rack 7 is stopped in the middle of its stroke by the reaction force thereof, so that the pinion 4 is stably fixed.

In this way, the main shaft 6 that swings together with the pinion 4 is stably stopped at the swing end, and the external load driven by the main shaft 6 can operate accurately.

[Embodiment 2] FIG. 4 is a sectional view of a rotary actuator that is another embodiment of the present invention.

The second embodiment differs from the first embodiment in that stopper members 17 and 18 are provided at the portions of the cylinder cover 11 that the pistons 9 and 10 come into contact with.

That is, the stopper members 17 and 18 are screwed onto the cylinder cover 11, and the stopper members 17 and 18 are screwed onto the cylinder cover 11.
Threaded portions 19 and 2 protrude to the outside through the
By rotating 0 by a predetermined amount of rotation,
The amount of protrusion of the end surfaces that the pistons 9 and 10 abut, respectively, can be adjusted.

Further, a seal washer 21 and a nut 22 for closely fixing the seal washer 21 to the cylinder cover 11 are provided at the threaded portions of the cylinder cover 11 and the threaded portions 19 and 20, thereby maintaining the airtightness of the cylinders 2 and 3.

Thereby, by rotating the threaded portions 19 and 20 of the stopper members 17 and 18 by a desired amount in a desired direction, the cylinder cover of the driven piston 9 (rack 7) or piston 10 (rack 8) can be removed. The stopping position on the 11 side, that is, the swing angle and swing range of the pinion 4 and the main shaft 6 can be arbitrarily adjusted from the outside.

It goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made without departing from the spirit thereof.

[Effects] (1) A main body into which a pinion fixed to one end of the shaft is inserted, a pair of cylinders provided in parallel with the pinion in between inside this main body, and a cylinder housed in each cylinder. , a pair of racks made of synthetic resin that mesh with the pinion, and each rack made of synthetic resin provided separately from each other and arranged on the same end side of the pair of racks inside each of the pair of cylinders. A pair of pistons and one end of the cylinder are closed,
A cylinder cover that forms a plurality of fluid chambers between the pair of pistons, a pressure port that protrudes from the cylinder cover and communicates with each of the plurality of fluid chambers, and a dustproof cover that closes the other end of the cylinder. The stroke end position of one rack driven by the air pressure acting on the piston is regulated by the other rack driven by the pinion and the piston's contact with the cylinder cover. Therefore, due to the rotational force exerted on the pinion by one rack, which is biased by air pressure, and the reaction force generated in the other rack, which is driven via the pinion and stops when it comes into contact with the stroke start end. As a result of the pinion being stably fixed, backlash at the swinging end of the shaft driven via the pinion is prevented.

(2) As a result of (1) above, it is only necessary to provide one piston for one rack, and there is no need for a communication port or piping structure between cylinders to drive a pair of racks in opposite directions at the same time. The number of parts is small, the structure is simplified, and miniaturization is possible.

(3) By supplying and discharging air pressure from only one end, the piping ports can be concentrated at one end, simplifying the structure and operation.

(4) By centrally providing the stopper member for adjusting the stroke of the rack at one end, the structure and operation of the stroke adjustment mechanism can be simplified.

(5) By constructing the rack and piston from synthetic resin, the parts can be easily processed and manufacturing costs can be reduced.

(6) Residual pressure in the air chamber between one piston on the driven side and the cylinder cover acts on the piston,
In addition, since the air pressure from the pressure port is acting on the other piston on the drive side, the pinion receives torque in the opposite direction, and the movement between the pinion and the racks on the driven and drive sides. Can prevent breakage.

(7) Since the rack that meshes with the pinion and the piston that biases the rack in the axial direction are separate bodies, the force generated in the radial direction of the rack that meshes with the pinion causes the outer periphery of the piston to This prevents parts of the piston seal installed in the rotary actuator from sliding unevenly against the inner wall surface of the cylinder, and local wear and tear of the piston and piston seal is avoided. Lifespan can be extended.

(8) Since the rack that engages with the pinion and the piston that urges the rack in the axial direction are separate bodies, for example, the rack and piston must be connected in order to ensure the precision of engagement between the rack and pinion. Unlike the case where the piston is integrated with the piston, there is no need to increase the machining accuracy more than necessary in order to make the positional relationship between the teeth carved on the rack and the piston precise, and the piston and the rack can be manufactured easily.

(9) Since the rack that engages with the piston and the piston that urges the rack in the axial direction are completely separate, for example, during maintenance work, it is necessary to move either the rack or the piston. All that is required is replacement, which saves on maintenance parts and simplifies maintenance management work.

(10) When one of a pair of racks is driven by the corresponding piston, the other rack follows and is displaced, so the stroke of the other rack is regulated during the stroke and by the stroke end of one rack. At the end of the stroke, the swinging and static torques obtained on the main shaft via the pinion can be stabilized to a uniform value.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a rotary actuator that is an embodiment of the present invention, Fig. 2 is a plan view, Fig. 3 is a sectional view of the portion indicated by the line - in Fig. 1, and Fig. 4 is a main FIG. 3 is a sectional view of a rotary actuator according to another embodiment of the invention. 1...Body, 2, 3...Cylinder, 4...Pinion, 5...Bearing, 6...Main shaft (shaft body), 7, 8
...Rack, 9,10...Piston, 11...Cylinder cover, 12...Piston seal, 13
...O-ring, 14, 15 ...Pressure port, 16
...Dust-proof cover, 17, 18...Stopper member,
19, 20...Threaded portion, 21...Seal washer, 22...Nut.

Claims (1)

[Claims for Utility Model Registration] (1) A main body into which a pinion fixed to one end of the shaft is inserted, a pair of cylinders provided in parallel with the pinion in between inside this main body, and A pair of racks made of synthetic resin are housed inside each cylinder and mesh with the pinion, and each of the racks is provided separately, and the same end of the pair of racks is located inside each of the pair of cylinders. a pair of pistons made of synthetic resin disposed on the sides, a cylinder cover that closes one end of the cylinder and forms a plurality of fluid chambers between the pair of pistons, and a cylinder cover that protrudes from the cylinder cover, a pressure port communicating with each of the plurality of fluid chambers;
and a dustproof cover that closes the other end of the cylinder, and the stroke end position of one of the racks driven by air pressure acting on the piston is the same as that of the other rack and piston driven by the pinion. A rotary actuator characterized in that the rotary actuator is regulated by contacting the cylinder cover with the cylinder cover. (2) Utility model registration claim 1, characterized in that a stopper member whose protrusion that contacts the piston is variable in position is screwed onto the stroke starting end of at least one of the pair of racks. Rotary actuator as described.