JPS6115242B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air motor used in a drive unit of an air drill or the like, and particularly to an air motor that can maximize the rotational ability of a rotor.

Conventionally, air motors have been widely used in pneumatic tools such as air drills, which rotate the rotor by supplying working air into a cylinder and applying the air pressure of the working air to rotor blades that protrude radially from inside the rotor. It is used.

By the way, in the above conventional air motor,
Supply working air into the cylinder through the air supply hole,
When the rotor is driven to rotate, if the gap between the inner circumferential surface of the cylinder and the outer circumferential surface of the rotor between the air supply hole and the exhaust hole becomes more than a predetermined distance when both are assembled, the rotor blades in front of the air supply hole will Since it protrudes further, air pressure from the air supply hole acts on this portion, applying force in the opposite direction to the rotor. In addition, the rotor blades that pass through the air supply hole and receive air pressure from the air supply hole protrude from the rotor's outer circumferential surface by an amount corresponding to the distance and become smaller, and the force that applies rotational force to the rotor is reduced by that amount. There was a drawback that the number of rotations decreased accordingly.

Furthermore, it is important to eccentrically assemble the rotor to the cylinder with a predetermined gap between the air supply hole and the exhaust hole on the inner circumferential surface of the cylinder so that the rotor blades do not protrude beyond the outer circumferential surface of the rotor. It was very difficult to raise the level.

Therefore, the present invention was proposed in order to eliminate the above-mentioned conventional drawbacks, and is designed to prevent the working air from acting on the rotor blade portion in front of the air supply hole and applying a force in the reverse direction to the rotor when the rotor rotates. The purpose of the present invention is to maximize the rotational ability of the rotor by adjusting the gap between the inner circumferential surface of the cylinder and the outer circumferential surface of the rotor.

Another object of the present invention is to make it possible to correct assembly errors when a rotor is assembled into a cylinder.

The gist of the present invention is to provide a rotor whose rotating shaft is eccentric with respect to the center of the cylinder, and an outer edge of which protrudes radially from inside the rotor and comes into sliding contact with the inner circumferential surface of the cylinder when the rotor rotates. Between the air supply hole and the exhaust hole in a rotor equipped with a plurality of rotor blades, an air supply hole that serves as a working air supply port into the cylinder, and an exhaust hole that discharges the air in the cylinder to the atmosphere. The inner circumferential surface of the cylinder is formed into an arcuate surface concentric with the outer circumferential surface of the rotor, and the portion of the cylinder where the arcuate surface is formed is pressed from the outside in the inner radial direction. The present invention is characterized in that a clearance adjustment device is provided which can variably adjust the minute gap between the inner circumferential surface and the outer circumferential surface of the rotor so that the rotor blades do not protrude beyond the outer circumferential surface of the rotor.

Hereinafter, one embodiment of the present invention will be specifically described based on the drawings.

As shown in FIGS. 1 and 2, in the cylinder 2 of the air motor 1 according to the present invention, both ends 2a and 2b of the cylinder 2 are connected to one end side of the insertion hole 4 in the motor body 3 via an annular packing 5. The main body 3 is held between an annular first end plate 6 that is fitted into the insertion hole 4 and an annular second end plate 7 that is fitted on the entrance side of the insertion hole 4. It is arranged in the insertion hole 4 of. Further, at the lower end of the cylinder 2, a plurality of (four in FIG. 2) working air are provided which communicate the inside of the cylinder 2 with an annular exhaust chamber 8 formed on the inner periphery of the fitting hole 4. Small-diameter communication holes 9, 9, . . . for discharge are formed in parallel at predetermined intervals in the longitudinal direction of the cylinder 2. The exhaust chamber 8 communicates with the atmosphere through a large-diameter communication hole 10 formed at the upper end of the main body 3 and a muffler 11 screwed into the communication hole 10.

A rotor 13 having a rotating shaft 12 eccentric to the center of the cylinder 2 is disposed within the cylinder 2 . The rear end 1 of the rotation shaft 12 of this rotor 13
2a is the inner peripheral portion 6a of the first end plate 6;
is rotatably supported by a first bearing 14 disposed on the outer side (left side in FIG. 2) of the first end plate 6, and
The front end portion 12b is rotatably supported via the inner peripheral portion 7a of the second end plate 7 by a second bearing 15 that is fitted and held within the second end plate 7. .

The rotor 13 has a plurality of (five in the figure) concave grooves 16, 16, 16, 16, 16 for fitting the rotor blades, the depth direction of which is in the direction of the center of the rotor 3.
are formed at predetermined intervals in the circumferential direction of the rotor. And, these concave groove portions 16, 16,...
...Inside there are first, second, third, fourth and fifth rotor blades 17A, 17B whose outer edge 17a is straight and whose inner edge 17b is arched.
17C, 17D, 17E are the groove portions 16, 16,...
It is arranged so as to be in contact with both side surfaces 16A, 16B, . . . of . . . and to be slidable in the radial direction of the rotor 13. Each of these blades 17A, 17B, 1
7C, 17D, 17E protrude radially from inside the grooves 16, 16, . . . as shown in FIG. 3 due to the centrifugal force when the rotor 13 rotates.
The outer edges 17a, 17a, ...... are the cylinder 2
It slides along the inner circumferential surface 2A of.

An air supply hole 18, which serves as a supply port for working air into the cylinder 2, is formed on the front end side of the main body 3, as shown in FIGS. 1 and 3, and the working air supplied from this air supply hole 18 is Second end plate 7
A first air supply air passage 19 opened in the cylinder 2 and a second air passage 19 opened in the longitudinal direction of the cylinder 2.
The air flows into the cylinder 2 through the air supply air passages 20, 20 and through the air supply port 21, which has a hemispherical cross section and is formed on the inner peripheral surface 2A of the cylinder 2.

On the other hand, an exhaust hole 22, which serves as an outlet for the compressed air in the cylinder 2, is formed on the front end side of the main body 3 so as to be adjacent to the air supply hole 18. The compressed air generated on the side of the exhaust hole 22 is passed through an exhaust port 23 with a hemispherical cross section formed on the inner circumferential surface 2A of the cylinder 2, and a first exhaust air passage 24 opened in the longitudinal direction of the cylinder 2. 24 and a second exhaust air passage 25 opened in the second end plate 7, and is discharged into the atmosphere through the exhaust hole 22.

The inner circumferential surface of the cylinder 2 between the air supply hole 18 and the exhaust hole 22 is formed into an arcuate surface 26 concentric with the outer circumferential surface 13A of the rotor 13, and the arcuate surface 26 and the outer circumferential surface of the rotor 13 13A and is opposed to each other with a minute distance A between them.

A concave portion 27 extending in the longitudinal direction of the cylinder 2 is formed on the outer circumferential portion of the cylinder 2 at the portion where the arcuate surface 26 is formed (the upper portion in FIGS. 2 and 3). In this concave portion 27, a set screw 2 is screwed into the main body 3 so as to be freely adjustable in the radial direction of the cylinder 2.
The tips 28a and 28a of the holes 8 and 28 penetrate (see FIG. 2).

The set screws 28, 28 serve to press the portion of the cylinder 2 in which the arcuate surface 26 is formed from the outside in the inner radial direction.
8, 28 (move toward the center of the cylinder)
When the cylinder 2 is pressed in the radial direction from the outside, the arcuate surface 26 of the cylinder 2 is distorted, and the arcuate surface 26 and the outer peripheral surface 13 of the rotor 13 are distorted.
A can be further reduced. In addition, in order to return the minute interval A to the original value, the set screws 28, 28 may be screwed back.

Note that parallel pins 29, 29 are arranged on the front end surface 3A of the main body 3 for positioning when the main body 3 is assembled to an air tool body (not shown).

Next, according to FIG. 3, the set screws 28, 28 are
The effects will be explained together with the operation of the air motor 1.

Working air (compressed air) is supplied from a compressor (not shown) to the air supply hole 18 and the first and second air supply air passages 1.
The air is supplied into the cylinder 2 through the air supply ports 9 and 20 and the air supply port 21. Then, the working air acts on one side of the first rotor blade 17A, and the rotor 13 rotates in the direction of arrow A in FIG. Note that when the rotor 13 rotates, the remaining second, third, fourth and fifth rotor blades 17B, 17C, 17D, 17E
The outer edges 17a, 17a, 17a, 17a abut against the inner peripheral surface 2A of the cylinder 2 due to centrifugal force and slide along the inner peripheral surface 2A. And the above first
The outer edge 17a of the rotor blade 17A is the cylinder 2.
While slidingly contacting the inner peripheral surface 2A of the small diameter communication hole 9,
After passing through the positions 9, . . . , the working air in the cylinder 2 flows into the exhaust chamber 8 from the communication holes 9, 9, . The working air that has flowed into the exhaust chamber 8 is discharged into the atmosphere through the large-diameter communication hole 10 and the muffler 11 shown in FIG.

Note that as the rotor 13 rotates,
That is, the third and fourth rotor blades 17C, 17
The air in the cylinder 2 compressed by the sliding of D is discharged into the atmosphere through the exhaust port 23, the first and second exhaust air passages 24, 25, and the exhaust hole 22.

When the rotor 13 rotates and the fifth rotor blade 17E comes to a position between the air supply port 21 and the exhaust port 23,
If the gap between the rotor 13 and the cylinder 2 is too large between the air supply port 21 and the exhaust port 23, the air pressure flowing from the air supply port 21
As shown in FIG. 5, a force is applied to the rotor blades 17E to rotate the rotor 13 in the reverse direction. However, this outflow can be prevented by threading the set screws 28, 28 and pressing the cylinder 2 from the outside in the radial direction, thereby further reducing the minute gap A. That is, once the rotor 13 is rotated,
Gradually screw the set screws 28, 28 while measuring the rotation speed of the rotor 13 with a tachometer or the like,
When the set screws 28, 28 stop screwing at the position where the rotational speed of the rotor 13 reaches its maximum limit, the outer circumferential surface 13A of the rotor 13 comes into sliding contact with the arcuate surface 26 of the cylinder 2, as schematically shown in FIG. It is in a state where it does not
In addition, a state can be obtained in which air is prevented from acting on the fifth rotor blade 17E in the rotor reverse rotation direction.

Therefore, the rotor 13 rotates at the maximum rotational speed, so that the performance of the air motor 1, such as the rotational torque, can be maximized.

In addition, the machining accuracy of the cylinder 2 and rotor 13,
Alternatively, even if the assembly accuracy of the rotor 13 to the cylinder 2 is poor and the rotational ability of the rotor 13 is reduced, the error can be corrected by screwing the set screws 28 and 28 back and forth, and the rotation of the rotor 13 is reduced. You can take the number to its maximum value.

In addition, in the above embodiment, the set screws 28, 2
8 is used, but a bolt or the like may be used as long as it presses the cylinder from the outside in the radial direction.

As described above, according to the present invention, the rotational speed of the rotor of the air motor can be adjusted to the maximum value, so that the performance of the air motor, such as the rotational torque, can be maximized.

Further, according to the present invention, the machining accuracy of parts such as cylinders and rotors can be made rough, and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of an air motor showing an embodiment of the present invention, FIG. 2 is a schematic vertical sectional view of the air motor, and FIG. 3 is a schematic front view illustrating the operation of the air motor. 4 and 5 are diagrams schematically showing how the gap between the cylinder and the rotor is adjusted. FIG. 4 shows the state after adjustment, and FIG. 5 shows the state before adjustment. 1...Air motor, 2...Cylinder, 2A...
Inner circumferential surface of cylinder, 12... Rotating shaft, 13... Rotor, 13A... Outer circumferential surface of rotor, 17A, 17
B, 17C, 17D, 17E...Rotor blade, 1
7a... Outer edge of rotor blade, 18... Air supply hole,
22... Exhaust hole, 26... Arc surface, 28, 28...
...Spot screw, A...Minute gap.

Claims (1)

[Claims] 1. A rotor whose rotating shaft is eccentric with respect to the center of the cylinder, a plurality of rotor blades whose outer edges protrude radially from inside the rotor and slide into sliding contact with the inner circumferential surface of the cylinder when the rotor rotates, and a plurality of rotor blades that extend into the cylinder. In a cylinder equipped with an air supply hole serving as a working air supply port and an exhaust hole for discharging the air in the cylinder to the atmosphere, the inner peripheral surface of the cylinder between the air supply hole and the exhaust hole is the outer periphery of the rotor. The inner circumferential surface of the cylinder and the outer circumferential surface of the rotor are formed by forming an arcuate surface concentric with the surface and pressing the portion of the cylinder where the arcuate surface is formed from the outside in the inner radial direction. An air motor characterized by being provided with a clearance adjustment device that can variably adjust the minute gap between the rotor blades so that the rotor blades do not protrude beyond the outer peripheral surface of the rotor.