JPH08144701A - Air motor - Google Patents

Abstract

PURPOSE: To provide a low noise air motor which has small frictional resistance and composing materials for which are free from restriction. CONSTITUTION: The rotor of an air motor is composed of a cylindrical outer rotor 2 and an inner rotor 3 arranged in the outer rotor 2, while the outer rotor 2 and the inner rotor 3 are freely-rotatably arranged in an air motor frame 5, 6, 7 with their axes of rotation O1, O2 positioned eccentrically, and a tip end of a blade formed longer than other blades 4b among the blades which are arranged so as to be capable of coming out of/sinking into the inner rotor 3 and supported by blade-guide rings 15, 16, is inserted into a blade-fitting groove formed in the inner circumferential surface of the outer rotor 2 so that the outer rotor 2 may rotate at the same rotational speed as the inner rotor 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air motor used for an air tool such as an impact wrench and an air grinder, and more particularly to an air motor having low frictional resistance and high energy efficiency.

[0002]

2. Description of the Related Art In air motors used for air tools such as impact wrenches and air grinders,
A rotor in which a plurality of blades are freely retractable is provided rotatably in a cylinder fixed to the equipment body side, and the rotor is rotated by introducing compressed air from an air supply hole.

By the way, in the conventional air motor, when driven, a plurality of blades, which are arranged so as to be retractable in the rotor, are pressed against the inner peripheral surface of the cylinder by a centrifugal force, so that a high speed (usually 20 to 30 m / sec) is obtained. ) Will slide.

Therefore, the conventional air motor has the following problems. (1) The frictional resistance between the inner peripheral surface of the cylinder and the blade is large, which reduces the rotation speed of the rotor and deteriorates energy efficiency. (2) Friction generates frictional heat, further increasing the friction coefficient. (3) The friction causes the inner peripheral surface of the cylinder and the blades to be worn (especially, the blades are significantly worn), resulting in a decrease in the performance and life of the equipment. (4) Since it is necessary to minimize the effects of frictional heat and wear, there are restrictions on the constituent materials of the cylinder, rotor, and blades. (5) When the blades are pressed against the inner peripheral surface of the cylinder by centrifugal force and slide at high speed, large noise is generated.

[0005]

SUMMARY OF THE INVENTION The present invention solves many problems of the above-mentioned conventional air motors at once, and has low frictional resistance, no restriction on constituent materials of the air motor, and low noise. The purpose is to provide.

[0006]

In order to achieve the above object, an air motor according to the first aspect of the present invention comprises a rotor of an air motor, a cylindrical outer rotor, and an inner rotor disposed in the outer rotor. The outer rotor and the inner rotor are rotatably mounted, and the rotating shafts of both are eccentrically arranged on the air motor body. The gist is that the outer rotor and the inner rotor are rotated at the same number of rotations by being inserted into the blade fitting groove formed on the inner peripheral surface of the rotor.

In the air motor of the second aspect of the present invention, in the air motor of the first aspect of the present invention, the blade inserted into the blade fitting groove formed in the outer rotor is formed longer than the other blades, and The gist is that a blade guide ring that supports the base end and regulates the amount of protrusion of the blade is provided on either or both of the upper lid and the lower lid.

[0008]

In the air motor constructed as described above, the centrifugal force generated by the high speed rotation of the inner rotor during driving causes the tips of the blades, which are freely retractable in the inner rotor, to move to the outer rotor. It is inserted into the blade fitting groove formed on the inner peripheral surface. As a result, the outer rotor and the inner rotor, which are rotatably disposed on the air motor body, smoothly rotate at the same rotation speed at high speed. Since the outer rotor and the inner rotor rotate smoothly at the same number of revolutions at high speed, there is no energy loss due to friction when the blades slide on the inner peripheral surface of the cylinder, unlike the conventional air motor. Is improved.
Further, since frictional heat is not generated due to friction and the inner peripheral surface of the outer rotor and the blades are not worn, the performance and life of the device are improved. In addition, noise when driving the air motor is reduced.
Further, while the tips of the blades that are arranged to be retractable in the inner rotor are inserted into the blade fitting grooves formed in the inner peripheral surface of the outer rotor, that is, the outer rotor and the inner rotor are as if they were integrated. Since it is rotating at the same rotation speed at high speed, even if the air motor is suddenly loaded,
By the outer rotor acting as a flywheel and releasing the rotational energy of the outer rotor to the inner rotor side through the blades, it is possible to prevent the rotational speed of the air motor from rapidly decreasing. It is possible to reduce fluctuations in the rotation speed of the air motor.

Further, the blade inserted into the blade fitting groove formed on the outer rotor is formed longer than the other blades, and
By providing a vane guide ring on one or both of the upper lid and the lower lid that supports the base end of the vane and restricts the amount of protrusion of the vane, the tip of the vane that is freely retractable in the inner rotor is The rotor can be held in a state where it is always inserted in the blade fitting groove formed on the inner peripheral surface of the rotor, which allows the air motor to be started smoothly and the blade to slide smoothly. Therefore, the performance of the air motor can be improved.

[0010]

The present invention will be described below with reference to the illustrated embodiments. The illustrated embodiment shows an example in which the present invention is applied to a hydraulic impact wrench.

The hydraulic impact wrench has a main body case 2
High pressure air supply port 21 for introducing high pressure air to 0, an intake valve 22 for supplying and stopping high pressure air, and high pressure air from the intake valve 22 for the air motor 1 by switching the air supply side and the exhaust side. The supply switching valve 23, the air motor 1 that can be rotated in both forward and reverse directions by high-pressure air, and the hydraulic percussion torque generator 24 that is rotated by the inner rotor 3 of the air motor 1 to generate percussion torque, Except for the air motor 1, the hydraulic impact wrench has a known basic structure.

The air motor 1 comprises a rotor having a cylindrical outer rotor 2 and an inner rotor 3 arranged in the outer rotor 2, and the outer rotor 2 and the inner rotor 3 are rotatable. To
The outer rotor 2 and the inner rotor 3 are eccentrically arranged to be eccentric to each other, and the outer rotor 2 and the inner rotor 7 are arranged on the upper lid 5 and the lower lid 6 and the inner case 7 which constitute the air motor body. The child 3 and the child 3 are configured to rotate at the same number of rotations.

The inner rotor 3 is rotatably supported by an upper lid 5 and a lower lid 6 via a rolling bearing 9 about a rotation axis O2 as an axis, and a plurality of blade fitting grooves 3a are formed on its outer peripheral surface at substantially equal intervals. The blades 4a and 4b are inserted into and retracted from the blade fitting insertion groove 3a.

Blades 4a, 4b arranged on the inner rotor 3
Is supported at its base end by blade guide rings 15 and 16 provided on the upper lid 5 and the lower lid 6, and the amount of protrusion thereof is restricted. The vane guide rings 15 and 16 have an annular shape, and are provided on the upper lid 5 and the lower lid 6 so that their central axes coincide with the rotation axis O1 of the outer rotor 2.

The outer rotor 2 is attached toward the outer peripheral side by the action of the centrifugal force generated by the inner rotor 3 rotating at high speed when the air motor 1 is driven and the action of the high pressure air supplied into the outer rotor 2. The outer rotor 2 is supported by blades 4a and 4b arranged on the inner rotor 3 which is biased.
Due to the action of the high-pressure air that is supplied inside and flows between the respective members, a minute gap between the outer rotor 2 and the upper lid 5 and the lower lid 6 and a gap 8 provided between the outer rotor 2 and the case 7
Has a function as an air bearing, which allows the outer rotor 2 to be rotatably supported about the rotation axis O1. The rotation axis O1 of the outer rotor 2 and the rotation axis O2 of the inner rotor 3 are eccentrically provided. In this case, the function of the gap 8 as an air bearing can be enhanced by introducing high pressure air from a passage separately provided in the gap 8 provided between the outer rotor 2 and the case 7.

On the inner peripheral surface of the outer rotor 2, a blade fitting groove 2a is formed in which the tip of the blade 4a, which is longer than the other blade 4b of the blades 4a and 4b arranged on the inner rotor 3, is inserted. To do. When the air motor 1 is driven, the blade fitting groove 2a is
Absorbs the relative sliding of the tips of the blades 4a with respect to the inner peripheral surface of the outer rotor 2 caused by the eccentricity of the rotation axis O1 of the outer rotor 2 and the rotation axis O2 of the inner rotor 3. Has a predetermined width W for. As a result, the tips of the blades 4a arranged so as to be retractable in the inner rotor 3 can be held in a state where they are always inserted into the blade fitting grooves 2a formed in the outer rotor 2. In this embodiment,
The number of blade fitting grooves 2a formed on the inner peripheral surface of the outer rotor 2 (the number of blades 4a formed longer than the other blades 4b) was set to two with the rotation axis O1 as point symmetry. The number is not limited to one, and may be one or three or more.

In the present embodiment, the outer rotor 2
A blade guide ring 15, which forms the blade to be inserted into the blade fitting groove 2a formed in the longer than the other blades 4b, supports the base ends of the blades 4a and 4b, and restricts the protruding amount of the blades 4a and 4b. By providing 16 on the upper lid 5 and the lower lid 6, the tips of the blades 4a that are arranged so as to be retractable in the inner rotor 2 are always inserted into the blade fitting grooves 2a formed on the inner peripheral surface of the outer rotor 2. Although it is configured to be held in a closed state, it is possible that all the blades have a short length and the blade guide ring is omitted. In this case, when the air motor is driven, centrifugal force generated by the high-speed rotation of the inner rotor and the action of high-pressure air supplied into the outer rotor 2 cause the blades to be retractable in the inner rotor. Is urged toward the outer peripheral side, and the tip of any one of the plurality of blades is inserted into the blade fitting groove formed on the inner peripheral surface of the outer rotor. It is possible to obtain almost the same action and effect.

Further, in the present embodiment, the outer rotor 2
Although an air bearing is used as the bearing and a bearing is used as the bearing of the inner rotor 3, a sliding bearing or other bearings can be used as the bearing.

Further, the outer rotor 2, the inner rotor 3 and the blades 4 constituting the air motor 1 are not affected by frictional heat and abrasion as will be described later, so that the materials constituting these members are restricted. Alternatively, the outer rotor 2, the inner rotor 3, and the blades 4 can be formed of the same material, for example, a metal such as aluminum or a synthetic resin. As a result, the weight of the device can be reduced, the manufacturing cost can be reduced, and the outer rotor 2 and the inner rotor 3 can be made of a metal material in order to cope with frictional heat and wear, and the blades 4
It is not necessary to design a device with a large clearance in consideration of frictional heat and thermal expansion due to the environment in which the device is used, as in a conventional air motor configured with bakelite, which improves the accuracy of the device and improves its performance. be able to.

As in the conventional air motor, the upper lid 5 and the lower lid 6 are selectively supplied with high-pressure air by switching the switching valve 23.
11a and 11b are respectively formed, and an intermediate position between the air supply / exhaust hole 10a and the air supply / exhaust hole 10b and the air supply / exhaust hole 11a are formed.
Intermediate exhaust holes 13 and 14 are formed at intermediate positions between the air supply and exhaust holes 11b. In the present embodiment, the air supply / exhaust holes and the intermediate exhaust holes are provided in both the upper lid 5 and the lower lid 6, but only the upper lid 5 or the lower lid 6 has only the air supply / exhaust holes and the intermediate exhaust holes. It can be configured to be provided in.

The upper lid 5 and the lower lid 6 are provided with blade guide rings 15 and 16 for supporting the base ends of the blades 4a and 4b arranged on the inner rotor 3, respectively. Blade guide ring 15,1
Reference numeral 6 denotes an annular shape, which is formed separately from the upper lid 5 and the lower lid 6 and is fitted into ring-shaped grooves 5a and 5b formed in the upper lid 5 and the lower lid 6 ( (See FIGS. 5 and 6), the upper lid 5 and the lower lid 6 may be integrally formed (see FIGS. 7 and 8). In this embodiment,
Although the blade guide ring is provided on both the upper lid 5 and the lower lid 6, the blade guide ring can be configured to be provided on only one of the upper lid 5 and the lower lid 6.

Next, the air motor 1 thus constructed
The operation of will be described. The air motor 1 is driven by the air supply valve 22 and the switching valve 2 provided in the main body case 20.
3 is operated to introduce high pressure air from the high pressure air supply port 21, and supply / exhaust holes 10 provided in the upper lid 5 and the lower lid 6
It is performed by selectively supplying high pressure air to a, 10b, 11a and 11b.

When compressed air is introduced into the outer rotor 2 through any one of the air supply / exhaust holes 10a, 10b, 11a, 11b provided in the upper lid 5 and the lower lid 6, the upper lid 5 and the lower lid are mediated by the bearing 9. The inner rotor 3, which is rotatably supported by the rotary shaft O2 as an axis, rotates at high speed.

On the other hand, the outer rotor 2 has an upper lid 5 and a lower lid 6.
In addition, the blade guide ring 15 provided on the upper lid 5 and the lower lid 6 is rotatably supported with respect to the inner case 7 about the rotation axis O1 and is provided in the blade fitting groove 2a formed on the outer rotor 2. Since the base end is supported by 16, and the tips of the blades 4a that are arranged in the inner rotor 3 so as to be retractable and retractable are always inserted and held, the inner rotor 3 and the inner rotor 3 rotate smoothly at the same rotational speed at high speed. . In this case, relative rotation of the tips of the blades 4a with respect to the inner peripheral surface of the outer rotor 2 caused by the rotation shaft O1 of the outer rotor 2 and the rotation shaft O2 of the inner rotor 3 being eccentrically provided. The movement is absorbed by the width W of the blade fitting groove 2a, so that the outer rotor 2 and the inner rotor 3 can smoothly rotate at a high speed at the same rotational speed.

By the way, when the air motor 1 is driven, the outer rotor 2 and the inner rotor 3 are rotated at the same number of revolutions, so that the blades 4 come into contact with the inner peripheral surface of the outer rotor 2 at substantially fixed positions. In this state, the blade does not slide on the inner peripheral surface of the cylinder unlike the conventional air motor. Therefore, there is no energy loss due to friction when the blade slides on the inner peripheral surface of the cylinder, and many problems of the conventional air motor due to this phenomenon can be solved at once. By the way, in the conventional air motor, the friction coefficient (μ) when the blade slides on the inner peripheral surface of the cylinder is 0.1 or more, and this value is the outer rotor 2 and the inner rotor 3 of the present invention. It can be presumed to be equivalent to 20 to 100 times that when and are rotated at the same number of rotations.

Further, since the outer rotor 2 and the inner rotor 3 are integrated and rotate at a high speed at the same number of revolutions, even when the air motor 1 is suddenly loaded, the outer rotor 2 is rotated. 2 acts as a flywheel to release the rotational energy of the outer rotor 2 to the inner rotor 3 side through the blades 4a, so that the rotational speed of the air motor 1 does not suddenly decrease.

Further, since the tips of the blades 4a arranged so as to be retractable in the inner rotor 3 are always inserted into the blade fitting grooves 2a formed in the outer rotor 2, the air motor 1 is maintained. The start-up becomes smooth. In this case, the blades 4a,
By supporting the base ends of the blades 4b by the blade guide rings 15 and 16 and controlling the amount of protrusion of the blades 4a and 4b, the blades 4a and 4b slide smoothly in the blade fitting groove 3a, and The guide rings 15 and 16 have a function of preventing abnormal runout of the outer rotor 2 via the blades 4a and 4b. When the air motor 1 is driven, the blades 4a arranged on the inner rotor 3 are driven by the centrifugal force generated by the inner rotor 3 rotating at high speed and the action of the high-pressure air supplied into the outer rotor 2. 4b is urged toward the outer peripheral side. For this reason, the base ends of the blades 4a, 4b have blade guide rings 15,
No contact with 16 and no energy loss or wear due to friction.

Considering the operation of the air motor 1 as described above, in the air motor 1, the outer rotor 2 of the air motor 1 is the outer ring of the bearing, the blade guide rings 15 and 16 are the inner ring of the bearing, and the inner rotor is the inner rotor. Feathers 4 arranged in 3 freely
It can be considered that a and 4b correspond to the rollers of the bearing, respectively, and these can be regarded as integrally inseparable and constitute the same structure as the bearing device.

In the above embodiment, an air motor which can rotate in both forward and reverse directions by switching the air supply side and the exhaust side of the air motor is used, and the air motor is applied to a hydraulic impact wrench. It is also possible to configure an air motor that rotates only in one direction without switching the air supply side and the exhaust side of the air motor, and apply this to an air grinder. And the air motor of the present invention,
It can be widely applied to air grinders other than hydraulic impact wrenches and other air tools.

[0030]

According to the first aspect of the present invention, when the air motor is driven, the outer rotor and the inner rotor, which are rotatably disposed on the air motor body, are the outer rotor and the inner rotor. Since it smoothly rotates at a high speed at the same number of revolutions, there is no energy loss due to friction when the blade slides on the inner peripheral surface of the cylinder, unlike the conventional air motor, so that energy efficiency can be improved. Further, since frictional heat is not generated due to friction and the inner peripheral surface of the outer rotor and the blades are not worn, the performance and life of the device can be improved. In addition, noise when driving the air motor can be reduced. Furthermore, in a state where the outer rotor and the inner rotor are integrated,
Even if the air motor is suddenly loaded, the outer rotor acts as a flywheel, and the rotational energy of the outer rotor is transferred to the inner rotor side via the blades because it rotates at high speed at the same speed. By discharging, it is possible to prevent the rotational speed of the air motor from rapidly decreasing, and it is possible to reduce fluctuations in the rotational speed of the air motor.

Further, according to the second aspect of the present invention, the tip of the blade that is freely retractable in the inner rotor is always inserted into the blade fitting groove formed in the inner peripheral surface of the outer rotor. As a result, the air motor can be smoothly started, and the blades can slide smoothly, so that the performance of the air motor can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an air motor of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a diagram showing an outer rotor of the air motor of the present invention.

FIG. 4 is a diagram showing an inner rotor of the air motor of the present invention.

FIG. 5 is a view showing an upper lid of the air motor of the present invention.

FIG. 6 is a view showing a lower lid of the air motor of the present invention.

FIG. 7 is a diagram showing an upper lid of the air motor of the present invention.

FIG. 8 is a view showing a lower lid of the air motor of the present invention.

FIG. 9 is a diagram showing an embodiment in which the air motor of the present invention is applied to a hydraulic impact wrench.

[Explanation of symbols]

 1 Air Motor 2 Outer Rotor 3 Inner Rotor 4a Blade 4b Blade 5 Upper Lid 6 Lower Lid 7 Inner Case 8 Outer Rotor Bearing 9 Inner Rotor Bearing 15 Blade Guide Ring 16 Blade Guide Ring O1 Outer Rotor Rotation Shaft O2 Inner rotor rotation axis

Claims (2)

[Claims] 1. A rotor of an air motor comprises a cylindrical outer rotor and an inner rotor disposed inside the outer rotor,
The outer rotor and the inner rotor are rotatably mounted, and the rotation shafts of both are eccentrically arranged on the air motor body. An air motor characterized by being inserted into a blade fitting groove formed on a peripheral surface so that an outer rotor and an inner rotor rotate at the same rotational speed. 2. A blade guide ring that is inserted into a blade fitting groove formed in the outer rotor is formed longer than other blades, and a blade guide ring that supports the base end of the blade and regulates the amount of protrusion of the blade is covered. The air motor according to claim 1, wherein the air motor is provided on either one or both of the lower lids.