JPH0221522Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention mainly involves twisting multiple bare conductor portions of electric wires with their end coatings stripped before crimping, brazing, soldering, screwing, etc. An air motor is used as an example of a rotational drive source in a wire twisting machine for bundling, and is also used as a drive source in various air tools such as screwdrivers, impact wrenches, and grinders. Cut grooves that open outward along or approximately along the rotation radius direction are formed at multiple locations around the supported rotor, and pressure-receiving vanes are placed in each of these cut grooves. The present invention relates to a structural improvement of an air motor for an air tool which is fitted and held in a state where it can be moved outwardly by force.

<Prior art> In the conventional general air motor of this type, as shown in FIG.
The pressure receiving blade 04 was fitted and held in the cut groove 03 formed in the blade 2 in a freely moving state. In other words, in the non-pressure-receiving state when the rotation is stopped, the pressure-receiving vanes 04, which are stopped above the horizontal plane that includes the rotor's rotational axis, move inside the cut grooves 03 inward in the rotational radial direction due to their own weight. When the rotational speed reached a certain value or higher, the leading edge of the casing 01 moved outwardly so as to come into contact with the inner circumferential surface of the casing 01 due to centrifugal force. .

<Problems to be solved by the invention> In the conventional air motor having the above structure, when the rotation is stopped, the pressure receiving blade 04, which is located below the horizontal plane including the rotational axis, is caused to move outward due to its own weight. It should be in a state where it protrudes and moves so that its leading edge comes into contact with the inner circumferential surface of the casing 01 to receive the maximum supply air pressure, and is generally designed that way.

However, in reality, the wall thickness of the pressure receiving blade 04 and the groove width of the cut groove 03 require extremely high manufacturing precision in order to prevent rattling of the blade. Accuracy is difficult to obtain and the occurrence of precision errors is unavoidable. In addition, as the pressure receiving blade 04 is used, dust and the like may enter and adhere to the notched groove 03 of the pressure receiving blade 04.
Although the sliding resistance between the inner surface and the pressure receiving vane 04 changes, and the pressure receiving vane 04 is stopped at a position lower than the rotational axis when the rotation stops as described above, it is affected by its own weight (gravity).
It often does not protrude completely outward due to the When this happens, a state in which rotation is stopped occurs in which a minute clearance is formed between the tip edge of the pressure receiving vane 04 and the inner peripheral surface of the casing 01.
Therefore, the supply air pressure leaks from the clearance, and the actual pressure received by the blades decreases, and the speed of increase in rotation slows down accordingly. Therefore,
In particular, for work such as electric wire twisting machines, where work is carried out almost continuously hundreds to thousands of times a day, and the motor must be rotated and stopped each time, motors are required. Loss time during startup was cumulative, causing a significant drop in work efficiency and productivity.

<Means for Solving the Problems> In view of the above circumstances, an object of the present invention is to provide a motor that can significantly improve the start-up characteristics of the motor without increasing the supply air pressure.

In order to achieve the above object, the structure of the air motor for an air tool according to the present invention is such that, in the structure described in detail at the beginning, the distal end edge of each pressure-receiving vane is located on the base end side of the case even in the non-pressure-receiving state. This device is characterized by a structure in which a spring portion that is urged to move outward so as to come into elastic contact with the inner circumferential surface of the thing is integrally and continuously provided by resin molding.

<Operation> According to the air motor according to the present invention having the above-mentioned characteristic structure, even when the operation is stopped and no air pressure is supplied to the casing, the tip edge of each pressure-receiving vane remains close to the inner circumferential surface of the casing. The pressure receiving blades are in elastic contact with each other, exhibiting the maximum pressure receiving area, and the space between adjacent pressure receiving vanes in the rotational circumferential direction is a closed space.
Therefore, when air pressure is supplied into the sealed space, a pressure corresponding to the supplied air pressure times the pressure receiving area acts on each pressure receiving vane, and the rotor starts to rotate smoothly.

<Examples> Examples of the present invention will be described below in detail based on the drawings.

In FIGS. 1 to 3, reference numeral 1 denotes a cylindrical motor casing having an air release notch 1b in the peripheral wall of the tip end, and is made of aluminum. It is freely pivoted. Reference numeral 4 indicates grooves formed at five locations (four locations or six locations are acceptable) equally spaced in the circumferential direction on the circumferential portion of the rotor 2 and facing outward and opening along the rotational radial direction. It is a vane-type pressure-receiving blade that is fitted and held in a shaped cut groove 3 so as to be movable in and out in the radial direction of rotation, and is made of phenolic resin having lower wear resistance than the aluminum casing 1. The pressure receiving blade 4 is molded from resin such as (Bakelite), and the base end side of the pressure receiving blade 4 has a rotor at the bottom of the notched groove 3 when the pressure receiving blade 4 is inserted and held in the notched groove 3. It comes into contact with two points near both ends in the direction of the rotation axis, and urges the tip edge 4a of each pressure receiving blade 4 to move outward in the direction of the rotation radius so that it comes into elastic contact with the inner circumferential surface of the casing 1. An arcuate spring portion 4A is integrally molded.

Next, an example of the use of the air motor M having the above structure will be explained. As shown in FIG. The air motor M is built into the
At the tip of the rotating shaft 6 which is directly connected to the air motor M, a plurality of bare electric wires A are placed at equal intervals in the rotational circumferential direction and are brought close to each other toward the rotating shaft center by rotational centrifugal force. An electric wire in which arm fingers 7 that sandwich part a are pivotally connected in a swingable manner, and a cylindrical cap 8 that surrounds these arm fingers 7 is screwed and connected to the tip of the grip cover 5. It was used as a rotational drive source for a twisting machine. In addition to this, although not shown, it can be used as a rotational drive source for various air tools such as an air driver, an impact wrench, and a grinder.

The spring portion 4A integrally molded on the base end side of each pressure receiving blade 4 may have a substantially V-shape in side view as shown in FIG. 5, and may be made of resin material. Any material other than Bakelite (phenol resin) may be used as long as it is hard and has lower abrasion resistance than the casing constituent material such as stainless steel.

<Effects of the invention> As is clear from the detailed explanation above, when the present invention is used, (1) When rotation is stopped, each pressure receiving vane is made of its material, weight, and mutual manufacturing accuracy with the rotor side notch. Regardless of the quality of the pressure-receiving vane, the tip edge can be kept in contact with the inner surface of the casing in the same manner as when the rotational speed is above a specified rotational speed where centrifugal force is exerted, so there is no leakage of air pressure regardless of the stopping position of the pressure-receiving vane. In addition to preventing this, a smooth start-up can be achieved by ensuring the maximum pressure receiving area. By doing so, time loss during startup can be minimized, contributing to improved work efficiency and productivity.

(2) Furthermore, since there is no need to use particularly high-pressure air to improve startup, not only tools but also ancillary equipment such as compressors can be made smaller and more economical.

(3) In addition, since the pressure receiving vane, including the spring part, is an integrally molded product of resin, the cost is relatively low even if it is handled as a so-called consumable item that is replaced as it wears out. (4) Furthermore, it is much easier to assemble and replace the pressure receiving blade than when the spring and blade are separate bodies.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
Figure 1 is an enlarged partially cutaway perspective view of the main part, Figure 2 is a vertical side view of the same, Figure 3 is a vertical cross-sectional view along the line shown in Figure 2, and Figure 4 is a partially cutaway view of the tool used. FIG. 5 is an enlarged longitudinal sectional front view of the main part showing another embodiment, and FIG. 6 is an enlarged longitudinal sectional front view of the main part of the conventional one. 1 is the casing, 2 is the rotor, 3 is the cut groove, 4
is a pressure receiving vane, and 4A is a spring part.

Claims (1)

[Claims for Utility Model Registration] Cut grooves 3 that open outward in a plurality of locations around the circumference of the rotor 2 that is pivotally supported within the casing 1, along or approximately along the rotation radius direction. are formed, and pressure receiving blades 4 are formed in these cut grooves 3, respectively.
is an air motor for an air tool, which is fitted and held in a state where it can protrude outward by rotational centrifugal force, and has a tip edge 4a on the base end side of each pressure receiving blade 4 even in a non-pressure receiving state. A structure of an air motor for an air tool, characterized in that a spring portion 4A is integrally provided by resin molding and urges the spring portion to move outward so as to come into elastic contact with the inner circumferential surface of the casing 1. The structure according to claim 1, wherein the spring portion 4A is arcuate in side view. The structure according to claim 1, wherein each of the pressure receiving vanes 4 is made of phenolic resin, and the casing 1 is made of aluminum.