JP2018003711A - Air motor of pneumatic tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air motor of a pneumatic tool used for an air impact wrench which tightens bolt and nut, in particular, by using compressed air.SOLUTION: An air motor of a pneumatic tool includes: a cylinder provided with an air intake port and an air discharge port; a rotation shaft which allows a plurality of attaching grooves to be recessed in a radial direction thereon and is provided rotatably on an inner part of the cylinder; and a plurality of blades which allow respective inner side edge parts to be fitted into the attaching grooves so as to be movably set and, at the same time, allow the respective outer side edge parts to be exposed from outer parts of the attaching grooves. Therein, straight line steps are formed on the inner side edge parts of at least half of blades, of the plurality of blades, a rectangular protruded part is provided on a middle of the straight line step, further, straight line steps corresponding to the straight line steps of the blade are formed on at least half of attachment groove, of such attachment grooves and a recessed part corresponding to the rectangular protruded part is formed on the straight line step.SELECTED DRAWING: Figure 2

Description

  The present invention particularly relates to an air motor for a pneumatic tool used in an air impact wrench that tightens bolts and nuts using compressed air.

  The existing air impact wrench tightens bolts and nuts by driving an air motor using high-pressure air as a power source. As shown in FIGS. 9 to 11, the existing air motor has a cylinder 50, a rotating shaft 60, and a plurality of blades 70, and the cylinder 50 includes an air inlet 51 and an air outlet 52. The air inlet 51 is connected to an air pressure source, and the rotary shaft 60 is installed in the cylinder 50 so as to be rotatable eccentrically away from the center of the cylinder 50, and a plurality of mounting grooves 62 are provided along the radial direction on the outer peripheral surface. The blade 70 is movably mounted in the mounting groove 62, and when high-pressure air enters the cylinder 50 through the air inlet 51, the blade 70 is rotated to rotate the rotating shaft 60 to generate power. generate.

JP 2008-183630 A

  Since the inner edge portion 72 of the existing blade 70 has an arc shape, the bottom portion 622 of the mounting groove 62 of the rotating shaft 60 is also formed in an arc shape. With this configuration, the portion near the axis of the rotating shaft 60 becomes thin, and the load for operating the air motor also increases. In addition, when the portion near the axis of the rotating shaft 60 becomes thin, the structural strength is weakened and is easily damaged, so that the service life is shortened.

  The existing air motor includes six blades 70 and the inside of the cylinder 50 is partitioned into six chambers, thereby generating sufficient torque to drive the rotary shaft 60 and the work tool. Ensure structural strength. However, since the chamber inside the cylinder 50 has a considerable volume, high pressure air for rotating the rotary shaft 60 is considerably required, leading to waste of high pressure air and providing only a predetermined torque.

  On the other hand, by increasing the number of blades 70 and increasing the number of chambers and reducing the consumption of high-pressure air, the torque from the air motor can be increased, but there are many portions near the axis of the rotating shaft 60. Since the blade 70 becomes thinner, the structural strength of the rotating shaft 60 is weakened and it is difficult to withstand a high load, so the service life is shortened.

  The pneumatic motor of the pneumatic tool of the present invention is provided with an air inlet and an air outlet, and a cylinder and a plurality of mounting grooves are recessed along the radial direction, and are rotatably installed inside the cylinder. The rotating shaft has a plurality of blades whose inner edges are fitted into the mounting grooves so that they are movably installed in the mounting grooves, and whose outer edges are exposed from the outside of the mounting grooves. In these blades, a linear step is formed at the inner edge of at least half of the blades, a rectangular protrusion is provided in the middle of the linear step, and at least half of the mounting grooves are mounted. A linear step corresponding to the linear step of the blade is formed in the groove, and a concave portion corresponding to the rectangular convex portion is formed in the linear step.

  In such an air motor of a pneumatic tool, it is preferable that at least six blades are installed on the rotating shaft.

  In such an air motor for a pneumatic tool, it is preferable that at least 12 blades are installed on the rotating shaft.

  In such an air motor of a pneumatic tool, it is preferable that the length of the rectangular convex portion in the blade having the linear step is shorter than one third of the length of the blade.

  In the air motor of such a pneumatic tool, it is preferable that the number of blades having the linear stage is half of the number of all blades.

  In such an air motor for a pneumatic tool, it is preferable that the blades having the linear steps and the blades not having the linear steps are alternately formed.

  In the air motor of the pneumatic tool, it is preferable that a bottom portion of the mounting groove not having the linear step is an arc-shaped concave portion, and an inner edge portion of the blade not having the linear step is an arc-shaped concave portion.

  In the air motor of such a pneumatic tool, it is preferable that the rotating shaft is installed in the cylinder in an eccentric state.

The pneumatic motor of the pneumatic tool according to the present invention can reduce the consumption of high-pressure air by increasing the number of chambers inside the cylinder and reducing the demand for high-pressure air inside each chamber. The amount of air discharged from the air discharge port can also be reduced.
As described above, the air motor of the present invention reduces the consumption amount of high-pressure air and efficiently uses high-pressure air to rotate the blade and rotate the rotating shaft to increase the torque from the air motor. The efficacy of can be improved.

It is a perspective view of the air motor of the pneumatic tool which concerns on this invention. It is a disassembled perspective view of the 1st Example of the air motor of the pneumatic tool which concerns on this invention. It is front sectional drawing of the 1st Example of the air motor of the pneumatic tool which concerns on this invention. It is front sectional drawing of the 2nd Example of the air motor of the pneumatic tool which concerns on this invention. It is side surface sectional drawing of the 2nd Example of the air motor of the pneumatic tool which concerns on this invention. It is sectional drawing of the AA line of FIG. It is sectional drawing of the BB line of FIG. It is side surface sectional drawing of the 3rd Example of the air motor of the pneumatic tool which concerns on this invention. It is a disassembled perspective view of the existing air motor. It is side surface sectional drawing of the existing air motor. It is front sectional drawing of the existing air motor.

As shown in FIGS. 1 and 2, the pneumatic motor of the pneumatic tool according to the invention includes a cylinder 10, a rotating shaft 20, and a plurality of blades 30.
The cylinder 10 includes an air inlet 11 and an air outlet 12. The rotary shaft 20 is rotatably installed in the cylinder 10 in an eccentric state or a coaxial state, and has a plurality of mounting grooves 22 on the outer peripheral surface. Is recessed along the radial direction. Each blade 30 is movably installed in the mounting groove 22, and its inner edge is fitted into the mounting groove 22, and its outer edge is exposed from the outside of the mounting groove 22. Among them, a straight linear step 32 is formed at the inner edge thereof, and a rectangular convex portion 34 is provided in the middle of the linear step 32, and the length of the rectangular convex portion 34 is three times the length of the blade 30. Shorter than 1.
Further, a linear step 222 corresponding to the shape of the blade 30 is formed at a location corresponding to the linear step 32 in the mounting groove 22, and the rectangular convex portion 34 is received at a location corresponding to the rectangular convex portion 34. A rectangular recess 224 that can be formed is formed.

As shown in FIGS. 5 to 7, the rotary shaft 20 maintains a portion near the axis of the rotary shaft 20 at a predetermined thickness by forming a linear step 222 in each mounting groove 22. The mounting groove 22 of the rotary shaft 20 is slightly thinned in the vicinity of the shaft center by forming the concave portion 224. However, since the concave portion 224 has linear steps 222 on both sides, it can be maintained at a predetermined thickness. Therefore, the structural strength of the rotating shaft 20 can be ensured.
Further, according to this structure, the structural strength of the rotating shaft 20 is not weakened even if the number of the mounting grooves 22 and the number of the blades 30 are increased, and usually 10 or 12 mounting grooves 22 and the blades 30 are installed. Better.
Moreover, as shown in FIG. 4, according to the above structure, the rotating shaft 20 can always maintain a predetermined structural strength.

  The pneumatic motor of the pneumatic tool according to the present invention reduces the consumption of high-pressure air by increasing the number of chambers inside the cylinder 10 and reducing the demand for high-pressure air inside each chamber, resulting in air The amount of air discharged from the discharge port 12 can also be reduced. As described above, the air motor of the present invention reduces the amount of consumption of high-pressure air, and increases the torque from the air motor by rotating the blade 30 by rotating the blade 30 efficiently using high-pressure air. Thus, the effect of the air motor can be improved.

  As shown in FIG. 8, the bottom of some of the mounting grooves 22 on the rotating shaft 20 is a linear step 222 and the bottom of the other part of the mounting grooves 22 </ b> A is an arc-shaped recess, so that according to actual demand. The mounting grooves 22, 22A can each be combined with a corresponding linear step 32 or blade 30 having an arcuate recess. Of these, the number of the mounting grooves 22 having the linear step 222 is preferably half the number of all the mounting grooves 22 and 22A, and the mounting groove 22 having the linear step 222 and the mounting groove having an arcuate recess. 22A is preferably formed alternately.

DESCRIPTION OF SYMBOLS 10 Cylinder 11 Air inlet 12 Air outlet 20 Rotating shaft 22 Mounting groove 222 Linear step 224 Rectangular recessed part 30 Blade 32 Linear step 34 Rectangular convex part 50 Cylinder 51 Air inlet 52 Air outlet 60 Rotary shaft 62 Mounting groove 622 Bottom 70 Blade 72 inner edge

Claims (9)

A cylinder having an air inlet and an air outlet;
A plurality of mounting grooves are recessed along the radial direction, and a rotating shaft that is rotatably installed inside the cylinder;
An air motor for a pneumatic tool having a plurality of blades, the inner edges of which are fitted in the mounting grooves so that they are movably installed in the mounting grooves, and the outer edges thereof are exposed from the outside of the mounting grooves. There,
Among these blades, a linear step is formed at the inner edge of at least half of the blades, and a rectangular convex portion is provided in the middle of the linear step,
Among these mounting grooves, at least half of the mounting grooves are formed with a linear step corresponding to the linear step of the blade, and a concave portion corresponding to the rectangular convex portion is formed in the linear step,
Air motor for pneumatic tools.   The pneumatic motor for a pneumatic tool according to claim 1, wherein at least six blades are installed on the rotating shaft.   The air motor for a pneumatic tool according to claim 2, wherein at least 12 blades are installed on the rotating shaft.   The pneumatic motor for a pneumatic tool according to any one of claims 1 to 3, wherein the length of the rectangular convex portion in the blade having the linear step is shorter than one third of the length of the blade. .   5. The pneumatic motor for a pneumatic tool according to claim 4, wherein the number of blades having the linear stage is half of the number of all blades.   6. The air motor for a pneumatic tool according to claim 5, wherein the blade having the linear step and the blade not having the linear step are alternately formed.   The pneumatic motor for a pneumatic tool according to claim 5 or 6, wherein a bottom portion of the mounting groove not having the linear step is an arc-shaped concave portion, and an inner edge portion of the blade not having the linear step is an arc-shaped concave portion. .   The bottom part in the attachment groove | channel which does not have the said linear step is an arc-shaped recessed part, and the inner edge part in the braid | blade which does not have the said linear step is an arc-shaped recessed part, The Claim 1 characterized by the above-mentioned. Air motor for pneumatic tools.   The pneumatic motor for a pneumatic tool according to any one of claims 1 to 3, wherein the rotary shaft is installed in the cylinder in an eccentric state.

Images