JPH1163001A - Shaft coupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such a shaft coupler with a small size in the axial direction as being capable of easily pushing a load shaft into an output shaft without coming-off even if a set screw loosens. SOLUTION: The hollow portion 15 of a load shaft 14 is pushed into the output shaft 12 of a motor 1 to fasten and lock a set screw 16. During push-in, air in the hollow portion 15 escapes from a D-cut portion 13, resulting in easy push-in. The depth U of the D-cut portion 13 is larger than a gap S between a gear shaft 14 and a bracket to prevent the set screw 16 from being unlocked at its end from the motor shaft 12 with the head of the set screw 16, if loosened, stuck at the bracket 18. An oil seal 17 is disposed in a space on the outer periphery of' the gear shaft 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft coupling device for transmitting rotation of a rotary power source such as an electric motor to a load.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing a conventional shaft coupling device. In the drawing, reference numeral 1 denotes a motor, 2 denotes a motor shaft as an output shaft, and a part of the outer periphery thereof is cut in parallel with the shaft. Thus, a D cut portion 3 is formed. Reference numeral 4 denotes a gear shaft serving as a load shaft, and a hollow portion 5 of the gear shaft 4 fits with the motor shaft 2. 6
Is a set screw which is inserted into a screw hole formed in the gear shaft 4 and abuts on the surface of the D-cut portion 3. The screw is tightened to prevent rotation of the shaft. Reference numeral 7 denotes an oil seal provided on the outer periphery of the motor shaft 2, which is disposed closer to the motor 1 than a portion where the motor shaft 2 and the gear shaft 4 overlap. Reference numeral 8 denotes a bracket that covers the outer circumference of the motor shaft 2 to the gear shaft 4 and is fixed to the motor 1 by fixing bolts 9. Here, the set screw 6 is not covered by the bracket 8, and the surface is exposed. The length Ld of the D-cut portion 3 is smaller than the pushing dimension Ls of the gear shaft 4.

[0003]

Since the conventional shaft coupling device is constructed as described above, if the set screw is loosened due to vibration of the shaft, the set screw rises and does not function as a detent, and further falls off. There was a fear that it would. Also, when the load shaft is pushed into the output shaft, the clearance in the hollow portion of the load shaft for allowing air to escape to the outside is small, and it is difficult to push the load shaft. In addition, since the oil seal and the load shaft are arranged in the axial direction on the outer periphery of the output shaft, there is a problem that the axial dimension becomes long.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a simple structure that retains the function of preventing the set screw from rotating, prevents the screw from falling off, and pushes the load shaft into the output shaft. It is another object of the present invention to obtain a shaft coupling device that is easy to use and has a small axial dimension.

[0005]

According to a first aspect of the present invention, there is provided a shaft coupling device comprising a bracket for covering a portion where a set screw is disposed, wherein a depth dimension of a cut surface for the set screw is set between the set screw and the inner peripheral surface of the bracket. Is larger than the gap size. According to a second aspect of the present invention, the axial length of the set surface for the set screw is made larger than the pushing dimension of the load shaft.

According to a third aspect of the present invention, an oil seal is provided between the bracket and the outer peripheral surface of the load shaft. According to a fourth aspect of the present invention, the output shaft is a stepped shaft having a small diameter at the front end side, and the output shaft is formed with a shaved surface for a set screw reaching the large diameter portion from the front end.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a cross-sectional view of a shaft coupling device according to a first embodiment of the present invention. A case where the rotation of an electric motor is reduced by a gear and transmitted to a load will be described. In the figure, 1 is a motor as a rotary power source, 12 is a cylindrical motor shaft as its output shaft, 13 is a D-cut portion, which is formed by shaving a part of the outer periphery of the motor shaft 12 in parallel with the shaft. And
That surface constitutes the set screw cutting surface. FIG. 2 shows a cross section of the motor shaft 12. U is a depth dimension of the D cut portion 13 from the outer peripheral surface of the motor shaft 12. Reference numeral 14 denotes a gear shaft serving as a load shaft, and a hollow portion 15 formed at a left portion in the figure.
Fits with the motor shaft 12 and is combined with a large-diameter gear (not shown) at the right portion so that the rotation of the motor 1 is reduced and transmitted to the load. The axial length Ld of the D-cut portion 13 is set to be larger than the pushing dimension of the gear shaft 14 (the overlapping dimension of the motor shaft 12 and the gear shaft 14) Ls. FIG. 3 is an enlarged view of an inlet portion 22 of the gear shaft 13, that is, a portion opened at the left end in FIG.
The angle α is smaller than that of a general chamfer as shown in FIG. 7A, or the radius R is rounded as shown in FIG.

Reference numeral 21 denotes a screw hole formed in the gear shaft 14;
Reference numeral 6 denotes a set screw which is inserted into the screw hole 21 and abuts on the surface of the D-cut portion 13. By tightening the set screw, the gear shaft 14 is fixed to the motor shaft 12 to prevent rotation. 1
Reference numeral 8 denotes a bracket fixed to the electric motor 1 with fixing bolts 9. The bracket 8 covers the outer periphery of the motor shaft 12 to the gear shaft 14, including the arrangement of the set screw 16.

Assuming that the thickness of the gear shaft is t, the gap between the outer peripheral surface of the gear shaft 14 and the inner peripheral surface of the bracket 18 is S, and the height of the set screw is H,
The gap size between the inner peripheral surface 8 and the inner peripheral surface is S + t + U−H, and the depth size of the D cut portion 13 is set to be larger than this gap size. That is, S + t + U−H <U (1) Therefore, the configuration is such that S + t <H (2) (2) is satisfied.

Reference numeral 17 denotes an oil seal provided between the outer peripheral surface of the gear shaft 14 and the bracket 18. Gear shaft 1
The indentation depth Ls of 4 cannot be too short in order to obtain a stable and secure axial connection. Therefore, the set screw 16
Is provided, there is a space for disposing other members in the remaining portion. In FIG. 1, an oil seal 17 is provided in the space. On the other hand, in FIG. 6, since the oil seal 7 and the set screw 6 are arranged in the axial direction without using the above space, the dimension is large in the axial direction.

FIG. 4 shows a shaft coupling device to be compared with that of FIG. In FIG. 4, since the oil seal 17 is disposed on the load side with respect to the set screw 16, the gear shaft 1
The oil seal 17 approaches the raised portion 23 of FIG. 4 and the lip 24 of the oil seal 17 may be damaged by the raised portion 23. To prevent this, the parallel portion 25 of the gear shaft 14 is used.
Can be lengthened, but the cost increases. If the oil seal 17 is arranged closer to the electric motor 1 than the set screw 16 as shown in FIG.
6 is not adversely affected, and the arrangement of FIG. 1 is more preferable.

Next, the operation will be described. First, FIG.
When the gear shaft 14 is pushed into the motor shaft 12, the air in the hollow portion 15 of the gear shaft 14 escapes through the D-cut portion 13 as shown by the arrow A, so that the pushing becomes easy. Furthermore, since the chamfering angle α of the inlet portion 22 of the gear shaft 14 is reduced or rounded, it is easy to push. Also, even when the set screw 16 is loosened due to vibration during operation, the bracket 18 can be set to the set screw 1.
6, the head of the setscrew 16 is held and does not fall off. Further, since the dimensional relationship satisfies the expression (2), even when the set screw 16 is loosened and floats, the tip does not come off from the motor shaft 12 and functions as a detent and functions as a detent. Of the gear shaft 14
To be sure.

Embodiment 2 FIG. FIG. 5 is a cross-sectional view of a shaft coupling device according to a second embodiment of the present invention, in which the motor shaft 12 is a stepped shaft having a small diameter at the distal end. In the figure, 28
Is a step formed with the motor shaft 12, 29 is a small-diameter portion on the tip side of the step 28, that is, on the load side, and 30 is a large-diameter portion on the motor 1 side of the step 28. The tip of the motor shaft 12 and the gear shaft 14
A gap is provided between the bottom of the hollow portion 15 and the tip of the gear shaft 14 is in contact with the step portion 28. The D-cut portion 13 is formed to have a length extending from the tip of the motor shaft 12 to the large-diameter portion 30. With this configuration, even when a stepped shaft is used for the motor shaft 12, the gear shaft 14
Can be easily pushed.

In the first and second embodiments,
Although the surface of the D cut portion 13 is shown as a set screw shaving surface, for example, the set screw 16 may be brought into contact with the bottom surface of the key groove-shaped concave portion, and the gear shaft 14 is shown as a load shaft. It can also be applied when no gear is used. Further, although the electric motor 1 is shown as a rotary power source, it can be applied to an internal combustion engine or the like.

[0015]

According to the shaft coupling device of the first aspect, the depth of the shaved surface for the set screw is made larger than the gap between the set screw and the inner peripheral surface of the bracket, so that the set screw is loosened. Even in this case, it functions as a detent without deviating from the output shaft, and further prevents falling off. According to the shaft coupling device of the second aspect, since the length of the shaved surface for the set screw in the axial direction is larger than the pushed-in size of the load shaft, an escape path for air in the hollow portion is formed, and the load on the output shaft is reduced. Pushing of the shaft becomes easy.

According to the shaft coupling device of the third aspect, since the oil seal is provided between the bracket and the outer peripheral surface of the load shaft, the space on the outer peripheral surface of the load shaft can be used, and the axial dimension can be increased. Becomes smaller. According to the shaft coupling device of the fourth aspect, since the cut surface for the set screw reaching the large-diameter portion from the tip of the stepped output shaft is formed, it is easy to push the load shaft.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a shaft coupling device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the motor shaft according to Embodiment 1 of the present invention.

FIG. 3 is a sectional view of an inlet portion of the gear shaft according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a shaft coupling device as a comparison object with the shaft coupling device of FIG. 1;

FIG. 5 is a sectional view of a shaft coupling device according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a conventional shaft coupling device.

[Explanation of symbols]

1 motor, 12 motor shaft, 13 D cut part, 14
Gear shaft, 15 hollow part, 16 set screw, 17 oil seal, 18 bracket, 21 screw hole, 28 stepped part, 29 small diameter part, 30 large diameter part.

Claims (4)

[Claims] 1. A shaft coupling device comprising: a cylindrical output shaft of a rotary power source; and a load shaft having a bottomed hollow portion that fits into the output shaft, wherein a screw formed in a radial direction of the load shaft is provided. The set screw which is inserted into the hole and which comes into contact with a set screw shaving surface formed in a shape obtained by shaving a part of the outer periphery of the output shaft in parallel with the shaft, and the load including the set portion of the set screw A bracket that covers the outer periphery of the shaft and is fixed to the rotary power source, and the depth dimension of the set screw shaving surface from the outer peripheral surface of the output shaft is the inner peripheral surface of the set screw and the bracket. A shaft coupling device having a clearance larger than a gap size of the shaft coupling. 2. The axial length dimension of the set screw shaving surface is:
2. The shaft coupling device according to claim 1, wherein the dimension is larger than a pushing dimension of the load shaft. 3. The shaft coupling device according to claim 1, wherein an oil seal is provided between the bracket and the outer peripheral surface of the load shaft. 4. The output shaft is a stepped shaft having a small diameter at the distal end, and a gap is provided between the distal end of the output shaft and the bottom of the hollow portion of the load shaft, and the distal end of the load shaft is connected to the output shaft. 3. The shaft coupling device according to claim 1, wherein a shaved surface for a set screw is formed on the output shaft so as to contact the stepped portion and reach the large diameter portion from the tip of the output shaft.