JP4080032B2 - Shaft coupling device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shaft coupling device that transmits rotation of a rotational power source such as an electric motor to a load.
[0002]
[Prior art]
FIG. 6 is a cross-sectional view showing a conventional shaft coupling device, in which 1 is an electric motor, 2 is an electric motor shaft that is an output shaft thereof, and a part of the outer periphery thereof is shaved parallel to the shaft to form a D-cut portion 3. Is formed. A gear shaft 4 is a load shaft, and a hollow portion 5 of the gear shaft is fitted to the motor shaft 2. Reference numeral 6 denotes a set screw which is inserted into a screw hole formed in the gear shaft 4 and is in contact with the surface of the D-cut portion 3 and tightens this to prevent the shaft from rotating. An oil seal 7 is provided on the outer periphery of the electric motor shaft 2 and is disposed closer to the electric motor 1 than a portion where the electric motor shaft 2 and the gear shaft 4 overlap each other. A bracket 8 covers the outer periphery of the motor shaft 2 to the gear shaft 4 and is fixed to the motor 1 with fixing bolts 9. Here, the set screw 6 is not covered with the bracket 8, and the surface is exposed. Note that the length dimension Ld of the D-cut portion 3 is smaller than the pushing dimension Ls of the gear shaft 4.
[0003]
[Problems to be solved by the invention]
Since the conventional shaft coupling device is configured as described above, if the set screw is loosened due to the vibration of the shaft, the set screw is lifted to stop functioning as a detent and may fall off.
Further, when the load shaft is pushed into the output shaft, there is only a small clearance for the air in the hollow portion of the load shaft to escape to the outside.
Further, 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.
[0004]
The present invention has been made to solve the above-described problems, and has a simple structure that keeps the set screw non-rotating function and prevents it from falling off. In addition, the load shaft can be easily pushed into the output shaft. It is another object of the present invention to obtain a shaft coupling device having a small axial dimension.
[0005]
[Means for Solving the Problems]
Shaft coupling device according to claim 1, a cylindrical output shaft of the rotary power source, and a load shaft having a hollow portion with a bottom mate with the output shaft, the output shaft, the hollow portion of the load shaft In the part of the outer periphery of the part where the two parts fit together, a shaving surface parallel to the axis is formed, and in the state where the hollow part of the load shaft is fitted to the output shaft, the screw hole provided in the radial direction of the hollow part of the load shaft The output shaft and the load shaft are fixed by screwing the set screw into contact with the shaving surface of the output shaft. The output shaft and the load shaft are covered and the outer periphery of the load shaft is covered and fixed to the rotational power source. In the state where the output shaft and the load shaft are fixed, the set screw is formed between the set screw and the inner peripheral surface of the bracket rather than the depth of the shaving surface of the output shaft. The height is such that the gap becomes small.
In the shaft coupling device according to the second aspect, the axial length dimension of the set surface for the set screw is made larger than the indentation dimension on the load side.
[0006]
In the shaft coupling device according to the third aspect, an oil seal is provided between the outer peripheral surface of the load shaft and the bracket.
In the shaft coupling device according to claim 4, the output shaft is a stepped shaft having a small diameter on the tip side, and a gap is provided between the tip of the output shaft and the bottom surface of the hollow portion of the load shaft and the tip of the load shaft is output. A shaving surface is formed so as to contact the stepped portion of the shaft and to contact the tip of the set screw while the output shaft reaches the large diameter portion from the tip .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of a shaft coupling device showing Embodiment 1 of the present invention, and a case where the rotation of an electric motor is decelerated by a gear and transmitted to a load will be described. In the figure, 1 is an electric motor that is a rotational power source, 12 is a cylindrical motor shaft that is its output shaft, 13 is a D-cut portion, and a part of the outer periphery of the motor shaft 12 is cut in parallel to the shaft. The surface constitutes a set screw shaving surface. FIG. 2 shows a cross section of the motor shaft 12. U is the depth dimension of the D-cut portion 13 from the outer peripheral surface of the motor shaft 12. 14 is a gear shaft that is a load shaft. A hollow portion 15 formed in the left portion in the drawing is fitted with the motor shaft 12 and is combined with a large-diameter gear (not shown) in the right portion to reduce the rotation of the motor 1. And tell the load. The length Ld in the axial direction of the D-cut portion 13 is 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 the inlet portion 22 of the gear shaft 13, that is, the portion opened at the left end in FIG. 1, and the angle α is made smaller than the general chamfer as shown in FIG. As shown, the radius R is rounded.
[0008]
21 is a screw hole formed in the gear shaft 14, 16 is a set screw inserted into the screw hole 21 and abutting against the surface of the D-cut portion 13, and is fastened to fix the gear shaft 14 to the motor shaft 12. I have a rotation stop. Reference numeral 18 denotes a bracket fixed to the electric motor 1 with a fixing bolt 9 and covers the outer periphery of the bracket from the electric motor shaft 12 to the gear shaft 14 including the arrangement portion of the set screw 16.
[0009]
Now, assuming that the thickness of the gear shaft is t, the clearance dimension 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 set screw is screwed into the output shaft and the load. in a state in which the shaft is fixed, the gap dimension δ of the inner peripheral surface of the set screw 16 and the bracket 18 Ri Do and S + t + U-H, gap size δ is the depth dimension U of the D-cut portion, smaller so Set the height H of the set screw . Ie
S + t + U−H <U (1)
Therefore
S + t <H (2)
By setting the height H of the set screw so as to satisfy the expression (2) , the condition [gap dimension δ <D cut part depth dimension U] is satisfied.
[0010]
An oil seal 17 is provided between the outer peripheral surface of the gear shaft 14 and the bracket 18. The indentation depth Ls of the gear shaft 14 cannot be made too short in order to obtain a stable and reliable shaft coupling. Therefore, even if the set screw 16 is provided, there is a space for arranging 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 space, the dimension is large in the axial direction.
[0011]
FIG. 4 shows a shaft coupling device as an object to be compared with that of FIG. In FIG. 4, since the oil seal 17 is disposed on the load side of the set screw 16, the oil seal 17 may approach the rounded portion 23 of the gear shaft 14, and the lip 24 of the oil seal 17 may be damaged at the rounded portion 23. . To prevent this, the parallel part 25 of the gear shaft 14 may 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. 1, even if the round-up portion 23 is large, the set screw 16 and the like are not adversely affected, and the arrangement shown in FIG.
[0012]
Next, the operation will be described. First, when the gear shaft 14 is pushed into the motor shaft 12 in FIG. 1, the air in the hollow portion 15 of the gear shaft 14 escapes to the outside through the D-cut portion 13 as indicated by the arrow A, so that pushing is easy. Become. Furthermore, since the chamfering angle α of the inlet portion 22 of the gear shaft 14 is reduced or rounded, the pushing becomes easy.
Even when the set screw 16 is loosened due to vibration during operation or the like, the bracket 18 is covered with the set screw 16 so that the head of the set screw 16 is grasped and does not fall off. Further, since the dimensional relationship satisfies the expression (2), even if 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 the motor shaft 12. Is reliably transmitted to the gear shaft 14.
[0013]
Embodiment 2. FIG.
FIG. 5 is a cross-sectional view of the shaft coupling device showing Embodiment 2 of the present invention, in which the motor shaft 12 is a stepped shaft having a small diameter on the tip side. In the figure, 28 is a step portion formed with the motor shaft 12, 29 is a small-diameter portion on the tip side, that is, the load side from the step portion 28, and 30 is a large-diameter portion on the motor 1 side from the step portion 28. A space is provided between the tip of the electric motor shaft 12 and the bottom surface of the hollow portion 15 of the gear shaft 14, and the tip of the gear shaft 14 is brought into contact with the stepped portion 28. The D-cut portion 13 is formed to have a length that reaches the large-diameter portion 30 from the tip of the electric motor shaft 12.
With this configuration, even when a stepped shaft is used as the motor shaft 12, the gear shaft 14 can be easily pushed.
[0014]
In the first and second embodiments, the surface of the D-cut portion 13 is shown as the set screw cutting surface. However, for example, the set screw 16 may be brought into contact with the bottom surface of the key groove-shaped recess. Although the gear shaft 14 is shown as the load shaft, the present invention can also be applied when no gear is used. Furthermore, although the electric motor 1 is shown as a rotational power source, the present invention can also be applied to an internal combustion engine or the like.
[0015]
【The invention's effect】
According to the shaft coupling device of the first aspect, in the fixed state of the output shaft and the load shaft, the height of the set screw is between the inner peripheral surface of the set screw bracket and the depth of the shaving surface of the output shaft. Since the gap to be formed is set to be small, even when the set screw is loosened, 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 axial length dimension of the set surface for the set screw is made larger than the pushing dimension of the load shaft, air can escape from the hollow portion, and the load on the output shaft can be reduced. Pushing the shaft becomes easy.
[0016]
According to the shaft coupling device of the third aspect, since the oil seal is provided between the outer peripheral surface of the load shaft and the bracket, the space on the outer peripheral surface of the load shaft can be used, and the axial dimension is reduced. .
According to the shaft coupling device of the fourth aspect, since the set screw shaving surface that reaches the large diameter portion from the tip of the stepped output shaft is formed, the load shaft can be easily pushed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a shaft coupling device showing Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view of an electric motor shaft according to Embodiment 1 of the present invention.
FIG. 3 is a cross-sectional view of an inlet portion of a gear shaft according to Embodiment 1 of the present invention.
4 is a cross-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 showing Embodiment 2 of the present invention.
FIG. 6 is a cross-sectional view of a conventional shaft coupling device.
[Explanation of symbols]
1 electric motor, 12 electric motor shaft, 13 D cut part, 14 gear shaft,
15 hollow part, 16 set screw, 17 oil seal, 18 bracket,
21 screw holes, 28 steps, 29 small diameter, 30 large diameter.

Claims (4)

A cylindrical output shaft of a rotational power source and a load shaft having a bottomed hollow portion that fits into the output shaft, and the output shaft is a part of an outer periphery of a portion in which the hollow portion of the load shaft fits A cutting surface parallel to the axis is formed, and with the hollow portion of the load shaft inserted into the output shaft, a set screw is screwed into a screw hole provided in the radial direction of the hollow portion of the load shaft. in the axial coupling device for fixing the output shaft and the load shaft by abutting the scraping surface of the output shaft Te, the source of rotational power with covering the outer periphery of the load shaft, including an arrangement portion of the set screw In the state where the output shaft and the load shaft are fixed, the set screw has an inner peripheral surface of the set screw and the bracket that is deeper than the depth of the shaving surface of the output shaft. The height of the gap formed between Shaft coupling device according to claim.   2. The shaft coupling device according to claim 1, wherein the axial length of the set screw shaving surface is larger than the pushing dimension of the load shaft.   The shaft coupling device according to claim 1 or 2, wherein an oil seal is provided between the outer peripheral surface of the load shaft and the bracket.   The output shaft is a stepped shaft with a small diameter on the tip side, and a space is provided between the tip of the output shaft and the bottom surface of the hollow portion of the load shaft, and the tip of the load shaft is in contact with the step of the output shaft 3. The shaft coupling device according to claim 1, wherein a shaving surface is formed on the output shaft so as to abut the tip of the set screw while reaching the large diameter portion from the tip of the output shaft.

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