JP6938099B2 - Shaft joint - Google Patents

Description

The present invention relates to a shaft joint that connects shafts.

A shaft joint (coupling) is a component that connects shafts, and is used for the purpose of transmitting power from one shaft to the other shaft and extending the length of the shaft. For example, by rotating the drive shaft by the drive unit in a state where the shaft (drive shaft) of the drive unit and the driven unit are fixed to the shaft joint, the power of rotation can be transmitted to the driven unit.

Various methods for fixing the shaft to the shaft joint have been proposed. For example, Patent Document 1 discloses a shaft joint composed of a joint member having a shaft hole into which a shaft is inserted and a slit provided so as to reach the shaft hole from an outer peripheral surface. There is. In this type of shaft joint, with the shaft inserted into the shaft hole, it is formed on the other side of the joint member through a tightening bolt mounting hole formed on one side of the joint member separated by a slit. Screw the fastening bolt into the thread groove. As a result, the distance between the slits is narrowed, and the shaft and the shaft joint are fixed.

Further, Patent Document 2 discloses a shaft joint using a set screw for fixing the shaft. In this type of shaft joint, a screw hole that reaches the shaft hole is formed in a direction perpendicular to the shaft inserted into the shaft hole. With the shaft inserted in the shaft hole, the set screw is screwed into the screw hole and the tip of the set screw is brought into contact with the outer peripheral surface of the shaft to fix the shaft and the shaft joint.

Japanese Unexamined Patent Publication No. 2007-232137 Japanese Unexamined Patent Publication No. 2014-52016

In the shaft joint using the above-mentioned tightening bolt, the head of the tightening bolt is immersed in the tightening bolt mounting hole, and the shaft is fixed by tightening the tightening bolt. Since this tightening bolt is provided so that the thickness direction of the joint member and the radial direction of the tightening bolt coincide with each other, the thickness of the joint member cannot be made thinner than the diameter of the head of the fastening bolt. , There was a limit to the miniaturization of shaft joints.

On the other hand, in the shaft joint using the above-mentioned set screw, since the set screw without a head is used for fixing the shaft, the thickness of the shaft joint can be suppressed and the size can be reduced. However, in such a shaft joint, since the tip of the set screw contacts only a part of the outer peripheral surface of the shaft to fix the shaft, the entire outer peripheral surface of the shaft cannot be fixed, and the fixing strength is weak. There was a problem.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a small shaft joint capable of firmly fixing a shaft.

According to the present invention, between a main body portion which is a shaft joint for connecting shafts and has an opening extending from the front surface side to the back surface side and an inner peripheral surface of the main body portion exposed by the opening in the opening. The main body includes a cantilever-shaped flexible structure portion provided in the above so as to form a gap corresponding to a shaft hole into which the shaft can be inserted, and an end portion connected to the main body portion. Is provided with a screw hole that reaches a region of the inner peripheral surface opposite to the gap from the outer peripheral surface of the main body portion, and the flexible structure portion extends from the gap. And a second slit and a third slit extending from the end of the second slit toward the end of the first slit and not connected to the first slit. The first slit and the second slit are formed so as to be formed between the inner peripheral surface and the inner peripheral surface, and the set screw is screwed into the screw hole to insert the set screw. By contacting the flexible structure portion and bending the flexible structure portion in the direction of the gap, the inner peripheral surface and the flexible structure portion fix the shaft inserted in the gap. Shaft joints are provided.

Further, in the present invention, a convex portion extending the gap may be provided in the region surrounding the gap between the main body portion and the flexible structure portion.

Since the shaft joint according to the present invention uses a set screw without a head for fixing the shaft inserted into the shaft hole, the thickness of the shaft joint can be suppressed and the size can be reduced. Further, in the shaft joint according to the present invention, the diameter of the shaft hole is reduced by bringing the set screw into contact with the flexible structure portion to bend the flexible structure portion, and the shaft inserted into the shaft hole. Fix the entire outer peripheral surface. As a result, the shaft can be firmly fixed as compared with the case where the set screw is brought into contact with only a part of the outer peripheral surface of the shaft to fix the shaft.

It is a perspective view which shows the surface side of a shaft joint. It is a perspective view which shows the back surface side of a shaft joint. It is sectional drawing of a shaft joint. 4 (A) and 4 (B) are enlarged cross-sectional views of the flexible structure portion.

Embodiments of the present invention will be described with reference to the accompanying drawings. A configuration example of the shaft joint according to the present embodiment is shown in FIGS. 1 to 3. FIG. 1 is a perspective view showing the front surface side of the shaft joint 11 for connecting the shafts, FIG. 2 is a perspective view showing the back surface side of the shaft joint 11, and FIG. 3 is a cross-sectional view of the shaft joint 11. ..

The shaft joint 11 includes a cylindrical main body portion 13 having a front surface 13a (FIG. 1), a back surface 13b (FIG. 2), and an outer peripheral surface 13c forming an outer edge. An opening 13d extending from the front surface 13a side to the back surface 13b side of the main body portion 13 is provided in the region near the center of the main body portion 13, and the main body portion 13 includes an inner peripheral surface 13e exposed by the opening 13d.

The opening 13d is formed into a semi-cylindrical shape obtained by dividing an arbitrary cylinder into two in the height direction, and the inner peripheral surface 13e of the main body 13 has a curved first region 13f and a planar second region 13f. It is composed of a region of 13 g. However, the shape of the opening 13d is not limited to the above, and can be changed as appropriate.

A flexible structure portion 15 is provided in the opening 13d of the main body portion 13 from the front surface 13a side to the back surface 13b side of the main body portion 13. The flexible structure portion 15 is formed in a semi-cylindrical shape corresponding to the shape of the opening 13d, and has a curved first region 15a located along the first region 13f of the inner peripheral surface 13e and an inner peripheral surface. It is composed of a planar second region 15b located along the second region 13g of 13e.

Further, the flexible structure portion 15 is provided with a connecting portion 15c at one end corresponding to a boundary portion between the first region 15a and the second region 15b. The first region 15a and the second region 15b are separated by the connecting portion 15c. The connecting portion 15c is connected in the vicinity of the boundary between the first region 13f and the second region 13g of the main body portion 13. Therefore, the flexible structure portion 15 is formed in a cantilever shape with the connecting portion 15c as a fixed end.

Further, the flexible structure portion 15 is provided so that a gap into which a shaft can be inserted is formed between the flexible structure portion 15 and the second region 13g of the inner peripheral surface 13e. The gap corresponds to a shaft hole 17 into which a shaft or the like of a drive unit (not shown) fixed to the shaft joint 11 is inserted. The shaft hole 17 is configured to reach from the front surface 13a side to the back surface 13b side and penetrate the shaft joint 11.

Further, the flexible structure portion 15 is provided so as to form a slit 19 between the inner peripheral surface 13e and the flexible structure portion 15 so as to surround the flexible structure portion 15 and reach from the front surface 13a side to the back surface 13b side. For example, the slit 19 is adjacent to the first planar slit 19a and the second slit 19b adjacent to the second region 15b of the flexible structure portion 15 and the first region 15a of the flexible structure portion 15. It is composed of a curved third slit 19c.

As shown in FIG. 3, the first slit 19a and the second slit 19b extend from the shaft hole 17 toward the radial outer side of the main body portion 13, and are shafts when viewed from the front surface 13a side or the back surface 13b side. It is formed in a straight line so as to be symmetrical with respect to the hole 17. Further, the third slit 19c extends from the end of the second slit 19b toward the end of the first slit 19a in a semicircular shape when viewed from the front surface 13a side or the back surface 13b side, and the first slit 19c is formed. It is configured so as not to be connected to the slit 19a of. A connecting portion 15c is provided between the end portion of the first slit 19a and the end portion of the third slit 19c.

When an external force acts on the first region 15a located on the side opposite to the shaft hole 17 of the flexible structure portion 15, the vicinity of the fixed end of the flexible structure portion 15 (near the connecting portion 15c) is elastically deformed. Then, the free end side of the flexible structure portion 15 is displaced toward the shaft hole 17 side. As a result, the diameter of the shaft hole 17 is reduced and the shaft is fixed.

The shapes of the flexible structure portion 15 and the slit 19 are not limited to those exemplified above. The shape of the flexible structure portion 15 is not particularly limited as long as it has a cantilever shape having a connecting portion 15c, and the shape of the slit 19 can be appropriately changed as long as the flexible structure portion 15 can be deformed. ..

Further, the main body 13 is provided with a screw hole 13h that reaches a first region 13f located on the side opposite to the shaft hole 17 of the inner peripheral surface 13e from the outer peripheral surface 13c, and is fixed in the screw hole 13h. The screw 21 is inserted. As shown in FIG. 3, the screw hole 13h is provided so as to reach the first region 13f of the inner peripheral surface 13e that faces the second region 13g in contact with the shaft hole 17, and the screw hole 13h is formed with the slit 19. It is connected.

When the set screw 21 is inserted into the screw hole 13h from the outer peripheral surface 13c and the set screw 21 is rotated in the screwing direction, the set screw 21 is screwed from the outer peripheral surface 13c toward the first region 13f of the inner peripheral surface 13e. Finally, it comes into contact with the flexible structure portion 15.

As shown in FIG. 1, it is preferable to provide a convex portion 23 that projects toward the surface 13a and extends the shaft hole 17 in the region surrounding the shaft hole 17 of the main body portion 13 and the flexible structure portion 15. By providing the convex portion 23, the contact area between the shaft joint 11 and the shaft inserted into the shaft hole 17 can be increased, and the fixing strength of the shaft can be improved.

Next, the details of the mechanism for fixing the shaft inserted in the shaft hole 17 will be described. FIG. 4A is an enlarged cross-sectional view of the flexible structure portion 15 shown in FIG. A shaft 25 of a driving portion or a driven portion (not shown) is inserted into the shaft hole 17, and a set screw 21 is inserted into the screw hole 13h. When the set screw 21 inserted into the screw hole 13h is rotated in the screwing direction, the tip 21a of the set screw 21 comes into contact with the flexible structure portion 15.

When the tip 21a of the set screw 21 is in contact with the flexible structure portion 15 and then the set screw 21 is further rotated and screwed in, the flexible structure portion 15 is pushed by the set screw 21 and mainly has a flexible structure. Elastic deformation occurs in the vicinity of the fixed end of the portion 15 (near the connecting portion 15c), and the free end side of the flexible structure portion 15 bends toward the shaft hole 17 side. FIG. 4B is an enlarged cross-sectional view of the flexible structure portion 15 in a state where it is pushed by the set screw 21 and is bent.

When the flexible structure portion 15 bends toward the shaft hole 17, the diameter of the shaft hole 17 is reduced, and the shaft is formed by the second region 13g of the inner peripheral surface 13e and the second region 15b of the flexible structure portion 15. The shaft 25 inserted into the hole 17 is fixed. In this way, the shaft 25 can be fixed to the shaft joint 11.

When the shaft 25 inserted into the shaft hole 17 is separated from the shaft joint 11, the set screw 21 is rotated in a loosening direction and moved away from the flexible structure portion 15. As a result, the elastic deformation of the flexible structure portion 15 is eliminated, the diameter of the shaft hole 17 is expanded, and the shaft 25 inserted into the shaft hole 17 can be separated.

Since the shaft joint 11 described in the present embodiment uses the set screw 21 for fixing the shaft inserted into the shaft hole 17, the thickness of the shaft joint 11 can be suppressed and the size can be reduced. Further, in the shaft joint 11 described in the present embodiment, the diameter of the shaft hole 17 is reduced by bringing the set screw 21 into contact with the flexible structure portion 15 and bending the flexible structure portion 15 to reduce the diameter of the shaft. The entire outer peripheral surface of the shaft inserted into the hole 17 is fixed. As a result, the shaft can be firmly fixed as compared with the case where the set screw 21 is brought into contact with only a part of the outer peripheral surface of the shaft to fix the shaft.

When fixing the shaft to the shaft joint 11, for example, a drive unit (not shown) is provided on the front surface 13a side of the main body 13 shown in FIG. 1, and a driven unit (not shown) is provided on the back surface 13b side shown in FIG. ) Is provided. Then, the shaft of the drive unit is inserted and fixed in the shaft hole 17, and the driven portion on the back surface 13b side of the main body portion 13 is fixed. As a result, the power of the shaft of the drive unit can be transmitted to the driven unit.

There is no limitation on the method of fixing the driven portion of the main body portion 13. For example, a plurality of screw holes 13i (see FIGS. 1 and 2) provided in the main body 13 and extending from the front surface 13a side to the back surface 13b side are inserted to fix the driven portion, and the main body 13 is driven. The part may be fixed. Specifically, for fixing the driven portion in a state where the driven portion provided with the screw hole is in contact with the main body portion 13 so that the screw holes and the screw holes 13i of the main body portion 13 are aligned with each other. A screw is screwed into the screw hole of the driven portion from the surface 13a side of the main body portion 13 via the screw hole 13i. As a result, the driven portion can be fixed to the main body portion 13.

For example, a motor can be used as the drive unit. In this case, the shaft of the motor is inserted and fixed in the shaft hole 17. Then, when the motor is driven to rotate the shaft, the power of rotation is transmitted to the driven portion.

Although the example in which the shaft of the driving portion is fixed to the shaft hole 17 has been described here, the shaft of the driven portion may be fixed to the shaft hole 17. For example, an encoder for detecting the angle of rotation can be provided as a driven portion on the surface 13a side of the main body portion 13, and the shaft of the encoder can be inserted and fixed in the shaft hole 17. In this case, the rotation angle of the drive unit fixed to the back surface 13b side of the main body unit 13 can be detected by the encoder.

In addition, the structure, method, etc. according to the above-described embodiment can be appropriately modified and implemented as long as they do not deviate from the scope of the object of the present invention.

11 Shaft joint 13 Main body 13a Surface
13b Back surface 13c Outer surface surface 13d Opening 13e Inner peripheral surface 13f First area 13g Second area 13h Screw hole 13i Screw hole 15 Flexible structure part 15a First area 15b Second area 15c Connecting part 17 Shaft hole 19 Slit 19a 1st slit 19b 2nd slit 19c 3rd slit 21 Set screw 21a Tip 23 Convex 25 Axis

Claims (2)

A shaft joint that connects shafts
A main body with an opening that extends from the front side to the back side,
A gap corresponding to a shaft hole into which the shaft can be inserted is formed in the opening with the inner peripheral surface of the main body exposed by the opening, and the end portion is connected to the main body. Includes a cantilever-like flexible structure
The main body is provided with a screw hole that reaches a region located on the inner peripheral surface opposite to the gap from the outer peripheral surface of the main body.
The flexible structure extends from the first slit and the second slit extending from the gap and from the end of the second slit toward the end of the first slit. A third slit, which is not connected to the first slit, is provided so as to be formed between the inner peripheral surface and the third slit .
The first slit and the second slit are formed so as to sandwich the gap.
The inner peripheral surface and the flexible structure are formed by screwing a set screw into the screw hole, bringing the set screw into contact with the flexible structure portion, and bending the flexible structure portion in the direction of the gap. shaft coupling you, characterized in that to fix the shaft inserted into the gap between the parts. The shaft joint according to claim 1, wherein a convex portion extending the gap is provided in a region surrounding the gap between the main body portion and the flexible structure portion.

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