JPS6364653B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an elastic shaft joint that allows relatively large bending and displacement of the shaft center. The structure of a conventional elastic shaft joint is shown in FIGS. 1 to 6. Figure 1 shows a longitudinal cross-sectional view of an elastic shaft joint.
FIG. 2 is a front view of FIG. 1 and shows the arrangement of the elastic blocks. In the figure, elastic blocks 5 made of a rubber body 3 and an adhesive plate 4 are arranged on both left and right sides of a flange 2 provided at the end of an output shaft 1. On the other hand, the elastic block 5 is sandwiched and held between a disk 7 provided at the end of the input shaft 6 and a disk 9 connected to the disk 7 by a bolt 8. There is. Reference numeral 10 denotes a protrusion that is integrated with the adhesive plate 4, and is fitted into holes provided in the flange 2 and the discs 7 and 9 to position the elastic block 5 and transmit torque. FIG. 3 is a longitudinal sectional view similar to FIG. 1, showing a state in which the input shaft is bent at an angle α around point O. In the figure, A, B, C,
If D represents an elastic block, A and D of the elastic block 5 are subjected to a compression force as well as a shear force,
B and C are subjected to tensile force as well as shear force. At B and C of the elastic blocks 5 which receive this tensile force, gaps δ ₁ and δ ₂ are created by the tensile force as shown in the figure.
occurs, and if the gaps δ ₁ and δ ₂ become large, there is a risk that B and C of the elastic blocks 5 may fall off. Therefore,
Normally, all elastic blocks 5 are precompressed. However, in elastic blocks 5 A and D, the strain due to precompression is added to the compressive strain due to bending deformation, and when viewed from the limit of allowable strain, the allowable bending angle as an elastic shaft joint is not too high. The drawback was that it could not be made larger. Next, FIG. 4 is a longitudinal sectional view showing another example of a conventional elastic shaft joint, FIG. 5 is a sectional view taken along line E-E in FIG.
The figure is a longitudinal cross-sectional view similar to FIG. 4, and shows a state in which the input shaft is bent at an angle α around point O. In the figure, in this configuration, one end surface of a donut-shaped rubber body 13 is bonded to a flange 12 provided at the end of an input shaft 11, and an adhesive plate 14 is bonded to the other end surface of the rubber body 13. The protrusion 15 provided on the adhesive plate 14 is connected to the flange 16 at the shaft end of the output shaft 17.
It fits into the hole provided in the shaft, and performs positioning and torque transmission between each shaft. Note that the joint surface between the flange 12 and the rubber body 13 is a point P where the joint surface between the adhesive plate 14 and the rubber plate 13 is extended toward the shaft center and intersects with the shaft center.
The shear strain rate of the rubber body 13 due to the torsional torque of the shaft is made constant regardless of the radial position of the rubber body 13.
That is, when a twist is applied to the input shaft 11 such that the twist angle θ is given, from the radial position r ₁ of the rubber body 13
The torsional shear strain at r ₂ increases from r ₁ θ to r ₂ θ, but the thickness of the rubber body 13 also becomes b ₁ = r ₁ tan β, b ₂ =
r ₂ tanβ and the outer periphery are thicker, so the shear strain rate ε ₁ = r ₁ θ/b ₁ = θ/tanβ, ε ₂ = r ₂ θ/b ₂ = θ/
tanβ, which remains constant regardless of the radial position.
In order to obtain such an effect, the flange joint surface is made into a conical surface as described above, but this configuration does not provide any effective effect against bending of the axis. That is, as shown in Figure 6,
When the input shaft 11 is bent at an angle α around point O, if the upper and lower positions of the rubber body 13 in the figure are represented by part F and part G, the rubber body 13
The F section is subjected to tensile force as well as shear force. Therefore, a gap of δ ₃ was created on the mounting surface of the adhesive plate 14, and if this gap δ ₃ became large, there was a risk that the protrusion 15 would come off from the flange 6. In view of the above points, the present invention does not generate a tensile force in the elastic body part when the axis is bent, or by keeping it to a very small amount, it is possible to tolerate a large bending angle, and to prevent the elastic block from falling off. The purpose of this invention is to provide an elastic shaft joint that can eliminate such problems. Next, the present invention will be explained with reference to FIGS. 7 to 12. FIG. 7 is a longitudinal sectional view showing an embodiment of the elastic shaft joint according to the present invention, FIG. 8 is a front view of FIG. 7, and FIG. 9 is a longitudinal sectional view similar to FIG. This shows a state in which a bend is made at an angle α around a point. In the figure, elastic blocks 22 made of a rubber body 20 and an adhesive plate 21 are arranged on both left and right sides of a spherical flange 19 provided at the end of an output shaft 18.
The surfaces in contact with the left and right surfaces of the spherical flange 19 and the adhesive plate 21 are composed of spherical surfaces having radii R ₂ and R ₃ centered on the bending center point O of the axis. The other surface of the elastic block 22 is sandwiched and held by a spherical plate 24 provided at the end of the input shaft 23 and a spherical plate 26 connected to this by a bolt 25. In addition, the spherical plates 24 and 2
Similarly to both surfaces of the spherical flange 19, the joint surface between the elastic block 22 and the spherical flange 19 also lies at the bending center point O of the axis.
It is a spherical surface with radius R ₁ and R ₄ centered at .
27 is a protrusion that is integrated with the adhesive plate 21;
It fits into holes provided in the spherical flange 19 and the spherical plates 24 and 26, and positions the elastic block 22 and transmits torque. Next, a state in which the input shaft 23 is bent by an angle α around point O will be described. In such a situation,
Since all of the joint surfaces of the elastic block 22 are spherical with the bending center point O as the center, the distance between the joint surfaces does not change due to the displacement, and a tensile force is generated in the elastic block 22. Never. Therefore, it is not necessary to apply precompression to the elastic block 22 , and it is sufficient to adopt a configuration that takes only the shear deformation of the elastic body into consideration, so that a larger bending angle can be accommodated compared to the above-mentioned conventional example. I can do it. FIG. 10 is a longitudinal sectional view showing a second embodiment of the elastic shaft joint according to the present invention, in which the input shaft is bent at an angle α around point O.
In the figure, this configuration includes a spherical flange 19 and a spherical plate 24 made of the spherical surface of the above-mentioned embodiment.
Reference numeral 26 is a conical flange 29 and conical plates 34 and 36 each having a conical surface, thereby facilitating the manufacture of each member. That is, the conical flange 29
The surfaces in contact with the adhesive plate 31 of the elastic block 32 and the left and right sides of the elastic block 32 are conical surfaces that touch a spherical surface centered at point O at the center point of the protrusion 37, and the inner surfaces of the conical plates 34 and 36 also correspond to the conical flange 29. Similar O
It is a conical surface that is in contact with a spherical surface centered at a point.
According to such a configuration, both surfaces of the elastic block 32 are constituted by conical surfaces in contact with a spherical surface centered at point O, and the amount of change in the interval between the joint surfaces when bending occurs is small, and the rubber body 30 is The generated tensile force can be reduced. Therefore, by applying only a slight precompression to the rubber body 30, the distortion caused by the tensile force can be canceled out. For this reason, the rubber body 30
Since it is necessary to design the shaft joint by considering only the shear deformation of the shaft joint, it is possible to obtain a shaft joint that allows a larger bending angle than conventional joints. FIG. 11 is a perspective view showing a conical flange according to a third embodiment of the present invention. In the figure, in this configuration, the mounting surface 38 where the adhesive plate contacts the conical flange 29 is constructed as a flat surface, making it easier to manufacture the adhesive plate. Note that the center of the mounting surface 38 is O.
The structure is such that it touches a spherical surface centered on a point. Next, FIG. 12 shows the fourth example of the elastic shaft joint according to the present invention.
FIG. 3 is a longitudinal cross-sectional view showing an example of the present invention, in which the input shaft is bent at an angle α around point O. In the figure, this configuration has a conical flange 40 at the end of the output shaft 39, a conical flange 42 at the end of the input shaft 41, and a rubber body 43 and an adhesive plate 44 between the conical flanges 40 and 42. A mounting screw 46 and a nut 47 are fixed to the adhesive plate 44 and sandwich the elastic block 45 consisting of
It is configured to be connected to conical flanges 40 and 42 by means of a plurality of conical flanges 40 and 42. Note that the portion of the conical surface of the conical flanges 40 and 42 corresponding to the center of the mounting screw 46 is configured to be in contact with a spherical surface centered at point O. The shape of the elastic block 45 is either a plurality of cylindrical shapes as shown in FIG. 8, or a donut shape. Furthermore, elastic block 4
When 5 is made into a plurality of cylindrical shapes, the joint surfaces between the conical flanges 40, 42 and the adhesive plate 44 are configured to be flat in order to facilitate manufacturing. In this configuration, the state of each member when the output shaft 41 is bent is almost the same as in the embodiment shown in FIG. Therefore, conical flange 4
The amount of change in the interval between 0 and 42 is small, and the rubber body 43
The tensile strain generated in the process can be reduced. Therefore,
Tensile strain can be canceled by applying only a slight precompression to the rubber body 43, and a joint that allows a larger bending angle than conventional joints can be obtained. As explained above, according to the present invention, even when there is a relatively large bend between the input shaft and the output shaft, the connecting portion of each shaft is located at the same central point centered on the bend center point of the shaft center. Because of the spherical surface, no tensile force is generated in the rubber part, or the tensile force in the rubber part can be kept to a relatively small value, so a large bending angle can be tolerated. Furthermore, since there is almost no change in the distance between the joint surfaces with the elastic block, there is an effect that problems such as falling of the elastic block are eliminated.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a conventional elastic joint, Fig. 2 is a front view of Fig. 1, Fig. 3 is a longitudinal cross-sectional view showing the bent state of the elastic joint of Fig. 1, and Fig. 4 is a longitudinal cross-sectional view of a conventional elastic joint. 5 is a longitudinal cross-sectional view showing another conventional example of the shaft joint, FIG. 5 is a cross-sectional view taken along line E-E in FIG. 4, FIG. The figure is a longitudinal cross-sectional view showing one embodiment of the elastic shaft joint according to the present invention.
The figure is a front view of FIG. 7, FIG. 9 is a longitudinal sectional view showing the bent state of the elastic shaft joint of FIG. 7, and FIG. 10 is a bent state of the second embodiment of the elastic shaft joint according to the present invention. 11 is a perspective view showing a conical flange of the third embodiment of the elastic shaft joint according to the present invention, and FIG. 12 is a longitudinal sectional view showing the fourth embodiment of the elastic shaft joint according to the present invention.
FIG. 3 is a vertical cross-sectional view showing a bent state of the embodiment. 18, 28, 39... Output shaft, 19... Spherical flange, 20, 30, 43... Rubber body, 21, 3
1, 44... Adhesive plate, 22 , 32 , 45 ... Elastic block, 23, 33, 41... Input shaft, 24,
26... Spherical plate, 27, 37... Projection, 29,
40, 42... Conical flange, 34, 36... Conical plate.

Claims (1)

[Claims] 1. In an elastic shaft coupling that connects corresponding shafts via elastic bodies and transmits power by allowing bending of the shaft centers between the shafts, either Spherical parts having the same center point centered around the bending center point of the axis are formed on one shaft side by bulging in the same direction, and at least a part of the circumferential direction of each of the spherical parts is formed. A flange portion having a spherical surface centered on the center point forming a joint surface with an elastic block is provided, and an elastic block is provided between the flange portions of each shaft so as to be capable of transmitting power. Shaft coupling.