JPH032738Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a shaft coupling for transmitting rotational force, especially when the axes of the driving shaft and the driven shaft do not exactly match. The transmission loss is also small,
The main part of the flexible flat plate that forms this is related to a shaft joint that has a structure to prevent buckling deformation and can smoothly transmit rotational force without so-called buckling.

(b) Prior art The conventional shaft couplings used for this type of application are flexible ones that utilize the elasticity of rubber or synthetic coil springs, and mechanical ones that utilize the elasticity of rubber. There are so-called Oldham joints.

(c) Problems to be solved by the invention However, conventional products using elasticity such as rubber tend to twist in the direction of rotation, products made of synthetic springs have a small tolerance for misalignment, and mechanical products have a so-called There are drawbacks such as bumps occurring.

(d) Means for Solving the Problems The present invention eliminates these drawbacks and, despite its great flexibility, has little torsional deflection and has a simple structure that makes it compact, inexpensive, and highly practical. This provides a unique joint.

That is, two opposing sides of a floating member made of a flexible material into a cross-shaped flat plate are bent in the same direction, this is joined to one joint member, and the other two sides are bent in the opposite direction to the former. The structure is such that it is bent to the side and joined to the other joint member, and a protrusion in the plate thickness direction is provided by drawing on the flat part that becomes the center base of each side bent in both directions. A groove is provided in the bent part to average stress, resulting in a structure that eliminates so-called backlash and provides a long service life.

(e) Operation By configuring as described above, the two sets of opposing surfaces are respectively bent in the right angle direction, thereby absorbing the misalignment between the drive shaft and the driven shaft.

In addition, there is a drawing process to prevent buckling at the center of the flat part that forms the central base of the cross, but each side has flat parts around it, and each side bends arbitrarily in the axial direction of the joint. Bending deformation when both axes are not parallel can also be absorbed. However, in the direction of rotation, the rigidity is high because force is applied in the width direction of each side, and there is a drawing process to prevent buckling against torsional stress in this case, so the rotation angle error is extremely small.

(f) Examples The invention will be explained below with reference to the figures.

FIG. 1 is a perspective view showing the structure of an embodiment of the present invention.

In FIG. 1, a floating body 1 is made of a flexible material and is formed into a cross shape, and two opposing sides 2 and 3 are bent in the same right angle direction to form connecting parts 4 and 5. It is joined to one joint member 6.

Further, the other two sides 7 and 8 are bent in a right angle direction opposite to the above-mentioned sides 2 and 3 to form connecting portions 9 and 10, and are joined to the other joint member 11. A drive shaft 12 and a driven shaft 13 are fixed to the joint members 6 and 11, respectively. In addition, there are 18 driving grooves in the perpendicularly bent portions of each side 2, 3, 7, and 8 of the floating body 1.
At the base of each side are flat parts 14, 15, 16, 17.
is provided, and a protrusion 20 formed by circular extrusion and drawing is provided at the center thereof. In this state, when trying to transmit rotational force from the drive shaft 12 to the driven shaft 13, the force is transmitted from the joint 6 to the joints 4 and 5, to the flat part of the floating body 1, to the joints 9 and 10, to the joint. It will be passed on to 11. During this time, all forces are applied in the width direction of the cross section of each part. Therefore, when the width of the cross section of each part is W and the thickness is t, the moment of inertia of area I ₁ is I ₁ =1/12・W ³ t (1) In this case, W is the thickness t Since it is very large compared to , the value of the second moment of area I is large, and the deflection in the direction of rotation, that is, the rotation angle error, which is inversely proportional to this, is very small. 2 and 3 are side views showing the function of the flexible shaft joint of the present invention.

As shown in FIG. 2, a driving shaft 12 and a driven shaft 13
If the center of the connecting part 5,
Bending force is applied alternately to 6, 9, and 10. In addition, when the driving shaft 12 and the driven shaft 13 are bent by an angle d, the flat parts 14, 1 of the floating body 1
5 or 16 and 17 are bent alternately as shown in FIG. However, the formula for the second moment of area in these cases is I ₂ =1/12·t ³ W (2) because the direction in which the force is applied is in the thickness direction.

As an example, if the width W is 10 mm and the thickness t is 0.3 mm, the second moment of area I ₁ when transmitting the rotational force mentioned above is I ₁ = 1/12・10 ³ ×0.3 = 25 mm ⁴ Become.

On the other hand, in the case of deflection due to misalignment and bending, as shown in equation (2), I ₂ = 1/12 0.3 ³ × 10 = 0.0225 mm ⁴ In this example, the ratio of I ₁ and I ₂ is more than 1000, and the rotational force You can understand the magnitude of the ratio of the deflection strength when transmitting to the center and the ease of deflection with respect to misalignment and bending. Further, at the center of the flat part of the cross-shaped central base, there is a protrusion 20 in the thickness direction formed by circular drawing. This is to prevent the so-called cicada phenomenon, which is caused by the rotational force of this part, which causes a transmission angle error.

When using a flat plate-shaped material, the outer side of the board is stretched due to the bending process, and the board thickness becomes slightly thinner. This is done to increase the rigidity of this part, and to even out the torsional stress of each part due to rotational force transmission, resulting in a long-life model.

(g) Effects of the invention As is clear from the above explanation, the flexible shaft joint of the invention has an extremely simple structure and skillfully absorbs misalignment and angular errors between the drive shaft and driven shaft, Due to the effect of the grooves 18, the rigidity in the direction of rotational angle is very high and there is no buckling.It has performance far exceeding the conventional level and can be widely applied in the future, and its practical effects are extremely remarkable.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of an embodiment of the present invention, and FIGS. 2 and 3 are side views showing the operation of the present invention. 1... floating body, 4, 5, 9, 10... connecting part,
6, 11...Joint member, 12...Drive shaft, 13...
... Driven shaft, 18 ... Drive groove, 20 ... Protrusion.

Claims (1)

[Scope of utility model registration request] It is formed using a cross-shaped plate-like flexible material, two opposing sides are bent in the same direction to connect it to one joint member, and the other two sides are bent in the opposite direction to the two sides to connect it to the other joint member. A protrusion in the board thickness direction is provided at the center of the cross shape, and each two facing
A flexible shaft joint characterized by having a driving groove in the bent part of the side.