JPH07208491A - Oldham's coupling - Google Patents

Abstract

PURPOSE:To prevent rigidity lowering in a rotation direction to improve the transmission accuracy of a rotation position by forming constitution wherein an elastic protruded strip is provided on a shaft end side and only a simple recessed groove is provided on an intermediate member having low rigidity. CONSTITUTION:A recessed strip 5, wherein the rigidity of an elastic strip 4 does not become lower than the rigidity of an intermediate member 3, can be adopted when a substance having rigidity higher than that of plastic, e.g. metal, is used for jaw part 1a and 2a even plastic, etc., having small rigidity is used for the intermediate member 3. When an elastic projection 4 and a recessed groove 6 are fitted by an appropriate interference fit, the surface pressure between the elastic protruded strip 4 and the recessed groove 6 is equalized to eliminate local abrasion to moreover minimize rigidity lowering in a rotation direction, furthermore eliminating complex working. Moreover, the rigidity ratio between the elastic protruded strip and the intermediate member can be neared to the optimum value of 1 by adjusting the shape dimensions of the elastic protruded strip and the recessed strip on a rotation shaft end side, finally uniforming surface pressure distribution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure for mechanically transmitting the rotational position of a rotating shaft to a detector or the like.

[0002]

2. Description of the Related Art As a conventional example of this kind, a practical example is disclosed in
There is a universal joint disclosed in Japanese Patent No. 5532. This is shown in FIGS. 6 and 7. In FIG. 6, 1 and 2 are rotation axes, 1
Reference characters a, 2a are flanges, 3 is an intermediate member, 4 is a ridge inclined toward the outside, 5 is a groove, and 6 is a groove. FIG. 7 shows the shape of the intermediate member 3 in FIG. 7, the same symbols as those in FIG. 6 indicate the same parts.

Next, the operation of the universal joint will be described. In FIG. 6, the ridge 4 is appropriately narrowed so that the groove 6
When it is fitted in, the backlash in the rotational direction is reduced by properly absorbing the occurrence of backlash in transmitting the rotational force.

Another conventional example is Japanese Patent Laid-Open No. 59-59.
There is a joint structure disclosed in Japanese Patent Publication No. 19719. This is shown in FIG. 8, the same reference numerals as those in FIG. 6 indicate the same or corresponding portions.

Next, the operation of the joint structure will be described. In FIG. 8, when the elastic ridge 4 is inserted into the concave groove 6 by being tightly fitted, the elastic ridge 4 is coupled without play due to its elasticity.

[0006]

This type of universal joint uses a wear resistant low-rigidity member such as plastic for the intermediate member in order to absorb the misalignment between the rotary shafts by sliding the intermediate member. Often. In such a case, the above-mentioned actual development 5
In the universal joints disclosed in JP-A-7-5532 and JP-A-59-19719, since the elastic ridges are provided on the intermediate member having low rigidity, the rigidity in the rotating direction is further lowered,
It is used for the problem that the transmission accuracy of the rotational position of both rotary shafts cannot be improved when the transmission torque is increased, and it is used for coupling with a rotational position detector that outputs a signal of about 100,000 pulses per rotation even if the transmission torque is small. Then, there is a problem that the position transmission accuracy cannot be improved because the rigidity in the rotation direction is low. Further, in the joint structure disclosed in Japanese Utility Model Laid-Open No. 57-5532, an outwardly projecting ridge is formed, and the ridge is narrowed to fit into the groove. Therefore, at the tip of the ridge. Local surface pressure is generated, wear occurs due to the surface pressure,
Since it is difficult to absorb backlash over a long period of time and the ridge is narrowed to fit into the groove, only a low-rigidity member such as rubber can be used for the ridge, so that each rotation When it is used in combination with a rotational position detector that outputs a signal of about 100,000 pulses, there is a problem that the positional transmission accuracy cannot be improved because the rigidity in the rotational direction is low.

The present invention has been made in order to solve the above problems, reduces backlash and backlash in the rotation direction, has a long life, and reduces the decrease in rigidity in the rotation direction. The purpose is to obtain an Oldham coupling that can be used for coupling with a rotational position detector that outputs a signal of 10,000 pulses or more.

[0008]

According to the Oldham's joint of the first invention, an elastic ridge is provided in which a groove is provided in an intermediate member, and a ridge of a member attached to both ends of a rotary shaft forms a groove in the middle. It is configured so that

In the Oldham's joint of the second invention, at least one of both rotary shaft ends is formed so that the elastic protrusion is directly formed on the shaft end.

In the Oldham's joint of the third invention, at least one of the members attached to both ends of the rotating shaft has a shape that fits into the intermediate member.

The Oldham's joint of the fourth invention is constructed such that there are a plurality of pairs of elastic ridges formed on both rotary shaft end sides and concave grooves formed in the intermediate member.

[0012]

In the Oldham's joint of the first aspect of the invention, since the elastic ridge is provided on the shaft end side and the low-rigidity intermediate member has only a simple groove, a decrease in rigidity in the rotational direction is prevented. Moreover, local wear at the tip of the ridge can be prevented, and a long-life Oldham's joint with good rotational position transmission accuracy can be obtained.

In the Oldham's joint of the second aspect of the invention, at least one of both rotary shaft ends has an elastic ridge directly formed on the shaft end, so that the joint is formed while maintaining high rigidity in the rotational direction. Can be reduced and an inexpensive joint can be obtained.

In the Oldham's joint of the third aspect of the invention, since at least one of the members attached to both ends of the rotating shaft has a shape that fits into the intermediate member, the axial length is kept high while maintaining high rigidity in the rotating direction. The joint can be made shorter.

In the Oldham's joint of the fourth aspect of the invention, since a plurality of pairs of protrusions formed on both rotary shaft end sides and concave grooves formed on the intermediate member are provided, rigidity in the rotational direction can be increased and transmission of rotational position can be achieved. The accuracy can be further increased.

[0016]

【Example】

Example 1. An embodiment of the first invention will be described below with reference to FIG. In the drawing, reference numerals 1 and 2 denote rotary shafts, 1a and 2a denote flanges thereof, 3 denotes an intermediate member, 4 denotes elastic projections provided on the flanges 1a and 2a, 5 denotes concave projections provided on the elastic projections 4, Reference numeral 6 is a concave groove provided in the intermediate member 3.

Due to the above-mentioned structure, even if the intermediate member 3 is made of a plastic material having low rigidity, the collar portions 1a, 2
If a, which has a higher rigidity than plastic or the like, is used for a, it is possible to form the concave streak 5 such that the rigidity of the elastic projection 4 does not become smaller than the rigidity of the intermediate member 3. Therefore, when the elastic ridges 4 and the concave grooves 6 are fitted with an appropriate interference fit, the surface pressure between the elastic ridges 4 and the concave grooves 6 becomes uniform, local wear is eliminated, and the rigidity in the rotational direction is further improved. The decrease is also minimal. Moreover, complicated processing such as providing a ridge inclined toward the outside like the universal joint shown in FIG. 5 as a conventional example is unnecessary, and an inexpensive joint can be provided.

Example 2. Next, an embodiment of the second invention will be described with reference to FIG. 2, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts. Reference numeral 4a is an elastic ridge directly provided on the shaft end of the rotary shaft 1, and 5a is a concave ridge provided on the elastic ridge 4a.

With the above construction, it is not necessary to provide a flange at the end of the rotary shaft. Therefore, the number of members constituting the joint can be reduced, and a more inexpensive joint can be provided without impairing the function of the embodiment of the first invention.

Example 3. Next, an embodiment of the third invention will be described with reference to FIG. In FIG. 3, FIG. 1 or FIG.
The same reference numerals as in FIG. Reference numeral 2b is a flange portion of the rotary shaft 2 and has a shape to be inserted into the intermediate member 3a. Reference numeral 3b is a shape formed on the intermediate member 3a so that the collar portion 2b at the shaft end is inserted therein.

With the above construction, it becomes possible to shorten the axial length by the length of the flange portion at the end of the rotary shaft.
It is possible to provide a smaller joint without impairing the function of the embodiment of the invention.

Example 4. Next, an embodiment of the fourth invention will be described with reference to FIG. 4, the same reference numerals as those in FIGS. 1 to 3 denote the same or corresponding parts. Reference numeral 4b denotes a plurality of elastic ridges provided at the end of the rotary shaft, and 5b denotes a concave ridge provided on each elastic ridge 4b. Reference numeral 6b is a plurality of concave grooves provided in the intermediate member 3.

With the above structure, it is possible to increase the apparent rigidity of the elastic ridges in the rotational direction by a plurality of times.
It is possible to provide a joint with good rotational position transmission accuracy without impairing the function of the embodiment of the invention.

In the above embodiment, a solid member is used as the intermediate member, but in order to reduce the weight, etc.,
As shown in FIG. 5, the hollow intermediate member 3 a and the intermediate member 3
The present invention can be similarly applied to the elastic ridge 4 that fits the concave groove 6 formed in a.

[0025]

As described above, according to the Oldham's joint of the first aspect of the invention, since the elastic ridge is provided on the rotary shaft end side where the rigidity can be increased, the decrease in rigidity in the rotational direction is suppressed to the minimum and the rotational position is improved. The effect is that the transmission accuracy of can be improved. Moreover, the rigidity ratio between the elastic ridge and the intermediate member can be approximated to 1 by adjusting the shape dimensions of the elastic ridge and the concave ridge on the rotary shaft end side. Since the pressure distribution can be made uniform, local wear can be prevented and the joint life can be extended. Further, since the elastic ridge is not a ridge that is inclined outward, there is an effect that local wear at the tip of the ridge can be prevented and the joint life can be extended.

Further, according to the second aspect of the invention, since the elastic ridge on the shaft end side is directly formed on the shaft end, the number of parts constituting the joint can be reduced, and the rotational position transmission accuracy is good and long. It has the effect of obtaining an Oldham joint that has a long life and is inexpensive.

Further, according to the third aspect of the invention, since the shape of the member having the elastic ridge formed on the shaft end side is adapted to be inserted into the intermediate member, the axial length can be shortened and the rotational position can be reduced. It has the effect of obtaining a small Oldham coupling with good transmission accuracy and long life.

Furthermore, according to the fourth aspect of the present invention, since the elastic ridge and the plurality of concave grooves are provided in a plurality of pairs, the rigidity in the rotational direction can be further increased, the life is long, and the rotational position transmission is highly accurate. There is an effect that an Oldham joint with characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of an Oldham coupling according to an embodiment of the first invention.

FIG. 2 is a perspective view of an Oldham coupling according to an embodiment of the second invention.

FIG. 3 is a perspective view of an Oldham coupling according to an embodiment of the third invention.

FIG. 4 is a perspective view of an Oldham coupling according to an embodiment of the fourth invention.

FIG. 5 is a perspective view of an Oldham coupling according to a modified embodiment of the first invention.

FIG. 6 is an assembly diagram of a conventional Oldham coupling.

FIG. 7 is a shape view of an intermediate member of a conventional Oldham coupling.

FIG. 8 is an assembly diagram of a conventional Oldham coupling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotary shaft 2 rotary shaft 1a shaft end member 2a shaft end member 2b shaft end member 3 intermediate member 3a intermediate member 3b hollow part provided in the intermediate member 4 elastic projection 4a elastic projection 4b elastic projection 5 concave 5a concave Strip 5b Groove 6 Groove 6b Groove

Claims (4)

[Claims] 1. An intermediate member is located between both rotary shafts to be connected, a ridge is formed on a member attached to both rotary shaft ends, and concave grooves are formed on both sides of the intermediate member. In an Oldham's joint to be engaged between a ridge and a groove, an Oldham's joint in which a ridge of a member attached to both ends of a rotary shaft is an elastic ridge having a ridge formed in the middle. 2. The Oldham coupling according to claim 1, wherein at least one of both rotary shaft ends has an elastic ridge directly formed on the shaft end. 3. The Oldham's joint according to claim 1, wherein at least one of the members attached to both ends of the rotary shaft has a shape that fits into the intermediate member. 4. The Oldham's joint according to claim 2 or 3, wherein there are a plurality of pairs of protrusions formed on both rotary shaft end sides and concave grooves formed on the intermediate member.