JP4753977B2 - Alignment mechanism - Google Patents

Description

  The present invention relates to an alignment mechanism for automatically aligning a shaft member supported by a bearing member.

Conventionally, as this type of alignment mechanism, for example, those shown in Patent Documents 1 and 2 are known. This aligning mechanism fits a metal bearing member with a convex curved surface on the outer periphery and a metal aligning member with a concave curved surface on the inner periphery, and the both convex and concave curved surfaces slide directly. Thus, the bearing member and the alignment member are configured to be relatively rotatable.
During the aligning operation when aligning the shaft member, the frictional force on the sliding surface between the relatively rotating bearing member and the aligning member becomes a sliding resistance, which acts as a starting torque for the aligning operation. .

  In the conventional aligning mechanism as described above, the concave curved surface and the convex curved surface slide when the bearing member and the aligning member relatively rotate. Even if the convex curved surface slides, if the two curved surfaces are exactly coincident with each other, the relative rotation is not possible. Strictly speaking, there is a slight gap between the two curved surfaces. A conventional alignment mechanism in which this gap exists will be described with reference to FIG.

  FIG. 14 is a cross-sectional view taken along a plane orthogonal to the axis of the shaft member 1 in the conventional alignment mechanism described above. That is, this alignment mechanism supports the shaft member 1 rotatably with the bearing member 2 and fits the alignment member 3 to the outside of the bearing member 2. The inner peripheral surface of the aligning member 3 is a concave curved surface 3a, and the outer peripheral surface of the bearing member 2 is a convex curved surface 2a. However, since the concave curved surface 3a and the convex curved surface 2a are respectively curved in the axial direction of the shaft member 1, that is, in a direction orthogonal to the paper surface of the drawing, the curvature is not shown in FIG.

  Further, FIG. 14 shows a state in which a load F is applied to the shaft member 1 in the direction of the arrow in the figure, and the minute gap between the bearing member 2 and the alignment member 3 is biased. Thus, when the load F acts on the shaft member 1, the minute gap between the bearing member 2 and the alignment member 3 is biased, and the bearing member 2 has only a slight contact portion A below the alignment member. 3, and the other parts are not in contact with the aligning member 3.

  In FIG. 14, the gap between the bearing member 2 and the aligning member 3 is shown to be extremely large, but in actuality, in this way, between the outer periphery of the bearing member 2 and the inner periphery of the aligning member 3. A large gap is not created, but a small gap as a whole. However, even if a minute gap is uniformly formed on the outer periphery of the bearing member 2 in a state where no load is applied to the shaft member 1, if the gap is formed unevenly by the load F, the shaft member 1 In the contact portion A in the load direction, the gap is zero, and on the opposite side, the gap is large, and the alignment member 3 and the bearing member 2 are hardly in contact with each other, and no sliding resistance is generated.

In this state, if the aligning mechanism performs aligning operation and the bearing member 2 and the aligning member 3 rotate relative to each other, the friction on the sliding surfaces of the members 2 and 3 in the portion A will be described. The force becomes a resistance force of the rotation, and acts as a starting torque during the alignment operation.
That is, even if the sliding resistance between the bearing member 2 and the aligning member 3 becomes the starting torque for the aligning operation, actually, only the contact portion between the two very narrow members corresponding to the load direction is used. This means that the sliding resistance dominates the starting torque.

On the other hand, when each member expands and contracts due to a change in environmental temperature and the dimensions of the bearing member 2 and the aligning member 3 change, a minute gap between the bearing member 2 and the aligning member 3 becomes large. , May get smaller.
For example, when the minute gap becomes small due to environmental temperature change, the contact range of the portion A where the bearing member 2 is strongly pressed against the aligning member 3 increases, and the sliding resistance increases accordingly. That is, the starting torque at the time of alignment increases.
On the contrary, when the minute gap becomes large, the contact portion between the bearing member 2 and the aligning member 3 becomes small, and the sliding resistance becomes small. As a result, the starting torque at the time of aligning becomes small.
JP 2002-310139 A JP 2006-125460 A

As described above, the conventional aligning mechanism has a problem that the starting torque at the time of aligning greatly changes due to the environmental temperature change.
An object of the present invention is to realize a self-aligning mechanism in which the variation in the starting torque is small even when the environmental temperature changes.

The first invention, the outer peripheral side of the bearing member so Awa fitted with a centering member, exert centering function by the shaft receiving member and the aligning member is relatively rotated via the convex surface and concave surface An alignment mechanism, wherein either one of the bearing member or the alignment member is constituted by a main body and a cap, and the main body is the other of the bearing member or the alignment member. On the surface facing the fitting surface of the member, the first concave curved surface curved in the axial direction of the shaft member supported by the bearing member, and adjacent to the first concave curved surface, the maximum diameter portion of the first concave curved surface And a positioning step on the opening side of the insertion hole, and a clamping step at the boundary between the insertion hole and the first concave curved surface. The cap has a flange formed on the outside and a tip of the cap. An annular convex portion, and a second concave curved surface that is continuous with the first concave curved surface and has the same curvature as the first concave curved surface, and is a boundary portion between the first and second concave curved surfaces, While provided with an elastic member holding part that incorporates a rubber O-ring between the opposed parts of the annular convex part and the clamping step part, the fitting surface of the other member of the bearing member or the aligning member has the above-mentioned A convex curved surface having substantially the same curvature as the first and second concave curved surfaces is formed, the O-ring is abutted against the clamping step, the annular convex portion of the cap is inserted into the insertion hole, and the O-ring While the flange portion is disposed opposite the positioning step portion with a gap between the tip of the annular convex portion, a welding portion is provided on the facing surface between the main body and the cap, and ultrasonic vibration is applied to the cap. As the welded part melts, Along with melting, the cap enters the inside of the main body, the flange portion is brought into contact with the positioning step portion, the O-ring is sandwiched between the annular convex portion and the clamping step portion, and the convex curved surface and the concave portion are It is characterized in that the O-ring holding elastic force is interposed between the curved surface .

The rubber includes natural rubber, resin rubber, elastomer and the like .

In addition, the said 1st concave curved surface and the 2nd concave curved surface are "making the curvature the same" means that the 1st concave curved surface and the 2nd concave curved surface are made into the state which can be regarded as one curve smoothly. is there.
In addition, the phrase “the curvatures of the first and second concave curved surfaces and the curvature of the convex curved surfaces are made substantially the same” means that the concave curved surface and the convex curved surface do not completely coincide with each other, but an elastic member is provided between the two members. It is a state in which the curvature of the concave curved surface and the curvature of the convex curved surface are slightly different in a state in which a slight gap that allows both members to rotate relative to each other is held.

In the first invention, since an elastic member that exerts an elastic force is interposed between the fitting surfaces of the aligning member and the bearing member, it is assumed that the minute gap between the bearing member and the aligning member has changed. However, the elastic member comes into contact with the convex curved surface and the concave curved surface within the range of the elastic force of the elastic member. Therefore, even if the environmental temperature changes and the gap between the convex curved surface and the concave curved surface changes, the starting torque during the alignment operation is determined by the elastic force of the elastic member. Thus, the starting torque at the time of alignment is determined not by the size of the gap between the convex curved surface and the concave curved surface but by the frictional force resulting from the elastic force of the elastic member, so even if the environmental temperature changes, There is little fluctuation in the starting torque of the aligning operation.

Moreover , since the member which forms a concave curved surface is comprised by two members, a main body and a cap, it becomes easy to incorporate an elastic member. In addition, since the convex curved surface of the other member can be fitted into the concave curved surface before the cap is attached to the main body, when fitting the bearing member to the aligning member, one member is forced to the other member. There is no need to push in, and the fitting operation becomes easy.

1 and 2 show a first embodiment of the present invention.
The alignment mechanism of 1st Embodiment consists of the bearing member 2 which supports the shaft member 1 rotatably, and the alignment member 6 fitted to the outer peripheral side, as shown in FIG.
The bearing member 2 is provided with a convex curved surface 2a that is curved in the axial direction of the shaft member 1 on the outer periphery thereof in the same manner as that used for a conventional aligning member. The convex curved surface 2a becomes a fitting surface on the bearing member side of the present invention.
In addition, the convex curved surface 2a of the bearing member 2 shown in FIG. 1 is not a complete circular arc, but forms a flat portion in a slight range at the center of the convex curved surface for the following reason.

That is, when forming the bearing member 2 having the convex curved surface 2a, two molds divided in the axial direction are used near the center of the convex curved surface 2a. When the bearing member 2 is formed using such a mold, burrs are generated at the joint portion of the mold. Such burrs must be removed by polishing after molding. However, as shown in FIG. 1, when a flat part is formed at the center and the boundary between the flat part and the arc is a joint part of the mold, burrs can be almost eliminated, and the deburring process Can be omitted.
However, in order to make the bearing member 2 rotate more smoothly with respect to the aligning member 6, the convex curved surface 2a is preferably a complete arc. Therefore, the flat portion is not necessarily an essential component in the present invention. It will not be.

On the other hand, the alignment member 6 of the first embodiment is configured by combining the main body 4 and the cap 5 as shown in FIG.
The main body 4 forms a first concave curved surface 4a for fitting the convex curved surface 2a of the bearing member 2 and an insertion hole 4b adjacent to the first concave curved surface 4a. As shown in FIG. 1, the insertion hole 4b has a larger diameter than the maximum diameter portion of the first concave curved surface 4a, and a clamping step 4c is formed at the boundary between the insertion hole 4b and the first concave curved surface 4a. To be formed. As shown in FIG. 1, the clamping step 4 c formed in this way is a top portion that becomes the maximum diameter portion of the convex curved surface 2 a of the bearing member 2 when the bearing member 2 and the alignment member 6 are combined. Have a corresponding relationship.

The insertion hole 4b has a concave curved surface whose inner peripheral surface maintains the same inner diameter with respect to the axial direction, and a positioning step 4d is formed on the opening side of the insertion hole 4b. ing.
The cap 5 incorporated in the main body 4 has a flange portion 5c formed on the outside thereof, and an annular convex portion 5b formed on the tip side thereof, and the annular convex portion 5b is inserted into the insertion hole 4b. . When the flange portion 5c comes into contact with the positioning step portion 4d, the tip of the annular convex portion 5b and the sandwiching step portion 4c of the main body 4 are in a relationship of facing each other while maintaining a predetermined distance. The interval is the elastic member holding portion 8. As is apparent from FIG. 1, the elastic member holding portion 8 formed in this way is in a relationship positioned at the center of the convex curved surface 2 a of the bearing member 2.

  Further, the second concave curved surface 5a is formed inside the cap 5, but when the annular convex portion 5b of the cap 5 is inserted into the insertion hole 4b as described above, the second concave curved surface 5a is The first concave curved surface 4a and the second concave curved surface 5a have the same curvature. The curved surface is continuous with the first concave curved surface 4a with the elastic member holding portion 8 interposed therebetween. In addition, the curved surface in which the first and second concave curved surfaces 4 a and 5 a formed in this way have the same curvature as that of the convex curved surface 2 a of the bearing member 2.

Therefore, by fitting the convex curved surface 2a of the bearing member 2 to the curved portion where the first and second concave curved surfaces 4a and 5a are continuous, the bearing member 2 can be rotated along the convex curved surface 2a.
Further, as described above, the elastic member holding portion 8 is formed by inserting the cap 5 into the insertion hole 4b. The elastic member holding portion 8 includes an O-ring which is an elastic member of the present invention. 7 is inserted, and the elastic force of the O-ring 7 is applied to the convex curved surface 2a.

Below, the process of fitting the bearing member 2 in the aligning member 6 composed of the main body 4 and the cap 5 and assembling the aligning mechanism will be described.
First, an O-ring 7 which is an elastic member of the present invention is fitted so as to abut on the clamping step 4c of the main body 4 from the insertion hole 4b side where the cap 5 is not attached.
Next, the bearing member 2 is inserted so that the O-ring 7 is slightly expanded from the inner peripheral side thereof, and the first concave curved surface 4 a of the main body 4 and the convex curved surface 2 a of the bearing member 2 are made to face each other.

Further, the annular convex portion 5b of the cap 5 is inserted into the insertion hole 4b, and the flange portion 5c is disposed opposite to the positioning step portion 4d. At this stage, there is a gap between the O-ring 7 butted against the clamping step 4c and the tip of the annular convex portion 5b of the cap 5.
When an ultrasonic vibration device is applied to the cap 5 in the above state to apply ultrasonic vibration, the welded portions 9 are sequentially melted and the cap 5 advances into the main body 4. When the cap 5 advances with melting and the flange portion 5c comes into contact with the positioning step portion 4d, the application of the ultrasonic vibration is stopped. As a result, the cap 5 is welded to the main body 4, and the O-ring 7 is sandwiched between the tip of the annular convex portion 5b of the cap 5 and the clamping step 4c of the main body 4, and the elastic member holding portion. 8 is formed.

  In the assembling step, the O-ring 7 is inserted into the main body 4 of the aligning member 6 and then the bearing member 2 is inserted. However, after the bearing member 2 is fitted into the main body 4, the main body 4 is inserted. An O-ring 7 may be fitted between the bearing member 2 and the bearing member 2. In short, if the O-ring 7 and the bearing member 2 that are elastic members are assembled to the main body 4 in which the cap 5 is not fitted, the alignment mechanism can be easily assembled.

The operation of the alignment mechanism of the first embodiment will be described.
In this alignment mechanism, the case where a load F acts on the shaft member 1 is shown in the cross-sectional views of FIGS.
Even in the alignment mechanism of the first embodiment, when the load F acts on the shaft member 1, the bearing member 2 moves together with the shaft member 1 in the load direction with respect to the alignment member 6. Accordingly, in FIG. 1, a gap is formed between the convex curved surface 2a on the upper side of the bearing member 2 and the concave curved surfaces 4a and 5a of the aligning member 6, but the O-ring 7 is in contact with the convex curved surface 2a. .

On the other hand, the O-ring 7 is compressed in the elastic member holding portion 8 below the bearing member 2, but the O-ring 7 is in contact with the convex curved surface 2 a of the bearing member 2. FIG. 2 is a sectional view passing through the center of the O-ring 7. As shown in FIG. 2, the O-ring 7 is in contact with the convex curved surface of the bearing member 2 on the entire inner periphery thereof.
In this state, when the gap between the aligning member 6 and the bearing member 2 becomes narrower or wider as a whole due to environmental temperature changes, the O-ring 7 is deformed. The situation of contacting the convex curved surface 2a over the entire circumference in the range of the elastic force does not change. Therefore, even if the environmental temperature changes, the O-ring 7 is always in contact with the bearing member 2 within the range of the elastic force, so that the variation in the starting torque during alignment is small.

In addition, although the bearing member 2 of the said 1st Embodiment is a sliding bearing, the bearing member of this invention is not restricted to a sliding bearing. For example, a ball bearing may be used as the bearing member as in the second and third embodiments shown in FIGS.
The second embodiment shown in FIG. 3 is different from the first embodiment in that the bearing member 10 is a ball bearing, but the other configuration is the same as that of the first embodiment. Therefore, the same reference numerals as those in FIG. 1 are used for the same components as those in the first embodiment, and detailed description thereof is omitted.

In the bearing member 10 of the second embodiment, the inner ring 10a is fixed to the shaft member 1, and the outer circumference of the outer ring 10b with a ball interposed between the inner ring 10a and the outer ring 10b is the same as the bearing member 2 of the first embodiment. The convex curved surface 10c is formed. And between the 1st concave curved surface 4a and the 2nd concave curved surface 5a formed in the inner periphery of the alignment member 6 same as 1st Embodiment, and the said convex curved surface 10c, O ring 7 which is an elastic member of this invention The entire circumference of the O-ring 7 is always in contact with the convex curved surface 10c.
Therefore, as in the first embodiment, the start-up torque during alignment is small and stable due to the eccentricity of the bearing member 10 and the temperature change.

In the third embodiment shown in FIG. 4, the bearing member 11 is a ball bearing. The bearing member 11 includes an inner ring 11a fixed to the shaft member 1 and an outer ring 11b, and an outer periphery of the outer ring 11b. Further, another interposed member 11c is attached and integrated. And the convex curved surface 11d used as the fitting surface by the side of the bearing member 11 is formed in the outer periphery of this interposition member 11c.
Other configurations and operations are the same as those of the second embodiment shown in FIG.
Accordingly, the sliding resistance between the entire inner circumference of the O-ring 7 and the convex curved surface 11d of the bearing member 11 is hardly affected by the environmental temperature, and the start-up torque fluctuation during alignment is small.

In the first to third embodiments, a concave curved surface is formed on the fitting surface of the aligning member 6, and the aligning member 6 is composed of two parts, the main body 4 and the cap 5. The O-ring 7 that is a member is easily fitted between the alignment member 6 and the bearing member 2.
However, the aligning member 6 may not be composed of the main body 4 and the cap 5 but may be one member from the beginning. In that case, the bearing member 2 must be forcibly pushed into the aligning member 6, and therefore at least one of the two members needs to be formed of a material that is greatly elastically deformed when assembled.
Further, contrary to the first to third embodiments, a concave curved surface may be formed on the bearing member, and a convex curved surface may be formed on the alignment member.

In the fourth embodiment shown in FIG. 5, the bearing member 14 includes a main body 12 and a cap 13. The main body 12 is formed with a first concave curved surface 12a, and the cap 13 is formed with a second concave curved surface 13a having the same curvature as the first concave curved surface 12a. The first and second concave curved surfaces 12a and 13a constitute a concave curved surface of the fitting surface on the bearing member 14 side. Moreover, while forming the elastic member holding | maintenance part 16 between the said main body 12 and the cap 13, the O-ring 7 which is an elastic member of this invention is incorporated there.
In FIG. 5, reference numeral 15 denotes an aligning member. The aligning member 15 includes a first concave curved surface 12 a formed on the main body 12 of the bearing member 14 and a second concave curved surface formed on the cap 13. A convex curved surface 15a having substantially the same curvature as that of 13a is formed.

The assembly process of the alignment mechanism of the fourth embodiment is as follows.
First, the O-ring 7 is fitted to the main body 12 without the cap 13 being fitted to the main body 12 of the bearing member 14. Next, the aligning member 15 is fitted to the outer periphery of the bearing member 14, and the first concave curved surface 12a and the convex curved surface 15a of the aligning member 15 are opposed to each other.
Further, the cap 13 is combined with the main body 12, and the two are welded and joined at the welded portion 17, thereby forming the bearing member 14.

In the aligning mechanism thus completed, the inner periphery of the O-ring 7 exhibits an elastic force against the convex curved surface 15a of the aligning member 15 over the entire periphery. Therefore, even if the bearing member 14 is eccentric with respect to the alignment member 15 due to the load acting on the shaft member 1 or the member expands and contracts due to a change in environmental temperature, the O-ring 7 does not protrude over the entire circumference. The state in contact with the curved surface 15a can be maintained.
Therefore, even if the bearing member 14 is decentered or the member contracts due to a temperature change, the resistance variation during the relative rotation between the bearing member 14 and the aligning member 15 is small. That is, even when the environmental temperature changes, the variation in the starting torque during alignment is reduced.

Further, even when the fitting surface on the bearing member 14 side is a concave curved surface as in the fourth embodiment, the O-ring 7 which is an elastic member can be formed by configuring the bearing member 14 with the main body 12 and the cap 13. The assembly of the aligning mechanism is easy as in the other embodiments. However, you may make it comprise the bearing member 14 by one member.
Furthermore, in the alignment mechanism of the fourth embodiment, either the O-ring 7 that is an elastic member or the alignment member 15 may be assembled first with respect to the main body 12 of the bearing member 14.
In short, of the alignment member and the bearing member, if the cap is assembled after the other member and the elastic member are assembled to the main body of the member having the concave curved surface and the main body and the cap, Assembling of the core member is facilitated.

It is sectional drawing of 1st Embodiment. It is the II-II sectional view taken on the line of FIG. It is sectional drawing of 2nd Embodiment. It is sectional drawing of 3rd Embodiment. It is sectional drawing of 4th Embodiment. It is sectional drawing of the aligning mechanism of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft member 2 Bearing member 2a Convex curved surface 4 Main body 4a 1st concave curved surface 5 Cap 5a 2nd concave curved surface 6 Alignment member 7 O ring 8 Elastic member holding part 9 Welding part 10 Bearing member 10c Convex curved surface 11 Bearing member 11d Convex curved surface 12 Main body 12a First concave curved surface 13 Cap 13a Second concave curved surface 14 Bearing member 15 Alignment member 15a Convex curved surface 16 Elastic member holding portion 17 Welding portion

Claims (1)

The outer peripheral side of the bearing member so Awa fitted with a centering member, there by aligning mechanism to exert centering function by the shaft receiving member and the aligning member is relatively rotated via the convex surface and concave surface And either one of the bearing member or the aligning member is composed of a main body and a cap, and is the main body, the fitting surface of the other member of the bearing member or the aligning member. A first concave curved surface that is curved in the axial direction of the shaft member supported by the bearing member and an insertion that is adjacent to the first concave curved surface and has a larger diameter than the maximum diameter portion of the first concave curved surface are provided on the opposing surfaces. A positioning step is formed on the opening side of the insertion hole, and a clamping step is provided at a boundary portion between the insertion hole and the first concave curved surface. And an annular protrusion formed on the tip side of the cap And a second concave curved surface that is continuous with the first concave curved surface and has the same curvature as the first concave curved surface, and is sandwiched between the annular convex portion and a boundary portion of the first and second concave curved surfaces An elastic member holding portion that incorporates a rubber O-ring is provided between the opposed portion to the stepped portion, and the fitting surface of the other member of the bearing member or the aligning member is provided with the first and second members. A convex curved surface having substantially the same curvature as the concave curved surface is formed, the O-ring is abutted against the clamping step, the annular convex portion of the cap is inserted into the insertion hole, and the O-ring and the annular convex portion are While the flange portion is disposed opposite to the positioning step portion with a gap between the tip and the positioning portion, a welding portion is provided on the facing surface between the main body and the cap, and ultrasonic vibration is applied to the cap to provide a welding portion. As the material melts, The cap is inserted into the main body, the flange portion is brought into contact with the positioning step portion, the O-ring is sandwiched between the annular convex portion and the sandwiching step portion, and between the convex curved surface and the concave curved surface. Alignment mechanism with the O-ring holding elastic force in the center

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