JPH11201177A - Friction fastener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a friction fastener from rotating together with fastening bolts when the fastening bolts are fastened, in the friction fastener composed of an inner wheel fitted around a shaft, an external wheel inserted into a boss of a rotor, and a pair of side rings inserted from both sides of an axial direction between the inner and external wheels in a taper fitting condition, and a plurality of fastening bolts for fastening the side rings in an axial direction. SOLUTION: A cross section of an external wheel 2 is uniformly constituted along a circumferential direction, and a whole shape in a free condition is bent in a non-complete round state, and the inner circumferential surface of the external wheel 2 is brought into partially contact with an outer peripheral surfaces of a pair of side rings 3 in a circumferential direction in a condition in which fastening bolts 4 are not fastened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction fastener, and more particularly to a friction fastener for fixing a shaft and a rotating body attached thereto in a frictionally fastened state.

[0002]

2. Description of the Related Art As this kind of friction fastener, as shown in FIG. 8, an inner ring (1) for tightening a shaft (J) and a rotating body (M) are used.
Outer ring (2) inserted into the boss (B), a pair of side rings (3) (3) inserted between them in a tapered manner from both sides in the axial direction, and these side rings There are known friction fasteners comprising a plurality of tightening bolts (4) and (4) for fastening various types of rotating bodies (M) such as gears, pulleys, and rotary heads to the shaft (J). Many are used. The inner ring (1) and the outer ring
Each of (2) has a cutting slit (S) (not shown) at a part in the circumferential direction, and its diameter can be enlarged or reduced.

[0003] As shown in FIG.
(J) and then housed in the boss (B), and then tighten the tightening bolts (4) and (4) to cause the side rings (3) and (3) to face each other. Due to the action of the fitting part, the inner surface of the inner ring (1) is pressed against the shaft (J),
Conversely, since the diameter of the outer ring (2) increases,
The outer peripheral surface of (2) is pressed against the inner peripheral surface of the boss (B). Thus, the shaft (J) and the rotating body (M) are in contact with the shaft (J) and the inner ring (1), the contact between the side rings (3) and (3) and the inner ring (1), and the side ring. (3) Torque is transmitted via the frictional force between the contact portion between (3) and the outer ring (2) and the contact portion between the outer ring (2) and the inner peripheral surface of the boss.

However, in the prior art, in the initial stage of the tightening of the tightening bolts (4), the clearance between the shaft (J) and the inner ring (1) and between the outer ring (2) and the inner peripheral surface of the boss (B) is increased. Is not sufficiently pressurized, the tightening rotation of the tightening bolt (4) causes the fastener itself or the side ring (3) (3)
Rotate simultaneously, that is, a so-called corotation phenomenon is likely to occur. In particular, in order to secure the concentricity between the rotating body (M) and the shaft (J) in this kind of friction fastener and without any runout, it is necessary to adjust the tightening bolts (4). It is important to equalize the tightening force.In order to achieve this, it is necessary to gradually increase the degree of tightening of all tightening bolts (4) (4). However, there is a problem that the co-rotation phenomenon is apt to occur and workability at the time of fastening is poor.

[0005]

SUMMARY OF THE INVENTION The present invention relates to such an "inner ring (1) fitted on the shaft (J)" and a boss (B) of the rotating body (M).
Outer ring (2) and a pair of side rings (3) inserted between them in a tapered engagement from both axial sides
(3) and a plurality of tightening bolts (4) (4) for tightening these side rings in the axial direction ''), when tightening the tightening bolts (4) (4), Is to make it difficult for them to rotate together.

[0006]

In order to solve the above-mentioned problem, the solution of the present invention is as follows. "The cross section of the outer ring (2) is uniformly formed in the circumferential direction, but is free in a free state. The overall shape of the outer ring (2) is curved in a non-circular shape, and when the tightening bolts (4) and (4) are not tightened, the inner peripheral surface of the outer ring (2) has the pair of side rings ( 3)
(3) It is configured to partially contact the outer peripheral surface in the circumferential direction ”.

Here, the outer ring (2) can be enlarged in diameter by a method such as providing the cutting slit (S). The inner ring (1) can be reduced in diameter. This technical measure works as follows. The outer ring
Since the cross section of (2) is formed in a predetermined cross section required for frictional fastening, if a frictional fastener employing the above means is interposed between the boss (B) and the shaft (J). The outer ring (2), which partially contacts the outer peripheral surfaces of the side rings (3), (3), tends to be slightly pushed into the inner peripheral surface of the boss (B).

Since the outer ring (2) is non-circular, the apparent radial width corresponding to the run-out is between the side rings (3) and (3) and the inner peripheral surface of the boss (B). It tends to be forcibly pushed into. As a result, the side ring
(3) (3) is also pressed against the inner peripheral surface of the outer ring (2) pressed against the inner peripheral surface of the boss (B), and the side ring (3)
With respect to the rotation of (3), a state in which a frictional force acts on this portion tends to occur.

When the tightening bolts (4) and (4) are tightened in this state, the friction against the rotational force applied to the side rings (3) and (3) with the screwing rotation of the tightening bolts (4). Drag by force is likely to act.

[0010]

Since the present invention has the above configuration, it has the following specific effects. Between boss (B) and outer ring (2), and outer ring
(2) and side rings (3), (3)
(4) In the initial stage of the tightening in (4), the drag due to the frictional force easily acts on the rotational force, and the co-rotation described above hardly occurs.

Since the outer ring (2) is merely made to be non-circular to a predetermined degree, the structure for preventing the co-rotation is very simple. [Regarding Additional Improvements] * a In the above configuration, the boss (B) corresponding to the maximum diameter portion of the outer peripheral surface of the outer ring (2) in the non-tightened state of the fastening bolts (4) and (4). ) Is set to be larger than the inner diameter of the shaft.) When the rotating body (M) is mounted on the shaft (J), when this fastener is pushed into the boss (B) (or After pushing in the tightening bolt (4)
(4) is lightly closed in the specified temporarily tightened state), and the outer ring
The inner peripheral surface of (2) is on the outer peripheral surface of side rings (3) and (3), and the outer ring is
The outer ring (2) is elastically deformed from the free state so that the outer peripheral surface of (2) is lightly pressed against the inner peripheral surface of the boss (B).

Therefore, when the fastener is accommodated in the boss (B), the space between the inner peripheral surface of the boss (B) and the outer peripheral surfaces of the side rings (3) and (3) due to the elastic deformation ability of the outer ring (2) is obtained. Is generated sufficiently. Therefore, the effect of the invention is further ensured. Here, the non-tightened state means a predetermined temporary tightened state until the tightening bolts (4) and (4) reach the final tightened state.
The maximum diameter portion of the outer ring (2) when not accommodated in (B) is set to be larger than the inner diameter of the corresponding boss (B). * B section The “out-of-round state of the outer ring (2) may be a flat circle or an ellipse”. In this case, the longer diameter portion of the outer ring (2) contacts the inner peripheral surface of the boss (B), and the shorter diameter portion of the outer ring (2) contacts the outer peripheral surface of the side rings (3) (3). And the above effect is further improved. * C section Further, in the above-mentioned section b, "the outer ring (2) has a cutting slit at one of a portion corresponding to the minor axis of a flat circle or an ellipse.
(S) is formed, the diameter at the short diameter portion of the maximum diameter portion of the tapered surface on both sides in the axial direction is set to be larger than the minimum diameter portion of the side rings (3) (3) '', Since the width of the section of the cutting slit (S) is easily expanded, the fastener is changed to the boss (B).
When inserted into the boss (B), the short diameter is easily expanded and expanded by the side rings (3), (3), and the long diameter is easily reduced when pushed by the inner peripheral surface of the boss (B). 2)
Are easily elastically deformed. Therefore, the fastener (J)
It can be easily mounted at a predetermined position in the boss (B) while being externally fitted to the boss, and the effect of preventing the co-rotation is further improved. * D section In the above section c, "the flat circle or ellipse has a curvature (N ₁ ) larger than the curvature of each part of the outer ring (2) when the outer ring (2) is in a perfect circle state. In the case of `` a flat circle or an ellipse having a set portion, '' the outer ring (2) can be manufactured by rolling a strip having a predetermined cross section and a predetermined length to a predetermined curvature. The manufacture of the outer ring (2) is simple. * E section In the above section d, when the “outer ring (2) has a configuration in which the outer ring (2) is bent to the large curvature (N ₁ ) over the entire circumference and is maintained in a deformed state within the elastic limit”, Outer ring (2) side ring by tightening the tightening bolts (4) (4)
(3) When pressure is applied between (3) and the inner peripheral surface of the boss (B), each part of the outer ring (2) in the circumferential direction is elastically deformed. Becomes constant.

The above-mentioned structure: "The outer ring (2) is bent to the large curvature (N ₁ ) over the entire circumference, and is maintained in a deformed state within the elastic limit". Outer ring
(2) While bending a strip of a predetermined length having a cross section corresponding to the cross section to a curvature larger than the curvature of a circle having the predetermined length as a circumference, both ends of the strip are In this case, the entire outer ring (2) becomes a flat circle or an ellipse and the slit of the outer ring (2)
In the part (S), both ends are in close contact with each other.

[0014]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. The example shown in the exploded view of FIG.
The inner ring (1) and the outer ring (2) are both examples in which a strip having a predetermined cross section and a predetermined length is roll-bent to a predetermined curvature, and is manufactured.
In this example, the front shape of the outer ring (2) alone in the free state is
As shown in the front view of FIG. 2, the one whose curvature is substantially constant over the entire circumference is a shape deformed into a flat circle within the elastic limit.

[0015] Between the inner ring (1) and the outer ring (2),
Side rings (3) (3) formed in mutually symmetric shapes are interposed. The inner and outer peripheries of the side ring (3) are finished with tapered surfaces (31) and (32) having a small diameter portion on the inside.
As shown in FIG. 1, the cross section of the outer ring (2) has a flat trapezoidal shape protruding inwardly, and has a concave portion on the top thereof which is recessed on the outer side of the outer ring (2). The slope is inclined toward. Therefore, the outer ring (2) has a concave groove (21) corresponding to the concave part at the center of the inner periphery, and both sides thereof have tapered surfaces (22) and (22) which expand outward in the axial direction.
It has become. The taper value of the tapered surface (22) is made to match that of the tapered surface (32). And the outer ring
The cutting slit (S) provided in (2) is set in a waveform as shown in FIG.

As shown in FIG. 3, the outer ring (2) is provided with an upper roll (R ₁ ) and a lower roll
(R ₂₎ (R ₂₎ and is fabricated is bent in a ring shape by a roll bend were used. At this time, the groove (21) is the upper roll (R ₁₎ to from the roll bending in a state of fitted into the ribs (r) which is provided, the direction precision bending direction bending by the bending rolls is high not fluctuate worried It has been roll-bended.

In particular, regarding the outer ring (2), a perfect circle determined by the length of the strip (in this case, the boss (B)
The belt is roll-bent so as to have a curvature (N ₁ ) larger than the curvature (N ₀ ) of the inscribed circle), and to hit both ends of the strip. Accordingly, in the free state, the outer ring (2) is finished in a state in which there is an internal stress due to the contact, and as a whole each part is bent to the large curvature (N ₁ ), but mainly the cutting slit ( The curvature on the opposite side of S) is elastically deformed to a curvature smaller than the large curvature (N ₁ ).

The inner ring (1) also has a similar sectional structure.
The cross section is different only in that it is a flat trapezoidal shape convex on the outer peripheral side, and a concave groove (11) is provided at the central top of the cross section, and both sides thereof have a taper value of the tapered surface (31). The outer ring (2) is the same as the outer ring (2) in that it has a tapered surface (12) matched with the inner ring (1), and the inner ring (1) is also formed with high bending direction accuracy by roll bending. This inner ring (1)
It is finished to a perfect circle with a predetermined accuracy, and the cutting slit (S) has a circumferential width over the entire area of the inner ring (1).

The overall shape (front shape) of the outer ring (2) is formed as a flat circle as described above, but the minor diameter of the average diameter of the tapered surface (22) is
(3) is set to be smaller than that of the average diameter of the tapered surface (32) and larger than the diameter of the minimum diameter portion of the tapered surface (32);
The major axis of the outer peripheral surface of the outer ring (2) is set to a size substantially matching the internal diameter of the boss (B).

In short, as shown in FIG. 4, the radius difference between the minimum diameter (L ₁ ) of the short diameter part of the outer ring (2) and the maximum diameter (L ₂ ) of the long diameter part
(L) = (L ₂ −L ₁ ) / 2 is set so as to be larger than the radius difference (L ₀ ) between the outer peripheral surface of the side ring (3) and the inner peripheral surface of the boss (B). . The frictional fastener configured as described above is housed in the boss (B) of the rotating body (M) and penetrates one side ring (3) as shown in FIG. A plurality of tightening bolts (4) (4) screwed into screw holes provided in the other side ring (3) are tightened.

With this fastener externally fitted to the shaft (J), the boss
When inserted into (B), the outer ring (2) is assembled with the inner ring (1) and the side rings (3) (3) by a plurality of fastening bolts (4) (4) in a predetermined temporarily tightened state. At this time, since the short diameter portion of the outer ring (2) has the above-mentioned relationship with the outer peripheral surface of the side ring (3), the cutting slit (S) is in an enlarged state, and the outer ring (2) has The major axis of the outer peripheral surface is the boss (B)
Is larger than the inner diameter. Outer ring (2) in this state
When the long diameter portion of the outer peripheral surface is pushed in from both sides, the cutting slit (S) is enlarged, so that the long diameter is reduced and the fastener can be accommodated in the boss (B).

In the state immediately after the housing, the long diameter portion of the outer peripheral surface of the outer ring (2) is bossed by the elastic restoring force of the outer ring (2).
(B), and the short diameter portion of the inner peripheral surface of the outer ring (2) is pressed against the outer peripheral surfaces of the side rings (3, 3). Due to the frictional force associated with these pressing forces, the entire fastener has a predetermined turning resistance and the side ring (3)
(3) Rotational resistance is generated in itself. Therefore,
Even when the fastening bolts (4) and (4) are tightened in this state, the co-rotation can be prevented by the rotation resistance.

Tightening bolt in said temporarily tightened state
(4) If the tightening degree of (4) is loose, the outer ring (2) can be housed in the boss (B) without pushing in the long diameter part of the outer peripheral surface,
Thereafter, when the predetermined temporary tightening state is obtained by manual tightening,
Similarly, the outer ring (2) is housed in a state in which an elastic restoring force acts between the side ring (3) and the boss (B) to prevent corotation due to frictional force.

Since the outer ring (2) is formed by bending a strip having a uniform cross section and a predetermined length into a ring shape by roll bending, the tightening bolts (4) and (4) reach the final position. In the tightened state, each part of the outer ring (2) is pressed into a wedge shape between the side rings (3) (3) and the inner peripheral surface of the boss (B), and the outer peripheral surface of the outer ring (2) is formed. Of the outer ring (2) adheres to the inner surface of the boss (B), and the tapered surface (22) of the outer ring (2)
(3) The tapered surfaces (31) and (32) of (3) are in close contact with the whole area, and function similarly to the conventional one in terms of the friction fastening function.

In particular, in this example, since the curvature of the outer race (2) due to roll bending is set to a constant curvature, the outer race (2) is connected to the inner peripheral surface of the boss (B) and the side surface in the final tightening state. The ring (3) is easily sandwiched between the outer peripheral surface of the ring (3). The disadvantage that the internal stress is locally increased does not occur. Furthermore, the side ring of this embodiment
(3) The average diameter of the tapered surfaces (31) and (31) of (3) is set to be slightly larger (about 0.01 to 0.5 mm) than the average diameter of the tapered surface (12).

Therefore, in the initial stage of the tightening of the tightening bolts (4) and (4), the inner ring is moved by the side rings (3) and (3) facing each other.
The tapered surface (12) and the tapered surface (31) of (1) are in a pressurized state. Thereafter, when the tightening bolts (4) and (4) are further tightened, the side rings (3) and (3) are further opposed to each other, and the tapered surfaces (12) and (31) are fitted to each other by the fitting action.
(3) The diameter of (3) is enlarged, and the outer ring (2) is enlarged accordingly, and finally the outer ring (2) is pressed against the inner peripheral surface of the boss (B). .

In this final state, the pressing force per unit area for pressing the outer peripheral surface of the outer ring (2) against the inner peripheral surface of the boss (B) is based on the inner peripheral surface of the inner ring (1) and the surface of the shaft (J). The contact area between the outer ring (2) and the inner peripheral surface of the boss (B) is larger than the contact area between the inner ring (1) and the shaft (J). Rotating body even with small pressing force
The transmission torque to (M) becomes sufficiently large.

On the other hand, the side rings (3) and (3) have tapered surfaces.
(31) In the case where (32) comes into simultaneous contact with the tapered surfaces of the inner ring (1) and the outer ring (2), the pressing force between the inner ring (1) and the outer peripheral surface of the shaft (J) and the outer ring (2) and the inner peripheral surface of the boss (B) have the same pressing force.
Since the pressing force on the surface of the shaft becomes extremely large, the fastening force of the shaft (J) by the fastener becomes large. As a result, the axis (J)
The transmission torque from the rotor to the rotating body (M) is extremely large as compared with the conventional known one.

Experimentally, a transmission torque of about 1.3 to 2 times was able to be ensured when the same size was compared. At this time, the tightening torque of the tightening bolts (4) and (4) was almost the same as that of the conventional bolt. In the above embodiment, in the final tightening state, the outer ring (2) itself is deformed from the shape in the free state, but the degree of this deformation is within the elastic limit of the constituent material of the outer ring (2). Thus, the shape of the free state is determined. Therefore, when the fastening bolts (4) and (4) are loosened and the fastener is removed from the boss (B), the outer ring (2) is restored to a free state, so that the above-described co-rotation preventing effect can be obtained even when reused. .

[Other Embodiments] Apart from the first embodiment, the outer race (2) has an overall front shape as shown in FIG. 6 where a cutting slit (S) and an ellipse having a long diameter on the side opposite to the cutting slit (S). Alternatively, it may be formed in a flat circular shape. In addition to the elliptical or flat circle, when inserted into the boss (B), part of the outer peripheral surface elastically contacts the inner surface of the boss (B), and part of the inner peripheral surface (3) Any other non-circular shape such as an oval may be used as long as it is configured to elastically contact the outer peripheral surface.

In the above embodiment, the present invention is applied to a frictional fastener having a structure in which side rings (3) and (3) are interposed between an inner ring (1) and an outer ring (2). However, even in the case of a friction fastener in which the inner ring and the outer ring are directly taper-fitted and a plurality of tightening bolts are inserted therebetween, the outer ring may be formed into a non-circular shape. In this case, since the thickness of the outer ring is thicker than that of the outer ring (2) of the above-described embodiment, there is a possibility that the problem of the non-roundness may occur.

[Brief description of the drawings]

FIG. 1 is an exploded view of an embodiment of the present invention.

FIG. 2 is a perspective view of an outer ring (2).

FIG. 3 is an explanatory view of a method of bending the outer ring (2) by roll bending.

FIG. 4 is an explanatory view showing the relationship between the major axis and the minor axis of the flat circular outer ring (2).

FIG. 5 is an explanatory diagram (front view) of an initial stage of tightening of the tightening bolts (4) and (4) in a use state.

FIG. 6 is a front view of a final tightened state.

FIG. 7 is a perspective view of another example of the outer ring (2).

FIG. 8 is a sectional view of a conventional example in a final tightened state.

[Explanation of symbols]

(J): Shaft (1): Inner ring (M): Rotating body (B): Boss
(2): an outer ring (3): side rings (4): clamping bolts (S): cutting a slit (11) (21): the groove (R ₁₎ upper roll (R ₂₎ lower roller
r: the ribs (12) (22) (31) (32): the tapered surface (N ₀₎ (N _1): curvature (L _1): the minimum diameter portion (L _2): Maximum diameter section

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[Procedure amendment]

[Submission date] March 12, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

Therefore, when the fastener is accommodated in the boss (B), the space between the inner peripheral surface of the boss (B) and the outer peripheral surfaces of the side rings (3) and (3) due to the elastic deformation ability of the outer ring (2) is obtained. Is generated sufficiently. Therefore, the effect of the invention is further ensured. Here, the non-tightened state means a predetermined temporary tightened state until the tightening bolts (4) and (4) reach the final tightened state.
The maximum diameter portion of the outer ring (2) when not accommodated in (B) is set to be larger than the inner diameter of the corresponding boss (B). * B section The “out-of-round state of the outer ring (2) may be a flat circle or an ellipse”. In this case, the longer diameter portion of the outer ring (2) contacts the inner peripheral surface of the boss (B), and the shorter diameter portion of the outer ring (2) contacts the outer peripheral surface of the side rings (3) (3). And the above effect is further improved. * C section Further, in the above-mentioned section b, "the outer ring (2) has a cutting slit at one of a portion corresponding to the minor axis of a flat circle or an ellipse.
(S) is formed, the diameter at the short diameter portion of the maximum diameter portion of the tapered surface on both sides in the axial direction is set to be larger than the minimum diameter portion of the side rings (3) (3) '', Since the width of the section of the cutting slit (S) is easily expanded, the fastener is changed to the boss (B).
When inserted into the boss (B), the short diameter is easily expanded and expanded by the side rings (3), (3), and the long diameter is easily reduced when pushed by the inner peripheral surface of the boss (B). 2)
Are easily elastically deformed. Therefore, the fastener (J)
It can be easily mounted at a predetermined position in the boss (B) while being externally fitted to the boss, and the effect of preventing the co-rotation is further improved. * D section In the above section c, "the flat circle or ellipse has a curvature (N ₁ ) larger than the curvature of each part of the outer ring (2) when the outer ring (2) is in a perfect circle state. In the case of `` a flat circle or an ellipse having a set portion, '' the outer ring (2) can be manufactured by rolling a strip having a predetermined cross section and a predetermined length to a predetermined curvature. The manufacture of the outer ring (2) is simple. * E section In the above section d, the outer ring (2) is bent to the large curvature (N ₁ ) over the entire circumference, and the outer ring (2) is in a free state in the final tightening state of the tightening bolts (4) and (4). Is deformed within the elastic limit from the shape of the outer ring '', the outer ring (2) is tightened with the tightening bolts (4) (4).
Is pressed between the side rings (3) and (3) and the inner peripheral surface of the boss (B), each part of the outer ring (2) in the circumferential direction is pressed while being elastically deformed. The degree of elastic deformation is constant.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

The above structure: "The outer ring (2) is bent to the large curvature (N ₁ ) over the entire circumference, and the outer ring (2) is in a free state in the final tightening state of the tightening bolts (4) (4). A configuration in which the band is deformed within the elastic limit from the shape of the outer ring (2) means a circle having a predetermined length as a circumference having a predetermined length of a strip having a cross section corresponding to the cross section of the outer ring (2). This is a case where the outer ring (2) itself is deformed from a shape in a free state in a state where the outer ring (2) itself is elastically deformed so that both ends of the band plate are in close contact with each other while being bent to a curvature larger than the curvature of the band plate. In this case, the shape of the free state is determined so that the degree of deformation is within the elastic limit of the constituent material of the outer race (2).

Claims (6)

[Claims] An inner ring (1) externally fitted to a shaft (J), and a rotating body
The outer ring (2) inserted into the boss (B) of (M), a pair of side rings (3) and (3) inserted between them in a tapered state from both axial sides, and these side rings A frictional fastener comprising a plurality of tightening bolts (4) and (4) for tightening in the axial direction, wherein the outer ring (2) has a uniform cross section in the circumferential direction, but the outer ring in a free state. (2)
The overall shape of the outer ring (2) is curved in a non-circular state, and in the non-tightened state of the tightening bolts (4) and (4).
A frictional fastener configured such that the inner peripheral surface thereof partially contacts the outer peripheral surfaces of the pair of side rings (3) in the circumferential direction. 2. An outer ring (2) having a maximum diameter portion having a maximum diameter portion larger than an inner diameter of a corresponding boss (B) when the tightening bolts (4) and (4) are not tightened. 3. The friction fastener according to claim 1. 3. The frictional fastener according to claim 1, wherein the non-circular state of the outer race (2) is a flat circle or an ellipse. 4. A cutting slit (S) is formed in the outer ring (2) at one of a portion corresponding to the minor axis of a flat circle or an ellipse, and a maximum diameter portion of the tapered surface on both sides in the axial direction is formed. 4. The friction fastener according to claim 3, wherein the diameter at the minor diameter portion is set to be larger than the minimum diameter portion of the side rings. 5. The flat or elliptical circle is formed on the outer ring (2).
5. A flat circle or an ellipse having a portion set to a curvature (N ₁ ) larger than a curvature when the outer ring (2) is in a perfect circle state, according to claim 3 or 4. Friction fasteners. 6. The friction according to claim 5, wherein the outer ring (2) is bent to the large curvature (N ₁ ) over the entire circumference and is kept in a deformed state within an elastic limit. Fasteners.