JPH06193657A - One-way clutch - Google Patents

Abstract

PURPOSE:To prevent any indent in a contact part between a sprag and both inner and outer rings due to the load of over-torque from occurring, or this sprag from being subject to splitting loss otherwise, in a one-way clutch used with the sprag. CONSTITUTION:A sprag 7 is built in an interval between a cylindrical outer surface 2 of an inner ring 1 and a cylindrical inner surface 4 of an outer ring 3. A first circular surface 22 gradually increasing a wedge angle alpha and a second circular surface 23 to be formed in succession to the first circular surface 22 and suddenly increasing the wedge angle alpha both are formed in an inner diametral side cam surface 20 coming into contact with the cylindrical outer surface 2 of a sprag 7. In time of the load of over-torque, a slip is produced in space between the second circular surface 23 and the cylindrical outer surface 2 of the inner ring 1, thereby preventing any indent and a splitting loss in the sprag from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-way clutch using a sprag.

[0002]

2. Description of the Related Art FIG. 4 shows a sprag one-way clutch. This one-way clutch incorporates two cages 5 and 6 having different diameters between a cylindrical outer surface 2 of an inner ring 1 and a cylindrical inner surface 4 of an outer ring 3 and a plurality of pockets 5 in each cage 5 and 6.
a and 6a are formed, and the pockets 5a and 6 that face each other in the radial direction are formed.
A sprag 7 is incorporated in a, and an elastic member 8 for holding the sprag 7 at a position where the sprag 7 engages with the cylindrical outer surface 2 of the inner ring 1 and the cylindrical inner surface 4 of the outer ring 3 is provided between the cages 5 and 6. It is built in.

FIG. 5 shows the details of a sprag 7 which has been conventionally used normally. In the figure, the contact point between the inner ring 1 and the sprag 7 is A, and the contact point B between the outer ring 3 and the sprag 7 is
Then, the sprag height H is between A and B. On the other hand, the angle sandwiched by the straight line passing through the contact point A and extending from the rotation center O of the inner and outer rings 1 and 3 and the contact points A and B is the wedge angle α. The relationship between the sprag height H and the wedge angle α is shown in FIG.

In the case of the sprag 7, when the inner ring 1 rotates in the direction of the arrow in FIG. 5, the inner and outer cam surfaces 9, 10 incline to a position where torque is not transmitted, and the inner ring 1 and the outer ring 3 are allowed to rotate relative to each other. To do.

On the other hand, when the inner ring 1 is rotated in the direction opposite to the arrow, the cam surfaces 9 and 10 on the inside and outside of the sprag 7 are moved to the inner and outer rings 1, 3
To transmit the rotation of the inner ring 1 to the outer ring 3.

[0006]

By the way, in the sprag 7 in the conventional one-way clutch, the height H
Since the wedge angle α gradually increases as the torque increases, there is no problem when used below the rated torque, but when excessive torque is applied, the sprag 7 exceeds the predetermined torque transmission position and the inner and outer races 1 further. There is a problem in that an indentation is generated at a contact point between the sprag 7 and the inner and outer races 1 and 3 in an attempt to bite into the clutch 3, or the sprag 7 is broken to impair the clutch function.

The present invention solves the above-mentioned problems and prevents slippage at the contact point between the sprag and the inner ring to generate an indentation at the contact point or breakage of the sprag when an excessive torque is applied. To do this is a technical issue.

[0008]

In order to solve the above problems, according to the present invention, a cam surface on the inner diameter side that contacts the inner ring of the sprag has a first arc surface with a gradually increasing wedge angle, and The second arc surface is formed continuously from the first arc surface and has a sharply increased wedge angle.

Here, the first arc surface and the second arc surface may be provided on the cam surface on the outer diameter side of the sprag, or on both cam surfaces.

[0010]

As described above, according to the present invention, since the cam surface of the sprag is provided with the second arc surface whose wedge angle sharply increases, torque is transmitted between the inner ring and the outer ring through the sprag. In, when the excessive torque is applied, the second arc surface tries to contact the outer cylindrical surface of the inner ring or the inner cylindrical surface of the outer ring. At this time, since the second circular arc surface is a circular arc surface whose wedge angle rapidly increases, the second circular arc surface does not bite into the corresponding surface and slip occurs at the contact portion with the surface.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

The same parts as those of the one-way clutch shown in FIG. 5 described above are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 shows details of the sprag 7 incorporated between the inner ring 1 and the outer ring 3. The sprag 7 has cam surfaces 20 and 21 on the inner diameter side and the outer diameter side, respectively.

The cam surface 21 on the outer diameter side is formed by one arc surface having a radius of curvature Re centered on Oe. On the other hand, the cam surface 20 on the inner diameter side has a radius of curvature Ri centered on Oi _1.
A first arcuate surface 22 of the _1, is formed in the second arcuate surface 23 of the curvature radius Ri ₂ around the Oi _2, a first arcuate surface 22 and the second arcuate surface 23 is continuously There is.

As shown in the graph of FIG. 3, the first arc surface 22 has a wedge angle α as the sprag height H increases.
Is a radius of curvature that gradually increases. On the other hand, the second arc surface 23 has a radius of curvature at which the wedge angle α rapidly increases.

Here, as shown in FIG. 1, the sprag height H is a length between two contact points A and B at which the cam surfaces 20 and 21 inside and outside the sprag 7 and the inner and outer races 1 and 3 come into contact with each other. On the other hand, the wedge angle α passes through the contact point A, and the inner and outer rings 1,
The intersection angle of a straight line extending from the center O of 3 and a straight line connecting the contact points A and B.

FIG. 1 shows a state in which the cam surfaces 20 and 21 on the outer diameter side and the inner diameter side of the sprag 7 are in contact with the cylindrical outer surface 2 of the inner ring 1 and the cylindrical inner surface 4 of the outer ring 3. When the inner ring 1 rotates in the direction of the arrow in the figure from this state, the sprag 7
Rotates clockwise, and the height H of the sprag 7 gradually decreases. Therefore, the cam surface 2 on the inner and outer diameter sides of the sprag 7
As shown in FIG. 2A, 0 and 21 do not engage with the inner and outer races 1 and 3, and the inner race 1 idles with respect to the outer race 3.

On the other hand, when the inner ring 1 rotates in the direction opposite to the direction of the arrow in FIG. 1, the sprag 7 rotates counterclockwise and the height H of the sprag 7 increases, as shown in FIG. , The cam surface 21 on the outer diameter side of the sprag 7 is the cylindrical inner surface 4 of the outer ring 3.
And the first circular arc surface 2 on the cam surface 20 on the inner diameter side.
2 engages the cylindrical outer surface 2 of the inner ring 1. Due to the engagement, the rotation of the inner ring 1 is transmitted to the outer ring 3 via the sprag 7.

When the load acting on the outer ring 3 is increased, the sprag 7 further rotates in the same direction, and the contact point A ₁ with the inner ring 1 is an inflection point C from the first arc surface 22 to the second arc surface 23. Move towards.

When the inner ring 1 is rotated with a torque equal to or less than a predetermined set torque value, the sprag 7 engages with the cylindrical outer surface 2 of the inner ring 1 at one point on the first arc surface 22.
Is transmitted to the outer ring 3.

When an excessive torque exceeding the set torque value acts on the inner ring 1, the sprag 7 further rotates from the normal torque transmission position, the contact point of the inner ring 1 with the cylindrical outer surface 2 exceeds the inflection point C, and the second The arcuate surface 23 of is in contact with the cylindrical outer surface 2.

At this time, the wedge angle α of the second arc surface 23
Is gradually increased as the sprag height H increases,
There is a risk that the sprag 7 will further dig into the inner / outer rings 1 and 3 to generate indentations at the contact points between the sprag 7 and the inner / outer rings 1 and 3, or to break the sprag 7.

However, as described above, the wedge angle α of the second circular arc surface 23 sharply increases as the sprag height H increases, so that the second circular arc surface 23 is the cylindrical outer surface 2 of the inner ring 1. It does not bite into and slips between the sprag 7 and the cylindrical outer surface 2. Therefore, generation of indentations and breakage of the sprag 7 are prevented.

In the case of the embodiment, the cam surface 20 on the inner diameter side of the sprag 7 is provided with the first circular arc surface 22 and the second circular arc surface 23. It may be formed on the cam surface 21 on the outer diameter side, or on both cam surfaces 20, 21.

[0025]

As described above, in the one-way clutch according to the present invention, when excessive torque is applied to the inner ring, slippage occurs at the contact portion between the inner ring or the outer ring and the sprag, so that the sprag contacts the inner and outer rings. It is possible to prevent the occurrence of indentation in the portion or the breakage of the sprag.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part showing an embodiment of a one-way clutch according to the present invention.

[Fig. 2] (a) and (b) are cross-sectional views showing the operating state of the same as above.

FIG. 3 is a graph showing the relationship between sprag height and wedge angle.

FIG. 4 is a sectional view showing a conventional one-way clutch.

FIG. 5 is an enlarged view of the above sprag.

FIG. 6 is a graph showing the relationship between the sprag height and the wedge angle in the above.

[Explanation of symbols]

 1 inner ring 2 cylindrical outer surface 3 outer ring 4 cylindrical inner surface 5, 6 cage 5a, 6a pocket 7 sprag 8 elastic member 20, 21 cam surface 22 first circular arc surface 23 second circular arc surface

Claims (2)

[Claims] 1. Two cages having different diameters are provided between the cylindrical outer surface of the inner ring and the cylindrical inner surface of the outer ring, and one pocket of the outer ring and one of the inner ring are provided in the pockets of the respective cages which are opposed to each other in the radial direction. A cam that comes into contact with the inner ring of the sprag in a one-way clutch that incorporates a sprag that engages with both cylindrical surfaces by relative rotation in one direction and that includes an elastic member that holds the sprag in a position that engages with both cylindrical surfaces. A one-way surface provided with a first circular arc surface whose wedge angle gradually increases and a second circular arc surface which is formed continuously from the first circular arc surface and whose wedge angle sharply increases. clutch. 2. The one-way clutch according to claim 1, wherein the cam surface on the outer diameter side is provided with a first arc surface and a second arc surface instead of the cam surface on the inner diameter side of the sprag. A characteristic one-way clutch.