JP2002174271A - Cam for one-way clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a bearing pressure of a contact point of a cam for one-way clutch with a garter spring and facilitate its machining. SOLUTION: The cam 4 for one-way clutch consisting of an inner ring 1 and an outer ring 2, the cam 4 provided in a concentric circle space 3 between the inner and outer rings, and the (garter) spring 16 mounted in a central groove 5 of the cam is provided with a circular arc part 6 protruding on a side where the spring comes into contact with it, a bottom part 5a in the central groove of the cam is formed into a straight line, and the bottom part and the circular arc part are mutually connected by an obtuse angle or a tangential line. A position and an angle of the central groove are set in such a way that a depth of the central groove of the cam is set linearly on an inner side of the circle and the garter spring comes into contact with one circular arc point only at all times when forming the circle in which outer and inner raceway track center passing a circular arc contact point connected with a central groove of the spring is a radius when forming a strut angle of the cam. Furthermore, center of gravity G of the cam is set between a straight line 21 connecting the center O and a contact point A of the cam and the outer ring and a straight line 22 connecting a contact point B of the spring and the cam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A cam provided in a concentric space between an inner ring and an outer ring is radially urged by a spring force.
The present invention relates to a cam shape for a one-way clutch in which a contact length between an outer and inner ring and a cam is changed by tilting of the cam to transmit torque between the outer and inner rings in only one direction.

[0002]

2. Description of the Related Art There is a one-way clutch as a mechanism for extracting output torque with respect to input torque only in a predetermined one-way rotation. To achieve this function, a cam is provided in a concentric space between an inner ring serving as an input shaft and an outer ring serving as an output shaft. A structure is adopted in which the cam is disposed and a radial spring force is applied to the cam to forcibly set the outer and inner races and the installation point of the cam at the same radius instead of having the same radius, thereby allowing only one-way rotation. FIG. 3 shows the basic structure of such a known cam type one-way clutch in a torque transmitting state (when a strut angle is formed). As shown in FIG. 3, an inner ring 1 connected to an input shaft (not shown), an outer ring 2 connected to an output shaft (not shown),
A cam 1 is placed in a concentric space 3 formed by the inner ring 1 and the outer ring 2.
4 are provided. A substantially central portion in the longitudinal direction of the cam 14 is provided with a central groove 15, and a garter spring 16 is mounted in the central groove to urge the cam 14 toward the inner ring 1.

[0003] The cross-sectional shape of the cam 14 is such that almost half of the inner ring side forms a cylindrical part, and the outer ring side has a substantially triangular shape. When the cam fits in the space 3 of the outer and inner races, the contact point between the cylindrical side of the cam 14 and the raceway surface 1a of the inner race 1 is A, and the substantially triangular vertex of the cam 14 and the raceway of the outer race 2 Assuming that the contact point with the surface 2a is B, the length AB between the two contact points
Are set so that AB> length r in the radial direction of the inner and outer ring spaces. In addition, the distance from the inner ring side contact point A to the left side surface (longer diameter side surface) 14b of the vertex 14a is increased.
The right side surface (short diameter side surface) 14c of 4a is configured such that the distance from the inner ring side contact point A is smaller than the radial length r of the inner and outer wheel spaces. Therefore, the cam 14 does not fall to the right side any more in the figure. Further, straight lines OA and OB connecting the center O of the inner and outer rings and the respective contact points A and B are not arranged on the same line. On the other hand, the cam 14 easily rotates to the left as viewed in the figure, and the straight lines OA and OB connecting the contact points A and B are on the same line (the contact point A moves on the inner ring raceway surface). Furthermore, the outer ring and the cam do not come into contact with each other, and cannot function as a clutch.

Therefore, a center groove 15 is provided at the center in the longitudinal direction of the cam 14 so that the cam can contact the inner and outer rings, and an annular garter spring 16 is provided so as to contact the groove end 17 of the short diameter side surface 14c of the center groove. The cam is always urged in the clockwise direction by this contraction force. Thereby, inner ring 1
The cam 14 is urged in the clockwise direction by the garter spring even in the overrun where the right rotation with respect to the outer ring 2 is performed. It works as a one-way clutch. In the drawing, θi is a straddle angle.

[0005]

However, such a structure has a problem that the intersection between the groove end 17 and the outer periphery of the cam becomes an acute angle, so that an edge surface pressure is applied to the garter spring and the spring is cut off. Therefore, FIG.
As shown in the figure, the shape of the cam center groove is not straight, but is formed by two straight grooves 25 and 26 such that an obtuse angle is formed.
The garter spring always hit the intersection E of the two straight grooves. In this way, the contact pressure on the garter spring was reduced. Further, if the intersection point E is formed as a smooth circular arc as required, the effect of alleviating the surface pressure can be increased.

However, since these tools have a plurality of grooves, they cannot be machined unless a cutter or a workpiece can be moved two-dimensionally when machining a groove with a cutter. There was a problem of becoming. Also, processing time is required. Further, it was more difficult to work in an arc shape. SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to reduce surface pressure at a contact point between a garter spring and a cam, and to reduce cost by avoiding a dedicated machine for a processing machine.

[0007]

According to the present invention, there is provided an inner ring and an outer ring connected to respective shafts, a cam provided in a concentric space between the inner ring and the outer ring to transmit or cut off torque between the inner ring and the outer ring, A garter spring mounted in a central groove provided substantially at the center of the cam and biasing the cam toward the inner ring, a one-way clutch cam comprising:
The cam has an arc-shaped portion protruding on the outer periphery on the side where the garter spring contacts, and the center groove of the cam has a straight bottom portion, and the bottom portion and the arc-shaped portion are connected at an obtuse angle or a tangent line. The above object has been attained by providing a cam for a one-way clutch, which is characterized in that:

That is, since a protruding arc-shaped portion is provided on the outer periphery of the cam and the bottom of the central groove connected to the arc-shaped portion at an obtuse angle or a tangent line is straightened, the center groove is machined by one straight line. Only with this, it is possible to easily obtain the same shape as the conventional double linear groove or the conventional double linear groove and arcuate groove. The arc-shaped portion having a protruding cross section can be easily obtained by drawing or the like.

[0009] More preferably, when forming a strut angle of the cam, a cam center groove is formed when a circle having a radius at the center of the outer inner raceway passing through a contact point of an arc-shaped portion connected to the center groove of the spring is drawn. Is set linearly inside the circle so that the garter spring can always contact only one point of the circular arc provided at the cam end in both the state of forming the strut angle of the cam and the state of overrun. The central groove position and angle are set,
The center of gravity of the cross section of the cam may be located between a straight line connecting the cam and the contact point between the outer ring and a straight line connecting the contact point between the garter spring and the cam.

A better contact surface pressure can be obtained by contacting the garter spring with the arc-shaped outer peripheral portion protruding from the cam cross section. Further, when changing the cross-sectional shape of the cam, by setting the shape so that the centroid G is located between the contact point B between the outer ring and the cam and the contact point E between the garter spring and the cam, the present invention can be applied to the death engage type.

[0011]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially enlarged cross-sectional view showing the vicinity of a cam in a torque transmitting state (at the time of strut angle formation) of a cam type one-way clutch showing an embodiment of the present invention, and FIG. 2 shows the vicinity of a cam in an overrun state. It is a partial expanded sectional view. In FIG. 1, an inner ring 1 connected to an input shaft (not shown), an outer ring 2 connected to an output shaft (not shown), and a concentric space 3 formed by the inner ring 1 and the outer ring 2 include:
The cam 4 of the present invention is provided. The cross section of the cam 4 has an arc-shaped portion 6 protruding from the outer periphery on the side (the right side in the figure) where the garter spring contacts, and a central groove 5 having a straight bottom at the center in the longitudinal direction of the cam is formed. The central groove (bottom) 5 and the arc-shaped portion 6 are connected so as to be tangent.

A substantially half 4c of the section of the cam 4 on the inner ring side forms a cylindrical part, and the outer ring side has a triangular shape with approximately equal sides. When the cam fits in the space 3 of the outer and inner races, the contact point between the cylindrical side of the cam 4 and the raceway surface 1a of the inner race 1 is A, and the apex of the substantially equilateral triangle of the cam 4 and the outer race 2 Assuming that a contact point with the raceway surface 2a is B, the length A between the two contact points is
B is set to be longer than the radial length r of the inner and outer ring spaces. Also, the left side surface of the vertex 4a (the side surface of the anti-arc portion 6) 4
b, the distance from the inner ring side contact point A is increased, and the right side surface (arc side surface) 4c of the vertex 4a is the inner ring side contact point A.
Is smaller than the radial length r of the inner and outer ring spaces. Therefore, the cam 4 does not fall to the right side any more in the figure.

An annular garter spring 16 is fitted so as to be in contact with the outer periphery 6a of the arcuate portion 6 of the cam 4, and the contraction force urges the cam 4 in the radial direction, thereby rotating the cam 4 in the clockwise direction. It is always energized. In addition, when a strut angle of the cam 4 shown in FIG. 1 is formed, when a circle having the radius of the center of the outer and inner raceway passing through the contact point E of the spring 16 is drawn, the depth of the cam center groove 5 is linearly arranged inside the circle. The position and angle of the central groove 5 are set so that the garter spring 16 can always contact only the arcuate portion 6 in both the strut angle formation of the cam 4 and the overrun shown in FIG. I have.
Further, the center of gravity G of the cross section of the cam 4 has a straight line 21 connecting the cam 4 and the contact point B between the outer ring 2 and the garter spring 16.
And a straight line 22 connecting a contact point E between the cam 4 and the upper part 6 of the circular arc.

As a result, the cam 4 is urged in the clockwise direction by the garter spring 16 even during an overrun in which the inner race 1 rotates clockwise with respect to the outer race 2 as shown in FIG. The outer rings are brought into contact with each other to connect the inner and outer rings to each other so that torque can be transmitted. Although the above-mentioned arc-shaped portion has the same shape in the longitudinal direction in consideration of the drawing process, it goes without saying that it may be formed only near the central groove.

[0015]

According to the present invention, an arcuate portion is provided on the outer periphery of the cam and the bottom of the central groove connected to the arcuate portion at an obtuse angle or a tangential line is straightened. Surface pressure can be alleviated, processing can be easily performed, and the cost can be reduced without using a dedicated machine. In addition, since the projections are formed in an arc shape, the directions can be easily identified at the time of assembly, and effects such as easy work can be obtained.

If the arc-shaped outer peripheral portion is brought into contact with the garter spring, the contact surface pressure becomes lower and a long life can be expected.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view showing the vicinity of a cam in a torque transmitting state (at the time of strut angle formation) of a cam type one-way clutch according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing the vicinity of a cam in an overrun state of a cam type one-way clutch according to an embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view showing the vicinity of a cam in a torque transmission state of a conventional cam type one-way clutch.

FIG. 4 is a partially enlarged cross-sectional view showing the vicinity of a cam in a torque transmission state of another conventional cam type one-way clutch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Concentric circle space 4 Cam 5 Center groove 5a Bottom 6 Arc-shaped part 16 Garter spring, 21 Straight line connecting the contact point of cam and outer ring 22 Straight line connecting the contact point of garter spring and cam A Cam and outer ring Point of contact B with garter spring and cam E point of contact G center of gravity

Claims (2)

[Claims] An inner ring and an outer ring connected to respective shafts, a cam provided in a concentric space between the inner ring and the outer ring to transmit or cut off torque between the inner ring and the outer ring, and provided substantially at the center of the cam. A garter spring that is mounted in a central groove and biases the cam toward the inner ring side, the cam for a one-way clutch, wherein the cam has an arc-shaped portion protruding on the outer periphery on the side where the garter spring contacts, A cam for a one-way clutch, wherein a bottom portion of the central groove of the cam is straightened, and the bottom portion and the arc-shaped portion are connected at an obtuse angle or a tangent line. 2. The depth of the cam center groove when a circle having a radius of the center of the outer ring raceway passing through the contact point of the arc-shaped portion connected to the center groove of the spring when forming the strut angle of the cam is drawn. The central groove position and angle are set so that the garter spring can always contact only the one point of the circular arc provided at the cam end, and the cross section of the cam The center of gravity of the garter spring is located between a straight line connecting the contact point between the cam and the outer ring and a straight line connecting the contact point between the garter spring and the cam. The one-way clutch cam described.