JP2000274456A - One-way clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure excellent engagement and transmission torque capacity higher than a given level regardless of a machining error of a cam surface. SOLUTION: A one-way clutch 10 performs synchronous rotation or relative rotation of two annulus bodies 11 and 12 of one being an inner annulus body and the other outer annulus body being concentrically disposed. Cam surfaces 16 formed in a wedge-form space wherein an opposite distance between the outer peripheral surface of an inner ring 12 and the inner peripheral surface of an outer ring 11 is decreased in one direction of a peripheral direction are formed in a plurality of spots of a periphery and the cam surface 16 is formed in a partially arcuate shape. This constitution reduces a change amount of the wedge angle of the wedge-form space even when a machining error occurs to the cam surface 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a one-way clutch. In particular, the cam surface of the one-way clutch has been improved.

[0002]

2. Description of the Related Art Conventionally, as a one-way clutch, a type using rollers has been generally known. In this type of one-way clutch, rollers are circumferentially rollably interposed in wedge-shaped spaces provided at several places on the circumference between an outer ring and an inner ring that are concentrically arranged inside and outside the radial direction. This wedge-shaped space is one in which the radially opposed interval between the outer ring and the inner ring is narrowed toward one side in the circumferential direction, and by forming cam surfaces at several places around the inner peripheral surface of the outer ring or the outer peripheral surface of the inner ring. Provided.

[0003] The applicant of the present invention provides the above-described cam surface on the outer peripheral surface of the inner race as a structure suitable for use at high speed rotation. The cam surface has a flat shape in consideration of workability.

FIG. 10 shows a conventional one-way clutch as described above. In the figure, 80 is the whole one-way clutch, 81
Is an outer ring, 82 is an inner ring, 83 is a plurality of rollers, 84 is a cage, 85 is a plurality of coil springs, and 86 is a cam surface.

The transmission torque capacity and the engagement when the cam surface 86 is flat will be described with reference to FIG. In the figure, T is the transmission torque capacity, θ is the wedge angle, n is the number of rollers 83, R is the inner diameter of the outer ring 11 (radius of the outer ring raceway), N ₁ and N ₂ are normal loads, and F ₁ and F ₂ are tangents. It is a load.

[0006] The transmission torque capacity T is obtained by a formula of T = nF ₁ R. F ₁ is N ₁ tan θ / 2, and when substituted into the above-mentioned formula, T = n (N ₁ tan θ / 2) R
Becomes From this equation, it can be said that the larger the wedge angle θ, the greater the transmission torque capacity T.

[0007] Further, the locked state for transmitting torque is as follows.
μN ₁ > N ₁ tan θ / 2, that is, μ> tan θ / 2. Here, μ is a coefficient of friction. From this calculation formula, it can be said that if the wedge angle θ is large, μ <tan θ / 2, and the rollers 83 become slippery. On the other hand, if the wedge angle θ is too small, the rollers 83 may not be able to return from the locked state to the free state.

[0008]

When the cam surface 86 has a flat shape as in the prior art, the radial position of the cam surface 86 is indicated by _R0 in FIG. 12 due to a processing error. If variation with respect to the position (designed to required position) even slightly R ₁ position and R ₂ position in FIG. 12,
Since the width of change increases when the wedge angle increases from θR ₀ to θR ₁ or decreases as indicated by θR ₂ , it can be said that the behavior of the rollers 83 tends to be unstable. In FIG. 12, the processing error is exaggerated.

[0009] Incidentally, in FIG. 12, with respect to the wedge angle .theta.R ₀ by design requirements, becomes as large indicated by .theta.R _1, roller 83 is such engagement worsens slippery, and in .theta.R ₂ As shown,
The transmission torque capacity in the locked state tends to decrease.

As described above, in the case of the above-described conventional one-way clutch 80, in order to improve the meshing operation and to increase the transmission torque capacity in the meshed state (locked state), a flat cam is required. It is necessary to control the wedge angle of the wedge-shaped space formed by the surface 86 with high precision,
It is pointed out that it is extremely troublesome.

In view of such circumstances, an object of the present invention is to provide a one-way clutch capable of ensuring good engagement and a transmission torque capacity of a required level or more irrespective of a machining error of a cam surface. I have.

[0012]

A one-way clutch according to the first aspect of the present invention is provided such that two-way clutches are concentrically disposed radially inward and outward.
The two rings are rotated synchronously or relative to each other, and at several places on the outer surface of the inner ring, the distance between the outer ring and the inner surface is narrower in the circumferential direction. A cam surface for forming a space is provided, and the cam surface is formed so as to bulge radially outward in a partial arc shape.

The one-way clutch according to the second aspect of the present invention synchronously rotates or relatively rotates two concentric rings arranged radially inward and outward. A cam surface for forming a wedge-shaped space which is provided at several places around the circumference and narrows an opposing interval with the inner peripheral surface of the outer annular body toward one side in the circumferential direction, and is integrally fitted to the inner annular body. And a cage having pockets penetrating inward and outward in the radial direction in regions corresponding to the plurality of cam surfaces, a plurality of rollers accommodated in the pockets of the cage so as to be rollable in the circumferential direction, and pockets of the cage, respectively. And a pressing member which is housed adjacent to the roller in the circumferential direction and presses the roller toward the narrow side of the wedge-shaped space, wherein the cam surface is formed to protrude radially outward in a partial arc shape.

A one-way clutch according to a third aspect of the present invention is for rotating or rotating two concentrically arranged annular members radially inward and outward. Convex walls protruding radially outward from the center of rotation are provided at several places around the circumference, and the bottom surface of each concave pocket present in the region between the convex walls is opposed to the outer ring body. A cam surface is provided for forming a wedge-shaped space in which the interval is narrowed toward one side in the circumferential direction.A roller and a pressing member for pressing the roller toward the narrow side of the wedge-shaped space are provided in each of the concave pockets. Are arranged and arranged adjacent to each other in the circumferential direction, and the cam surface is formed so as to bulge radially outward in a partial arc shape.

According to a fourth aspect of the present invention, in the one-way clutch, the radius of curvature (R1) of the cam surface according to any one of the first to third aspects is determined by calculating the diameter of the roller from the inner peripheral surface radius (R) of the outer ring. (R1) is set to a numerical value obtained by subtraction.

As described above, in the present invention, the cam surface formed on the outer peripheral surface of the inner ring is formed in a partial arc shape. In this case, even if there is a processing error in the cam surface, the wedge angle of the wedge-shaped space does not change significantly.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on embodiments shown in the drawings.

FIGS. 1 to 6 show an embodiment of the present invention. FIG. 1 is a longitudinal front view of a one-way clutch, and FIG.
Is a developed plan view showing the retainer and the rollers housed therein,
FIG. 3 is a front view of the one-way clutch, FIG. 4 is a perspective view showing the inner race, FIG. 5 is a diagram used to explain a calculation formula of a transmission torque capacity of the one-way clutch, and FIG. It is explanatory drawing which shows the change of the wedge angle of the wedge-shaped space related to a processing error.

In the drawing, reference numeral 10 denotes the whole one-way clutch. The one-way clutch 10 includes an outer race 11, an inner race 12, a plurality of rollers 13, a retainer 14, and a plurality of coil springs 15, and has basically the same configuration as the conventional example.

The outer race 11 and the inner race 12 are arranged concentrically inside and outside in the radial direction. Of these, a cam surface 16 for forming a wedge-shaped space for reducing the facing distance between the outer ring 11 and the outer ring 11 toward one side in the circumferential direction is formed at several places on the outer peripheral surface of the inner ring 12.
Is provided on one side in the circumferential direction of the cam surface 16.
The receiving seat 17 of the coil spring 15 is formed adjacently. The receiving seat 17 is formed flat to keep the posture of the coil spring 15 stable.

The plurality of rollers 13 are arranged so as to be able to roll in the circumferential direction in a wedge-shaped space formed between the cam surface 16 and the inner peripheral surface of the outer ring 11.

The retainer 14 is externally fitted to a cylindrical portion that is partially left in the circumferential direction on the outer peripheral surface of the inner ring 12,
In a region corresponding to each cam surface 16 and flat surface 17 of the inner race 12, there is provided a pocket 14a penetrating in and out in the radial direction and accommodating a plurality of rollers 13 individually. The retainer 14 is fixed to the inner ring 12 by fitting a protrusion 14 b provided at one end in the axial direction to a slit-shaped recess 12 a provided in the inner ring 12.

A plurality of coil springs 15
Are stored in a compressed state in a state adjacent to the roller 13 in the circumferential direction in each pocket 14a. Each of these coil springs 15 presses each roller 13 toward the narrow side of the wedge-shaped space by the extension restoring force. In particular, in this embodiment, as the above-described coil spring 15,
In order to avoid the skew of No. 3, by using an elliptical shape as viewed from the end face, the roller 13 is applied to a region as wide as possible in the axial direction.

Next, the operation of the one-way clutch 10 will be described.

First, when the outer ring 11 is driven to rotate in only one direction and the inner ring 12 is driven, when the rotation speed of the outer ring 11 is increased, the rollers 13 rotate to the narrow side of the wedge-shaped space. Since the inner ring 12 is moved and bites between the outer ring 11 and the inner ring 12, the inner ring 12 is integrated with the outer ring 11 and rotates synchronously. This state is a locked state.

However, when the rotation speed of the inner race 12 becomes higher than that of the outer race 11 due to a decrease in the rotation speed of the outer race 11, the rollers 13 move to the wide side of the wedge-shaped space against the spring force of the coil spring 14. The outer ring 11 and the inner ring 1
2 will rotate relative to each other. This state is a free state.

When the outer ring 11 is used in such a manner as to be arbitrarily rotated in both directions, when the outer ring 11 rotates counterclockwise in FIG. However, when the outer ring 11 rotates clockwise in FIG. 1, the outer ring 11 enters the free state as described above and moves from the outer ring 11 to the inner ring 1.
2, the rotation power is not transmitted, and only the outer ring 11 rotates, and the inner ring 12 does not rotate.

The one-way clutch 10 of this embodiment is characterized in that the cam surface 16 provided on the inner race 12 is not a flat shape as in the conventional example but a partial arc shape. In particular, in this embodiment, the cam surface 16 is provided with a concave portion at several places on the circumference of the inner ring 12, and formed on the bottom surface of the concave portion so as to bulge radially outward in a partial arc shape.

As described above, the cam surface 16 provided on the inner race 12
Will be described with reference to FIG. 5 in terms of the transmission torque capacity and the meshing property in the case of forming a partial arc.

In the figure, T is the transmission torque capacity, θ is the wedge angle, α is の of the wedge angle θ, n is the number of rollers 13, r
The radius of the roller 13, R 1 is the radius of curvature of the cam surface 16, L is the effective length of the roller 13, R is the inner diameter of the outer race 11 (the outer raceway radius), and F is the tangential load.

The transmission torque capacity T is obtained by a formula of T = nFR. F is a calculation formula of Hertz stress, that is, (σ
max / 0.418) ² rR1 / (r + R1) L / Et
anα, and when this equation is substituted into the above equation, T = n (σmax / 0.418) ² rR1 / (r +
R1) L / EtanαR. From this equation, it can be said that the larger the wedge angle θ, the greater the transmission torque capacity T.

The numerical value "0.418" in the above equation is used.
Is P ² = 1 / π (r + R1 / rR1) · q / Q ｛(1
−ν1 / E1) + (1−ν1 / E2)}. Here, the rollers 13, the outer ring 11 and the inner ring 12
Are steel materials, their Young's modulus is E1 = E2
= E, and the Poisson's ratio is ν1 = ν2 = 0.3.
By substituting this value into the above formula, "0.418" is obtained.
Is obtained.

The locked state in which the torque can be transmitted is a state where μN> Ntan θ / 2. Here, μ is a coefficient of friction. From this calculation formula, it can be said that if the wedge angle θ is large, μ <tan θ / 2, and the rollers 13 become slippery. Therefore, it can be said that the smaller the wedge angle θ, the better the meshing property. However, if the wedge angle θ is too small, the rollers 13 may not return from the locked state to the free state.

It is preferable that the radius of curvature R1 of the cam surface 16 having the partial arc shape as described above is set to a value obtained by a calculation formula of R1 = R-r1. R is the outer ring 11
, R1 is the diameter of the roller 13.

As shown in FIG. 6, a straight line connecting the center of curvature O ₂ of the cam surface 16 and the center O ₃ of the center 13 connects the center O ₁ of the inner ring 12 and the center of the outer ring 11 with the center O _3. Although it is inclined with respect to the straight line, the inclination angle is set to be substantially the same as the wedge angle θ required in design.

By the way, if the shape of the cam surface 16 is formed in a partially arcuate shape as described above, the position of the cam surface 16 in the radial direction may be changed to the position indicated by R ₀ in FIG. 6 does not change so much as shown in θR ₁ and θR ₂ with respect to the wedge angle θR ₀ required in design, even if it is shifted to the R ₁ position or R ₂ position in FIG. Therefore, it can be said that the behavior of the rollers 13 is kept stable. In FIG. 6, the processing error is exaggerated. By the way, when the variation of the processing error of the cam surface 16 and the rollers 13 is 0.2 mm, the variation of the wedge angle θ is ± 0.005 degrees, and there is no need to change much.

As described above, in the one-way clutch 10 according to the present embodiment, the amount of change in the wedge angle θ can be reduced even if there is a processing error in the cam surface 16.
Even if you do not manage the processing accuracy of high precision as in the conventional example,
A structure that demonstrates an excellent clutch function can be achieved.

It should be noted that the present invention is not limited to the above embodiment, and various applications and modifications are conceivable.

(1) In the above embodiment, for example, as shown in FIG. 7, the receiving surface 17 of the coil spring 15 may be omitted and only the cam surface 16 may be formed. In that case, processing becomes simple.

(2) Although the retainer 14 is used in the above embodiment, a structure in which the retainer 14 is omitted, for example, the structure shown in FIG. 8 is also included in the present invention. The one-way clutch 10 shown in FIG. 8 has a structure in which the retainer 14 is formed integrally with the inner ring 12. Specifically, at several locations on the outer circumferential surface of the inner ring 12, convex wall portions 12 b protruding radially outward are provided, and a concave pocket 12 c is provided in a region between the convex wall portions 12 b. Each is present, the bottom of each concave pocket 12c,
A cam surface 16 is provided to form a wedge-shaped space that narrows the facing distance between the outer ring 11 and the outer ring 11 in one circumferential direction. A plurality of rollers 13 and a plurality of coil springs 15 are housed and arranged in the concave pocket 12c of the inner race 12 so as to be adjacent to each other in the circumferential direction. In order to prevent the coil spring 15 from coming out of the inner pocket 12 radially outward from the concave pocket 12c, the retaining cover 18 is attached to the inner race 12.
Is fitted to the outside. The retaining cover 18 is formed of an annular body in which protruding pieces are arranged in a comb-teeth shape at several places around the circumference.

By the way, the one-way clutch 10 in the above embodiment can be built in pulleys of various auxiliary machines mounted on an engine such as an automobile. Specifically,
FIG. 9 shows an example in which the one-way clutch 10 is incorporated in a pulley of an alternator as an auxiliary device of an automobile.

In the illustrated pulley unit A, a one-way clutch 10 is disposed in a region between the two rolling bearings 3 and 3 in an annular space between the pulley 1 and the rotating shaft 2. In this example, the pulley 1 also serves as the outer ring 11 of the one-way clutch 10, and the inner ring 12 of the one-way clutch 10
Are fitted to the rotating shaft 2 by press fitting.

The pulley unit A is used in such a form that the pulley 1 is rotated only in one direction and the rotation speed is arbitrarily changed. The operation is the same as the operation of the one-way clutch 10 described above.

That is, when the pulley 1 is rotated in the required direction by the belt B, the one-way clutch 10 is locked as the rotation rises, and the rotational power from the pulley 1 to the inner ring 12 and the rotating shaft 2 is substantially reduced. It is transmitted at a ratio of 1: 1.

However, assuming that the rotation of the pulley 1 is rising,
When the rotation speed of the pulley 1 temporarily decreases, the rotation speed of the inner ring 12 and the rotating shaft 2 becomes momentarily faster than the rotation speed of the pulley 1 due to the rotational inertia force.
Is in a free state, and transmission of rotational power from the pulley 1 to the rotary shaft 2 is interrupted.

Thereafter, when the rotational speed of the pulley 1 becomes higher than that of the rotary shaft 2 again, the one-way clutch 10 is again locked, so that rotational power is transmitted from the pulley 1 to the rotary shaft 2. Become.

As described above, even if the rotational speed of the pulley 1 fluctuates (pulsates), the one-way clutch 10 switches between the locked state and the free state as appropriate, and the rotational speed of the pulley 1 pulsates. Is rectified and transmitted to the rotating shaft 2 linearly. In addition, even when the rotation speed of the pulley 1 is reduced, the one-way clutch 10 is in a free state, and the rotating shaft 2 can be rotated at a high speed by its own rotational inertia force. Can be.

[0048]

According to the first to third aspects of the present invention, the amount of change in the wedge angle can be reduced even if there is a processing error in the cam surface, so that the processing accuracy of the cam surface is not controlled with high accuracy as in the conventional example. In both cases, a structure capable of exhibiting an excellent clutch function can be obtained. Therefore, according to the present invention, it is possible to provide a one-way clutch which is excellent in productivity and highly functionally reliable.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of an upper half of a one-way clutch according to an embodiment of the present invention.

FIG. 2 is an exploded plan view showing the cage and the rollers housed in FIG. 1;

FIG. 3 is a front view of the upper half of the one-way clutch shown in FIG. 1;

FIG. 4 is a perspective view of the retainer in FIG. 1;

FIG. 5 is a diagram used to explain a calculation formula of a transmission torque capacity of the one-way clutch in FIG. 1;

FIG. 6 is an explanatory diagram showing a change in a wedge angle of a wedge-shaped space related to a machining error of a cam surface.

FIG. 7 is a longitudinal sectional front view corresponding to FIG. 1 according to another embodiment of the present invention.

FIG. 8 is a longitudinal sectional front view corresponding to FIG. 1 according to another embodiment of the present invention.

FIG. 9 is a longitudinal sectional side view of a pulley unit incorporating a one-way clutch according to the embodiment.

FIG. 10 is a longitudinal sectional front view of a conventional one-way clutch.

11 is a diagram used to explain a calculation formula of a transmission torque capacity of the one-way clutch in FIG. 10;

FIG. 12 is an enlarged view of a main part showing a malfunction of the one-way clutch in FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 One-way clutch 11 Outer ring 12 Inner ring 13 Roller 14 Cage 14a Cage pocket 15 Coil spring 16 Inner ring cam surface

Claims (4)

[Claims] 1. A one-way clutch for synchronously rotating or relatively rotating two rings disposed concentrically inside and outside a radial direction, wherein the outer ring is provided at several places on the outer peripheral surface of the inner ring. A cam surface is provided for forming a wedge-shaped space in which the distance between the inner surface of the ring and the inner peripheral surface is narrowed toward one side in the circumferential direction, and the cam surface protrudes radially outward in a partial arc shape. A one-way clutch, characterized in that: 2. A one-way clutch for synchronously rotating or relatively rotating two rings disposed concentrically inside and outside a radial direction, provided at several places on the outer peripheral surface of an inner ring. A cam surface for forming a wedge-shaped space in which the distance between the inner peripheral surface of the outer ring body and the inner peripheral surface is reduced in one of the circumferential directions; and A cage having a pocket penetrating in and out in the radial direction in a corresponding region; a plurality of rollers housed in each of the pockets of the cage so as to be able to roll in the circumferential direction; A pressing member that is housed next to each other and presses the rollers toward the narrow side of the wedge-shaped space, wherein the cam surface is formed to protrude radially outward in a partial arc shape. Direction clutch. 3. A one-way clutch for synchronously rotating or relative rotating two concentric rings disposed radially in and out, wherein the inner ring has a plurality of rotations at several circumferential positions on an outer peripheral surface thereof. A convex wall portion radially outwardly protruding from the center is provided, and at the bottom surface of each concave pocket present in a region between the convex wall portions, the facing interval with the outer ring body is set to one circumferential direction. A cam surface for forming a wedge-shaped space that is narrowed toward is provided.In each of the concave pockets, a roller and a pressing member that presses the roller toward the narrow side of the wedge-shaped space are circumferentially adjacent to each other. A one-way clutch, wherein the one-way clutch is housed and arranged, and the cam surface has a shape protruding radially outward in a partial arc shape. 4. The one-way clutch according to claim 1, wherein the radius of curvature (R1) of the cam surface is obtained by subtracting the diameter of the roller (r1) from the radius of the inner peripheral surface (R) of the outer ring body. A one-way clutch, characterized in that the one-way clutch is set to a value determined by the following.