JP2016118280A - Ribbon spring for sprag type one-way clutch, and sprag type one-way clutch including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change a spring load energizing a sprag while maintaining an eigen frequency of a leaf spring part, without changing a main dimension of the leaf spring part, in a ribbon spring for a sprag type one-way clutch.SOLUTION: A leaf spring part 30 of a ribbon spring 13 has a narrow width part 31 formed between a bridge part 21 and the tip of the leaf spring part 30 in a circumferential direction. The narrow width part 31 has an effective length in an axial direction smaller than the effective length of the leaf spring part 30 other than the narrow width part 31 in the circumferential direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a ribbon spring for energizing a sprag in a sprag type one-way clutch (hereinafter referred to as a one-way clutch) used in a power transmission device such as an automatic transmission of an automobile.

  In an automatic transmission of an automobile, a one-way clutch is known that is disposed between an inner ring and an outer ring and repeatedly performs power transmission and interruption (Patent Document 1). As shown in FIG. 6, the one-way clutch 100 includes a sprag 101, a cage 102, and a ribbon spring 103, and is disposed in an annular space that is sandwiched between the outer ring 104 and the inner ring 105 in the radial direction. The one-way clutch 100 performs transmission and interruption of power by the sprag 101 being engaged when the outer ring 104 and the inner ring 105 rotate relative to each other. In FIG. 6, when the outer ring 104 rotates clockwise, the sprag 101 is engaged (hereinafter referred to as “lock”), and the outer ring 104 and inner ring 105 rotate together, and when the outer ring 104 rotates counterclockwise. Since the engagement of the sprag 101 is released, the outer ring 104 idles and power transmission is interrupted.

In the one-way clutch 100, the ribbon spring 103 is guided on the inner diameter side of the cage 102, and the leaf spring portion 106 that is a part of the ribbon spring 103 biases the sprag 101 in a direction in which the sprag 101 is engaged with the inner and outer rings 104 and 105. doing. The leaf spring portion 106 extends in a tongue shape from the bridging portion 107 of the ribbon spring 103 in the circumferential direction, and urges the sprag 101 by elasticity when the tip of the leaf spring portion 106 is bent in the radial direction. A force F by which the leaf spring portion 106 biases the sprag 101 is indicated by an arrow in FIG. When the force F is strong, the slip resistance between the sprag 101 and the inner ring 105 increases when the outer ring 104 idles, so that the idling torque increases and power loss occurs, or the raceway surface of the inner ring 105 wears out. A malfunction occurs.
Therefore, in order to reliably operate the one-way clutch 100, it is necessary to appropriately set the force for urging the sprag 101 of the leaf spring portion 106.

JP 2003-130089 A

  In order to set the spring force, the length and the plate thickness of the leaf spring portion 106 are generally changed. However, when the length or thickness of the leaf spring portion 106 is changed, the natural frequency at which the leaf spring portion 106 bends in the radial direction changes. When the natural frequency matches the frequency generated by the vehicle, the leaf spring portion 106 resonates. When resonance occurs, the leaf spring portion 106 is damaged and the one-way clutch 100 does not operate. Therefore, even when the spring force of the leaf spring portion 106 is changed, it is not preferable to change the natural frequency.

  An object of the present invention is to provide a sprag type one-way clutch ribbon spring that biases the sprag while maintaining the natural frequency of the leaf spring without changing the main dimension of the leaf spring of the ribbon spring. It is to change the load.

  A ribbon spring according to an embodiment of the present invention includes a pair of annular portions facing each other on both sides in the axial direction, and a circumferentially spaced interval between the pair of annular portions, and defines a window hole between the circumferential directions. A plurality of bridging portions and a leaf spring portion extending in the circumferential direction from one circumferential side surface of the bridging portion toward the window hole, and a sprag biased by the leaf spring portion to the window hole. In the sprag type one-way clutch ribbon spring to be inserted, the leaf spring portion is formed with a narrow width portion between the bridging portion and a tip of the leaf spring portion in the circumferential direction. The portion has an effective length in the axial direction smaller than an effective length of the leaf spring portion other than the narrow width portion in the circumferential direction.

  According to the present invention, in the spring spring for a sprag type one-way clutch, the spring load that biases the sprag while maintaining the natural frequency of the leaf spring without changing the main dimension of the leaf spring of the ribbon spring. Can be changed.

It is a side view of the one-way clutch which is 1st Embodiment of this invention. Fig.2 (a) is a front view of the ribbon spring of 1st Embodiment, FIG.2 (b) is a fragmentary sectional view in XX of Fig.2 (a). FIG. 3 is an enlarged view of a main part of FIG. FIG. 4 (a) is a diagram schematically showing the difference in shape of the leaf spring portion, FIG. 4 (b) is a conceptual diagram showing a spring system of the leaf spring portion, and FIG. FIG. 4D is a diagram showing the relationship between the shape and the natural frequency, and FIG. 4D is a diagram showing the relationship between each shape and the spring constant. It is a principal part enlarged view of the ribbon spring of 2nd Embodiment. It is a figure which shows the structure of the conventional one-way clutch.

  A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partial side view of a one-way clutch 10 according to a first embodiment of the present invention. Although only a part is shown, the configuration of the part not shown is the same, and is connected in an annular shape as a whole. In the following description with reference to FIG. 1, the vertical direction in the figure is referred to as the radial direction, and the left and right directions are referred to as the circumferential direction. The direction perpendicular to the paper surface is called the axial direction.

  The one-way clutch 10 includes a plurality of sprags 11, a retainer 12, and a ribbon spring 13, and is incorporated in an annular space formed between the inner ring 14 and the outer ring 15.

  The sprags 11 are made of metal and are arranged at equal intervals in the circumferential direction. The sprag 11 has an arc-shaped outer ring engagement surface 16 that protrudes upward in the radial direction, and an arc-shaped inner ring engagement surface 17 that protrudes downward in the radial direction. One side surface (the left side surface of the sprag 11 in FIG. 1) of the pair of side surfaces that are formed on both sides of the sprag 11 in the circumferential direction and connect the outer ring engagement surface 16 and the inner ring engagement surface 17 in the radial direction. Is formed with a spring receiving portion 19 that engages with the leaf spring portion 30 of the ribbon spring 13.

  The cage 12 has a substantially cylindrical shape and is made of metal or reinforced resin. A plurality of pockets 18 penetrating in the radial direction are provided on the circumferential surface of the cage 12 at equal intervals in the circumferential direction. The pocket 18 has a substantially rectangular shape when viewed from the radial direction, and one sprag 11 is fitted in each pocket 18.

The shape of the ribbon spring 13 will be described with reference to FIG. FIG. 2A is a front view of the ribbon spring 13 in a free state before being incorporated into the one-way clutch 10. FIG. 2B is a partial cross-sectional view of the ribbon spring 13 when the XX cross section is viewed from below.
The ribbon spring 13 is formed into a ribbon shape by pressing a rolled steel strip for spring. When incorporated in the one-way clutch 10, both ends of the ribbon spring 13 are bent in the direction perpendicular to the paper surface and rounded so that both ends overlap. Thereafter, the ribbon spring 13 is incorporated along the inner periphery of the cage 12. Therefore, in the description with reference to FIG. 2, the longitudinal direction of the ribbon spring 13 (the left-right direction in the figure) is referred to as the circumferential direction, and the direction orthogonal to the circumferential direction is referred to as the axial direction. Also, the near side in the direction perpendicular to the paper surface is referred to as the outer circumferential direction, and the inner side is referred to as the inner circumferential direction.

The ribbon spring 13 has a pair of annular portions 20 and 20 extending in parallel with each other in the circumferential direction, and a plurality of bridging portions 21 that connect the annular portions 20 and 20 in the axial direction at a predetermined interval. . The bridging portion 21 is provided with a hole 22 for weight reduction.
A leaf spring portion 30 is provided at a substantially central portion in the axial direction of the bridging portion 21. The leaf spring portion 30 extends in the circumferential direction from one side surface 21 a in the circumferential direction of the bridging portion 21 toward the adjacent bridging portion 21. The detailed shape of the leaf spring portion 30 will be described later.
Thus, the ribbon spring 13 has a window hole 23 that is defined in the axial direction by the pair of annular portions 20, 20 and that is defined in the circumferential direction by the adjacent bridging portion 21 to have a substantially U-shape. A plurality of layers are formed in the longitudinal direction by punching with a press. When the ribbon spring 13 is incorporated into the one-way clutch 10, the circumferential position of the window hole 23 corresponds to the position of the pocket 18 formed in the cage 12. Further, the annular portion 20 is provided with a substantially V-shaped bent portion 24 bent radially inward at equal intervals in the circumferential direction (see FIG. 2B).

  Refer to FIG. 1 again. After the ribbon spring 13 is incorporated into the inner periphery of the cage 12, the sprag 11 is inserted into each pocket 18 so as to push the leaf spring portion 30 away. The sprag 11 is held by the cage 12 in a state where a slight tilt is allowed in the circumferential direction.

  When the one-way clutch 10 is assembled between the inner ring 14 and the outer ring 15, the leaf spring portion 30 is in contact with the spring receiving portion 19 of the sprag 11, and the tip portion is radially inward (downward in the figure). Is pushed down). A force F determined by the spring constant of the leaf spring portion 30 and its displacement amount acts on the spring receiving portion 19 in the direction shown in FIG. By this force F, the sprag 11 is urged in the direction of biting with respect to the inner ring 14 and the outer ring 15. As a result, in the one-way clutch 10 shown in FIG. 1, when the outer ring 15 rotates in the clockwise direction relative to the inner ring 14, the sprag 11 is caught between the inner and outer rings 14 and 15, and the inner ring 14 and the outer ring 15. And rotate together. Conversely, when the outer ring 15 rotates counterclockwise relative to the inner ring 14, the sprag 11 tilts in the direction opposite to the biting direction against the elasticity of the leaf spring portion 30, and the inner and outer rings 14. , 15 interrupts the power transmission.

  As described above, the leaf spring portion 30 can bend with elasticity in the radial direction. Therefore, when energy such as vibration is input from the outside, the leaf spring portion 30 vibrates in the radial direction. For this reason, when the frequency input from the outside and the natural frequency which the leaf | plate spring part 30 has correspond, there exists a possibility that the leaf | plate spring part 30 may resonate and may be damaged. Since the one-way clutch 10 is incorporated in an automatic transmission device of a vehicle and receives external vibrations having various frequencies, it is necessary to consider that the leaf spring portion 30 does not resonate.

The natural frequency of the leaf spring portion 30 is determined by the shape and mass of the leaf spring portion 30.
The shape of the leaf spring part 30 of this embodiment will be described. FIG. 3 is an enlarged view of a main part of the ribbon spring 13 shown in FIG. For the cross-sectional shape of the ribbon spring 13 in the circumferential direction, refer to FIG.
As shown in FIG. 2B, the leaf spring portion 30 is formed with a bent portion 32 that is bent in a substantially V shape in a direction protruding outward in the radial direction. A sprag contact portion 33 that extends in the circumferential direction and contacts the spring receiving portion 19 of the sprag 11 is formed at a portion closer to the tip of the leaf spring portion 30 than the bent portion 32.
As shown in FIG. 3, the leaf spring portion 30 has an axial dimension (an “axial direction” is the axial direction of the ribbon spring 10) at a substantially central portion in the longitudinal direction. This direction is referred to as a “width direction”, and a narrow width portion 31 is formed. The narrow width portion 31 has a shape cut out in the radial direction by cutting both side surfaces 30a and 30b in the width direction of the leaf spring portion 30, and the shape viewed from the outside in the radial direction is substantially U-shaped. Shape.

The natural frequency of the leaf spring part 30 will be described with reference to FIG. FIG. 4A is a diagram schematically illustrating the shape of three types of leaf spring portions described below.
The solid line indicates the shape of the leaf spring portion 30 (hereinafter referred to as “the leaf spring portion”) in which the narrow portion 31 of the present embodiment is formed. In the leaf spring portion 30, the narrow width portion 31 is formed in a portion (position indicated by (n) in FIG. 4A) that is close to the approximate center in the longitudinal direction.
On the other hand, in order to explain in comparison with the present embodiment, an example of a leaf spring portion in which the position of the narrow width portion is changed is indicated by a broken line. In FIG. 4A, a leaf spring portion provided with the narrow width portion 41 only at the position indicated by (1) (the position closest to the bridging portion 21) is referred to as a “first comparison leaf spring portion 40”. As another comparative example, a leaf spring portion in which the narrow width portion 51 is provided only at the position indicated by (2) (the position closest to the tip of the leaf spring portion) is referred to as a “second comparison leaf spring portion 50”. .
The main leaf spring portion 30, the first comparison leaf spring portion 40, and the second comparison leaf spring portion 50 are different from each other only in the positions where the narrow width portions are formed. And compared with the conventional leaf spring portion 106 having no narrow width portion, the plate thickness, the axial length, the circumferential length, the circumferential shape, etc. (these are the main dimensions of the leaf spring portion) Are the same.

  FIG. 4B is a conceptual diagram showing a spring system common to the leaf spring portions 30, 40, 50. FIG. 4C shows the positions of the leaf spring portions 30, 40, 50 corresponding to the positions of the narrow width portions 31, 41, 51 formed in the leaf spring portions 30, 40, 50 of FIG. The natural frequency is shown. FIG. 4D shows the spring constants of the leaf spring portions 30, 40 and 50 in the same manner as FIG. 4C. In FIG. 4C and FIG. 4D, the horizontal axis indicates the dimension from the side surface 21 a of the bridging portion 21 to the narrow width portions 31, 41, 51. The dimensions to the narrow width portions 31, 41, 51 are Ln in the main leaf spring portion 30, and L1 and L2 in the first comparison leaf spring portion 40 and the second comparison leaf spring portion 50, respectively.

  In order to conceptually explain the natural frequency of the leaf spring portion, as shown in FIG. 4A, the leaf spring portion is divided into two regions P and Q having substantially the same length in the longitudinal direction. The leaf spring portion vibrates in a direction orthogonal to the paper surface. 4A supports a region Q having a mass M in a region P having a spring constant K, and represents the spring system as shown in the conceptual diagram of FIG. 4B. Yes. Here, the spring constant means that when the leaf spring portion is loaded with a load f in the radial direction (perpendicular to the paper surface in FIG. 4A), the loaded portion is displaced in the radial direction. Is a value represented by f / x.

First, the natural frequency of a conventional leaf spring portion 106 that does not have a narrow width portion will be described.
When the mass of the region Q of the conventional leaf spring portion 106 is Mo and the spring constant of the region P is Ko, the natural frequency fo of the conventional leaf spring portion 106 is expressed by the following formula 1. Note that π is the circumference ratio.
fo = (1 / 2π) √ (Ko / Mo) Equation 1
The natural frequency fo of the conventional leaf spring portion 106 is indicated by a broken line in FIG. Moreover, the spring constant Ko of the conventional leaf | plate spring part 106 is shown with a broken line in FIG.4 (d).

Next, the natural frequency of the first comparison leaf spring portion 40 will be described.
The mass of the region Q of the first comparison leaf spring portion 40 is M1, and the spring constant of the region P is K1. The natural frequency f1 of the first comparison leaf spring portion 40 is expressed by the following formula 2.
f1 = (1 / 2π) √ (K1 / M1) Equation 2
In the first comparison leaf spring portion 40, the region Q has the same shape as the conventional leaf spring portion 106, so the mass M1 of the region Q is equivalent to the mass Mo of the conventional leaf spring portion 106. On the other hand, in the first comparison leaf spring portion 40, a narrow width portion 41 is formed in the region P. In terms of material mechanics, it is known that the spring constant when the leaf spring is bent is proportional to the section modulus of the leaf spring. The section modulus is proportional to the dimension (effective length) of the leaf spring in the width direction when the plate thickness is equal. In the narrow width portion 41, since the axial dimension (effective length) is smaller than that of the conventional leaf spring portion 106, the spring constant K1 in the region P of the first comparison leaf spring portion 40 is the spring of the conventional leaf spring portion 106. Smaller than the constant Ko. For this reason, the natural frequency f1 of the first comparison leaf spring portion 40 is smaller than the natural frequency fo of the conventional leaf spring portion 106.
The natural frequency f1 of the first comparison leaf spring portion 40 is indicated by a point A1 in FIG. 4C in correspondence with the position of the narrow width portion 41. Further, the spring constant K1 of the first comparison leaf spring portion 40 is indicated by a point B1 in FIG. 4D corresponding to the position of the narrow width portion 41.

Next, the natural frequency f2 of the second comparison leaf spring portion 50 will be described.
The mass of the region Q of the second comparison leaf spring portion 50 is M2, and the spring constant of the region P is K2. The natural frequency f2 of the second comparison leaf spring portion 50 is expressed by the following formula 3.
f2 = (1 / 2π) √ (K2 / M2) Equation 3
In the second comparison leaf spring portion 50, the region P has the same shape as the conventional leaf spring portion 106, so that the spring constant K 2 in the region P is equal to the spring constant Ko of the conventional leaf spring portion 106. On the other hand, in the second comparison leaf spring portion 50, since the narrow width portion 51 is formed in the region Q, the mass M2 of the region Q is smaller than the mass Mo of the conventional leaf spring portion 106. For this reason, the natural frequency f2 of the 2nd comparison leaf | plate spring part 50 is larger than the natural frequency fo of the conventional leaf | plate spring part 106. FIG.
The natural frequency f2 of the second comparison leaf spring portion 50 is indicated by a point A2 in FIG. 4C in correspondence with the position of the narrow width portion 51. Further, the spring constant K2 of the second comparison leaf spring portion 50 is indicated by a point B2 in FIG. 4D in correspondence with the position of the narrow width portion 51.

Next, the natural frequency of the leaf spring portion 30 will be described.
In the main leaf spring portion 30, it is necessary to set the natural frequency fn of the main leaf spring portion 30 to be equal to the natural frequency fo of the conventional leaf spring portion 106. The natural frequency fo is larger than the natural frequency f1 of the first comparison leaf spring portion 40 and smaller than the natural frequency f2 of the second comparison leaf spring portion 50. Therefore, the natural frequency fn is set to be equal to the natural frequency fo of the conventional leaf spring portion 106 by selecting the dimension Ln from the side surface 21a of the bridging portion 21 to the narrow width portion 31 to be larger than L1 and smaller than L2. I can do it.
Specifically, as shown in FIG. 4C, a point A1 indicating the natural frequency of the first comparison leaf spring portion 40 and a point A2 indicating the natural frequency of the second comparison leaf spring portion 50 are connected. A straight line is obtained, and a point An where the straight line and a broken line indicating the natural frequency of the conventional leaf spring portion 106 intersect is obtained. In this leaf spring portion 30, the natural frequency fn is equal to the natural frequency fo of the conventional leaf spring portion 106 by setting the dimension from the side surface 21a to the narrow width portion 31 to the dimension from the side surface 21a to the point An. Can be made. As a result, the narrow width portion 31 of the leaf spring portion 30 is now separated from the bridging portion 21 by a predetermined dimension and is formed at a position away from the tip of the leaf spring portion 30 by a predetermined dimension. Formed in the center.
At this time, the spring constant of the main plate spring portion 30 is obtained from FIG. A straight line connecting the point B1 indicating the spring constant of the first comparison leaf spring part 40 and the point B2 indicating the spring constant of the second comparison leaf spring part 50 is obtained, and the dimension from the straight line and the side surface 21a is Ln. Obtain Bn. The spring constant Kn of the leaf spring portion 30 can be obtained from the value of the spring constant at the point Bn. The spring constant Kn of the main leaf spring portion 30 is larger than the spring constant K1 of the first comparison leaf spring portion 40 and smaller than the spring constant K2 of the second comparison leaf spring portion 50. Since the spring constant K2 of the second comparison leaf spring portion 50 is equivalent to the spring constant Ko of the conventional leaf spring portion 106, the spring constant Kn of the leaf spring portion 30 is the spring constant Ko of the conventional leaf spring portion 106. Smaller.

  Thus, in the ribbon spring 13 of the present embodiment, by appropriately setting the position where the narrow portion 31 is installed in the longitudinal direction of the leaf spring portion 30, without changing the main dimensions of the conventional leaf spring portion 106, The spring load for biasing the sprag 11 can be changed while maintaining the natural frequency of the leaf spring portion.

In the first embodiment, the narrow width portion 31 is formed such that both side surfaces 30a and 30b in the width direction of the leaf spring portion 30 are U-shaped concave portions, but is not limited to this configuration. For example, as shown in FIG. 5, in the leaf spring portion 35 of the second embodiment, a narrow width portion may be formed by providing a hole 36 penetrating in the radial direction at a substantially central portion in the width direction.
In the leaf spring portion 35 of the second embodiment, the portion closer to the bridging portion than the hole 36 and the portion closer to the tip than the hole 36 are connected on both sides in the width direction across the hole 36. For this reason, the cross section in the width direction of the leaf spring portion 35 at the position of the hole 36 has the same plate thickness and a smaller effective length in the width direction as compared with the conventional leaf spring portion 106. The effective length in the second embodiment refers to the sum of the lengths in the width direction of portions that substantially constitute the leaf spring portion 35 except for the hole 36.
Accordingly, in the leaf spring portion 35 of the second embodiment, the section coefficient of the leaf spring portion 35 can be reduced similarly to the leaf spring portion 30 of the first embodiment, so that the spring constant can be reduced. Then, by appropriately selecting the position in the longitudinal direction of the plate spring portion 35 of the hole 36 penetrating in the radial direction, the natural frequency equivalent to that of the conventional plate spring portion 106 can be set.

  Thus, in the ribbon spring of the second embodiment, the spring load for biasing the sprag 11 is changed while maintaining the natural frequency of the leaf spring portion without changing the main dimension of the conventional leaf spring portion 106. be able to. Furthermore, as compared with the ribbon spring 13 of the first embodiment, it is only necessary to process the single hole 36, so that the processing efficiency can be improved.

  Note that the shape of the narrow portion is not limited to the above example. For example, in the first embodiment, the shape viewed in the radial direction is a U-shape, but may be an arc shape.

  As described above, by using the present invention, in the sprag type one-way clutch ribbon spring, the natural frequency of the leaf spring portion is maintained without changing the main dimensions of the conventional leaf spring portion. The spring load for biasing the sprag 11 can be changed.

10: one-way clutch, 11: sprag, 12: cage, 13: ribbon spring, 14: inner ring, 15: outer ring, 16: outer ring engaging surface, 17: inner ring engaging surface, 18: pocket, 19: spring support Part, 20: annular part, 21: bridging part, 21a: side face, 23: window hole,
(First embodiment) 30: leaf spring portion, 31: narrow width portion,
(Second Embodiment) 35: leaf spring portion, 36: hole,
(First comparative example) 40: first comparative leaf spring portion, 41: narrow width portion,
(Second comparative example) 50: second comparative leaf spring portion, 51: narrow width portion,
(Conventional structure) 100: One-way clutch, 101: Sprag, 102: Cage, 103: Ribbon spring, 104: Outer ring, 105: Inner ring, 106: Leaf spring part, 107: Bridge part

Claims (5)

A pair of annular portions opposed on both axial sides;
A plurality of bridging portions that are spanned between the pair of annular portions at equal intervals in the circumferential direction and that define window holes between the circumferential directions of each other;
A leaf spring portion extending in the circumferential direction from one side surface of the bridging portion toward the window hole, and
In the sprag type one-way clutch ribbon spring in which a sprag biased by the leaf spring portion is inserted into the window hole,
The leaf spring portion has a narrow width portion formed between the bridging portion and the tip of the leaf spring portion in the circumferential direction,
The narrow width portion has an effective length in the axial direction smaller than an effective length of the leaf spring portion other than the narrow width portion in the circumferential direction.
Ribbon spring for sprag type one-way clutch. The narrow-width portion has a cross-sectional modulus of the axial cross section smaller than that of the leaf spring portion other than the narrow-width portion in the circumferential direction.
A ribbon spring for a sprag type one-way clutch according to claim 1. The narrow portion is formed by cutting out both axial side surfaces of the leaf spring portion in the radial direction.
A ribbon spring for a sprag type one-way clutch according to any one of claims 1 and 2. The narrow portion is formed by drilling in the center of the axial direction of the leaf spring portion.
A ribbon spring for a sprag type one-way clutch according to any one of claims 1 and 2. A cage with a plurality of pockets in the circumferential direction;
A plurality of sprags held in the pocket;
In a sprag type one-way clutch provided with a ribbon spring that biases the sprag,
The sprag type one-way clutch, wherein the ribbon spring is a ribbon spring according to any one of claims 1 to 4.

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