JP2023072829A - Ratchet type one-way clutch - Google Patents

Abstract

To provide a ratchet type one-way clutch capable of improving durability without requiring complicated assembling work.SOLUTION: A claw member 3 has an inner diameter side surface 45 in contact with a teeth portion 5 when an inner ring 9 idles with respect to an outer ring 7. When viewed from a center axis C direction of the inner ring 9, assuming a contact point between the inner diameter side surface 45 and the teeth portion 5 as a contact P, a straight line vertically intersecting the center axis C and passing through the contact P as a straight line A, a straight line vertically intersecting the straight line A, passing through the contact P and orthogonal to the center axis C direction as a straight line B, a tangent at the contact point P about the inner diameter side surface 45 as a tangent T, and the size of an angle between the straight line B and the tangent T as α, the range of α satisfies a predetermined conditional expression.SELECTED DRAWING: Figure 1

Description

The present invention relates to a ratchet-type one-way clutch used as a torque transmission mechanism in vehicles, industrial machinery, and the like.

BACKGROUND ART In recent years, ratchet-type one-way clutches have been increasingly used as one-way clutches used in motorized driving devices and the like because of their reliability and controllability in engagement.

2. Description of the Related Art In a ratchet-type one-way clutch used in an electric drive device or the like, for example, when an electric motor is used as a power source, there is concern that the durability of the parts group may be reduced due to high-speed rotation. Patent Documents 1 and 2 describe a ratchet type one-way clutch with improved durability.

Patent Document 1 describes a ratchet-type one-way clutch in which a cylindrical support member is used to support a spring to stabilize the behavior of the spring and suppress wear and breakage of the spring, thereby improving durability. there is
Patent Document 2 discloses a ratchet type ratchet type in which a coil-shaped spring is attached to an outer ring via a spring seat so that one end of the spring is supported by the flat surface of the spring seat, thereby suppressing vibration of the spring and improving durability. A one-way clutch is mentioned.

JP 2017-110707 A JP 2017-101758 A

However, in the ratchet-type one-way clutches of Patent Documents 1 and 2, in addition to the conventional components, a component for holding the spring is added to stabilize the behavior of the spring, thereby suppressing breakage of the component. This improves the durability of the ratchet type one-way clutch. Therefore, in the ratchet-type one-way clutches of Patent Documents 1 and 2, there is a concern that the number of parts increases, the assembly work becomes complicated, and the cost increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ratchet type one-way clutch that can improve durability without requiring complicated assembly work.

In order to solve the above problems, the ratchet type one-way clutch according to the present invention includes:
a first annular member;
a second annular member arranged coaxially with and rotatable relative to the first annular member;
a ratchet mechanism capable of engaging the first annular member and the second annular member so as to transmit torque;
The ratchet mechanism includes a plurality of teeth provided on the first annular member;
It is provided on the second annular member and engages with the tooth portion to lock the relative rotation of the first annular member with respect to the second annular member in the first rotational direction and rotate in the second rotational direction. a plurality of pawl members that allow relative rotation of the
a plurality of elastic members for urging the plurality of claw members in a direction of meshing with the tooth portion;
the pawl member has a curved surface that contacts the tooth portion when the first annular member rotates relative to the second annular member in the second rotational direction;
When viewed from the central axis direction of the first annular member, the point of contact between the curved surface and the tooth portion is defined as a point of contact P, the straight line perpendicular to the central axis and passing through the point of contact P is defined as a straight line A, and the straight line A and A straight line that intersects perpendicularly, passes through the point of contact P and is orthogonal to the direction of the central axis is defined as a straight line B, a line tangent to the curved surface at the point of contact P is defined as a tangent line T, and the angle formed by the straight line B and the tangent line T is defined as: When the size is α, the range of α satisfies the following conditional expression.
10°<α<15°

According to the present invention, it is possible to provide a ratchet type one-way clutch that can improve durability without requiring complicated assembly work.

FIG. 1 is a front view showing a main part of a ratchet-type one-way clutch according to an embodiment, showing a non-meshing state between pawl members and tooth portions.

A ratchet type one-way clutch according to embodiments of the present invention will be described below with reference to the drawings.
First, the direction of the ratchet type one-way clutch in this embodiment will be defined. In this embodiment, the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction with respect to the center axis C of the ratchet type one-way clutch, that is, the center axis C of the outer ring and the inner ring. Regarding the axial direction, in FIG. 1, the front side of the paper surface is defined as one axial direction side or the front side, and the back side of the paper surface is defined as the other axial direction side. Regarding the circumferential direction, the direction rotating clockwise toward the plane of FIG. 1 is defined as one side in the circumferential direction, and the direction rotating counterclockwise toward the plane of FIG.

Regarding the direction of rotation of the ratchet clutch, the rotation of the outer ring and the rotation of the inner ring are relative. For example, if the inner ring can rotate clockwise, the outer ring can also rotate counterclockwise, and even if the inner and outer rings rotate in the same direction, the rotational speeds of the outer and inner rings must be different. For example, it can be said that the outer ring and the inner ring are relatively rotating in one direction.

FIG. 1 is a front view showing a main part of a ratchet type one-way clutch 1 according to the embodiment as viewed from one axial side, showing a non-meshing state between a pawl member 3 and a tooth portion 5. FIG.
A ratchet-type one-way clutch 1 according to the present embodiment has an overall annular shape when viewed from the axial direction, similar to the shape shown in FIG. toothing 5; In FIG. 1, only one claw member 3 and its peripheral portion are shown.

A ratchet-type one-way clutch 1 according to this embodiment includes an annular outer ring 7, an annular inner ring 9 arranged radially inwardly of the outer ring 7 coaxially with the outer ring 7 and rotatable relative to the outer ring 7; and a ratchet mechanism that enables transmission of torque between the inner ring 9 and the inner ring 9 .

A large number of tooth portions 5 projecting radially outward and extending in the axial direction are formed on the outer peripheral surface of the inner ring 9 at equal intervals in the circumferential direction. A space 11 having a predetermined width in the circumferential direction is formed by the tooth portions 5 adjacent in the circumferential direction. The tooth portion 5 has a substantially rectangular cross-sectional shape when viewed in the axial direction, and includes a surface 13 on one side in the circumferential direction, a surface 15 on the other side in the circumferential direction, an outer diameter side end of the surface 13 on the one side in the circumferential direction, and a circumferential direction. It has an outer diameter side surface 17 that connects the outer diameter side end of the other side surface 15 in the circumferential direction. A surface 17 on the outer diameter side of the tooth portion 5 is formed as a flat surface parallel to the axial direction or a curved surface that bulges slightly outward in the radial direction. The tooth portion 5 extends from one axial end to the other axial end of the inner ring 9 .

A shaft hole (not shown) is formed in the center of the inner ring 9, and a drive shaft (not shown) such as an electric motor is fitted in the shaft hole.

A plurality of pawl member holding portions 21 are formed in the inner peripheral portion of the outer ring 7 at predetermined intervals in the circumferential direction. The claw member holding portion 21 is a concave portion that opens radially inward and is recessed radially outward. Further, a first concave portion 23 and a second concave portion 25 are formed in order from one side in the circumferential direction toward the other side in the circumferential direction at the bottom portion of the claw member holding portion 21 . The first recessed portion 23 is recessed radially outward on one side in the circumferential direction. The second recess 25 is recessed toward the other side in the circumferential direction and radially outward.

The claw member 3 has a cylindrical portion 41 extending in the axial direction and a claw portion 43 extending from the cylindrical portion 41 in the other circumferential direction. The cylindrical portion 41 and the claw portion 43 are integrally formed. The claw portion 43 has a predetermined radial thickness, an inner diameter side surface 45 , an outer diameter side surface 47 , the other circumferential end of the inner diameter side surface 45 and the other circumferential direction of the outer diameter side surface 47 . and a tip surface 49 connecting the ends in a substantially radial direction. A surface 45 on the inner diameter side of the claw portion 43 faces the tooth portion 5 of the inner ring 9 in the radial direction. The claw member 3 is rotatably held in the first concave portion 23 of the claw member holding portion 21 at the cylindrical portion 41 . That is, the claw member 3 is held in the first concave portion 23 so that the claw portion 43 can swing in the radial direction about the cylindrical portion 41 .

A single coiled spring 51 that biases the pawl member 3 toward the inner ring 9 is arranged in the second concave portion 25 of the pawl member holding portion 21 . Specifically, the spring 51 contacts the outer diameter side surface 47 of the claw portion 43 of the claw member 3 and biases the claw portion 43 toward the inner ring 9 side. With this configuration, the pawl member 3 is always urged by the spring 51 in the meshing direction with the tooth portion 5 .

In this manner, one claw member holding portion 21 holds a set of the claw member 3 and the spring 51 . A ratchet mechanism is composed of the tooth portion 5 of the inner ring 9, the pawl member 3 held by the pawl member holding portion 21, and the spring 51. As shown in FIG. In this embodiment, the spring 51 is coil-shaped, but the shape of the spring 51 is not limited to this.

A spline (not shown) is formed on the outer peripheral portion of the outer ring 7, and the spline is connected to a driven device (not shown) to which a driving force such as an electric motor (not shown) is transmitted (not shown). omitted) are fitted. Alternatively, the outer ring 7 may be fixed and the ratchet type one-way clutch 1 may be used as a backstop.

In the ratchet type one-way clutch 1 of the present embodiment, the relative rotation of the inner ring 9 with respect to the outer ring 7 is fixed when the inner ring 9 rotates clockwise in FIG. The inner ring 9 idles against .

Specifically, when the inner ring 9 rotates clockwise, the plurality of pawl members 3 of the outer ring 7 mesh with the tooth portions 5 of the inner ring 9 respectively. Specifically, the meshing between the pawl member 3 and the tooth portion 5 is such that the tip end surface 49 of the pawl portion 43 that is depressed into the space 11 between the tooth portions 5 by the biasing force of the spring 51 is aligned with the tooth portion 5 in the circumferential direction. This is done by engaging with the surface 13 on one side. In this manner, the surface 13 on one side in the circumferential direction of the toothed portion 5 of the inner ring 9 constitutes a meshing surface of the toothed portion 5 that meshes with the pawl member 3 of the outer ring 7 . In addition, in the following description, the surface 13 on one side in the circumferential direction of the tooth portion 5 is also referred to as "the meshing surface 13 of the tooth portion 5". When the pawl member 3 and the toothed portion 5 mesh with each other, the outer ring 7 and the inner ring 9 rotate together, and torque is transmitted from the inner ring 9 to the outer ring 7 . Alternatively, when the outer ring 7 is fixed, the rotation of the inner ring 9 with respect to the outer ring 7 is fixed, so it functions as a backstop that prevents the inner ring 9 from rotating clockwise.

On the other hand, when the inner ring 9 rotates counterclockwise, the plurality of pawl members 3 do not mesh with the teeth 5 of the inner ring 9 and the inner ring 9 idles with respect to the outer ring 7 . Specifically, the pawl portion 43 of the pawl member 3 is pushed up radially outward by the tooth portion 5 of the inner ring 9 against the biasing force of the spring 51, allowing the inner ring 9 to rotate. In this state, torque is not transmitted from the inner ring 9 to the outer ring 7 . Thus, the ratchet mechanism switches the inner ring 9 and the outer ring 7 between the torque transmission state and the torque non-transmission state.

The ratchet type one-way clutch 1 according to this embodiment has a structure in which the pawl member 3 exhibits stable behavior when the inner ring 9 rotates counterclockwise and idles with respect to the outer ring 7 . The configuration of the ratchet mechanism of the ratchet type one-way clutch 1 according to this embodiment will be described in more detail below. In the following description, the case where the inner ring 9 rotates with respect to the outer ring 7 will be described as an example.

In the ratchet type one-way clutch 1 of the present embodiment, a surface 45 on the inner diameter side of the pawl portion 43 of the pawl member 3 is formed into a curved surface that protrudes radially inward. Specifically, the surface 45 on the inner diameter side of the claw portion 43 is formed into a curved surface whose cross-sectional shape when viewed in the axial direction is an arc that bulges radially inward. That is, the inner diameter side surface 45 of the claw portion 43 is a partially cylindrical outer peripheral surface. From the state in which the claw portion 43 of the claw member 3 is engaged with the tooth portion 5, that is, the state in which the tip surface 49 of the claw portion 43 is engaged with the meshing surface 13 of the tooth portion 5, the inner ring 9 is rotated counterclockwise in FIG. When the tooth portion 5 of the inner ring 9 rotates, the ridge portion 61 between the surface 17 on the outer diameter side and the surface 15 on the other side in the circumferential direction moves over the surface 45 on the inner diameter side of the claw portion 43 from one side in the circumferential direction. It slides toward the other side in the circumferential direction. As the ridge portion 61 moves toward the other side in the circumferential direction on the inner diameter side surface 45 of the claw portion 43, the claw portion 43 is pushed upward in the radial direction.

The inner ring 9 further rotates counterclockwise, the tooth portion 5 moves in the other circumferential direction with respect to the pawl portion 43 , and the ridge portion 61 of the tooth portion 5 moves to the other circumferential side of the inner diameter side surface 45 of the pawl portion 43 . After that, as the tooth portion 5 moves in the other circumferential direction with respect to the claw portion 43, the tip of the claw portion 43, i. It slides on the surface 17 on the outer diameter side of the portion 5 relatively toward one side in the circumferential direction. When the other circumferential end of the inner diameter side surface 45 of the pawl portion 43 slides to the one circumferential end of the outer diameter side surface 17 of the tooth portion 5 , the space between the tooth portions 5 is opened by the biasing force of the spring 51 thereafter. Get down to 11. That is, the tip portion of the claw portion 43 falls into the space 11 between the tooth portions 5 . The pawl member 3 and the tooth portion 5 repeat such behavior while the inner ring 9 is rotating counterclockwise.

Here, when viewed from the axial direction, when the ratchet type one-way clutch 1 idles, that is, when the inner ring 9 idles with respect to the outer ring 7, the surface 45 on the inner diameter side of the claw portion 43 and the ridge portion 61 of the tooth portion 5 or A point of contact with the surface 17 on the outer diameter side is defined as a point of contact P, and a straight line perpendicular to the center axis C of the inner ring 9 and passing through the point of contact P is defined as a straight line A. Further, a straight line perpendicular to the straight line A, passing through the point of contact P and perpendicular to the direction of the center axis C is called a straight line B. Furthermore, the tangent line at the point of contact P with respect to the inner diameter side surface 45 of the claw portion 43 is defined as the tangent line T, and the angle formed by the straight line B and the tangent line T is defined as α. In addition, the straight line A, the straight line B, and the tangent line T in FIG. 1 are all imaginary lines.

The ratchet type one-way clutch 1 of this embodiment is constructed so that the range of α satisfies the following conditional expression (1).
(1) 10°<α<15°

That is, the ratchet-type one-way clutch 1 of this embodiment is constructed such that the shape of the inner diameter side surface 45 of the pawl member 3 that contacts the tooth portion 5 satisfies the conditional expression (1). As described above, the position of the contact point P on the inner diameter side surface 45 of the pawl member 3 is displaced as the inner ring 9 rotates. Any position on the surface 45 is configured to satisfy the conditional expression (1). Specifically, the shape of the inner diameter side surface 45 of the claw member 3 is configured such that the radius of curvature and the length in the circumferential direction satisfy the conditional expression (1).

In the ratchet type one-way clutch 1 of this embodiment, the shape of the inner diameter side surface 45 of the pawl member 3 satisfies the conditional expression (1), so that the pawl member 3 and the plurality of tooth portions 5 are continuous during idling. Radial swinging of the claw member 3 due to contact can be reduced. With such a configuration, the ratchet type one-way clutch 1 of the present embodiment stabilizes the behavior of the spring 51 during idling, suppresses damage to the spring 51 and the peripheral parts of the spring 51, and improves durability. can be planned. Further, since the behavior of the spring 51 is stabilized, it becomes possible to apply a spring having a conventionally used structure to the ratchet type one-way clutch 1 rotating at high speed.

If the shape of the radially inner surface 45 of the pawl member 3 is out of the range defined by conditional expression (1), the pawl member 3 will swing in the radial direction due to continuous contact between the pawl member 3 and the tooth portion 5 during idling. becomes large and it becomes difficult to stabilize the behavior of the spring 51, which is not preferable.

As described above, according to the present embodiment, it is possible to realize the ratchet type one-way clutch 1 that does not require complicated assembly work and that can suppress an increase in cost.
It should be noted that the present invention is not limited to the above embodiments, and can be modified as appropriate. For example, it can be applied to a ratchet type one-way clutch in which the pawl member 3 is provided on the outer peripheral portion of the inner ring 9 and the tooth portion 5 is provided on the inner peripheral portion of the outer ring 7 .

1 ratchet type one-way clutch 3 pawl member 5 tooth portion 7 outer ring 9 inner ring 13 one circumferential side surface 15 other circumferential side surface 17 outer diameter side surface 21 pawl member holding portion 41 cylindrical portion 43 pawl portion 45 inner diameter side surface 51 spring

Claims (1)

a first annular member;
a second annular member arranged coaxially with and rotatable relative to the first annular member;
a ratchet mechanism capable of engaging the first annular member and the second annular member so as to transmit torque;
The ratchet mechanism includes a plurality of teeth provided on the first annular member;
It is provided on the second annular member and engages with the tooth portion to lock the relative rotation of the first annular member with respect to the second annular member in the first rotational direction and rotate in the second rotational direction. a plurality of pawl members that allow relative rotation of the
a plurality of elastic members for urging the plurality of claw members in a direction of meshing with the tooth portion;
the pawl member has a curved surface that contacts the tooth portion when the first annular member rotates relative to the second annular member in the second rotational direction;
When viewed from the central axis direction of the first annular member, the point of contact between the curved surface and the tooth portion is defined as a point of contact P, the straight line perpendicular to the central axis and passing through the point of contact P is defined as a straight line A, and the straight line A and A straight line that intersects perpendicularly, passes through the point of contact P and is orthogonal to the direction of the central axis is defined as a straight line B, a line tangent to the curved surface at the point of contact P is defined as a tangent line T, and the angle formed by the straight line B and the tangent line T is defined as: A ratchet type one-way clutch characterized in that the range of α satisfies the following conditional expression, where α is the size.
10°<α<15°

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