JP2007092870A - One-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way clutch capable of enhancing the compatibility of establishing both low torque at the time of idling and stable meshing performance. <P>SOLUTION: The one-way clutch 1 is structured so that sprags 4 also rotate in the circumferential direction in association with rotation of the outer ring. Each sprag 4 has a vane-form part 6 stretching axially from the end face about the axial direction and able to generate a force directed outward in the radial direction upon receiving a relative flow of fluid between the inner and outer rings when the clutch is idling. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a one-way clutch.

A one-way clutch generally has a plurality of sprags arranged between the inner ring and the outer ring at a predetermined interval in the circumferential direction. When the inner ring and the outer ring rotate relative to each other in the other direction, the sprag is disengaged and the power transmission is interrupted. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 5-126169

  The performance required for the one-way clutch includes “stable meshing” and “low torque during idling”. Among these, in order to ensure “stable meshing”, the one-way clutch is provided with a biasing member such as a ribbon spring to bias the sprags in the meshing direction. However, since the biasing member biases the sprags in the meshing direction even during idling, it increases the contact between the sprags and the inner and outer rings during idling and is a factor that hinders "low torque during idling". Become.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a one-way clutch capable of enhancing compatibility between low torque during idling and stable meshing.

A one-way clutch according to the present invention includes an outer ring and an inner ring, a plurality of sprags arranged at predetermined intervals in the circumferential direction between the inner and outer rings, and a sprag urging member that urges the sprags in a meshing direction. In the one-way clutch in which the sprag rotates in the circumferential direction as it rotates,
The sprag has a blade-like portion that extends in the axial direction from its axial end face and can generate a radially outward force by receiving a relative flow of fluid between the inner and outer rings at the time of clutch idling. To do.
In this way, a force in the direction of separating the sprag from the inner ring can be generated by utilizing the relative flow of fluid (lubricant oil, air, etc.) during idling of the clutch, and the frictional force between the sprag and the inner ring can be generated. Can be reduced. Therefore, the idling torque can be reduced in the one-way clutch of the type in which the sprag rotates in the circumferential direction along with the outer ring rotation. Further, since the blade-like portion extends in the axial direction from the axial end surface of the sprag, the blade-like portion is located outside the rotation range (axial range) of the sprag. Therefore, the fluid impinging on the blade-like portion due to the so-called pump effect is less likely to be diluted, and the force received by the blade-like portion from the fluid is increased.

In the one-way clutch, the blade-like portion may be a plate-like member that can generate a radially inward force in response to a relative flow of the fluid during clutch engagement rotation.
In this case, a force for pressing the sprags toward the inner ring side can be generated using the relative flow of the fluid during the clutch engagement rotation. In other words, the plate-like member generates a force in a direction to disengage the sprag from the inner ring when the clutch is idling, and generates a force that presses the sprag toward the inner ring when the clutch is engaged. Therefore, it is possible to further improve the compatibility between the low torque during idling and the stability of meshing.

Another aspect of the present invention provides an outer ring and an inner ring, a plurality of sprags arranged at predetermined intervals in the circumferential direction between the inner and outer rings, a retainer for holding these sprags, and a sprag for biasing the sprags in the meshing direction. In the one-way clutch provided with an urging member, the retainer or the sprag receives a relative flow of fluid between the inner and outer rings during idling of the clutch and generates a moment for rotating the sprag in the meshing release direction. It is a one-way clutch characterized by having a protrusion that generates a moment for rotating the sprags in the meshing direction by receiving a relative flow of fluid between the inner and outer rings during clutch meshing rotation.
In this case, the projecting portion may utilize the force of fluid between the inner and outer rings to generate a moment for rotating the sprag in the mesh release direction during idling and to generate a moment for rotating the sprag in the mesh direction during mesh rotation. As a result, compatibility between stable meshing and low torque during idling is further enhanced.

  The projection can be provided on either (or both) of the sprag or the cage. However, the invention of the one-way clutch provided with the projection on the cage has the feature that the sprag rotates in the circumferential direction as the outer ring rotates. In the one-way clutch, the retainer includes an inner retainer for retaining an inner portion of the sprag by a sprag pocket provided at a predetermined interval in the circumferential direction, and a sprag pocket provided at a predetermined interval in the circumferential direction. It consists of an outer holder that holds the outer portion of the sprag, and holds the sprag while inclining in the meshing release direction by making the phase of the sprag pocket different between the inner and outer holders, and the protrusion is It is provided in the inner cage and protrudes so that a force in the direction opposite to the direction of rotation of the outer ring can be applied to the inner cage by the relative flow of the fluid. And it is characterized in Rukoto.

In this case, since the sprag rotates in the circumferential direction along with the rotation of the outer ring, the relative flow direction of the fluid with respect to the sprag is opposite to the rotation direction of the outer ring. Then, by providing a protrusion on the retainer so as to receive the relative flow of the fluid, the retainer can obtain a force in the relative flow direction of the fluid, that is, a force opposite to the rotation of the outer ring.
Here, when the clutch is idling, the outer ring is rotated in the sprag tilt direction during idling, so the relative flow direction of the fluid is opposite to the sprag tilt direction. When rotation in the direction opposite to the sprag tilt direction is applied to the inner cage, the inner cage holds the inner side of the sprag more than the outer cage, so that the inclination angle of the sprag in the mesh release direction is increased (that is, A force that causes the sprags to rotate in the meshing release direction acts on the sprags. Therefore, the torque during idling can be reduced.
Further, when the clutch meshing rotation is considered, in this case, since the outer ring (and the inner ring and the sprag) is rotated in the direction opposite to the sprag tilt direction, the relative flow direction of the fluid is the same as the sprag tilt direction. Become. When the inner cage is rotated in the same direction as the sprag tilting direction, the inner cage holds the inner side of the sprag more than the outer cage, so the inclination angle of the sprag in the mesh release direction is reduced (that is, A force that rotates the sprags in the meshing direction acts on the sprags. Therefore, the meshing stability can be increased.

  The torque during idling can be reduced using the relative flow of fluid between the inner and outer rings, and compatibility between low torque during idling and stable meshing can be improved.

Embodiments of the present invention will be described below with reference to the drawings.
In the following description, “radial direction” and “circumferential direction” mean the radial direction and the circumferential direction of the clutch (or inner and outer rings).
FIG. 1 is a side view of a clutch (hereinafter also simply referred to as a clutch) 1 according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of the clutch 1. The one-way clutch 1 includes an outer ring and an inner ring (not shown), a plurality of sprags 4 equally distributed in the circumferential direction between the inner and outer rings, and a sprag biasing member that biases the sprags 4 in the meshing direction. The ribbon spring 5 is provided. Further, each sprag 4 is held by the inner holder 2 and the outer holder 3. In FIG. 1, the description of the blade-like portion 6 described later is omitted in order to avoid the drawing from being complicated.

  Ribbon springs 5 (shown by thick lines in FIGS. 1 and 2) are generally annular, and are provided at predetermined intervals in the circumferential direction to accommodate sprags 4 and to the inside of the pockets 5p. And a tongue-like leaf spring portion 5a protruding toward the top (see FIG. 2). The ribbon spring 5 rotates with the sprag 4 rotating. The tip of the leaf spring portion 5a is always in contact with the sprag 4 regardless of the posture of the sprag 4, and urges the sprag 4 to rotate in the meshing direction.

  Each of the inner cage 2 and the outer cage 3 has a substantially annular shape as a whole, and has sprag pockets at predetermined intervals in the circumferential direction. Of these, the inner cage 2 holds the inner part of the sprag 4 by sprag pockets 2p (see FIG. 2) provided at predetermined intervals in the circumferential direction. The outer cage 3 holds the outer portion of the sprag 4 by sprag pockets 3p provided at predetermined intervals in the circumferential direction. The sprags 4 are held while being inclined in the mesh release direction by making the phases of the sprag pockets 2p and 3p different between the inner and outer holders 2 and 3.

  In the clutch 1, the outer cage 3 is fixed to the outer ring. That is, as shown in FIG. 1, the outer retainer 3 has flanges (protrusions) 3a provided on the outer peripheral edge thereof at predetermined intervals in the circumferential direction and extending outward in the radial direction. Is set to be slightly larger than the inner diameter of the outer ring. The outer cage 3 is fixed to the outer ring by fitting the outer cage 3 to the inner circumferential surface of the outer ring while pressing the outer surface of the flange 3a against the inner circumferential surface 11 of the outer ring. Thus, since the outer cage 3 is fixed to the outer ring, when the outer ring rotates, the outer cage 3 rotates along with it, and the sprag 4 held by the outer cage 3 also rotates in the circumferential direction ( Move in the circumferential direction). The sprag 4 can be rotated together with the outer ring. In addition to the case where the sprag 4 is rotated by the cage fixed on the outer ring side as described above, for example, the sprag 4 is pivotally supported on the outer ring side. In addition, a method without using a cage can also be adopted. In FIG. 1, the outer cage 3 is fixed to the outer ring by the protruding portion. However, the shape of the outer cage 3 is not limited, and a method of fixing to the outer ring using another part can also be adopted.

  One inner cage 2 is not fixed to the inner ring, and the inner cage 2 and the inner ring can freely rotate relative to each other. Further, the inner cage 2 is not fixed to the outer cage 3. However, since both the inner cage 2 and the outer cage 3 hold a common sprag 4, when the outer cage 3 rotates due to the rotation of the outer ring, the inner cage 2 also rotates accordingly.

  The one-way clutch 1 is engaged when an outer ring and an inner ring (not shown) are relatively rotated in one direction (for example, the outer ring is rotated in the direction of arrow a in FIG. 2), and power is transmitted between the inner and outer rings. On the other hand, when the outer ring and the inner ring are relatively rotated in the other direction (for example, the inner ring is rotated in the direction of arrow b in FIG. 2), the sprag 4 is tilted to disengage the sprag 4 from the inner ring. Idle each other.

  FIG. 3 is a cross-sectional view of the sprag 4 taken along line AA in FIG. The sprag 4 has a blade-like portion 6 that extends in the axial direction from the axial end face thereof and can generate a radially outward force by receiving a relative flow of fluid between the inner and outer rings during idling of the clutch. . The blade-like portion 6 is a substantially flat plate-like member 62, and when the outer ring is rotated in the idling direction (arrow b direction in FIG. 2), the outer ring idling direction is opposite to the outer ring idling direction (arrow c direction in FIG. 2). Is inclined with respect to the tangential direction in the circumferential direction of the clutch so as to generate a radially outward force F1 in response to the relative flow of fluid (such as lubricating oil or air) generated in the clutch. Here, the radially outward force means a force having a radially outward component.

The radially outward force F1 can reduce the frictional force between the sprag 4 and the inner ring inner peripheral surface 10 (indicated by a two-dot chain line in FIG. 2), or the sprag 4 and the inner ring inner peripheral surface 10 can be separated. Can be made. Therefore, the torque during idling can be reduced.
Further, since the plate-like member 62 is inclined with respect to the tangential direction in the circumferential direction of the clutch as described above, it occurs in the direction opposite to the meshing rotation direction (arrow d in FIG. 2) during the clutch meshing rotation. When the relative flow of the fluid hits, a radially inward force F2 is generated. Here, the radially inward force means a force having a radially inward component. Due to the radially inward force F2, the sprag 4 is pressed against the inner ring inner peripheral surface 10, and the frictional force between the sprag 4 and the inner ring inner peripheral surface 10 increases. Note that the plate-like member 62 is not limited to a flat plate shape, and may be, for example, a curved surface.
As described above, the plate-like member 62 as the blade-like portion 6 generates a force F1 in a direction to disengage the sprag 4 from the inner ring when the clutch is idling, and generates a force F2 that presses the sprag 4 toward the inner ring when the clutch is engaged. To do. Therefore, compatibility between the low torque during idling and the stability of meshing is enhanced.

  FIG. 4 is a side view of the sprag 4 provided with a blade-like portion of a modified example. The wing-like portion 61 has a cross section shaped like an airplane wing. In other words, the cross-sectional shape of the blade-like portion 61 is such that its radially outer side surface (upper surface in FIG. 4) 61a bulges in a convex shape with a smooth curve, while its radially inner side surface (lower surface in FIG. 4) 61b is substantially the same. It is a flat surface. Further, the thickness (diameter thickness) of the blade-like portion 61 is such that the front end where the fluid in the relative flow direction (in the direction of arrow c in FIG. 2) first hits is relatively thick, and goes toward the rear end. The shape gradually fades. In this way, the above-described radial outward force F1 can be effectively increased by the same principle as that in which the airplane wing generates lift, which contributes to a reduction in torque during idling.

FIG. 5 is an enlarged cross-sectional view of the one-way clutch 20 according to the second embodiment of the present invention. Since the basic configuration of the one-way clutch 20 is the same as that of the clutch 1 described above, the description of the same configuration as the clutch 1 is omitted below.
In the one-way clutch 20, the sprag 4 does not have a blade-like portion, and the sprag 4 is the same as the conventional one. The shape of the inner cage 2 is different from that of the clutch 1. The inner cage 2 has a protrusion 7 that can generate a moment that causes the sprag 4 to rotate in the meshing release direction in response to the relative flow of fluid between the inner and outer rings during idling of the clutch. FIG. 6 is a perspective view of the inner cage 2 in which the vicinity of the protrusion 7 is enlarged. The protrusion 7 receives a force F3 in the same direction as the fluid flow direction (force opposite to the inclination direction of the sprag 4) F3 due to the fluid flow in the flow direction (arrow c direction) generated during idling of the clutch (see FIG. 5). This force F3 acts in the direction of increasing the phase shift between the outer retainer 3 and the inner retainer 2 (the phase shift between the sprag pocket 2p holding the same sprag 4 and the sprag pocket 3p). The moment that tries to rotate in the mesh release direction acts. Therefore, the torque during idling is reduced.

  On the other hand, the inner cage 2 receives a force F4 in the same direction as the fluid flow direction (a force in the same direction as the inclination direction of the sprag 4) F4 by the fluid flowing in the relative flow direction (arrow d direction) during clutch engagement rotation. The direction of the force F4 is opposite to the force F3 described above. This force F4 acts in a direction to reduce the phase shift between the outer cage 3 and the inner cage 2 (the phase shift between the sprag pocket 2p holding the same sprag 4 and the sprag pocket 3p). A moment acts to rotate in the meshing direction. Therefore, the meshing stability is improved.

  As described above, the protrusion 7 only needs to be able to receive the relative flow of the fluid, so that the shape thereof is not particularly limited as long as it has a surface on which the relative flow of the fluid strikes. For example, in the embodiment of FIG. 5, the protrusion 7 extends obliquely with respect to the circumferential tangential direction, but may extend along the radial direction.

  As shown in FIG. 6, the protrusion 7 is provided on the outer side in the axial direction than the axial region in which the sprag 4 rotates (substantially equal to the axial range of the sprag pocket 2 p). Therefore, as in the case of the blade-like portion 6 described above, the influence of fluid dilution due to the pump effect is suppressed to a minimum, and the force from the fluid can be received more effectively.

  The inner cage 2 in FIGS. 5 and 6 is made of metal and produced by press molding. By making the cage having the protrusions 7 into a shape that can be press-molded, the manufacturing cost of the cage can be reduced.

  In the embodiment of FIG. 5, the protrusion is provided on the cage, but the protrusion can also be provided on the sprag 4. FIG. 7 shows a modification using a sprag 4 of a modified example in which a protrusion 71 capable of generating a moment for rotating the sprag 4 in the meshing release direction by receiving a relative flow of fluid between the inner and outer rings during idling of the clutch. 3 is a side view of a directional clutch 30. FIG. In the one-way clutch 30, the protrusions 71 are plate-like members that protrude in the axial direction from both axial end surfaces of the sprag 4 and are oriented substantially in the radial direction. Similar to the inner cage 2 described above, this protrusion 71 receives a force F5 in the same direction as the fluid flow direction due to the fluid flow in the flow direction (arrow c direction) generated during idling of the clutch, and during clutch engagement rotation. Also receives a force F6 in the same direction as the relative flow direction of the fluid (arrow d direction). Since the upper part of the sprag 4 is constrained by the outer holder 3 and the inner holder 2 holding the lower part of the engaging element 4 is rotatable in the circumferential direction, the same principle as that of the second embodiment described above. Thus, a moment that rotates in the mesh release direction acts on the sprag 4. That is, a moment that rotates in the meshing release direction is generated in the sprag 4 by the force F5, and a moment that rotates in the meshing direction is generated in the sprag 4 by the force F6. Therefore, also in this case, it is possible to improve both the torque reduction during idling and the stability of meshing.

  In each of the above embodiments, the protrusion 7 and the blade-like portion 6 are provided separately. However, the protrusion 7 of the inner cage 2 and the blade-like portion 6 of the sprag 4 may be used in combination. Moreover, you may provide a projection part in both a holder | retainer and a sprag.

  The present invention is preferably applied to a one-way clutch for a torque converter disposed in an automatic transmission. In this case, since a large amount of lubricating oil exists between the inner and outer rings, the force received from the fluid is greater than when the fluid is air, and the effects of the present invention are further enhanced. In addition, in the case of such a one-way clutch for a torque converter, since the idling rate is relatively high and generally the outer ring rotates, the reduction in torque during idling greatly contributes to the improvement of fuel consumption. The one-way clutch of the invention is preferred.

It is a side view of the one way clutch which is one embodiment of the present invention. It is an expanded sectional view of the one-way clutch of FIG. It is sectional drawing of the sprag in the AA line of FIG. It is sectional drawing of the sprag which has a blade-shaped part of a modification. It is an expanded sectional view of the one-way clutch of 2nd Embodiment. FIG. 6 is a perspective view of an inner cage in the one-way clutch of FIG. 5. It is a side view of the sprag which has a projection part of a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 One-way clutch 2 Inner cage 2p Inner cage sprag pocket 3 Outer cage 3p Outer cage sprag pocket 4 Sprag 5 Ribbon spring 6 Blade-like portion 61 Blade-like portion 62 Plate-like member 7 Projection portion 71 Projection portion F1 Radially outward force F2 Radially inward force 20 One-way clutch

Claims (4)

An outer ring and an inner ring; a plurality of sprags arranged at predetermined intervals in the circumferential direction between the inner and outer rings; and a sprag urging member that urges the sprags in a meshing direction. In the one-way clutch that rotates
The sprag has a blade-like portion that extends in the axial direction from its axial end face and can generate a radially outward force by receiving a relative flow of fluid between the inner and outer rings at the time of clutch idling. One way clutch to do.   2. The one-way clutch according to claim 1, wherein the blade-like portion is a plate-like member capable of generating a radially inward force in response to a relative flow of the fluid during clutch engagement rotation. A plurality of sprags arranged at predetermined intervals in the circumferential direction between the inner and outer rings, a retainer that holds these sprags, and a sprag biasing member that biases the sprags in the meshing direction. In one-way clutch
The retainer or the sprag receives a relative flow of fluid between the inner and outer rings during idling of the clutch, generates a moment for rotating the sprag in the mesh release direction, and fluid between the inner and outer rings during clutch engagement rotation. A one-way clutch characterized by having a protrusion that generates a moment for rotating the sprags in the meshing direction in response to the relative flow. The one-way clutch according to claim 3, wherein the sprag rotates in the circumferential direction as the outer ring rotates.
The retainer retains an inner portion of the sprag by a sprag pocket provided at a predetermined interval in the circumferential direction and an outer portion of the sprag by a sprag pocket provided at a predetermined interval in the circumferential direction. It consists of an outer cage and holds the sprags while inclining in the mesh release direction by making the phase of the sprag pockets different between the inner and outer cages,
The protrusion is provided in the inner cage, and protrudes so as to apply a force in a direction opposite to the direction of rotation of the outer ring to the inner cage by the relative flow of the fluid. clutch.

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