JP2006097770A - One-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way clutch used in a stator of a gear shift mechanism of an automobile and capable of reducing friction while preventing occurrence of improper meshing in a region in which the number of revolutions is small to improve fuel economy. <P>SOLUTION: This sprag type one-way clutch 1 for transmitting rotation power of either of an inner ring 9 and an outer ring 7 to the other or shutting off the transmission of rotation power is provided with an annular cage 13 having a plurality of pockets 14 in the circumferential direction, a plurality of sprags 4 held in each pocket 14, and a plurality of elastic bodies 11, 12 for energizing each sprag 4 in the direction in which it meshes with the inner ring 9 and the outer ring 7. Spring constant of the elastic bodies 11, 12 differs in the circumferential direction. Friction is increased in a region in which the number of revolutions of the inner and outer rings 7, 9 is small and is reduced in a region other than the region in which the number of revolutions is small. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a one-way clutch used, for example, in a stator of a transmission mechanism of an automobile.

  In a torque converter used as a speed change mechanism of an automobile, as shown in FIG. 9, a turbine impeller 101 is rotated by an output shaft 100 driven from the engine side, and an ATF (automatic transmission oil) is used as a turbine runner. The rotating torque of the turbine runner 102 is increased via the stator 103 and the power is transmitted to the input shaft 104 of the transmission. A one-way clutch 105 is attached to the stator 103, and the inner ring 106 is non-rotatably disposed on a fixed shaft 107 disposed around the input shaft 104 by spline fitting or the like.

  FIG. 10 is a partial cross-sectional view in the axial direction showing a configuration example of the stator 103 and the one-way clutch 105 incorporated in the stator 103. An outer ring 109 is fitted on the boss portion 108 of the stator 103, the inner ring 106 is disposed on the fixed shaft 107 so as not to be rotatable by a spline or the like, and a sprag (engaging member) 110 is provided between the outer ring 109 and the inner ring 106. They are arranged at predetermined intervals in the direction. A retainer (bearing support) 111 is fitted on both sides between the outer ring 109 and the inner ring 106, fixed by a snap ring 112, and a thrust bearing 113 is disposed on the outside thereof.

  As shown in FIG. 11, the one-way clutch 105 includes a sprag 110, an outer holder 114 that holds the outer part of the sprag 110, an inner holder 115 that holds the inner part of the sprag 110, and the sprag 110 in the circumferential direction. And a ribbon spring 116 urging in one direction (see Patent Document 1).

Note that the one-way clutch is not limited to the one in which the sprag 110 is held by the outer cage 114 and the inner cage 115 as described above. For example, as shown in Patent Document 2, the one-way clutch is arranged on the inner diameter side of a single cage. In some cases, the spring is disposed along the cage, and a sprag is fitted into the cage and the pocket of the spring, and the cage is press-fitted into the inner peripheral surface of the outer ring.
JP 2002-317829 A JP 2003-21174 A

  In general, the one-way clutch 105 used for the stator of the transmission mechanism of an automobile is a region where the rotational speed is small when the engine starts to be driven, and the sprag 110 is engaged with the outer ring 109 and the inner ring 106, and the outer ring 109 does not rotate. When the engine speed increases, the one-way clutch 105 starts to rotate in the idling direction due to the flow of oil in the torque converter. Since the sprag 110 is urged in the meshing direction by the ribbon spring 116, the friction (the drag torque) increases as the rotational speed decreases, and the friction decreases as the rotational speed increases, thereby improving fuel efficiency. That is, as the rotational speed increases, the sprags lift from the inner ring raceway due to centrifugal force, and when the rotational speed exceeds a predetermined rotational speed, the friction is theoretically zero.

  In addition, by setting the spring constant of the ribbon spring 116 that urges the sprag 110 small, the friction is reduced as a whole regardless of the rotational speed, and the fuel consumption can be improved. However, if the friction is reduced, the sprag 110 is not sufficiently engaged with the outer ring 109 and the inner ring 106 in a region where the rotational speed at the start of driving is small, and slip occurs between the sprag 110 and the inner and outer rings 106, 109. There was a problem that defects occurred.

  Accordingly, an object of the present invention is to solve the problem of improving the fuel consumption by reducing the friction while preventing the occurrence of poor meshing in the region where the rotational speed is small.

  The present invention provides a sprag type one-way clutch that transmits or interrupts the rotational power of one of the inner ring and the outer ring to the other, an annular retainer having a plurality of pockets in the circumferential direction, and each of the pockets. And a plurality of elastic bodies that urge each of the sprags in a direction to be engaged with the inner ring and the outer ring, and the spring constants of the elastic bodies are different in the circumferential direction. This is characterized in that the friction is increased in the region where the rotation speed of the wheel is small and the friction is reduced in the region other than the region where the rotation speed is low.

  Specific examples of the method for making the spring constants different in the circumferential direction include the following configurations.

  An annular spring having a plurality of pockets in which the sprags are housed and having a tongue piece as an elastic body projecting the sprags on the inner periphery of each pocket is concentric with the retainer. The length of the tongue piece is changed.

  A pressed steel plate having a plurality of pockets in which the sprags are accommodated, and a tongue piece serving as the elastic body that urges the sprags on the inner periphery of each of the pockets, It is wound to form an annular spring and arranged concentrically with the cage.

  An annular spring having a plurality of pockets in which the sprags are housed and having a tongue piece as an elastic body projecting the sprags on the inner periphery of each pocket is concentric with the retainer. And are partially quenched in the circumferential direction of the spring.

  According to the one-way clutch of the present invention, since the friction is increased in the region where the rotational speed of the inner and outer rings is small, it is possible to prevent the occurrence of poor meshing in the region where the rotational speed is low, and in regions other than the region where the rotational speed is small. Since the friction is reduced, the fuel consumption can be improved.

  According to the present invention, it is possible to reduce friction and improve fuel efficiency while preventing occurrence of poor meshing in a region where the rotational speed is small.

  The best embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a partial cross-sectional view of a one-way clutch, FIG. 2 is a cross-sectional view showing how the one-way clutch is assembled, FIG. 3 is a perspective view of a spring of the one-way clutch, and FIGS.

  Note that the one-way clutch of this embodiment is mainly used in the torque converter shown in FIG.

  As shown in FIGS. 1 to 3, the one-way clutch 1 includes a cage 13, a plurality of sprags 4, and a spring 5.

  The cage 13 is formed in an annular shape made of metal or synthetic resin, and has a plurality of pockets 14 at predetermined intervals in the circumferential direction. The cage 13 has a flange 15 that extends radially outward at one side edge, and is fitted into the outer ring 7 of the stator of the torque converter, for example.

  Each sprag 4 is housed and held in the pocket 14 of the cage 13.

  The spring 5 is formed in an annular shape made of a pressed steel plate, is concentrically arranged along the inner diameter side of the cage 13, and biases each sprag 4 in a direction in which the inner ring 9 and the outer ring 7 are engaged. That is, a plurality of pockets 10 are formed in the spring 5 at predetermined intervals in the circumferential direction, and tongue pieces 11 that are elastic bodies protrude from the inner periphery of each pocket 10. The sprag 4 is accommodated in the pocket 10 and is urged by the tongue piece 11 in a direction to be engaged with the inner ring 9 and the outer ring 7.

  In addition, the spring 5 is formed with a tongue piece 12 that is a longer elastic body than the other tongue pieces 11 in a part in the circumferential direction. The long tongue pieces 12 are smaller in number than the short tongue pieces 11 and are arranged in one place in the circumferential direction. The long tongue piece 12 has a larger force to press the sprag 4 than the short tongue piece 11, and thus the spring constant is different in the circumferential direction by changing the length of the tongue pieces 11 and 12. become.

  By disposing the one-way clutch 1 configured as described above between the inner and outer wheels 7 and 9, the drive of the engine can be transmitted to the input shaft of the transmission, or the transmission can be interrupted.

  Next, the effect | action in the one-way clutch 1 of this embodiment is demonstrated using FIG. In each graph, the vertical axis represents the friction and the horizontal axis represents the outer ring rotational speed.

  FIG. 4A shows a short tongue piece 11. If the tongue piece is short, the force for pressing the sprag 4 is small, but the number of the tongue pieces 11 is large, so that the friction becomes large as a whole. However, since the tongue piece 11 is short, when the outer ring rotational speed increases, the tongue piece 11 is lifted from the inner ring 9 by centrifugal force, and the friction becomes zero early.

  FIG. 4B relates to the long tongue piece 12. If the tongue piece is long, the force for pressing the sprag 4 is large, but since the number of the tongue pieces 12 is small, the friction becomes small as a whole. However, since the tongue piece 12 is long, it takes time for all the tongue pieces 12 to lift from the inner ring 9 even if the outer ring rotational speed increases, and the state in which the friction is small continues for a long time.

  As described above, the spring 5 has two different types of spring constants shown in FIGS. 4A and 4B, and these two types of different spring constants are overlapped, as shown in FIG. In addition, a graph showing the relationship between the friction of the one-way clutch 1 and the outer ring rotational speed is obtained.

  FIG. 5 compares the one-way clutch 1 of the present embodiment with the one-way clutch of the conventional example. In the figure, A is a one-way clutch 1 of this embodiment, and B is a conventional one-way clutch. From FIG. 5, it can be seen that the one-way clutch 1 of the present embodiment has a larger friction in the region C where the outer ring rotation speed is smaller, and a smaller friction in the other region D than in the conventional example.

  According to the one-way clutch 1 configured as described above, since the friction is increased in the region where the rotational speed of the outer ring 7 is small, it is possible to prevent the occurrence of poor meshing in the region where the rotational speed is small and the region where the rotational speed is small. Since the friction is reduced in the other areas, the fuel consumption can be improved.

  Another embodiment of the present invention will be described with reference to FIG.

  FIG. 6 shows a partial cross-sectional view of the one-way clutch. The one-way clutch 1 includes an outer cage 2, an inner cage 3, a plurality of sprags 4, and a spring 5.

  The outer cage 2 is formed in an annular shape made of synthetic resin and has a plurality of pockets 6 at predetermined intervals in the circumferential direction. The outer cage 2 is fitted into an outer ring 7 of a torque converter stator, for example.

  The inner cage 3 is formed in an annular shape made of synthetic resin and has a plurality of pockets 8 at predetermined intervals in the circumferential direction. For example, the inner cage 3 is fitted on an inner ring 9 fitted to the input shaft of the transmission.

  Each sprag 4 is accommodated in the pocket 6 of the outer cage 2 to hold the outer side, and is accommodated in the pocket 8 of the inner cage 3 to hold the inner side.

  The spring 5 is configured in the same manner as in the example shown in FIG. 3, and is concentrically disposed between the outer cage 2 and the inner cage 3, so that each sprag 4 is engaged with the inner ring 9 and the outer ring 7. Energized in the direction.

  Also in the one-way clutch 1 configured in this way, it is possible to prevent the occurrence of meshing failure and to improve fuel consumption.

  Still another embodiment of the present invention will be described with reference to FIG.

  FIG. 7 is a partial side view of the spring 5 of the one-way clutch. The configuration of the one-way clutch other than the spring 5 is the same as the example shown in FIG.

  The present embodiment is characterized in that the spring 5 is formed by winding both ends of a belt-shaped press steel plate in an overlapping manner. That is, as shown in FIG. 7, a band-shaped press steel plate formed with pockets and tongue pieces 11 is formed, and both ends 5a and 5b are overlapped and joined together by welding or the like, or simply overlapped and held. An annular spring 5 is formed by assembling on the inner peripheral surface side.

  The overlapping portion of the spring 5 is harder than other portions. That is, the spring constant of the overlapping portion is large, and the spring constant is small in portions other than the overlapping portion. In addition, the overlap portion has a smaller range in the circumferential direction than portions other than the overlap portion. Thus, in the circumferential direction, a region having a large spring constant and a region having a small spring constant are formed, and a region having a large spring constant is made smaller than a region having a small spring constant. As a result, the relationship between the friction in the overlapping portion and the outer ring rotational speed is as shown in FIG. 4B, and the portion other than the overlapping is as shown in FIG. 4A. The spring 5 having the characteristics shown in (c) is obtained.

  Also in the one-way clutch 1 configured in this way, it is possible to prevent the occurrence of meshing failure and to improve fuel consumption.

  In addition, you may apply the spring 5 which formed the overlap part shown in FIG. 7 to the one-way clutch provided with the inner and outer holder | retainer shown in FIG.

  Still another embodiment of the present invention will be described with reference to FIG.

  FIG. 8 shows a partial cross-sectional view of the one-way clutch. The one-way clutch 1 includes a cage 13, a plurality of sprags 4, and tongue-like elastic bodies 16 and 17.

  The tongue-like elastic bodies 16, 17 are provided with a base fixed to the inner periphery of the pocket 14 of the cage 13, and are attached in a direction to bite the sprags 4 accommodated in the pocket 14 into the inner ring 9 and the outer ring 7. It is fast. The tongue-like elastic body 17 is longer than the tongue-like elastic body 16 and has a large force for pressing the sprag 4. The number of the tongue-like elastic bodies 17 is smaller than that of the tongue-like elastic bodies 16, and the friction is reduced as a whole.

  Also in the one-way clutch 1 configured in this way, it is possible to prevent the occurrence of meshing failure and to improve fuel consumption.

  The method of increasing the friction in a region where the spring constant is different in the circumferential direction, the outer ring rotational speed is small, and reducing the friction in a region other than the region where the rotational number is small is not limited to the configuration of the above embodiment. Absent.

  For example, it may be partially hardened in the circumferential direction of a spring having a tongue for pressing the sprag. That is, by hardening a steel plate spring, its hardness increases and the spring constant also increases. Moreover, the part which quenches makes the range in the circumferential direction small compared with the part which does not quench. Thus, in the circumferential direction of the spring 5, a region having a large spring constant and a region having a small spring constant are formed, and the region having a large spring constant is made smaller than the region having a small spring constant, as shown in FIG. A spring with such characteristics can be obtained.

  Further, the one-way clutch of each of the above embodiments may be applied to a bearing that is an inner ring rotation and transmits the rotation of the inner ring to the outer ring.

  In the one-way clutch of each of the above embodiments, the elastic body having a large spring constant is arranged in one place in the circumferential direction, but may be arranged apart in the circumferential direction, for example.

  Further, the one-way clutch in each of the above embodiments is provided with an elastic body having two different spring constants as shown in FIG. 4, but has an elastic body having three or more different spring constants. As a result, it is sufficient if the torque is large in a region where the rotational speed of the inner and outer rings is small and the torque is small in a region other than the region where the rotational speed is small.

  The present invention is useful as a one-way clutch used in a stator of a torque converter used as a transmission mechanism of an automobile.

The fragmentary sectional view of the one way clutch in an embodiment of the invention Sectional drawing which shows the mode of the incorporation of the one-way clutch in embodiment of this invention The perspective view of the spring of the one-way clutch in embodiment of this invention Action explanatory drawing in an embodiment of the invention Action explanatory drawing in an embodiment of the invention The fragmentary sectional view of the one way clutch in other embodiments of the present invention The partial side view of the spring of the one way clutch in other embodiment of this invention The fragmentary sectional view of the one way clutch in other embodiments of the present invention. Partial sectional view in the axial direction of a torque converter used as a speed change mechanism of an automobile Partial sectional view in the axial direction of a stator incorporating a conventional one-way clutch Side view of a conventional one-way clutch incorporated in a stator

Explanation of symbols

1 One-way clutch 4 Sprag 5 Spring 10, 14 Pocket 7 Outer ring 9 Inner ring 11, 12 Tongue piece (elastic body)
13 Cage

Claims (2)

In the sprag type one-way clutch that transmits or blocks the rotational power of one of the inner ring and the outer ring to the other,
An annular retainer having a plurality of pockets in the circumferential direction, a plurality of sprags held in the respective pockets, and a plurality of elasticity for urging the sprags in a direction in which the inner and outer rings are engaged. With body,
A one-way clutch characterized in that a spring constant of the elastic body is different in a circumferential direction, the friction is increased in a region where the rotational speed of the inner and outer rings is small, and the friction is reduced in a region other than the region where the rotational speed is small. .   2. The one-way clutch according to claim 1, wherein the one-way clutch includes a range in which the spring constant of the elastic body is large and a range in a circumferential direction, and a range in which the spring constant is large is smaller than a range in which the spring constant is small.

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