JP4048414B2 - One way clutch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a one-way clutch used for a starter or the like.
[0002]
[Prior art]
When the driving force is temporarily transmitted from the driving shaft to the driven shaft, if the driven shaft rotates relative to the driving shaft, the one-way clutch is used to smoothly disconnect the driving force between the two shafts. Is often used. Such a one-way clutch is used in various power transmission devices such as an automatic transmission and an engine starter.
There are various types of this one-way clutch, but a typical one is provided with a sprag between an outer race (outer ring) and an inner race (inner ring). Such a one-way clutch is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 11-141575, 11-201195, and 2001-99197.
[0003]
[Problems to be solved by the invention]
However, in the case of the one-way clutch disclosed in the above publication, etc., the sprag used therein is a part that has a special shape and requires precise machining in terms of its function. For this reason, the manufacture of sprags is a high cost factor.
Further, since the sprag does not roll like a ball, the one-way clutch using the sprag needs to be housed in an oil-tight case and used in a situation where the lubricating oil is abundant. If this one-way clutch is grease-lubricated and used in a release atmosphere, functional failure may occur due to poor lubrication or high viscosity of the grease at low temperatures due to reduced sprag operability.
The present invention has been made in view of such circumstances. That is, an object of the present invention is to provide a one-way clutch that can be used in various environments at a low cost and is based on a mechanism that is completely different from a conventional one-way clutch.
[0004]
[Means for Solving the Problems]
Therefore, the present inventor has intensively studied to solve this problem, and as a result of repeated trial and error, the inventors have come up with the idea of using balls instead of sprags and using plates instead of inner and outer rings, and have completed the present invention. It was.
That is, the one-way clutch of the present invention extends from the inner circumferential side of the first circular groove and the first circumferential groove in an oblique direction to the radial direction, and the groove depth is shallow from the inner peripheral part to the outer peripheral part. A first clutch plate having a first crack surface including a first guide groove communicating with the first circulation groove at the outer periphery, and a circular second provided opposite to the first circulation groove. A second groove comprising a circumferential groove and a second guiding groove provided corresponding to the first guiding groove and extending radially from the inner circumferential side of the second circumferential groove and communicating with the second circumferential groove at the outer circumferential portion; At least one of the first clutch plate and the second clutch plate in a direction in which the second clutch plate having a crack surface and the first crack surface and the second crack surface disposed opposite to each other are brought close to each other. first clutch plate and the second Kuratchipu with one of the elastically biases Urging moving means for allowing the movement to at least one axis direction and over bets, allow traffic between the first circumferential groove and said second circumferential groove and the first guide grooves and second guide grooves And a ball sandwiched between the first clutch plate and the second clutch plate,
When the ball is between the opposing first guide groove and the second guide groove, the first clutch plate and the second clutch plate rotate integrally through the ball, and the ball When the ball is between the opposed first and second circumferential grooves, the ball rolls to allow relative rotation between the first and second clutch plates. To do.
[0005]
The one-way clutch of the present invention uses a ball as a rolling element as a power transmission. For this reason, for example, even when the one-way clutch is used in a release atmosphere with grease lubrication, stable operation of the one-way clutch can be ensured. In addition, even if the ball is highly accurate, it can be obtained at a low cost, so it is easy to reduce the cost of the one-way clutch. Each clutch plate can of course be manufactured by cutting, but can also be manufactured at low cost by die forging or the like, and similarly, the cost of the one-way clutch can be reduced.
Next, the operation of the one-way clutch according to the present invention will be described. Here, for convenience of explanation, as an example, a case will be described in which the first clutch plate is the driving side and the second clutch plate is the driven side, and power is temporarily transmitted from the first clutch plate to the second clutch plate.
First, consider a state where the first clutch plate and the second clutch plate are stationary. At this time, the ball was sandwiched between the first guide groove and the second guide groove facing each other by the first clutch plate and the second clutch plate urged in the proximity direction by the urging and moving means. It becomes a state. In addition, since the first guide groove has a deep groove depth from the outer peripheral portion to the inner peripheral portion, and the urging force of the urging / moving means acts on the ball there, the ball has the deepest depth of the first guide groove. It will be in the state held by the part.
Next, when the first clutch plate starts rotating from this state, the rotational force is applied from the first clutch plate to the second clutch plate via a ball sandwiched between the first guide groove and the second guide groove. Is transmitted, and the second clutch plate starts rotating. At this time, the centrifugal force acting on the ball also increases with an increase in the rotational speed of both. When this centrifugal force increases to some extent, the ball starts moving on the first guide groove from the inner peripheral portion toward the outer peripheral portion by the component force in the first guide groove direction. The movement of the ball on the first guide groove is determined by the inclination angle of the first guide groove with respect to the radial direction, the degree of change (inclination) of the groove depth from the inner periphery to the outer periphery, and the biasing movement means. It is determined by the power.
[0006]
Further, when the rotation speeds of the first clutch plate and the second clutch plate are increased and the second clutch plate starts to rotate at a higher speed than the first clutch plate, the ball resists the urging force of the urging moving means. Then, while increasing the distance between the first clutch plate and the second clutch plate, the transition from the first guide groove and the second guide groove to the first turn groove and the second turn groove starts. When the transition of the ball to the first circulation groove and the second circulation groove is completed, the ball only rolls between the first circulation groove and the second circulation groove. Then, the first clutch plate and the second clutch plate are allowed to rotate relative to each other as if a thrust bearing is interposed, and the power transmission between them is cut off.
Conversely, when the rotational speed of the first clutch plate decreases from this state and the relative rotation between the first clutch plate and the second clutch plate disappears, the ball is moved from the first circulation groove and the second circulation groove to the first. Guided to the guide groove and the second guide groove. Then, the ball settles on the inner peripheral portion (the deepest portion) of the first guide groove. Thereafter, only the above-described operation is repeated.
[0007]
Here, in order to reliably return the ball from the first circumferential groove or the like to the first guide groove or the like, it is necessary to appropriately set an oblique condition (tilt condition) with respect to the radial direction of the first guide groove. In particular, with respect to the tilting direction, for example, when the first clutch plate is on the drive side, the first guide groove may be tilted toward the rotational direction with respect to the radial direction. Conversely, if the first clutch plate is on the driven side, the direction in which the first guide groove is inclined may be on the side opposite to the rotational direction with respect to the radial direction.
Further, a plate-like retainer comprising a long hole extending in the radial direction and holding the ball corresponding to the first guide groove and the second guide groove is disposed between the first clutch plate and the second clutch plate. It is preferable. Thereby, even when the balls are rolling in the first circulation groove and the second circulation groove, the interval (pitch) is kept constant. For this reason, after that, all the balls can be surely and stably returned from the first circumferential groove and the second circumferential groove to the first guiding groove and the second guiding groove.
Further, from the viewpoint of improving the returnability of the ball, the outermost circumference circle diameter enveloping the outermost end of the first guide groove is preferably larger than the center circle diameter of the first circulation groove.
Theoretically, the one-way clutch can operate even with one or two first guide grooves, second guide grooves, and balls. However, from the viewpoint of ensuring the uniformity of the rotating body and the stable operation of the one-way clutch due to the dispersion of power transmission, etc., the first guide groove and the second guide groove are equally distributed at three or more locations on each clutch surface. It is preferable to be provided. Of course, the number of balls is also combined with these numbers.
[0008]
Until now, the case where the first clutch plate is the drive side has been mainly described, but the second clutch plate may be the drive side. Moreover, although the groove depth of the 1st guide groove is made shallow toward an outer peripheral part from an inner peripheral part, you may perform the same thing with respect to a 2nd guide groove. Each groove may have a square or circular cross section.
In addition, the urging force by the urging / moving means is sufficient to urge either the first clutch plate or the second clutch plate to the other so that the crack surfaces face each other. It may be energized. The movement permitted by the biasing movement means is generally an axial slide.
Such a one-way clutch can be used stably in both lubrication with lubricating oil and lubrication with grease, so that it can be used in either a sealed atmosphere or an open atmosphere. For example, it can be used for an automatic transmission (AT), a starter and the like. Recently, an engine automatic stop / start system has attracted attention from the viewpoints of environmental problems and fuel consumption reduction. The one-way clutch for the restart device is particularly effective.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to embodiments.
FIG. 1 shows an entire restart device RS for an automatic engine stop / start system using a one-way clutch W according to an embodiment of the present invention.
As shown in FIG. 2, the restart device RS is attached to the front side of the engine E separately from a normal starter S attached for starting. Then, the engine E and the restart device RS are driven by a power transmission belt B suspended between a crank pulley CP attached to the crankshaft of the engine E and a restart pulley P attached to the output shaft O of the restart device RS. Power is transmitted to and from. Then, the restart device RS smoothly restarts the engine E when the vehicle starts after idling stop of the engine E except for the start at the time of initial cooling.
[0010]
By the way, the restart device RS has a reduction gear G composed of a motor M as a driving source and a set of planetary gears that decelerates and outputs an input received from the motor shaft Ms, and outputs the reduction gear G to an output shaft O. And the one-way clutch W that temporarily transmits to the restart pulley P described above. These connection relationships are shown in FIG.
The motor M used here is a direct current machine that operates on battery voltage, and is controlled by a control device (ECU) dedicated to the restart device RS. Incidentally, this ECU performs transmission / reception with the engine ECU and the brake ECU, and controls the motor M in conjunction with the operating state of the engine, the brake operation state of the driver, and the like.
[0011]
The driving force generated by the motor M is input to the speed reducer G via the motor shaft Ms. The reduction gear G includes a sun gear Gs, a fixed ring gear Gr that surrounds the outer periphery thereof, three planetary gears Gp that mesh with both and rotate around the sun gear Gs, and these planetary gears Gp. The carrier pin Gc is supported and coupled via a first clutch plate 10 described later. Thus, the sun gear input from the motor M is decelerated to become a carrier output, and is output from the reduction gear G to the one-way clutch W.
[0012]
The one-way clutch W includes a first clutch plate 10, a second clutch plate 20, a retainer 30 sandwiched therebetween, a retainer 30, and a first clutch plate 10 and a second clutch plate 20. The sandwiched ball 50 includes an urging movement means 40 that urges the second clutch plate 20 to the first clutch plate 10 and allows sliding in the axial direction. Needless to say, the first clutch plate 10 is a driving side in the present invention, and the second clutch plate 20 is a driven side in the present invention. Next, each component of these one-way clutch W will be described in detail.
[0013]
First, the first clutch surface side of the first clutch plate 10 is shown in FIG.
The first clutch plate 10 is made of a metal disk and has three through holes 13 that are equally drilled in the center. The carrier pin Gc is press-fitted and fixed in the through hole 13, and the three planetary gears Gp supported by the carrier pin Gc rotate together with the first clutch plate 10.
The first clutch plate 10 has a first circumferential groove 11 and a first guide groove 12 on one surface (first clutch surface). The first circumferential groove 11 is a circular continuous groove provided on the outer circumferential side of the first clutch plate 10. This groove | channel is a shallow groove | channel with a cross-sectional square shape and constant depth so that FIG. 8 which is AA cross section shown in FIG. 4 may also show.
[0014]
The first guide groove 12 is an oval groove extending in an oblique direction (attack angle α direction) with respect to the radial direction. Further, as can be seen from FIG. 8, the first guide groove 12 is a groove having a semicircular cross section. The outer peripheral portion 12 a communicates with the first circular groove 11 and the bottom surface of the outer peripheral portion 12 a is the first circular. It is smoothly connected to the bottom surface of the groove 11. The groove depth increases from the outer peripheral portion 12a to the inner peripheral portion 12b at a constant rate (inclination angle β). In the present embodiment, eight first guide grooves 12 are equally arranged per first clutch plate 10. In addition, the arrow in FIG. 4 shows a rotation direction.
[0015]
Next, the second clutch surface side of the second clutch plate 20 is shown in FIG.
The second clutch plate 20 is also made of a metal disk, and has a second circulation groove 21 and a second guide groove 22 on one surface (second clutch surface). Similar to the first circumferential groove 11, the second circumferential groove 21 is a circular continuous groove provided on the outer circumferential side of the second clutch plate 20. Moreover, it has the same cross-sectional square shape as the 1st surrounding groove 11 so that FIG. 8 may show.
[0016]
The second guide groove 22 is also a groove having a semicircular cross section similar to the first guide groove 12. However, unlike the first guide groove 12, the first guide groove 12 extends as it is without inclining in the radial direction, and has a substantially U shape that communicates with the second circumferential groove 21 at its outer peripheral portion 22 a. Further, the groove depth from the outer peripheral portion 22 a to the inner peripheral portion 22 b is constant and equal to the groove depth of the second circumferential groove 21.
The second clutch plate 20 has a center hole 23 drilled in the center thereof and slide holes 24 drilled equally on both sides thereof, which will be described later.
[0017]
Next, a plan view of the retainer 30 is shown in FIG.
The retainer 30 has a ring shape made of a thin metal disk, and is provided with a long hole 32 penetrating therearound. In FIG. 5, the state in which the ball 50 is held in the elongated hole 32 is also shown for reference.
The first clutch plate 10, the second clutch plate 20, and the retainer 30 described above all have the same outer diameter. When they are arranged concentrically as shown in FIG. 3, the first circumferential groove 11 and the second circumferential groove 21 face each other, and the first guiding groove 12 and the second guiding groove 22 are also elongated holes. 32 to face each other. FIG. 7 shows an example of the overlapping state of the grooves on both crack surfaces when the first clutch plate 10 and the second clutch plate 20 are stationary.
[0018]
By the way, in this embodiment, although the 1st guide groove 12, the 2nd guide groove 22, and the elongate hole 32 were each equally distributed and arrange | positioned at eight places of circumferential shape, the operation | movement of the one-way clutch W is so that this number is large. Smooth. Of course, if there are restrictions on dimensions, strength, etc., the number may be reduced, for example, three or four. Needless to say, the balls 50 are made of steel balls, the number of which is the same as the number of the grooves. Of course, theoretically, the one-way clutch can operate even if the number of balls is smaller than the number of grooves, but in order to obtain an efficient and stable operation, it is preferable that the number be the same.
[0019]
Next, the biasing movement means 40 will be described with reference to FIGS. 3 and 5.
The biasing movement means 40 includes a base plate 41 formed integrally with the output shaft O, a center pin 43 protruding from the center of the base plate 41 toward the one-way clutch W, and press-fitted into the base plate 41 on both sides of the center pin 43. It consists of a fixed slide pin 44 and a ring-shaped disc spring 42 mounted around the center pin 43. The center pin 43 is slidably fitted into the center hole 23 of the second clutch plate 20 described above, and the two slide pins 44 are slidably fitted into the two slide holes 24, respectively. The disc spring 42 urges the second clutch plate 20 toward the first clutch plate 10 by using the base plate 41 whose movement in the axial direction is restricted as a spring seat.
[0020]
Thus, the second clutch plate 20 is concentric with the base plate 41 by the fitting of the center hole 23 and the center pin 43. Further, the second clutch plate 20 is guided to the center pin 43 and the slide pin 44 through the center hole 23 and the slide hole 24, and can move in the axial direction while resisting the biasing force of the disc spring 42.
The output shaft O integrated with the base plate 41 is supported by a ball bearing Br, and a restart pulley P is screwed to the tip of the output shaft O. The restart pulley P and the second clutch plate 20 rotate integrally with the slide pin 44.
[0021]
Next, the operation of the one-way clutch W will be described.
First, when the engine E and the restart device RS are stopped due to idling stop or the like, the one-way clutch W is naturally stationary. At this time, the ball 50 sandwiched between the first clutch plate 10 and the second clutch plate 20 facing each crack surface is inclined by the bottom surface of the first guide groove 12, so that the disc spring 42 is attached. It is held by the inner peripheral part 12b which is the deepest part by the force.
[0022]
From this state, when the driver releases the brake pedal to start the vehicle, electric power is supplied to the motor M under the control of the ECU. Then, the driving force of the motor M is input to the first clutch plate 10 via the motor shaft Ms and the speed reducer G. At this time, the first clutch plate 10 and the second clutch plate 20 are restrained by a ball 50 sandwiched between the first guide groove 12 and the second guide groove 22, and the relative movement between the two is restricted. . For this reason, the first clutch plate 10 and the second clutch plate 20 rotate integrally, and power is transmitted from the first clutch plate 10 to the second clutch plate 20.
[0023]
At this time, a centrifugal force corresponding to the number of rotations acts on the ball 50 rotating together with the second clutch plate 20. Due to this centrifugal force, the ball 50 starts to rise on the inclined bottom surface of the first guide groove 12 and pushes and slides the second clutch plate 20 against the urging force of the disc spring 42.
When the rotation speed of the second clutch plate 20 further increases and the engine E is restarted, the rotation speed of the second clutch plate 20 exceeds the rotation speed of the first clutch plate 10. Then, the ball 50 that has been rotating together with the first clutch plate 10 and the second clutch plate 20 escapes from the areas of the first guide groove 12 and the second guide groove 22, and the first circulation groove 11 and the second circulation groove 21. Plunge into the area. Then, the ball 50 only receives an axial (thrust direction) load associated with the urging force of the urging / moving means 40 and is not restricted in the circumferential direction at all. As a result, as the second clutch plate 20 rotates, the ball 50 rolls in the areas of the first circumferential groove 11 and the second circumferential groove 21. Thus, the one-way clutch W acts like a thrust bearing, allowing relative rotation between the first clutch plate 10 and the second clutch plate 20, and interrupting power transmission between them. The engine E is restarted smoothly by the action of the one-way clutch W.
[0024]
Next, consider a case where the engine E is stopped from this state by idling stop or the like. At this time, as long as the second clutch plate 20 rotates with respect to the first clutch plate 10, the ball 50 does not return to the areas of the first guide groove 12 and the second guide groove 22. However, when the relative rotational speed of the both becomes substantially zero, the ball 50 is temporarily held in the region of the first circumferential groove 11 and the second circumferential groove 21, or the first guiding groove 12 and the second circumferential groove 21. 2 Return to the area of the guide groove 22 by itself. Even if the ball 50 stays in the region of the first circulation groove 11 and the second circulation groove 21, when the first clutch plate 10 on the driving side is rotated at the next restart of the engine E, the ball 50 is It always automatically returns to the area of the first guide groove 12 and the second guide groove 22. This is because the first guide groove 12 provided on the crack surface of the first clutch plate 10 is inclined in the rotation direction at the angle of attack α, so that the ball with the first guide groove 12 on the first circumferential groove 11 This is because it behaves as if scoring 50. When the balls 50 return to the first circumferential groove 11, all the balls 50 return almost simultaneously due to the presence of the retainer 30.
Thereafter, only the above-described operation is repeated.
[0025]
By the way, in order to improve the return property of the ball 50 to the first guide groove 12 and the like at the time of restart, the outermost circumference circle diameter R1 of the first guide groove 12 is set as shown in FIG. It is preferable that the center circle diameter is not less than R0. In other words, the protrusion amount t of the outer peripheral portion 12a of the first guide groove 12 to the first circumferential groove 11 is preferably set to be ½ or more of the width w of the first circumferential groove 11.
[0026]
In the above, the case where the one-way clutch of the present invention is used for the restart device RS for the engine automatic stop / start system has been described. Can do.
[0027]
【The invention's effect】
Since the one-way clutch of the present invention has a simple structure using balls that are rolling elements, its application range is wide. For example, grease can be lubricated and the one-way clutch can be used in an open atmosphere.
[Brief description of the drawings]
FIG. 1 is a half sectional view showing a restart device according to an embodiment of the present invention.
FIG. 2 is a schematic view showing a state in which the restart device is attached to a vehicle.
FIG. 3 is a cross-sectional view showing a one-way clutch used therefor.
FIG. 4 is a plan view showing a first clutch plate of the one-way clutch.
FIG. 5 is a plan view showing a second clutch plate of the one-way clutch.
FIG. 6 is a plan view showing a retainer of the one-way clutch.
FIG. 7 is a view showing the positions of the grooves when the crack surfaces of the first clutch plate and the second clutch plate are overlapped in a stationary state.
8 is a partial cross-sectional view of the assembled one-way clutch when cut at the position AA in FIG. 4;
FIG. 9 is a plan view showing a more preferable form of the first guide groove in the first clutch plate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 1st clutch plate 20 2nd clutch plate 11 1st circumference groove 12 1st guide groove 21 2nd circumference groove 22 2nd guide groove 40 Energizing moving means 50 Ball W One-way clutch RS Restart device

Claims (6)

The circular first circumferential groove and the first circumferential groove extend obliquely from the inner circumferential side of the first circumferential groove in the radial direction, and the groove depth becomes shallower from the inner circumferential portion to the outer circumferential portion, and the first circumferential loop is formed at the outer circumferential portion. A first clutch plate having a first crack surface comprising a first guide groove communicating with the groove;
A circular second circumferential groove provided opposite to the first circumferential groove and a radial direction extending from the inner circumferential side of the second circumferential groove provided in correspondence with the first guiding groove, The second clutch plate having a second crack surface comprising a second guide groove communicating with the second circumferential groove;
At least one of the first clutch plate and the second clutch plate is elastically urged in a direction in which the first crack surface and the second crack surface disposed to face each other are brought close to each other , and the first clutch plate And an urging movement means for allowing movement in the axial direction of at least one of the second clutch plate,
A ball sandwiched between the first clutch plate and the second clutch plate so as to be able to travel between the first circulation groove and the second circulation groove and the first guide groove and the second guide groove; ,
When the ball is between the opposing first guide groove and the second guide groove, the first clutch plate and the second clutch plate rotate integrally through the ball, and the ball When the ball is between the opposed first and second circumferential grooves, the ball rolls to allow relative rotation between the first and second clutch plates. One way clutch to do. The one-way clutch according to claim 1, wherein the first guide groove and the second guide groove are equally provided at three or more locations. Further, a long hole that is disposed between the first clutch plate and the second clutch plate and extends in a radial direction corresponding to the first guide groove and the second guide groove and holds the ball. The one-way clutch according to claim 1, further comprising a plate-like retainer. 2. The one-way clutch according to claim 1, wherein an outermost circumferential circle diameter enveloping an outermost end of the first guide groove is larger than a central circle diameter of the first circumferential groove. The first clutch plate is on the drive side ;
The second clutch plate is driven side,
The one-way clutch according to claim 1, wherein the first guide groove is inclined toward the rotational direction with respect to the radial direction. The one-way clutch according to claim 1, wherein the one-way clutch is used for a starting device for starting an engine.

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