JP5245712B2 - Rotational speed sensitive one-way clutch - Google Patents

Description

  The present invention relates to a rotational speed sensitive one-way clutch, and more particularly to a rotational speed sensitive one-way clutch used for an input shaft of an auxiliary device such as an alternator driven by the power of a crankshaft of an engine. It is.

  In general, a driven pulley is fixed to the end of the rotating shaft of an automobile auxiliary machine such as an alternator, and an endless belt is stretched between the crank pulley fixed to the end of the crankshaft of the engine. Is used to drive. In addition, the driven pulley allows the transmission of power from the endless belt to the rotating shaft when the running speed of the endless belt is constant or increases, and the driven pulley is driven when the running speed of the endless belt tends to decrease. 2. Description of the Related Art A pulley device that incorporates a one-way clutch so as to freely rotate a pulley and a rotation shaft is known. In this way, by incorporating the one-way clutch, belt slip prevention and fuel efficiency are improved.

  The one-way clutch forms a cam surface having a plurality of ramp surfaces on either of the raceway surfaces of the clutch inner ring and the clutch outer ring, thereby forming a plurality of wedge spaces, and an engagement element disposed in the space. However, it is possible to transmit power freely by engaging and disengaging with both raceway surfaces. Further, the engagement element is urged by a spring fixed to the cage in the wedge direction, that is, the engagement element cannot be locked, and is biased toward the narrow side of the wedge space, that is, the shallow side of the ramp surface (for example, Patent Document 1 and 2).

  The one-way clutch described in Patent Document 1 employs an outer ring ramp structure in which a cam surface is formed on the raceway surface of the clutch outer ring, and even if a disturbance such as engine vibration occurs in the idling state by devising the cam surface. The combination and the inner ring of the clutch are configured so as not to contact each other.

Further, in the one-way clutch described in Patent Document 2, in the inner ring ramp structure in which the cam surface is formed on the raceway surface of the clutch inner ring, the function of the one-way clutch that engages and idles when the rotational speed exceeds a predetermined value. What has been proposed has been proposed. Specifically, by placing a weight on the inner diameter side of the engagement element and moving the weight using centrifugal force, the engagement element is pressed to a position where it can be engaged with the cam surface, thereby transmitting torque. Has been done.
JP 2007-40376 A JP 2004-316890 A

  By the way, in the one-way clutch of the outer ring ramp structure, it is desired to perform the ON / OFF function of the clutch according to the magnitude of the rotational speed. However, the one-way clutch described in Patent Document 2 has the inner ring ramp structure. Therefore, it was difficult to use an outer ring lamp structure. Further, the one-way clutch described in Patent Document 1 does not take into consideration the ON / OFF function of the clutch according to the magnitude of the rotation speed, and has a configuration in which the clutch function is activated immediately after the rotation starts.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a rotational speed-sensitive one-way clutch having an outer ring lamp structure that can switch the ON / OFF function of the clutch when the rotational speed exceeds a predetermined rotational speed. Is to provide.

The above object of the present invention can be achieved by the following constitution.
(1) A clutch inner ring having a cylindrical inner ring raceway surface on the outer peripheral surface, a clutch outer ring having an outer ring raceway surface having a plurality of ramp surfaces formed on the inner peripheral surface, and the inner ring raceway surface and the plurality of ramp surfaces. A plurality of engagement elements respectively disposed in the plurality of wedge spaces, a retainer that holds the plurality of engagement elements, and an elastic member that is retained by the retainer and can bias the engagement elements in the wedge direction. A rotational speed sensitive one-way clutch comprising:
A cage moving mechanism having a weight movable by centrifugal force so as to move the cage ;
Another elastic member held by the cage and capable of urging the engagement element in a direction opposite to the wedge direction;
A rotational speed-sensitive one-way clutch comprising:
(2) The rotational speed sensitive one-way clutch according to (1), wherein the cage moving mechanism moves the cage in a circumferential direction.
( 3 ) The rotational speed-sensitive one-way clutch according to (1) or (2) , wherein the weight and the cage are provided with inclined surfaces that can be opposed to each other.

  According to the rotational speed sensitive one-way clutch of the present invention, since the cage moving mechanism having the weight that can be moved by centrifugal force so as to move the cage is provided, the outer ring of the clutch rotates at a predetermined rotational speed or more. Thus, the cage moves as the weight moves due to centrifugal force. As a result, when the predetermined rotational speed is reached, the engagement element held by the cage moves to a predetermined position between both raceway surfaces so that the engagement and idling operation can be performed, that is, the clutch function. Is turned on.

  Therefore, for example, when the rotational speed at which the clutch function is turned on is designed as the idling rotational speed, the engine is not loaded with the inertia of the auxiliary machine when the engine is started, so the engine can be started with low torque. Therefore, the engine can be started in a short time, the fuel injection amount at the time of starting the engine is small, the fuel efficiency can be improved, the current consumption of the starter can be kept low, and the starter capacity can be reduced. . Further, since the belt tension applied at the time of starting can be kept low, slipping and squealing of the belt can be prevented, and further, the radial load applied to the auxiliary machine can be kept low, which contributes to extending the life of the bearing.

  Hereinafter, a pulley device with a built-in one-way clutch to which a rotation-sensitive one-way clutch of the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a longitudinal sectional view for explaining a pulley device with a built-in one-way clutch for automobile auxiliary equipment according to this embodiment. The one-way clutch built-in pulley apparatus 10 transmits power between an automobile auxiliary machine such as an alternator and a crank pulley fixed to an end portion of an engine crankshaft. As shown in FIG. 1, the pulley apparatus 10 includes a sleeve 11 into which a shaft of an unillustrated automobile auxiliary machine is fitted. Around the sleeve 11, a pulley 12 having a belt groove 12 a formed on the outer peripheral surface is disposed concentrically with the sleeve 11. In addition, a one-way clutch 13 is disposed between the outer peripheral surface of the sleeve 11 and the inner peripheral surface of the pulley 12 in the intermediate portion in the axial direction of the annular space formed therebetween. A pair of support bearings 14a and 14b which are ball bearings, such as a deep groove ball bearing, are arrange | positioned at both ends, ie, the axial direction both sides of the one-way clutch 13, for example. In addition, the shape of the belt groove 12a can be designed in an arbitrary shape such as a V groove, a poly V groove, or a tooth groove.

  The one-way clutch 13 is set so that the clutch function is switched ON / OFF based on a predetermined rotation speed, for example, an idling rotation speed, and the pulley 12 is predetermined with respect to the sleeve 11 in the function ON state. The rotational force from the pulley 12 to the sleeve 11 is transmitted only when there is a tendency to rotate relative to the direction. Further, the pair of support bearings 14 a and 14 b enables relative rotation between the sleeve 11 and the pulley 12 while supporting a radial load applied to the pulley 12.

  Each of the support bearings 14 a and 14 b includes a bearing inner ring 31 fitted on the outer circumferential surface of the sleeve 11, a bearing outer ring 32 fitted on the inner circumferential surface of the pulley 12, and both raceway surfaces of the bearing inner ring 31 and the bearing outer ring 32. A plurality of balls 33 that are rolling elements arranged between them, a bearing cage (not shown) that holds the balls 33 in a freely rolling manner, and foreign substances such as intrusion of foreign matter and grease from the inside. It has a seal member (not shown) for preventing leakage.

  As shown in FIGS. 1 and 2, the one-way clutch 13 includes a clutch inner ring 15 that is press-fitted and fixed to the outer peripheral surface of the sleeve 11, a clutch outer ring 16 that is press-fitted and fixed to the inner peripheral surface of the pulley 12, and a clutch inner ring 15. And a plurality of rollers 20 which are engaging members rotatably arranged between the outer ring 16 and the clutch outer ring 16. The inner peripheral surface of the clutch outer ring 16 forms a cam surface in which a plurality of concave ramp surfaces 16a, which are outer ring raceways with which the rollers 20 are in rolling contact, are provided at predetermined intervals in the circumferential direction. The roller 20 is rotatably held in a plurality of wedge spaces formed by the ramp surfaces 16 a and a cylindrical surface 15 a that is an inner ring raceway surface formed on the inner peripheral surface of the clutch inner ring 15.

  In addition, the one-way clutch 13 is fixed to the clutch inner ring 15 and has a cage 21 having a plurality of pockets for individually holding the rollers 20, and is held by the cage 21. A first spring 22 (see FIG. 2) that is an elastic member that can be urged in a wedge direction to be engaged with the surface and the inner peripheral surface of the clutch outer ring 16, and each roller 20 in a direction opposite to the wedge direction (anti-wedge). 2) between the second spring 23 (see FIG. 2), which is another elastic member that can be biased in the direction), and the inward stepped portion 12b formed on the pulley 12 and the bearing outer ring 32 of the support bearing 14b. And a weight 25 attached to a notch 24a formed in the spacer 24 via a support spring 26. In addition, at least one weight 25 may be provided, but a plurality of weights 25 are preferably arranged symmetrically.

  As shown in FIG. 3, the retainer 21 connects a pair of annular portions 21a and 21b and the annular portions 21a and 21b, and a plurality of column portions arranged at predetermined intervals in the circumferential direction. 21c. The column portion 21c is formed with a pair of upright portions 21d and 21e that rises outward in the radial direction, and sandwiches the base portions 22a and 23a of the first and second springs 22 and 23. Further, the circumferential movement of the cage 21 with respect to the clutch outer ring 16 is permitted to such an extent that the roller 20 moves between the ramp surface 16a and the cylindrical surface 15a and the clutch ON / OFF function is switched. .

  As shown in FIG. 2, each roller 20 is pressed by two opposing first and second springs 22 and 23. The first spring 22 that presses in the wedge direction is for bringing the roller 20 into contact with the ramp surface 16a and the cylindrical surface 15a as in the prior art. Further, the second spring 23 that presses in the anti-wedge direction is balanced with the first spring 22 that biases in the wedge direction in order to turn off the clutch function, holds the roller 20, and the cage 21 is anti-wedge. When moving in the direction, the roller 20 is also moved in the anti-wedge direction.

  As shown in FIGS. 1 and 4, a recess 21 f into which the weight 25 enters is formed in one annular portion 21 b. The weight 25 supported by the notch 24a of the spacer 24 via the support spring 26 is formed in a column shape so as to be able to advance and retreat in the radial direction in the recess 21f. Inclined surfaces 25 a and 21 g that can be opposed to each other and extend in the circumferential direction are provided in the radially inner portion of the weight 25 and the recess 21 f of the cage 21. Thereby, in this embodiment, the concave portion 21f, the weight 25, and the support spring 26 of the cage 21 constitute a cage moving mechanism 27.

  In the cage moving mechanism 27 configured as described above, when the pulley 12 is in a stationary state, the weight 25 is pushed by the support spring 26 and is located at the innermost side. When the pulley 12 rotates, the support spring 26 is compressed with a force proportional to the square of the rotation speed, and the weight 25 moves to the outer diameter side by centrifugal force. Then, the inclined surfaces 25a and 21g change the contact position, and the centrifugal force increased on the weight 25 is transmitted to the inclined surface 21g of the cage 21, and the cage 21 moves in the circumferential direction.

  Further, since the roller 20 is positioned between the ramp surface 16a and the cylindrical surface 15a depending on the position of the retainer 21 that supports the two springs 22 and 23, the retainer 21 and the two springs 22 and 23 are Thus, the movement of the weight 25 and the position of the roller 20 are linked. Specifically, when the weight 25 is located on the innermost side, the inclined surfaces 25a and 21g sufficiently overlap each other and are held by the two springs 22 and 23, as shown by the solid line in FIG. The cage 21 is positioned on the non-locking side so that the roller 20 is not in contact with the ramp surface 16a of the clutch outer ring 16 and the cylindrical surface 15a of the clutch inner ring 15 at the same time (see FIG. 5A). On the other hand, when the weight 25 is located on the outer diameter side, the cage 21 is moved in the circumferential direction so as to reduce the contact area between the inclined surfaces 25a and 21g as shown by the one-dot chain line in FIG. The cage 21 is positioned on the lock side so that the roller 20 is in contact with the ramp surface 16a and the cylindrical surface 15a simultaneously (see FIG. 5B).

  Therefore, in the one-way clutch 13 configured as described above, when the pulley 12 is in a stopped state, the weight 25 is located at the innermost side, and the cage 21 is still circular along the inclined surface 25a of the weight 25. It is not moving in the circumferential direction. Therefore, as described above, the roller 20 is not in contact with the ramp surface 16a of the clutch outer ring 16 and the cylindrical surface 15a of the clutch inner ring 15 at the same time. In this state, power is not transmitted to the clutch inner ring 15 via the roller 20 even when rotational force is input to the clutch outer ring 16. That is, the clutch OFF state in which the one-way clutch 13 is not operated can be maintained (see the section (a) in FIG. 6).

On the other hand, as the rotational speed increases, the weight 25 moves to the outer diameter side due to the centrifugal force, and the cage 21 is pushed by the inclined surface 25a of the weight 25 and moves in the circumferential direction. When the spring force in the wedge direction is satisfied by reaching an arbitrary rotational speed, the roller 20 simultaneously contacts the ramp surface 16a and the cylindrical surface 15a. As a result, the ramp surface 16a and the cylindrical surface 15a of the inner ring 15 of the clutch are in contact with each other at the same time. To communicate.
In this state, the spring force that presses in the wedge direction is larger than the spring force that presses in the anti-wedge direction, so that the state is the same as that of the conventional one-way clutch, and the engagement and idling operations occur as the rotational force varies. The clutch can be turned on (see section (b) in FIG. 6).

  Specifically, when the rotational angular speed of the pulley 12 is faster than the rotational angular speed of the rotating shaft of the automobile accessory, for example, the roller 20 of the one-way clutch 13 is wedged to cause the ramp surface 16a of the clutch inner ring 15 and the clutch outer ring 16 to move. The pulley 12 and the sleeve 11 are incapable of relative rotation (engaged state) by being engaged with the cylindrical surface 15a, and the rotational force of the engine is transmitted to the rotating shaft of the automobile accessory. On the other hand, when the rotational angular velocity of the pulley 12 is slower than the rotational angular velocity of the automobile accessory, the engagement of the roller 20 is released, and the pulley 12 and the sleeve 11 can freely rotate (idle state).

  On the other hand, when the rotational speed decreases and the centrifugal force applied to the weight 25 decreases, the weight 25 is pushed to the inner diameter side by the support spring 26, and the cage 21 moves in the anti-wedge direction using the lower slope 21h as a guide. When the rotation speed becomes lower than an arbitrary rotational speed, the roller 20 is separated from the ramp surface 16a and the cylindrical surface 15a, and the one-way clutch 13 returns to the clutch-off state (see section (c) in FIG. 6).

  As an additional function, the one-way clutch 13 having the ramp surface 16a on the clutch outer ring 16 generally moves the roller 20 to the anti-wedge side by the centrifugal force applied to the roller 20. However, in the above mechanism, the weight 25 Is moved to the outer diameter side with the centrifugal force, and the spring force of the first spring 22 biased in the wedge direction can be strengthened against the movement of the roller 20, so that the roller 20, the ramp surface 16a, and the cylindrical surface can be strengthened. It is possible to maintain the clutch function until high-speed rotation without being insufficient in contact force with 15a.

  As described above, according to the rotational speed sensitive one-way clutch 13 configured as described above, the cage moving mechanism 27 having the weight 25 movable by the centrifugal force so as to move the cage 21 is provided. By rotating the clutch outer ring 15 at a rotational speed or higher, the cage 21 moves along with the movement of the weight 25 due to centrifugal force. As a result, when the predetermined rotational speed is reached, the roller 20 held by the retainer 21 can move to a predetermined position between the both raceway surfaces, whereby engagement and idling operation can be performed. The function is turned on.

  Further, the cage moving mechanism 27 moves the cage 21 in the circumferential direction, and moves the first and second springs 22 and 23 supported by the cage 21, thereby enabling the clutch ON / OFF function. It can be switched easily.

  Furthermore, since the second spring 23 that is held by the cage 21 and can bias the roller 20 in the direction opposite to the wedge direction is further provided, the ON / OFF function of the clutch can be switched more reliably.

  In addition, since the weight 25 and the cage 21 are provided with inclined surfaces 25a and 21g that can be opposed to each other, the movement of the weight 25 due to the centrifugal force can be effectively converted into the movement of the cage 21. .

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.

  The one-way clutch of the present invention may be a roller clutch as in this embodiment, or may be a cam clutch or a sprag clutch. Further, the outer ring or inner ring of the one-way clutch may be separate from the pulley or sleeve as in the present embodiment, and is integrated with the pulley or sleeve, that is, constituted by the inner peripheral surface of the pulley or the outer peripheral surface of the sleeve. May be.

  Further, the pair of support bearings of the present invention may be of a type other than the deep groove ball bearing, or may be a combination of a roller bearing or a ball bearing. Further, the inner ring or the outer ring of the support bearing may be integrated with the pulley or the sleeve, that is, the inner peripheral surface of the pulley or the outer peripheral surface of the sleeve.

1 is a half cross-sectional view of a pulley device with a built-in one-way clutch according to an embodiment of the present invention. It is sectional drawing of the one-way clutch cut along the II-II line of FIG. It is the partial top view which looked at the one way clutch from the inner side of the clutch outer ring. It is an expanded sectional view of the weight part cut along the IV-IV line of FIG. It is sectional drawing of a one way clutch, (a) shows the state of a clutch function OFF, (b) shows the state of a clutch function ON. It is an operation | movement conceptual diagram of a one way clutch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 One-way clutch built-in pulley apparatus 11 Sleeve 12 Pulley 13 One-way clutch 14 Support bearing 15 Clutch inner ring 16 Clutch outer ring 20 Roller (engagement element)
21 Cage 22 First spring (elastic member)
23 Second spring (other elastic member)
25 Weight 26 Support spring 27 Cage moving mechanism

Claims (3)

A clutch inner ring having a cylindrical inner ring raceway surface on the outer peripheral surface, a clutch outer ring having an outer ring raceway surface having a plurality of ramp surfaces formed on the inner peripheral surface, and a plurality constituted by the inner ring raceway surface and the plurality of ramp surfaces. A plurality of engagement elements respectively disposed in the wedge space, a retainer that holds the plurality of engagement elements, and an elastic member that is retained by the retainer and can bias the engagement element in the wedge direction. A rotational speed sensitive one-way clutch,
A cage moving mechanism having a weight movable by centrifugal force so as to move the cage ;
Another elastic member held by the cage and capable of urging the engagement element in a direction opposite to the wedge direction;
A rotational speed-sensitive one-way clutch comprising:   The rotational speed-sensitive one-way clutch according to claim 1, wherein the cage moving mechanism moves the cage in a circumferential direction. 3. The rotational speed sensitive one-way clutch according to claim 1, wherein the weight and the cage are provided with inclined surfaces that can contact each other while facing each other. 4.

Images