JP2007162814A - One-way clutch built-in type pulley device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way clutch which becomes engaged in an abnormal state, and more improve its reliability. <P>SOLUTION: The cam surface 21a of the one-way clutch 13 comprises: first cam surfaces 21b for normally operating the engagement and the disengagement of rollers 22; second cam surfaces 21c which are continuously formed from the first cam surfaces 21b in the engaging direction, and have a wedge angle β smaller than the wedge angle α of the first cam surfaces 21b; and stepped surfaces 21d which are formed between the first cam surfaces 21b and the second cam surfaces 21c so as to widen the radial width of the wedge spaces from the first cam surfaces 21b toward the second cam surfaces 21c. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pulley apparatus with a built-in one-way clutch, and in particular, as an auxiliary machine for an automobile, such as a starter, an alternator, a crank pulley, a compressor, an auxiliary machine driven by a motor at the time of engine idle stop, or an engine start. The present invention relates to a pulley device with a built-in one-way clutch to be used.

  Generally, a driven pulley is fixed to the end of a rotating shaft of an auxiliary machine for automobiles such as an alternator, and an endless belt is stretched between a driving pulley fixed to an end of an engine crankshaft, It is used to drive the machine. 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. Various one-way clutches incorporated in such pulley devices have been devised (for example, see Patent Documents 1 to 5).

  For example, a one-way clutch is known in which a cam surface is formed on one of an outer ring and an inner ring, and rollers are disposed in a wedge space formed between the outer ring and the inner ring. Then, only when the driven pulley tends to rotate relative to the sleeve fixed to the rotating shaft of the auxiliary machine in a predetermined direction by moving the roller in a wedge space so as to be freely disengaged, the sleeve from the driven pulley is moved to the sleeve. Rotation force can be transmitted freely.

  In the one-way clutches described in Patent Documents 1 to 5, a method has been proposed in which fail-safety is ensured by avoiding an excessive load on the engagement element when an abnormality such as an input of excessive torque occurs. In the one-way clutch described in Patent Document 1, a cam surface angle is changed midway, and the wedge angle on the lock side of the wedge space is made larger than the wedge angle on the overrun side.

  In the one-way clutch described in Patent Document 2, a roller escape portion is formed on the cam surface, the roller moves to the escape portion when an excessive torque is input, and the outer ring and the inner ring rotate relative to each other. In the one-way clutch described in Patent Document 3, a cam surface is formed on the inner ring, and the cam surface is formed to have two types of wedge angles in accordance with two types of rollers having different diameters.

In the one-way clutch described in Patent Document 4, when an excessive torque is input, the wedge angle can be changed by elastic deformation when the engaging element bites into the narrow side of the wedge-shaped space in the locked state. Further, a one-way clutch described in Patent Document 5 has been proposed in which the cam surface angle is changed halfway, and the overrun side wedge angle is made larger than the lock side wedge angle.
JP 2000-179589 A JP 2002-349777 A JP 2001-200804 A JP 2003-232385 A JP 2005-114091 A

  By the way, in the one-way clutches described in Patent Documents 1 to 4, when an abnormality such as excessive torque input occurs, idling, that is, by stopping the lock function, power transmission becomes impossible, and the battery is not charged, and a warning lamp is displayed. Lights up and the user confirms the abnormality. This prevents phenomena such as belt flapping and squealing.

  On the other hand, the one-way clutch described in Patent Document 5 is in a coupled state in which the roller is always engaged when an abnormality occurs by changing the wedge angle. Thus, when an abnormality occurs, it has the same function as a solid pulley, and power can be transmitted continuously through the belt.

  In recent years, many alternators having a brake assist function are used, and a brake assist pump is connected to one end of a rotating shaft of the alternator. Since the pump serves as a power source for the brake booster, in such an alternator, in order to improve the reliability of the brake booster, a one-way clutch that is connected when an abnormality occurs is disclosed in Patent Document 5. It is preferable to apply. In such an alternator, it is desired to further improve the reliability of the one-way clutch that is engaged when an abnormality occurs.

  The present invention has been made in view of the circumstances as described above, and an object of the present invention is to provide a one-way clutch that is brought into a coupled state when an abnormality occurs and has further improved reliability.

The above object of the present invention can be achieved by the following constitution.
(1) An inner ring, an outer ring, a cam surface formed on an outer peripheral surface of the inner ring or an inner peripheral surface of the outer ring, a cam surface of the inner ring and an inner peripheral surface of the outer ring, or a cam surface of the outer ring A roller disposed in a wedge space formed between the outer circumference of the inner ring, and
When one of the outer ring and the inner ring rotates relative to the other in a predetermined direction, the roller is engaged in the wedge space, and the outer ring and the inner ring are substantially coupled to each other, and the other driving force Is a one-way clutch that releases the biting in a state where the one driving force is greater than the one driving force,
The cam surface is formed continuously from a first cam surface in which the rollers are normally engaged and released from the engagement, and from the first cam surface in the engagement direction, and a wedge angle of the first cam surface A radial space of the wedge space is formed between the second cam surface having a smaller wedge angle and the first cam surface and the second cam surface from the first cam surface toward the second cam surface. A stepped surface formed to spread,
When the roller is caught on the second cam surface beyond the stepped surface, the one-way clutch is always in a coupled state, and the one-way clutch cannot be released. And one-way clutch.

  According to the one-way clutch of the present invention, the cam surface is formed continuously in the biting direction from the first cam surface and the first cam surface in which the roller is normally bitten and released. The radial spacing of the wedge space from the first cam surface to the second cam surface between the second cam surface having a wedge angle smaller than the wedge angle of one cam surface and the first cam surface and the second cam surface A step surface formed to widen the one-way clutch, when the roller is engaged on the second cam surface beyond the step surface, the one-way clutch is always in a coupled state. The release is impossible.

  As a result, when an abnormality occurs, such as when excessive torque is input, the roller is displaced over the step surface to the second cam surface to reliably engage, stop the clutch function, and make the outer ring and inner ring substantially In addition, the roller can be prevented from returning to the first cam surface again by the step surface after the connection. Therefore, even when an abnormality occurs, the function of transmitting the rotational force of the one-way clutch is ensured, and the function of the device incorporating the one-way clutch can be more reliably maintained, and the reliability of the device can be improved.

  Hereinafter, a pulley apparatus with a built-in one-way clutch to which a one-way clutch is applied as an embodiment of the present invention will be described 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 an alternator according to this embodiment. As shown in FIG. 1, a pulley apparatus 10 with a built-in one-way clutch according to the present embodiment is for driving an alternator (not shown) and a brake assist vacuum pump as auxiliary machines. It has the sleeve 11 in which the rotating shaft S is fitted. Around the sleeve 11, a pulley 12 having a belt groove 12 a having a poly-V groove shape 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 14, which are ball bearings such as deep groove ball bearings, are disposed at both ends, that is, at positions spaced axially with respect to the one-way clutch 13.

  The one-way clutch 13 transmits the rotational force from the pulley 12 to the sleeve 11 only when the pulley 12 tends to rotate relative to the sleeve 11 in a predetermined direction. Further, the pair of support bearings 14 enables the relative rotation between the sleeve 11 and the pulley 12 while supporting a radial load applied to the pulley 12.

  Each support bearing 14 includes a bearing inner ring 15 fitted on the outer peripheral surface of the sleeve 11, a bearing outer ring 16 fitted on the inner peripheral surface of the pulley 12, and both raceway surfaces of the bearing inner ring 15 and the bearing outer ring 16. A plurality of balls 17 that are arranged rolling elements, a bearing holder 18 that holds the balls 17 in a freely rolling manner, and a seal member that prevents the intrusion of foreign matter from the outside and the leakage of a lubricant such as grease from the inside. 19.

  The one-way clutch 13 rotates between an outer ring 20 that is press-fitted and fixed to the inner peripheral surface of the pulley 12, an inner ring 21 that is press-fitted and fixed to the outer peripheral surface of the large-diameter portion of the sleeve 11, and the outer ring 20 and the inner ring 21. A plurality of rollers 22, which are freely arranged engaging members, a cage 23 having a plurality of pockets for individually holding each roller 22, and an outer peripheral surface of the inner ring 21 and an inner peripheral surface of the outer ring 20. And a spring 24 that is an elastic material that is elastically pressed in a direction in which the spring 24 is engaged.

  As shown in FIG. 2, a plurality of concave cam surfaces 21 a with which the rollers 22 are brought into rolling contact are formed on the outer peripheral surface of the inner ring 21 at predetermined intervals in the circumferential direction. The rollers 22 are connected to the cam surfaces 21 a. It is rotatably disposed in a wedge space composed of a cylindrical surface 20 a formed on the inner peripheral surface of the outer ring 20.

  The cam surface 21a is formed in a ramp shape, and includes a first cam surface 21b formed of an arc surface having a radius of curvature Rα that forms a wedge angle α in the operating range a, and a biting direction from the first cam surface 21b (FIG. 2). And a flat second cam surface 21c having a wedge angle β smaller than the wedge angle α of the first cam surface 21b in the operating range b, and the first cam surface 21b and the second cam surface. A small step surface 21d (see FIG. 2B) formed so as to widen the radial interval of the wedge space from the first cam surface 21b toward the second cam surface 21c. Prepare.

  The operating range a of the first cam surface 21b is determined when the roller 22 is normally engaged and the engagement is released in consideration of the roller diameter, the radial clearance of the one-way clutch 13 and the rolling bearing 14. Reference numeral 22 denotes a movable range. On the other hand, the operating range b of the second cam surface 21c is a range in which the roller 22 does not move in a normal state. When an abnormality occurs such as when an excessive torque is input, the roller 22 bites over the step surface 21d. This is the range where the coupling is not released even if it is rotated in the direction of. That is, when the roller 2 is caught on the second cam surface 21c beyond the stepped surface 21d, the clutch function is stopped, the one-way clutch 13 is always in the coupled state, and the one-way clutch 13 is engaged. The release is impossible.

  In the pulley apparatus 10 with a built-in one-way clutch configured as described above, when the rotational angular speed of the pulley 12 is higher than the rotational angular speed of the rotary shaft S of the auxiliary machine, the rollers 22 of the one-way clutch 13 are normal. Due to the wedge action, the outer ring 20 and the inner ring 21 are substantially connected to each other by being engaged with the wedge space between the first cam surface 21 b of the inner ring 21 and the cylindrical surface 20 a of the outer ring 20. As a result, the pulley 12 and the sleeve 11 become relatively unrotatable (locked state), and the rotational force of the engine is transmitted to the rotation shaft S of the auxiliary machine, whereby the rotor of the alternator is driven to rotate and the vacuum pump The rotor also rotates to generate negative pressure.

  On the other hand, when the rotational angular velocity of the pulley 12 is slower than the rotational angular velocity of the auxiliary machine, the engagement of the rollers 22 is released, and the relative rotation between the pulley 12 and the sleeve 11 becomes free (overrun state). This prevents a phenomenon such as belt flapping or squealing when a speed fluctuation or a minute angular speed fluctuation occurs.

  Further, when an abnormality occurs such as when excessive torque is input, the cylindrical surface 20a of the outer ring 20 expands to the dotted line in FIG. 2, and the roller 22 is not caught by the first cam surface 21b but passes the step surface 21d. 2 Moves to the cam surface 21c. Thus, even when normal torque is input to the overrun side, the step surface 21d serves as a stopper, and the rollers 22 do not move while staying on the second cam surface 21c, and power is transmitted in the locked state.

  Therefore, according to the one-way clutch 13 of the present embodiment, the cam surface 21a includes the first cam surface 21b in which the roller 22 is normally engaged and the engagement is released, and the engagement direction from the first cam surface 21b. Between the first cam surface 21b and the second cam surface 21c, the second cam surface 21c having a wedge angle β smaller than the wedge angle α of the first cam surface 21b. A step surface 21d formed so as to widen the radial space of the wedge space from 21b toward the second cam surface 21c, and the roller 22 is caught on the second cam surface 21c beyond the step surface 21d. When this occurs, the one-way clutch 13 is always in the coupled state, and the one-way clutch cannot be released.

  As a result, when an abnormality occurs, such as when an excessive torque is input, the roller 22 is displaced to the second cam surface 21c beyond the step surface 21d to surely generate a bite, stop the clutch function, and stop the outer ring 20 and the inner ring. 21 and the roller 22 can be prevented from returning to the first cam surface 21b again by the stepped surface 21d. Accordingly, even when an abnormality occurs, the function of transmitting the rotational force of the one-way clutch 13 is ensured, and the function of the device in which the one-way clutch 13 is incorporated can be more reliably maintained, and the reliability of the device can be improved. .

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

  The shape of the belt groove is not limited to the poly-V groove as in the present embodiment, and may be a tooth-shaped groove or a V-groove, and can be designed in an arbitrary shape. The one-way clutch built-in pulley device is not limited to a belt-driven one, and may be a coupling drive such as a rubber coupling.

  In the present embodiment, the outer ring 20 and the inner ring 21 of the one-way clutch 13 are provided separately from the pulley 12 and the sleeve 11, respectively, but may be formed integrally with the pulley 12 and the sleeve 11.

  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 formed integrally with the pulley or the sleeve, that is, constituted by the inner peripheral surface of the pulley or the outer peripheral surface of the sleeve.

  Furthermore, the cam surface of the present invention is not limited to the shape of the above embodiment, and the cam surface 21a ′ of the inner ring 21 is applied to the outer peripheral surface of a polygonal shape (for example, an octagon) as shown in FIG. May be.

  In addition, the one-way clutch of the present invention only needs to transmit a rotational force between the sleeve and the pulley, and the pulley tends to rotate relative to the sleeve in a predetermined direction as in the present embodiment. In this case, the clutch may be a one-way clutch that transmits a rotational force, or the outer peripheral surface of the clutch inner ring may be a cylindrical surface and the inner peripheral surface of the clutch outer ring may be a plurality of cam surfaces, and the sleeve may be in a predetermined direction relative to the pulley. A one-way clutch that transmits rotational force may be used only when it tends to rotate. In this case, as shown in FIG. 4, the outer ring 20 ′ may have a polygonal cam surface 20e having a first cam surface 20b, a second cam surface 20c, and a step surface 20d.

  Also, when the pulley device with a built-in clutch is used for driving an auxiliary machine of an engine idle stop mechanism, the auxiliary machine such as a compressor is driven by a dedicated motor when the engine is stopped, so that the engine rotation fluctuation is not affected. However, it becomes a structure which receives the rotation fluctuation which generate | occur | produces from the motor for an auxiliary machine drive.

It is a longitudinal cross-sectional view of the one-way clutch built-in pulley apparatus which concerns on one Embodiment of this invention. (A) is a schematic sectional drawing of the one-way clutch of FIG. 1, (b) is the II section enlarged view of (a). It is sectional drawing which shows the inner ring | wheel which concerns on the modification of a one way clutch. It is sectional drawing which shows the outer ring | wheel which concerns on the other modification of a one way clutch.

Explanation of symbols

10 Pulley device with built-in one-way clutch 11 Sleeve 12 Pulley 13 One-way clutch 14 Support bearing 20 Outer ring 21 Inner ring 21a Cam surface 21b First cam surface 21c Second cam surface 21d Step surface

Claims (1)

An inner ring, an outer ring, a cam surface formed on an outer peripheral surface of the inner ring or an inner peripheral surface of the outer ring, a cam surface of the inner ring and an inner peripheral surface of the outer ring, or an outer ring cam surface and an outer periphery of the inner ring A roller disposed in a wedge space formed between the surface and
When one of the outer ring and the inner ring rotates relative to the other in a predetermined direction, the roller is engaged in the wedge space, and the outer ring and the inner ring are substantially coupled to each other, and the other driving force Is a one-way clutch that releases the biting in a state where the one driving force is greater than the one driving force,
The cam surface is formed continuously from a first cam surface in which the rollers are normally engaged and released from the engagement, and from the first cam surface in the engagement direction, and a wedge angle of the first cam surface A radial space of the wedge space is formed between the second cam surface having a smaller wedge angle and the first cam surface and the second cam surface from the first cam surface toward the second cam surface. A stepped surface formed to spread,
When the roller is caught on the second cam surface beyond the stepped surface, the one-way clutch is always in a coupled state, and the one-way clutch cannot be released. And one-way clutch.

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