JP2007177935A - One-way roller clutch and pulley with built-in clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way roller clutch having high accuracy and low cost. <P>SOLUTION: An cylindrical face 16 is formed on the inner periphery of an outer ring 11, a plurality of flat cam faces 17 forming a wedge shaped space between the cylindrical face 16 and each of them are provided at peripherally equal intervals on the outer periphery of a pulley hub 12 incorporated inside the outer ring 11, and pockets 20 are formed in a cage 13 incorporated between the outer ring 11 and the pulley hub 12 at positions opposite to the cam faces 17. A roller 14 and an elastic member 15 for thrusting the roller 14 toward a narrow portion of the wedge shaped space is incorporated in each pocket 20. In a cutting method for rotating a tool holder 40 mounted with a plurality of cutters 41 and a pulley hub 12 arranged parallel thereto at a predetermined rotation ratio in the same direction, the cam faces 17 on the outer periphery of the pulley hub 12 are cut and then induction-hardened, resulting in reduced cost. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a one-way roller clutch that transmits one-way rotation of a driving member to a driven member, and a clutch built-in pulley in which the one-way roller clutch is incorporated.

  Generally, in an internal combustion engine of an automobile, rotation of an engine crankshaft is transmitted to a rotation shaft of an engine auxiliary machine such as an alternator via a belt transmission.

  In the engine accessory drive apparatus as described above, when the engine is suddenly decelerated, the pulley attached to the rotating shaft of the engine accessory also tries to decelerate rapidly. However, when the engine accessory is an alternator, the rotating shaft of the alternator has a large inertial force, so the pulley attached to the rotating shaft tries to keep rotating at a constant speed, and the pulley on the crankshaft and the rotating shaft of the alternator A large rotational speed difference is generated between the upper pulley and the belt tension increases, and the belt is easily damaged.

  Also, the crankshaft has an angular velocity that changes during one rotation, and due to the change in the angular velocity, slippage occurs between the pulley on the crankshaft and the belt, and the belt wears due to the slippage, resulting in durability. Will drop.

  In order to eliminate such inconvenience, Patent Document 1 proposes a pulley with a built-in clutch in which a one-way roller clutch is incorporated in a pulley provided on a rotating shaft of an engine accessory.

  When the pulley with a built-in clutch as described above is mounted on the rotating shaft of the engine accessory, the one-way roller clutch is disengaged and the pulley rotates freely when the rotating speed of the pulley is lower than the rotating speed of the rotating shaft of the engine accessory. Therefore, an increase in belt tension can be prevented, slippage between the pulley and the belt can be prevented, and a decrease in durability of the belt can be suppressed.

  Here, in the one-way roller clutch incorporated in the pulley with built-in clutch, the inner circumference of the pulley is a cylindrical surface, and a wedge-shaped space is formed between the outer circumference of the pulley hub incorporated in the pulley and the cylindrical surface. In the cage that is provided between the pulley and the pulley hub and is prevented from rotating around the pulley hub, a pocket is formed at a position facing each cam surface. A roller and an elastic member that presses the roller toward the narrow portion of the wedge-shaped space are incorporated.

In the one-way roller clutch as described above, since a relatively high meshing accuracy is required, usually carburizing and quenching is performed after forging a pulley hub having a flat cam surface on the outer periphery using carburized steel. I have to. Moreover, since the accuracy of a cam surface is bad if it has been hardened, the cam surface is ground after carburizing and quenching.
JP 2002-206571 A

  By the way, as described above, the pulley hub in the one-way roller clutch is subjected to carburizing and quenching after forging, and the cam surface is formed by grinding. There is a problem that the processing cost is high.

  An object of the present invention is to provide a one-way roller clutch and a pulley with a built-in clutch that are highly accurate and inexpensive.

  In order to solve the above problems, in the one-way roller clutch according to the present invention, a cylindrical surface is formed on the inner periphery of the outer ring, and the outer surface of the inner ring incorporated inside the outer ring is between the cylindrical surface. A plurality of flat cam surfaces forming a wedge-shaped space are provided at equal intervals in the circumferential direction, and a cage is formed between the outer ring and the inner ring, and a pocket is formed at a position facing the cam surface. In a one-way roller clutch incorporating a roller and an elastic member that presses the roller toward a narrow portion of the wedge-shaped space, the flat cam surface is formed by cutting, and the cam surface is subjected to heat treatment. Adopted.

  Here, when cutting the cam surface, the tool holder and the inner ring arranged in parallel are rotated in the same direction at a predetermined rotation ratio, and the outer periphery of the inner ring is cut into a polygon by a plurality of blades attached to the tool holder. By adopting the cutting method, the plurality of cam surfaces can be efficiently formed in a short time, and the processing cost can be further reduced.

  Also, by forming the inner ring with high carbon steel and adopting induction hardening as heat treatment of the cam surface, it is possible to obtain a cam surface with high surface accuracy, high meshing accuracy, and low cost one-way roller clutch. Can get.

  In the pulley with a built-in clutch according to the present invention, in the pulley with a built-in clutch in which the one-way roller clutch is incorporated inside the pulley, the one-way roller clutch having the above-mentioned configuration is adopted as the one-way roller clutch.

  By forming a plurality of flat cam surfaces provided on the outer periphery of the inner ring by cutting and heat-treating the cam surfaces, the cam surfaces can be formed at low cost and with high accuracy, with high meshing accuracy and low cost. A directional roller clutch and a pulley with a built-in clutch can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 3, the pulley with a built-in clutch includes a pulley 1, a one-way roller clutch 10 incorporated inside the pulley 1, and a pair of bearings 30 incorporated on both sides of the one-way roller clutch 10. A double-row V-groove 2 is provided on the outer periphery of the pulley 1 so as to span a V-ribbed belt.

  The one-way roller clutch 10 includes an outer ring 11 that is press-fitted into the inner diameter surface of the pulley 1, a pulley hub 12 as an inner ring that is attached to the rotating shaft of the auxiliary machine, and a cage 13 that is incorporated between the outer ring 11 and the pulley hub 12. The roller 14 is held by the retainer 13 and the elastic member 15 presses the roller 14 in the circumferential direction. A cylindrical surface 16 is formed on the inner periphery of the outer ring 11.

  The pulley hub 12 has a cam ring 12a at the center in the axial direction, a pair of small-diameter cylindrical portions 12b are formed at both ends of the cam ring 12a, and the bearing incorporated between each small-diameter cylindrical portion 12b and the pulley 1. 30, the pulley 1 and the pulley hub 12 are relatively rotatable.

  On the outer periphery of the cam ring 12a, a plurality of flat cam surfaces 17 forming a wedge-shaped space with the cylindrical surface 16 of the outer ring 11 are provided at equal intervals in the circumferential direction.

  The cam surface 17 is formed by cutting. Each cam surface 17 is increased in hardness by heat treatment after cutting. Here, the cam surface 17 is cut by a cutting device called a polygon machine.

  FIG. 4 shows a schematic diagram of the cutting apparatus. This schematic diagram shows a case where the outer periphery of a cylindrical workpiece W is cut into a hexagon. That is, three cutting tools 41 are attached to the cutting tool holder 40 at an interval of 120 °, and the cutting tool 41 and the workpiece W are rotated in the same direction with a rotation ratio of 2 to 1, and each cutting tool 41 is rotated. Thus, the outer periphery of the workpiece W is cut. F indicates a cutting surface.

  Here, as shown in FIGS. 2 and 3, when cutting the outer periphery of the cam ring 12a into a dodecagon, six cutting tools 41 are attached to the cutting tool holder 40 at intervals of 60 °. The pulley hub 12 is rotated in the same direction with a rotation ratio of 2: 1.

  Here, in the heat treatment of the cam surface 17, only the cam surface 17 is quenched by induction hardening. The pulley hub 12 is made of high carbon steel for induction hardening. As described above, the high-carbon steel is adopted as the material of the pulley hub 12 and induction hardening is performed after the cam surface 17 is cut, so that the heat treatment deformation is less than that in the case where the carburized steel is carburized and quenched. A highly accurate cam surface 17 can be obtained.

  As shown in FIG. 2, the retainer 13 is fitted to the outside of the cam ring 12 a, and is prevented from rotating on the pulley hub 12 by the engagement of the flat engagement surface 18 formed on the inner periphery of the cage 13 and the cam surface 17. .

  Further, as shown in FIG. 1, the retainer 13 is formed with an inward flange 19 at one end, and the retainer 13 is not movable in the axial direction by engagement of the flange 19 and one end surface in the axial direction of the cam ring 12a. It is said that.

  A pocket 20 is formed in the retainer 13 at a position facing the cam surface 17 of the cam ring 12a. The roller 14 and the elastic member 15 are incorporated in the pocket 20, and the roller 14 is wedge-shaped by the elastic member 15. It is pressing toward the narrow part of the space.

  In the pulley with built-in clutch configured as described above, when driving the alternator as an engine accessory, a pulley hub 12 is attached to the rotating shaft of the alternator, and a belt is passed between the pulley 1 and the pulley attached on the crankshaft. The rotation of the crankshaft is transmitted to the pulley 1.

  In the state of use as described above, when the pulley 1 is rotated in the direction indicated by the arrow in FIG. It is transmitted to the pulley hub 12.

  When the rotational speed of the pulley hub 12 exceeds the rotational speed of the pulley 1 during transmission of rotational torque from the pulley 1 to the pulley hub 12, the engagement of the roller 14 with the cylindrical surface 16 and the cam surface 17 is released, and the pulley 1 is pulled from the pulley hub. The rotation transmission to 12 is cut off, and the pulley 1 rotates freely.

  As shown in the embodiment, by forming the flat cam surface 17 on the outer periphery of the pulley hub 12 by cutting and heat-treating the cam surface 17, the cam surface 17 can be formed at low cost and with high accuracy. A highly accurate and inexpensive one-way roller clutch and a pulley with a built-in clutch can be obtained.

  Further, when the cam surface 17 is cut, a cutting method is employed in which the cutting tool 41 to which the cutting tool 41 is attached and the pulley hub 12 made of high carbon steel are rotated in the same direction at a predetermined rotation ratio and cut. Thereafter, by induction hardening only the cam surface 17, a plurality of cam surfaces 17 with high surface accuracy can be efficiently formed in a short time, and the processing cost can be further reduced.

  In the embodiment, the cylindrical surface 16 is formed on the inner periphery of the outer ring 11 fitted to the inner diameter surface of the pulley 1, but the outer ring 1 is omitted, and the pulley 1 is used as the outer ring to form a cylindrical surface on the inner periphery. May be.

A longitudinal front view showing an embodiment of a one-way roller clutch according to the present invention Sectional view along the line II-II in FIG. Perspective view showing pulley hub Schematic diagram showing cam surface cutting method

Explanation of symbols

1 Pulley 10 One-way roller clutch 11 Outer ring 12 Pulley hub (inner ring)
13 Cage 14 Roller 15 Elastic member 16 Cylindrical surface 17 Cam surface 20 Pocket 40 Tool holder 41 Blade

Claims (4)

A cylindrical surface is formed on the inner periphery of the outer ring, and a plurality of flat cam surfaces forming a wedge-shaped space between the cylindrical surface and the outer periphery of the inner ring incorporated inside the outer ring are provided at equal intervals in the circumferential direction. The cage assembled between the outer ring and the inner ring is formed with a pocket at a position facing the cam surface, and a roller and an elastic member that presses the roller toward the narrow part of the wedge-shaped space are assembled in each pocket. 1-way roller clutch
A one-way roller clutch, wherein the flat cam surface is formed by cutting and heat treatment is applied to the cam surface.   The cam surface is formed by a cutting method in which a tool holder and an inner ring arranged in parallel are rotated in the same direction at a predetermined rotation ratio, and the outer periphery of the inner ring is cut into a polygon by a cutter attached to the tool holder. The one-way roller clutch according to claim 1.   The one-way roller clutch according to claim 1 or 2, wherein the heat treatment is induction hardening.   4. A clutch built-in pulley in which a one-way roller clutch is incorporated inside a pulley, wherein the one-way roller clutch comprises the one-way roller clutch according to claim 1.

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