JP2005233324A - Pulley unit with one-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulley unit with a one-way clutch, sealing the one-way clutch and a rolling bearing without any increase in width of the bearing. <P>SOLUTION: Rolling bearings 6, 7 are provided on both sides in the axial direction of the one-way clutch 5, and an outer ring of the one-way clutch 5 is held between the outer rings 6a, 7a of both rolling bearings 6, 7. The rolling bearings 6, 7 are one side sealing bearings having sealing seals 8, 9 at the outer end parts, and the end part of a retainer 15 of the one-way clutch 5 is provided with radial inward projecting parts 15a, 15b formed to form a labyrinth seal in a space up to the inner end parts of the inner rings 6b, 7b of the rolling bearings 6, 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pulley unit with a one-way clutch suitable for use in a belt drive starter, for example, in a belt transmission system that transmits a rotational force when starting an internal combustion engine and driving an auxiliary machine by an internal combustion engine using a belt. .

  A pulley unit with a one-way clutch in which a one-way clutch is provided between a shaft and a pulley arranged concentrically around the shaft, and rolling bearings are provided on both axial sides of the one-way clutch is, for example, a patent As described in Document 1, it is conventionally known.

In Patent Document 1, the outer rings and the inner rings of the one-way clutch and the rolling bearing are integrated, and grease common to the one-way clutch and the rolling bearing is sealed between the outer ring and the inner ring. Is being reduced.
JP2003-156075A

  According to the pulley unit with a one-way clutch described in Patent Document 1, since the one-way clutch and the rolling bearing are not sealed, there is a problem that wear powder moves from the bearing side to the one-way clutch side. As a countermeasure, double-seal bearings can be used. In this case, the bearing width is increased by the width of the seal groove, making it difficult to secure the width dimension of the one-way clutch, and a compact pulley unit can be used. There is a problem that it is difficult to obtain.

  An object of the present invention is to provide a pulley unit with a one-way clutch capable of sealing a one-way clutch and a rolling bearing without increasing the bearing width dimension.

  The pulley unit with a one-way clutch according to the present invention biases the rollers and rollers disposed between the inner ring, the outer ring, and both the wheels between the shaft and a pulley disposed concentrically around the shaft. In the pulley unit with a one-way clutch provided with a one-way clutch provided with a biasing member and a cage for holding the roller, and provided with a rolling bearing on at least one side in the axial direction of the one-way clutch. A one-side sealed bearing having a hermetic seal at the end, and a radially inward projecting portion that forms a labyrinth seal with the inner end of the inner ring of the rolling bearing at the end of the cage of the one-way clutch. It is characterized by being formed.

  The one-way clutch may have an outer ring that is a member different from the pulley and an inner ring that is a member different from the hollow shaft, and an intermediate portion of the pulley is an outer ring of the one-way clutch. The intermediate part of the one-way clutch may be the inner ring of the one-way clutch. In the case of the former (the outer ring and inner ring of the one-way clutch are separate members from the pulley or hollow shaft), for example, the inner diameter of the pulley is the same except for the annular groove portion for hermetic seal, and the outer ring of the bearing is Axial positioning is performed by contacting the outer ring of the one-way clutch. The outer diameter of the hollow shaft is the same except for the annular groove portion for hermetic sealing, and the inner ring of the bearing is positioned in the axial direction by contacting the inner ring of the one-way clutch during press-fitting. In the latter case (the pulley also serves as the outer ring of the one-way clutch and the hollow shaft also serves as the inner ring), for example, the inner diameter of the pulley is formed in a stepped shape in which both ends are larger in diameter than the intermediate part. The outer ring is positioned by the step portion of the pulley, and the inner ring of the bearing is positioned by positioning the outer ring.

  The inner peripheral edge of the radially inward projecting portion of the cage faces the inner end surface of the inner ring through a required gap. It is preferable that either one of the radially inward projecting portion of the cage and the inner end portion of the inner ring is provided with an annular notch that prevents both from coming into direct contact. Since centrifugal force acts on the grease when the pulley rotates, the seal between the radially inward protruding part of the cage and the inner end of the inner ring is not a hermetic seal but a labyrinth seal. Can be obtained.

  The hermetic seal of the one-side seal bearing is composed of a cored bar and an elastic seal held by the cored bar. The outer peripheral edge of the cored bar is press-fitted into the outer ring, and the inner peripheral edge of the elastic seal is brought into sliding contact with the inner ring.

By forming a labyrinth seal between the radially inward protruding part of the cage and the inner end of the inner ring, grease of different specifications (for example, different kinematic viscosities) is enclosed in the one-way clutch and the rolling bearing. can do. In this case, it is preferable to use a high-speed and high-speed grease as a rolling bearing grease, and it is preferable to use a low-speed startability as a one-way clutch grease. For example, grease having a kinematic viscosity at 40 ° C. of 90 mm ² / s or higher (more preferably, 98 mm ² / s or higher and 110 mm ² / s or lower) is enclosed in the rolling bearing, and 40 ° C. in the one-way clutch. Grease having a kinematic viscosity at 35 mm ² / s or less (more preferably 14 mm ² / s or more and 30 mm ² / s or less) is enclosed.

  According to the pulley unit with a one-way clutch of the present invention, the rolling bearing is a one-side sealed bearing having a hermetic seal at the outer end, and the inner end of the inner ring of the rolling bearing is disposed at the end of the cage of the one-way clutch. A radial inward projecting portion that forms a labyrinth seal is formed between the bearing and the bearing, so that the bearing need not be a double-seal bearing with a large width dimension, and without increasing the bearing width dimension, The rolling bearing can be sealed. In addition, since the centrifugal force acts on the grease as the pulley rotates, the labyrinth seal between the radially inward protruding portion of the cage and the inner end of the inner ring effectively contains wear powder and the like. This prevents the grease from moving in the axial direction and ensures the necessary sealing performance.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the left and right refer to the left and right in FIG.

  1 and 2 show an embodiment of a pulley unit with a one-way clutch according to the present invention.

  A pulley unit (1) with a one-way clutch is arranged at a portion connecting an engine drive unit and a rotation shaft of a starter motor, and is a hollow shaft (3) fitted to the rotation shaft (2) of the starter motor. And a pulley (4) arranged concentrically therewith, a one-way clutch (5) is provided. On the outer periphery of the pulley (4), there is provided a belt spanning part on which a V-ribbed belt is spanned. The one-way clutch (5) is provided between the axial intermediate portion of the hollow shaft (3) and the axial intermediate portion of the pulley (4), and the left end portion of the hollow shaft (3) and the pulley (4 ) And the left end portion of the hollow shaft (3), and between the right end portion of the hollow shaft (3) and the right end portion of the pulley (4), rolling bearings (6) and (7) are respectively provided. The inner diameter part of the middle part of the pulley (4) also serves as the outer ring of the one-way clutch (5), and the outer diameter part of the middle part of the hollow shaft (3) also serves as the inner ring of the one-way clutch (5). Yes.

  The inner diameter of the pulley (4) is formed in a stepped shape in which the left and right end parts (large diameter part) (4a) (4b) are larger in diameter than the intermediate part (small diameter part) (4c). The outer diameter of 3) is the same except for the annular groove portion for the hermetic seal (10).

  As shown in FIG. 2, the one-way clutch (5) includes a cam surface (11) provided on the inner peripheral surface of the intermediate portion of the pulley (4), and an intermediate between the cam surface (11) and the hollow shaft (3). The hollow shaft (3) is arranged in a wedge-shaped space (12) formed by the outer peripheral surface of the section, and the hollow shaft (3) and the pulley (4) are rotated relative to each other in one direction (locking direction). Roller (13) as a plurality of biting members that release between the pulley (4) and release the bite when rotated relative to the other direction (free direction) and the roller (13) in the biting direction ( A coil spring (14) as a biasing member that biases the wedge-shaped space (12) on the narrow side) and a cage (15) that positions the rollers (13) in the wedge-shaped space (12) are provided.

  The left and right rolling bearings (6) and (7) are ball bearings comprising outer rings (6a) and (7a), inner rings (6b) and (7b), balls (6c) and (7c), and cages (6d) and (7d), respectively. It is said that.

  The outer rings (6a) and (7a) of the left and right rolling bearings (6) and (7) have the outer diameters equal to the inner diameters of the left and right ends (4a) and (4b) of the pulley (4). The inner rings (6b) and (7b) are press-fitted into the left and right ends of the hollow shaft (3) with the inner diameter being equal to the outer diameter of the hollow shaft (3).

  Each of the rolling bearings (6) and (7) is a single-side sealed bearing, and the left end of the left rolling bearing (6) and the right end of the right rolling bearing (7) have a core metal (8a) (9a ) And the hermetic seals (8) and (9) composed of the elastic seals (8b) and (9b) held by them. The hermetic seals (8) and (9) have the outer peripheral edge of the metal core (8a) and (9a) press-fitted into an annular groove provided on the inner diameter of the outer end of the outer ring (6a) and (7a) in the axial direction. The inner peripheral edges of the elastic seals (8b) (9b) are in sliding contact with the inner rings (6b) (7b). On the free end side of the pulley unit (the left end side in the figure), another sealing seal (10) is installed between the left end of the hollow shaft (3) and the pulley (4) to prevent muddy water from entering the pulley unit. ) Between the left end and

  As shown in FIG. 2, the cam surface (11) of the one-way clutch is provided with a plurality of sets (four sets in this embodiment) of the cam surfaces (11a) facing each other across the shaft center in the circumferential direction. It is configured. Each surface (11a) is not perpendicular to the normal passing through the center and axis of the roller (13), but has an acute angle slightly smaller than the right angle.

  At the end of each side (11a) of the cam on the wide side of the wedge-shaped space (12), there is provided a holding concave surface portion (16) for stopping the roller (13) receiving a centrifugal force with a circular cross section. ing.

  The coil spring (14) has an elliptical shape having a central axis in a cross section and having the major axis direction aligned with the axial direction of the one-way clutch (5). The length of the short diameter, that is, the radial dimension of the portion in contact with the roller of the spring is made smaller than the diameter of the roller (13).

  The cage (15) is made of synthetic resin and has an outer peripheral shape substantially along the cam surface (11) and an inner peripheral shape along the outer peripheral surface of the hollow shaft (3), and within the cam surface (11). It is press-fitted. A slight gap is provided between the inner diameter of the cage (15) and the outer diameter of the hollow shaft (3) to prevent the cage (15) and the hollow shaft (3) from contacting each other. Yes. The cage (15) is provided with a spring receiving recess (17) for positioning the coil spring (14). The spring receiving recess (17) is filled with grease suitable for a one-way clutch.

  The spring receiving recess (17) is connected to the roller holding concave portion (16) of the cam surface (11) and the spring positioning surface (18) provided on the inner periphery of the pulley (4) to The central axis direction is kept constant. The central axis of the coil spring (14) is such that when the centrifugal force acts on the coil spring (14), the coil spring (14) is deformed in a direction that reduces the biasing force against the roller (13). It is inclined with respect to the tangential direction. As with the cam surface (11), the spring positioning surface (18) of the pulley (4) is provided with a plurality of sets of two surfaces formed opposite to each other across the axis of the one-way clutch (5) in the circumferential direction. Is made up of.

  The spring receiving recess (17) includes a spring end positioning surface (17a) that prevents the coil spring (14) from moving in the spring axis direction, and the coil spring (14) moves inwardly perpendicular to the spring axis. And a spring positioning surface (18) of the pulley (4) that prevents the coil spring (14) from moving perpendicularly to the spring axis. It is a spring outer positioning surface for blocking. By these spring positioning surfaces (17a), (17b) and (18), the central axis of the coil spring (14) is kept perpendicular to the central axis of the roller (13).

  A roller holding inclined surface (17c) is provided continuously to the spring inner positioning surface (17b) of the spring receiving recess (17). The other end of the inclined surface (17c) has a slight gap with respect to the outer peripheral surface of the hollow shaft (3). Roller moved in the biting release direction by the roller holding concave surface portion (16) which is the roller holding surface of the pulley (4) and the roller holding inclined surface (17c) which is the roller holding surface of the cage (15) ( 13) A roller holding portion having a substantially C-shaped cross section for receiving and holding is formed.

  The roller (13) indicated by a two-dot chain line in FIG. 2 shows a state when the centrifugal force is not working, and when the hollow shaft (3) is rotated counterclockwise in this state, (13) is caught between the hollow shaft (3) and the pulley (4), and the hollow shaft (3) and the pulley (4) rotate together. When the pulley (4) rotates at a high speed and the rotation of the hollow shaft (3) is stopped, the direction of centrifugal force (13) acting on the roller (13) comes into contact with each surface (11a) of the cam. The roller (13) is subjected to a force in the direction along each surface (11a) of the cam due to a deviation from the normal direction at the point where the roller (13) is positioned. Move to the wider side.

  In this state, the concave surface portion (16) which is the roller holding surface of the pulley (4) is a concave surface having an arc-shaped cross section having substantially the same radius as the radius of the outer peripheral surface of the roller (13). As shown by a solid line in FIG. 2, the outer peripheral portion thereof is just contained in the concave surface portion (16), and from the radially inner side, an inclined surface (which is a roller holding surface of the cage (15)) ( 17c) is applied so that the roller (13) does not tilt and a clearance is secured between the hollow shaft (3) and the outer periphery (13), and the hollow shaft (3) is not in contact with (13). A state is achieved.

  As shown in FIG. 2, the cage (15) is formed symmetrically, and its outer diameter is press-fitted into the pulley intermediate portion (4c), thereby preventing movement in the radial direction. The left end face of the outer ring (6a) of the left ball bearing (6) faces the right end face of the outer ring (6a) with substantially no gap, and the right end face of the outer ring (7) of the right ball bearing (7) By facing the left end face of 7a) with substantially no gap, movement in the axial direction is prevented. The axial length of the cage (15) is the same as the axial length of the pulley intermediate portion (4c).

  The pillars located at the left and right ends of the cage (15) are radially inwardly projecting so as not to contact the inner end surfaces of the inner rings (6b) and (7b) of the left and right rolling bearings (6) and (7). 15a) and 15b are provided, and the radially inward protruding portions (15a) and (15b) form a labyrinth seal between the inner ends of the inner rings (6b) and (7b). The radially inward protrusions (15a) and (15b) are positioned such that the axially outer surface is located more inward than the outer surface of the column body, and the labyrinth seal protrudes radially inwardly. The parts (15a) and (15b) are obtained by facing the inner end faces of the inner rings (6b) and (7b).

  When the pulley unit with a one-way clutch is used in a belt drive starter, the grease is required to have excellent meshing properties, wear resistance, and thermal stability. Engagement and wear resistance against meshing are characteristics required for one-way clutches in general, but thermal stability and wear resistance against slipping are characteristics that are required when idling is frequently used. The durability of the pulley unit with a one-way clutch is ensured by having both wearability and thermal stability. In addition, the one-way clutch of the belt drive starter is required to start the engine at a low temperature with respect to the enclosed grease in consideration of the use of an automobile in a cold region in winter.

Accordingly, grease having a kinematic viscosity at 40 ° C. of 35 mm ² / s or less is used as the grease enclosed in the one-way clutch. Specifically, in this grease, the base oil is ester-based, and the grease thickener is urea-based. Examples of the ester base oil include polyol esters. Antioxidants, rust inhibitors, extreme pressure additives, solid lubricants and the like are appropriately added to the grease. Such ester base oils have excellent viscosity index, thermal stability, and load resistance, and when used as a belt drive starter for an automobile engine in which the idling state is performed for an extremely long time, in addition to low-temperature meshing properties. , Can exhibit excellent durability.

The rolling bearing is filled with grease having a kinematic viscosity at 40 ° C. of 90 mm ² / s or more in consideration of high temperature and high speed. Specifically, in this grease, the base oil is an ether type, and the thickener of the grease is a urea type. Examples of the ether base oil include alkyl diphenyl ether. Antioxidants, rust inhibitors, extreme pressure additives, solid lubricants and the like are appropriately added to the grease. Such an ether base oil has good thermal stability and, in combination with a urea-based thickener, has excellent wear resistance of grease. When used as an engine belt drive starter, it is possible to exhibit more excellent durability.

  When assembling the pulley unit (1), for example, the right rolling bearing (7), the one-way clutch (5), and the left rolling bearing (6) are press-fitted in this order, but the inner diameter of the pulley (4) is Because of the stepped shape, the outer ring (6a) (7a) of each rolling bearing (6) (7) is prevented from further movement by the stepped portions at both ends of the intermediate portion (4c) of the pulley (4). Thus, deformation of the cage (5) and interference between the cage (5) and the rolling bearings (6) (7) are prevented.

  This one-way clutch-equipped pulley unit operates as follows.

First, at the time of starting, the hollow shaft (3) integrated with the rotation shaft (2) of the starter motor is rotated counterclockwise. As a result, the hollow shaft (3) of the one-way clutch (5) rotates counterclockwise, and the roller (13) is engaged with the narrow side of the wedge-shaped space (12) of the one-way clutch (5), and the driving force Is transmitted, and the hollow shaft (3) and the pulley (4) of the one-way clutch (5) rotate together. The pulley (4) is connected to the crankshaft via a belt, and the engine is started by the rotation of the pulley (4). Engine startability becomes a problem in extremely cold regions in winter, but the engine startability at low temperatures is ensured by keeping the kinematic viscosity of the grease of the one-way clutch (5) small. When the engine starts, the starter stops and the pulley (4) continues to rotate counterclockwise. As a result, the roller (13) is released and the state where only the pulley (4) rotates continues. In particular, when the engine rotates at high speed, the roller (13) is positioned by the concave surface portion (16) having substantially the same curvature as the roller (13), and is not in contact with the hollow shaft (3). Thus, at the time of starting, the roller (engagement member) (13) and the coil spring (biasing member) (14) rotate integrally with the pulley (4), and then the pulley (4) is rotated at a predetermined rotational speed. If it becomes above, only the pulley (4) will rotate and the energy loss accompanying the rotation of the part which does not contribute to the drive of an engine can be suppressed. Once the engine is started, the idle time during which only the pulley (4) rotates lasts from several tens of minutes to several hours, and during this time, the outer rings (6a) (7a) of the rolling bearings (6) (7) are rotated at high speed . Further, when the engine is driven, the rolling bearings (6) and (7) are repeatedly subjected to vibration in a high temperature environment. Since the grease enclosed in the rolling bearings (6) and (7) has a kinematic viscosity of 90 mm ² / s or more, even when used as a belt drive starter of an automobile engine in which the idling state is performed for an extremely long time, The durability performance of the rolling bearings (6) and (7) is ensured.

  In the above embodiment, the outer ring of the one-way clutch (5) is integrated with the pulley (4), and the inner ring is integrated with the hollow shaft (3). May be a separate member from the pulley (4), and the inner ring may be a separate member from the hollow shaft (3). Further, although the coil spring (14) is shown as means for biasing the roller (13), a plate spring or the like can be used instead of the coil spring (14).

FIG. 1 is a longitudinal sectional view showing an embodiment of a pulley unit with a one-way clutch according to the present invention. FIG. 2 is a partially enlarged view of the same cross section.

Explanation of symbols

(1) Pulley unit with one-way clutch
(3) Hollow shaft
(4) Pulley
(5) One-way clutch
(6) (7) Rolling bearing
(6b) (7b) Inner ring
(15) Cage
(15a) (15b) Radial inward protrusion

Claims (2)

Between the shaft and a pulley arranged concentrically around the shaft, an inner ring, an outer ring, a roller arranged between the two wheels, a biasing member that biases the roller in the biting direction, and a cage that holds the roller In the pulley unit with a one-way clutch provided with a one-way clutch with a rolling bearing provided on at least one side in the axial direction of the one-way clutch,
Radial direction in which the rolling bearing is a one-side sealed bearing having a hermetic seal at the outer end, and a labyrinth seal is formed between the inner end of the inner ring of the rolling bearing at the end of the cage of the one-way clutch A pulley unit with a one-way clutch, wherein an inward protruding portion is formed.   The pulley unit with a one-way clutch according to claim 1, wherein the grease base oil of the one-way clutch and the grease base oil of the rolling bearing have different kinematic viscosities.

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