JP2003004121A - Pulley unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the dimension of a pulley unit in the axial direction shorter than a conventional one while securing the space for forming a peripheral groove to which a seal lip of an annular seal can abut with a sufficient interference. SOLUTION: The pulley unit comprises a pulley 1, a rotor shaft 2, a one-way clutch 3, a ball bearing 4, a roller bearing 5 and the annular seal 61. The roller bearing 5 has a holder 51 in which a projection is formed projecting inward in the radial direction on the one-way clutch 3 side. The annular seal 61 is fixed to the inner surface of the pulley 1, and has the seal lip 61a at the top. A stopper groove 2d to which the projection 52 is inserted and engaged and a seal groove 2f into which the seal lip 61a is inserted are formed on the outer peripheral surface of the rotor shaft 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulley unit having a one-way clutch. This pulley unit can be mounted on an auxiliary machine driven by a belt from a crankshaft of an engine of an automobile, for example. Examples of auxiliary equipment include compressors for automobile air conditioners, water pumps, alternators,
A cooling fan etc. are mentioned.

[0002]

2. Description of the Related Art Various accessories mounted on an automobile engine are driven by a crankshaft of the engine via a belt. Here, for example, in the case of an alternator among the auxiliary machines, if it is connected so as to rotate in synchronization with the crankshaft of the engine, the power generation capacity of the alternator decreases when the rotation speed of the crankshaft decreases. Therefore, the applicant of the present application incorporates the one-way clutch in the pulley portion of the alternator so that when the rotation speed of the crankshaft decreases, the rotation of the rotor of the alternator is continued by its inertial force to improve the power generation efficiency. I have already applied for some of the pulley units that can be enhanced.

FIG. 4 shows one of the unknown pulley units associated with the applicant's application. In FIG.
1 is a pulley, 2 is a rotor shaft, 3 is a one-way clutch, 4 is a ball bearing, 5 is a roller bearing, 61 and 62 are annular seals, and 7 is an annular shield plate.

In the figure, one side (right side) in the axial direction is the engine side, and the crankshaft is inserted into the inner circumference of the rotor shaft 2 from the right side.

This pulley unit switches the one-way clutch 3 between a locked state in which power is transmitted and a free state in which power transmission is interrupted in accordance with a rotation difference between the pulley 1 and the rotor shaft 2, and the pulley 1 and the rotor shaft 2 are rotated. It is designed to transmit and block power between the two.

Then, on the outer peripheral surface of the rotor shaft 2, a ring-shaped projection 5 provided on the inner peripheral surface of the cage 51 of the roller bearing 5.
2 is engaged, the retaining groove 2d for retaining the retainer 51 in the axial direction, and the seal lip 6 of the annular seal 61.
A seal groove 2f into which 1a is inserted is provided.

The ring-shaped projection 52 of the retainer 51 is
Since it is provided on the annular seal 61 side, the retaining groove 2d and the seal groove 2f are provided adjacent to each other in the axial direction of the rotor shaft 2.

[0008]

As described above, both grooves 2 are formed.
If d and 2f are adjacent to each other, it is necessary to provide them at a required axial distance in order to avoid a decrease in strength of the rotor shaft 2. In this case, the seal groove 2f side is required to be separated from the retaining groove 2d by a required distance. There is no choice but to form them in separate places.

On the other hand, since the seal lip 61a is of the radial interference type, the rotor shaft 2 needs a space for forming the corresponding seal groove 2f.

For this reason, in the conventional pulley unit, the dimension in the axial direction is lengthened to secure the installation space for the seal groove 2f, which increases the dimension in the axial direction.

Therefore, according to the present invention, in the pulley unit, the space for forming the seal groove with which the seal lip of the annular seal can abut with a sufficient tightening margin is secured, and the axial dimension of the pulley unit is larger than that of the conventional one. It is an issue to solve what can be shortened.

[0012]

According to the present invention, there is provided a pulley, a shaft body which is rotatable relative to the pulley and is concentrically arranged inside the pulley, and a ring between the pulley and the shaft body. A one-way clutch interposed in the space, and rolling bearings provided on both sides of the one-way clutch in the annular space,
A pulley unit including an annular seal for sealing an outer end surface side of a rolling bearing on a free end side, wherein the rolling bearing on the free end side is a retainer formed with a protrusion radially inward on the one-way clutch side. The annular seal is fixed to the inner peripheral surface of the pulley and has a seal lip at its tip, and the retaining groove and the seal lip into which the protrusion engages with the outer peripheral surface of the shaft body. It is characterized in that each of them has a seal groove formed therein.

In the above description, the shaft body includes the input shaft itself of the automobile accessory and a part of the input shaft. In short, the input shaft is, if it is a shaft body which is arranged concentrically with the pulley on the inner diameter side thereof and rotates relative to the pulley, a hollow structure, a partially hollow structure, a solid structure, a double shaft structure, etc. Including all.

According to the present invention, since the retaining groove and the seal groove are formed separately from each other on the outer peripheral surface of the shaft body through the cage, the both grooves are formed adjacent to each other as in the conventional case. The strength does not decrease as compared with the case of Since the seal groove can be provided with a sufficient space with respect to the outer peripheral surface of the shaft body without increasing the axial dimension of the shaft body, the annular seal seals the seal lip with a sufficient tightening margin. It will come into contact with the groove.

Therefore, in the present invention, in the pulley unit, the axial dimension of the pulley unit is made larger than that of the conventional one, while ensuring the space for forming the circumferential groove in which the seal lip of the annular seal can abut with a sufficient tightening margin. It can be shortened.

Further, the retainer is provided with a radially inward projection that engages with the retaining groove, and the retainer is axially retained by engaging the protrusion with the retaining groove. it can.

In the above case, preferably, the seal groove has a first inner wall surface having a shape along the radial direction and a second inner wall surface having a taper shape whose groove bottom becomes shallower toward the free end side. Then, the first inner wall surface is formed in a shape along the radial direction, and the second inner wall surface is formed in a tapered shape. With this configuration, the seal lip comes into axial contact with the first inner wall surface of the seal groove, so that the contact state between the seal lip and the first inner wall surface is unlikely to change when a rotational centrifugal force is applied, and the annular shape When installing the seal on the shaft,
Even if the seal lip of the annular seal is tilted during the assembling process, it can be easily restored to the correct posture with respect to the seal groove, so that the desired sealing performance can be secured for a long time, which is preferable.

[0018]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described based on the embodiments shown in the drawings.

1 to 3 relate to an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a pulley unit, FIG. 2 is a sectional view taken along line (2)-(2) of FIG. FIG. 3 is an enlarged view of a main part of FIG.

The pulley unit A in the illustrated example includes a pulley 1, a rotor shaft 2, a one-way clutch 3, a ball bearing 4, a roller bearing 5,
It has annular seals 61 and 62 and an annular shield plate 7.

In this pulley unit A, in order to reduce the number of parts and the manufacturing cost, the inner and outer rings of the one-way clutch 3 and the inner and outer rings of the ball bearing 4 and the roller bearing 5 are omitted, and the pulleys of these inner rings are pulleys. Rotor shaft of unit A
2 is also used, and the outer ring is also used as pulley 1.

The pulley 1 is rotatably driven, for example, by a crankshaft of an automobile engine via a V-ribbed belt B, and has a wavy groove around which the V-ribbed belt B is wound.

A raceway groove in which a ball 41 of a ball bearing 4 made of a deep groove ball bearing is inserted is formed in a region on the inner peripheral surface of the pulley 1 on the axially fixed side.

The rotor shaft 2 is inserted as a hollow shaft into the pulley 1 and is fixed to an input shaft (for example, an alternator rotor) of an accessory of an automobile engine (not shown).

On the outer peripheral surface of the rotor shaft 2, flat cam surfaces 31 of the one-way clutch 3 are formed at several circumferential positions in the axially intermediate region 2a, and ball bearings 4 are formed in the axially opposite regions 2b and 2c. The inner ring raceway of the roller bearing 5 is secured.

The intermediate region 2a of the rotor shaft 2 is formed in an octagonal shape, and both side regions 2b, 2c are formed in a circular shape.

In the rotor shaft 2, the outer diameter dimension of the region 2b which becomes the inner ring raceway of the ball bearing 4 is set to be larger than the outer diameter dimension of the region 2c which becomes the inner ring raceway of the roller bearing 5.
This is so that the one-way clutch 3, the ball bearing 4, and the roller bearing 5 can be easily assembled between the pulley 1 and the rotor shaft 2 in order from the fixed side in the axial direction. In a region 2b of the rotor shaft 2, a raceway groove in which a ball 41 of a ball bearing 4 composed of a deep groove ball bearing is inserted is formed.

The one-way clutch 3 is interposed in the axial center of the opposing annular space S between the pulley 1 and the rotor shaft 2,
The inner ring raceway is formed by the outer peripheral surface of the rotor shaft 2, and the outer ring raceway is formed by the inner peripheral surface of the pulley 1.

The one-way clutch 3 includes an annular cage 32 made of synthetic resin, a plurality of rollers 33 as rolling elements, and an elliptical coil spring 34 as an elastic member.

In this case, the retainer 32 of the one-way clutch 3
Is disposed in the opposed annular space S between the pulley 1 and the rotor shaft 2 and is externally mounted in a state of being positioned in the circumferential direction and the axial direction. On the outer peripheral surface of the rotor shaft 2, there are several cam surfaces 31 in the circumferential direction. A pocket 35 penetrating inward and outward in the radial direction is provided in a region corresponding to. An axial column portion 36 exists between the respective circumferential directions of the pockets 35.

The roller 33 of the one-way clutch 3 is the cage 3
Each of the two pockets 35 is housed with its circumferential rolling range restricted.

The coil spring 34 of the one-way clutch 3 is attached to the projection 37 projecting from the inner wall surface of each column portion 36 of the retainer 32, and the roller 33 is fixed to the cam surface 31 and the inner peripheral surface of the pulley 1. Narrow side of the wedge-shaped space formed by and (lock side)
It pushes to.

The inner peripheral surface of the retainer 32 of the one-way clutch 3 is formed into a shape that fits and fits the octagonal outer peripheral surface of the axially intermediate region 2a of the rotor shaft 2, so that the retainer 32 is rotated. The shaft 2 is prevented from rotating in the circumferential direction.

The retainer 32 of the one-way clutch 3 is
The movement toward the ball bearing 4 side is blocked by the tapered step portion 2e that connects the cam surface 31 of the intermediate region 2a of the rotor shaft 2 to the large diameter region 2b, and is axially positioned with respect to the rotor shaft 2. The cage 51 of the roller bearing 5 blocks the movement toward the roller bearing 5.

The ball bearing 4 and the bearing 5 are provided as rolling bearings, one on each axial side of the one-way clutch 3 in the opposed annular space S between the pulley 1 and the rotor shaft 2.

The ball bearing 4 has its inner ring raceway formed on the outer circumferential surface in the axial direction one region 2b of the rotor shaft 2 and its outer ring raceway formed on the inner circumferential surface of the pulley 1, and has a plurality of balls 41 as rolling elements. And a general deep groove type ball bearing consisting of a crown-shaped cage 42 for holding it.

In the roller bearing 5, the inner ring raceway is the rotor shaft 2
The outer ring raceway is formed on the outer peripheral surface in the other axial direction region 2c of the inner peripheral surface of the pulley 1, and is a cage and roller composed of a plurality of rollers 53 as rolling elements and a retainer 51 holding the rollers. ing.

In the annular space S, annular seals 61 and 62 are mounted on the axially outer end sides of the ball bearing 4 and the roller bearing 5. Each of the annular seals 61, 62 has one end of an elastic body attached to the outer periphery of the annular core fixed to the inner peripheral surface of the pulley 1, and the other end on the outer peripheral surface of the rotor shaft 2 as seal lips 61a, 62a. It is in the form of abutting contact.

In operation of the pulley unit A, the one-way clutch 3 is in a locked state or a free state in accordance with the rotational speed difference between the pulley 1 and the rotor shaft 2, and power is transmitted from the pulley 1 to the rotor shaft 2. Transmission or cut off power transmission. When the one-way clutch 3 is in the free state, the rotor shaft 2 continues to rotate due to its own rotational inertia.

With the above-described structure, in the present embodiment, the ring-shaped projection 52 is provided radially inward on the one-way clutch 3 side of the retainer 51 provided on the roller bearing 5 on the free end side, and the outer periphery of the rotor shaft 2 is provided. A retaining groove 2d that engages the ring-shaped protrusion 52 and prevents the retainer 51 from coming off is formed on the surface. Further, on the outer peripheral surface of the rotor shaft 2, there is formed a seal groove 2f into which the main seal lip 61a provided in the annular seal 61 for sealing the outer end surface side of the roller bearing 5 enters.

The annular seal 6 is fixed to the inner peripheral surface of the pulley 1 and has a seal lip 61a at its tip.

According to this embodiment, the retainer groove 2d and the seal groove 2f are provided on the outer peripheral surface of the rotor shaft 2 in the cage 5.
Since the grooves are formed apart from each other in the axial direction through the groove 1, the strength of the grooves 2d and 2f does not decrease as compared with the case where the grooves 2d and 2f are formed adjacently. Since the seal groove 2f can be provided with a sufficient space with respect to the outer peripheral surface of the rotor shaft 2 without increasing the axial dimension of the rotor shaft 2, the annular seal 61 has a sufficient main seal lip 61a. Seal groove 2 with tightening allowance
It comes to contact with f.

Therefore, in this embodiment, the axial dimension of the pulley unit A is set to that of the conventional one while ensuring the space for forming the seal groove 2f with which the main seal lip 61a of the annular seal 61 can abut with a sufficient tightening margin. It can be shortened more than.

The above-mentioned features will be described in more detail. In the annular seal 61, an elastic body 61d such as rubber is adhered to an annular core metal 61c.
The inner peripheral portion of d is provided with a main seal lip 61a extending radially toward the center and an auxiliary seal lip 61b extending obliquely inward from the root of the main seal lip 61a toward the inside of the roller bearing 5.

Further, the seal groove 2f has a first inner wall surface 2f1.
And a second inner wall surface 2f2. And the first inner wall surface 2
The f1 is formed in a shape along the radial direction, and the second inner wall surface 2f2 is formed in a tapered shape in which the groove bottom becomes shallower toward the free end side.

Main seal lip 61a of the annular seal 61
Is in axial contact with the first inner wall surface 2f1 of the seal groove 2f, and the auxiliary seal lip 61b is
It is opposed to the outer peripheral surface of the rotor shaft 2 via a minute gap without entering the seal groove 2f.

In such a case, since the main seal lip 61a comes into axial contact with the first inner wall surface 2f1 of the seal groove 2f, when the rotational centrifugal force acts, the main seal lip 61a and the first inner wall surface 2f1. The state of contact with is unlikely to change, so the desired sealing performance can be secured.

The present invention is not limited to the above-mentioned embodiment, and it goes without saying that various forms can be applied.

Further, the present invention is not limited to the pulley unit in which the inner and outer rings of the ball bearing 4 and the roller bearing 5 are integrally formed on the pulley 1 and the rotor shaft 2, and further, the rolling units provided on both sides of the one-way clutch 3 are provided. The bearing is not limited to the above embodiment, but can be applied to various types of pulley units.

[0050]

As described above, according to the present invention, the pulley, the shaft body which is rotatable relative to the pulley and concentrically arranged inside the pulley, and the pulley and the shaft body are provided. A pulley unit including a one-way clutch interposed in an annular space between the rolling bearings, rolling bearings provided on both sides of the one-way clutch in the annular space, and an annular seal for sealing the outer end surface side of the rolling bearing on the free end side. The rolling bearing on the free end side has a cage formed with a protrusion inward in the radial direction on the one-way clutch side, the annular seal is fixed to the inner peripheral surface of the pulley, and Since the tip has a seal lip, and a retaining groove into which the protrusion engages and a seal groove into which the seal lip enters are formed on the outer peripheral surface of the shaft body, respectively, the retaining groove and the seal groove retain the retaining groove. vessel Results that are formed away via, it is not like the strength is reduced as compared with the case where the both grooves as in the prior art have been formed adjacent. Since the seal groove can be provided with a sufficient space with respect to the outer peripheral surface of the shaft body without increasing the axial dimension of the shaft body, the annular seal seals the seal lip with a sufficient tightening margin. Since it can be brought into contact with the groove, the axial dimension of the pulley unit can be shortened compared to the conventional one while ensuring the space for forming the circumferential groove where the seal lip of the annular seal can contact with a sufficient tightening margin. Can be

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a pulley unit according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line (2)-(2) of FIG.

FIG. 3 is an enlarged view of a peripheral main part of the annular seal of FIG.

FIG. 4 is a vertical sectional view of a conventional pulley unit.

[Explanation of symbols]

A pulley unit B belt 1 pulley 2 Rotor shaft (shaft body) 2d retaining groove 2f seal groove 3 one-way clutch 4 ball bearings 5 Roller bearing (free end side rolling bearing) 51 protrusions 6 annular seal 61a seal lip

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16C 33/78 F16C 33/78 DF term (reference) 3J016 AA02 BB03 CA02 CA07 3J031 AC06 AC10 BA04 BA08 BA19 CA03 CA10 3J101 AA13 AA24 AA32 AA42 AA52 AA62 AA72 AA77 AA83 BA22 BA53 BA54 BA55 BA56 BA73 BA77 EA01 EA49 FA13 FA15 FA53 GA01 GA21 GA24 GA29

Claims (2)

[Claims] 1. A pulley, a shaft body which is rotatable relative to the pulley and is concentrically arranged inside the pulley, and a unidirectional direction interposed in an annular space between the pulley and the shaft body. A pulley unit including a clutch, a rolling bearing provided on both sides of the one-way clutch in the annular space, and an annular seal for sealing an outer end surface side of the rolling bearing on the free end side, the rolling bearing on the free end side Has a cage in which a projection is formed radially inward on the one-way clutch side, the annular seal is fixed to an inner peripheral surface of the pulley, and has a seal lip at its tip, A pulley unit, wherein a retaining groove into which the protrusion engages and a seal groove into which the seal lip enters are formed on an outer peripheral surface of a shaft body. 2. The pulley unit according to claim 1, wherein the seal groove has a first inner wall surface having a shape along the radial direction and a second inner wall surface having a taper shape whose groove bottom becomes shallower toward the free end side. And the seal lip is in axial contact with the first inner wall surface.