JP2004205009A - Manufacturing method for pulley - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a surface protective film from being easily separated, and to secure the anticorrosion property. <P>SOLUTION: This manufacturing method for a pulley in a pulley unit in which a one-way clutch 3 is mounted in an annular space between the pulley 1 and a rotor shaft 2, and which comprises a ball bearing 4 and a roller bearing 5 mounted at both sides of the one-way clutch in a state of sharing an inner peripheral face of the pulley as a ring raceway, includes a process for forming the surface protective film 70 of at least 15 μm -25 μm having the anticorrosion property, on the whole surface of the pulley, and a process for removing the surface protective film from the inner peripheral face of the pulley. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a pulley, and more specifically, a one-way clutch is interposed in an annular space between a pulley and a shaft body, and at least an outer raceway is provided on one side of the one-way clutch. The present invention relates to a method of manufacturing the pulley in a pulley unit provided with a rolling bearing that also serves as an inner peripheral surface. This pulley unit has a built-in one-way clutch, and can be mounted on, for example, an accessory driven from a crankshaft of an engine of an automobile or the like via a belt. Examples of the accessory include a compressor for an air conditioner of an automobile, a water pump, an alternator, a cooling fan, and the like.
[0002]
[Prior art]
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, among the auxiliary machines, for example, in the case of an alternator, if the alternator is connected so as to rotate synchronously with the crankshaft of the engine, the power generation capacity of the alternator decreases when the rotation speed of the crankshaft decreases. Therefore, the one-way clutch is incorporated in the pulley portion of the alternator, and when the rotation speed of the crankshaft decreases, the rotation of the rotor of the alternator is continued by its inertia, so that the power generation efficiency can be increased. (For example, see Patent Document 1). In addition, since various accessories mounted on an automobile engine have a problem of corrosion due to muddy water or the like, a surface protection film is often provided on a pulley portion of the alternator.
[0003]
[Patent Document 1]
JP 2001-141037 A
[Problems to be solved by the invention]
By the way, the problem in the case where the surface protective film is provided on the outer peripheral surface of the pulley as described above is that the surface protective film provided on the outer peripheral surface of the pulley is not easily peeled off. Another problem is that corrosion protection is sufficiently ensured. Yet another object is to prevent the polishing whetstone from being clogged. The present invention is to solve at least one or more of these problems.
[0005]
[Means for Solving the Problems]
A first aspect of the present invention provides a rolling bearing in which a one-way clutch is interposed in an annular space between a pulley and a shaft body, and at least one outer raceway is also used on the inner peripheral surface of the pulley on one side of the one-way clutch. A method of manufacturing the pulley in a pulley unit provided, comprising: forming a surface protective film having a corrosion resistance of 15 μm or more and 25 μm or less on the entire surface of the pulley; and forming the surface protective film from an inner peripheral surface of the pulley. And removing the.
[0006]
According to the first aspect of the present invention, since the thickness of the surface protective film is 15 μm or more, when the pulley is held by a chuck or the like, the possibility that the surface protective film is peeled off by the chuck can be avoided, and the anticorrosion property is sufficiently high. Secured. At the same time, since the film thickness of the surface protective film is 25 μm or less, when the surface protective film is removed by polishing with a polishing grindstone, clogging of the polishing grindstone does not occur. In this case, when the surface protective film is formed by cationic electrodeposition coating, the material of the coating is an organic compound and is soft, so that the polishing grindstone is likely to be clogged. Is particularly prominent.
[0007]
A second aspect of the present invention provides a rolling bearing in which a one-way clutch is interposed in an annular space between a pulley and a shaft body, and at least one of the one-way clutches has at least an outer raceway shared by an inner peripheral surface of the pulley. A method of manufacturing the pulley in a pulley unit provided with a first step of performing heat treatment on a raceway surface serving as an outer ring raceway of the rolling bearing in a pulley made of carbon steel; The method includes a second step of forming a surface protective film and a third step of removing the surface protective film formed on the raceway surface on the inner peripheral surface of the pulley.
[0008]
The heat treatment may be induction hardening for hardening at least the outer ring raceway of the rolling bearing, or carburizing and hardening for hardening the entire inner peripheral surface of the pulley.
[0009]
A rolling bearing was provided on one side of the one-way clutch to support the radial load from the pulley, and when the outer raceway of the rolling bearing also serving as the inner peripheral surface of the pulley was hardened by heat treatment, the raceway surface was distorted. State. Therefore, it is preferable that the surface protection film on the inner peripheral surface of the pulley formed in the above state and the raceway surface of the pulley that is distorted in the heat treatment step can be simultaneously removed in the removing step. That is, for example, when the inner peripheral surface of the pulley also serves as the outer raceway of the rolling bearing as in the present invention, when the surface protection film is removed in the third step, especially the inner peripheral surface of the pulley, particularly of the rolling bearing. By removing the distortion of the raceway surface serving as the outer raceway, the accurate outer raceway state of the rolling bearing can be ensured.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The details of the present invention will be described based on an embodiment shown in the drawings.
[0011]
A pulley unit into which the pulley according to the present embodiment is incorporated will be described with reference to FIGS. 1 is a longitudinal sectional view of the pulley unit, and FIG. 2 is a sectional view taken along line (2)-(2) of FIG.
[0012]
The pulley unit A has a pulley 1, a rotor shaft 2 as a shaft, a one-way clutch 3, a ball bearing 4, a roller bearing 5, annular seals 61 and 62, an annular shield plate 7, and an annular lip 8. The pulley unit A omits 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 in order to reduce the number of parts and the manufacturing cost. The shaft 2 is also used, and the outer ring is also used by the pulley 1. The pulley 1 is rotatably driven via a V-ribbed belt B by, for example, a crankshaft of an automobile engine, and has a wavy groove around which the V-ribbed belt B is wound.
[0013]
A track groove (track surface) in which the ball 41 of the ball bearing 4 composed of a deep groove ball bearing is interposed 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 into the inside of the pulley 1 as a hollow shaft body, and is fixed to an input shaft of an accessory of an automobile engine (for example, a rotor of an alternator), not shown. On an outer peripheral surface of the rotor shaft 2, flat cam surfaces 31 of the one-way clutch 3 are formed at several places around the intermediate region 2a in the axial direction, and ball bearings 4 and roller bearings are provided on both axial regions 2b and 2c. Five inner raceways are secured. An intermediate region 2a of the rotor shaft 2 is formed in an octagon, and both side regions 2b and 2c are formed in a circular shape. The outer diameter of the area 2b of the rotor shaft 2 that is the inner raceway of the ball bearing 4 is set to be larger than the outer diameter of the area 2c of the roller bearing 5 that is the inner raceway. This is because the one-way clutch 3, the ball bearing 4, and the roller bearing 5 can be easily and sequentially assembled from the shaft 2 from the axially fixed side. In a region 2b of the rotor shaft 2, a raceway groove in which the ball 41 of the ball bearing 4 formed of a deep groove ball bearing is interposed is formed.
[0014]
A circumferential groove 2d is provided in a region 2c on the free end side in the axial direction, which is set to a small diameter on the outer circumferential surface of the rotor shaft 2, and the circumferential groove 2d is provided on the inner circumferential surface of the cage 51 of the roller bearing 5 with respect to the circumferential groove 2d. The retainer 51 is positioned in the axial direction by engaging the provided radially inward annular projection 52. The one-way clutch 3 is interposed at the axial center of the opposed annular space S between the pulley 1 and the rotor shaft 2, and its inner raceway is the outer circumferential surface of the rotor shaft 2, and its outer raceway is the inner circumference of the pulley 1. It is composed of planes. The one-way clutch 3 includes an annular retainer 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 sheathed in a state of being positioned in the circumferential direction and the axial direction. On the surface, pockets 35 penetrating inward and outward in the radial direction are provided in regions corresponding to several cam surfaces 3a in the circumferential direction. An axial column 36 exists between the pockets 35 in the circumferential direction. The rollers 33 of the one-way clutch 3 are stored in the pockets 35 of the retainer 12 one by one, with the circumferential rolling range being restricted. The coil spring 34 of the one-way clutch 3 is mounted on a projection 37 protruding from the inner wall surface of each column 36 of the retainer 32, and the roller 33 is formed by the cam surface 31 and the inner peripheral surface of the pulley 1. It presses toward the narrow side (lock side) of the wedge-shaped space.
[0015]
The inner peripheral surface of the retainer 32 of the one-way clutch 3 is formed into a shape that fits into the octagonal outer peripheral surface shape of the axial intermediate region 2a of the rotor shaft 2 so that the retainer 32 is attached to the rotor shaft 2. In contrast, it is prevented from rotating in the circumferential direction. Further, the cage 32 of the one-way clutch 3 is prevented from moving toward the ball bearing 4 by a tapered step portion 2e connecting the cam surface 31 of the intermediate region 2a and the large-diameter region 2b of the rotor shaft 2. The movement toward the roller bearing 5 is sealed off by the retainer 51 of the roller bearing 5 axially positioned with respect to the rotor shaft 2. The ball bearings 4 and the bearings 5 are interposed as rolling bearings in the annular space S between the pulley 1 and the rotor shaft 2 on both sides in the axial direction of the one-way clutch 3. The ball bearing 4 has an inner ring raceway formed on the outer circumferential surface of the one axial region 2b of the rotor shaft 2 and an outer ring raceway formed on the inner circumferential surface of the pulley 1, and includes a plurality of balls 41 as rolling elements and a plurality of balls 41 as rolling elements. This is a general deep groove ball bearing comprising a crown retainer 42 for holding. The inner raceway of the roller bearing 5 is formed on the outer circumferential surface in the other axial direction region 2c of the rotor shaft 2, and the outer raceway is formed on the inner circumferential surface of the pulley 1. The plurality of rollers 53 as rolling elements and the rollers 53 are provided. It is a cage-and-roller comprising a retainer 51 for holding. In the annular space S, annular seals 61 and 62 are mounted on outer end sides of the ball bearing 4 and the roller bearing 5 in the axial direction. In each of the annular seals 61 and 62, one end of the elastic body attached to the outer periphery of the annular core is fixed to the inner peripheral surface of the pulley 1, and the other ends are formed as seal lips 61a and 62a on the outer peripheral surface of the rotor shaft 2. This is a contact form in contact. One annular seal 61 provided on the outer surface side of the roller bearing 5 at the free end side in the annular space S between the pulley 1 and the rotor shaft 2 to seal the roller bearing 5 from the outside; An annular shield plate 7 fitted on the outer periphery of the rotor shaft 2 on the outer surface side of the annular seal 61 in the annular space S between the rotor shaft 2 and the outer periphery of the annular seal 61; The operation of the pulley unit A in which the annular lip 8 that makes contact with the inner surface of the annular shield plate 7 is integrally formed is, in short, a one-way clutch according to the rotational speed difference between the pulley 1 and the rotor shaft 2. 3 is in a locked state or a free state, and transmits power from the pulley 1 to the rotor shaft 2 or shuts 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.
[0016]
In such a pulley unit A, a coating, preferably a cation-type electrodeposition coating, is formed on the outer peripheral surface and both side surfaces in the axial direction of the pulley 1 by forming a surface protective film 70 such as a corrosion-resistant property such as high rust resistance and a peeling resistance. As a result, the inner peripheral surface is not formed as a result of the removal of the surface protective film 70 by removal processing such as polishing. Note that the surface protective film 70 shown in FIGS. 1 and 2 is exaggerated compared to the actual film thickness for the purpose of clarifying and understanding the formation location.
[0017]
A method of manufacturing the pulley 1 according to the present embodiment will be described with reference to FIGS. FIG. 3 schematically shows a manufacturing process of the pulley 1, and FIG. 4 is a cross-sectional view of a main part of the pulley 1 showing a state in which the entire surface of the pulley 1 is coated with the surface protection film 70 by the coating process of FIG. 5 is a cross-sectional view of a main part of the pulley, showing a state where the surface protection film 70 has been removed from the inner peripheral surface of the pulley 1 by the polishing step of FIG.
[0018]
By the turning process of FIG. 3, the pulley 1 is made of carbon steel. The pulley 1 is turned into a required shape in a turning process. After this turning, heat treatment is performed. In this case, the carbon steel as the material of the pulley 1 is subjected to plastic working in a warm or sub-warm temperature range, and then heat-treated. In this heat treatment, since the inner peripheral surface of the pulley 1 also serves as the outer raceway of each of the ball bearing 4, the one-way clutch 3, and the roller bearing 5, as described above, each raceway portion is hardened by induction hardening. The hardened layer is not shown.
[0019]
On the entire surface of the pulley 1 (outer peripheral surface, inner peripheral surface, both side surfaces in the axial direction), after the heat treatment step, a process of forming a corrosion-resistant surface protective film 70 is performed. This process is a coating process using cationic electrodeposition coating. The film thickness of the surface protective film 70 is 15 μm or more and 25 μm or less. Cationic electrodeposition coating is a coating technique in which a negative voltage is applied to a pulley 1 which is a coated object, and a positively polarized paint is deposited on the surface of the pulley 1 to form a coating film. A detailed description of the film thickness control by this coating is omitted.
[0020]
When the film thickness of the surface protection film 70 is 15 μm or more, it is possible to avoid the possibility that the surface protection film 70 is peeled off when the outer peripheral surface side of the pulley 1 is held by the chuck 71, and it is possible to secure the corrosion protection. When the thickness of the surface protective film 70 is 25 μm or less, the polishing grindstone 72 does not become clogged when the surface protective film 70 is removed from the inner peripheral surface of the pulley 1 using the polishing grindstone 72. .
[0021]
Such a cationic electrodeposition coating uses an organic compound as a component of a coating material, and specific coating materials include an anticorrosive material mainly composed of epoxy resin, acrylic resin, nylon 66, or the like. This cationic coating does not contain heavy metals and is therefore environmentally friendly, can be cured at an extremely low temperature, and has high corrosion resistance and high rust resistance.
[0022]
Instead of the cationic electrodeposition coating, the surface protective film 70 may be formed by zinc plating. Since zinc constituting the surface protective film 70 has a lower potential than iron constituting the main body of the pulley 1, the corrosion of the main body is prevented by sacrificial anticorrosion. Since galvanizing itself is well known, a detailed description of the galvanizing method is omitted.
[0023]
After such a coating step, polishing for removing the surface protective film 70 formed on the inner peripheral surface of the pulley 1 is performed. In this polishing step, the inner surface of the pulley 1 is polished with a polishing grindstone 72 to remove the surface protective film 70 from the inner surface as shown in FIG.
[0024]
When removing the surface protective film 70, a portion of the inner peripheral surface of the pulley 1 which is also used as the outer raceway of the ball bearing 4 and is distorted by the heat treatment may be removed at the same time.
[0025]
As described above, the coated and polished pulley 1 is provided with the surface protection film 70 having high anticorrosion properties and being hard to peel off on the outer peripheral surface and on both axial side surfaces. In the polishing step, portions of the inner peripheral surface of the pulley 1 that are hardened and distorted by heat treatment on the outer raceways of the ball bearing 4, the one-way clutch 3, and the roller bearing 5 are also removed at the same time. This is preferable because distortion of the outer raceway can be removed.
[0026]
The present invention can be applied to at least all the pulley units in which the outer raceway of the ball bearing 4 on one side in the axial direction of the one-way clutch 3 is also used for the inner peripheral surface of the pulley 1. That is, in the present invention, for example, both the outer raceway of the one-way clutch 3 and the outer raceway of the ball bearing 4 on one axial side of the one-way clutch 3 are shared by the inner peripheral surface of the pulley 1. The roller bearing 5 on the other side in the axial direction of the one-way clutch 3 itself has an outer ring, and the present invention can be applied to a pulley unit in which the inner peripheral surface of the pulley 1 does not double as the outer ring raceway. Further, according to the present invention, unlike the above-described embodiment, there is no roller bearing 5 on the other axial side of the one-way clutch 3, and the one-way clutch 3 is arranged so as to be packed on one axial free end side of the shaft body 1. The present invention can be similarly applied to a pulley unit in which the ball bearing 4 is disposed on the other base side in the axial direction. In the case of such a pulley unit as well, the surface protective film 70 is formed on the outer peripheral surface of the pulley 1 in the same manner as in the above-described embodiment, while the surface protective film 70 is removed from the inner peripheral surface of the pulley 1. I have.
[0027]
【The invention's effect】
As described above, according to the present invention, it is possible to avoid the possibility that the surface protective film is easily peeled off, and at the same time, it is possible to secure the anti-corrosion property, and to use a processing tool such as a grinding wheel from the inner peripheral surface of the pulley. When the surface protective film is removed by the process, the processing tool is less likely to be clogged.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a pulley unit according to an embodiment of the present invention. FIG. 2 is a sectional view taken along a line (2)-(2) in FIG. 1. FIG. 4 is a cross-sectional view of a main part of the pulley, showing a state where a surface protection film is coated on the entire surface of the pulley by the coating step of FIG. 3; Sectional view of main part of pulley showing state in which film is removed.
Reference Signs List A Pulley unit B Belt S Annular space 1 Pulley 2 Rotor shaft 3 One-way clutch 4 Ball bearing 5 Roller bearing 6 Annular seal 7 Annular shield plate 8 Annular lip 70 Surface protective film

Claims (4)

A one-way clutch is interposed in the annular space between the pulley and the shaft body, and a pulley unit including a rolling bearing on at least one side of the one-way clutch that also serves as at least an outer raceway on the inner peripheral surface of the pulley. A method of manufacturing a pulley,
Forming a surface protective film having an anticorrosive property of 15 μm or more and 25 μm or less on the entire surface of the pulley;
Removing the surface protective film from the inner peripheral surface of the pulley;
A method for manufacturing a pulley, comprising: The method for manufacturing a pulley according to claim 1,
A method for manufacturing a pulley, wherein the surface protective film is formed by cationic electrodeposition coating. A one-way clutch is interposed in the annular space between the pulley and the shaft body, and a pulley unit including a rolling bearing on at least one side of the one-way clutch that also serves as at least an outer raceway on the inner peripheral surface of the pulley. A method of manufacturing a pulley,
A first step of performing heat treatment on a raceway surface serving as an outer raceway of the rolling bearing in a pulley made of carbon steel;
A second step of forming a corrosion-resistant surface protective film on the entire surface of the pulley;
A third step of removing a surface protective film formed on the raceway surface on the inner peripheral surface of the pulley;
A method for manufacturing a pulley, comprising: The method for manufacturing a pulley according to claim 3,
The method of manufacturing a pulley according to claim 3, wherein the third step is to remove the surface protective film together with a strained portion of the raceway surface of the pulley due to the heat treatment.

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