JP4706252B2 - Pulley manufacturing method - Google Patents

Description

  The present invention relates to an improvement of a press pulley idler bearing unit mainly used for supporting an automobile engine accessory belt, or a press pulley tensioner bearing unit for applying belt tension.

Conventionally, for example, a cast product and a machined machined product have been used for this kind of pulley used for supporting a belt of an automobile engine auxiliary machine (generator, cooler compressor, etc.).
In recent years, automobiles have become increasingly smaller in size and engine room to improve fuel efficiency, and are manufactured by press molding, which is more advantageous than cast products and machined cut products in terms of weight and productivity. There is an increasing demand for press pulleys (press forming pulleys) (see, for example, Patent Document 1).

Conventionally, most of such press pulleys have been subjected to surface treatment (plating treatment) for the purpose of preventing rust.
Here, a conventional manufacturing process of the press pulley will be described. FIG.1 (b) shows the outline of the process drawing of the conventional pulley manufacturing method.
Conventionally, a press pulley is first formed into a flat plate shape as a forming material (S-1a), and the forming material is punched into an annular shape having a shaft hole at the center (S-1b) (pretreatment step) S-1).
Then, after the pretreatment step, a cylindrical fitting portion that fits and accommodates the bearing outer ring is recessed around the shaft hole of the annularly processed molding material (S-2a), and the outer periphery is substantially omitted. A belt receiving portion which is bent in the horizontal direction and is continuous in the circumferential direction is formed (S-2b) (pressing step S-2).
And after press-molding in this way, surface treatment processing (plating treatment S-3) was performed on the molded product 100. Thereafter, a press outer bearing unit is formed by press-fitting a bearing outer ring into the fitting portion (S-4).
This surface treatment is not a barrel plating method that may cause deformation or scratches in order to minimize the occurrence of scratches on the pulley exterior and to avoid deformation due to collision between pulleys, but is shown in FIG. Surface treatment is performed by immersing the press-molded product 100 in the processing agent by a one-rack system in which the molded product 100 press-molded in such a form is immersed in the processing agent.
Patent Publication 2002-250429

However, in the case of the rack system, because of the pulley shape, as shown in FIG. 7, an air pocket called an air pocket is generated when immersed in the processing agent, and the processing agent does not adhere to that portion. There exists a fault that the process part (henceforth, air pocket) 200 generate | occur | produces.
The occurrence of such an air pocket 200 is a factor that leads to the following problems.
That is, in the current surface treatment process, due to the presence of the air pocket 200, the roundness shape collapses by the plating thickness, and this often affects the roundness collapse of the bearing outer ring to be press-fit. There is a problem. The roundness of the outer ring of the bearing needs to be as small as possible so that the roundness of the bearing outer ring does not collapse because it causes abnormal noise and shortens the service life.
Furthermore, the rack method has a demerit that costs are increased due to the increased man-hours.
The present invention has been made in view of the above-described problems of the prior art. The object of the present invention is to provide a pulley used in a press pulley bearing unit that is free from collapse of roundness due to surface treatment and is inexpensive. Is to provide.

The technical means made by the present invention in order to achieve such an object are as follows.
1st invention is the manufacturing method of the pulley bearing unit for automobile engine auxiliary machine belt support using the pulley shape | molded by press molding, Comprising: The process of carrying out the rolling shaping | molding of a steel plate, and forming in flat form, A pulley bearing A step of plating the entire plate-like steel plate so that the thickness of the plating layer when completed as a unit is 5 to 20 μm, and punching the plate-like steel plate after the plating treatment, and a shaft hole at the center Forming a ring-shaped molding material having a step, recessing a cylindrical fitting portion that fits and accommodates the bearing outer ring around the shaft hole in the ring-shaped molding material, and the outer circumference of the ring substantially horizontally. The automobile engine auxiliary bell has a step of forming a belt receiving portion that is bent in the direction of the belt and a circumferentially continuous belt receiving portion, and a step of press-fitting the outer ring of the bearing into the cylindrical fitting portion. Resides in that the manufacturing method of the support pulley bearing unit.
A second invention is a method of manufacturing a pulley bearing unit for supporting an automobile engine accessory belt using a pulley formed by press molding, the step of rolling a steel plate to form a flat plate, A step of punching a steel plate to form an annular molding material having a shaft hole in the center, and a thickness of a plating treatment layer when completed as a pulley bearing unit is 5 to 20 μm. The process of plating the whole, the process of recessing a cylindrical fitting part that fits and accommodates the bearing outer ring around the shaft hole in the plated annular molding material, and the outer periphery of the ring is substantially And a step of forming a belt receiving portion that is bent in the horizontal direction to form a belt receiving portion continuous in the circumferential direction, and a step of press-fitting a bearing outer ring into the cylindrical fitting portion. It resides in that the method for manufacturing a belt supporting pulley bearing unit.
A third invention is the belt according to the first invention or the second invention, wherein the die and the pulley are rotated together while pressing the die against the outer peripheral surface of the belt receiving portion formed continuously in the circumferential direction. And having a step of forming a V-groove in the receiving portion.
The fourth invention is that in the step of plating, the forming material is plated with a surface treatment agent containing Zn, Al, Zn ₂ Hg.

According to the present invention, since the surface treatment is performed on the material before being press-molded, no air pockets are generated, and the roundness collapse due to the surface treatment does not occur.
Further, the surface treatment of the material before press forming is often performed in-line after the steel plate rolling process, and the cost can be reduced as compared with the rack method.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, this embodiment is only one embodiment of the present invention, and is not construed as being limited thereto. The design can be changed within the scope of the present invention. FIG. 1A is a process diagram showing an outline of the manufacturing process of the press pulley bearing of the present invention, FIG. 2 is a schematic diagram showing the manufacturing process of the press pulley of the present invention, and FIG. 3 is a press shown in Example 1 of the present invention. 4 is a schematic cross-sectional view showing a partially enlarged view of FIG. 3, FIG. 5 is a schematic vertical cross-sectional view of a press pulley bearing shown in Example 2, and FIG. The schematic sectional drawing which shows the process of processing V groove | channel on the outer periphery of a press pulley is shown.

"Example 1"
FIG. 3 is a schematic cross-sectional view showing a first embodiment of a press pulley bearing unit in which a rolling bearing 8 is incorporated by fitting an outer ring 9 into a bearing fitting portion 2 of a press-molded pulley 1.

  The pulley 1 used in the press pulley bearing unit of the present invention is formed in an overall cylindrical shape including a cylindrical bearing fitting portion 2 having one side 5 opened and the other side 6 recessed in the axial direction, The outer peripheral surface is a belt receiving portion 4 having a flat plate shape in cross section in the circumferential direction, and a shaft hole 3 opening in the axial direction is formed at the center of the bottom portion 2a of the bearing fitting portion 2.

  The rolling bearing 8 holds a pair of relatively rotatable bearing rings (an outer ring 9 and an inner ring 10), a plurality of rolling elements 11 incorporated between the outer ring 9 and the inner ring 10, and the respective rolling elements 11. A deep groove ball bearing is illustrated as an example, which includes a retainer (not shown) and a sealing plate (not shown) spanned between the pair of race rings 9 and 10. The rolling bearing 8 incorporated in the pulley 1 of the present embodiment is not limited to the illustrated example, and can be changed in design within the scope of the present invention.

  FIG. 1A is a schematic diagram showing a process diagram of a method for manufacturing a press pulley of the present invention, and FIG. 2 is a schematic diagram showing a process of manufacturing the press pulley, in which a pretreatment process S-1 and a press process S- The present invention is characterized in that the surface treatment is performed in the pretreatment step S-1. Hereinafter, an embodiment of the production process of the present invention will be described.

"Pretreatment step S-1"
This step is a step of forming the molding material M-1 to be press-molded, and the molding material M-1 is first formed by rolling a steel plate to form a flat plate (S-1a).

Next, surface treatment is applied to the flat steel plate M that has been rolled as described above (S-1b).
This surface treatment is a step of plating the entire flat steel plate M with a surface treatment agent containing Zn, Al, Zn ₂ Hg or the like, as described above. In consideration of peeling, it is configured to be thicker than the thickness (for example, 5 to 20 μm in this embodiment) of the plating layer P that needs to be provided as a molded product. Further, in this embodiment, the surface treatment processing (plating treatment) is performed as it is in-line after the step of rolling the steel plate into a flat plate, so that the cost is low.
The reason why the thickness of the plating layer P of the molded product is set to 5 to 20 μm, for example, is that it is difficult to make the thickness thinner than 5 μm and uniform, and the thickness higher than 20 μm increases the cost.
Accordingly, the plating layer P is initially configured to be thick as described above, but it is uniformly thinned through the pressing step S2 and has a thickness of about 5 to 20 μm.
The material for the surface treatment agent is not particularly limited, but is preferably a material having a high rust prevention effect.

Next, the flat steel plate M after the surface treatment is punched, and a forming material M-1 is formed into an annular shape (a donut-shaped disc shape) having a shaft hole 3 at the center (S-1c). .
Note that the punching shape of the molding material M-1 formed by this process is formed in consideration of the size of the press pulley to be press-molded. Further, one or a plurality of doughnut-shaped forming materials M-1 are punched from the flat steel plate M. At the time of punching, care should be taken so that the yield is low.

"Pressing process S-2"
This step is a step of press-molding the doughnut-shaped molding material M-1 molded in the pretreatment step to obtain a molded product, which is first processed into the donut shape after the pretreatment step S-1. A cylindrical fitting portion 2 that fits and accommodates the bearing outer ring 9 around the shaft hole 3 is recessed in the molding material M-1 (S-2a).
Various conditions such as the depth and the inner diameter of the fitting portion 2 are only required to allow the outer ring 9 of the rolling bearing 8 to be fitted, and the design can be changed as appropriate according to the implementation conditions.

Next, the outer periphery of the ring is bent in a substantially horizontal direction to form a belt receiving portion 4 continuous in the circumferential direction (S-2b).
Various conditions such as the width in the depth direction of the belt receiving portion 4 can be appropriately changed according to the conditions of implementation.

  Then, a bearing outer ring 9 is press-fitted into the fitting portion 2 to form a press pulley bearing unit (S-3).

Although not shown in the drawings in the present embodiment, well-known rolling devices, press dies, and the like are appropriately selected and used for the pretreatment step and the pressing step within the scope of the present invention.
Moreover, according to the present Example, since the annular punching process (molding material M-1 molding process) and the press work process can be performed on the same line after the surface treatment process described above, work efficiency is improved.

Further, the press pulley 1 of this embodiment is also characterized by having the following configuration (see FIG. 4).
That is, in this embodiment, taking a large upper edge R ₂ of the fitting portion 2 is configured to maintain the roundness prevent stress concentration.
Incidentally, when the upper edge R ₂ of the fitting portion 2 is too large the fitting surface of the bearing outer ring 9 (flat surface B) is reduced, it is not preferable because the load bearing decreases.
The relationship between flat surface B is a flat portion A and the belt-receiving surface is a mating surface, in order to affect the power transmission belt, the thickness of the upper edge R ₁ and the belt receiving portion 4 of the belt receiving portion 4 The ratio of t affects the force required during pressing. That, a larger upper edge R ₁ of the belt receiving portion 4 is advantageous over the press forming, is too large, flat surface A of the belt receiving portion 4 becomes small.

Therefore, specifically, the following values are desirable. In the following description, A is the length of the flat surface A, B is the length of the flat surface B, t is the thickness of the belt receiving portion, and R ₁ is the size of the upper edge R ₁ of the belt receiving portion.
B / A = 0.3-1.0
t = 1.7-3.2 mm
R ¹ /t=0.4 to 1.5

In addition, according to a present Example, since the plate-shaped steel plate M is surface-treated, the shaft hole 3 and the whole annular punching process are shape | molded, and the shaping | molding raw material M-1 is shape | molded, Therefore The edge (end surface 3a) and the end edge (end surface 4a) of the belt receiving portion 4 are not subjected to surface treatment, but the coating is formed by Zn, Al, Zn ₂ Hg dissolved out from the surface treatment layer (plating treatment layer P). Since it is formed, there is no particular problem. Further, since the pulley 1 rotates, water droplets and the like can be blown off by centrifugal force, so there are few adverse effects caused by the untreated end surfaces 3a.
Furthermore, it is also possible within the scope of the present invention to separately treat the end surface 3a of the shaft hole 3 and the end surface 4a of the belt receiving portion 4.

In this embodiment, as described above, surface treatment is performed at the stage of the flat steel plate M, but the present invention is in a state of being punched into a material before being transferred to press forming, for example, a donut shape. The molding material M-1 may be surface-treated and is optional.
With this configuration, the surface treatment is performed after punching into a donut shape, and thus the end surface 3a of the shaft hole 3 and the end surface 4a of the belt receiving portion 4 are simultaneously surface-treated as described above.
In addition, the donut-shaped disc shape after punching is not limited to one that is completely punched from the steel plate and separated one by one, and at least a part is connected and not completely separated It is also possible to subject the material in such a state to surface treatment.

According to the present embodiment configured as described above, the bearing roundness after being press-fitted into the fitting portion 2 of the pulley 1 can be made smaller than 0.007 mm. Can be improved.
"Example 2"

5 and 6 show another embodiment of the press pulley of the present invention.
This embodiment is a V-belt vehicle that performs power transmission by bridging a V-belt having a plurality of V-grooves, and is provided with a plurality of V-grooves 7 that are continuous in the circumferential direction on the surface of the belt receiving portion 4. It is an example of a press pulley called a pulley.
Since manufacturing steps other than the step of manufacturing the V-groove 7, other configurations and operational effects are the same as those in the first embodiment, the details thereof are omitted.
That is, after passing through the manufacturing process (S1 and S2) similar to Example 1, while pressing the type | mold F shown in FIG. 6 against the outer peripheral surface of the belt receiving part 4 of the pulley 1, both the type | mold F and the pulley 1 are rotated, The V groove 7 is formed.
According to the present embodiment, since this V-groove manufacturing process is not cutting, the plating layer P is not extremely peeled off, and a desired roundness can be obtained.

(A) is process drawing which shows the outline of the manufacturing process of the press pulley bearing of this invention, (b) is process drawing which shows the outline of the manufacturing process of the prior art press pulley bearing. Schematic which shows the manufacture process of the press pulley of this invention. 1 is a schematic longitudinal sectional view of a press pulley bearing shown in Embodiment 1 of the present invention. FIG. 4 is a schematic cross-sectional view showing a partially enlarged view of FIG. 3. FIG. 4 is a schematic longitudinal sectional view of a press pulley bearing shown in Embodiment 2. FIG. 6 is a schematic cross-sectional view showing a step of processing a V groove on the outer periphery of the press pulley of Example 2. Schematic which shows the surface treatment processing state of a prior art press pulley.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulley 2 Bearing fitting part 3 Shaft hole 4 Belt receiving part 8 Rolling bearing M Flat steel plate M-1 Forming material P Surface treatment layer (plating layer)

Claims (4)

A method of manufacturing a pulley bearing unit for supporting an automobile engine auxiliary machine belt using a pulley formed by press molding,
Rolling and forming a steel plate to form a flat plate;
Plating the entire plate-shaped steel sheet so that the thickness of the plating layer when completed as a pulley bearing unit is 5 to 20 μm;
A step of punching a plate-shaped steel plate after plating, and forming an annular molding material having a shaft hole in the center;
A step of recessing a cylindrical fitting portion for fitting and housing the bearing outer ring around the shaft hole in an annular molding material;
Bending the annular outer periphery in a substantially horizontal direction to form a belt receiving portion continuous in the circumferential direction;
Press fitting the outer ring of the bearing into the cylindrical fitting portion;
A method of manufacturing a pulley bearing unit for supporting an automobile engine accessory belt, comprising: A method of manufacturing a pulley bearing unit for supporting an automobile engine auxiliary machine belt using a pulley formed by press molding,
Rolling the steel plate to form a flat plate;
A step of punching a flat steel plate to form an annular molding material having a shaft hole in the center;
Plating the whole of the molding material so that the thickness of the plating layer when completed as a pulley bearing unit is 5 to 20 μm;
A step of recessing a cylindrical fitting portion that fits and accommodates a bearing outer ring with the shaft hole as a center in a plated annular molding material;
Bending the annular outer periphery in a substantially horizontal direction to form a belt receiving portion continuous in the circumferential direction;
A step of press-fitting a bearing outer ring into the cylindrical fitting portion;
A method of manufacturing a pulley bearing unit for supporting an automotive engine accessory belt, comprising: The method further comprises a step of forming a V-groove in the belt receiving portion by rotating both the die and the pulley while pressing the die against the outer peripheral surface of the belt receiving portion formed continuously in the circumferential direction. A method of manufacturing a pulley bearing unit for supporting an automobile engine accessory belt according to claim 1. The automotive engine auxiliary belt support according to any one of claims 1 to 3, wherein the plating process is performed with a surface treatment agent containing Zn, Al, Zn ₂ Hg. Manufacturing method of pulley bearing unit.

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