JP5861270B2 - Manufacturing method of resin pulley - Google Patents

Description

The present invention relates to a method of manufacturing a resin pulley integrally formed on the outer peripheral surface of an outer ring of a bearing. More specifically, the present invention relates to a drive belt pulley, a belt tensioner pulley, an idler pulley, etc. preferably a method for producing a resin pulleys that can be used.

  The pulleys described above were conventionally made of metal, but as a resin pulley with a pulley body made of resin and a rolling bearing built into the inner periphery in order to reduce the size and weight of automobile parts and reduce costs. Increasing use.

  FIG. 1 is a cross-sectional view showing an example of a resin pulley integrated with a rolling bearing, and FIG. 2 is a side view, but the rolling bearing 10 is provided between an outer ring 11, an inner ring 12, and an outer ring 11 and an inner ring 12. A plurality of balls (rolling elements) 13 that are movably disposed, a retainer 14 that holds the balls 13 at equal intervals in the circumferential direction, and an inner circumferential portion of both ends in the axial direction of the outer ring 11 are mounted on the bearing space. And a sealing member 15 for sealing between the outside and the outside.

  A resin pulley 20 is integrally formed on the outer peripheral surface of the outer ring 11. The resin pulley 20 includes an inner cylinder part 21 that is integrally fixed to the outer peripheral surface of the outer ring 11 in an externally fitted state, an outer cylinder part 22 that is disposed concentrically with the inner cylinder part 21, and an outer cylinder part 22 and an inner cylinder. A plate-shaped central annular plate 23 that connects the portion 21, and reinforcing ribs 24 that are radially disposed on both surfaces of the central annular ring 23 and connect the inner cylindrical portion 21 and the outer cylindrical portion 22. . A belt (not shown) that drives an auxiliary machine of an automobile engine, a camshaft, and the like is stretched around the outer cylinder portion 22.

  The resin pulley 20 is generally manufactured by injection molding using a die having a cavity that matches the outer shape of the resin pulley 20 and using the rolling bearing 10 as a core. In injection molding, the resin pulley 20 is injected from the gate. The formed molding material associates in the cavity of the mold, and this associated portion appears as a weld portion on the resin pulley 20. As the molding material, a resin composition in which a fibrous reinforcing material is blended with a resin is used. However, in this weld part, the fibrous reinforcing materials collide with each other and the orientation state differs from other parts, resulting in low mechanical strength. Become.

  Therefore, in Patent Document 1, for the purpose of improving the strength at the weld portion, the orientation state of the fibrous reinforcing material in the injected resin composition is made uniform by providing a gate at a position corresponding to between the ribs of the resin pulley 20. I suggest that you do.

  FIG. 9 is a schematic view of a cross section of a part of the resin pulley 20 of Patent Document 1 cut along a plane orthogonal to the axis. In the inner cylinder part 21 and the outer cylinder part 22, most of the fibrous reinforcing material 35 is formed. The inner cylinder part 21 and the outer cylinder part 22 are oriented in the thickness direction (direction orthogonal to the circumferential direction). In the figure, the gate position is indicated by reference numeral 40. When the resin pulley 20 is subjected to severe thermal stress such as a sudden temperature change (heat shock state), the inner cylindrical portion 21 of the resin pulley 20 is rolled by the difference in linear expansion coefficient between the resin and the bearing material. The outer ring 11 expands or contracts with respect to the outer peripheral surface of the outer ring 11, so that the creep property is reduced due to the expansion or the damage is easily caused by the contraction. Therefore, like the resin pulley 20 of Patent Document 1, if the fibrous reinforcing material 35 is oriented in the thickness direction of the inner cylinder portion 21, it cannot sufficiently cope with the expansion and contraction of the inner cylinder portion 21 in the circumferential direction. .

JP-A-4-34260

  Therefore, an object of the present invention is to provide a resin pulley that is excellent in the effect of suppressing expansion and contraction in the circumferential direction of the inner cylinder portion when subjected to severe thermal stress and excellent in thermal stability.

The present invention for the purpose provides a manufacturing method of the following resin pulley.
( 1 ) An inner cylinder made of a resin composition in which a fibrous reinforcing material is blended with a resin, and an inner cylinder portion that is in contact with the outer peripheral surface of the outer ring of the bearing; And a plate-shaped central annular part that connects the inner cylindrical part and the outer cylindrical part, and ribs that are arranged radially on the central annular part and connect the inner cylindrical part and the outer cylindrical part. In the manufacturing method of the resin pulley molded integrally with the bearing,
There are locations corresponding to the inner cylindrical portion corresponding to the inner cylindrical portion of the resin pulley, locations corresponding to the outer cylindrical portion corresponding to the outer cylindrical portion, locations corresponding to the rib corresponding to the ribs, and locations corresponding to the central annular portion corresponding to the central annular portion. And having a cavity whose circumferential width is larger than the interval between the central ring portions, the central circle between all adjacent rib portions corresponding to the central ring portion of the cavity. A column part having a boundary between the ring-corresponding portion and the inner tube portion-corresponding portion as a part of the outer periphery is formed so as to penetrate the central annular portion phase portion in the thickness direction. A method for producing a resin pulley, characterized in that a resin composition is injection-molded using a formed mold and a bearing as a core.
( 2 ) The method for producing a resin pulley according to the above ( 1 ), wherein the gate is provided at a position corresponding to the inner cylinder portion, at a position dividing the position corresponding to the inner cylinder portion into at least eight equal parts.

According to the present invention , since the fibrous reinforcing material is oriented in the circumferential direction of the inner cylinder portion in the obtained resin pulley, the circumferential direction is more than the case where the fibrous reinforcing material is oriented in the thickness direction of the resin pulley. Expansion and contraction are suppressed, and deterioration of creep properties and damage can be prevented.

It is sectional drawing which shows an example of a rolling bearing integrated resin pulley. It is a side view of FIG. It is a figure which shows the orientation state of the fibrous reinforcement in the resin pulley obtained by this invention , and is sectional drawing which cut | disconnects and shows a part of resin pulley in the surface orthogonal to an axis. It is a figure for demonstrating how to obtain | require the fibrous reinforcing material orientated in the circumferential direction of the inner cylinder part of a resin pulley. In the present invention is a diagram showing a part of a mold cavity used to produce the resin pulley. It is a figure which shows the state which formed the pillar part in the metal mold | die according to FIG. It is sectional drawing which shows the rolling bearing integrated resin pulley obtained by this invention according to FIG. FIG. 8 is a side view of FIG. 7. It is a figure which shows the orientation state of the fibrous reinforcement in the resin pulley of patent document 1, and is sectional drawing which cut | disconnects and shows a part of resin pulley in the surface orthogonal to an axis.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

The resin pulley obtained by the manufacturing method of the present invention can present the resin pulley 20 having the configuration shown in FIGS. 7 and 8, and the column portion 50 (see FIG. 6) on the central annular portion 23 of the resin pulley 20. The through-hole 60 corresponding to is formed. The through hole 60 is formed between all the adjacent ribs 24 and partially overlaps the boundary between the inner cylindrical portion 21 and the central annular portion 23. As shown in FIG. 3, in the resin pulley 20 of the present invention, in the inner cylinder portion 21, most of the fibrous reinforcing material 35 is oriented in the circumferential direction of the inner cylinder portion 21. Specifically, the fibrous reinforcing material (indicated by reference numeral 35A) oriented in the circumferential direction of the inner cylinder portion 21 is aligned with the fibrous reinforcing material (indicated by reference numeral 35B) in the thickness direction of the inner cylindrical portion 21. There are more than. Ideally, all of the fibrous reinforcing materials are oriented in the circumferential direction, but in reality, there is a fibrous reinforcing material 35B oriented in the thickness direction, so that it is oriented in the circumferential direction. It is preferable that the fibrous reinforcing material 35A is present at 30% or more of the entire fibrous reinforcing material. In the conventional resin pulley, the fibrous reinforcing material 35A oriented in the circumferential direction is about 10% of the entire fibrous reinforcing material, and according to the present invention, the fibrous reinforcing material 35A oriented in the circumferential direction is greatly increased. Can be increased.

  In order to verify the blended state of the fibrous reinforcing material 35 as described above, the resin pulley 20 is cut perpendicularly to the axial direction as shown in FIG. The region (the part surrounded by the symbol X in the figure) is set as the observation range, observed with a metal microscope at 5 to 20 times to observe the orientation state of the fibrous reinforcing material, and the circumferential direction (field of view) of the inner cylinder part 21 The ratio of the fibrous reinforcing material 35A oriented in the left-right direction) is determined. Although the gate is indicated by reference numeral 40, as will be described later, the gate 40 is provided at an appropriate position directly below the rib 24 of the inner cylinder portion 21, preferably at a position where the inner cylinder portion 21 is divided into at least eight equal parts.

  In addition, although the outer cylindrical portion 22 includes the fibrous reinforcing material 35 oriented in the circumferential direction, there is no specification of the orientation ratio as described above in the inner cylindrical portion 21.

In order to realize the above-mentioned orientation state of the fibrous reinforcing material 35 in the inner cylinder portion 21, a mold having the cavity 20A shown in FIG. 5 (however, only the cavity is omitted) and the resin composition is injection molded. To do. FIG. 5 shows a part of the cavity corresponding to FIG. The illustrated cavity 20 </ b> A is a space corresponding to the outer shape of the resin pulley 20, i.e., an inner cylinder portion equivalent portion 21 </ b> A corresponding to the inner cylinder portion 21 of the resin pulley 20 and an outer cylinder portion equivalent portion corresponding to the outer cylinder portion 22. 22A, a central annular portion equivalent portion 23A corresponding to the central annular portion 23, and a rib equivalent portion 24A corresponding to the rib 24 are continuous voids, and the mold further includes an inner cylindrical portion equivalent portion 21A. A plurality of gates 40 are provided at predetermined intervals immediately below the rib equivalent portion 24A. The injected resin composition flows in the cavity 20A as indicated by an arrow, but when flowing in the inner cylinder portion corresponding portion 21A, a fibrous reinforcing material (not shown) along the circumferential direction that is the flow direction. Become oriented.

At this time, the central annular portion of the cavity 20A is set such that the circumferential width B (see FIG. 2) of the rib 24 is larger than the thickness A (see FIG. 1) of the central annular portion 23 of the resin pulley 20. The thickness of the equivalent portion 23A and the circumferential width of the rib equivalent portion 24A are set. With such a dimension setting, as shown in FIG. 5 , the resin composition from the gate 40 has a flow portion a toward the rib equivalent portion 24 </ b> A and a flow portion b toward the inner cylinder portion equivalent portion 21 </ b> A. As a result, the proportion of the fibrous reinforcing material 35 oriented in the circumferential direction of the inner cylinder portion 21 in the resin pulley 20 increases.

  In addition, it is preferable that the width B is 1.0 to 2.0 times the thickness A in the magnitude relationship between the thickness A of the central annular portion 23 and the circumferential width B of the rib 24. When the width B is less than 1.0 times the wall thickness A, the proportion of the fibrous reinforcing material 35 oriented in the circumferential direction of the inner cylinder portion 21 decreases. On the other hand, when the width B is larger than 2.0 times the thickness A, the central annular portion 23 becomes too thin, which is not preferable in terms of strength.

  Moreover, as shown in FIG. 6, the inner cylinder part 21 is provided between the rib equivalent part 24A and the rib equivalent part 24A by providing the mold with a column part 50 that penetrates the central annular part 23A in the thickness direction. The fibrous reinforcing material 35 oriented in the circumferential direction can be increased. The column portion 50 is provided such that a part of the outer peripheral surface thereof is in contact with the boundary Y between the inner cylinder portion equivalent portion 21A and the central annular portion equivalent portion 23A. The column portion 50 obstructs the flow of the resin composition from the gate 40 to the central annular portion equivalent portion 23A, and as a result, the flow b to the inner cylindrical portion equivalent portion 21A increases, and the resin pulley 20 The fibrous reinforcing material 35 oriented in the circumferential direction of the inner cylinder portion 21 is increased.

  The gate 40 is preferably provided at a position that divides the inner cylindrical portion equivalent portion 21A into at least eight equal parts in the circumferential direction. As the number of gates 40 increases, the number of meeting portions of the resin composition increases, so the chance of collision between the fibrous reinforcing materials at the meeting portions increases, and the fibrous reinforcing material oriented in the thickness direction of the inner cylindrical portion corresponding portion 21A. Will increase. Therefore, it is appropriate that the gate 40 is installed so as to divide the portion 21A corresponding to the inner cylinder portion into a maximum of 16 portions in the circumferential direction.

  Although there is no restriction | limiting also in the resin composition in this invention, For example, what mix | blended glass fiber as the fibrous reinforcement 35 in the polyamide resin and the polyphenylene sulfide resin can be used. As the polyamide resin, polyamide 66 which is excellent in strength and heat resistance is preferable. However, since it is assumed that it is in contact with water in an automobile engine accessory, low water-absorbing polyamide such as polyamide 12, polyamide 11, polyamide 612 and polyamide 610 is used. More preferably, it contains a resin. In order to enhance the compatibility between the polyamide 66 and the low water-absorbing polyamide resin, an amorphous aromatic polyamide resin may be blended. Furthermore, rubbery substances such as ethylene propylene non-conjugated diene rubber (EPDM) that improves impact resistance may be blended.

  As the glass fiber, in addition to glass fibers having a circular cross section, glass fibers having an irregular cross section such as an eyebrow shape, an ellipse, and an ellipse can be used. In particular, a glass fiber having a deformed cross-section having a deformed ratio (ratio of a major axis portion to a minor axis portion) of 1.5 to 5 is preferable. Glass fibers having an irregular cross section are less likely to break than glass fibers having a circular cross section, and are dispersed in the resin in a longer state than glass fibers having a circular cross section when injection molded. In addition, glass fiber is surface-treated with a silane coupling agent having an epoxy group or amino group at one end, or a sizing agent such as epoxy, urethane, or acrylic in consideration of adhesiveness to the resin. Is preferably used.

  Further, a part of the glass fiber can be replaced with another fibrous reinforcing material such as carbon fiber or a whisker-like reinforcing material such as potassium titanate whisker.

  Various additives can be blended in the resin composition as necessary. For example, high heat conductive fillers such as alumina, magnesia, aluminum nitride, silicon carbide, beryllia, graphite to improve heat dissipation, calcium carbonate, clay, talc, silica, wollastonite to improve wear resistance In order to prevent deterioration due to heat at the time of molding and use, an iodide heat stabilizer or an amine antioxidant can be blended.

  The molding conditions are not limited, and can follow normal resin pulley molding conditions. The resin temperature is 260 to 300 ° C, the mold temperature is 60 to 120 ° C, the filling time is 0.5 to 2.0 seconds, and the pressure is 50 to 200 MPa. Can be about.

  Assuming a resin pulley with a central annular part thickness of 1.4 mm and a circumferential width of ribs of 2.0 mm, a rolling bearing is used as a core, and polyamide 12 is blended with a glass fiber having a cross-sectional shape. The resin composition was injection molded.

  When the obtained resin pulley was cut as shown in FIG. 4 and the cross section of the inner cylinder part between the gates was observed, the ratio of the glass fibers oriented in the circumferential direction was about 30% of the whole glass fibers. It was.

DESCRIPTION OF SYMBOLS 10 Rolling bearing 11 Outer ring 12 Inner ring 13 Ball 14 Cage 20 Resin pulley 21 Inner cylinder part 22 Outer cylinder part 23 Central annular part 24 Rib 35, 35A, 35B Fibrous reinforcement 40 Gate 50 Column part 60 Through-hole

Claims (2)

An inner cylinder portion that is made of a resin composition obtained by blending a fibrous reinforcing material into the resin and that is in contact with the outer peripheral surface of the outer ring of the bearing; and an outer cylinder portion that is arranged concentrically with the inner cylinder portion and over which the belt is stretched; A bearing having a plate-shaped central annular portion that connects between the inner cylindrical portion and the outer cylindrical portion, and ribs that are arranged radially on the central annular portion and connect the inner cylindrical portion and the outer cylindrical portion. In the manufacturing method of the resin pulley molded integrally with
There are locations corresponding to the inner cylindrical portion corresponding to the inner cylindrical portion of the resin pulley, locations corresponding to the outer cylindrical portion corresponding to the outer cylindrical portion, locations corresponding to the rib corresponding to the ribs, and locations corresponding to the central annular portion corresponding to the central annular portion. And having a cavity whose circumferential width is larger than the interval between the central ring portions, the central circle between all adjacent rib portions corresponding to the central ring portion of the cavity. A column part having a boundary between the ring-corresponding portion and the inner tube portion-corresponding portion as a part of the outer periphery is formed so as to penetrate the central annular portion phase portion in the thickness direction. A method for producing a resin pulley , characterized in that a resin composition is injection-molded using a formed mold and a bearing as a core . Gates, of the inner cylindrical portion corresponding portions, method for producing a resin pulley according to claim 1, wherein that you have provided at least 8 equally positioned the inner cylinder portion corresponding portions.

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