JP5625817B2 - Resin pulley - Google Patents

Description

  The present invention relates to a resin pulley, for example, a resin pulley used as an idler pulley or an auto tensioner pulley for applying a desired tension to an endless belt or timing belt for driving an auxiliary machine around an automobile engine. is there.

  2. Description of the Related Art Conventionally, resin pulleys in which a resin member is injection-molded on an outer ring of a bearing, such as an idler pulley or an auto tensioner pulley, have been used in an accessory drive mechanism such as an automobile. This type of resin pulley includes a rolling bearing having an outer ring having an outer ring raceway groove on an inner peripheral surface, an inner ring having an inner ring raceway groove on an outer peripheral surface, and rolling elements disposed between the both raceway grooves. The resin member is formed on the outer ring outer peripheral portion of the rolling bearing. The resin member includes an outer diameter side cylindrical portion, an inner diameter side cylindrical portion, a disk portion disposed between the outer diameter side cylindrical portion and the inner diameter side cylindrical portion, and radial surfaces on both planes of the disk portion. And a plurality of ribs for connecting the outer diameter side cylindrical portion and the inner diameter side cylindrical portion.

  In order to mold a resin member on the outer ring of a rolling bearing, an injection molding method by insert molding is generally performed. Specifically, injection molding is performed by placing a bearing in a molding die of an injection molding apparatus and then injecting and filling molten resin into the cavity through a gate. And the above-mentioned resin member is shape | molded by the outer ring | wheel of a bearing by cooling the molten resin with which this cavity was filled. Next, the mold is opened, and the resin pulley is taken out to become a product.

In the case of a resin pulley obtained by injection molding of the resin member as described above, weight reduction and cost reduction can be achieved compared to a press pulley that is manufactured by pressing a metal plate that has been widely used conventionally. be able to. On the other hand, deformation due to variations in the cooling rate in the cavity during injection molding or unevenness due to a portion where the molten resin has joined and fused (hereinafter referred to as a weld portion) occurs, making it difficult to ensure the accuracy of the shape of the resin pulley. . More specifically, since the roundness of the outer peripheral surface of the resin pulley deteriorates, the outer peripheral surface of the resin pulley and the peripheral surface of the belt collide (hit each other) as the belt travels. A meshing sound with a relatively high frequency may occur.
As for the performance of resin pulleys, for example, for applications such as belt guides for automobile parts, etc., the roundness is good or the shape is stable such that there are no protrusions formed during injection molding, and melting It is mainly required that the resin is uniformly filled and the material (strength) is uniform.

  As a prior art for improving the roundness of a resin pulley, in Patent Document 1, the thickness of the annular plate portion is made larger than the rib thickness, so that the flow of the resin flowing through the annular plate portion during the injection molding is reduced to the rib portion. In other words, it is disclosed that the unevenness caused by the weld portion of the outer diameter cylindrical portion is kept small by flowing earlier. On the other hand, in Patent Document 2, by setting the pulley inner cylindrical portion thickness to be larger than the disc portion thickness, the resin is filled in the inner cylindrical portion prior to injection molding, and then passed through the rib portion and the disc portion. A molding method in which a resin flows into the outer cylindrical portion is disclosed.

JP 2008-290402 A JP 2002-266990 A

  However, the resin pulley described in Patent Document 1 has a problem that when the number of gates is reduced for cost reduction, the flow of the molten resin becomes non-uniform and the roundness deteriorates. In addition, when the injection pressure is increased to improve the roundness of the outer peripheral surface of the pulley, a gate for injecting molten resin is provided in the vicinity of the outer ring of the rolling bearing. Since the roundness collapses, there is a problem that the rotational accuracy and life of the rolling bearing deteriorate.

The present invention is a resin in which the molten resin is efficiently filled into the cavity while improving the roundness of the outer peripheral surface of the pulley by efficiently filling the cavity with the molten resin while having a reduced number of gates. Aim to provide a pulley made of

In order to solve the above problems, the resin pulley of the present invention is provided between an inner diameter side cylindrical portion and an outer diameter side cylindrical portion provided concentrically with each other, and between the inner diameter side cylindrical portion and the outer diameter side cylindrical portion. And a plurality of ribs provided radially at equal intervals on both side surfaces of the disk portion, and the inner diameter side cylindrical portion is disposed around the outer ring constituting the radial rolling bearing. In a resin pulley fixed in a state where a portion near the outer periphery is molded on the inner periphery side, the disc portion is formed in an annular shape concentric with the inner diameter side cylindrical portion and the outer diameter side cylindrical portion. A plurality of gates for feeding molten resin at the time of injection molding are arranged at equal intervals in the circumferential direction on one end side in the axial direction of the annular thick part. width a _a, the radial width of the annular thick portion a _R, the axial width of the circular plate portion B _a, the circumferential direction of the rib When the width R _C, diameter of Gate was G _D, characterized by satisfying the following equation.
A _A > B _A
A _A > R _C
A _R > G _D
In the resin pulley of the present invention, the axial thickness of the annular thick portion is made larger than the axial width of the plate portion and the circumferential width of the rib, so that the molten resin injected from the gate is annular thick portion. After that, the rib part, the outer diameter side cylindrical part of the pulley, and the inner diameter side cylindrical part are filled, so even if the number of gate points is small, the trueness is about the same as in the case of all-point gates where gates are provided between ribs. Circularity can be obtained.

Furthermore, the resin pulley of the present invention has an even number of ribs between the gates, has an intermediate thick portion in the middle from each gate of the annular thick portion, and the axial width of the intermediate thick portion. the C _a, when the radial width of the intermediate thick portion was set to C _R, and satisfies the following formula.
C _A > A _A
C _R > A _R
By making the middle part of each gate thicker than the annular thick part, it is possible to prevent the strength of the resin pulley from being lowered by the weld part.

  According to the present invention, in a resin pulley in which a resin member is injection-molded on an outer ring of a rolling bearing, an annular thick part having gates installed at equal intervals in the circumferential direction is made thicker than a disk part and a rib. By the configuration, the molten resin injected from the gate is filled from the annular thick part, and then flows in the disk part and the rib, and is filled in the pulley outer diameter side cylindrical part and inner diameter side cylindrical part, Even if the number of gates is small, the same resin flow as that of all-point gates can be reproduced in a pseudo manner, so that the same degree of roundness of the pulley outer circumference as that of all-point gates can be obtained and the cost can be reduced. There is an effect. In addition, since non-uniform pressure is not exerted on the bearing outer ring, the collapse of the roundness of the bearing outer ring can be minimized.

It is a side view explaining embodiment of the resin pulley concerning this invention. It is II sectional drawing of FIG. It is a side view explaining the modification of embodiment of the resin pulleys concerning this invention. It is II-II sectional drawing of FIG.

Hereinafter, embodiments of a resin pulley according to the present invention will be described in detail with reference to the drawings.
(Embodiment)
First, an embodiment of a resin pulley according to the present invention will be described with reference to FIGS. 1 and 2. The resin pulley 1 is integrally formed in a state where the outer peripheral portion of the outer ring 4 of the rolling bearing 2 is wrapped with a resin member 9. In the rolling bearing 2, an inner ring 3 and an outer ring 4 are relatively rotated via rolling elements 5 and 5 held by a cage 6.
The resin member 9 includes an outer diameter side cylindrical portion 11 and an inner diameter side cylindrical portion 10 that are concentric with the rolling bearing 2, and a disk portion 12 that is disposed between the outer diameter side cylindrical portion 11 and the inner diameter side cylindrical portion 10. And a plurality of ribs 13 arranged radially on both planes of the disk portion 12 at equal intervals and connecting the outer diameter side cylindrical portion 11 and the inner diameter side cylindrical portion 10. In the present embodiment, the plurality of ribs 13 are provided on both planes of the disc portion 12, but are not limited to this, and are provided only on one plane of the disc portion 12. Also good.

Further, the disc portion 12 has an annular thick portion 14 having an axial width larger than that of the disc portion 12 at an intermediate portion between the outer diameter side cylindrical portion 11 and the inner diameter side cylindrical portion 10. On one end side in the axial direction of the annular thick portion 14, a gate 15 is provided for injecting molten resin into the intermediate position of each rib 13 at equal intervals in the circumferential direction. Further, the annular thick portion 14 has an annular shape concentric with the outer diameter side cylindrical portion 11 and the inner diameter side cylindrical portion 10, and the axial width A _A of the annular thick portion 14 is the disc portion 12. greater than the circumferential width R _C of the axial width B _a and the ribs 13 of radial width a _R annular thick portion 14 is made larger than the diameter G _D of the gate 15.

Next, the manufacturing method of the resin pulley of the present invention will be described.
The rolling bearing 2 as an insert product is loaded into a molding die, and molten resin from an injection device (not shown) is injected into the cavity from each gate 15. The injected molten resin flows into the annular thick part 14 in the circumferential direction, and the annular thick part 14 is filled with the molten resin in advance. This is because the axial width A _A of the annular thick portion 14 is formed relatively larger than the axial width B _A of the disc portion 12 and the circumferential width _{RC of the} rib 13. The reason is to try to advance in the annular thick portion 14 having a small thickness. However, a part of the molten resin flows into the disc portion 12 or the rib 13. When the annular thick portion 14 is completely filled with the molten resin, the molten resin flowing into the disc portion 12 and the rim 13 flows and fills the outer diameter side cylindrical portion 11 and the inner diameter side cylindrical portion 10. The resin pulley 1 is molded.

As described above, the resin pulley 1 of the present invention has a structure in which the portions where the gates are installed at equal intervals in the circumferential direction are thickened in an annular shape, and the axial width A _A of the annular thick portion 14 is axial width _{B a} of the disc portion 12, the relationship between the circumferential width _{R C} of the ribs 13 _{a a>} B _a, a a a> _{R C,} the radial width of the annular thick portion 14 _{a R} and the gate 15 relationship between the diameter _{G D} of is an _a R> _{G D.}
As a result, the molten resin injected from the gate 15 provided between the ribs is first filled into the annular thick portion 14, and then passes through the disc portion 12 and the rib 13 to be evenly radially outer. Since it flows to the diameter side and the inner diameter side, there is an effect similar to that when the gate 15 is installed between all ribs, and the resin flow similar to that of the all-point gate can be reproduced in a pseudo manner. Unevenness can be kept very small. Further, the cost can be reduced by reducing the number of gates 15. Further, since the gate 15 is provided between the outer diameter side cylindrical portion 11 and the inner diameter side cylindrical portion 10, the outer ring 4 is not subjected to excessive pressure and the pressure is uniform. It does not worsen the circularity.

  In this embodiment, the resin material constituting the resin pulley 1 is polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 46, polyamide 610, polyamide 612, aromatic polyamide having an aromatic ring, non-cyclic ring. Addition of fillers such as reinforced fibers such as glass fibers and minerals such as talc and mica, based on thermoplastic resins such as polyphenylene sulfide (PPS), phenol resin, etc. Composite materials can be used.

  More specifically, glass fiber, carbon fiber, aramid fiber, potassium titanate whisker or the like can be used as the filler, and silica (SiO2) or alumina (Al2O3) particles, calcium carbonate (CaO3) can be used as the particulate filler. , Talc, mica, graphite, etc. can be used. Furthermore, each of the above fillers can be used alone, but when a fibrous filler and a particulate filler are combined, the particulate filler can suppress the volume shrinkage anisotropy of the synthetic resin, The decrease in mechanical strength can be suppressed by the fiber filler.

(Modification)
Next, a modification of the resin pulley according to the present invention will be described with reference to FIGS. Note that the same or equivalent parts as those of the above embodiment are given the same or equivalent reference numerals in the drawings, and the description thereof is omitted or simplified.
The resin pulley 1a of this modification has an intermediate thick portion 16 in the annular thick portion 14. The intermediate thick portion 16 is formed at an intermediate position in the circumferential direction of each gate 15, and an even number of ribs 13 exist between the gates 15.

Since there are an even number of ribs 13 between the gates 15, the ribs 13 do not exist in the intermediate part of the gates 15 where the weld is generated, and the intermediate thick part 16 can be formed. Relationship axial width A _A the axial width C _A an annular thick portion 14 of the intermediate thick portion 16 is C _A> A _A, the radial width of the intermediate thick portion 16 C _R and an annular wall relation radial width _{a R} of the thick portion 14 has a _C R> _{a R.} With the above structure, the molten resin injected from the gate 15 provided between the ribs 13 is filled from the annular thick part 14, and then flows in the disk part 12 and the rib 13 to become the outer diameter side cylinder. Since the resin flow similar to that of the all-point gate can be reproduced even when the number of gate points is small by filling the portion 11 and the inner diameter side cylindrical portion 10, the pulley outer peripheral roundness is similar to that of the all-point gate. Can be obtained and the cost can be reduced. Furthermore, the strength of the resin pulley can be prevented from decreasing by making the weld portion thick.
In addition, about another structure and an effect, it is the same as that of the above-mentioned embodiment.

In addition, this invention is not limited to what was illustrated by embodiment and the modification which were mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, in the above-described embodiment, the ball bearing is described as an example of the bearing. However, the present invention is not limited to this, and the present invention may be applied to any bearing that requires the resin member to be fixed to the outer ring.

  The present invention provides a pulley made of resin, for example, an auxiliary machine for an automobile engine, an endless belt for driving a camshaft, a timing belt, or the like, or a desired belt wrap angle. It can be used as an idler pulley or an auto tensioner pulley used to guide the belt.

DESCRIPTION OF SYMBOLS 1, 1a Resin pulley 2 Rolling bearing 3 Inner ring 4 Outer ring 5 Rolling body 6 Cage 9, 9a Resin member 10 Inner diameter side cylindrical part 11 Outer diameter side cylindrical part 12 Disc part 13 Rib 14 Annular thick part 15 Gate 16 Middle thick part

Claims (1)

An inner diameter side cylindrical portion and an outer diameter side cylindrical portion provided concentrically with each other, a disc portion provided between the inner diameter side cylindrical portion and the outer diameter side cylindrical portion, and both sides of the disc portion, etc. A plurality of ribs provided radially at intervals, and the inner diameter side cylindrical portion is fixed around the outer ring constituting the radial rolling bearing in a state in which a portion near the outer periphery of the outer ring is molded on the inner periphery side. In the pulley made of resin,
The disc portion has an annular thick portion formed concentrically with the inner diameter side cylindrical portion and the outer diameter side cylindrical portion, and a circumferential direction or the like is provided at one end side in the axial direction of the annular thick portion. a plurality of arranged gate, annular wall an axial width a _a thick _portion, the radial width of the annular thick portion a _R, the axial direction of the disk portion for feeding a molten resin during injection molding to the spacing when the width B _a, the rib circumferential width R _C, the diameter of the gate was G _D, meet the following equation,
A _A > B _A
A _A > R _C
A _{R> G D}
There is an even number of ribs between the gates, the annular thick part has an intermediate thick part in the middle from each gate, the axial width of the intermediate thick part is C _A , and the intermediate thick part when the radial width is C _R, resin pulley to satisfy the following equation.
C _A > A _A
C _R > A _R

Images