JP5556365B2 - Resin pulley injection molding apparatus and injection molding method - Google Patents

Description

  The present invention relates to a resin pulley injection molding apparatus and an injection molding method.

  2. Description of the Related Art An auxiliary drive mechanism for an automobile or the like uses a resin pulley 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. This type of resin pulley includes 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 a rolling element disposed between the outer ring raceway groove and the inner ring raceway groove, A rolling bearing having a cage that rotatably holds the rolling element, and a resin member that is injection-molded on an outer ring of the rolling bearing.

  The resin member is radially disposed on both the flat surface of the large-diameter ring portion, the small-diameter ring portion, the disk portion disposed between the large-diameter ring portion and the small-diameter ring portion, and the disk portion. And a plurality of rib portions connecting the large-diameter ring portion and the small-diameter ring portion.

  Here, in order to mold the resin member on the outer ring, an injection molding method by insert molding is generally performed. Specifically, injection molding is performed by placing a bearing in a cavity of an injection molding apparatus and then filling the cavity with a molten resin via a resin-filled flow path.

  As shown in the conventional resin-filled flow path 100 of FIG. 5, the resin-filled flow path 100 is connected to the spool 102 to which the molten resin is supplied, and to the lower end portion of the spool 102 and is supplied to the spool 102. And a runner 103 that fills the cavity. The spool 102 is formed in a substantially rod shape extending in the vertical direction in the drawing. The runner 103 is a disc-shaped first runner portion 104 connected substantially concentrically with the spool 102, and a plurality of rod-like shapes that are arranged at substantially equal intervals in the circumferential direction on the peripheral portion of the first runner portion 104 and extend downward. Second runner portion 105. Therefore, the molten resin is filled into the cavity via the spool 102, the first runner part 104, and the second runner part 105.

  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. At this time, an excess resin member (hereinafter also referred to as “abandoned resin member”) filled in the resin filling flow path is located at the gate position. Separated and removed to become the final product.

  In addition, in performing this injection molding, the molten resin is gradually cooled at the stage where the molten resin is filled into the cavity via the spool and the runner, and is partially solidified in the resin filling flow path. There is a possibility that the molten resin will not be evenly filled, and as a result, the performance of the resin pulley may be reduced.

  The performance of the resin pulley is, for example, a stable shape such as a belt guide for automobile parts or the like, and has a high roundness or no protrusion formed during injection molding, and a molten resin Is mainly determined based on the fact that the material is uniformly filled and the material is uniform.

  For this reason, in order to improve the performance of the resin pulley, by devising the efficiency of the resin filling flow path, the molten resin filled in the cavity is uniformly cooled, and local shrinkage of the molten resin is suppressed. Is known (for example, see Patent Document 1).

  In addition, an annular film gate is disposed in the vicinity of the periphery of the outer ring of the bearing, and the molten resin is filled into the cavity through the film gate, so that stable supply of the molten resin and material uniformity of the resin member are achieved. Those are known (for example, see Patent Document 2).

Japanese Utility Model Publication No. 02-025962 JP 08-142112 A

  However, in Patent Document 1, since the gate positions are not arranged at equal intervals in the circumferential direction of the cavity, the roundness of the resin member may be deteriorated. Moreover, in the said patent document 2, since the effort which scrapes off a film gate with respect to the resin member shape | molded by the bearing outer ring | wheel increases, it was not optimal in terms of production efficiency. That is, there is still room for improvement with respect to the above-mentioned Patent Document 1 and Patent Document 2 in that the uniform supply of the molten resin into the cavity is efficiently performed with a simple configuration.

  In addition, in this type of injection molding process, as with other injection molding processes, spools and runners that do not become products are filled in the resin-filled flow path in order to increase production costs and respond to the environment in the factory. There is also a strong demand to reduce the amount of discarded resin member, which is a part. Here, in the said patent document 1, it is set as the structure where there are few gate points arrange | positioned in the circumferential direction compared with the past, and it is trying to reduce the quantity of discarded resin members. Moreover, in the said patent document 2, it is thought that the reduction | decrease of a discarded resin member is aimed at as a result similarly to the said patent document 1 by presence of a film gate.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to efficiently fill the cavity with molten resin while improving the molding stability of the resin member with a simple configuration. An injection molding apparatus and molding method for a resin pulley that can reduce the amount of a discarded resin member that is a non-product spool and a runner portion filled in a resin-filled flow path and can increase production efficiency. It is to provide.

The above object of the present invention can be achieved by the following constitution.
(1) In a resin pulley injection molding apparatus for injection molding an annular resin member with respect to an outer ring of a bearing, a bearing is disposed inside at the time of injection molding, and a cavity is formed following the shape of the resin member. A resin-filled flow path that fills the cavity with a molten resin, and the resin-filled flow path is connected to the spool, and the runner is connected to the spool and fills the cavity with the molten resin supplied to the spool. The runner is connected to the midway position of the spool so that a resin pool space is provided at the end of the spool, and the runner is circumferentially connected to the ring portion connected to the spool and the peripheral portion of the ring portion. A plurality of first runner portions, and a plurality of first runner portions having a plurality of convex portions formed at substantially equal intervals, and a curved portion that smoothly connects between connection end portions on the ring portion side of the plurality of convex portions. Convex part of Are connected to an end portion, an injection molding apparatus of the resin pulley, characterized in that it comprises a second runner section rod of filling the molten resin into the cavity, the.
(2) In a resin pulley injection molding apparatus for injection molding an annular resin member with respect to the outer ring of the bearing, the bearing is arranged inside at the time of injection molding, and a cavity formed following the shape of the resin member A resin-filled flow path that fills the cavity with a molten resin, and the resin-filled flow path is connected to the spool, and the runner is connected to the spool and fills the cavity with the molten resin supplied to the spool. The runner is connected to a midway position of the spool so that a resin pool space is provided at the end of the spool, and the runner is concentrically formed with the inner ring connected to the spool and the inner ring. Between the outer ring part to be formed, the inner ring part and the outer ring part, a plurality of rib parts formed at substantially equal intervals in the circumferential direction, and the connection end part on the inner ring part side of the plurality of rib parts Smooth contact A first runner portion having a curved portion, and a plurality of rod-shaped second runner portions connected to the outer ring portion of the first runner portion and filling the cavity with a molten resin. Resin pulley injection molding equipment.
( 3 ) When there are an even number of second runner parts, the plurality of rib parts of the first runner part are connected to intermediate positions between adjacent second runner parts of the outer ring part of the first runner part. ( 2 ) The resin pulley injection molding apparatus according to ( 2 ).
( 4 ) A resin pulley characterized in that an annular resin member is injection-molded with respect to the outer ring of the bearing by the resin pulley injection molding device according to any one of (1) to ( 3 ). Injection molding method.

  According to the resin pulley injection molding apparatus of the present invention, since the runner is connected to the midway position of the spool so that the resin pool space is provided at the end of the spool, it is efficiently melted while having a simple configuration. Resin can be supplied into the cavity, and the molding stability of the resin member can be improved.

  According to the resin pulley injection molding apparatus of the present invention, the runner includes a ring portion connected to the spool, a plurality of convex portions formed at substantially equal intervals in the circumferential direction on the peripheral portion of the ring portion, and The first runner portion having a curved portion that smoothly connects between the connection end portions on the ring side of the plurality of convex portions, and connected to the tip portions of the plurality of convex portions of the first runner portion, and melted into the cavity Since the rod-shaped second runner portion filled with the resin is provided, the volume of the runner can be reduced as compared with the conventional case. As a result, it is possible to reduce the amount of the discarded resin member that is the spool and the runner part that does not become a product and is filled in the resin filling flow path, so that the production efficiency can be increased, and thus the manufacturing cost can be reduced. it can. Further, since the number of gate points is not reduced as compared with the conventional case, the roundness of the resin member is not impaired when the discarded resin member is separated from the resin member in the post-injection molding process. Furthermore, since the molten resin can flow smoothly from the first runner portion to the second runner portion due to the presence of the curved portion, the molten resin can flow uniformly to each gate.

  Further, according to the resin pulley injection molding apparatus of the present invention, the runner includes an inner ring connected to the spool, an outer ring formed concentrically with the inner ring, an inner ring and an outer ring. A first runner having a plurality of rib portions formed at substantially equal intervals in the circumferential direction and a curved portion that smoothly connects between connection end portions on the inner ring side of the plurality of rib portions. And a plurality of rod-shaped second runner portions connected to the outer ring portion of the first runner portion and filling the cavity with molten resin, the volume of the runner can be reduced as compared with the conventional case. it can. As a result, it is possible to reduce the amount of the discarded resin member that is the spool and the runner part that does not become a product and is filled in the resin filling flow path, so that the production efficiency can be increased, and thus the manufacturing cost can be reduced. it can. Further, since the number of gate points is not reduced as compared with the conventional case, the roundness of the resin member is not impaired when the discarded resin member is separated from the resin member in the post-injection molding process. Furthermore, since the molten resin can flow smoothly from the first runner portion to the second runner portion due to the presence of the curved portion, the molten resin can flow uniformly to each gate.

  Further, according to the resin pulley injection molding apparatus of the present invention, when the second runner portion is an even number, the plurality of rib portions of the first runner portion are adjacent to the outer ring portion of the first runner portion. Since it is connected to an intermediate position between the second runner parts, the volume of the runner can be further reduced. Thereby, since the amount of the discarded resin member can be further reduced, the manufacturing cost can be further reduced.

It is sectional drawing explaining the resin pulley manufactured with the injection molding apparatus of the resin pulley which concerns on this invention. It is principal part sectional drawing explaining 1st Embodiment of the injection molding apparatus of the resin pulley which concerns on this invention. It is a schematic diagram explaining the resin filling flow path of the injection molding apparatus of the resin pulley shown in FIG. It is a schematic diagram explaining the resin filling flow path of 2nd Embodiment of the injection molding apparatus of the resin pulley which concerns on this invention. It is a schematic diagram explaining the resin filling flow path of the injection molding apparatus of the conventional resin pulley.

  Hereinafter, embodiments of an injection molding apparatus for resin pulleys according to the present invention will be described in detail based on the drawings. 3 and 4 are perspective views showing the resin-filled flow channel filled with the molten resin for easy understanding of the resin-filled flow channel of each embodiment, and these are discarded resin members. And finally discarded or recycled in the manufacturing process.

  First, with reference to FIG. 1, the resin pulley manufactured by the resin pulley injection molding apparatus according to the present invention will be described.

  As shown in FIG. 1, the resin pulley 10 includes an outer ring 12 having an outer ring raceway groove 12a on the inner peripheral surface, an inner ring 13 having an inner ring raceway groove 13a on the outer peripheral surface, an outer ring raceway groove 12a and an inner ring raceway groove 13a. A rolling bearing 11 having a plurality of balls (rolling elements) 14 that are arranged so as to be able to roll between them, and a cage 15 that holds the plurality of balls 14 at substantially equal intervals in the circumferential direction; And a resin member 20 fixed to the outer peripheral surface.

  The resin member 20 includes a large-diameter ring portion 21, a small-diameter ring portion 22, a disk portion 23 disposed between the large-diameter ring portion 21 and the small-diameter ring portion 22, and both planes of the disk portion 23. A plurality of rib portions 24 are arranged on the upper surface and connect the large-diameter ring portion 21 and the small-diameter ring portion 22. In the present embodiment, the plurality of ribs 24 are provided on both planes of the disc portion 23, but are not limited thereto, and are provided only on one plane of the disc portion 23. Also good.

(First embodiment)
Next, with reference to FIG.2 and FIG.3, 1st Embodiment of the injection molding apparatus of the resin pulley which concerns on this invention is described.

  As shown in FIG. 2, the injection molding device 30 for the resin pulley 10 of the present embodiment includes a mold 40 in which the rolling bearing 11 is set, and a molten resin (not shown) that supplies the molten resin to the mold 40. A supply device.

  The mold 40 includes an upper mold 41, an intermediate mold 42, and a lower mold 43. The rolling bearing 11 is disposed between the middle mold 42 and the lower mold 43, and the outer ring 12. A cavity 50 for molding the resin member 20 is formed on the outer peripheral surface of the substrate. The cavity 50 is formed following the shape of the resin member 20. Further, a holding boss 43 a that is fitted into the inner ring 13 of the rolling bearing 11 and holds the rolling bearing 11 is formed at the center of the lower mold 43.

  As shown in FIG. 2, the upper mold 41 and the middle mold 42 are formed with a resin filling channel 60 for supplying a molten resin to the cavity 50. The resin filling channel 60 is formed as shown in FIG. As shown in FIG. 2, the spool 62 and the runner 63 are provided. The spool 62 is connected to a molten resin supply device (not shown) and first guides the molten resin and supplies the molten resin to the runner 63.

  As shown in FIGS. 2 and 3, the runner 63 is connected at an intermediate position of the spool 62 so that the molten resin is guided radially from the spool 62 and a resin pool space 64 is provided at the lower end of the spool 62. The

  The runner 63 includes a first runner portion 65 connected to the spool 62 and a second runner portion 66 connected to the first runner portion 65. In addition, according to the runner 63 of this embodiment, compared with the runner 103 of the said conventional resin filling flow path 100, the mass of a discarded resin member can be reduced about 54%.

  The first runner portion 65 includes a ring portion 67 connected to the spool 62, a plurality (16 in the present embodiment) of convex portions 68 formed on the peripheral portion of the ring portion 67 at substantially equal intervals in the circumferential direction, And a curved portion 69 that smoothly connects the connection end portions of the plurality of convex portions 68 on the ring portion 67 side.

  The second runner portion 66 is formed in a rod shape so as to follow the vertical direction of the mold 40, and its upper end portion is connected to the tip portions of the plurality of convex portions 68 of the first runner portion 65, and its lower end portion is Each is connected to the cavity 50 via the gate 61.

  In order to mold the resin member 20 using the injection molding apparatus 30 configured in this way, first, the rolling bearing 11 is fitted and arranged on the holding boss 43 a of the lower mold 43, and then on the lower mold 43. The middle mold 42 and the upper mold 41 are placed, and the mold 40 is closed. Then, the molten resin is supplied from the molten resin supply device (not shown) to the resin filling channel 60, whereby the cavity 50 is filled with the molten resin through the spool 62 and the runner 63 of the resin filling channel 60.

  At this time, since the resin reservoir space 64 is provided where the molten resin flows from the spool 62 to the runner 63, the molten resin supplied to the spool 62 is in the resin reservoir space 64 before spreading to the runner 63. Filled. A part of the molten resin filled in the resin reservoir space 64 is solidified by cooling, and the molten resin is sequentially applied to the solidified resin, so that the molten resin smoothly flows from the spool 62 to the runner 63. The cavities 50 are filled uniformly over the entire circumference.

  As described above, according to the injection molding apparatus 30 of the present embodiment, the runner 63 is connected at an intermediate position of the spool 62 so that the resin reservoir space 64 is provided at the lower end portion of the spool 62. Although it is a structure, molten resin can be efficiently supplied in the cavity 50, and the molding stability of the resin member 20 can be improved.

  Further, according to the injection molding apparatus 30 of the present embodiment, the runner 63 includes the ring portion 67 connected to the spool 62 and a plurality of convex portions formed at substantially equal intervals in the circumferential direction on the peripheral portion of the ring portion 67. 68, a first runner portion 65 having a curved portion 69 that smoothly connects the connecting end portions on the ring portion 67 side of the plurality of convex portions 68, and tips of the plurality of convex portions 68 of the first runner portion 65. Since the rod-shaped second runner portion 66 is connected to each portion and the cavity 50 is filled with the molten resin, the volume of the runner 63 can be reduced as compared with the conventional case. As a result, it is possible to reduce the amount of the discarded resin member that is the portion of the spool 62 and the runner 63 that is not filled with the product, which is filled in the resin-filled flow path 60, so that the production efficiency can be increased and thus the manufacturing cost can be reduced. can do. Further, since the number of gate points is not reduced as compared with the conventional case, the roundness of the resin member 20 is not impaired when the discarded resin member is separated from the resin member 20 in the post-injection molding process. Further, the presence of the curved portion 69 allows the molten resin to flow smoothly from the first runner portion 65 to the second runner portion 66, so that the molten resin can flow uniformly to each gate 61. In addition, by making the plurality of convex portions 68 have a substantially trapezoidal cross section, the first runner portion 65 is caught by the upper mold 41 and each gate 61 is separated from the upper mold 41, so that the processing of the runner is easy. is there.

(Second Embodiment)
Next, a second embodiment of the resin pulley injection molding apparatus according to the present invention will be described with reference to FIG. Note that portions that are the same as or equivalent to those of the first embodiment are denoted by the same or equivalent reference numerals in the drawings, and description thereof is omitted or simplified.

  As shown in FIG. 4, the resin-filled flow path 70 of the present embodiment has a spool 62 and a runner 73. The runner 73 is connected at an intermediate position of the spool 62 so that the molten resin is guided radially from the spool 62 and a resin pool space 64 is provided at the lower end of the spool 62.

  The runner 73 includes a first runner portion 75 connected to the spool 62 and a second runner portion 76 connected to the first runner portion 75. In addition, according to the runner 73 of this embodiment, compared with the runner 103 of the said conventional resin filling flow path 100, the mass of a discarded resin member can be reduced about 56%.

  The first runner portion 75 includes an inner ring portion 77 connected to the spool 62, an outer ring portion 78 formed concentrically with the inner ring portion 77, and the inner ring portion 77 and the outer ring portion 78 in the radial direction. A curve that connects and smoothly connects a plurality (eight in this embodiment) of ribs 79 formed at substantially equal intervals in the circumferential direction and a connecting end of the plurality of ribs 79 on the inner ring part 77 side. Part 80.

  A plurality of second runner portions 76 are formed in a rod shape (16 in the present embodiment) along the vertical direction of the mold 40, and the upper end portions thereof are respectively connected to the outer ring portions 78 of the first runner portion 75. The lower ends thereof are connected to the cavities 50 through the gates 61, respectively.

  In the present embodiment, the 16 second runner portions 76 are arranged on the lower surface of the outer ring portion 78 at substantially equal intervals in the circumferential direction, and the eight rib portions 79 of the first runner portion 75 are the first The outer ring portion 78 of the runner portion 75 is connected to every other intermediate position between the adjacent second runner portions 76 and 76.

  As described above, according to the injection molding apparatus 30 of the present embodiment, the runner 73 includes the inner ring portion 77 connected to the spool 62 and the outer ring portion 78 formed concentrically with the inner ring portion 77. The inner ring portion 77 and the outer ring portion 78 are connected to each other, and a plurality of rib portions 79 formed at substantially equal intervals in the circumferential direction and a connection end portion on the inner ring portion 77 side of the plurality of rib portions 79 are smoothly smoothed. A first runner portion 75 having a curved portion 80 connected to the plurality of rod-shaped second runner portions 76 connected to the outer ring portion 78 of the first runner portion 75 and filling the cavity 50 with molten resin; Therefore, the volume of the runner 73 can be reduced as compared with the conventional case. As a result, it is possible to reduce the amount of the discarded resin member that is the portion of the spool 62 and the runner 73 that is not filled with the product, which is filled in the resin filling flow path 70, so that the production efficiency can be increased, and thus the manufacturing cost can be reduced. can do. Further, since the number of gate points is not reduced as compared with the conventional case, the roundness of the resin member 20 is not impaired when the discarded resin member is separated from the resin member 20 in the post-injection molding process. Further, the presence of the curved portion 80 allows the molten resin to flow smoothly from the first runner portion 75 to the second runner portion 76, so that the molten resin can flow uniformly to each gate 61.

Further, according to the injection molding device 30 of the present embodiment, the eight rib portions 79 of the first runner portion 75 are between the adjacent second runner portions 76 and 76 of the outer ring portion 78 of the first runner portion 75. Therefore, the volume of the runner 73 can be further reduced. Thereby, since the amount of the discarded resin member can be further reduced, the manufacturing cost can be further reduced.
Other configurations and operational effects are the same as those in the first embodiment.

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

DESCRIPTION OF SYMBOLS 10 Resin pulley 11 Rolling bearing 12 Outer ring 20 Resin member 30 Injection molding apparatus 40 Mold 41 Upper mold 42 Middle mold 43 Lower mold 50 Cavity 60 Resin filling flow path 61 Gate 62 Spool 64 Resin pool space 63 Runner 65 First 1 runner part 66 2nd runner part 67 ring part 68 convex part 69 curved part 70 resin filling flow path 73 runner 75 first runner part 76 second runner part 77 inner ring part 78 outer ring part 79 rib part 80 curved part

Claims (4)

In an injection molding apparatus of a resin pulley for injection molding an annular resin member with respect to an outer ring of a bearing,
A cavity formed inside the resin member in accordance with the shape of the resin member, and the bearing is disposed inside during injection molding;
A resin-filled flow path for filling the cavity with a molten resin,
The resin-filled flow path is
A spool to which the molten resin is supplied;
A runner connected to the spool and filling the cavity with the molten resin supplied to the spool;
The runner is connected to an intermediate position of the spool so that a resin pool space is provided at an end of the spool ,
The runner
Smoothly between the ring portion connected to the spool, the plurality of convex portions formed at substantially equal intervals in the circumferential direction on the peripheral portion of the ring portion, and the connection end portion on the ring portion side of the plurality of convex portions A first runner portion having a curved portion connected to
An injection molding of a resin pulley , comprising: a rod-shaped second runner portion connected to tip ends of the plurality of convex portions of the first runner portion, and filling the cavity with the molten resin. apparatus. In an injection molding apparatus of a resin pulley for injection molding an annular resin member with respect to an outer ring of a bearing,
A cavity formed inside the resin member in accordance with the shape of the resin member, and the bearing is disposed inside during injection molding;
A resin-filled flow path for filling the cavity with a molten resin,
The resin-filled flow path is
A spool to which the molten resin is supplied;
A runner connected to the spool and filling the cavity with the molten resin supplied to the spool;
The runner is connected to an intermediate position of the spool so that a resin pool space is provided at an end of the spool,
The runner
The inner ring part connected to the spool, the outer ring part formed concentrically with the inner ring part, the inner ring part and the outer ring part are connected, and formed at substantially equal intervals in the circumferential direction. A first runner portion having a plurality of rib portions, and a curved portion that smoothly connects between the connection end portions on the inner ring portion side of the plurality of rib portions,
A resin pulley injection molding apparatus comprising: a plurality of rod-shaped second runner portions connected to the outer ring portion of the first runner portion and filling the cavity with the molten resin. When the second runner part is an even number,
Wherein the plurality of ribs of the first runner section according to claim 2, characterized in that the said outer ring portion of the first runner section, is connected to an intermediate position between the adjacent second runner section Resin pulley injection molding equipment. An injection molding method for a resin pulley, wherein an annular resin member is injection-molded with respect to an outer ring of a bearing by the resin-pulley injection molding device according to any one of claims 1 to 3 .

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