JP2011161702A - Injection molding mold for resin product with core metal inserted into annular portion, method of manufacturing the resin product, and resin retainer with core metal inserted into annular portion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin retainer with a core metal inserted into an annular portion, which can enhance the reinforcing effect of the core metal by combining the resin firmly with the core metal, ensure required precision and allow a cost reduction. <P>SOLUTION: The annular core metal 21 has two or more radial-direction positioning pins 4 protruding from a template 2 into a cavity C and extending in the axial direction so as to be separated from each other in the circumferential direction, three or more axial-direction positioning pins 5 protruding from the template 2 into the cavity C and extending in the axial direction so as to be separated from one another in the circumferential direction and engagement holes 21a to be engaged with the radial-direction positioning pins 4. The annular core metal 21 is positioned in the radial direction by engaging the radial-direction positioning pins 4 in the engagement holes 21a and in the axial direction by bringing the axial-direction positioning pins 5 into contact with the axial-direction end surface 21B of the core metal 21, at the back of the axial-direction end surface 21A of the core metal 21 receiving the pressure of a molten resin P flowing into the cavity C, and stopping the axial-direction positioning pins 5 there. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin product in which a core metal is inserted into an annular portion, and more specifically, an injection mold for manufacturing the product, a method for manufacturing the product, and a core in the annular portion as the product. The present invention relates to a resin cage in which gold is inserted.

For example, in a machine tool that processes a workpiece into a desired shape and size, the spindle is rotated at a high speed in order to improve machining efficiency, and the spindle rolling bearing is required to have excellent high-speed rotation.
Roller bearing cages used under such high-speed rotation and rapid acceleration / deceleration require high roundness, light weight and high rigidity (dimensional stability against centrifugal force), heat resistance, etc. Therefore, a resin cage using a PEEK (polyether ether ketone) material having such characteristics is often used.

  Also, as a resin retainer that inserts a metal core (annular metal plate) to increase rigidity to prevent deformation based on centrifugal force, a pocket that holds a rolling element in an annular main portion made of synthetic resin The cored bar is attached in a non-separated state to the axial end surface opposite to the axial end surface on which the resin is formed by allowing the resin to penetrate through tapered holes formed at a plurality of locations in the circumferential direction during injection molding. As described above (for example, refer to Patent Document 1), without forming a hole in the cored bar, it is formed on the axial end surface opposite to the axial end surface in which the pocket for holding the rolling element in the annular main portion is formed. In a state in which the cored bar is embedded in the recessed part and integrated (for example, see Patent Document 2), the cored bar is sandwiched and positioned by the holding pins protruding from the fixed side mold plate and the movable side mold plate Injection There such as those molded to wrap the core metal is by performing.

JP-A-8-145041 International Publication No. 07/058351 Pamphlet

In the conventional technology as described above, the PEEK resin retainer molded without using a metal core is suitable for high-speed rolling bearings due to the excellent mechanical properties and heat resistance of the PEEK material. Can be obtained, but the cost is increased because the material is very expensive.
In addition, it is difficult to respond to the demand for further high-speed rotation even if a device such as a mold shape or setting of very strict molding conditions is devised.

Moreover, in the resin cage in which the cored bar is inserted as in Patent Documents 1 and 2, the resin cage can be reinforced by the strength and rigidity of the cored bar, but the resin is not encased in the resin. Since the bonding force between the core metal and the core metal is not strong but relatively weak, the reinforcing effect of the core metal is limited, and it is difficult to meet the demand for further high-speed rotation.
Furthermore, in a resin retainer in which a core metal that is injection-molded in a state where the core metal is sandwiched and held by a holding pin is inserted, the resin and the core metal can be firmly bonded by wrapping the core metal with resin. Because the core pin is sandwiched and positioned by the holding pin, when the holding pin is separated from the core after the resin is solidified, a restoring force of the elastic deformation of the core is generated. Since the bonding force is strong, the resin portion is deformed under the influence of a highly rigid core, and the required accuracy may not be ensured for the resin holder.

  Therefore, in view of the above-mentioned situation, the present invention intends to solve the problem that the reinforcing effect of the core metal can be enhanced by firmly bonding the resin and the core metal without increasing the cost, and the required accuracy can be obtained. An injection mold for a resin product in which a metal core is inserted in an annular part, a method for producing a resin product in which a metal core is inserted in an annular part, and a resin holding in which the metal core is inserted in an annular part can be secured. It is in providing a vessel.

In order to solve the above problem, a resin product injection molding die in which a metal core is inserted into an annular portion according to the present invention protrudes into the cavity from the mold plate and extends in the axial direction while being spaced apart in the circumferential direction. An annular cored bar having at least three radial positioning pins and three or more axial positioning pins extending in the axial direction and spaced apart in the circumferential direction, and having an engagement hole that engages with the radial positioning pins Is positioned in the radial direction by engaging the radial positioning pin with the engagement hole, and the shaft on the back side of the axial end surface of the core metal that receives the pressure of the molten resin flowing into the cavity Positioning in the axial direction is achieved by abutting the axial positioning pin on the direction end face.
According to such a configuration, by performing injection molding of a resin product in which a core metal is inserted into an annular portion using this injection mold, the resin and the core metal are wrapped by wrapping the core metal with the resin. Since it can couple | bond firmly, the reinforcement effect by a metal core can be heightened.

In addition, the radial and axial positioning of the cored bar is such that the radial positioning pin is engaged with the engagement hole of the cored bar, and the axial direction of the cored bar that receives the pressure of the molten resin flowing into the cavity Since this is done by abutting the axial positioning pin against the axial end surface on the back side of the end surface, the metal core is sandwiched by the holding pins protruding from the fixed side mold plate and the movable side mold plate as in the prior art. It is not in the state restrained by.
Therefore, even if the radial positioning pin and the axial positioning pin are separated from the core after the resin is solidified, the restoring force of the elastic deformation of the core does not occur. There is no need to decline under the influence of
In addition, since the reinforcement effect of the metal core and the accuracy can be improved, it is not necessary to use expensive resin materials having excellent mechanical properties such as PEEK materials, thereby reducing the cost. Can do.

According to the present invention, a resin product manufacturing method in which a metal core is inserted into an annular portion is melted in a state where the metal core is accommodated in the cavity using the injection mold in order to solve the problem. A product is molded by filling the resin into the cavity.
Therefore, according to the method for producing a resin product in which a core metal is inserted into the annular portion according to the present invention, the injection molding of the resin product in which the core metal is inserted into the annular portion performed using the above-described injection molding die There are similar features.

In order to solve the above problems, a resin cage in which a cored bar is inserted into an annular portion according to the present invention is a comb type cage or a crown type cage produced by the method for producing a resin product, and a pocket is formed. The radial positioning pin and the punch hole for the axial positioning pin are formed on the axial end surface on the back side of the axial end surface.
Further, a tapered roller bearing retainer having a shape in which a large-diameter annular portion and a small-diameter annular portion manufactured by the resin product manufacturing method are connected by a column portion, the large-diameter annular portion and the small-diameter An annular cored bar is inserted into each of the annular parts, and the radial positioning is performed on both the large-diameter annular part and the small-diameter annular part on the same axial end surface of both axial end faces. A punch hole for the pin and the axial positioning pin is formed.
According to such a configuration, for a roller bearing comb cage, a ball bearing crown cage, and a tapered roller bearing having a shape in which a large-diameter annular portion and a small-diameter annular portion are connected by a column portion. In cages, it is possible to meet the demand for higher speed rotation of rolling bearings by improving strength, rigidity, and accuracy, and it is possible to reduce costs while improving such characteristics. Can be greatly improved.

  As described above, according to the injection mold of the resin product in which the core metal is inserted into the annular portion according to the present invention, the manufacturing method of the product, and the resin retainer in which the core metal is inserted into the annular portion, the core The resin product (resin retainer) with gold inserted wraps the core metal with resin so that the resin and the core metal are firmly bonded. Therefore, the reinforcing effect of the core metal is high, and the strength and rigidity can be improved. This is possible, and injection molding is not performed in a state where the core metal is constrained, so the accuracy of the resin product does not deteriorate due to the influence of the highly rigid core metal, and it is necessary to use an expensive resin material such as PEEK material. There is no. Therefore, since a general-purpose engineering plastic material such as a polyamide resin can be used, the range of selection of the resin material is widened, so that a remarkable effect that the cost can be reduced is achieved.

It is a longitudinal cross-sectional view of the injection mold concerning Embodiment 1 of this invention. It is a figure which shows the example of the resin product which inserted the metal core in the annular part which concerns on Embodiment 1 of this invention, (a) is a top view, (b) is a vertical front view, (c) is a bottom view. . It is a perspective view similarly. It is a vertical perspective view which similarly expands and shows the principal part. (A) is a top view of a metal core, (b) is a longitudinal front view of a metal core. It is a figure which shows the example of the resin product which inserted the metal core in the annular part which concerns on Embodiment 2 of this invention, (a) is explanatory drawing of a gate position, (b) is a vertical front view, (c) is a left side. (D) is a right side view FIG. 7 is a diagram illustrating an example in which the gate position is changed from FIG. 6, (a) is an explanatory diagram of the gate position, (b) is a longitudinal front view, (c) is a left side view, and (d) is a right side view.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments shown in the accompanying drawings, and includes all the embodiments that satisfy the requirements described in the claims. It is a waste.
In addition, arrow R in a figure has shown the direction which goes to the radial direction from the center of the resin product which inserted the metal core in the annular part.

Embodiment 1 FIG.
An injection mold 1 according to Embodiment 1 of the present invention shown in FIG. 1 is a resin product in which a cored bar is inserted into an annular portion according to Embodiment 1 of the present invention shown in FIGS. The bearing comb mold holder 11 is molded and melted injected from the sprue 6 into the cavity C between the fixed-side FX mold plate 2 and the movable-side MV mold plate 3 attached to the horizontal injection molding machine. Resin P is injected through runner 7 and gate 8.
The radial positioning pins 4, 4,... And the axial positioning pins 5, 5,. It protrudes inward toward the template 3 of the movable side MV.
Here, the radial positioning pins 4, 4,... Correspond to the punched holes 17A, 17A,... In FIG. .. Corresponding to, for example, 27 holes are provided in the circumferential direction.
It is sufficient that the radial positioning pins 4, 4,... Are two or more and the axial positioning pins 5, 5,... Are three or more, and the number of these is set in accordance with the required specifications. It is a preferred embodiment that the circumference is equally divided according to the above.
The radial positioning pins 4, 4,... And the axial positioning pins 5, 5,... May be manufactured separately from the template 2 and may be press-fitted into the template 2 and implanted. You may make it.
Furthermore, the cross-sectional shape of the axial positioning pins 5, 5,... May be a non-circular cross section such as a square shape or an elliptical shape, and it is not necessary to use the same shape, and the axial length is not required. It only has to be present.

As shown in FIG. 5, the annular cored bar 21 manufactured by, for example, press molding using a metal plate such as a steel plate is engaged with the radial positioning pins 4, 4. Are inserted into the engagement holes 21a, 21a, ..., so that the radial positioning pins 4, 4, ... are engaged with the engagement holes 21a, 21a, ... as shown in FIG. In the combined state, the cored bar 21 is positioned in the radial direction with respect to the template 2 (cavity C).
Further, since the molten resin P injected from the gate 8 flows and fills from the tip end side of the column part in the cavity C opposite to the placed cored bar 21 in the axial direction, the axial direction of the cored bar 21 The end face 21A receives the pressure of the molten resin P flowing into the cavity C from the gate 8, and the axial positioning pins 5, 5,... Are stopped against the axial end face 21B on the back side of the axial end face 21A of the core metal 21. Therefore, the cored bar 21 is positioned in the axial direction (horizontal direction) with respect to the template 2 (cavity C).
Here, the clearance between the radial positioning pins 4, 4,... And the engagement holes 21a, 21a,... Is, for example, about 0.2 mm to 0.5 mm in order to absorb the difference in thermal expansion.
The engagement holes 21a, 21a,... Formed in the core metal 21 with which the radial positioning pins 4, 4,... Engage are not necessarily through holes as shown in FIG. (Indents) are also included.

Then, after the molten resin P is cooled and solidified, the mold plate 3 of the movable side MV is opened from the parting line PL and extruded by the ejector pin 10 to insert the core metal 21 into the annular portion 13. The comb mold holder 11 is taken out from the mold plates 2 and 3 as a molded product.
In this way, the comb holder 11 formed by the injection mold 1 is formed in the annular portion by wrapping the core metal 21 with the resin so that the molten resin materials are joined at the time of injection molding. In addition to having a structure that compensates for the weakness of the weld, the metal contact with the rolling elements is eliminated, so that the sliding characteristics of the resin cage are not impaired.
Further, the comb holder 11 formed by the injection mold 1 has an axial end surface on the back side of the axial end surface 13A of the annular portion 13 in which pockets 11A, 11A,. .., And axial positioning pins 5, 5,... And 17B, 17B,.
Thus, the hole is formed in the axial end surface 13B of the comb-shaped cage 11, and this hole functions as a retaining reservoir for a lubricant such as grease, which is effective in preventing seizure.

According to the injection molding die 1 having the radial positioning pins 4, 4,... And the axial positioning pins 5, 5,. By performing injection molding of a resin product (for example, a roller bearing comb retainer 11) in which a core bar 21 is inserted into the portion 13, the core and the core bar 21 are firmly bonded by wrapping the core bar 21 with resin. Therefore, the reinforcing effect by the cored bar 21 can be enhanced.
Further, the positioning of the cored bar 21 in the radial direction and the axial direction is performed by engaging the radial positioning pins 4, 4,... Into the engagement holes 21 a, 21 a,. Since the axial positioning pins 5, 5,... Are abutted against the axial end surface 21B on the back side of the axial end surface 21A of the cored bar 21 that receives the pressure of the molten resin P, the conventional technique is used. The metal core 21 is not sandwiched and restrained by the holding pins protruding from the fixed mold plate and the movable mold plate.

Therefore, even if the radial positioning pins 4, 4,... And the axial positioning pins 5, 5,... Are separated from the core metal 21 after the resin is solidified, the restoring force of the elastic deformation of the core metal 21 does not occur. Therefore, the accuracy of the resin product (comb cage 11) is not lowered due to the influence of the highly rigid cored bar 21.
Further, since the reinforcing effect and accuracy of the cored bar 21 can be improved, it is not necessary to use an expensive resin material having excellent mechanical properties such as PEEK material, and a general-purpose material such as a polyamide resin is used. Since engineering plastic materials can be used, costs can be reduced.
For example, a resin material obtained by adding 25 weight percent of glass fiber to polyamide resin (PA) such as nylon 66 can be used.

In the above description, the roller bearing comb cage 11 has been described as an example of a resin product in which a metal core is inserted into an annular portion. However, a ball bearing crown cage may be used.
Comb-type cages and crown-type cages, which are resin products in which a core metal is inserted into the annular portion as described above, meet the demands for higher speed rotation of rolling bearings by improving the strength, rigidity and accuracy described above. In addition, since the cost can be reduced while improving such characteristics, the product value can be greatly improved.

Embodiment 2. FIG.
6 and 7 are resin products in which a cored bar is inserted into the annular portion according to the second embodiment of the present invention, between the large-diameter annular portion 14 and the small-diameter annular portion 15. ,... Are shown, and the tapered rollers are inserted into pockets 12A, 12A,.
FIGS. 6 and 7 show examples when the gate position is changed. FIG. 6 shows the gate 9A provided on the axial end face 15B of the small-diameter annular portion 15 or the inner peripheral surface of the small-diameter annular portion 15. FIG. 7 shows an example in which the molten resin is injected into the cavity from the gate 9 </ b> C provided on the outer peripheral surface of the large-diameter annular portion 14.

The tapered roller bearing retainer 12 shown in FIGS. 6 and 7 is manufactured by, for example, press molding using a metal plate such as a steel plate for each of the large-diameter annular portion 14 and the small-diameter annular portion 15. , 16,..., 16,... Are substantially circular ring-shaped metal bars 22, 23 provided with convex portions for reinforcing the vicinity of the bases of the cage. Insert molding is performed by an injection mold having a pin and an axial positioning pin.
That is, in the example of FIG. 6, two or more radial positioning pins that extend in the axial direction and are spaced apart from each other in the engagement holes (not shown) of the core bars 22 and 23 are engaged in the cavity of the injection mold. By aligning, the metal cores 22 and 23 are positioned in the radial direction, and the axial end surfaces 22B and 23B of the metal cores 22 and 23 receiving the pressure of the molten resin flowing into the cavity from the gate 9A or the gate 9B, Positioning in the axial direction (horizontal direction) is achieved by abutting axial positioning pins on the axial end faces 22A and 22A on the back side.
Therefore, in the tapered roller bearing retainer 12 shown in FIG. 6 formed by such an injection mold, the axial end face 14A of the large diameter annular portion 14 and the axial end face 15A of the small diameter annular portion 15 are provided. A radial positioning pin punch hole and an axial positioning pin punch hole 18B, 18B,... And 19B, 19B,.

In the example of FIG. 7, two or more radial positioning pins extending in the axial direction are engaged with engagement holes (not shown) of the core bars 22 and 23 in the cavity of the injection mold. By aligning, the core bars 22 and 23 are positioned in the radial direction, and the axial end faces 22A and 23A of the core bars 22 and 23 receiving the pressure of the molten resin flowing into the cavity from the gate 9C are arranged on the back side. Positioning in the axial direction (horizontal direction) is achieved by stopping the axial positioning pins on the axial end faces 22B and 22B.
Therefore, in the tapered roller bearing retainer 12 shown in FIG. 7 formed by such an injection mold, the axial end face 14B of the large diameter annular portion 14 and the axial end face 15B of the small diameter annular portion 15 are provided. A radial positioning pin punch hole and an axial positioning pin punch hole 18B, 18B,... And 19B, 19B,.

The large-diameter annular portion 14 in which the core bars 22 and 23 are insert-molded in the large-diameter annular portion 14 and the small-diameter annular portion 15 using the injection mold of the second embodiment as described above. The tapered roller bearing retainer 12 having a shape in which the cylindrical portion 15 is connected to the small-diameter annular portion 15 by the column portions 16, 16,... The cage 12 can meet the demand for higher speed rotation of the tapered roller bearing by improving the strength, rigidity and accuracy, and can reduce the cost while improving such characteristics. Product value can be greatly improved.
In addition, in the tapered roller bearing retainer 12 of the second embodiment, for example, 25% by weight of glass fiber is added to polyamide resin (PA) such as nylon 66 in the same manner as the comb retainer 11 of the first embodiment. The resin material etc. which were made can be used.

C Cavity FX Fixed side MV Movable side P Molten resin PL Parting line R Radial direction 1 Injection mold 2, 3 Mold plate 4 Radial positioning pin 5 Axial positioning pin 6 Sprue 7 Runner 8, 9A, 9B, 9C Gate 10 Ejector pin 11 Comb cage for roller bearing (resin product with a core inserted in an annular part)
12 Retainer for tapered roller bearing (resin product with a cored bar inserted in an annular part)
11A, 12A Pocket 13 Annular part 13A, 13B Axial end face 14 Large diameter annular part 14A, 14B Axial end face 15 Small diameter annular part 15A, 15B Axial end face 16 Column parts 17A, 17B, 18B, 19B Core metal 21a Engagement holes 21A, 21B Axial end face 22 Large diameter core metal 23 Small diameter core metal 22A, 22B, 23A, 23B Axial end face

Claims (4)

  Two or more radial positioning pins projecting from the template into the cavity and spaced apart in the circumferential direction and extending in the axial direction, and three or more axial positioning pins spaced in the circumferential direction and extending in the axial direction, An annular cored bar formed with an engagement hole to be engaged with the radial positioning pin was positioned in the radial direction by engaging the radial positioning pin with the engagement hole, and flowed into the cavity. Resin with a cored bar inserted in an annular part that is positioned in the axial direction by abutting the axial positioning pin on the axial end face on the back side against the axial end face of the cored bar that receives the pressure of the molten resin Mold for product injection molding.   A product is molded by filling the cavity with molten resin in a state where the cored bar is accommodated in the cavity using the injection mold according to claim 1. A method for manufacturing resin products with a cored bar inserted in the part.   A comb-type cage or a crown-type cage manufactured by the method for manufacturing a resin product according to claim 2, wherein the radial positioning pin and the axial positioning pin are provided on an axial end surface on the back side of the axial end surface on which the pocket is formed. A resin retainer with a cored bar inserted in an annular part with pin holes. A tapered roller bearing retainer having a shape in which a large-diameter annular portion and a small-diameter annular portion manufactured by the resin product manufacturing method according to claim 2 are connected by a column portion, and the large-diameter annular ring An annular cored bar is inserted into each of the portion and the small-diameter annular portion, and both the large-diameter annular portion and the small-diameter annular portion are arranged on the same axial end surface of both axial end faces. A resin retainer in which a cored bar is inserted into an annular portion in which a hole for a radial positioning pin and an axial positioning pin is formed.

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