WO2015075915A1

WO2015075915A1 - Insert-molded product and mold and method of manufacturing

Info

Publication number: WO2015075915A1
Application number: PCT/JP2014/005718
Authority: WO
Inventors: Ryuichi OKUMOTO; Yasunori Takeuchi; Naotaka Nishikawa; Masaki Kobayashi; Makoto Yoshida
Original assignee: Toyota Jidosha Kabushiki Kaisha; Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho; Tsuda Industries Co., Ltd.; Mannoh Kogyo Co., Ltd.
Priority date: 2013-11-20
Filing date: 2014-11-13
Publication date: 2015-05-28
Also published as: JP2015100917A

Abstract

Provided is an insert-molded product having a part of the insert pin projecting from the resin eliminated, a mold for an insert-molded product, and a method of manufacturing an insert-molded product. Since a projecting component 20 is provided with opening gaps 32a, 32b between resin 29 and an insert pin 28 and at least at one end of the insert pin 28, a projection 46 of a first mold 38 and a projection 48 of a second mold 40 are formed such that the gaps 32a, 32b are formed at the time of injection molding of the projecting component 20. Since the insert pin 28 is held by utilizing the projections 46, 48, the structure of the insert pin 28 projecting from the resin 29 can be eliminated.

Description

[Title established by the ISA under Rule 37.2]INSERT-MOLDED PRODUCT AND MOLD AND METHOD OF MANUFACTURING

The present invention relates to an insert-molded product, a mold for an insert-molded product, and a method of manufacturing an insert-molded product and particularly to miniaturization of an insert-molded product.

An insert-molded product is known that is integrally molded from an insert pin and resin by injecting the resin while the insert pin is held in a mold. Patent Document 1 describes a method of manufacturing the insert-molded product. Specifically, in the described method of insert molding, while the insert pin is attached to a holding hole formed in a first mold, a second mold is combined to form a cavity (hollow space) inside and a molten molding material is injected into the cavity to form an insert-molded product.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-55200 Patent Document 2: Japanese Laid-Open Patent Publication No. 2006-170260 Patent Document 3: Japanese Laid-Open Patent Publication No. 06-174060

In the method of insert molding of Patent Document 1, since the insert pin is held by the holding hole formed in the mold, the manufactured product (insert-molded product) has a shape with the insert pin projected. However, if a projected part of the insert pin is unnecessary, this part increases weight and makes costs higher. Moreover, when the manufactured product is assembled, an extra gap from a peripheral component must be ensured to prevent interference between the insert pin and the peripheral component.

The present invention was conceived in view of the situations and it is therefore an object of the present invention to provide an insert-molded product integrally molded from an insert pin and resin by injecting the resin while the insert pin is held in a mold, the insert-molded product having a part of the insert pin projecting from the resin eliminated, a mold for an insert-molded product, and a method of manufacturing an insert-molded product.

To achieve the object, the first aspect of the invention provides an insert-molded product (a) integrally molded from an insert pin and resin by injecting the resin while the insert pin is fixed in a mold, wherein (b) an opening gap is formed between the resin and the insert pin at least at one end of the insert pin.

Consequently, since the insert-molded product is provided with the opening gaps between the resin and the insert pin and at least at one end of the insert pin, a mold is formed such that the gaps are formed at the time of manufacturing the insert-molded product. Since the insert pin is held by utilizing a part for forming the gaps of the mold, the structure of the insert pin projecting from the resin can be eliminated. Therefore, as compared to an insert-molded product with a conventional structure of the insert pin projecting from the resin, costs and weight can be prevented from increasing due to projection of the insert pin from the resin.

To achieve the object, the second aspect of the invention provides a mold for an insert-molded product (a) integrally molded from an insert pin and resin by injecting the resin while the insert pin is fixed in the mold, wherein (b) a projection for forming the gap is formed such that an opening gap is formed between the resin and the insert pin at least at one end of the insert pin. Since the insert pin is held by the projection formed on the mold, this eliminates the structure in which the insert pin is held by a holding hole formed in a conventional mold. Therefore, the structure of the insert pin projecting from the resin can be eliminated in the insert-molded product, and as compared to a conventional insert-molded product with the insert pin projecting from the resin, costs and weight can be prevented from increasing due to projection of the insert pin from the resin.

To achieve the object, the third aspect of the invention provides a method of manufacturing an insert-molded product (a) integrally molded from an insert pin and resin by injecting the resin while the insert pin is fixed in a mold, wherein (b) a projection for forming the gap is formed on the mold such that an opening gap is formed between the resin and the insert pin at least at one end of the insert pin, and wherein (c) after the mold is fixed while the insert pin is held by the projection, the resin is injected into the mold. Consequently, since the projections formed on the mold hold the insert pin and the resin is injected into the mold in this state, the insert-molded product can be molded that has a structure without projection of the insert pin from the resin.

Preferably, the gap is formed between each of both ends of the insert pin and the resin. As a result, since the both ends of the insert pin can be held by the mold, holding accuracy is improved when the insert pin is held by the mold, and dimension accuracy of the insert-molded product can be improved.

Preferably, the projection has an annular shape and the insert pin is fitted to an inner circumferential portion of the annular shape. Since the insert pin is fitted to the inner circumferential portion of the annular shape, support accuracy of the insert pin is made higher.

Fig. 1 is a schematic of a shift operation device switching a shift position of a vehicle automatic transmission that is an example of the present invention. Fig. 2 is an enlarged view of a control lever of Fig. 1. Fig. 3 is a view of the control lever taken in the direction of an arrow A of Fig. 2. Fig. 4 is a cross-sectional view of a projection taken along a line B-B of Fig. 3. Fig. 5 depicts a state of an insert pin fixed by a mold at the time of injection molding of the control lever of Fig. 2. Fig. 6 is a flowchart for explaining a manufacturing process of the control lever of Fig. 2 by injection molding.

An example of the present invention will now be described in detail with reference to the drawings. In the following example, the figures are simplified or deformed as needed and portions are not necessarily precisely depicted in terms of dimension ratio, shape, etc.

Fig. 1 is a schematic of a shift operation device 10 switching a shift position of a vehicle automatic transmission that is an example of the present invention. A shift lever 14 operated by a driver projects from a lever assy 12 acting as a main body of the shift operation device 10. The shift lever 14 is configured to be rotatable around a rotation shaft not depicted and switchable to a P-position (parking), an R-position (reverse), an N-position (neutral), a D-position (drive), etc. The shift lever 14 is operatively coupled to a control lever 16 indicated by a broken line and housed in the lever assy 12.

Fig. 2 is an enlarged view of the control lever 16. The control lever 16 is formed into a substantially triangular shape and is rotatable around a rotation axis C. When the shift lever 14 is operated to a predetermined shift position, the control lever 16 is rotated to a rotational position corresponding to the shift position. The control lever 16 is disposed with a circular columnar projecting component 20 perpendicularly projecting from a main body 18 thereof formed into a substantially triangular shape. The control lever 16 is made of resin except an insert pin 28 described later.

Fig. 3 is a view of the control lever 16 taken in the direction of an arrow A of Fig. 2. As depicted in Fig. 3, the main body 18 is formed into a step shape and is disposed with the circular columnar projecting component 20 extending in parallel with the rotation axis C at an upper end position in Fig. 3. The projecting component 20 projects from a cutout 22 formed in the lever assy 12 depicted in Fig. 1 to the outside of the lever assy 12 and is coupled via a coupling member 24 to a shift cable 26. The shift cable 26 is operatively coupled to the vehicle automatic transmission not depicted.

Fig. 4 is a cross-sectional view of the projecting component 20 taken along a line B-B of Fig. 3. Although not depicted in Fig. 3, Fig. 4 also includes a cross sectional view of the coupling member 24 depicted in Fig. 1. As depicted in Fig. 4, the projecting component 20 is formed into a circular columnar shape and has a tip portion slightly bulging in the radial direction. The insert pin 28 made of metal such as iron is housed in an inner circumferential side of the projecting component 20, and an outer circumferential side thereof is made of resin 29. Since the insert pin 28 is housed, strength of the projecting component 20 is ensured. The insert pin 28 is provided with a radially extending circular-plate-shaped flange 30 and is therefore prevented from dropping off from the projecting component 20.

Annular gaps

32a and 32b each having an opening end portion are formed between an outer circumferential surface of both axial ends of the insert pin 28 and the resin 29 covering the insert pin 28. The

gaps

32a, 32b are formed by a mold when the projecting component 20 (the control lever 16) is molded by injection molding. The molding of the projecting component 20 (the control lever 16) will be described later. The projecting component 20 corresponds to an insert-molded product of the present invention.

The coupling member 24 made of metal is fitted to the outer circumferential side of the projecting component 20. The coupling member 24 is provided with a through-hole 34 for fitting to the projecting component 20, and a bush 36 made up of an elastic member such as resin is fitted to an inner circumferential surface of the through-hole 34. The coupling member 24 is press-fitted from a tip side of the projecting component 20 and, since an inner diameter of the bush 36 becomes smaller than an outer diameter of the tip portion of the projecting component 20 after the press-fitting, the coupling member 24 is prevented from coming off.

Since the projecting component 20 of this example is not in a conventional shape with a reinforcing insert pin projecting from resin, the insert pin 28 becomes shorter, resulting in a lighter weight and reduced manufacturing costs and, after assembly of the control lever 16, a space occupied by the control lever 16 becomes smaller. The conventional shape with an insert pin projecting from resin is formed because the insert pin is held by a holding hole formed in a mold at the time of injection molding. A method of manufacturing the projecting component 20 having the shape of the example will hereinafter be described.

Fig. 5 depicts a state of the insert pin 28 fixed by a mold at the time of injection molding of the projecting component 20 (the control lever 16). The insert pin 28 is housed in a space surrounded by first to fourth molds 38 to 44. Resin is injected in a pressurized state in the direction indicated by an arrow of Fig. 5 into a space formed between the first to fourth molds 38 to 44 and the insert pin 28. The first mold 38 is provided with a cylindrical projection 46 perpendicularly projecting from a mating surface 50 for the third and

fourth molds

42 and 44. The second mold 40 is provided with a cylindrical projection 48 perpendicularly projecting from a bottom surface 52 thereof. The insert pin 28 is held (fixed) at the both ends by the

projections

46 and 48. Since the resin is injected while the insert pin 28 is held by the

projections

46 and 48, the insert pin 28 is prevented from projecting from the resin. Since the projection 46 of the first mold 38 and the projection 48 of the second mold 40 are formed, the

gaps

32a and 32b are formed after injection molding. The first mold 38 and the second mold 40 correspond to a mold for an insert-molded product provided with a projection for forming a gap of the present invention.

Fig. 6 is a flowchart for explaining a manufacturing process of the projecting component 20 (the control lever 16) by injection molding. First, at step S1, as depicted in Fig. 5, while the insert pin 28 is held (fixed) by the projection 46 of the first mold 38 and the projection 48 of the second mold 40, the third mold 42 and the fourth mold 44 are combined therewith and the molds are fixed in a mold closing process. At step S2, after the mold closing of the molds, resin is injected in an injecting process. At step S3, the resin is cooled for a predetermined time after injection to solidify the resin in a cooling process. At step 4, the molds are opened in a mold releasing process, and the projecting component 20 (the control lever) is molded. Since the resin is injected while the insert pin 28 is held by the

projections

46 and 48, the component is integrally molded from the insert pin 28 and the resin, and the insert pin 28 is prevented from projecting from the resin.

As described above, according to this example, since the projecting component 20 is provided with the opening

gaps

32a, 32b between the resin 29 and the insert pin 28 and at least at one end of the insert pin 28, the projection 46 of the first mold 38 and the projection 48 of the second mold 40 are formed such that the

gaps

32a, 32b are formed at the time of injection molding of the projecting component 20. Since the insert pin 28 is held by utilizing the

projections

46, 48, the structure of the insert pin 28 projecting from the resin 29 can be eliminated. Therefore, as compared to a manufactured product with a conventional structure of the insert pin 28 projecting from the resin 29, costs and weight can be prevented from increasing due to projection of the insert pin 28 from the resin.

According to this example, since the

projections

46, 48 hold the insert pin 28 and the resin 29 is injected into the mold in this state, the projecting component 20 can be molded that has a structure without projection of the insert pin 28 from the resin 29.

Although the example of the present invention has been described in detail with reference to the drawings, the present invention is applied in other forms.

For example, although the

projections

46, 48 are cylindrically formed in the example, this is not a limitation of the shape of the projections. For example, the

projections

46, 48 may not necessarily be continuous and may circumferentially be formed intermittently at regular angular intervals. Therefore, the shape of the

projections

46, 48 may be changed as needed as long as the insert pin 28 can be held.

Although the insert pin 28 is formed into a circular columnar shape in the example, the shape is not necessarily limited to a circular columnar shape and may be changed as needed to a square columnar shape etc. The shape of the projections is accordingly changed as needed. Therefore, the shape of the projections is changed as needed such that the insert pin 28 can be held.

Although the

gaps

32a, 32b are formed at the both ends of the insert pin 28 in the example, the projecting component 20 may have a structure in which either one of the

gaps

32a, 32b is formed as long as the insert pin 28 can be held on one axial side. Therefore, either the

projection

46 or 48 may be formed as long as the insert pin 28 can be held by either the projection 46 of the first mold 38 or the projection 48 of the second mold 40.

Although the insert pin 28 is made of iron in the example, material other than iron may be used as long as the projecting component 20 can be reinforced.

Although the projecting component 20 is formed by four molds from the first mold 38 to the fourth mold 44 in the example, the number of the molds is not particularly limited.

The above description is merely an embodiment and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

16: control lever
20: projecting component (insert-molded product)
28: insert pin
32a: gap
32b: gap
38: first mold (mold)
40: second mold (mold)
42: third mold (mold)
44: fourth mold (mold)
46: projection
48: projection

Claims

An insert-molded product integrally molded from an insert pin and resin by injecting the resin while the insert pin is fixed in a mold, wherein
an opening gap is formed between the resin and the insert pin at least at one end of the insert pin.
A mold for an insert-molded product integrally molded from an insert pin and resin by injecting the resin while the insert pin is fixed in the mold, wherein
a projection for forming the gap is formed such that an opening gap is formed between the resin and the insert pin at least at one end of the insert pin.
A method of manufacturing an insert-molded product integrally molded from an insert pin and resin by injecting the resin while the insert pin is fixed in a mold, wherein
a projection for forming the gap is formed on the mold such that an opening gap is formed between the resin and the insert pin at least at one end of the insert pin, and wherein
after the mold is fixed while the insert pin is held by the projection, the resin is injected into the mold.