MOLDED RESIN ARTICLE AND METHOD FOR MANUFACTURING SAME

Abstract

A molded resin article and a method of manufacturing a molded resin article that suppresses generation of portions of reduced bonding strength while suppressing separation at the interface between a bond portion (secondary molding resin) on the one hand and a first body and a second body on the other. The molded resin article has a first contact surface formed perpendicular to the main surface of the first body and contacting the second body, a second contact surface formed perpendicular to the main surface of the second body and contacting the first body, and a bond portion bonding together the first body and the second body, formed by injecting molten resin into a resin channel formed by contacting the first contact surface against the second body and contacting the second contact surface against the first body and solidifying the molten resin.

Claims

1. A molded resin article comprising: a molded first body having a main surface; and a molded second body having a main surface, the molded resin article joined into a single unit by disposing the main surface of the first body and the main surface of the second body facing each other, a first contact surface contacting the second body formed perpendicular to the main surface of the first body, a second contact surface formed perpendicular to the main surface of the second body and contacting the first body, a bond portion bonding together the first body and the second body, the bond portion formed by injecting molten resin into a resin channel formed by the first contact surface contacting the second body and the second contact surface contacting the first body and solidifying the molten resin.

2. The molded resin article according to claim 1, further comprising: a first concave fluid passage formed in the first body; and a second concave fluid passage formed in the second body, the first and second concave fluid passages forming a single fluid passage by joining the first and second bodies into a single unit, the first contact surface that contacts the second body formed perpendicular to the main surface of the first body, in which the first concave fluid passage is formed, the second contact surface that contacts the first body formed perpendicular to the main surface of the second body, in which the second concave fluid passage is formed.

3. The molded resin article according to claim 1, wherein the first contact surface and the second contact surface are not coplanar.

4. The molded resin article according to claim 1, wherein a channel cross-section orthogonal to a direction in which resin flows through the resin channel is formed in a rectangular shape.

5. The molded resin article according to claim 4, wherein, in the channel cross-section, corner portions of sides of the resin channel not contacting the first and second bodies are formed in an arc shape.

6. A method of manufacturing the molded resin article according to claim 1, comprising: setting a first molded body and a second molded body in a mold; forming the resin channel by moving the mold parallel to the first contact surface and the second contact surface, contacting the first contact surface against the second body, and contacting the second contact surface against the first body; injecting molten resin into the resin channel; and removing the first body and the second body as a single unit from the mold after the molten resin injected into the resin channel solidifies and the bond portion is formed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG. 1 is a plan view showing a first embodiment of a molded resin article according to the present invention;

[0051] FIG. 2 is a front view of the molded resin article shown in FIG. 1;

[0052] FIG. 3 is a cross-sectional view taken along line I-I of FIG. 1;

[0053] FIG. 4 is an enlarged view of the principal parts shown in FIG. 3;

[0054] FIG. 5 is a view showing a state of growing in a direction different from a portion of reduced bonding strength shown in FIG. 4;

[0055] FIG. 6 is a perspective view showing a conventional manifold device;

[0056] FIG. 7 is a cross-sectional view for explaining conventional DSI molding;

[0057] FIG. 8 is a process chart when conventional DSI molding is applied to a manifold device;

[0058] FIG. 9 is a perspective view showing a manifold device manufactured by the DSI molding method shown in FIG. 8; and

[0059] FIG. 10 is a cross-sectional view taken along line II-II shown in FIG. 9.

DETAILED DESCRIPTION OF EMBODIMENTS

[0060] Hereinafter, the molded resin article according to the present invention will be described with reference to FIGS. 1 to 5 taking the manifold device as an example. However, the present invention is not limited to the manifold device, but can be applied to molded resin articles in general.

[0061] As shown in FIGS. 1 to 3, manifold device 1 is composed of a first body 1A and a second body 1B.

[0062] The first body 1A is molded so that a pair of coolant intake pipes 2, 3 that take in coolant respectively face in the same direction.

[0063] As shown in FIG. 1, the pair of coolant intake pipes 2, 3 communicate with each other in the manifold device 1. A fluid passage 4 for collecting coolant from the pair of coolant intake pipes 2, 3 is formed thereat.

[0064] This fluid passage 4 is formed by combining a first concave fluid passage 4a formed in the first body 1A and a second concave fluid passage 4b formed in the second body 1B. That is, by putting the first and second bodies 1A, 1B together, the first and second concave fluid passages 4a, 4b form a single fluid passage 4.

[0065] Further, the first concave fluid passage 4a forming surface side of the first body 1A is referred to as the main surface F1 of first body 1A. Similarly, the second concave fluid passage 4b forming surface side of the second body 1 B is referred to as the main surface F2. Therefore, putting together the main surface F1 side of the first body 1A and the main surface F2 side of the second body 1B forms the first and second concave fluid passages 4a and 4b into the one fluid passage 4.

[0066] In the first body 1A, a connecting pipe 5 to a radiator (not shown) is formed in a state of communicating with the fluid passage 4 at a substantially central portion of the fluid passage 4. That is, the connecting pipe 5 to the radiator is formed so that its communication opening 5a faces in the same direction as the openings 2a, 3a of the coolant intake pipes 2, 3.

[0067] A connecting pipe 6 having a communication opening 6a leading to a heater core (not shown) used as a heat exchanger for interior heating is formed at a substantially central portion of the first body 1A. This connecting pipe 6 is formed upward from the center portion of the second body 1A.

[0068] Further, a connecting pipe 7 having a communication opening to an ATF warmer is formed in communication with the fluid passage 4 in a direction opposite the side of the first body 1A on which the coolant intake pipe 2 is arranged. As is well known, this is used to shorten the warm-up time of the automatic transmission AT and to improve fuel economy just after start-up.

[0069] A connecting pipe 8 having a communication opening 8a to an EGR cooler facing upward is formed in communication with the fluid passage 4 on the side of the first body 1A on which the coolant intake pipe 3 is arranged. As is well known, this is used to cool the engine's exhaust gas for recirculation.

[0070] In the first body 1A, a contact part 9 abutting the second body 1B is provided. Similarly, in the second body 1B, a contact part 10 abutting the first body 1A is provided.

[0071] Further, as shown in FIG. 4, the contact part 9 is provided with a first contact surface 9a formed perpendicular to the main surface F1 in which the first concave fluid passage 4a is formed. A side wall 9b is formed parallel to the main surface F1 from the contact surface 9a so that the contact surface 9a protrudes. Further, a contacted part 9c is formed extending from the lower end of the side wall 9 b and perpendicular to the main surface F1.

[0072] Similarly, the contact part 10 is provided with a second contact surface 10a formed perpendicular to the main surface F2 in which the second concave fluid passage 4b is formed. A side wall 10b is formed parallel to the main surface F2 from the contact surface 10a so that the contact surface 10a protrudes. Further, a contacted parted 10c is formed extending from the lower end of the side wall 10b and perpendicular to the main surface F2.

[0073] Then, the first contact surface 9a abuts (makes contact with) the contacted surface 10c of the second body 1B and the second contact surface 10a abuts (makes contact with) the contacted surface 9c of the first body 1A, by which a resin channel 11 is formed between the first contact surface 9a and the second contact surface 10a.

[0074] As shown in FIGS. 1 and 3, a resin injection port 13 for injecting molten resin into the resin channel 11 is provided in the first body 1A and the second body 1B.

[0075] Then, molten resin is injected from the resin injection port 13 into the resin channel 11 and solidified to form a bond portion 12 bonding the first body 1A and the second body 1B together.

[0076] Note that when the molten resin is injected into the resin channel 11 and the bond portion 12 is secondarily formed, a so-called core N is disposed in the fluid passage 4 while a mold is disposed on the outside of the first body 1A and the second body 1B.

[0077] In this way, since the contact parts 9, 10 are sandwiched between the core N and the mold, deformation of the contact parts 9, 10 due to the injection pressure when the molten resin is injected into the resin channel 11 is suppressed.

[0078] Further, as shown in FIGS. 3 and 4, the first contact surface 9a and the second contact surface 10a are not on the same plane but are formed at positions offset from each other.

[0079] Thus, since the first contact surface 9a and the second contact surface 10a are not on the same plane but are offset from each other, there is little residual stress at the time of secondary molding and a portion of reduced bonding strength C is not easily generated. In the event that the portion of reduced bonding strength C is generated in the bond portion 12 and a void occurs, this proceeds first from the inside (central portion) of the bond portion 12 part (secondary molding resin) 12 to an interface D between the first body 1A and the second body 1B. Subsequently, the portion of reduced bonding strength C proceeds to the first contact surface 9a and the second contact surface 10a.

[0080] Therefore, compared to an arrangement in which the first contact surface 9a and the second contact surface 10a are coplanar, the chance of defective airtightness, etc., in the manufacturing process is reduced.

[0081] Note that, as shown in FIG. 5, even if the portion of reduced bonding strength C arises and voids are generated and travel obliquely, since the first contact surface 9a and the second contact surface 10a are not on the same plane but offset from each other, the chance of defective airtightness, etc., in the manufacturing process is reduced.

[0082] In addition, a cross-section of the flow channel orthogonal to the resin flowing direction of the resin channel 11 is formed in a rectangular shape. Note that the corner portions 9d, 10d of the channel cross-section perpendicular to the direction of resin flow through the resin channel 11 are preferably arc-shaped.

[0083] As a result of forming the corner portions 9d, 10d in the shape of an arc, when injecting the molten resin into the fluid passage, the pressure component of the molding pressure (injection pressure) that acts on the arc-shaped corner portion is dispersed toward the contact surface. That is, the molding pressure (injection pressure) is uniformly dispersed, the strength is increased due to the thick wall, and a necessary and sufficient contact area can be secured. Further, unless the molding pressure is uniformly dispersed, residual stress is generated, and the bonding surfaces between the primary molding surface and the secondary molding resin separate, possibly leading to leakage.

[0084] Note that when the corners are formed as right angles, the molten resin does not run to the tip of the corner portion, a cavity is formed at the corner portion, the proper contact area cannot be secured, and there is a risk that an improvement in bonding strength cannot be expected.

[0085] As described above, when joining the main surface F1 of the first body 1A and the main surface F2 of the second body 1B, the contact surfaces 9a and 10a of the first and second bodies are parallel to the pressing direction P of the molds. Since the contact surfaces of the first and second bodies do not strongly abut each other, the residual stress in the contact surfaces 9a and 10a of the first and second bodies can be suppressed.

[0086] As a result, separation at the interface between the bonding interface 12 (secondary molding resin) and first body 1A and second body 1B can be suppressed, and durability is further improved.

[0087] In addition, when the secondary molding resin (molten resin 11 in the resin channel) is cooled and the bond portion 12 is formed, contraction accompanying cooling of the secondary molding resin occurs. Because this cooling of the molten resin starts from the outside, even in the event that the portion of reduced bonding strength C is generated in the interior (the center section) of the bond portion 12 which is separated from the interface D and voids are generated in the interface D, these voids extend to the interface D and ultimately connect to the contact surface 9a, 10a.

[0088] However, as described above, it is possible to suppress separation at the bond portion 12 (secondary molding resin) and the interface D between the first body 1A and the second body 1B, so that the chance of defective airtightness, etc., in the manufacturing process is reduced.

[0089] A method of manufacturing the molded resin article will now be described. Since the general outline of the method for manufacturing of the manifold device is the same as the conventional one, it will be explained insofar as necessary, with reference to FIG. 8.

[0090] First, as shown in FIG. 8 (a), first bodies 1A and 1B are formed by primary molding. Next, the molded first body 1A and second body 1B are placed facing each other and set in the mold (see FIG. 8 (c)). At this time, the first contact surface 9a faces the second body 1B and the second contact surface 10a faces the first body 1A.

[0091] Note that the mold used for the primary molding maybe used for the mold in which the first body 1A and second body 1B are placed facing each other, or a mold different from the mold used for primary molding may be used.

[0092] Subsequently, one of the molds is moved parallel to the first contact surface 9a and the second contact surface 10a to form the resin channel 11.

[0093] At this time, since the first contact surface 9a is perpendicular to the main surface F1 of the first body 1A and the second contact surface 10a is formed perpendicular to the main surface F2 of the second body 1B, the first contact surface 9a slides over the contacted surface 10c of the second body 1B and the second contact surface 10a slides over the contacted surface 10c of the first body 1A to form the resin channel 11.

[0094] Subsequently, melted synthetic resin is injected into the resin channel 11 from the injection port 13. Then, by solidifying the molten resin injected in the resin channel 11, the bond portion 12 joining the first body 1A and the second body 1B is formed.

[0095] Thereafter, by removing the first body 1A and the second body 1B now united as a single unit from the mold, the manifold device 1 is completed.

[0096] With the method for manufacturing according to the present invention, when the first body 1A and the second body 1B are joined into a single unit, because the first contact surface 9a and second contact surface 10a are formed parallel to the pressing direction P of molds, the contact surfaces 9a and 10a slide over the contacted surfaces 10c and 9c and the contact surfaces 9a and 10a of the first and second bodies are not strongly brought into contact with each other.

[0097] Therefore, the residual stress in the contact parts 9,10 of first and second bodies 1A, 1B can be maximally suppressed, separation at the interface D between the bond portion 12 (secondary molding resin) and the first body 1A and second body 1B can be suppressed, and leakage of coolant to the outside can be suppressed.

[0098] In the foregoing embodiment, a description has been given of a manifold device as an example of the molded resin article. However, the present invention is not particularly limited thereto and can be used whenever any primary molded articles are joined together into a single unit, and is applicable as well to joining together molded articles having a simple shape into a single unit.

[0099] In addition, as a so-called secondary molding (forming the bond portion) in which molded articles are joined together, the mold used for primary molding may be used, or alternatively another mold may be used.

DESCRIPTION OF REFERENCE CHARACTERS

[0100] 1 Manifold device [0101] 1A First body [0102] 1B Second body [0103] 4 Fluid passage [0104] 4a First concave fluid passage [0105] 4b Second concave fluid passage [0106] 9 First body contact part [0107] 9a Contact surface [0108] 9b Side wall [0109] 9c Contacted surface [0110] 10 Second body contact part [0111] 10a Contact surface [0112] 10b Side wall [0113] 10c Contacted surface [0114] 11 Resin channel [0115] 12 Bond portion [0116] 13 Resin injection port [0117] C Portion of reduced bonding strength [0118] D Interface [0119] F1 Main surface of the first body [0120] F2 Main surface of the second body