BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a resin molded article according to the invention.
FIG. 2 is a plan view of a primary molded article of the resin molded article.
FIG. 3 is a section along III-III of FIG. 1.
FIG. 4 is a section showing a state where a first rib is supported by supporting portions during the insert molding of the resin molded article.
FIG. 5 is an exploded perspective view of a collar, a metal flat plate and a lower die at a position where a positioning projection is provided.
FIG. 6 is a plan view showing a state where the collar and the metal flat plate are set in the lower die.
FIG. 7 is a section showing a state where the collar is in an inclined posture in the height range of guiding projections.
FIG. 8 is a section showing a state where the collar and the metal flat plate are set in proper postures in the lower die.
FIG. 9 is a section along IX-IX of FIG. 1.
FIG. 10 is a section showing a state where a collar is in an inclined posture in the height range of a positioning projection in a prior art construction.
FIG. 11 is a section showing a state where the collar is deformed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A resin molded article according to the invention is identified by the numeral 1 in FIG. 1 and is to be installed inside an automotive transmission. The resin molded article 1 has a laterally long shape and is formed by insert molding so that a primary molded article 10, tubular collars 40 and a substantially flat metal plate 50 are molded integrally as inserts in a secondary molded article 30. Additionally, the primary molded article 10 has at least one busbar 2 embedded therein The flat metal plate 50 is formed with through holes 51 having a smaller diameter than the inner diameter of the collars 40 as shown, and the collars 40 are arranged at the lower side of the flat metal plate 50 at positions substantially coaxial with the holes 51. The holes 51 are for insertion of unillustrated bolts or the like, and the resin molded article 1 is fixed to a valve unit or the like via the collars 40 by inserting bolts from a side of the flat metal plate 50 and spirally engaging them with internal recesses or threads formed in the valve unit or the like arranged inside a transmission casing. It should be noted that reference is made herein to a transverse direction in FIG. 1, a vertical direction in FIG. 1 and a direction normal to the plane of FIG. 1 for a longitudinal direction LD, a width direction WD and a vertical direction VD. Additionally, the front side of the plane of FIG. 1 is an upper side.
The primary molded article 10 is made e.g. of synthetic resin or a synthetic resin containing a reinforcement (e.g. 6,6 nylon containing glass fibers), and includes a wide primary molded portion 11 and three busbars 2 arranged therein as shown in FIG. 2. Ends of the busbars 2 at one side are collected at one position, and project out to the left from the left surface of the primary molded portion 11. A terminal surface 13 is defined at the end of the primary molded article 10 where the ends of the busbars 2 are drawn out. One of the busbars 2 defines a first circuit 2A extending along a first extending to the right substantially along the longitudinal direction LD from the end collected side, and the remaining two busbars 2 define second circuits 2B extending substantially normal to the first extending direction of the first circuit 2A and substantially along the width direction WD from the end collected side. A substantially rectangular terminal 3 is formed near the end of each busbar 2. A through hole 3A penetrates the terminal 3 in the vertical direction VD, and is used to rivet or otherwise fix the terminal 3 to an unillustrated mating terminal.
Ribs 12 are formed substantially along the longitudinal direction LD on the upper surface of the primary molded article 10. A surface 15 where this ribs 12 are formed is adjacent to a surface 14 facing a gate 62 of a molding die 60 during the insert molding, as shown in FIG. 4 and also is adjacent to the terminal surface 13, as shown in FIG. 2. As shown in FIG. 9, the ribs 12 include first ribs 12A and second ribs 12B having different heights. More particularly four first ribs 12A and five second ribs 12B are arranged alternately. It should be noted that the rib 12 at a position substantially corresponding to the first circuit 2A of the busbar 2 with respect to vertical projecting direction of the rib 12, as shown in FIG. 3.
Supports 61 are provided intermittently along the longitudinal direction LD on a cavity inner surface 63 of an upper die 60A of the molding die assembly 60 and project towards the first ribs 12A. As shown in FIG. 4, two supports 61 are formed adjacent to the first ribs 12A and sandwich the first ribs 12A at opposite widthwise surfaces that are substantially normal to a resin injection direction from the gate 62. The leading end surfaces of the supports 61 contact the rib formation surface 15, and the leading end surfaces of the first ribs 12A contact a back surface 61A defined between the supports 61. In this way, the supports 61 support the ribs 12A substantially along the vertical direction VD and the width direction WD during the insert molding, and parts supported by the supports 61 are exposed to the outside after the insert molding (see FIG. 1). The leading end surfaces of the first ribs 12A are substantially flush with the outer/upper surface of the secondary molded portion 30 after the insert molding, as shown in FIG. 3.
The second ribs 12B have a smaller height than the first ribs 12A. Specifically, the height of the second ribs 12B is shorter than a distance between the rib formation surface 15 and the cavity inner surface 63 of the molding die 60 facing this surface 15 during the insert molding. Accordingly, as shown in FIG. 1, the second ribs 12B are embedded in the secondary molded portion 30 after the insert molding.
As shown in FIG. 5, positioning projections 64 project from the bottom surface of a lower die 60B of the molding die assembly 60 and are used to position the collars 40 in the lower die 60B. Each positioning projection 64 has a cylindrical or contoured shape substantially inscribing in a circle and substantially corresponding to the inner shape of the collars 40. The diameter of each positioning projection 64 is slightly smaller than the inner diameter of the collars 40 and slightly larger than the diameter of the holes 51 of the flat metal plate 50. The height of the positioning projections 64 is substantially equal to that of the collars 40. A shaft 65 projects up coaxially with the positioning projection 64 at the upper end of each positioning projection 64. The diameter of the shaft 65 is slightly smaller than the diameter of the holes 51 of the flat metal plate 50, so that the shafts 65 can be accommodated in the holes 51 of the flat metal plate 50.
Four guiding projections 66 are formed on the outer circumferential surface of each shaft 65 and extend substantially radially out from the axial center of the shaft 65 while being spaced apart at substantially even intervals of about 90°. The guiding projections 66 are connected with both the upper end of the positioning projection 64 and the outer circumferential surface of the shaft 65. Guiding surfaces 66A are defined at the outer circumference of the guiding projections 66 and are substantially continuous and flush with the outer circumferential surface of the positioning projection 64. On the other hand, the flat metal plate 50 is formed with notches 52 that extending substantially radially out from the inner circumferential surface of each hole 51. Thus, the flat metal plate 50 can be placed atop the collars 40 after the collars 40 are set on the positioning projections 64, and the guiding projections 66 are accommodated into the respective notches 52. The extension of the notches 52 is set so that the leading ends of the notches 52 are more outward than the inner circumferential surfaces of the collars 40, as shown in FIG. 6.
The primary molded article 10, the collars 40 and the metal flat plate 50 are set in the lower die 60B of the molding die assembly 60. The collars 40 then are passed over the outer peripheries of the guiding surfaces 66A of the guiding projections 66 and are fit onto the positioning projections 64. The inner circumferential surfaces of the collars 40 contact the guiding surfaces 66A to position the collars 40 regardless of how inclined the collars 40 are when being fitted on the guiding projections 66. Therefore, the collars 40 can be fit smoothly onto the positioning projections 64.
The inner circumferential surface of the collar 40 might get caught by the guiding surface 66A and tilt as shown in FIG. 7. In such a case, the collar 40 might possibly be deformed if the flat metal plate 50 is set with the collar 40 inclined and the molding die is closed. However, the collar 40 would take such an inclined posture at a distance from the bottom surface of the lower die 60B, and such an inclined posture on the positioning projection 64 would be recognized easily as an improper posture.
Even if the insert molding is carried out with the collar 40 deformed, the deformation of the collar 40 can be known by comparing and checking amounts of the collars 40 exposed at the notches 52 at the four positions. Accordingly, there is no likelihood of producing a defective article. Further, upon placing the flat metal plate 50 atop the collars 40, the shafts 65 can be fit at least partly inside the holes 51 while the guiding projections 66 are accommodated into the notches 52 (see FIG. 6) even if the positional precision of the holes 51 is poor, because the notches 52 are longer than the projecting amounts of the guiding projections 66 in radial directions.
the molding die 60 next is closed, and resin is poured through the gate 62. In a closed state, the first ribs 12A of the primary molded article 10 are supported by the supports 61 as shown in FIG. 4. The primary molded article 10 is held at opposite sides in the width direction WD and substantially in the resin injection direction from the gate 62 with the first ribs 12A sandwiched by the supports 61 at the opposite widthwise surfaces thereof. Thus, there is no likelihood that the primary molded article 10 is displaced when the resin injected from the gate 62 collides with the facing surface 14. Further, the primary molded article 10 is reinforced by the first and second ribs 12A, 12B and there is no likelihood that the primary molded article 10 will displace due to the collision of the resin. Furthermore, the second ribs 12B are embedded in the secondary molded portion 30 after the insert molding and water cannot enter into external clearances that might otherwise exist between the second ribs 12B and the secondary molded portion 30. The molding die 60 then is opened to access the resin molded article 1 in which the primary molded article 10, the collars 40 and the flat metal plate 50 are integrally molded as inserts in the secondary molded portion 30.
The guiding projections 66 are on the distal or upper end of the positioning projections 64. Thus, an inclined collar 40 can be identified easily because such an inclined collar 40 will be at the height of the guiding projections 66 and distanced from the bottom surface of the lower die 60B, rather than at the height of the positioning projections 64. As a result, an undesirable situation where the collar 40 is deformed because the molding die is closed with the collar 40 inclined can be prevented or the risk thereof reduced. Therefore, the primary molded article 10 can be positioned without forming any engaging hole in the terminal surface 13.
The inner circumferential surface of the collar 40 can be brought into contact with the guiding surfaces 66A regardless of which inclined posture the collar 40 takes upon being fit onto the guiding projections 66. Accordingly, the collars 40 can be positioned while being located within the height range of the guiding projections 66 and, therefore, can be fit smoothly onto the positioning projections 64.
The flat metal plate 50 can be set in the molding die 60 even if the positional precision of the holes 51 of the metal flat plate 50 is poor. Further, even if the inclined posture of the collar 40 cannot be found out before the insert molding, whether the collar 40 is deformed can be easily confirmed by checking the amounts of the collar 40 exposed from the notches 52 after the insert molding.
The rib 12 increases the strength of the primary molded article 10 and ensures that the molten resin injected from the gate 62 during the insert molding prevents deformation of the primary molded article 10. Further, the supports 61 of the molding die assembly 60 support the first ribs 12A and prevent a forward displacement of the primary molded article 10 in the injection direction of the molten resin.
Parts around the first ribs 12A that were supported by the supports 61 remain as recesses on the outer surface of the resin molded article 1 after the insert molding. However, the second ribs 12B are covered by the secondary molded portion 30. Thus, problems such as water entrance through a boundary portion between the rib 12 and the secondary molded portion 30 can be reduced.
The supports 61 sandwich the first ribs 12A at opposite side surfaces. As a result, both forward and backward displacements of the primary molded article 10 in the injection direction of the molten resin can be prevented.
The invention is not limited to the above described and illustrated embodiment. For example, the following embodiments are also embraced by the technical scope of the present invention as defined by the claims.
Although the second ribs 12B are embedded in the secondary molded portion 30 in the foregoing embodiment, they may be at least partly exposed to the outside after the insert molding.
Although two supports 61 sandwich the first ribs 12A from opposite sides in the foregoing embodiment, the support 61 may be provided at one position to support the surfaces of the ribs 12A opposite to those facing the gate 62 according to the invention.
Patent Application
20080000668
