Resin-molded article fit with a metal plate

A sensor unit 10 is provided with a metal plate 20 and a resin molded article 30 is formed integral to the metal plate 20. Busbars 50 are arranged in the resin molded article 30 and include exposed end portions 52 exposed from the resin molded article 30. Connecting portions 52A are provided at the leading ends of the exposed end portions 52 and are riveted to an oil temperature sensor 41 on the metal plate 20. Opposite lateral sides of the exposed end portions 52 are partly in contact with the resin molded article 30.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a resin molded article fit with a metal plate.

2. Description of the Related Art

U.S. Pat. No. 7,488,904 andFIGS. 11-14herein disclose a resin molded article fit with a metal plate. With reference toFIG. 11, the metal plate is identified by the numeral1and the resin molded article is identified by the numeral2. Busbars3are arranged in the resin molded article2. Each busbar3includes an end portion3A exposed from the resin molded article2and an electronic component4is riveted to the exposed end portion3A of the busbar3, as shown inFIG. 12. The resin molded article2fit with the metal plate1is mounted in a transmission and transmission oil in the transmission can exert hydraulic pressure on the resin molded article2. The highly rigid metal plate1is intended to prevent the hydraulic pressure from deforming the resin molded article2.

Opposite ends of the exposed end portions3A of each busbar3are formed integral to the resin molded article2and hence are entirely in contact with the resin molded article2, as shown inFIG. 13or14, to prevent deformation. However, even if deformations of the exposed end portions3A can be prevented, stresses concentrate on parts connecting the exposed end portions3A and the electronic component4to increase contact resistance when a hydraulic pressure acts on the exposed end portions3A.

The invention was developed in view of the above situation and an object thereof is to prevent an increase of contact resistance while preventing the deformation of a busbar caused by a hydraulic pressure.

SUMMARY OF THE INVENTION

The invention relates to a resin molded article formed integrally with a metal plate. At least one busbar is arranged in the resin molded article and includes at least one exposed end portion exposed from the resin molded article. At least one connecting portion is provided near the leading end of the exposed end portion and is to be fixed to an electronic component arranged on the metal plate. Opposite lateral sides of parts of the exposed end portion are in contact with the resin molded article.

The above-described resin molded article fit with the metal plate may be used in a transmission and hydraulic pressure may act on the exposed end portion. Only parts of the exposed end portions have opposite lateral sides in contact with the resin molded article and frictional resistance between the opposite lateral sides of the exposed end portion and the resin molded article is small. As a result, the entire exposed end portion can be deformed resiliently and stresses are distributed over the entire exposed end portion without being concentrated on the connecting portion. Therefore, contact resistance will not increase and hydraulic pressure will not deform the busbar.

Opposite lateral sides of the connecting portion may be entirely in contact with the resin molded article. Thus, frictional resistance between the opposite lateral sides of the connecting portion and the resin molded article increases and movements of the connecting portion are restricted during riveting.

A connector portion may project from an outer peripheral edge of the resin molded article and at least partly accommodates an end portion of the busbar different from the exposed end portion.

At least one bulge may bulge out from the outer peripheral edge of the resin molded article in a projecting direction of the connector portion. The bulge is adjacent to the connector portion and substantially faces the exposed end portion. The exposed end portion may extend in a bulging direction of the bulge.

A dead space is formed at a position adjacent to the connector portion that projects from the outer peripheral edge of the resin molded article. However, the bulge is in the dead space facing the exposed end portion, thereby using the dead space efficiently. Further, stresses on the exposed end portion are distributed more easily since the bulge enables the exposed end portion to be lengthened.

Only one lateral side of the exposed end portions may be formed integral to the resin molded article except at the connecting portions.

The unit may comprise one or more guides and the electronic component may comprise one or more engaging guides that engage the one or more guides to guide an assembling operation of the electronic component.

A connection space may penetrate the resin molded article so that the exposed end portion is provided therein.

A part of the connection space that does not contact the lateral side of the exposed end portion may be wider than a part thereof held in contact with the lateral edge of the exposed end portion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A sensor unit in accordance with the invention is identified by the numeral10inFIGS. 1 to 5and is to be mounted on or in a device such as a transmission of an automotive vehicle and used in such a state as to be able to touch a transmission oil. As shown inFIG. 1, the sensor unit10has a metal plate20, a resin molded article30formed integral to the metal plate20and at least one electronic component. As shown inFIG. 2, the electronic component includes an oil temperature sensor41, one or more oil pressure switches42and the like.

The resin molded article30is made e.g. of synthetic resin (e.g. glass filled 6,6-nylon). Metallic busbars50are arranged in the resin molded article30. The resin molded article30includes a primary molded portion31formed integrally on a surface of the metal plate20toward the front of the plane ofFIG. 2. A secondary molded portion32is formed by insert molding and is integral to the primary molded portion31. The busbars50excluding the opposite end portions thereof are embedded in the secondary molded portion32.

Four substantially round connection holes21and three substantially round mounting recesses33are arranged alternately at intervals in a longitudinal direction in the sensor unit10. Although not shown, the surface of the metal plate20is exposed at bottoms of the mounting recesses33. The oil pressure switches42are mounted in respectively in the mounting recess33and are held in contact with the surface of the metal plate20. Two cutouts33A are formed in the surrounding wall of the mounting recess33at positions substantially facing each other. First and second terminals42A,42B of each oil pressure switch42project respectively into the cutouts33A.

Lands51of the busbars50are arranged near the cutouts33A. Each land51and the first terminal42A of the oil pressure switch42are formed with substantially coaxial through holes. The land51and the first terminal42A are riveted through these through holes. On the other hand, the second terminal42B of the oil pressure switch42is held in substantially surface contact with the metal plate20. The second terminal42B and a part of the surface of the metal plate20are formed with substantially coaxial through holes and are riveted through these through holes.

The connection holes21penetrate the metal plate20and the resin molded article30to fix the sensor unit10to a mating member (not shown) in the transmission.

A sensor mounting portion34is provided near the leftmost connection hole21of the sensor unit10. As shown inFIG. 2, the sensor mounting portion34is open laterally toward the outer peripheral edge of the resin molded article30and upwardly toward the front of the plane ofFIG. 2. The oil temperature sensor41is to be mounted into the sensor mounting portion34from the outer peripheral edge side (right side in the shown example) of the resin molded article30.

As shown inFIG. 7, the oil temperature sensor41includes a main body41A made e.g. of synthetic resin and formed by injection molding. A thermosensitive portion41B is arranged substantially vertically in the main body41A and an upper end of the thermosensitive portion41B projects up from the upper end of the main body41A. A thermistor (not shown) is embedded in the thermosensitive portion41B by filling resin. A terminal41C projects from the rear surface of the main body41A inFIG. 6, which is substantially at a leading end in a mounting direction of the oil temperature sensor41into the sensor mounting portion34. The terminal41C is to be connected electrically with the thermistor.

A seal ring43is mounted on the outer circumferential surface of the main body41A in a circumferential direction. On the other hand, a sensor insertion hole penetrates an outer wall of a transmission case (not shown) in a thickness direction. The main body41A is inserted into the sensor insertion hole and the seal ring43is held tightly between the sensor insertion hole and the main body41A to prevent leakage of the transmission oil in the transmission case to the outside.

Two opposed guiding walls35are provided on the sensor mounting portion34and an engaging projection36projects in each of the guiding walls35. As shown inFIG. 3, the engaging projections36extend laterally in projecting directions of the terminal41C. On the other hand, two engaging grooves44are formed in the main body41A of the oil temperature sensor41and are engageable with the corresponding engaging projections46, as shown inFIG. 7. Similar to the engaging projections36, the engaging grooves44extend substantially in the lateral direction. Thus, assembly of the oil temperature sensor41is guided by sliding the oil temperature sensor41between the guiding walls35and into the sensor mounting portion34while engaging the engaging projections36and the engaging grooves44. The oil temperature sensor41is held while being positioned vertically with respect to the sensor mounting portion34.

A connection space37is formed at the left side of the sensor mounting portion34, as shown inFIGS. 3 and 6, and communicates with an inner space of the sensor mounting portion34. The connection space37penetrates the resin molded article30substantially vertically and substantially orthogonal to the surface of the metal plate20. Exposed end portions52of two of the busbars50are cantilevered rightward from the left side wall of the connection space37and into the connection space37. The exposed end portions52are exposed toward the upper and lower sides through the connection space37.

The upper surface of the terminal41C is held in substantially surface contact with the lower surfaces of the exposed end portions52of the busbars50, as shown inFIG. 6, when the engaging projections36and the engaging grooves44are engaged. Connecting portions52A are formed near the leading ends of the exposed end portions52of the busbars50and fixing holes penetrate the exposed end portions52vertically. On the other hand, through holes penetrate the terminal41C and are substantially coaxial with the fixing holes of the connecting portions52A. Rivets60fix the fixing holes to electrically connect the oil temperature sensor41and the busbars50.

As shown inFIG. 8, both opposite lateral sides of the connecting portions52A of the busbars50are integral to the resin molded article30. On the other hand, only one of the opposite lateral sides of the exposed end portion52is integral to the resin molded article30along areas from the left end of each exposed end portion52to the connecting portion52A, as shown inFIG. 9or10. Specifically, the exposed end portions52are separated by a partition wall38in the resin molded article30and the lateral sides of the exposed end portion52facing the partition wall38are formed integral to the partition wall38. In other words, the opposite lateral sides of the exposed end portions52are partly in contact with the resin molded article30. A part of the connection space37not in contact with both lateral sides of the exposed end portions52is wider than a part thereof held in contact with both lateral edges of the exposed end portions52at the connecting portions52A.

According to the above-described construction, the opposite lateral sides of the exposed end portions52are only partly in contact with the resin molded article30and frictional resistance between the opposite lateral sides of the exposed end portions52and the resin molded article30is small. Therefore the entire exposed end portions52can be deformed resiliently. Hence, stresses are distributed along substantially the entire exposed end portions52and do not concentrate on the connecting portions52A. Thus, contact resistance does not increase and hydraulic pressure will not deform the busbars50. Further, frictional resistance between the opposite lateral sides of the connecting portions52A and the resin molded article30increases and movements of the connecting portions52A are restricted e.g. upon the riveting operation.

A connector portion11is provided on the left side of the outer peripheral edge of the sensor unit10and projects leftward, as shown inFIG. 2. The connector portion11projects from the resin molded article30in a direction substantially opposite to a projecting direction of the oil temperature sensor41, as shown inFIG. 4. Further, as shown inFIG. 5, the connector portion11is a receptacle that at least partly covers tab-shaped terminals53formed at ends of the five busbars50. Two of the tab-shaped terminals53are at ends of the busbars50opposite to the exposed end portions52.

A dead space normally would be formed at a position adjacent the connector portion. For example, the connector portion5enlarges the entire length of the conventional resin molded article2shown inFIG. 11and forms a dead space DS adjacent to the connector portion5. However, in this embodiment, a bulge12bulges out from the outer periphery of the sensor unit1substantially in the projecting direction of the connector portion11. The bulge12is adjacent to the connector portion11and substantially faces the exposed end portions52thereby effectively utilizing the dead space.

The bulge12enables the outer peripheral edge of the metal plate20to be extended in a bulging direction of the bulge12and the connection space37also is extended in the bulging direction of the bulge12. As a result, the exposed end portions52are extended in the bulging direction of the bulge12and the entire length of the exposed end portions52becomes longer by that much. Thus, stress acting on or along the exposed end portions52are distributed more easily and reduce stresses acting on the connecting portions52A are reduced.

The oil temperature sensor41is slid between the guiding walls35of the sensor mounting portion34of the sensor unit10from the right side while the engaging projections36engage the engaging grooves44. Thus, the oil temperature sensor41is held and positioned vertically. The terminal41C of the oil temperature sensor41and the exposed end portions52of the busbars50are held vertically and in surface contact, and the corresponding fixing holes are arranged substantially coaxially.

The rivets60are inserted through the corresponding pairs of the fixing holes of the terminal41and the exposed end portions52. The rivets60then are crimped using a crimping machine to fix the terminal41C of the oil temperature sensor41and the exposed end portions52of the busbars50for electrically connecting the oil temperature sensor41and the busbars50.

The sensor unit10then is mounted in the transmission will touch the transmission oil during use. Thus, the transmission oil will exert hydraulic pressure on the sensor unit10. At this time, the exposed end portions52can receive stress due to the direct action of the hydraulic pressure in the connection space37and via the terminal41C due to hydraulic pressure on the oil temperature sensor41. These stresses have the potential to deform the busbars50.

However, only one lateral side of the exposed end portions52is integral to the resin molded article30except at the connecting portions52A. Thus, frictional resistance between the exposed end portions52and the resin molded article30is small and the exposed end portions52are more easily and resiliently deformable from the base ends to the leading ends. Further, the exposed end portions52shown inFIG. 6are longer than the conventional exposed end portions3A shown inFIG. 12. Hence, stresses acting on the exposed end portions52are distributed more easily so that the terminal41C and the connecting portions52A can be held in contact. In this way, an increase of contact resistance in the connected parts of the busbars50and the oil temperature sensor41is prevented while the deformations of the busbars50are prevented.

As described above, one lateral side of each exposed end portion52is not in contact with the resin molded article30from the base end to the leading end except at the connecting portions52A. Thus, the exposed end portions52can be deformed resiliently from the base ends and stress acting on the connected parts of the terminal41C and the connecting portions52A is reduced. Therefore, contact resistance in the connected parts of the oil temperature sensor41will not increase and the busbars50will not deform.

Both lateral sides of the connecting portions52A are integral to the resin molded article30. Thus, the busbars50are positioned more accurately and rivet insertion errors are eliminated. Further, the connecting portions52A will not move vertically during riveting. Furthermore, lateral vibrations will not move the busbars50thereby improving reliability of the connecting portions52A.

The bulge12is in the dead space at the position adjacent to the connector portion11, thereby utilizing the dead space effectively. Further, the bulge12enables the exposed end portions52to be lengthened. Therefore, stresses acting on the connected parts of the terminal41C and the connecting portions52A are reduced further.

The invention is not limited to the above described and illustrated embodiment. For example, the following embodiments are also included in the technical scope of the present invention.

The one lateral sides of the exposed end portions52are formed integral to the resin molded article30in the ranges from the base ends to the leading ends of the exposed end portions52in the above-described embodiment. However, these lateral sides may be connected intermittently with the resin molded article30in the above ranges according to the invention.

The connecting portions52A are provided at the leading ends of the exposed end portions52in the above-described embodiment. However, the connecting portions52A may be provided at intermediate positions between the base ends and the leading ends of the exposed end portions52.

The bulge12lengthens exposed end portions52in the above-described embodiment. However, they may be lengthened by lengthening the entire length of the sensor unit10without providing the bulge12. Further, the bulge12need not necessarily be provided at the position adjacent to the connector portion11.