Control unit

A control unit includes a plurality of electronic components; and at least two metal busbars disposed along each other. Each of the at least two metal busbars establishes an electrical connection between the electronic components and includes a magnetic-material portion. The at least two metal busbars are arranged to cause the magnetic-material portion of one of the at least two metal busbars to have magnetic poles generating a magnetic force substantially in the same direction as that of the magnetic-material portion of another of the at least two metal busbars which is adjacent to the magnetic-material portion of the one of the at least two metal busbars.

BACKGROUND OF THE INVENTION

The present invention relates to a control unit.

For example in the case where a control unit for controlling a transmission for a vehicle or the like is mounted inside a transmission casing; a lubricating oil is flowing inside the transmission casing, and hence there is a possibility that a contamination (contaminants) included in the lubricating oil enters into the control unit. Accordingly, there is a possibility that such a contamination establishes an electrical connection between wires of the control unit so that a short circuit between the wires is caused and thereby the control unit does not work properly.

In order to solve such a problem, Japanese Patent Application Publication No. 2004-28189 discloses a previously proposed control unit. In this technique, by providing the coil magnet inside a control unit, the contamination is forced to stick to the coil magnet. Also in this technique, the wires are covered by a base member and a cover. Thus, the short circuit, that is caused between wires of the control unit due to the contamination, is suppressed.

SUMMARY OF THE INVENTION

However, in the case where a coil magnet is provided inside the control unit as the technique disclosed in the above patent application, a magnet force of the coil magnet becomes weaker as a distance from the coil magnet becomes longer. Accordingly, the coil magnet cannot attract the contamination in an area having a long distance from the coil magnet, and hence the short circuit that is caused between wires of the control unit due to the contamination cannot be sufficiently suppressed. If the number of coil magnet is increased as a countermeasure to this, there is another problem that the control unit cannot be designed to be small.

Moreover, in the case where the wires are covered by the base member and the cover, if the wiring of the control unit is complex, it is necessary to form the base member and the cover in complex shapes corresponding to this complex wiring and also it is necessary to secure a large space for mounting the base member or the cover between the wires. Therefore, there is a problem that the control unit cannot be designed to be small.

It is therefore an object of the present invention to provide a control unit, devised to suppress the short circuit of wires due to a contamination and also devised to design the control unit to be small.

According to one aspect of the present invention, there is provided a control unit comprising: a plurality of electronic components; and at least two metal busbars disposed along each other, wherein each of the at least two metal busbars establishes an electrical connection between the electronic components and includes a magnetic-material portion, wherein the at least two metal busbars are arranged to cause the magnetic-material portion of one of the at least two metal busbars to have magnetic poles generating a magnetic force substantially in the same direction as that of the magnetic-material portion of another of the at least two metal busbars, wherein the magnetic-material portion of the one of the at least two metal busbars is adjacent to the magnetic-material portion of the another of the at least two metal busbars.

DETAILED DESCRIPTION OF THE INVENTION

Reference will hereinafter be made to the drawings in order to facilitate a better understanding of the present invention.

At first, a structure according to a first embodiment of the present invention will be now explained with reference toFIG. 1.FIG. 1is a schematic configuration view showing a portion of a control circuit provided inside a control unit. In this embodiment, the control unit is exemplified as a unit disposed in oil within an oil pan for vehicle.

Control circuit1includes electronic components (electronic parts)2aand2b, and a plurality of metal busbars (conductive metal bars)3. Each metal busbar3electrically connects electronic component2awith electronic component2b. Electronic component2ais, for example, a controller including an electronic substrate (circuit board) and the like. Electronic component2bis, for example, a terminal portion for being connected with an external electronic component such as an oil temperature sensor. However, electronic components2aand2baccording to the first embodiment are not limited to the above-mentioned kinds of component.

Each metal busbar3is formed of magnetic material (substance), and electrically connects electronic component2awith electronic component2binside a casing of the control unit. Namely, metal busbar3is interposed between electronic component2aand electronic component2bto connect electronic component2aand electronic component2bwith each other. Each metal busbar3is magnetized, namely in magnetically polarized state. The plurality of metal busbars3are disposed in parallel with (or along) one another, and adjacent two metal busbars3have been magnetized to have substantially same magnetic property as each other. Namely, magnetic poles of one metal busbar3are arranged to generate magnetic force in the same direction as the other metal busbar3disposed in parallel with the one metal busbar3, and the one metal busbar3is magnetized so as to substantially equalize the magnetic force thereof with that of the other metal busbar3. For example, each parallel-disposed metal busbar3has been magnetized to allow one side of metal busbar3which is connected to electronic component2ato become south pole, and to allow another side of metal busbar3which is connected to electronic component2bto become north pole. In lieu thereof, the magnetic poles of metal busbar3may be constructed conversely, namely to allow one side of metal busbar3which is connected to electronic component2ato become the north pole, and to allow another side of metal busbar3which is connected to electronic component2bto become the south pole.

By virtue of the above-mentioned structure, a short circuit (circulatory shunt) between metal busbars3disposed in parallel with each other can be suppressed, even in the case where a contamination (contaminants or foreign object) gets mixed into the control unit.

Next,FIG. 2shows the contamination4sticking or clinging to metal busbar3in the case where contamination4gets mixed into or enters the control unit constructed according to this embodiment.

When contamination4gets mixed inside the control unit, and an end portion4aof contamination4comes in contact with the south pole of metal busbar3; end portion4amaking contact with the south pole of metal busbar3is made to be north pole, and another end portion4bof contamination4is made to be south pole.

Although end portion4aof contamination4which is in contact with the south pole of metal busbar3is attracted to metal busbar3by virtue of magnetic force of metal busbar3, another end portion4bof contamination4is drifting or flowing within the oil. At this time, the other metal busbar3placed next to (or near) the metal busbar3currently contacting contamination4has the same magnetic property as the metal busbar3currently contacting contamination4, and magnetic poles (respective north poles and south poles) of these two metal busbars3are aligned in the same direction. Accordingly, end portion4bhaving the magnetic polarity of south pole reacts against or repels the other metal busbar3placed next to (or near) the metal busbar3contacting (end portion4aof) contamination4.

Then, end portion4bhaving the magnetic polarity of south pole is attracted to a north-pole side of the metal busbar3contacting contamination4, by virtue of magnetic force. Then, end portion4bsticks to the metal busbar3already contacting end portion4aof contamination4. Contamination4under this state is shown by a broken line inFIG. 2. Each of the other parallel-disposed metal busbars3also can cause any contamination4mixed into the control unit to stick to the each of the other parallel-disposed metal busbars3in the similar manner as explained above, and thereby the short circuit between metal busbars3can be avoided.

In this embodiment, the above explanations are given on the precondition that the control unit is provided in oil. However, the structure according to this embodiment of the present invention is not limited to this precondition, and is also applicable to a control unit provided in outside-air ambient atmosphere.

Moreover in this embodiment, the above explanations are given on the precondition that each metal busbar3is formed in a linear shape. However, the structure according to this embodiment of the present invention is not limited to this precondition, namely is also applicable to the case where each metal busbar3is formed in a complex shape including a bending portion and the like. Even in such a case, by forming metal busbars3out of magnetic material, the short circuit which is possibly caused between metal busbars3due to contamination4can be suppressed.

Effects and benefits according to the first embodiment of the present invention will be now explained.

In the first embodiment; each metal busbar3establishing the electrical connection between electronic component2aand electronic component2bis formed of magnetic material, and metal busbars3provided in parallel with (or along) one another inside the control unit are formed to have the substantially identical magnetic property to one another. Further, metal busbars3provided along one another are disposed to line (their north and south) magnetic poles so as to generate magnetic forces of metal busbars3in the same direction. Therefore, for example, even if contamination4gets mixed into the control unit, contamination4is prevented from bridging (getting in contact with) two metal busbars3disposed in parallel with each other, so that contamination4is forced to stick to one metal busbar3. Thus, the short circuit between metal busbars3due to the entry of contamination4can be suppressed in the control unit.

By magnetizing metal busbars3, contamination4can be made to stick to one metal busbar3constituting (included in) control circuit1. Accordingly, it is unnecessary to provide a magnet or the like for attracting or sticking to contamination4inside the control unit. Thus, the control unit can be designed to be smaller, i.e., downsized.

Even when the power supply of the control unit is turned off, the state where contamination4is sticking to metal busbar3is maintained. Accordingly, the points (area) which are liable to cause the short circuit due to contamination4can be identified, and thereby the measures to make sure the control unit doesn't fail can be implemented. Namely, the point (area) of the control unit at which the short circuit is relatively easy to occur can be determined for undertaking the countermeasures thereagainst.

It is unnecessary to prepare and provide a complex shape of the casing, a sealing compound (agent) for being used when e.g., connecting the control unit with an external electronic component, and the like; in order to prevent contamination4from entering or in order to prevent the short circuiting trouble between adjacent metal busbars3from occurring. Accordingly, the control unit can be simplified and miniaturized so that a reduction in cost is achieved.

Next, a second embodiment of the present invention will be now explained with reference toFIG. 3. In this second embodiment, structures different fromFIG. 1are mainly explained. In this second embodiment, the structure of a metal busbar10is different from the first embodiment and hence will be explained at first.

Metal busbar10includes a magnetic member (magnetic-material portion)11and a conductive non-magnetic member (non-magnetic-material portion)12. An end portion of metal busbar10is non-magnetic member12, namely, one of non-magnetic members12is located at the end portion of metal busbar10. Namely, metal busbar10is formed, by alternately placing magnetic members11and non-magnetic members12on the one non-magnetic member12defined as the end portion of metal busbar10, and by electrically connecting these magnetic members11and non-magnetic members12in series with one another. In other words, metal busbar10includes both end portions formed of non-magnetic material and an intermediate portion formed by repeatedly connecting magnetic material and non-magnetic material alternately in series with each other, so that metal busbar10electrically connects electronic component2awith electronic component (e.g., terminal portion)13.

Since non-magnetic member12is provided as the end portion of metal busbar10; a portion of metal busbar10for being connected with terminal portion13of the control unit can be non-magnetic member12placed inside terminal portion13as shown by a broken line inFIG. 3, and a portion of metal busbar10for protruding from a surface of terminal portion13can be an end portion of magnetic member11, for example in the case where the control unit is connected with an external electronic component. Namely, only the non-magnetic member12corresponding to the end portion of metal busbar10can be inserted into terminal portion13to connect metal busbar10with terminal portion13. Since there may be spots remaining open to the external (clearances continuing to outside of the control unit) in the vicinity of terminal portion13of the control unit, there is a possibility that contamination4enters through this spot (clearance) into the control unit. However, by positioning the end portion of magnetic member11at the metal busbar10's portion starting to protrude from terminal portion13, contamination4can be made to stick to this end portion of magnetic member11which is strong in magnetic force. Thereby, contamination4can be more prevented from entering or moving to the inside of the control unit, and hence the short circuit between metal busbars10due to contamination4can be more prevented from occurring in the control unit. Moreover, in the case where metal busbars10are electrically connected with each other inside electronic component2a, the magnetic properties of these metal busbars10can be made to be independent of each other by providing non-magnetic member12at the end portion of each metal busbar10as explained above.

In metal busbar10, two magnetic members11are placed to sandwich non-magnetic member12between the same magnetic poles (north poles or south poles) of this two magnetic members11. Namely, the plurality of magnetic members11are electrically connected with non-magnetic members12so as to cause non-magnetic member12to be sandwiched between end portions of two magnetic members11which have the identical magnetic pole. For example, when two magnetic members11are electrically connected with each other through one non-magnetic member12, the two magnetic members11are placed so as to connect the respective north-pole sides (or respective south-pole sides) of these two magnetic members11with both (longitudinal) ends of the one non-magnetic member12. In other words, the longitudinal ends of two magnetic members11which have the identical magnetic pole face each other through non-magnetic member12.

As explained above, metal busbar10is formed by alternately placing magnetic members11and non-magnetic members12and then electrically connecting the placed magnetic members11and non-magnetic members12with each other. Accordingly, a variation of (positional) magnetic force of metal busbar10relative to a longitudinal direction of metal busbar10can be reduced, so that the short circuit which occurs due to contamination4can be suppressed.

A magnetic member (material) which has been magnetized has relatively weak magnetic force at a portion between the opposite two magnetic poles, i.e., near the center of the magnetic member. Therefore, in the case where the metal busbar is constructed by using only one magnetic member and in the case where the metal busbar is long; there is relatively high possibility that the short circuit between adjacent two metal busbars disposed along each other occurs due to a contamination near the center of the magnetic member. However in this embodiment, metal busbar10is formed by alternately placing and connecting magnetic members11and non-magnetic members12, i.e., by connecting one set of magnetic member11and non-magnetic member12with the other set of magnetic member11and non-magnetic member12. Accordingly, even in the case where the longitudinal length of metal busbar10becomes long; the positional variation of magnetic force in the longitudinal direction of metal busbar10can be made small, so that the short circuit which occurs due to contamination4can be suppressed.

In this embodiment, the example that metal busbar10includes three magnetic members11connected with one another through non-magnetic members12has been explained. However, the number of magnetic members11is not limited to three, and may be greater or smaller than three.

Effects and benefits according to the second embodiment of the present invention will be now explained.

According to the second embodiment; one metal busbar10is constituted by magnetic members11and conductive non-magnetic members12. Therefore, even in the case where the length of metal busbar10becomes long, the short circuit which occurs due to contamination4can be suppressed between adjacent two metal busbars10. Particularly in the proximity of the center of metal busbar10, the short circuit can be suppressed between the opposite magnetic poles of metal busbar10.

Even if it is necessary to design the shape of metal busbar10to be complex, e.g., a shape including a bending portion; magnetic members11and non-magnetic members12can be arranged according to this desired shape of metal busbar10, e.g., by placing non-magnetic member12at the bending portion. Moreover in this case, the lengths of magnetic members11and non-magnetic members12can be adjusted according to the desired shape of metal busbar10. Thereby, the magnetic properties of adjacent metal busbars10can be adjusted, so that the short circuit between two metal busbars10disposed along each other can be suppressed.

According to the second embodiment; the end portion of metal busbar10corresponds to non-magnetic member12. Therefore, by inserting non-magnetic member12corresponding to the end portion of metal busbar10into terminal portion13provided for being connected with an external electronic component, the metal busbar10's portion starting to protrude from terminal portion13can be the end portion of magnetic member11. Namely, an end of magnetic member11can be positioned to correspond to an inner end of terminal portion13as shown inFIG. 3. Thereby, contamination4entering and moving from the vicinity of terminal portion13into the control unit can be made to stick to the end portion of magnetic member11which has strong magnetic force. Thus, the short circuit between metal busbars10due to contamination4can be prevented from occurring inside the control unit.

Next, a third embodiment of the present invention will be now explained with reference toFIG. 4. In this third embodiment, structures different fromFIG. 1are mainly explained. In the structure according to this third embodiment, a mould portion (enclosing portion)15is provided in addition to the structure of the first embodiment.

Mould portion15is provided so as to enclose or be moulded to metal busbars10in the proximity of the longitudinal centers of metal busbars10. Namely, mould portion15encloses the whole of center portion of metal busbar10or covers a part of center portion of metal busbar10. Mould portion15is an insulating member formed of insulating material, and hence does not make an electrical connection between metal busbars10disposed in parallel with each other. Although the magnetized metal busbar10has the property of making magnetic force relatively weak near the center of metal busbar10, mould portion15is provided over an area close to the center of metal busbar(s)10in this embodiment. Accordingly, the short circuit between metal busbars10can be prevented from occurring near the center of metal busbar10due to contamination4intruding into the control unit.

Effects and benefits according to the third embodiment of the present invention will be now explained.

According to the third embodiment; since the insulating mould portion15is provided near the center of metal busbar10and between the magnetic poles of metal busbar10, the short circuit due to contamination4can be suppressed between metal busbars10disposed along each other.

This application is based on a prior Japanese Patent Application No. 2007-091028 filed on Mar. 30, 2007. The entire contents of this Japanese Patent Application are hereby incorporated by reference.