Busbar Unit, Electric Motor and Electrohydraulic Power Steering System Furnished With the Busbar Unit, and Method of Manufacturing the Busbar Unit

Abstract

A busbar unit for attachment to on an electric-motor armature is furnished with: busbars having terminals for supplying drive current to the armature; a plurality of connecting pins each of approximately J-shaped metal; a busbar holder retaining the busbars and the connecting pins; and a circuit board disposed on the upper side of the busbar holder, and in which a sealant injection port and an air-bleeding hole are formed.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic sectional view taken axially, illustrating one mode of embodying the present invention, with a control circuit indicated in phantom;

FIG. 2 is an exploded oblique view illustrating principal constituent elements of a stator of the present invention;

FIG. 3 is a schematic, fragmentary, enlarged sectional view taken axially, illustrating a portion of a busbar unit of the present invention, with an external jack represented in phantom;

FIG. 4 is a chart setting forth flow in the manufacture of a busbar unit of the present invention;

FIG. 5 is a schematic oblique view illustrating a circuit board going onto a sensor holder in the course of manufacturing a busbar unit of the present invention;

FIG. 6 is a schematic oblique view illustrating the sensor holder with the circuit board fixed onto it, going into a receiving niche in a busbar holder, represented fragmentarily, in the course of manufacturing a busbar unit of the present invention;

FIGS. 7 and 8 are views of the busbar unit portion in FIG. 3, but further fragmented and enlarged, representing the injection of a sealant through an injection nozzle, depicted fragmentarily, into the receiving niche in the course of manufacturing a busbar unit of the present invention;

FIG. 9 is a schematic oblique view illustrating the sensor-holder and circuit-board assembly fitted into the recess in a busbar holder in the course of manufacturing a busbar unit of the present invention, wherein the busbar holder is represented fragmentarily and the hatching indicates sealant;

FIGS. 10 and 11 are fragmentary, enlarged plan views, seen from overhead, illustrating a portion of a busbar unit in respective further embodiments of the present invention;

FIG. 12 is schematic, fragmentary, enlarged sectional view taken axially, illustrating a portion of the busbar unit in the embodiment of FIG. 11, and representing the injection of a sealant through an injection nozzle, depicted fragmentarily, into the receiving niche;

FIG. 13 is a view similar to that of FIG. 12, but illustrating a portion of a busbar unit into which a sealant is being injected in a different embodiment;

FIG. 14 is, like FIG. 3, a schematic, fragmentary, enlarged sectional view taken axially, but illustrating a portion of a busbar unit in yet a different embodiment of the present invention; and

FIG. 15 is, also like FIG. 3, a schematic, fragmentary, enlarged sectional view taken axially, but illustrating a portion of a busbar unit in still a further embodiment of the present invention, with the external jack represented in phantom.

Claims

1. A busbar unit for placement on the upper side, with respect to a predetermined orientation of a center axis in an electric motor, of the motor armature, to establish an electrical linkage for supplying drive current to the armature, the busbar unit comprising: a plurality of busbars having a plurality of terminals for electrically connecting the armature with an electric-current supply unit;a busbar holder retaining the section of the busbars that connects their plurality of terminals, the busbar holder formed by injection-molding of a non-conductive thermoplastic resin material; anda plurality of approximately linear, metal connecting pins, either ends of which are exposed from said busbar holder, with a portion of said connecting pins between either ends being located in the interior of said busbar holder.

2. The busbar unit as set forth in claim 1, wherein said plurality of connecting pins is insert-molded into said busbar holder.

3. The busbar unit as set forth in claim 1, further comprising a circuit board disposed on one side of said busbar holder and joined to each of one ends of said plurality of connecting pins.

4. The busbar unit as set forth in claim 1, further comprising a sensor connected to said circuit board, for detecting the rotational position of a rotor section of the motor.

5. The busbar unit as set forth in claim 1 wherein: each of said one ends of said connecting pins are exposed so as to protrude perpendicularly from said one side of said busbar unit; anda plurality of holes through which said one ends are respectively inserted is formed in said circuit board.

6. The busbar unit as set forth in claim 1, wherein the other ends of said plurality of connecting pins are exposed for detachably/reattachably connecting to an external connector jack.

7. The busbar unit as set forth in claim 1, wherein the other ends of said plurality of connecting pins, and a region of said busbar holder surrounding said other ends are configured so as to form a part of a connector plug for plugging into an external connector jack.

8. The busbar unit as set forth in claim 7, wherein: said busbar holder is shaped in an approximately annular form;said region of said busbar holder is formed protruding upwards along the holder outer periphery; andsaid one ends of said plurality of connecting pins are disposed radially inward of said region of said busbar holder.

9. The busbar unit as set forth in claim 8, further comprising a plurality of foot portions formed circumferentially spaced on said busbar holder, for determining the holder's axial position with respect to the armature, with one of said plurality of foot portions being disposed along the bottom side of said busbar holder where it circumferentially corresponds to said region.

10. The busbar unit as set forth in claim 1, wherein each of said plurality of connecting pins is approximately J-shaped in conformation.

11. The busbar unit as set forth in claim 1, wherein: said plurality of busbars is retained by said busbar holder in an approximately arcuate form; andsaid connecting pins are disposed circumferentially in between the respective ends of said plurality of busbars.

12. The busbar unit as set forth in claim 1, wherein: among said plurality of terminals on said busbar, terminals for connecting with the electric-current supply unit are protruded upwards with respect to the top side of said busbar holder; anda region surrounding the current-supply-unit connection terminals is configured so as to form a part of a connector plug for plugging into an external connector jack.

13. The busbar unit as set forth in claim 12 further comprising a plurality of foot portions formed circumferentially spaced on said busbar holder, for determining the holder's axial position with respect to the armature, with one of said plurality of foot portions being disposed along the bottom side of said busbar holder where it circumferentially corresponds to said region.

14. The busbar unit as set forth in claim 1, further comprising: a sealant injected in between said busbar holder and said circuit board; anda receiving portion, provided in said busbar holder on said one side thereof where said circuit board is disposed, in which said connecting pins are partially accommodated; whereinsaid circuit board abuts on said busbar holder so as to cover said receiving portion; andat least a portion of the sealant is charged into said receiving portion.

15. The busbar unit as set forth in claim 14, further comprising an injection port through which the sealant is injected, the injection port being provided in said circuit board, in said busbar holder, or in between said circuit board and said busbar holder.

16. The busbar unit as set forth in claim 15, wherein the injection port is a through-hole or a notch formed in said circuit board.

17. The busbar unit as set forth in claim 15, further comprising an aperture separate from the injection port, provided in said circuit board, in said busbar holder, or in between said circuit board and said busbar holder.

18. The busbar unit as set forth in claim 17, wherein said aperture is a through-hole or a notch formed in said circuit board.

19. The busbar unit as set forth in claim 14, further comprising an electronic part mounted on a surface of said circuit board opposing said busbar holder, whereby the electronic part is also accommodated in said receiving portion.

20. The busbar unit as set forth in claim 8, further comprising: a sealant injected in between said busbar holder and said circuit board; anda receiving portion, provided in said busbar holder on said one side thereof where said circuit board is disposed, in which said connecting pins are partially accommodated; whereinsaid circuit board abuts on said busbar holder so as to cover said receiving portion; andat least a portion of the sealant is charged into said receiving portion.

21. The busbar unit as set forth in claim 20, further comprising an electronic part mounted on a surface of said circuit board opposing said busbar holder, whereby the electronic part is also accommodated in said receiving portion.

22. A busbar unit for placement on the upper side, with respect to a predetermined orientation of a center axis in an electric motor, of the motor armature, to establish an electrical linkage for supplying drive current to the armature, the busbar unit comprising: a plurality of busbars having a plurality of terminals for electrically connecting the armature with an electric-current supply unit;a busbar holder retaining the section of the busbars that connects their plurality of terminals, the busbar holder formed by injection-molding of a non-conductive thermoplastic resin material;a circuit board disposed on one side of said busbar holder;a plurality of connecting pins inserted into the interior of said busbar holder when it is molded, so as to expose a portion of the pins from said one side of said busbar holder, said connecting pins being electrically connected to said circuit board;a sealant injected in between said busbar holder and said circuit board; anda receiving portion, provided in said busbar holder on said one side thereof where said circuit board is disposed, in which said connecting pins are partially accommodated; whereinsaid circuit board abuts on said busbar holder so as to cover said receiving portion; andat least a portion of the sealant is charged into said receiving portion.

23. The busbar unit as set forth in claim 22, further comprising an electronic part mounted on a surface of said circuit board opposing said busbar holder, whereby the electronic part is also accommodated in said receiving portion.

24. The busbar unit as set forth in claim 22, further comprising an injection port through which the sealant is injected, the injection port being provided in said circuit board, in said busbar holder, or in between said circuit board and said busbar holder.

25. The busbar unit as set forth in claim 24, further comprising an aperture separate from the injection port, provided in said circuit board, in said busbar holder, or in between said circuit board and said busbar holder.

26. The busbar unit as set forth in claim 22, further comprising: a sensor having terminals electrically connected to said circuit board and, for detecting magnetic-pole position of a rotor section of the electric motor when opposed to the outside surface of said rotor section;a sensor holder fixed to at least one of either said busbar holder or said circuit board, and having a recess, opening toward an outer-side surface of said rotor section, in which said sensor is retained; whereina portion of the sealant is charged into a space between said sensor and said circuit board.

27. The busbar unit as set forth in claim 22, wherein the sealant is applied to the side of said circuit board, being fixed to said one side of said busbar holder, opposite from the side along said busbar holder.

28. A method of manufacturing a busbar unit for placement on the upper side, with respect to a predetermined orientation of a center axis in an electric motor, of the motor armature, to establish an electrical linkage for supplying drive current to the armature, the method comprising: (a) a step of fixing a circuit board to one side of a busbar holder retaining busbars having terminals for supplying drive current to the armature; and(b) a step of injecting a sealant in between said busbar holder and said circuit board.

29. The busbar unit manufacturing method as set forth in claim 28, wherein in said step (b), said sealant is injected through an injection port provided in said circuit board, in said busbar holder, or in between said circuit board and said busbar holder.

30. The busbar unit manufacturing method as set forth in claim 29 further comprising: (c) a step of confirming, through an aperture separate from the injection port, provided in said circuit board, in said busbar holder, or in between said circuit board and said busbar holder, the amount of sealant charged.

31. An electric motor comprising: a busbar unit as set forth in claim 1;a stator section having an armature;a rotor section having a field magnet, centered on a predetermined center axis, for developing torque between said rotor section and said armature;a bearing mechanism centered on the center axis, rotatably supporting said rotor section with respect to said stator section; anda housing accommodating said stator section and said rotor section.

32. An electric motor in which a rotation control unit not immersed in fluid is isolated from a drive unit immersed in fluid, the electric motor comprising: a busbar unit as set forth in claim 22;a stator section having an armature;a rotor section having a field magnet, centered on a predetermined center axis, for developing torque between said rotor section and said armature;a bearing mechanism centered on the center axis, rotatably supporting said rotor section with respect to said stator section; anda housing accommodating said stator section and said rotor section.

33. The electric motor as set forth in claim 32, wherein said electric motor is installed in an electrohydraulic power steering system.