Patent Description:
To date, there has existed an electric rotating machine apparatus in which a control unit is integrated with an electric rotating machine in such a way as to be adjacent to the electric rotating machine in an axial direction of the rotation axle thereof. A stator, a rotor, and the like are incorporated in the housing of the electric rotating machine. The control unit is provided adjacent to the electric rotating machine in the axial direction thereof; the control unit has a control circuit board on which an inverter for making currents flow in stator windings and a control circuit for controlling the inverter are mounted. The electric rotating machine apparatus has a bus bar for making an electric current flow and a bus-bar holder that holds the bus bar.

There is known an electric power steering apparatus in which in order to fix a bus bar, a bus-bar holder is provided with a protruding portion and in which a through hole is provided in the bus bar and then the protruding portion is press-fitted into the through hole so that the bus bar is held by the holder. The protruding portion has a columnar portion and two or more ribs provided on the outer circumferential surface of the columnar portion in such a way as to be in parallel with the center axis of the columnar portion. The respective ribs make contact with the inner surface of the through hole in the bus bar (for example, Patent Document <NUM>).

The protruding portion of the bus-bar holder disclosed in Patent Document <NUM> is a structure for attaching the bus bar to the bus-bar holder; fixation of other components is not described in Patent Document <NUM>. A case may occur where inside a control unit, a bus-bar holder holding a bus bar is made to additionally hold other components such as a circuit board and the like. In this situation, it is required that a new protruding portion is provided in the bus-bar holder and the circuit board is provided with a through hole corresponding to the new protruding portion.

Provision of the new protruding portion enlarges the bus-bar holder. In addition, it is required that the circuit board is provided with a through hole for avoiding the protruding portion for making the bus-bar holder hold the bus bar, in addition to the through hole for making the bus-bar holder hold the circuit board. Accordingly, the area of the through holes on the control circuit board increases; thus, the mounting area of wiring leads and electronic components on the control circuit board decreases. In order to secure a necessary mounting area of the wiring leads and the electronic components, the total board area increases, eventually. As a result, the increase in the total board area becomes a contributing factor that hinders downsizing and cost saving of the electric rotating machine. Patent document <CIT> discloses an electric rotating machine comprising a bus bar and a bus-bar holder having a protruding portion penetrating a through hole of the bus bar.

Accordingly, the objective of the present disclosure is to dispense with any additional protruding portion to be provided at a time when the circuit board is assembled with the bus-bar holder holding the bus bar, to realize downsizing and cost-saving of the bus-bar holder and circuit board, and then to realize downsizing and cost-saving of the electric rotating machine apparatus.

In addition, the objective thereof is to realize downsizing and cost-saving of a power steering apparatus provided with the foregoing electric rotating machine apparatus.

An electric rotating machine apparatus according to the present invention as defined in claim <NUM> includes.

An electric power steering apparatus according to the present disclosure includes the foregoing electric rotating machine apparatus.

An electric rotating machine apparatus according to the present disclosure can dispense with any additional protruding portion to be provided at a time when the circuit board is assembled to the bus-bar holder holding the bus bar. Accordingly, it is made possible to perform downsizing and cost reduction of the bus-bar holder and the circuit board; thus, downsizing and cost reduction of the electric rotating machine apparatus can be achieved.

In addition, there can be achieved downsizing and cost reduction of an electric power steering apparatus equipped with the electric rotating machine apparatus according to the present disclosure.

Hereinafter, embodiments of the present disclosure will be explained with reference to the drawings.

In <FIG>, the circuit diagram of an electric rotating machine apparatus <NUM> represents a control unit <NUM> and an electric rotating machine <NUM>. The electric rotating machine apparatus <NUM> may be either the one in which a control circuit and a Y-connected or delta-connected three-phase brushless electric rotating machine <NUM> are integrated with each other or the one that has a function of utilizing regenerative electric power, generated by driving a load, for charging a battery. The electric rotating machine apparatus <NUM> is utilized not only in an electric power steering apparatus <NUM> but also in various uses including vehicle-wheel driving.

The control unit <NUM> includes an inverter circuit <NUM> for supplying an electric current to the electric rotating machine <NUM>, a control circuit unit <NUM> in which a CPU (Central Processing Unit) <NUM> is mounted, a power-relay switching device <NUM>, and a filter unit <NUM>. The filter unit <NUM> is provided for suppressing noise generated by the inverter circuit <NUM>.

The filter unit <NUM> is connected with a power source and a grounding terminal from a battery <NUM> mounted in a vehicle. The power source is provided to a power-source circuit <NUM> in the control circuit unit <NUM> through an ignition switch <NUM>. A sensor group <NUM> is connected with an input circuit <NUM> in the control circuit unit <NUM>. The sensor group includes, for example, a steering angle sensor that is mounted close to a steering wheel and detects a steering angle, a torque sensor for detecting steering torque, and a speed sensor for detecting a vehicle traveling speed. A signal from the power-source circuit <NUM> makes the power source travel through the filter unit <NUM> and the power-relay switching device <NUM>; then, the power source becomes a current source for the inverter circuit <NUM>. The filter unit <NUM> includes a coil 17a, an X capacitor 17b, and Y capacitors 17c and 17d. In accordance with noise generated by the electric rotating machine apparatus <NUM>, an unillustrated common mode coil may be added thereto, the coil 17a can be removed, or the number of the capacitors can be reduced.

Information items from the sensor group <NUM> are transmitted to the CPU <NUM> by way of the input circuit <NUM> of the control circuit unit <NUM>. Based on those information items, the CPU <NUM> calculates and outputs a control amount corresponding to an electric current for making the electric rotating machine <NUM> rotate. The output signal of the CPU <NUM> is transmitted to the inverter circuit <NUM> by way of a driving circuit <NUM> included in an output circuit. The driving circuit <NUM> is disposed within the control circuit unit <NUM>, because only a small electric current flows therein; physically, the driving circuit <NUM> is mounted on a control circuit board <NUM> along with the CPU <NUM>, the power-source circuit <NUM>, and the input circuit <NUM>. However, the driving circuit <NUM> can also be disposed within a power module <NUM> along with the inverter circuit <NUM>.

The inverter circuit <NUM> includes upper-arm switching devices 31U, 31V, and 31W and lower-arm switching devices 32U, 32V, and 32W for three-phase windings U, V, and W of the electric rotating machine <NUM> and electric-rotating-machine relay switching devices 34U, 34V, and 34W for connecting/disconnecting wiring leads between the windings of the electric rotating machine <NUM> and the inverter circuit <NUM>. The inverter circuit <NUM> further includes current-detection shunt resistors 33U, 33V, and 33W and smoothing capacitors 30U, 30V, and 30W. Because having the same circuit configuration for each of the windings of the respective phases, the inverter circuit <NUM> can supply electric currents independently to the windings of the respective phases.

In addition, although not illustrated, respective electric potential differences across the shunt resistors 33U, 33V, and 33W, winding-terminal voltages of the electric rotating machine <NUM>, and the like are fed back to the input circuit <NUM>. These information items are also inputted to the CPU <NUM>; the first CPU <NUM> calculates the difference between the calculated current value and a detection value and then performs feedback control so as to supply a desired current for the electric rotating machine <NUM> and to operate the electric rotating machine <NUM>.

Still moreover, the drive circuit <NUM> also outputs a drive signal for the power-relay switching device <NUM> that operates as a relay for connecting or disconnecting a power-source line between the battery <NUM> and the inverter circuit <NUM>. The power-relay switching device <NUM> can cut off current supply to the electric rotating machine <NUM> itself. The electric-rotating-machine relay switching devices 34U, 34V, and 34W are also provided in the inverter circuit <NUM> and can cut off the respective phases. In addition, a large electric current flows and hence heat is generated in the power-relay switching device <NUM>; thus, it may be allowed that the power-relay switching device <NUM> is disposed not in the control circuit board <NUM> but in the power module <NUM> in which the inverter circuit <NUM> is incorporated. The control circuit board <NUM> is a printed circuit board on one side or both sides of which electronic components are mounted.

The CPU <NUM> has an abnormality detection function of detecting an abnormality in the sensor group <NUM>, the driving circuit <NUM>, the inverter circuit <NUM>, the wirings of the electric rotating machine <NUM>, or the like. When an abnormality is detected, in order to cut off current supply, for example, only for a predetermined phase in accordance with the abnormality, the CPU <NUM> turns off the corresponding-phase upper-arm switching devices 31U, 31V, and 31W, the corresponding-phase lower-arm switching devices 32U, 32V, 32W, or the corresponding-phase electric-rotating-machine relay switching devices 34U, 34V, 34W. Furthermore, it is also made possible that in order to cut off all the electric currents, the power-relay switching device <NUM> is turned off so that the power source itself is cut off.

The electric rotating machine <NUM> is a brushless electric rotating machine in which three-phase windings are delta-connected. Because being a brushless electric rotating machine, the electric rotating machine <NUM> is provided with a rotation sensor <NUM> for detecting the rotation position of the rotor. The rotation information is also fed back to the input circuit <NUM>. It may be allowed that the electric rotating machine <NUM> is not three-phase delta-connected brushless electric rotating machine but either a Y-connected brushless electric rotating machine or an electric rotating machine having dipole-two-pair brushes. Moreover, as is the case with the winding specification of a conventional apparatus, either distributed winding or concentrated winding can be adopted.

Next, the periphery of the filter unit <NUM> will be explained. PWM (Pulse Width Modulation) control of the inverter circuit <NUM> in the control unit <NUM> generates switching noise. The filter unit <NUM> is provided in order to prevent the switching noise from being transferred from the electric rotating machine apparatus <NUM> to the outside. The coil 17a is the one for normal-mode noise and is called a "normal mode coil". In addition, although not illustrated, it may be allowed that a coil that is the one for common-mode noise and is called a "common mode coil" is added.

The X capacitor 17b is the one that is called an "across-the-line capacitor" or an "X capacitor". Each of the Y capacitors 17c and 17d is the one that is called a "line-bypass capacitor" or a "Y capacitor". The filter unit <NUM> suppresses conductive noise and radiation noise by use of these filter elements and is called an "EMI (Electromagnetic Interface) filter". In addition, the middle point 17e between the Y capacitors 17c and 17d is a body ground and is electrically connected with the vehicle body by way of part of the electric rotating machine apparatus <NUM> so as to be grounded.

<FIG> is a side cross-sectional view for explaining the physical configuration of the electric rotating machine apparatus <NUM> according to Embodiment <NUM>; the control unit <NUM> is cut at a cross section including the center axis of the electric rotating machine <NUM>. The electric rotating machine <NUM> disposed at the lower side of <FIG> and the control unit <NUM> disposed at the upper side of <FIG> are integrated with and adjacent to each other in the axial direction of the rotation axle <NUM> of the electric rotating machine <NUM>. As is the case with a conventional apparatus, the electric rotating machine <NUM> is incorporated in an electric-rotating-machine case <NUM>; in the periphery of the rotation axle <NUM>, there are arranged a rotor in which unillustrated permanent magnets in two or more pole pairs are arranged and a stator that is spaced apart from the rotor and around which windings are wound. The respective windings are wound for the three phases; the end portions of the respective phases extend toward the control unit <NUM> for the sake of connection (unillustrated).

The top portion and the outer circumference of the control unit <NUM> are covered with a housing <NUM>; on the top portion of the housing, there are arranged a power-source connector <NUM> where a relatively large power-source-system current flows and a signal connector <NUM> where a relatively small signal-system current flows. The power-source connector <NUM>, the signal connector <NUM>, and the housing <NUM> are integrally molded with one another by means of a resin material.

<FIG> is a top cross-sectional view of the electric rotating machine apparatus <NUM> according to Embodiment <NUM>; it is a drawing illustrating the control unit <NUM>, when the control unit <NUM> is cut beneath the ceiling surface of the electromagnetic shield <NUM> and is viewed from the power-source connector side. In the control unit <NUM>, a heat sink <NUM> is disposed at the middle portion thereof inside the housing <NUM>.

In the middle of the heat sink <NUM>, there is disposed a columnar portion <NUM> whose cross section is formed in the shape of a rectangular column. The control circuit board <NUM> is vertically disposed along the side surface of one of the long sides of the columnar portion <NUM> of the heat sink <NUM>. A bus bar unit <NUM> is disposed at the side surface of the other one of the long sides of the columnar portion <NUM> of the heat sink <NUM>.

The power module <NUM> is vertically disposed along the side surface of one of the short sides of the columnar portion <NUM> of the heat sink <NUM>. The power module <NUM> has a control circuit board connecting terminal at one side thereof along the short side and a bus-bar-unit connecting terminal at the other side thereof. The control circuit board connecting terminal is connected through soldering; the bus-bar-unit connecting terminal is connected through TIG (Tungsten Insert Gas) welding or the like. The power module <NUM> is provided behind the heat sink and is disposed at the position indicated by a double-dot chain line in <FIG>.

The heat sink <NUM> includes the foregoing columnar portion <NUM> and a ring-shaped base portion <NUM> fixed to one longitudinaldirection end portion of the columnar portion <NUM>. The columnar portion <NUM> of the heat sink <NUM> is disposed in the central portion of the housing <NUM> in such a way that the longitudinal direction thereof is along the axis line of the housing <NUM> of the control unit <NUM>. The base portion <NUM> of the heat sink <NUM> is supported by the electric-rotating-machine case <NUM> in such a way that the outer circumferential surface thereof is inscribed in the inner circumferential surface of the electric-rotating-machine case <NUM>. That is to say, the heat sink <NUM> is disposed in such a way that the base portion <NUM> thereof is fixed to the electric-rotating-machine case <NUM> and that the columnar portion <NUM> supported in a cantilever manner by the base portion <NUM> protrudes toward the inner space of the housing <NUM>.

An insertion hole is provided in the base portion <NUM> of the heat sink <NUM>. The respective end portions of the three-phase windings in the electric rotating machine <NUM> pass through the insertion hole and are connected with the bus bars of the bus bar unit <NUM> in the control unit <NUM> (unillustrated).

The base portion <NUM> of the heat sink <NUM> is formed in a stepped shape. The electric-rotating-machine case <NUM> is fixed to the outer circumference of the larger-diameter portion of the base portion <NUM>. The metal and cylindrical tubular electromagnetic shield <NUM> for suppressing noise emission is fixed to the outer circumference of the smaller-diameter portion of the base portion <NUM>.

The electromagnetic shield <NUM> is disposed in such a way as to cover the columnar portion <NUM> of the heat sink <NUM>, the control circuit board <NUM>, the bus bar unit <NUM>, and the power module <NUM>; part of the control circuit board <NUM> protrudes to the outside of the electromagnetic shield <NUM> through a through hole <NUM> in the top portion of the electromagnetic shield <NUM>. In <FIG>, only the control circuit board <NUM> protrudes from the through hole <NUM> in the top portion of the electromagnetic shield <NUM>. However, part of the heat sink <NUM> or part of the bus bar unit <NUM> may protrude from the through hole <NUM>.

The bus bar unit <NUM> includes a bus-bar holder <NUM> in which a bus bar <NUM> is embedded in a resin member, the smoothing capacitors 30U, 30V, and 30W, and the coil 17a. The bus bar <NUM> is connected with the respective end portions of the windings of the three phases of the electric rotating machine <NUM>, the connection terminal of the power module <NUM>, the respective terminals of the smoothing capacitors 30U, 30V, and 30W and the coil 17a, and the respective terminals of the power source and the ground extended from the power-source connector <NUM>.

The control circuit unit <NUM>, the power-relay switching device <NUM>, and the filter unit <NUM> in <FIG> are mounted on the control circuit board <NUM>. On the control circuit board <NUM>, there are mounted circuit components for controlling the inverter circuit <NUM> that supplies electric currents to the electric rotating machine <NUM>. The X capacitor 17b and the Y capacitors 17c and 17d included in the filter are arranged on a protruding portion <NUM>, of the control circuit board <NUM>, that protrudes from the through hole <NUM> in the top portion of the electromagnetic shield <NUM>. In addition, the protruding portion <NUM> of the control circuit board <NUM> is connected with respective external connection terminals, of the power source and the ground, that extend from the power-source connector <NUM>; the filter unit <NUM> prevents noise from leaking out to the outside through these connection terminals. In <FIG>, the X capacitor and the Y capacitors are arranged on the outer circumferential side of the protruding portion <NUM>; however, the X capacitor and the Y capacitors may be arranged on the inner circumferential side of the protruding portion <NUM>. In addition, in the foregoing explanation, the coil 17a is disposed on the bus bar unit <NUM>; however, the normal mode coil 17a may be disposed on the protruding portion <NUM>. Because it is not required to provide a board dedicated to the filter circuit or a circuit-supporting structure dedicated to the filter circuit, the control unit can be configured compactly and inexpensively. These components are incorporated in the housing <NUM> so as to be protected. Because being incorporated in the housing <NUM>, the components can escape from being broken; thus, the electric rotating machine apparatus <NUM> can readily be handled.

In Embodiment <NUM>, because the X capacitor 17b and the Y capacitors 17c and 17d of the filter circuit are arranged on the top portion of the control circuit board <NUM>, it is not required to provide a board dedicated to the filter circuit or a circuit-supporting structure dedicated to the filter circuit; therefore, the control unit can be configured compactly and inexpensively. In addition, effective noise countermeasures can be made by providing the filter unit <NUM> having noise-removal capability, outside the through hole <NUM> in the electromagnetic shield <NUM>. Because the X capacitor and the Y capacitors are grounded not through the heat sink <NUM> close to the power module and the paths thereof, which are noise sources, but through the electromagnetic shield <NUM>, noise can be suppressed.

Moreover, because being disposed in a concave portion inside a convex portion 40a provided in the top portion of the housing <NUM>, the protruding portion <NUM> suppresses the electric rotating machine apparatus <NUM> from being upsized. In other words, because the ceiling surface of the housing <NUM> of the control unit <NUM> in the electric rotating machine apparatus <NUM>, except for the convex portions such as the convex portion 40a, the power-source connector <NUM>, and the signal connector <NUM>, can be kept compact, the downsizing can successfully be realized.

An L-shaped grounding bus bar <NUM> is disposed along the outer circumferential side of the control circuit board <NUM> and the lower side of the ceiling surface of the electromagnetic shield <NUM>.

<FIG> is an enlarged view of a side cross section, taken along the center axis, of an electric rotating machine apparatus <NUM> according to Embodiment <NUM>. <FIG> represents the connection between the control circuit board <NUM> and the electromagnetic shield <NUM>. The grounding bus bar <NUM> is formed in an L-shaped manner; the horizontal surface thereof abuts on the inside of the top surface of the electromagnetic shield <NUM> so as to be electrically connected therewith. The vertical surface thereof abuts on a grounding strip conductor <NUM> of the control circuit board <NUM> so as to be electrically connected therewith.

A hexagonal nut <NUM> is disposed beneath the portion, of the grounding bus bar <NUM>, that makes contact with the electromagnetic shield <NUM> and is supported by a resin bus-bar holder <NUM>. A screw 60a is screwed from the upper side of the top surface of the electromagnetic shield <NUM>, so that the grounding bus bar <NUM> and the lower side of the top surface of the electromagnetic shield <NUM> are adhered to and electrically connected with each other. The bus-bar holder <NUM> disposed beneath the grounding bus bar <NUM> holds the hexagonal nut <NUM> so as to apply rotation locking thereto. The bus-bar holder <NUM> holding the hexagonal nut <NUM> is assembled into the grounding bus bar <NUM> through press-fitting or the like.

From the top surface, the electromagnetic shield <NUM>, the grounding bus bar <NUM>, and the hexagonal nut <NUM> are assembled in that order; then, from the topmost position, the screw 60a is fastened. Assembling in the foregoing manner prevents any obstructive structure from protruding to the space above the screw 60a when the electromagnetic shield <NUM> and the grounding bus bar <NUM> are electrically connected with each other. Because it is not required to secure the distance between the electromagnetic shield <NUM> of the control unit <NUM> and the housing <NUM>, this configuration contributes to downsizing of the control unit <NUM> in the axial direction.

The vertical surface of the grounding bus bar <NUM> is electrically connected with the grounding strip conductor <NUM> of the control circuit board <NUM>. The grounding strip conductor <NUM> is included in the filter unit <NUM>, along with the X capacitor 17b, and the Y capacitors 17c and 17d arranged on the control circuit board. A screw 60b fastens the surface, facing the control circuit board <NUM>, of the grounding bus bar <NUM> from the outer circumferential side. The screw 60b fixes the vertical portion of the bus-bar holder <NUM>, the vertical portion of the grounding bus bar <NUM>, and the control circuit board <NUM> to a screw-fastening foundation <NUM> of the heat sink <NUM>. Due to the fastening by the screw 60b, the grounding bus bar <NUM> and the grounding strip conductor <NUM> of the filter unit <NUM> are electrically connected with each other. Because the grounding strip conductor <NUM> is included in the filter unit <NUM>, high-reliability and low-cost connection can be performed.

The screw 60b is electrically connected with the heat sink <NUM> through screw fastening. However, because each of the bus-bar holder <NUM> and the heat sink <NUM> side of the control circuit board <NUM> is insulated, neither the electromagnetic shield <NUM> nor the grounding strip conductor <NUM> of the control circuit board <NUM> is electrically connected with the screw 60b and the heat sink <NUM>. Because the X capacitor 17b and the Y capacitors 17b and 17c of the filter circuit are arranged on the top portion of the control circuit board <NUM>, it is not required to provide a board dedicated to the filter circuit or a circuit-supporting structure dedicated to the filter circuit. Accordingly, the control unit can be configured compactly and inexpensively. Moreover, because the X capacitor and the Y capacitors are grounded not through the heat sink <NUM> close to the power module and the paths thereof, which are noise sources, but through the electromagnetic shield <NUM>, noise can be suppressed.

There is adopted a structure in which fastening is performed by the screw 60b from the outer circumferential side of the center axis of the electric rotating machine <NUM>; the vertical surface of the grounding bus bar <NUM> is disposed at the outer circumferential side of the control circuit board <NUM>. As a result, the constituent portion for connecting the electromagnetic shield <NUM> with the grounding bus bar <NUM> is prevented from protruding to the upper surface of the heat sink <NUM> and wasting the space; thus, this method can contribute to downsizing of the control unit <NUM>.

<FIG> is a top view of the electromagnetic shield <NUM> in the electric rotating machine apparatus <NUM> according to Embodiment <NUM>. In the top surface of the electromagnetic shield <NUM>, there are provided the through hole <NUM> for making the control circuit board <NUM> protrude and a screw insertion hole <NUM> for making the screw 60b pass therethrough. Although not illustrated, a hole for positioning at a time of assembly may be provided. Moreover, it may be allowed that the through hole <NUM> is enlarged so that part of the top portion of the heat sink <NUM> or the bus bar unit <NUM> protrudes from the electromagnetic shield <NUM>.

Next, there will be explained the case where a grounding bus bar <NUM> and a control circuit board <NUM> are assembled into the bus-bar holder <NUM> through a method according to Comparative Example. <FIG> is a perspective view of the bus-bar holder <NUM> according to Comparative Example. <FIG> is the perspective view of the bus-bar holder <NUM>, when viewed in a direction in which an abutting surface X thereof that abuts on the grounding bus bar <NUM> is seen. In the bus-bar holder <NUM>, there are provided a first holder protruding portion <NUM>, a second holder protruding portion <NUM>, a third holder protruding portion <NUM>, and a fourth holder protruding portion <NUM>, and a holder through hole <NUM> for screw fastening, and a hexagonal nut containing portion <NUM>.

<FIG> is the abutting surface X of the bus-bar holder <NUM> according to Comparative Example, when viewed from the front side. The first holder protruding portion <NUM> and the second holder protruding portion <NUM> are utilized for assembling the bus-bar holder <NUM> with the grounding bus bar <NUM>. The first holder protruding portion <NUM> and the second holder protruding portion <NUM> have a first holder columnar portion 6101a and a second holder columnar portion 6102a, respectively; the lengths thereof are identical to each other. The length of the columnar portion signifies the overall length of the columnar portion that extends from the base thereof toward the front end thereof.

In addition, the first holder protruding portion <NUM> and the second holder protruding portion <NUM> have respective two or more ribs each having the same length and the same outer diameter, provided on the respective outer circumferential surfaces of the first holder columnar portion 6101a and the second holder columnar portion 6102a. The length of the rib signifies the overall length of the rib that extends from the base of the columnar portion toward the front end thereof. The first holder protruding portion <NUM> has four first holder ribs 6101b provided spaced evenly apart from one another. The second holder protruding portion <NUM> has two second holder ribs 6102b in the horizontal direction.

The third holder protruding portion <NUM> and the fourth holder protruding portion <NUM> are utilized for assembling the bus-bar holder <NUM> with the control circuit board <NUM>. The third holder protruding portion <NUM> and the fourth holder protruding portion <NUM> have a third holder columnar portion 6103a and a fourth holder columnar portion 6104a, respectively; the lengths thereof are identical to each other. The third holder protruding portion <NUM> and the fourth holder protruding portion <NUM> have respective two or more ribs each having the same length and the same outer diameter, provided on the respective outer circumferential surfaces of the third holder columnar portion 6103a and the fourth holder columnar portion 6104a. The third holder protruding portion <NUM> has four third holder ribs 6103b provided spaced evenly apart from one another in the horizontal and vertical directions. The fourth holder protruding portion <NUM> has two fourth holder ribs 6104b in the horizontal direction.

The columnar portion and the rib of each of the third holder protruding portion <NUM> and the fourth holder protruding portion <NUM> have respective lengths larger than respective lengths of the columnar portion and the rib of each of the first holder protruding portion <NUM> and the second holder protruding portion <NUM>. A first holder concave portion <NUM>, a second holder concave portion <NUM>, a third holder concave portion <NUM>, and a fourth holder concave portion <NUM> are provided in the respective peripheries, on the abutting surface X that abuts on the grounding bus bar, of the first through fourth protruding portions. In this example, it is assumed that the respective outer diameters of the columnar portions of the first through fourth protruding portions are identical to one another, that the respective outer diameters of the ribs of the first through fourth protruding portions are identical to one another, and that the respective outer diameters of the concave portions of the first through fourth protruding portions are identical to one another; however, it is only necessary that those respective outer diameters are appropriate for press-fitting into the corresponding through holes of the grounding bus bar; if such is the case, it may be allowed that those respective outer diameters are either identical to one another or different from one another.

<FIG> is a perspective view of the grounding bus bar <NUM> according to Comparative Example. <FIG> is the perspective view of the grounding bus bar <NUM>, when viewed in a direction in which an abutting surface Y1 thereof that abuts on the control circuit board <NUM> is seen. The grounding bus bar <NUM> is L-shaped. In the abutting surface Y1, of the grounding bus bar <NUM>, that abuts on the control circuit board <NUM>, there are provided a first bus-bar through hole <NUM> into which the first holder protruding portion <NUM> of the bus-bar holder <NUM> is inserted, a second bus-bar through hole <NUM> into which the second holder protruding portion <NUM> is inserted, a third bus-bar through hole <NUM> into which the third holder protruding portion <NUM> is inserted, a fourth bus-bar through hole <NUM> into which the fourth holder protruding portion <NUM> is inserted, and a fifth bus-bar through hole <NUM> into which a screw is inserted. In the surface, of the grounding bus bar <NUM>, that abuts on the electromagnetic shield <NUM>, there is provided a sixth bus-bar through hole <NUM> into which the screw 60a is inserted and is screwed into the hexagonal nut <NUM>.

The first bus-bar through hole <NUM> has a diameter suitable for press-fitting the first holder ribs 6101b of the first holder protruding portion <NUM> thereinto; the second bus-bar through hole <NUM> has a diameter suitable for press-fitting the second holder ribs 6102b of the second holder protruding portion <NUM> thereinto. The third bus-bar through hole <NUM> has a diameter larger than the outer diameter of the third holder ribs 6103b so as not to make contact with the third holder rib 6103b of the third holder protruding portion <NUM>; the fourth bus-bar through hole <NUM> has a diameter larger than the outer diameter of the fourth holder ribs 6104b so as not to make contact with the fourth holder rib 6104b of the fourth holder protruding portion <NUM>. In addition, the diameter of the fifth bus-bar through hole <NUM> is set to be larger than that of the holder through hole <NUM> for screw fastening, in order to avoid conduction with the screw 60b.

<FIG> is a front view of the abutting surface Y1 of a bus bar unit <NUM> according to Comparative Example, when viewed from the front side. The bus bar unit <NUM> is an assembly product obtained by assembling the grounding bus bar <NUM> to the bus-bar holder <NUM>. <FIG> is a perspective view of the bus bar unit <NUM>, when viewed in a direction in which the abutting surface Y1 thereof that abuts on the control circuit board <NUM> is seen. Scrapings of the first holder rib 6101b, produced when the first holder protruding portion <NUM> is press-fitted into the first bus-bar through hole <NUM>, are contained in the first holder concave portion <NUM> provided around the root of the first holder protruding portion <NUM>. The configuration of the second holder protruding portion <NUM> is the same as that of the first holder protruding portion <NUM>; scrapings of the second holder rib 6102b are contained in the second holder concave portion <NUM> provided around the root of the second holder protruding portion <NUM>. The third bus-bar through hole <NUM> has an outer diameter larger than that of the third holder ribs 6103b so as not to make contact with the third holder rib 6103b; the fourth bus-bar through hole <NUM> has an outer diameter larger than that of the fourth holder ribs 6104b so as not to make contact with the fourth holder rib 6104b.

<FIG> is a perspective view of the control circuit board <NUM>, when viewed in a direction in which an abutting surface Y2 thereof that abuts on the grounding bus bar <NUM> is seen. In the control circuit board <NUM>, there are provided a grounding strip conductor <NUM> formed of copper foil, a first circuit board through hole <NUM> of the control circuit board <NUM>, corresponding to the first holder protruding portion <NUM>, a second circuit board through hole <NUM> of the control circuit board <NUM>, corresponding to the second holder protruding portion <NUM>, a third circuit board through hole <NUM> of the control circuit board <NUM>, corresponding to the third holder protruding portion <NUM>, a fourth circuit board through hole <NUM> of the control circuit board <NUM>, corresponding to the fourth holder protruding portion <NUM>, and a screw-insertion fifth circuit board through hole <NUM> of the control circuit board <NUM>.

<FIG> is a second perspective view of the control circuit board <NUM> assembled to the bus bar unit <NUM>, when viewed from a heat sink <NUM> side (the heat sink <NUM> is unillustrated). The first circuit board through hole <NUM> of the control circuit board <NUM> has an inner diameter larger than the outer diameter of the first holder ribs 6101b of the first holder protruding portion <NUM>; the second circuit board through hole <NUM> of the control circuit board <NUM> has an inner diameter larger than the outer diameter of the second holder ribs 6102b of the second holder protruding portion <NUM>. As a result, the first circuit board through hole <NUM> and the second circuit board through hole <NUM> do not make contact with the first holder rib 6101b and the second holder rib 6102b, respectively. The third holder protruding portion <NUM> and the fourth holder protruding portion <NUM> are press-fitted into the third circuit board through hole <NUM> and the fourth circuit board through hole <NUM>, respectively, of the control circuit board <NUM>. The respective front ends of the first holder protruding portion <NUM> through the fourth holder protruding portion <NUM> protrude to the heat sink <NUM> side of the control circuit board <NUM>. Although not illustrated here, at the respective receipt portions of the heat sink <NUM>, there are provided avoiding holes for avoiding protruding portions, because it is required to avoid the first holder protruding portion <NUM> through the fourth holder protruding portion <NUM> that protrude from the control circuit board <NUM> to the heat sink <NUM> side.

As described above, the method according to Comparative Example requires that when the control circuit board <NUM> is assembled to the bus-bar holder <NUM> holding the bus bar unit <NUM>, there are respectively provided the first holder protruding portion <NUM> and the second holder protruding portion <NUM> for assembling the grounding bus bar <NUM> and the third holder protruding portion <NUM> and the fourth holder protruding portion <NUM> for assembling the control circuit board <NUM>. Accordingly, it is required that respective through holes or avoiding holes are provided in the grounding bus bar <NUM>, the control circuit board <NUM>, and the heat sink <NUM>. Accordingly, the additional installation of the protruding portions upsizes the bus-bar holder <NUM>. In addition, the additional installation of the through holes in the control circuit board <NUM> reduces the area where the connection lines and the components of the control circuit board can be arranged; thus, it is required to enlarge the control circuit board. Moreover, because it is required to additionally provide the avoiding holes in the heat sink <NUM>, the degree of flexibility in the shape of the heat sink <NUM> is deteriorated. As a result, upsizing of and a cost increase in the electric rotating machine apparatus <NUM> is caused, and eventually, upsizing of and a cost increase in the electric power steering apparatus <NUM> equipped with the electric rotating machine apparatus <NUM> is caused.

There will be explained assembly of the grounding bus bar <NUM> and the control circuit board <NUM> to the bus-bar holder <NUM> according to Embodiment <NUM>. <FIG> is a front view of the electric rotating machine apparatus <NUM> according to Embodiment <NUM>. <FIG> is a front view of the control circuit board <NUM> at a time when the housing <NUM> of the control unit and the electromagnetic shield <NUM> are removed. In this description, the components unnecessary for the explanation will not be illustrated. The grounding bus bar <NUM> and the bus-bar holder <NUM> for connecting the control circuit board <NUM> with the electromagnetic shield <NUM> are arranged close to the center line of the control circuit board <NUM> and are fixed to the heat sink <NUM> by the screw 60b.

<FIG> is a perspective view of the bus-bar holder <NUM> according to Embodiment <NUM>, when viewed in a direction in which an abutting surface P thereof that abuts on the grounding bus bar is seen. <FIG> is a front view of the bus-bar holder <NUM> at a time when the abutting surface P thereof faces the front. <FIG> is a cross-sectional view of the bus-bar holder <NUM> in <FIG>, taken along the XVI cross section.

The bus-bar holder <NUM> is provided with a first protruding portion <NUM>, a second protruding portion <NUM>, a seventh through hole <NUM> for screw fastening, and a hexagonal nut containing portion <NUM>. The first protruding portion <NUM> is provided with a columnar portion 611a and two or more ribs on the outer circumferential surface of the columnar portion 611a. The first protruding portion <NUM> is provided with three pieces each of a first rib 611c and a second rib 611b whose diameters are different from each other and whose lengths are different from each other. The length of the rib signifies the overall length of the rib that extends from the base of the columnar portion toward the front end thereof.

In the present embodiment, one type of the ribs, the diameter and length of which are larger than those of the other type thereof will be referred to as the first rib 611c; the other type will be referred to as the second rib 611b. The first rib 611c and the second rib 611b are utilized for press-fitting into the control circuit board <NUM> and the grounding bus bar <NUM>, respectively.

A first concave portion <NUM> whose outside is enclosed in a circle is provided around the root of the first protruding portion <NUM> on the abutting surface P, of the bus-bar holder <NUM>, that abuts on the grounding bus bar <NUM>. The second protruding portion <NUM> is in the shape of a prism whose cross section is a horizontally extended rhombus. A second concave portion <NUM> enclosing the rhombus-shaped second protruding portion <NUM> is provided around the root of the second protruding portion <NUM> on the abutting surface P that abuts on the grounding bus bar <NUM>.

<FIG> is a perspective view of the grounding bus bar <NUM>, when viewed in a direction in which an abutting surface Q1 thereof that abuts on the control circuit board <NUM> is seen. <FIG> is a front view of the grounding bus bar <NUM> utilized in Embodiment <NUM>, when the abutting surface Q1 thereof faces the front side.

The grounding bus bar <NUM> is L-shaped; in the abutting surface Q1 thereof that abuts on the control circuit board, there are provided
a second through hole <NUM> into which the first protruding portion <NUM> of the bus-bar holder <NUM> is inserted, a fourth through hole <NUM> into which the second protruding portion <NUM> is inserted, and a sixth through hole <NUM> into which a screw is inserted. In the surface, of the grounding bus bar <NUM>, that abuts on the electromagnetic shield, there is provided an eighth through hole <NUM> into which the screw 60a is inserted and is screwed into the hexagonal nut <NUM>.

The second through hole <NUM> has a circular portion 381a having a diameter corresponding to press-fitting of the second rib 611b of the first protruding portion <NUM> and two or more cut-out portions 381b provided for avoiding the first ribs 611c. Accordingly, it is made possible to perform press-fitting of the bus-bar holder <NUM> and the grounding bus bar <NUM>, without providing any effect to the shape of the first rib 611c. The fourth through hole <NUM> is a cut-out hole. The cut-out hole saves the materials for the components and facilitates assembly of the grounding bus bar <NUM> to the bus-bar holder <NUM>. In addition, the diameter of the sixth through hole <NUM> is set to be larger than that of the screw-fastening seventh through hole <NUM> in the bus-bar holder <NUM>, in order to avoid conduction with the screw 60b. In addition, in Embodiment <NUM>, the fourth through hole <NUM> of the bus bar is in the shape of a cut-out hole; however, the fourth through hole <NUM> may be in the shape of a circular hole. The machining of a circularhole shape is easy, and in order to restrict the travel of the second protruding portion <NUM>, it is desirable that the fourth through hole <NUM> is in the shape of not a cut-out hole but a through hole without a cutout.

<FIG> is a front view illustrating a bus bar unit <NUM> according to Embodiment <NUM>, when the grounding bus bar <NUM> is assembled to the bus-bar holder <NUM>. <FIG> is a view of the bus bar unit <NUM>, when the bus-bar holder <NUM> and the abutting surface Q1, of the grounding bus bar <NUM>, that abuts on the control circuit board <NUM> face the front. <FIG> is a cross-sectional view of the bus bar unit <NUM>, taken along the XX cross section in <FIG>. In some cases, when the first protruding portion <NUM> is press-fitted into the second through hole <NUM>, scrapings of part of the second rib 611b that is elastically deformed remain on the abutting surface P of the bus-bar holder <NUM>. When the scrapings adhere to the abutting surface P, of the bus-bar holder <NUM>, that abuts on the grounding bus bar <NUM>, the scrapings of the first rib 611c raise the grounding bus bar <NUM>. In order to prevent the above phenomenon, there is provided the first concave portion <NUM> whose outer circumference is circular in shape. The scrapings of the rib are contained in the first concave portion <NUM>, so that the grounding bus bar <NUM> can be suppressed from being raised. In addition, because the second protruding portion <NUM> is a resin mold, a rounded part is produced in the root portion thereof. In some cases, the grounding bus bar <NUM> collides with this rounded part and hence is raised from the abutting surface P. In order to prevent the phenomenon, the second concave portion <NUM> is provided around the root of the second protruding portion <NUM>. Because the second protruding portion <NUM> is not press-fitted into the fourth through hole <NUM> of the grounding bus bar <NUM>, part of the second concave portion <NUM> may not be enclosed by the inner wall included in the abutting surface P.

<FIG> is a perspective view of the bus-bar holder <NUM> according to Embodiment <NUM>, when viewed in a direction in which an abutting surface Q2 thereof that abuts on the grounding bus bar is seen. In the control circuit board <NUM>, there are provided the grounding strip conductor <NUM> formed of copper foil, a first through hole <NUM> corresponding to the first protruding portion <NUM>, a third through hole <NUM> corresponding to the second protruding portion <NUM>, and a fifth through hole <NUM> into which the screw 60b is inserted.

<FIG> is a front view of the control circuit board <NUM>, when the control circuit board <NUM> is assembled to the bus bar unit <NUM> according to Embodiment <NUM>. <FIG> is a cross-sectional view of the principal part and the periphery thereof, taken along the XXIII cross section in <FIG>.

When press-fitted into the first through hole <NUM> of the control circuit board <NUM>, the first rib 611c makes contact with the inner circumference portion of the first through hole <NUM>. In some cases, when the first rib 611c is press-fitted into the first through hole <NUM>, scrapings of part of the first rib 611c that is elastically deformed remain on the control circuit board <NUM> at the grounding bus bar <NUM> side. When the scrapings adhere to the abutting surface Q1 between the control circuit board <NUM> and the grounding bus bar <NUM>, the scrapings of the first rib 611c raise the grounding bus bar <NUM> from the control circuit board <NUM>. In that case, the conduction between the grounding strip conductor <NUM> of the control circuit board <NUM> and the grounding bus bar <NUM> is impeded. In order to prevent the phenomenon, the cut-out portion 381b provided in the second through hole <NUM> of the grounding bus bar <NUM> has a shape for avoiding the first rib 611c, and the scrapings are contained in the cut-out portion 381b and the first concave portion <NUM> of the bus-bar holder <NUM>; thus, the grounding bus bar <NUM> can be prevented from being raised.

<FIG> is a cross-sectional view of the principal part and the periphery thereof, taken along the XXIV cross section in <FIG>. In a receipt portion <NUM> of the heat sink <NUM>, there are provided an avoiding hole <NUM> for avoiding the first protruding portion <NUM>, an avoiding hole 343b for avoiding the second protruding portion <NUM>, and a screw fastening hole 343c. The first protruding portion <NUM> and the second protruding portion <NUM> are assembled to the avoiding hole 343a and the avoiding hole 343b, respectively, so as to be contained therein.

In Comparative Example illustrated in <FIG>, the bus-bar holder <NUM> requires the four protruding portions, i.e., the first holder protruding portion <NUM>, the second holder protruding portion <NUM>, the third holder protruding portion <NUM>, and the fourth holder protruding portion <NUM>. In contrast, in Embodiment <NUM>, as illustrated in <FIG>, the grounding bus bar <NUM> and the control circuit board <NUM> can be fixed to each other by use of the two protruding portions, i.e., the first protruding portion <NUM> and the second protruding portion <NUM>. Therefore, it may be allowed that the respective numbers of the through holes in the control circuit board <NUM> and the grounding bus bar <NUM> and the number of the avoiding holes in the heat sink <NUM> are only two. Accordingly, because the respective complexities, volumes, and assembling man-hours of the components can be reduced, downsizing and cost saving can be promoted. The downsizing of each of the components results in weight saving. Moreover, the occupation area of the through holes on the control circuit board decreases; thus, this method can contribute to downsizing of the control circuit board and further to downsizing of the control unit. Therefore, it is made possible to promote downsizing of the electric rotating machine apparatus <NUM> described in Embodiment <NUM> and a power steering apparatus provided with the electric rotating machine apparatus <NUM>; thus, this configuration can contribute to weight saving and cost reduction therefor.

There has been described the case where the bus-bar holder <NUM> according to Embodiment <NUM> illustrated in <FIG> has two protruding portions, i.e., the first protruding portion <NUM> and the second protruding portion <NUM>. However, it is made also possible that the grounding bus bar <NUM> and the control circuit board <NUM> are assembled to the bus-bar holder <NUM> by use of only the first protruding portion <NUM>, omitting the second protruding portion <NUM>. That method makes it possible to omit the second protruding portion <NUM>, the third through hole <NUM> of the control circuit board, and the fourth through hole <NUM> of the grounding bus bar. As a result, it is made possible to further promote downsizing of the electric rotating machine apparatus <NUM> and a power steering apparatus provided with the electric rotating machine apparatus <NUM>; thus, this configuration can contribute also to weight saving and cost reduction therefor.

There has been explained the example in which as illustrated in <FIG>, the first protruding portion <NUM> is provided with three pieces each of the first rib 611c and the second rib 611b whose diameters are different from each other and whose lengths are different from each other. It is not required that each of the respective numbers of the first ribs 611c and the second ribs 611b is three; it is only necessary that each of the respective numbers is plural. This is because it is only necessary that the grounding bus bar <NUM> and the control circuit board <NUM> can be press-fitted into and fixed to the bus-bar holder <NUM>.

It is desirable that more than three pieces each of the first rib 611c and the second rib 611b are provided. This is because when more than three pieces each of them are provided, fixation through press-fitting can more stably be performed and hence centering through press-fitting can securely be performed.

In addition, it is desirable that two or more ribs are provided spaced evenly apart from one another around the columnar portion 611a of the first protruding portion <NUM>. This is because when the fixation through press-fitting can further stably be performed and hence the centering through press-fitting can more securely be performed.

It may be allowed that the length of the first rib 611c is set to be the same or larger than the sum of the thickness of the grounding bus bar <NUM> and the thickness of the control circuit board <NUM>, that the length of the second rib 611b is set to be the same as or smaller than the thickness of the grounding bus bar <NUM>, and the diameter of the second rib 611b is set to be larger than the diameter of the first rib 611c. In that case, the diameter of the first through hole <NUM> in the control circuit board <NUM> and the diameter of the first rib 611c are set in such a way that interference-fitting is established therebetween, and the diameter of the second through hole <NUM> of the grounding bus bar <NUM> and the diameter of the second rib 611b are set in such a way that interference-fitting is established therebetween. As a result, the grounding bus bar <NUM> and the control circuit board <NUM> can be press-fitted into the bus-bar holder <NUM>, even without providing the cut-out portion 381b in the second through hole <NUM> of the grounding bus bar <NUM>. Because it is not required to provide the cut-out portion 381b in the second through hole <NUM> of the grounding bus bar <NUM>, this method can contribute to cost reduction.

In addition, there has been explained the example in which the respective diameters of the first rib 611c and the second rib 611b are different from each other; however, it may be allowed that the respective diameters thereof are identical to each other. In that case, the respective diameters of the second through hole <NUM> in the grounding bus bar <NUM>, the diameter of the first rib 611c, and the second rib 611b are set in such a way that loose interference-fittings are established therebetween, and the respective diameters of the second through hole <NUM> in the grounding bus bar <NUM> and the diameter of the first through hole <NUM> of the control circuit board <NUM> are set in such a way that tight interference-fitting is established therebetween, so that the grounding bus bar <NUM> and the control circuit board <NUM> can be press-fitted into the bus-bar holder <NUM>, even without providing the cut-out portion 381b in the second through hole <NUM> of the grounding bus bar <NUM>. Because it is not required to provide the cut-out portion 381b in the second through hole <NUM> of the grounding bus bar <NUM>, this method can contribute to cost reduction.

In Embodiment <NUM>, there has been explained the case where the grounding bus bar <NUM> is fixed to the bus-bar holder <NUM>. However, the application of a bus bar is not limited to the grounding application. The technology of fixation to the bus-bar holder <NUM>, explained in Embodiment <NUM>, can be applied also to the bus bars for other applications, such as a power-source bus bar and a bus bar for transferring an electric-rotating-machine driving current. In addition, in this situation, it may be allowed that the strip conductor, of the control circuit board <NUM>, that is pressed against and conductively connected with the bus bar is not a wiring strip conductor for grounding but a power-source strip conductor at the high-voltage side, a strip conductor for an electric-rotating-machine driving current, or the like.

In Embodiment <NUM>, there has been explained the case where the control circuit board <NUM> is fixed to the bus-bar holder <NUM>. However, the board to be fixed to the bus-bar holder <NUM> is not limited to the control circuit board <NUM>. The technology of fixation to the bus-bar holder <NUM>, explained in Embodiment <NUM>, can be applied also to circuit boards other than a control circuit board, such as a circuit board utilized for electric-rotating-machine driving wiring and a circuit board for transferring a rotation sensor signal.

In Embodiment <NUM>, there has been explained the case where the second protruding portion <NUM> is in the shape of a prism whose cross section is a horizontally extended rhombus in <FIG>. In contrast to the first protruding portion <NUM> in which around the columnar portion 611a, two or more ribs are provided spaced evenly apart from one another, the second protruding portion <NUM> is rhombus-shaped; therefore, even in the case where the relative position among the bus-bar holder <NUM>, the grounding bus bar <NUM>, and the control circuit board <NUM> is mistakenly turned by <NUM>°, press-fitting can be prevented by setting the dimensions in such a way that insertion is impossible. By making the cross section of the second protruding portion <NUM> rhombus-shaped and by contriving the respective shapes, such as a rhombus, which is a shape the same as that of the second protruding portion <NUM>, and an ellipse, of the fourth through hole <NUM> of the grounding bus bar <NUM> and the third through hole <NUM> of the control circuit board <NUM>, press-fitting can be prevented even in the case where the second protruding portion <NUM> is mistakenly turned by <NUM>°.

In Embodiment <NUM>, there has been explained the case where the second protruding portion <NUM> is provided. By providing the second protruding portion <NUM> in addition to the first protruding portion <NUM>, there is provided a function of preventing the relative position among the bus-bar holder <NUM>, the grounding bus bar <NUM>, and the control circuit board <NUM> from rotating. Positioning is performed by means of the first protruding portion <NUM> and the second protruding portion <NUM> before final fixation is made by use of the screw 60b, so that the assembly efficiency is raised; thus, this configuration contributes to cost reduction. Moreover, it can also be prevented that after the grounding bus bar <NUM> and the control circuit board <NUM> are press-fitted into the bus-bar holder <NUM>, relative rotation among the components causes the ribs to be scraped and hence press-fitting fixation power is deteriorated. In addition, it can be expected that the positioning by use of the first protruding portion <NUM> and the second protruding portion <NUM> raises the assembly accuracy of the product.

In Embodiment <NUM>, there is describes the configuration in which the grounding bus bar <NUM> and the control circuit board <NUM> are assembled to the bus-bar holder <NUM> and then the screw 60a fixes them to the heat sink <NUM>. By means of the first protruding portion <NUM> of the bus-bar holder <NUM>, the grounding bus bar <NUM> and the control circuit board <NUM> are assembled through press-fitting; from the screw-fastening seventh through hole <NUM> of the bus-bar holder <NUM>, the screw strongly fastens the components through the sixth through hole <NUM> of the grounding bus bar <NUM> and the fifth through hole <NUM> of the control circuit board <NUM>. This configuration makes it possible to perform high-strength fixation of the components of the electric rotating machine apparatus <NUM> in a compact, simple, and accurate manner. While the heat sink <NUM> realizes efficient cooling of the control circuit board <NUM>, the abutting surface Q2 where the grounding strip conductor <NUM> of the control circuit board <NUM> and the grounding bus bar <NUM> abut on each other secures electric conduction and junction with high-physical strength can be secured; thus, this configuration is significant.

In Embodiment <NUM>, there has been explained the case where the second protruding portion <NUM> is provided. By providing the second protruding portion <NUM> in addition to the first protruding portion <NUM>, there is provided a function of accurately determining the relative position among the bus-bar holder <NUM>, the grounding bus bar <NUM>, and the control circuit board <NUM>. Moreover, the screw-fastening seventh through hole <NUM> is provided between the first protruding portion <NUM> and the second protruding portion <NUM>; the sixth through hole <NUM> is provided between the second through hole <NUM> and the fourth through hole <NUM> of the grounding bus bar <NUM>; the fifth through hole <NUM> is provided between the first through hole <NUM> and the third through hole <NUM> of the control circuit board <NUM>. Then, from the screw-fastening seventh through hole <NUM>, the screw 60b is fastened into the screw fastening hole 343c thorough the fourth through hole <NUM> and the fifth through hole <NUM>. This configuration makes it possible that the bus-bar holder <NUM>, the grounding bus bar <NUM>, and the control circuit board <NUM>, which are positioned by the first protruding portion <NUM> and the second protruding portion <NUM>, are directly fixed to the heat sink <NUM>. Because the screw can be fastened in the through hole between the first protruding portion <NUM> and the second protruding portion <NUM>, it is prevented that stress caused by fastening the screw produces distortion and hence the relative position among the components is displaced, and it is made possible to fix the components at the accurate positions; thus, this configuration is significant.

In Embodiment <NUM>, the electromagnetic shield <NUM> for enclosing the control unit <NUM> is provided; the control circuit board <NUM> and the grounding bus bar <NUM> assembled into the control unit <NUM> are fixed to each other by the bus-bar holder <NUM>; the grounding bus bar <NUM> makes contact with the electromagnetic shield <NUM>. The configuration like this makes it possible that the control circuit board <NUM> is compactly fixed to the grounding bus bar <NUM> by the bus-bar holder <NUM> and its contact with the grounding bus bar <NUM> is secured. Accordingly, because compact and efficient fixation can be performed, this configuration can contribute to the downsizing, weight saving, and cost reduction of the electric rotating machine apparatus <NUM>. Moreover, this configuration can contribute to the downsizing, weight saving, and cost reduction of the electric power steering apparatus <NUM> utilizing the electric rotating machine apparatus <NUM>.

In Embodiment <NUM>, as illustrated in <FIG>, the control circuit board <NUM> has the grounding strip conductor <NUM> on the abutting surface Q1 that makes contact with the grounding bus bar <NUM>; the grounding strip conductor <NUM> is pressed against the grounding bus bar <NUM> so as to be electrically connected therewith. Then, the grounding bus bar <NUM> makes contact with the electromagnetic shield <NUM> so as to be electrically connected therewith. As a result, because the grounding strip conductor <NUM> of the control circuit board <NUM> and the electromagnetic shield <NUM> are electrically connected with each other, the small-size bus-bar holder <NUM> makes it possible that noise is shielded by the effective electromagnetic shield.

In Embodiment <NUM>, as illustrated in <FIG>, the grounding bus bar <NUM> is formed in an L-shaped manner; the horizontal surface thereof abuts on the inside of the ceiling portion of the electromagnetic shield <NUM> so as to be electrically connected therewith. The vertical surface thereof abuts on the grounding strip conductor <NUM> of the control circuit board <NUM> so as to be electrically connected therewith. This configuration makes it possible that when the electromagnetic shield <NUM> and the grounding bus bar <NUM> are electrically connected with each other, the electromagnetic shield <NUM> around the control unit <NUM> is efficiently and compactly provided; thus, this configuration contributes to axial-direction downsizing of the control unit <NUM>.

In Embodiment <NUM>, as illustrated in <FIG> and <FIG>, the protruding portion <NUM> of the control circuit board <NUM> protrudes to the outside of the electromagnetic shield through the through hole <NUM> in the upper portion of the electromagnetic shield. Because the external connection terminal is provided in the protruding portion <NUM> of the control circuit board <NUM>, it is made possible to perform compact external connection, while noise is prevented from propagating to the outside and external noise is prevented from invading inside.

In Embodiment <NUM>, the first protruding portion <NUM> and the second protruding portion <NUM> of the bus-bar holder <NUM> are arranged in a row along the rotation axle <NUM> of the electric rotating machine <NUM>. Moreover, the seventh through hole <NUM> for screw fastening is provided between the first protruding portion <NUM> and the second protruding portion <NUM>. In contrast, the bus-bar holder <NUM> described in Embodiment <NUM> is different from the bus-bar holder <NUM> according to Embodiment <NUM> in that the first protruding portion <NUM> and the second protruding portion <NUM> are arranged in a row along the rotation direction of the rotation axle <NUM> of the electric rotating machine <NUM>. Moreover, the seventh through hole <NUM> for screw fastening is provided between the first protruding portion <NUM> and the second protruding portion <NUM>; the seventh through hole <NUM>, the first protruding portion <NUM>, and the second protruding portion <NUM> are aligned along the rotation direction of the rotation axle <NUM>. In the case where in Embodiment <NUM>, there exists a component corresponding to that in Embodiment <NUM>, the foregoing component is designated by the same reference character.

<FIG> is a front view of the electric rotating machine apparatus <NUM> according to Embodiment <NUM>. <FIG> is a front view of the control circuit board <NUM> at a time when the housing <NUM> of the control unit and the electromagnetic shield <NUM> are removed. In this description, the components unnecessary for the explanation will not be illustrated. The grounding bus bar <NUM> and the bus-bar holder <NUM> for connecting the control circuit board <NUM> with the electromagnetic shield <NUM> are arranged across the center line of the control circuit board <NUM> and are fixed to each other by the screw 60b.

In Embodiment <NUM>, the screw-fastening seventh through hole <NUM> of the bus-bar holder <NUM> is disposed below the hexagonal nut containing portion <NUM>; in contrast, in Embodiment <NUM>, the screw-fastening seventh through hole <NUM> of the bus-bar holder <NUM> is disposed in the transverse direction of the hexagonal nut containing portion <NUM>. When as described above, the respective positions of the screw-fastening seventh through hole <NUM> and the hexagonal nut containing portion <NUM> are arranged in a row in the rotation direction of the rotation axle <NUM> of the electric rotating machine <NUM>, the dimension of the bus bar unit <NUM> in the axial direction of the rotation axle <NUM> of the electric rotating machine <NUM> can be reduced. Accordingly, the degree of flexibility in designing the electric rotating machine apparatus <NUM> increases and hence collision with other components can readily be avoided. As a result, this configuration can contribute to downsizing and cost reduction of the electric rotating machine apparatus <NUM>.

<FIG> is a perspective view of the bus-bar holder <NUM> according to Embodiment <NUM>, when viewed in a direction in which an abutting surface P thereof that abuts on the grounding bus bar is seen. <FIG> is a front view of the bus-bar holder <NUM> at a time when the abutting surface P thereof faces the front side.

The bus-bar holder <NUM> is provided with the first protruding portion <NUM>, the second protruding portion <NUM>, the screw-fastening seventh through hole <NUM>, and the hexagonal nut containing portion <NUM>. The first protruding portion <NUM> has the columnar portion 611a and two or more ribs provided on the outer circumferential surface of the columnar portion 611a. The first protruding portion <NUM> is provided with three pieces each of the first rib 611c and the second rib 611b whose diameters are different from each other and whose lengths are different from each other. In the present embodiment, one type of the ribs, the diameter and length of which are longer than those of the other type thereof will be referred to as the first rib 611c; the other type will be referred to as the second rib 611b. The first rib 611c and the second rib 611b are utilized for press-fitting into the control circuit board <NUM> and the grounding bus bar <NUM>, respectively.

The first concave portion <NUM> whose outside is enclosed in a circle is provided around the first protruding portion <NUM> on the abutting surface, of the bus-bar holder <NUM>, that abuts on the grounding bus bar <NUM>. The second protruding portion <NUM> is in the shape of a rhombus that is extended in the vertical direction in each of <FIG>. The second concave portion <NUM> enclosing the rhombus-shaped second protruding portion is provided around the second protruding portion <NUM> on the abutting surface that abuts on the grounding bus bar <NUM>.

<FIG> is a perspective view of the grounding bus bar <NUM>, when viewed in a direction in which an abutting surface Q1 thereof that abuts on the control circuit board <NUM> is seen. <FIG> is a front view of the grounding bus bar <NUM> according to Embodiment <NUM>, when the abutting surface Q1 thereof faces the front side.

The grounding bus bar <NUM> is L-shaped. In the abutting surface, of the grounding bus bar <NUM>, that abuts on the control circuit board <NUM>, there are provided the second through hole <NUM> into which the first protruding portion <NUM> of the bus-bar holder <NUM> is inserted, and the fourth through hole <NUM> into which the second protruding portion <NUM> is inserted, and the sixth through hole <NUM> into which a screw is inserted. In the surface, of the grounding bus bar <NUM>, that abuts on the electromagnetic shield <NUM>, there is provided the eighth through hole <NUM> into which the screw 60a is inserted and is screwed into the hexagonal nut <NUM>.

The second through hole <NUM> has a circular portion 381a having a diameter corresponding to press-fitting of the second rib 611b of the first protruding portion <NUM> and two or more cut-out portions 381b provided for avoiding the second ribs. The fourth through hole <NUM> is a cut-out hole. In addition, the diameter of the sixth through hole <NUM> is set to be larger than that of the screw-fastening seventh through hole <NUM> in the bus-bar holder <NUM>, in order to avoid conduction with the screw. In addition, in Embodiment <NUM>, the fourth through hole <NUM> of the grounding bus bar <NUM> is in the shape of a cut-out hole; however, the fourth through hole <NUM> may be in the shape of a circular hole.

<FIG> is a perspective view of the bus bar unit <NUM> according to Embodiment <NUM>, when the bus-bar holder <NUM> and the grounding bus bar <NUM> are assembled to each other. <FIG> is a perspective view of the bus bar unit <NUM>, when viewed in a direction in which the abutting surface Q1 thereof that abuts on the control circuit board <NUM> is seen. <FIG> is a front view of the bus bar unit <NUM> according to according to Embodiment <NUM>, when the abutting surface Q1 faces the front side.

In some cases, when the first protruding portion <NUM> is press-fitted into the second through hole <NUM>, scrapings of part of the second rib 611b that is elastically deformed remain on the abutting surface of the bus-bar holder <NUM>. When the scrapings of the second rib 611b adhere to the abutting surface P, of the bus-bar holder <NUM>, that abuts on the grounding bus bar <NUM>, some of the scraped ribs raise the grounding bus bar <NUM> from the bus-bar holder <NUM>. In order to prevent the above phenomenon, the first concave portion <NUM> whose outer circumference is circular in shape is provided in the bus-bar holder <NUM>. Some of the scraped ribs are contained in the first concave portion <NUM>, so that the grounding bus bar <NUM> can be suppressed from being raised.

In addition, because the second protruding portion <NUM> is a resin mold, a rounded part is produced in the root portion thereof. Due to this phenomenon, the grounding bus bar <NUM> may be raised from the abutting surface. In order to prevent the phenomenon, the second concave portion <NUM> is provided around the second protruding portion <NUM>. Because the second protruding portion <NUM> of the bus-bar holder <NUM> is not press-fitted into the grounding bus bar <NUM>, part of the concave portion may not be enclosed by the inner wall.

<FIG> is a first perspective view of the control circuit board <NUM> according to Embodiment <NUM>. <FIG> is a perspective view of the control circuit board <NUM>, when viewed in a direction in which the abutting surface Q2 thereof that abuts on the grounding bus bar is seen. In the control circuit board <NUM>, there are provided the grounding strip conductor <NUM> formed of copper foil, the first through hole <NUM> corresponding to the first protruding portion, the third through hole <NUM> corresponding to the second protruding portion, and the fifth through hole <NUM> into which the screw is inserted.

<FIG> is a second perspective view of the control circuit board <NUM> according to Embodiment <NUM>, when viewed from the heat sink side, with the bus-bar holder <NUM> assembled to the control circuit board <NUM>. As is the case with Embodiment <NUM>, when press-fitted into the first through hole <NUM>, the first rib 611c makes contact with the inner circumference portion of the first through hole <NUM> of the control circuit board <NUM>. In some cases, when the first rib 611c is press-fitted into the first through hole <NUM>, scrapings of part of the first rib 611c that is elastically deformed remain on the control circuit board <NUM> at the grounding bus bar <NUM> side. When the scrapings of the ribs adhere to the abutting surface Q2, of the control circuit board <NUM>, that abuts on the grounding bus bar <NUM>, the scrapings of the ribs raise the grounding bus bar <NUM> from the control circuit board <NUM>. In that case, the conduction between the grounding strip conductor <NUM> of the control circuit board <NUM> and the grounding bus bar <NUM> is impeded. In order to prevent the phenomenon, the cut-out portion 381b provided in the second through hole <NUM> of the grounding bus bar <NUM> has a shape for avoiding the second rib 611b, and the scrapings of the ribs are contained in the cut-out portion 381b and the first concave portion <NUM> of the bus-bar holder <NUM>; thus, the grounding bus bar <NUM> can be prevented from being raised.

Although not illustrated, in the receipt portion <NUM> of the heat sink <NUM>, there are provided the avoiding hole 343a for avoiding the first protruding portion <NUM>, the avoiding hole 343b for avoiding the second protruding portion <NUM>, and the screw fastening hole 343c. The first protruding portion <NUM> and the second protruding portion <NUM> are assembled to the avoiding hole 343a and the avoiding hole 343b, respectively, so as to be contained therein.

The effect explained in Embodiment <NUM> can be realized also in the electric rotating machine apparatus <NUM> described in Embodiment <NUM>. Moreover, in Embodiment <NUM>, the first protruding portion <NUM> of the bus-bar holder <NUM>, the screw-fastening seventh through hole <NUM>, and the second protruding portion <NUM> are arranged in a row in the rotation direction of the rotation axle <NUM> of the electric rotating machine <NUM>; thus, the dimension of the bus bar unit <NUM> in the axial direction of the rotation axle <NUM> of the electric rotating machine <NUM> can be reduced. As a result, this configuration can contribute to further downsizing of the electric rotating machine apparatus <NUM>.

<FIG> is a configuration diagram of the electric power steering apparatus <NUM> according to Embodiment <NUM>. There will be explained an example in which the electric rotating machine apparatus <NUM> is applied to the electric power steering apparatus <NUM> to be mounted in a vehicle.

<FIG> illustrates an example of a rack-type electric power steering apparatus <NUM>. When a driver makes the steering mechanism of a vehicle generate steering torque by means of a steering wheel <NUM>, a torque sensor <NUM> detects the steering torque and then outputs it to the electric rotating machine apparatus <NUM>. In addition, a speed sensor <NUM> detects the traveling speed of the vehicle and then outputs it to the electric rotating machine apparatus <NUM>. Based on the inputs from the torque sensor <NUM> and the speed sensor <NUM>, the electric rotating machine apparatus <NUM> generates auxiliary torque for supplementing the steering torque and then supplies it to the steering mechanism of front wheels <NUM> of the vehicle. The torque sensor <NUM> and the speed sensor <NUM> are included in the sensor group <NUM> in <FIG>. It may be allowed that the electric rotating machine apparatus <NUM> generates auxiliary torque based on inputs other than the inputs from the torque sensor <NUM> and the speed sensor <NUM>.

Downsizing of the electric rotating machine apparatus <NUM> to be applied to the electric power steering apparatus <NUM> raises the mountability for the vehicle. In addition, downsizing of the electric rotating machine apparatus <NUM> results in downsizing of the electric power steering apparatus <NUM>, contributes to weight saving of the electric power steering apparatus <NUM>, and also results in improvement of gasoline mileage of a vehicle. The cost reduction of the electric rotating machine apparatus <NUM> also results in cost reduction of the whole electric power steering apparatus <NUM>.

Claim 1:
An electric rotating machine apparatus (<NUM>) comprising:
an electric rotating machine (<NUM>) having a rotation axle (<NUM>);
a circuit board (<NUM>) that is disposed at one axial-direction side of the rotation axle (<NUM>) with respect to the electric rotating machine (<NUM>) and has a first through hole (<NUM>);
a bus bar (<NUM>) that has a second through hole (<NUM>) and is provided in such a way that one surface thereof makes contact with one surface of the circuit board (<NUM>); and
a bus-bar holder (<NUM>) that is provided in contact with the other surface of the bus bar (<NUM>) and has a protruding portion (<NUM>) that penetrates the first through hole (<NUM>) and the second through hole (<NUM>),
wherein the protruding portion (<NUM>) has
a columnar portion (611a),
two or more first ribs (611c) that are provided on an outer circumferential surface of the columnar portion (611a) in such a way as to be parallel with a center axis of the columnar portion (611a) and in such a way as to be spaced apart from one another, and
two or more second ribs (611b) that are provided on the outer circumferential surface of the columnar portion (611a) in such a way as to be parallel with the center axis of the columnar portion (611a) and in such a way as to be spaced apart from one another, and
wherein the first ribs (611c) abut on an inner circumferential surface of the first through hole (<NUM>) in the circuit board (<NUM>) and the second ribs (611b) abut on an inner circumferential surface of the second through hole (<NUM>) in the bus bar (<NUM>).