JP2008290614A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device having usability secured by a simple structure and reduced in the number of parts. <P>SOLUTION: In this column assisting electric power steering device, a motor mounting part 17 on which an electric motor 5 is mounted and a unit mounting part 20 on which a control unit 19 for drivingly controlling the electric motor 5 are arranged parallel to each other in a reduction gear box 4. The control unit 19 comprises a control board 19A, a power board 19B, and a module part 19C. The power board 19B and the control board 19B are placed on the unit mounting part 20 in this order at a predetermined interval. The electrical connection part of the module part 19C is so formed in a three layer as to be positioned between the control board 19A and the power board 19B. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention provides a column assist type electric motor comprising a steering column having a steering shaft to which a steering torque is transmitted, and an electric motor for transmitting a steering assist force to the steering shaft via a speed reduction mechanism in a speed reduction gear box. The present invention relates to a power steering device.

  In this type of electric power steering apparatus, a relatively large current (about 30 A to 120 A) is applied to the electric motor that generates auxiliary steering force, and the electric motor is driven for the purpose of reducing power loss and noise. It is desired to integrate the control unit to the electric motor or the reduction gear box. At the same time, for the purpose of reducing the number of components, it is desired to integrate a torque sensor for detecting steering torque and a control unit. That is, it is desired to have an electromechanical integrated configuration in which the control unit is integrated with an electric motor or a reduction gear box.

However, in the case of mechanical and electrical integration, the number of development man-hours tends to increase because there are more restrictions on development than when the control unit is made as a single box.
As a conventional electric power steering apparatus, for example, a circuit board of a motor control circuit is built in a gear housing of the electric power steering apparatus, and a drive circuit element of the motor control circuit is fixed to a heat sink mounted on the circuit board. Has a structure in which is fixed in direct contact with the gear housing (see, for example, Patent Document 1).
JP 2005-86855 A

  However, in the conventional example described in Patent Document 1, all of the electric parts such as a control circuit, a motor drive circuit, a relay, a capacitor, and a coil are mounted on the circuit board of the motor control circuit, and thus generates a lot of heat. The drive circuit element of the motor drive circuit must be fixed to the heat sink to dissipate heat to the gear housing, and a heat sink for heat dissipation is required, resulting in an unsolved problem that the number of parts increases.

  In order to solve this unsolved problem, a control module equipped with a control circuit such as a microcomputer, a power module equipped with a switching element of a motor drive circuit, etc., an L equipped with a connector, a relay, and a noise countermeasure component The first and second planes orthogonal to each other at an angle of, for example, 90 degrees are formed in the reduction gear box, and the power module is directly disposed on the first plane. The frame module is arranged on the second plane, the control module is arranged at a position facing the second plane of the frame module, and the power module and the control module are electrically connected by the frame module. It has been.

  In this case, the power module that generates a large amount of heat is mounted on a reduction gear box that has a large heat capacity and a large surface area, so that heat generated in the power module can be efficiently transferred to the reduction gear box without providing a separate heat sink. However, the frame module that electrically connects the control module and the power module becomes a large L-shape, resulting in an unsolved problem that the number of parts increases and the size increases.

  On the other hand, connectors, relays, and noise countermeasure components whose component size and shape change depending on the magnitude of steering assist torque (= motor current) required by the vehicle are mounted on the frame module, and the power module and control module are installed via this frame module. Therefore, there is an unsolved problem that versatility cannot be ensured because the structure of the entire control unit must be redesigned depending on the magnitude of the motor current.

  Further, when the size of the worm wheel constituting the speed reduction mechanism is changed depending on the magnitude of the steering assist torque required by the vehicle, for example, the position where the control module and the torque sensor are connected, and the position where the control module and the power module are connected. In addition, a relative change occurs, and in this case as well, it is necessary to redesign the structure of the entire control unit, and there is an unsolved problem that versatility cannot be ensured.

Furthermore, when the L-shaped frame module is fixed to the two planes of the reduction gear box, the structure of the frame module becomes complicated because a stress relaxation structure is required at the mating portion of the two planes of the frame module depending on the manufacturing accuracy. There are also unsolved issues.
Furthermore, since the frame module is made of a synthetic resin material, a metal collar or a female screw is required for the fixing portion, and there are unsolved problems that the number of parts is large and the cost is increased.

  Therefore, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and can ensure versatility with a simple configuration and can reduce the number of components. The purpose is to provide.

  In order to achieve the above object, an electric power steering apparatus according to a first aspect of the present invention includes a steering column having a steering shaft to which steering torque is transmitted, and a steering assist to the steering shaft via a reduction mechanism in a reduction gear box. A column assist type electric power steering apparatus having an electric motor for transmitting force, wherein a motor mounting portion for mounting the electric motor and a control unit for driving and controlling the electric motor are mounted on the reduction gear box. A control unit mounting portion is provided in parallel, and the control unit includes at least a control board on which a processing device for calculating a command value is mounted, a power board on which the switching element for the electric motor is mounted, a relay, a noise countermeasure component, etc. The control unit is composed of module parts mounted with mounted parts. The power board and the control board are stacked in that order at a predetermined interval on the attachment part, and the module part has a three-layer structure so that the electrical connection part of the module component is located between the control board and the power board. It is characterized by that.

According to a second aspect of the present invention, there is provided the electric power steering apparatus according to the first aspect of the present invention, wherein an electrical connection between the control board, the power board, and the module component includes a connection terminal for the power board and the module component on the control board. It is characterized by being performed by soldering.
Furthermore, the electric power steering apparatus according to a third aspect is the invention according to the first or second aspect, wherein the control board and the power board are arranged in parallel to each other on the unit mounting portion so as to be within one projection plane region. The module component is characterized in that an electrical connection portion to the control board is disposed between the control board and the power board, and the mounted component is disposed outside the projection plane region.

Furthermore, in the electric power steering apparatus according to claim 4, in the invention according to any one of claims 1 to 3, a storage portion for storing the mounting component of the module component is formed in the reduction gear box. It is characterized by that.
Still further, according to a fifth aspect of the present invention, there is provided the electric power steering apparatus according to any one of the first to fourth aspects, wherein the module component includes a pair of attachment portions attached to the reduction gear box and the pair of attachment portions. It is characterized by having a bus bar composed of a connecting portion that connects between them.

  According to a sixth aspect of the present invention, in the electric power steering device according to any one of the first to fifth aspects, the reduction gear box includes a torque sensor that detects a steering torque transmitted to the steering shaft. The torque sensor external connection terminal is directly connected to the control board, and the relative position of the control board and the module component changes due to the shape change of the speed reduction mechanism built in the reduction gear box. The shape of the electrical connection portion of the module component is changed in accordance with the change of the above.

  According to the present invention, the control unit is composed of a control board, a power board and a module component, and among these, the power board and the control board are stacked in that order at a predetermined interval on the unit mounting portion of the reduction gear box, Since the electrical connection part of the module parts is a three-layer structure so that it is located between the control board and the power board, when changing the shape of the unit mounting part by changing the size of the reduction gear unit, etc., the control board and the module parts Can be dealt with by changing the shape of the electrical connection portion that connects the control board and the module component, and the versatility can be improved.

Also, the control board, the power board, and the module parts are all electrically connected by soldering via the control board, and the control board, the power board, and the module parts are soldered only on one surface. Thus, the assembly process can be simplified.
Furthermore, by consolidating a group of parts whose shapes and sizes change due to the motor current size and vehicle layout restrictions as module parts, even if the number of applicable models of electric power steering devices increases, the design change location of the control unit can be changed. By limiting to module parts and using other control boards, power boards, etc., it is possible to reduce the cost including development man-hours.

  Furthermore, the control board and the power board are arranged in parallel so as to be within one projection plane region, and the module component has an electrical connection to the control board arranged between the control board and the power board. By disposing the mounted component outside the projection plane area, the distance between the control board and the power board can be minimized, and the thickness of the control unit in the column axis direction can be suppressed. can get.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a perspective view of a state in which an electric motor and a control unit are mounted on a reduction gear box, and FIG. 3 is a longitudinal section showing an enlarged part of the reduction gear box. 4 is an exploded perspective view, FIG. 5 is a perspective view showing the electric motor, FIG. 6 is a front view showing the bus bar structure of the electric motor, FIG. 7 is a perspective view seen from the front side of the reduction gear box, FIG. Is a perspective view seen from the back side of the reduction gear box, FIG. 9 is an exploded perspective view of the control unit, FIG. 10 is a perspective view seen from the side opposite to FIG. 9 of the module parts, and FIG. FIG. 12 is a schematic diagram showing a cross-sectional view of a state in which the control unit is mounted on the reduction gear box, and FIG.

  In FIG. 1, reference numeral 1 denotes a column-type electric power steering device. A reduction gear box 4 is connected to a steering column 3 that rotatably houses a steering shaft 2 connected to a steering wheel (not shown). The reduction gear box 4 is provided with an electric motor 5 composed of a motor with a brush whose axial direction extends in a direction perpendicular to the axial direction of the steering column 3.

  Here, the steering column 3 has a double tube structure of an inner tube 3a and an outer tube 3b that secures a predetermined collapse stroke by absorbing impact energy at the time of collapsing at a connecting portion with the reduction gear box 4. The outer tube 3 b and the reduction gear box 4 of the steering column 3 are attached to the vehicle body side by an upper mounting bracket 6 and a lower mounting bracket 7.

  The lower mounting bracket 7 is formed by a mounting plate portion 7a attached to a vehicle body side member (not shown) and a pair of support plate portions 7b extending in parallel with a predetermined distance on the lower surface of the mounting plate portion 7a. ing. And the front-end | tip of the support plate part 7b is connected with the support part 4b integrally formed in the cover 4a arrange | positioned at the lower end side of the reduction gear box 4, ie, the vehicle body front side, via the pivot 7c so that rotation is possible.

The upper mounting bracket 6 includes a mounting plate portion 6a attached to a vehicle body side member (not shown), a rectangular frame-shaped support portion 6b integrally formed with the mounting plate portion 6a, and the rectangular frame-shaped support portion. And a tilt mechanism 6c that supports the outer tube 3b of the steering column 3 formed in 6b.
Here, the mounting plate portion 6a is composed of a pair of left and right capsules 6d attached to a vehicle body side member (not shown), and a sliding plate portion 6f fixed to these capsules 6d by resin injection 6e. By applying an impact force that moves the steering column 3 forward of the vehicle body, the sliding plate portion 6f slides forward of the vehicle body relative to the capsule 6d, and the resin injection 6e is sheared, and the shear load is the collapse start load. It is comprised so that it may become.

Further, by rotating the tilt lever 6g of the tilt mechanism 6c and releasing the support state, the tilt position of the steering column 3 can be adjusted up and down around the pivot 7c of the lower mounting bracket 7.
Further, as shown in FIG. 3, the steering shaft 2 includes an input shaft 2a whose right end is connected to a steering wheel (not shown), and a torsion bar connected to the left end of the input shaft 2a via a torsion bar 2b. And an output shaft 2c covering 2b.

  Furthermore, as shown in FIGS. 3, 4, 7 and 8, the reduction gear box 4 is made of a material having high thermal conductivity such as aluminum, aluminum alloy, magnesium and magnesium alloy, for example. It is formed by die casting. The reduction gear box 4 has a worm storage portion 12 for storing a worm 11 connected to the output shaft of the electric motor 5, and a worm 11 having a central axis orthogonal to the central axis below the worm storage portion 12. A worm wheel storage portion 14 for storing a worm wheel 13 that meshes with the worm wheel, a torque sensor storage portion 16 for storing a torque sensor 15 that is integrally and coaxially connected to the rear side of the worm wheel storage portion 14, and a worm storage portion. 12, a motor mounting portion 17 for attaching the electric motor 5 formed on the open end surface, a column mounting portion 18 for fitting the front end portion of the steering column 3 formed on the rear end surface of the torque sensor storage portion 16, and a worm storage portion. 12 and the central axis of the worm wheel storage part 14 and the torque sensor storage part 16 across the worm wheel storage part 14 And a control unit mounting section 20 for mounting the control unit 19 which is formed in a plane perpendicular to the.

The reduction gear box 4 is fixed to the steering column 3 in a state where the steering column 3 is fitted on the column mounting portion 18 and the end surface of the steering column 3 is in contact with the end surface of the torque sensor storage portion 16.
Here, as shown in FIG. 3, the torque sensor 15 magnetically detects the torsional state between the input shaft 2a and the output shaft 2c of the steering shaft 2 and transmits the steering torque transmitted to the steering shaft to a pair of detection coils. The external connection terminals 15c and 15d are configured to be detected by 15a and 15b and project outwardly in parallel to the direction perpendicular to the central axis of the steering column 3 at the start and end of winding of the pair of detection coils 15a and 15b, respectively. 15e and 15f are connected, and the protruding portions of the external connection terminals 15c to 15f are bent at the central portion in parallel with the central axis of the steering column 3 to form an L shape.

  Further, as shown in FIG. 5, the electric motor 5 is incorporated in a position close to and opposed to the control unit 19 mounted on the control unit mounting portion 20 at a position close to the mounting flange 5 b mounted on one of the reduction gear boxes 4. The connecting terminals 5c and 5d as motor side connecting portions formed integrally with the bus bars 5i and 5j, which will be described later, are distributed to the brush to be attached to the mounting flange 5b at an inclination angle of, for example, 45 ° with respect to the axial direction of the electric motor 5. It is inclined and extended from the end face toward the front. The distal ends of the connection terminals 5c and 5d are formed in an arc shape, and a long hole 5e through which a fixing screw is inserted is formed on the distal end side.

Here, as shown in FIG. 6, each of the connection terminals 5c and 5d is disposed insulated from each other in a synthetic resin brush support 5f having an armature insertion hole in the center of the bottom, and two sets of brushes. The arc-shaped bus bars 5i and 5j individually connected to 5g and 5h are integrally formed at opposite ends.
The electric motor 5 has its mounting flange 5b connected to the motor mounting portion 17 of the reduction gear box 4 and its output shaft splined or serrated to the worm shaft 11a to which the worm 11 is mounted, and the connection terminals 5c and 5d are connected. It is attached to the rear of the vehicle.

  Further, the control unit mounting portion 20 formed in the reduction gear box 4 is provided on the upper side of the worm storage portion 12 and the lower worm wheel storage portion 14 as is apparent with reference to FIGS. A rectangular flat mounting surface 20a having a long side in the axial direction of the worm storage portion 12 formed over the straddle, and a side edge of the flat mounting surface 20a opposite to the torque sensor storage portion 16 is drilled. And a module part storage unit 20b for storing module parts to be described later.

  As shown in FIG. 8, a side wall 20c is formed on the side edge of the flat mounting surface 20a on the torque sensor housing 16 side, and a power described later in cooperation with the side wall 20c on the left end side of the side wall 20c. A positioning portion 20d for positioning the substrate 19B is formed. Further, support pieces 20e for supporting a control board 19A (described later) are formed inside both end portions of the side wall 20c, and a module component 19C (described later) is supported on the left corner and the center in the left-right direction opposite to the side wall. A support piece 20f is formed. Further, a connector support piece 20g that protrudes to the left from the front and rear end portions of the left end edge of the flat mounting surface 20a and supports a connector 19E described later is formed.

As shown in FIGS. 4 and 9, the control unit 19 includes a control board 19A, a power board 19B, a module component 19C, a motor terminal block 19D, a connector 19E, and a cover 19F.
The control board 19A calculates a steering assist current command value based on a torque detection value from the torque sensor 15 or a vehicle speed detection value from a vehicle speed sensor (not shown), and this steering assist current command value and the motor current output to the electric motor 5 A micro control unit (MCU) that controls the steering assist force generated by the electric motor 5 by calculating a voltage command value to the pulse width modulation circuit of the power board 19B by performing current feedback control based on the detected value of 3 sets formed in the module component 19C and three sets of insertion holes 21a to 21c through which three sets of lead terminals 24a to 24c described later formed in the power board 19B are inserted. Three sets of insertion holes 22a to 22c through which the lead terminals 34a to 34c are inserted, and an external connection terminal 15c of the torque sensor 15 15f is a through-hole 23a~23d to be inserted is formed.

  Further, the power board 19B has discrete components such as an H bridge circuit composed of a power switching element such as a field effect transistor that drives and controls the electric motor 5, and a pulse width modulation circuit that drives the power switching element of the H bridge circuit. The three sets of lead terminals 24a to 24c that are mounted and configured with a metal substrate with high thermal conductivity that is directly fixed to the flat mounting surface 20a via, for example, heat radiation grease, are electrically connected to the control board 19A. It protrudes upward. Here, as shown in FIG. 9, the lead terminals 24 a to 24 c are provided with bent portions 25 in the middle so as to relieve stress when a relative position change between the control board 19 </ b> A and the power board 19 </ b> B occurs due to thermal expansion or the like. Is formed.

Further, as shown in FIGS. 9 and 10, the module component 19 </ b> C includes a base substrate 33 molded with a synthetic resin material having a substantially rectangular shape when viewed from above, and is controlled on the upper surface side of the base substrate 33. Three sets of lead terminals 34a, 34b, and 34c electrically connected to the substrate 19A protrude upward along the right edge and the lower edge.
Further, on the back side of the module component 19C, as shown in FIG. 9, motor currents such as a capacitor 35, relays 36 and 37 for power supply and fail-safe, a coil 38 for noise countermeasures, capacitors 39 and 40, and the like. Mounted parts whose shapes and sizes change due to size and vehicle layout constraints are centralized and held.

Further, as shown in FIG. 10, the three sets of lead terminals 34a, 34b, and 34c are bent so as to relieve stress when the relative position change between the control board 19A and the module component 19C occurs due to thermal expansion or the like. 34d is formed.
Furthermore, a pair of attachment portions 33 a and 33 b that are attached to the control unit mounting portion 20 of the reduction gear box 4 are formed on the diagonal line at the left and right ends of the base substrate 33, and the vertical direction on the upper surface of the base substrate 33 is formed. A support portion 33d having a positioning pin 33c for supporting the control board 19A is formed on the left side in FIG. 9 in the center portion.

  Here, the mounting portion 33a and 33b of the base substrate 33, the connecting portion 33e for connecting the mounting portions 33a and 33b through the side edge on the mounting portion 33a side of the base substrate, and the center position in the left-right direction of the connecting portion 33e. The mounting portion 33f attached to the control unit mounting portion 20 of the reduction gear box 4 provided in the housing is constituted by an integrated bus bar. Therefore, the bus bar can be electrically connected to the reduction gear box 4 to act as a ground for noise current return, and the rigidity of the base substrate 33 can be increased.

In addition, in FIG. 9 corresponding to the mounting portions 33a and 33b of the base substrate 33, positioning pins 33g and 33h that are inserted into the module component storage portion 20b of the reduction gear box 4 for positioning are projected and formed on the lower surface side.
Furthermore, as shown in FIG. 4, the motor terminal block 19 </ b> D includes a mounting portion 41 a that is molded with a synthetic resin material and is attached to a terminal block mounting portion 17 a that is formed on the motor mounting portion 17. A terminal plate holding portion 41b having an inclined surface formed on the upper portion, inclined terminal plates 41c and 41d in surface contact with the connection terminals 5c and 5d of the electric motor 5 formed on the terminal plate holding portion 41b, and these inclined terminals Lead terminals 41e and 41f are individually connected to the plates 41c and 41d and electrically connected to the control board 19A.

  Further, as shown in FIGS. 9 and 11, the connector 19E is formed by molding with a synthetic resin material, and includes a case body 44 having a power connector 42 and a signal connector 43 connected to an external network. A mounting flange portion 44 a is formed on the left and right ends of the case body 44. On the back surface of the case body 44, a power lead terminal 45 and a signal lead terminal 46 that are electrically connected to the control board 19A of each connector portion 42 and 43 are projected from the back side by a predetermined distance and then bent upward. It is formed in an L shape.

  In order to assemble the control unit 19, first, after applying thermal grease to the flat mounting surface 20a of the control unit mounting portion 20, the power board 19B is brought into contact with the positioning portion 20d at the corner on the lead terminal 24a side. In this state, it is fixed to the flat mounting surface by screwing or the like. Next, the base substrate 33 is mounted so that the module component 19C with the relay, capacitor, etc. mounted on the lower surface is stored in the module component storage unit 20b formed on the control unit mounting unit 20 with the relay, capacitor, etc. on the lower surface. It fixes by screwing etc. on the support piece 20f. Next, the motor terminal block 19D is placed on the terminal block mounting portion 17a formed on the motor mounting portion 17, and is fastened together with the mounting portion 33b of the module component 19C by screwing or the like. Next, the control board 19A is inserted through the lead terminals 24a-24c of the power board 19B into the insertion holes 21a-21c, the lead terminals 34a-34c of the module component 19C are inserted through the insertion holes 22a-22c, and the module component 19C The positioning pin 33c of the support portion 33d formed on the base substrate 33 is inserted into the insertion hole 33i and fixed by screwing or the like. Next, the mounting flange portion 44a of the connector 19E is placed on the connector support piece 20g of the control unit mounting portion 20, and then fixed to the connector support piece 20g by screwing or the like.

  By completing the above mounting process, the control board 19A, the power board 19B, and the module component 19C can be individually mounted on the control unit mounting portion 20 of the reduction gear box 4 as shown in FIG. Then, after soldering each lead terminal on the upper surface side of the control board 19A, the cover 19F shown in FIG. 4 is fixed to the control unit mounting portion 20 by screwing or the like, whereby the control unit 19 is configured. 19 is attached to the reduction gear box 4.

  Then, after the mounting of the control unit 19 on the reduction gear box 4 is completed, the electric motor 5 is mounted on the motor mounting portion 17 of the reduction gear box 4. At this time, since the output shaft of the electric motor 5 and the worm shaft 11a of the reduction gear box 4 are splined or serrated, the spline or serration is shallowly rotated while the electric motor 5 is rotated, and the shallow spline or serrated When the coupling is completed, the electric motor 5 is in-line coupled to the reduction gear box 4 after positioning so that the mounting flange 5b of the electric motor faces the flange portion 17b of the motor mounting portion 17 in the reduction gear box 4.

  In this way, the external connection terminals 5c and 5d of the electric motor 5 come into surface contact with the terminal plates 41c and 41d formed on the motor terminal block 19D in the control unit 19, and in this state, the external connection terminals of the electric motor 5 The external connection terminals 5c and 5d of the electric motor 5 and the terminal plates 41c and 41d of the motor terminal block 19D can be electrically connected by screwing from the opposite side to the motor terminal block 19D of the 5c and 5d. . At the same time, the electric motor 5 can be mounted on the reduction gear box 4 by bolting the motor-side mounting flange 5 b to the flange portion 17 b of the motor mounting portion 17.

Next, the operation of the above embodiment will be described.
First, to assemble the electric power steering device 1, the torque sensor 15 is placed in the torque sensor storage portion 16 of the reduction gear box 4, and the distal ends of the external connection terminals 15 c to 15 f are in the horizontal direction of the side wall 20 c in the control unit mounting portion 20. Through the opening 20h formed in the central portion, it is fixedly arranged so as to extend rearward of the vehicle body in parallel with the flat mounting surface 20a.

  Next, the control unit 19 is mounted on the control unit mounting portion 20 of the reduction gear box 4 while being assembled. As described above, the control unit 19 is assembled as follows. First, the power board 19B is fixed to the flat mounting surface 20a by screwing through a heat dissipating grease, and then the module component 19C is mounted with components such as a relay and a capacitor. In this state, the base substrate 33 is mounted on the support piece 20f while the base substrate 33 is stored in the module component storage unit 20b, and these are fixed by screwing or the like. Next, the motor terminal block 19D is fastened to the terminal block mounting portion 17a of the motor mounting portion 17 together with the mounting portion 33b of the module component 19C by screwing or the like.

  Then, with the lead terminals 45 and 46 of the connector 19E inserted through the insertion holes 48a and 48b of the control board 19A, the control board 19A is first inserted, and the external connection terminals 15c to 15f of the torque sensor 15 are first inserted into the through holes 23a to 23d. After being inserted, the lead terminals 24a to 24c of the power board 19B are inserted into the insertion holes 21a to 21c, the lead terminals 34a to 34c of the module component 19C are inserted to the insertion holes 22a to 22c, and the lead terminals of the motor terminal block 19D 41e and 41f are inserted into the insertion holes 41g and 41h, and at the same time, the positioning pins 33c of the module component 19C are inserted into the insertion holes 33i to be positioned and placed on the support piece 20e of the control unit mounting portion 20. At the same time, the mounting flange 44a of the connector 19E is connected to the connector support piece 20g. To location.

The control board 19A is fixed to the support piece 20e by screwing or the like, and the mounting flange portion 44a of the connector 19E is fixed to the connector support piece 20g by screwing or the like. In this case, the control board 19A may be fixed to the support piece 20e after the connector 19E is first fixed to the connector support piece 20g.
In this state, as shown in FIG. 2, the control board 19A, the power board 19B, the module component 19C, the motor terminal block 19D, and the connector 19E constituting the control unit 19 are mounted on the control unit mounting portion 20 of the reduction gear box 4. In this state, by soldering the lead terminals protruding from the upper surface of the control board 19A, the control board 19A, the power board 19B, the module component 19C, the motor terminal block 19D, and the connector 19E are electrically connected. And the control board 19A and the connector 19E are fixed.

When the soldering is completed, the cover 19F is mounted on the control unit mounting portion 20 so as to cover the control board 19A and fixed by screwing or the like, whereby the control unit 19 is assembled and the control unit mounting portion 20 is fixed. At the same time the installation to the.
Next, after attaching the steering shaft 2, the steering column 3, the worm 11, the worm wheel 13, and the like to the reduction gear box 4, the electric motor 5 is finally attached to the motor attachment portion 17 of the reduction gear box 4.

  When the electric motor 5 is mounted, first, the output shaft of the electric motor 5 and the worm shaft 11a to which the worm 11 housed in the worm housing portion 12 of the reduction gear box 4 is attached are in contact with each other. The electric motor 5 is shallowly splined or serrated while rotating in the circumferential direction. When the shallow spline coupling or serration coupling is completed, the electric motor 5 is rotated again in the circumferential direction so that the mounting flange 5b faces the flange portion 17b of the motor mounting portion 17, and the connection terminals 5c and 5d are connected to the motor terminal block 19D. The electric motor 5 is pushed into the reduction gear box 4 in an in-row connection with the terminal plates 41c and 41d facing each other.

  In this state, since the connection terminals 5c and 5d are in surface contact with the terminal plates 41c and 41d of the motor terminal block 19D, the connection terminals 5c and 5d and the terminal plates 41c and 41d are screwed with a tool such as a screwdriver in this state. The cover 19G shown in FIG. 4 is attached so as to cover the terminal block 19D. At this time, the connection terminals 5c and 5d and the terminal plates 41c and 41d are inclined leftward with respect to the axial direction of the electric motor 5 as shown in FIG. 2, so that a tool such as a screwdriver can be easily inserted. And can be easily screwed.

  In addition, since the connection terminals 5c and 5d and the terminal plates 41c and 41d are inclined to the upper right with respect to the axial direction of the electric motor 5, the contact area required for the connection terminals 5c and 5d and the terminal plates 41c and 41d However, the height of the motor terminal block 19D can be reduced, and the connection terminals 5c and 5d and the motor terminal block 19D can be reliably prevented from protruding more than necessary. Can be improved.

  Further, since the connection terminals 5c and 5d can be firmly attached at the shortest distance by making surface contact with the terminal plates 41c and 41d, the connection terminals 5c and 5d and the terminal plates 41c and 41d can be electrically connected without interposing a motor harness. In addition, the external connection terminals 15c to 15f of the torque sensor 15 and the through holes 23a to 23d of the control board 19A can be directly and electrically connected without a sensor harness. For this reason, the electrical connection length between the control unit 19 and the electric motor 5 and the torque sensor 15 can be minimized, wiring resistance can be minimized, power loss can be suppressed, and electric noise can be reduced. Riding can also be reduced.

Moreover, since it is not necessary to provide a motor harness between the electric motor 5 and the control unit 19, the noise radiated from the motor harness is reduced, and the influence on the radio noise can be reduced.
Further, the control unit 19 is roughly composed of a control board 19A, a power board 19B and a module component 19C, and the arrangement relationship thereof is as shown in FIG. 12, and the flat mounting surface in the control unit mounting portion 20 of the reduction gear box 4 is provided. A power board 19B is attached to 20a, and a control board 19A is stacked in parallel at a predetermined interval above the power board 19B. The power board 19B and the control board 19A are arranged in a single direction as viewed from the axial direction of the steering column 3. The module component 19C is arranged so as to be within the projection plane region, and the mounting components such as the capacitor 35 and the relay 36 are arranged on the left side of the power board 19B in FIG. The power board 19B and control board 19A in the direction and the module component 19C in the vertical direction are formed in an L shape. The three-layer structure of the power board 19B, the lead terminals 34a to 34c of the module component 19C and the control board 19A in the vertical direction so that the lead terminals 34a to 34c of the module part 19C are positioned between the power board 19B and the control board 19A. Has been. Therefore, the distance between the power board 19B and the control board 19A can be minimized, the thickness of the control unit 19 in the axial direction of the steering column 3 can be suppressed, and the reduction gear box 4 is internally provided. In order to greatly change the sizes of the worm 11 and the worm wheel 13, as shown in FIG. 13, the position of the module component storage portion 20b formed in the control unit mounting portion 20 of the reduction gear box 4 is shifted outward from the side wall 20c. When the distance needs to be increased from L1 to L2 shown in FIG. 12, the lengths of the bent portions of the lead terminals 34a to 34c of the module component 19C correspond to the length corresponding to the deviation amount of the module component storage portion 20b. By simply changing the length, it can be easily handled and versatility can be improved.

  Moreover, since the control board 19A, the power board 19B and the module part 19C are individually attached to the control unit mounting part 20 of the reduction gear box 4, the flat attachment surface 20a, the module part storage part 20b and the side wall 20c of the reduction gear box are provided. Is also used as a component of the control unit 19, the number of parts of the control unit 19 can be reduced, and the assembly of the control unit 19 and the mounting to the control unit mounting portion 20 can be performed simultaneously. The assembly man-hour can be reduced.

Further, the electrical connection of the control board 19A, the power board 19B and the module component 19C can be performed by soldering via the control board 19A, and the control board 19A, the power board 19B, the module part 19C and the torque sensor 15 can be connected. Can be soldered only on one surface, and the assembly work can be simplified.
Further, a flat mounting surface 20a in the control unit mounting portion 20 of the reduction gear box 4 in which the power board 19B with heat generation constituting the control unit 19 is formed of any one of aluminum, aluminum alloy, magnesium and magnesium alloy. Is directly contacted via the heat dissipating grease, so that the heat generated by the power board 19B can be dissipated to the reduction gear box 4 having a large heat capacity, and the power board 19B can be reliably prevented from being overheated. Can do.

Furthermore, by arranging the control unit 19 above the torque sensor housing portion 16 of the reduction gear box 4, the overall length of the reduction gear box 4 in the axial direction can be shortened and the size can be reduced.
In this state, after attaching the upper mounting bracket 6 and the lower mounting bracket 7 to the vehicle body side member, the external connection connector connected to the battery and the ground point to the power connector portion 42 and the signal connector portion 43 of the connector 19E in the control unit 19, respectively. And mounting | wearing with the connection connector of networks, such as CAN, completes the assembly | attachment of the electric power steering apparatus 1. FIG.

At this time, in the upper mounting bracket 6, as shown in FIG. 1, the sliding plate portion 6f is fixed to the capsule 6d constituting the mounting plate portion 6a by the resin injection 6e.
When the assembly of the electric power steering apparatus 1 is completed, the tilt lock state is released by rotating the tilt lever 6g of the upper mounting bracket 6, and in this state, the steering column 3 is pivoted on the pivot shaft 7c of the lower mounting bracket 7. The tilt position can be adjusted by rotating it around the center.

  When power is supplied from the battery to the control board 19A, the power board 19B, and the module component 19C by turning on an ignition switch (not shown) of the vehicle, a steering assist control process is executed by the micro control unit (MCU), and the torque sensor 15 A steering assist current command value is calculated based on a detection value of a vehicle speed sensor (not shown). A current feedback process is executed based on the steering assist current command value and the motor current detected by the motor current detection unit to calculate a voltage command value. By supplying this voltage command value to the gate drive circuit of the power board 19B and controlling the H-bridge circuit, a motor drive current flows through the electric motor 5, and the steering assist that requires the electric motor 5 in the forward or reverse direction. Drive to generate force.

For this reason, a steering assist force corresponding to the steering torque of the steering wheel is generated from the electric motor 5, and this steering assist force is transmitted to the output of the steering shaft via the worm 11 and the worm wheel 13, whereby the steering wheel is It can be steered with a light steering force.
In this state, when an occupant comes into contact with a steering wheel (not shown) when a collapse occurs and an impact force that slides the steering column 3 forward acts, a gap between the capsule 6d of the upper mounting bracket 6 and the sliding plate portion 6f. As the resin injection 6e is sheared, the outer tube 3b slides against the inner tube 3a while absorbing the impact force on the mounting flange 3c side of the steering column 3, and strikes against the torque sensor housing portion 16 as a contraction stopper. By contacting, the necessary collapse stroke is secured and the steering column 3 contracts.

  In the embodiment described above, the connection terminals 5c and 5d are provided in the electric motor 5, and the motor terminal block 19D is provided in the control unit 19. However, the present invention is not limited to this. A base may be provided, and a connection terminal may be provided in the control unit 19, and furthermore, both the motor side connection part of the electric motor 5 and the unit side connection part of the control unit 19 are set to connection terminals of the same angle or different angles. You can also. In this case, both connection terminals may be fixed by arbitrary fixing means such as soldering, welding, rivets, screws and nuts.

  Furthermore, although the case where the external connection terminals 15c to 15f of the torque sensor 15 are formed in an L shape has been described in the above embodiment, the present invention is not limited to this, and the external connection terminals 15c to 15f are linear. In addition, electrical connection may be made by soldering or fusing along a connection land formed on the control board 19A, or an external connection terminal may be clamped to the control board 19A as a clip terminal. .

Furthermore, in the above-described embodiment, the case where the flat mounting surface 20a of the control unit mounting portion 20 of the reduction gear box 4 is a plane orthogonal to the central axis of the steering column 3 has been described. However, the present invention is not limited to this. Instead, the first flat mounting surface 20 a may be a surface that is inclined with respect to a surface orthogonal to the central axis of the steering column 3.
Furthermore, in the above-described embodiment, the case where the worm gear is applied as the speed reduction mechanism has been described. However, the present invention is not limited to this, and a speed reduction mechanism or a belt type in which any gear such as a bevel gear or a spur gear is combined It is possible to apply a speed reduction mechanism of any configuration.

In the above embodiment, the case where a coil-type torque sensor is applied as the torque sensor 15 has been described. However, the present invention is not limited to this, and a torque sensor that detects the torsion angle of the torsion bar 2b is applied. You can also.
Furthermore, in the above-described embodiment, the case where a brush motor is applied as the electric motor 5 has been described. However, the present invention is not limited to this, and a brushless motor may be applied. The terminals 5c and 5d are connected to the power supply side of the excitation coil of each phase, and the inverter circuit having, for example, a field effect transistor (FET) for driving the brushless motor on the power board 19B and the gate of the field effect transistor of the inverter circuit are pulse widths. A gate driving circuit driven by a modulation signal may be mounted.

1 is a perspective view showing an embodiment of an electric power steering device according to the present invention. It is a perspective view in the state where an electric motor and a control unit are attached to a reduction gear box. It is a longitudinal cross-sectional view which expands and shows a part of reduction gear box. It is a disassembled perspective view of a reduction gear box. It is a perspective view which shows an electric motor. It is a front view showing the bus bar structure of the electric motor. It is the perspective view seen from the front side of the reduction gear box. It is the perspective view seen from the back side of the reduction gear box. It is a disassembled perspective view of a control unit. It is the perspective view which looked at the module components from the opposite side to FIG. It is a perspective view which shows a connector. It is a schematic diagram showing the cross section of a control unit. It is a schematic diagram showing the cross section at the time of the deceleration mechanism size change of a control unit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering device, 2 ... Steering shaft, 3 ... Steering column, 4 ... Reduction gear box, 5 ... Electric motor, 5c, 5d ... Connection terminal, 5i, 5j ... Bus bar, 6 ... Upper mounting bracket, 7 ... Lower Mounting bracket, 11 ... worm, 11a ... worm shaft, 12 ... worm housing portion, 13 ... worm wheel, 14 ... worm wheel housing portion, 15 ... torque sensor, 16 ... torque sensor housing portion, 17 ... motor mounting portion, 18 ... Column mounting part, 19 ... control unit, 19A ... control board, 19B ... power board, 19C ... module parts, 19D ... motor terminal block, 19E ... connector, 19F, 19G ... cover, 20 ... control unit mounting part, 20a ... flat Mounting surface, 20b ... module component storage, 20c ... side wall

Claims (6)

A column assist type electric power steering apparatus including a steering column having a steering shaft to which a steering torque is transmitted, and an electric motor for transmitting a steering assist force to the steering shaft via a reduction mechanism in a reduction gear box. There,
The reduction gear box is provided with a motor mounting portion for mounting the electric motor and a control unit mounting portion for mounting a control unit for driving and controlling the electric motor, and the control unit calculates at least a command value. Control board, a power board on which the switching element for the electric motor is mounted, and a module part on which mounting parts such as a relay and a noise countermeasure part are mounted. The electric power is characterized in that the control boards are stacked in that order at a predetermined interval, and the module parts are electrically connected to each other so as to be positioned between the control board and the power board. Steering device.   The electric connection according to claim 1, wherein the electrical connection among the control board, the power board, and the module component is performed by soldering connection terminals of the power board and the module component to the control board. Power steering device.   The control board and the power board are disposed so as to be within one projection plane region parallel to the unit mounting portion, and the module component includes an electrical connection portion to the control board. The electric power steering apparatus according to claim 1, wherein the electric power steering apparatus is disposed between power boards, and the mounted component is disposed outside the projection surface area.   The electric power steering apparatus according to any one of claims 1 to 3, wherein a storage portion for storing the mounted component of the module component is formed in the reduction gear box.   The said module component is provided with the bus-bar comprised by a pair of attachment part attached to the said reduction gear box, and the connection part which connects between the said pair of attachment parts. The electric power steering apparatus according to item 1.   The reduction gear box includes a torque sensor that detects a steering torque transmitted to the steering shaft, and an external connection terminal of the torque sensor is directly connected to the control board. The shape of the electrical connection part of the module part is changed according to the change of the relative position when the relative position of the control board and the module part changes due to the shape change. The electric power steering apparatus according to any one of 1 to 5.

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