JP5334923B2 - Electric power steering device - Google Patents

Description

  The present invention relates to an electric power steering apparatus including an electric motor that outputs assist torque to a steering wheel of a vehicle and a drive control device that controls driving of an output shaft of the electric motor.

Conventionally, a motor housing of an electric motor that outputs an assist torque to a steering wheel of a vehicle and a drive housing of a drive control device that controls driving of the output shaft of the electric motor are fixed at a mating surface, and There is known an electric power steering device in which a motor housing and a gear housing containing a gear connected to the output shaft are coupled on the same axis (for example, Patent Document 1).
In this electric power steering device, the electric motor and the drive control device are integrated to reduce the overall size of the device, and the length of the electrical wiring that electrically connects the two is minimized. The cost can be reduced by reducing the power consumption, or the power loss and noise can be reduced.

Japanese Patent No. 3638269 (FIG. 3, paragraph 0072)

The electric power steering device is mounted on a vehicle body in a vehicle production line as a power steering mechanism integrated with a handle, a column shaft, and the like.
Generally, when replacing the entire electric power steering device, the power steering mechanism is first removed from the vehicle body, and then the electric power steering device is replaced.
When replacing the electric power steering device, there are cases where it is desired to replace only the drive control device having a high failure rate because it contains many semiconductor components.
In this case, in the electric power steering apparatus, since the connection portion for connecting the connection portion of the electric motor and the connection portion of the drive control device is in the connection portion between the motor housing and the gear housing, the electric power steering device is temporarily removed from the gear housing of the power steering mechanism. After removing the electric power steering device and then removing the screw in the electrical connection through the opening on the gear housing side of the motor housing, the drive control device must be removed and replaced from the electric motor. There was a problem of being bad.

  An object of the present invention is to solve such a problem. When the drive control device is replaced, it is possible to replace only the drive control device without removing the electric power steering device from the gear housing. An object of the present invention is to provide an electric power steering device in which the drive workability of the drive control device is greatly improved.

In the electric power steering device according to the present invention, the motor housing of the electric motor that outputs assist torque to the steering wheel of the vehicle and the drive housing of the drive control device that controls the driving of the output shaft of the electric motor are in surface contact. An electric power steering device in which a motor housing and a gear housing containing a gear connected to the output shaft are coupled on the same axis, and coupled on a mating surface,
The connection part where the connection part of the electric motor and the connection part of the drive control device are electrically connected is provided at a joint part where the end of the motor housing and the drive housing are joined,
The drive control device is provided on a side overlapping with the gear housing when viewed along a direction perpendicular to the axis.
The connection parts are connected from the opposite side to the gear housing by a fixing member,
Further, the joining portion is joined from the opposite side of the gear housing by a screw,
The mating surface is a surface perpendicular to the radial direction of the axis,
The connecting portions are connected by the fixing member that moves in a direction perpendicular to the mating surface.

  According to the electric power steering apparatus according to the present invention, the connection portion where the connection portion of the electric motor and the connection portion of the drive control device are electrically connected is the connection portion where the motor housing and the end portion of the drive housing are bonded. Therefore, after the electric power steering device is mounted on the gear housing, only the drive control device can be attached and detached without removing the electric motor from the gear housing, improving the repair and replacement workability of the drive control device. To do.

It is a perspective view which shows the power steering mechanism in which the electric power steering apparatus of Embodiment 1 of this invention was integrated. It is a block diagram which shows the electric power steering apparatus of FIG. It is a perspective view which shows the electric power steering apparatus of FIG. It is a disassembled perspective view which shows the electric power steering apparatus of FIG. It is a perspective view which shows the electric power steering apparatus of Embodiment 2 of this invention. It is a perspective view which shows the electric power steering apparatus of the reference example 1 of this invention. It is a perspective view which shows the electric power steering apparatus of the reference example 2 of this invention. It is a perspective view which shows the electric power steering apparatus of the reference example 3 of this invention. It is a perspective view which shows the electric power steering apparatus of the reference example 4 of this invention.

  Hereinafter, embodiments and reference examples of the present invention will be described with reference to the drawings. In the drawings, the same or equivalent members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a perspective view showing a power steering mechanism in which an electric power steering device 20 is incorporated, FIG. 2 is a block diagram of the electric power steering device 20 of FIG. 1, and FIG. 3 is a perspective view of the electric power steering device 20 of FIG. FIG. 4 is an exploded perspective view of the electric power steering apparatus 20 of FIG.
In the power steering mechanism, the steering force from the vehicle handle 26 is transmitted through the column shaft 21. The electric power steering device 20 is attached to the column shaft 21 via a gear housing 22 that houses a worm gear. The output (torque, rotation speed) of the output shaft of the electric motor 1 of the electric power steering device 20 is transmitted to the handle joint 23 after the rotation direction is changed to a right angle by the worm gear and decelerated.
A steering gear housed in a gear box 24 is provided at the end of the handle joint 23. This steering gear transmits the rotational motion to the rack 25 as a linear motion, and the rack 25 obtains the required transition. The wheels are interlocked with the linear motion of the rack 25, and the direction of the vehicle can be changed.

  The electric power steering device 20 includes an electric motor 1 that outputs an assist torque to a handle 26, a drive control device 6 that controls driving of an output shaft of the electric motor 1, and a current for driving the electric motor 1. A battery 4 that supplies the steering wheel, a torque sensor 5 that detects steering torque of the steering wheel, a motor connector 15 that is a connection part where the drive control device 6 and the electric motor 1 are electrically connected, and the battery 4 and the drive control device 6. And a signal connector 17 that electrically connects the electric motor 1, the torque sensor 5, and the drive control device 6.

An electric motor 1 that is a three-phase brushless motor includes an output shaft, a rotor having a permanent magnet having eight magnetic poles fixed to the output shaft, a stator provided around the rotor, and an output shaft. And a rotational position sensor 3 for detecting the rotational position of the rotor.
The stator is fixed to the inner wall surface of the bottomed cylindrical motor frame 30 on the side opposite to the drive control device 6 of the motor housing 31. The stator is composed of 12 salient poles opposed to the outer periphery of the permanent magnet, and armature windings 2 (2u, 2v, 2w) attached to the salient poles and connected to three phases U, V, and W. And have.

  The drive control device 6 includes a large-capacity capacitor 7 for absorbing the ripple component of the motor current IM flowing through the electric motor 1, a shunt resistor 8 for detecting the motor current IM, and assisting the motor current IM with the assist torque. Are provided with a three-phase bridge circuit 10 composed of a plurality of semiconductor switching elements Q1 to Q6 for switching according to the size and direction, a coil 11 for removing electromagnetic noise, and a control circuit 12.

  The control circuit 12 calculates the assist torque based on the steering torque signal, current detection means 9 for detecting the current flowing through the electric motor 1 through one end of the shunt resistor 8, and the motor current IM and the rotor. And a microcomputer 13 that calculates a current corresponding to the assist torque by feeding back the rotational position of the motor. The microcomputer 13 sends a drive signal for controlling the bridge circuit 10 to the bridge circuit 10 via the drive circuit 14. It is designed to output.

  In the electric power steering device 20, the motor housing 31 of the electric motor 1 that outputs assist torque to the handle 26 of the vehicle and the drive housing 36 of the drive control device 6 that controls driving of the output shaft of the electric motor 1 are provided. The mating surface A that is in surface contact with the pedestals 31a and 36a is connected by four screws 46. The electric power steering device 20 is coupled on the same axis as the gear housing 22 in which a motor housing 31 houses a worm gear connected to an output shaft. The drive control device 6 is provided on the side overlapping the gear housing 22 when viewed along the direction perpendicular to the axis. The mating surface A is a surface perpendicular to the radial direction of the axis.

In the drive housing 36, a capacitor 7, a shunt resistor 8, a three-phase bridge circuit 10 including a plurality of semiconductor switching elements Q1 to Q6, a coil 11, a control circuit 12, and the like are housed.
The opening of the drive housing 36 is closed by a cover 44 using four screws 45.

The pedestal portion 31 a of the motor housing 31 is provided with a power input terminal block 32 that is a connection portion. A terminal 33 for each phase electrically connected to the armature winding 2 (2u, 2v, 2w) is laid on the power input terminal block 32. A nut (not shown) is embedded in the back side of the terminal 33 of each phase.
Each terminal 33 is connected using a power supply bus bar 37 which is a connection portion exposed from the inside of the drive control device 6 and a screw 40 which is a fixing member.
An opening is formed in the upper part of the pedestal 36a of the drive housing 36, and this opening is closed by a cover 41 with a screw 42 through an O-ring 27, which is a silicon sealing member.
By closing the cover 41, the power input terminal block 32 and the power supply bus bar 37 are confined in a chamber 39 surrounded by a wall surface and blocked from the outside. Note that silicon O-rings 34 and 35 are provided around the power input terminal block 32 in order to ensure the airtightness of the chamber 39 more reliably and to be waterproof and dustproof.

Next, a procedure for attaching the drive control device 6 to the electric motor 1 of the electric power steering device 20 will be described.
First, the pedestal portion 31 a of the motor housing 31 of the electric motor 1 assembled separately and the pedestal portion 36 a of the drive housing 36 of the drive control device 6 are brought into surface contact with each other and are coupled using the screws 46. At this time, each terminal 33 of the power input terminal block 32 and each power supply bus bar 37 are in surface contact.
Thereafter, the screws 40 as the fixing members are fastened to join the terminals 33 and the power supply bus bars 37 together. Subsequently, after the opening of the chamber 39 is closed with the cover 41, the cover 41 is joined to the upper surface of the pedestal 36 a of the drive housing 36 by fastening screws 42 at the four corners of the cover 41.

When removing the drive control device 6 from the electric power steering device 20, first, the four screws 42 are removed, and the cover 41 is removed from the base portion 36 a of the drive housing 36.
The power supply bus bar 37 that is the connection part on the drive control device 6 side and the power input terminal block 32 that is the connection part on the electric motor 1 side are exposed, and the screws 40 are subsequently removed, and the four screws 46 are removed. Thus, the drive control device 6 can be detached from the electric motor 1.
That is, the drive control device 6 can be detached from the electric motor 1 without removing the electric motor 1 from the gear housing 22.
The moving directions of the screws 46, 40, 42, the cover 41, and the drive control device 6 in this series of attachment and removal operations are perpendicular to the mating surface A.

Next, the operation of the electric power steering apparatus 20 having the above configuration will be described.
The microcomputer 13 takes in the steering torque from the torque sensor 5 and the rotational position of the rotor of the electric motor 1 from the rotational position sensor 3, and feedback inputs the motor current IM from the shunt resistor 8 via the current detection means 9. A current control amount corresponding to the rotation direction command and assist torque of the power steering is generated and input to the drive circuit 14. When the rotation direction command and the current control amount are input, the drive circuit 14 generates a PWM drive signal and applies it to the semiconductor switching elements Q <b> 1 to Q <b> 6 of the bridge circuit 10.
As a result, a current flows from the battery 4 to the electric motor 1 through the external wiring, the power connector 16, the coil 11, the bridge circuit 10, the motor connector 15, and the external wiring, and a required amount of assist torque is output in a required direction.

According to the electric power steering device 20 having the above-described configuration, the motor connector 15 in which the power input terminal block 32 that is the connection portion of the electric motor 1 and the power supply bus bar 37 that is the connection portion of the drive control device 6 are connected. Since the connection part which is a component is provided at the joint part where the base part 31a of the motor housing 31 and the base part 36a of the drive housing 36 are joined, without removing the electric motor 1 from the gear housing 22, The drive control device 6 can be detached from the electric motor 1, and the workability of repair and replacement of the drive control device 6 is improved.
In the drive control device 6, the power supply bus bar 37 may have a simple configuration extending into the chamber 39 connected to the power input terminal block 32, and there are many design restrictions on the drive control device 6. Is suitable.
The motor housing 31 of the electric motor 1 is coupled to the gear housing 22 and has higher rigidity than the drive housing 36 of the drive control device 6, and is used for power input provided in the high-rigidity motor housing 31. The connection reliability of the power supply bus bar 37 to the terminal block 32 is improved.

  Further, since the mating surface A of the pedestal portion 31a and the pedestal portion 36a is a surface perpendicular to the radial direction of the axis, it is suitable when there is a space in the radial direction and has a sufficient space in the radial direction. Therefore, the mating surface A can be surely aligned, and erroneous assembly or assembly failure can be prevented.

  Also. The electric motor 1 and the drive control device 6 are electrically connected to the power supply input terminal block 32 and the power supply bus bar 37 by fastening screws 40 that advance and retreat in the vertical direction with respect to the mating surface A. Therefore, it is suitable when there is a space in the radial direction, and the power supply bus bar 37 can be reliably joined to the power supply input terminal block 32 from the radial direction with a sufficient space.

  Further, since the power input terminal block 32 and the power supply bus bar 37 are arranged in a chamber 39 formed inside the pedestal portion 36a, the screws 40 are removed and attached when the drive control device 6 is replaced. Damage to components inside the drive housing 36 and the motor housing 31 that occur during work can be avoided.

  Moreover, since the opening part of the chamber 39 is closed by the detachable cover 41, it is possible to prevent foreign matter and water from entering the chamber 39.

  Further, since the forward and backward directions of the screws 40, 42, and 46 are perpendicular to the mating surface A, when determining the mounting position of the electric power steering device 20 on the gear housing 22, the operator There is a design merit that the layout of the steering gear is easy, such as setting in a direction that secures a space where the arm, tool, and drive control device 6 can be taken out.

Further, since the drive control device 6 is provided on the side overlapping the gear housing 22 when viewed along the direction perpendicular to the axis, the dimension in the axis direction can be reduced.
Further, there are many cases where a relatively large space is provided around the gear housing 22, which is suitable in such a case.

Embodiment 2. FIG.
FIG. 5 is a perspective view of the electric power steering apparatus 20 according to the second embodiment.
In this embodiment, the power supply terminal block 47 and the power input bus bar 49, which are connecting portions, are both disposed in the drive housing 36. The power input bus bar 49 extends in the radial direction from the motor housing 31 side.
The power input bus bar 49 is in surface contact with the terminal of the power supply terminal block 47, and the power input bus bar 49 is joined to the terminal of the power supply terminal block 47 by fastening the screw 40 in the axial direction.
The opening of the drive housing 36 is closed by a cover 44 using six screws 45. Further, an O-ring (not shown) is provided between the drive housing 36 and the cover 44 to ensure airtightness.
Other configurations are the same as those of the first embodiment.

  In this embodiment, when only the drive control device 6 is removed, first, the six screws 45 are removed and the cover 44 is opened. Then, since the power supply terminal block 47 is exposed, the three screws 40 are removed, and the four screws 46 are subsequently removed, so that only the drive control device 6 can be removed without removing the electric motor 1 from the gear housing 22. The electric motor 1 can be removed.

In the first embodiment, the advancing and retreating directions of the screws 40, 42, and 46 are all the same radial direction. In this embodiment, the advancing and retreating direction of the screw 40 that is the fixing member is the axial direction. Although it is slightly inferior, the electric motor 1 side may have a simple configuration in which the power input bus bar 49 extends into the chamber 39 and is suitable when there are many design restrictions such as the size of the electric motor 1. .
Further, the cover 44 also closes the opening of the chamber 39, the cover 41 in the first embodiment is unnecessary, the number of parts is reduced, and the cost is lower than that in the first embodiment.
Other effects are the same as those of the first embodiment.

Reference Example 1
6 is a perspective view of the electric power steering apparatus 20 of Reference Example 1. FIG.
In this reference example, the drive control device 6 is different from the first embodiment in that the drive control device 6 is provided on the side overlapping the electric motor 1 when viewed along the direction perpendicular to the axis.
Other configurations are the same as those of the first embodiment.

In this reference example, when there is no space around the radial direction of the gear housing 22, it is preferable in that the drive control device 6 can be arranged at the opposite position.
Other effects are the same as those of the first embodiment.

Reference Example 2
FIG. 7 is a perspective view of the electric power steering device 20 of Reference Example 2. FIG.
In this reference example, the mating surface A between the pedestal portion 31 a of the motor housing 31 and the pedestal portion 36 a of the drive housing 36 is a plane perpendicular to the axis of the electric motor 1.
Other configurations are the same as those of the first embodiment.

In the first embodiment, the advancing and retreating directions of the screws 40, 42, and 46 are all perpendicular to the mating surface A. In this reference example, the advancing and retreating direction of the screw 46 is the axial direction. Although it is slightly inferior in performance, it is suitable for a vehicle layout in which the large-sized drive control device 6 can be attached and detached only in the axial direction of the electric motor 1.
Other effects are the same as those of the first embodiment.

Reference Example 3.
FIG. 8 is a perspective view of the electric power steering apparatus 20 of Reference Example 3.
In this reference example, the mating surface A of the pedestal portion 31a of the motor housing 31 and the pedestal portion 36a of the drive housing 36 is a surface perpendicular to the radial direction of the axis of the electric motor 1, and the drive control device 6 is The electric motor 1 is provided so as to extend in a direction perpendicular to the axis.
Other configurations are the same as those of the second embodiment.

In the first embodiment, the forward and backward directions of the screws 40, 42, and 46 are the same vertical direction. In this reference example, the forward and backward direction of the screw 46 is the vertical direction, and the forward and backward directions of the other screws 40 and 42 are the same. Is the horizontal direction, and the advancing and retreating directions of the screws 40, 42, and 46 are not the same, and the assembly workability is slightly inferior to that of the first embodiment.
However, vibration excitation is generally applied in a direction perpendicular to the axis of the electric motor 1, but in this reference example, the mating surface A is a surface perpendicular to the radial direction of the axis, It coincides with the longitudinal direction of the drive control device 6. Therefore, higher vibration resistance can be ensured as compared with those of Embodiments 1 and 2 and Reference Examples 1 and 2, in which the drive control device 6 is supported in a cantilever manner with respect to the electric motor 1.
Other effects are the same as those of the first embodiment.

Reference Example 4
FIG. 9 is a perspective view of the electric power steering apparatus 20 of Reference Example 4.
In this reference example, the power supply terminal block 47 extending from the drive housing 36 is located in a chamber 39 formed in the motor housing 31. A mating surface A between the pedestal 31 a of the motor housing 31 and the pedestal 36 a of the drive housing 36 is a plane perpendicular to the axis of the electric motor 1. The drive control device 6 is provided on the side overlapping the electric motor 1 when viewed along a direction perpendicular to the axis.
Other configurations are the same as those of the second embodiment.

In this reference example, the forward and backward directions of the screws 40, 42, 46 are the same horizontal direction, and the attachment / detachment of the drive control device 6 from the electric motor 1 and the power supply terminal block 47 and the power input bus bar 49 are performed. Since the operations for connecting and disconnecting are integrated in the same direction, the same effect as in the first embodiment can be obtained.
In particular, since the handle joint 23 stands in a direction perpendicular to the vehicle horizontal direction (horizontal direction of the ground), work such as attachment / detachment is performed from the vehicle side direction, and the electric power steering device 20 is attached to the column shaft 21. Work can be done in the vehicle horizontal direction from inside the vehicle cabin, and the work efficiency is better.
Further, when there is no space around the radial direction of the gear housing 22, it is preferable in that the drive control device 6 can be disposed at the opposite position.
Other effects are the same as those of the first embodiment.

In each embodiment and each reference example, the screws 40, 42, and 46 are used for assembling and electrical connection between the electric motor 1 and the drive control device 6. However, the present invention is not limited to this.
For example, the connection between the terminals of the terminal blocks 32 and 47 and the bus bars 37 and 49 may be connector fitting, caulking, TIG welding, fusing, etc., and the cover 41 of the chamber 39 may be snap fit, heat caulking, resin Packing adhesion or the like may be used.
In each embodiment and each reference example, the brushless motor type electric motor 1 has been described. However, an electric power steering apparatus using another motor such as an induction machine may be used.

In each embodiment and each reference example, the connection part of the three-phase wiring that inputs and outputs the drive current between the electric motor 1 and the drive control device 6 has been described, but the rotational position sensor 3 of the electric motor 1 and The present invention can also be applied to the connection part of the signal line that transmits and receives a signal to and from the control circuit 12 of the drive control device 6 as in the connection part of the three-phase wiring.
In this case, it is necessary to arrange the signal line connection part in the chamber 39 along with the connection part of the three-phase wiring, and although the space in the chamber 39 is slightly increased, the same effect can be obtained. it can.
In addition, in addition to the signal line of the rotational position sensor 3, if the electric motor has components for transmitting and receiving signals to and from the drive control device 6 such as a current sensor and a temperature sensor, of course, the connection part of these signal lines is connected This invention can also be applied.

Also, the column assist type electric power steering device 20 in which the electric power steering device 20 is mounted on the column shaft 21 and the column shaft 21 is torque-assisted by an electric motor has been described. However, the present invention directly relates to a rack or a pinion on the rack. The present invention can also be applied to a rack assist type and pinion assist type electric power steering device that assists the motor with the torque of the electric motor.
In this case, the electric power steering apparatus is mounted on the lower part of the vehicle on the rack, but the present invention can be applied according to the layout of surrounding vehicle members and other parts.

In addition, after applying the present invention and exchanging the drive control device 6, it is necessary to match and adjust each control parameter between the drive control device 6 and the electric motor 1.
In this case, it may be carried out by investigating the external communication device of the operator, but it is desirable that the electric power steering device 20 itself performs automatic adjustment at the time of the first energization and drive after replacement, and the work efficiency is higher. It becomes.
In particular, in such a case, it is suitable for the electric power steering apparatus 20 in which the drive control apparatus 6 and the electric motor 1 having no external three-phase wiring are integrated as in the present invention, in which the adjustment accuracy degradation due to disturbance is small. It is.

  DESCRIPTION OF SYMBOLS 1 Electric motor, 2 Armature winding, 6 Drive control apparatus, 15 Motor connector, 20 Electric power steering apparatus, 22 Gear housing, 30 Motor frame, 31 Motor housing, 32 Power supply terminal block (connection part), 33 terminal , 34, 35 O-ring (seal member), 36 drive housing, 37 power supply bus bar (connection part), 39 chambers, 40, 42, 45, 46 screws, 41 cover, 47 power supply terminal block (connection part) , 48 Output shaft, 49 Bus bar for power input (connection part).

Claims (9)

A motor housing of an electric motor that outputs an assist torque to a vehicle handle and a drive housing of a drive control device that controls driving of the output shaft of the electric motor are coupled to each other at a mating surface, and the motor housing And an electric power steering device in which a gear housing containing a gear connected to the output shaft is coupled on the same axis,
The connection part where the connection part of the electric motor and the connection part of the drive control device are electrically connected is provided at a joint part where the end of the motor housing and the drive housing are joined,
The drive control device is provided on a side overlapping with the gear housing when viewed along a direction perpendicular to the axis.
The connection parts are connected from the opposite side to the gear housing by a fixing member,
Further, the joining portion is joined from the opposite side of the gear housing by a screw,
The mating surface is a surface perpendicular to the radial direction of the axis,
The electric power steering apparatus , wherein the connection portions are connected by the fixing member that moves in a direction perpendicular to the mating surface .   The electric power steering apparatus according to claim 1, wherein the connection portion is disposed in the motor housing.   The electric power steering apparatus according to claim 1, wherein the connection portion is disposed in the drive housing. The electric power steering apparatus according to any one of claims 1 to 3 , wherein the connection portion is provided in a room formed by being surrounded by a wall surface. The electric power steering apparatus according to claim 4 , wherein the chamber is hermetically sealed by a seal member provided around the chamber. 6. The electric power steering apparatus according to claim 5 , wherein the opening of the chamber is closed with a removable cover. The electric power steering apparatus according to claim 6 , wherein the attaching / detaching direction of the cover and the advancing / retreating direction of the fixing member are the same direction. The connection part of the electric motor is a power input bus bar connected to an armature winding, and the connection part of the drive control device is a power supply in which a terminal in surface contact with the power input bus bar is laid. The electric power steering device according to any one of claims 1 to 7 , wherein the electric power steering device is a terminal block. The connecting portion of the electric motor is a power input terminal block connected to an armature winding and a terminal is laid, and the connecting portion of the drive control device is connected to the terminal of the power input terminal block. The electric power steering apparatus according to any one of claims 1 to 8 , wherein the electric power steering apparatus is a bus bar for power supply in surface contact.

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