JPH0686583A - Electric motor - Google Patents

Abstract

PURPOSE:To provide a small, low-cost and reliable electric motor. CONSTITUTION:Each pair of coils 50a and 50b, 52a and 52b or 54a and 54b for each phase in a brushless motor are individually supplied with a current through power wires U1, V1, W1, U2, V2, and W2. When the left and right rear wheels rotate, transistors Tru1, Trv1, and Trw1 on the power side and transistors Tru2, Trv2, and Trw2 on the earth side are switched in a given sequential combination. The coils are sequentially excited to rotate a permanent magnet. Since two power wires are provided in parallel, the brushless motor 34 can be rotated even if one of the power wires is down. In addition, the pair of coils for each phase may be individually connected and two coil groups are formed so that each coil is controlled by different drivers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor, and more particularly to improving reliability.

[0002]

2. Description of the Related Art There are various kinds of electric motors such as a commutator motor, a brushless motor, a stepping motor, a rotary motor that produces rotation, and a linear motor that produces linear motion. Generally, these electric motors are (a) provided with a coil that generates a magnetic field by supplying an electric current and (b) relatively movable with respect to the coil, and generate a driving force between the coil by the generation of the magnetic field. A driving force generating member,
(C) a power supply for supplying a current to the coil, (d) a power supply line connecting the coil and the power supply, and (e) a controller provided on the power supply line for controlling the supply of the current from the power supply to the coil. Is configured to include. Either the coil or the driving force generating member is moved by the driving force generated in the driving force generating member, and the driven object member is moved.

In such an electric motor, if a failure occurs in a motor component member such as the coil, the driven object member cannot be moved. So, for example,
In the electric motor described in Japanese Patent Laid-Open No. 4-59479, two coils, two driving force generating members, two power supply lines, and two controllers are provided. This electric motor is
A commutator motor for a drive wheel steering device of an automobile, in which electric current is supplied to a coil through a controller composed of a commutator and a brush, the coil rotates with respect to a permanent magnet as a driving force generating member, and a steering gear The pinion that constitutes the device is rotated, and two sets of coils, permanent magnets, power supply lines, and controllers are provided. Therefore, even if one of the components of the same type fails, the motor is rotated by the operation of the other component and the drive wheels can be steered, so that running stability is not impaired.

[0004]

However, if two coils, two driving force generating members, one power source line and two controllers are provided in this manner, the electric motor becomes large in size and the cost can be avoided. Absent. An object of the present invention is to provide a small-sized, inexpensive and highly reliable electric motor.

[0005]

In order to solve the above-mentioned problems, the present invention provides the above-mentioned (a) coil, (b) driving force generating member, (c) power supply, (d) power supply line and (e). In an electric motor including a controller, at least the longer part of the part between the power source of the power supply line and the controller and the part between the controller and the coil is provided in parallel. To do.

[0006]

With this configuration, even if one of the plurality of power supply lines is disconnected, another power supply line supplies a current to the coil, and the electric motor can move the driven object member.

[0007]

Of the members constituting the electric motor, the most frequent failure is the long extending portion of the power supply line,
According to the present invention, the reliability of the electric motor can be improved by only providing at least the longer part of the part between the power source of the power supply line and the controller and the part between the controller and the coil in parallel. It is possible to obtain a small, inexpensive and highly reliable electric motor as compared with the case where a plurality of coils, driving force generating members, power source lines and controllers are provided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a brushless motor of a driving wheel steering system for an automobile will be described in detail with reference to the drawings. In FIG. 2, reference numeral 10 denotes an automobile body, and the body 10 has steering wheels such as left and right front wheels 12, 14.
And the left and right rear wheels 16, which are driving wheels and steering wheels,
18 is attached.

The left and right front wheels 12, 14 are front wheel steering devices 20.
Is rotated by. The front wheel steering system 20 includes a steering wheel 24 attached to one end of a steering shaft 22, and the rotation applied to the steering wheel 24 by a driver is converted into a linear motion by a pinion 26 and a rack 28, so that the tie rod 24 is rotated. Also, the knuckle arm transmits the left and right front wheels 12 and 14, and the left and right front wheels 12 and 14 are rotated in the same direction as the steering direction of the steering wheel 24.

The left and right rear wheels 16 and 18 are rear wheel steering devices 32.
Is rotated by. The rear wheel steering device 32 uses a brushless motor 34 as a power source, and the rotation of the brushless motor 34 is converted into a linear motion by a steering gear device 36 and transmitted to the left and right rear wheels 16 and 18, and the left and right rear wheels 1
6, 18 are rotated.

The rotation of the brushless motor 34 is controlled by the electronic control unit 40 via a driver 42 as a controller. The electronic control unit 40 includes a sensor group 44 such as a vehicle speed sensor, a yaw rate sensor, a steering angle sensor, and an encoder that detects the rotation amount of the brushless motor 34.
Each of the detection results of the left and right rear wheels 1 is supplied to the electronic control unit 40 based on the detection results.
The brushless motor 3 calculates the steering directions and the steering angles of the steering wheels 6 and 18, and obtains the steering directions and the steering angles.
Control rotation of 4.

The structure of the brushless motor 34 is shown in FIG. The brushless motor 34 is a three-phase motor,
The stator has two coils 50a for each phase,
50b, 52a, 52b, 54a, 54b are provided. Each of these three sets of coils has a power supply line U,
A current is supplied from the power supply 56 by V and W. Also,
Power cables U, V, W are provided with ground cables 58,
60 and 62 are connected.

Power supply lines U, V, W are provided with power supply side power transistors Tr _u1 , Tr _v1 , Tr _w1 , respectively.
The ground cables 58, 60, 62 are provided with ground-side power transistors Tr _u2 , Tr _v2 , Tr _w2 , respectively, and these power transistors Tr _u1 , Tr _v1 , T are provided.
The driver 42 is composed of r _w1, Tr _u2 , Tr _v2 , and Tr _w2 .

Power supply side power transistors Tr _u1 , Tr _v1 , Tr _w1 of power supply lines U, V, W and coils 50a, b, 52
The portions between a, b, 54a and 54b are each constituted by _two parallel power supply lines U ₁ , U ₂ , V ₁ and V ₂ and W ₁ and W ₂ , _{two for} each phase. Coil of 50
Currents are independently supplied to a, b, 52a, b, 54a, and b.

Coils 50a, b, 52a, b, 54a,
In b, a current is sequentially supplied by switching the power transistors Tr _u1 , Tr _v1 , Tr _w1 and Tr _u2 , Tr _v2 , Tr _w2 to generate a magnetic field, which serves as a rotatably provided driving force generating member. Rotational torque is generated between the permanent magnets (not shown) and the coils 50a, b, 52a, b, 54a, b, and the permanent magnets rotate to rotate the left and right rear wheels 16, 18 respectively.
Is rotated. Power transistor Tr _u1 , T
The switching of r _v1 , Tr _w1 and Tr _u2 , Tr _v2 , Tr _w2 is performed in the order of (1) to (6) or (6) to (1) shown in Table 1, and the permanent magnet is in the forward direction or It can be rotated in the opposite direction.

[0016]

[Table 1]

Therefore, the electronic control unit 40 is
When the steering direction and the steering angle of the left and right rear wheels 16 and 18 are calculated, the power transistors Tr _u1 , Tr _v1 , Tr _w1 and T are provided so as to obtain the steering direction and the steering angle.
Switching between r _u2 , Tr _v2 , and Tr _w2 , which results in the left,
The right rear wheels 16 and 18 are rotated by the set angle in the set direction. The timing of this switching is adjusted based on the phase of the rotor coil with respect to the coil detected by the encoder.

As described above, in the brushless motor 34, among the power supply lines U, V, W, the power supply side power transistors Tr _u1 , Tr _v1 , Tr _w1 and the coils 50a, b, 52.
Since the two parts between a, b, 54a, b are provided in parallel, even if one of the power supply lines is disconnected, the other power supply line supplies current, and the left and right rear wheels 16 , 18
The left and right rear wheels 16 and 18 will not rotate or will not return while rotating.
The running stability of the vehicle is not impaired. Brushless motors can generate rotation by switching power transistors, and in addition to being more reliable than commutator motors that require contact between a commutator and a brush for rotation, further increase reliability. Can be done.

Two coils are provided for each phase of the brushless motor 34. Even if one coil is broken, the other coil generates a magnetic field to rotate the rotor. The right rear wheel 16, 18 can be rotated.

Further, the power transistor T on the power source side
r _u1 , Tr _v1 , Tr _w1 and coils 50a, b, 52a,
Between b, 54a, and b, current is supplied by two power supply lines, so that the power supply line can be made thin to facilitate the arrangement. In that case, when one of the power supply lines is broken, two currents flow in the other power supply line. For example, when the power supply line is broken, the left and right rear wheels 1
After returning 6, 18 to the neutral position where they are not rotated,
If the current supply to all the coils is cut off, a large amount of current will flow in the power supply line for an extremely short time, which is no problem.

Further, the power supply side power transistor Tr _u1 ,
Tr _v1 , Tr _w1 and coils 50a, b, 52a, b, 54
When a connector is provided between a and b, the power supply line U
It is desirable to provide one each for ₁ , V ₁ and W ₁ and power supply lines U ₂ , V ₂ and W _2, and in this case as well, in comparison with the case where current is supplied by one power supply line, the connector is provided. The flowing current is halved, and it becomes possible to use a small connector, and the effect of improving the vehicle mountability is obtained.

Further, in order to obtain each of the above effects, the power supply side power transistors Tr _u1 , T of the power supply lines U, V, W are provided.
r _v1 , Tr _w1 and coils 50a, b, 52a, b, 54
The two parts between a and b may be provided in parallel, the configuration of the brushless motor 34 may be hardly changed, and the above effects can be easily obtained while suppressing an increase in cost.

Another embodiment of the present invention is shown in FIG. In this embodiment, two coils 72a, 72b, 74a, 74b, 7 provided in each phase of the three-phase brushless motor 70 are provided.
One of 6a and 76b is connected to divide into two groups of coils, and the coils of each group are controlled by separate drivers 78 and 80, respectively.

One set of coils 72a, 74a, 76a
Are connected to the power source 82 by power source lines U, V, W, and ground cables 84, 86, 88 are connected to the power source lines U, V, W, respectively. The power source lines U, V, W are provided with power source side power transistors Tr _u1 , Tr _v1 , Tr _w1 , respectively, and the ground cables 84, 86, 88 are provided with ground side power transistors Tr _u2 , Tr _v2 , Tr _w2 , _{respectively. Are} provided, and these power transistors Tr _u1 , Tr _v1 , Tr _w1 and Tr
_u2 , Tr _v2 , and Tr _w2 form a driver 78.

The other driver 80 is also constructed in the same manner, and power source side power transistors Tr _u1 ′ and Tr provided on power source lines U ′, V ′ and W ′ connecting the coils 72 b, 74 b and 76 b and the power source 82, respectively. ground side power transistors Tr _u2 ′, Tr _v2 ′, T provided on _v1 ′, Tr _w1 ′ and ground cables 90, 92, 94, respectively.
r _w2 ′. The power supply lines U, V, W and the power supply lines U ', V', W'are collectively referred to as a power supply 82.
However, these two power supply lines combined are independent of each other.

In the present embodiment, the power transistor Tr
_u1 , Tr _v1 , Tr _w1 , Tr _u2 , Tr _v2 , Tr _w2 , T
r _u1 ′, Tr _v1 ′, Tr _w1 ′, Tr _u2 ′, Tr _v2 ′, T
The switching of r _w2 ′ is performed in the order of (1) to (6) or (6) to (1) in Table 2.

[0027]

[Table 2]

Since two sets of drivers are provided in this embodiment, in addition to the effects of the above-described embodiment, even if one of the power transistors of one driver 78 fails, the permanent magnet can be rotated. At the same time, the amount of current flowing through one power transistor can be small, and the effect that it can be configured at low cost can be obtained. The rated current of the power transistor is proportional to the cost, and if the supplied current is small, the rated current can be reduced and the cost can be reduced.

In this embodiment, two sets of coils, drivers, and power supply lines are provided, but one driving force generating member (permanent magnet) is provided, and two driving force generating members are provided as in the conventional case. The motor can be made compact and inexpensive as compared with the case where it is provided.

Further, the power supply lines U, V, W and U ', V',
When a relay or a fuse is provided on the power supply lines respectively connecting W'and the power supply 82, it is desirable to provide an independent relay or fuse.

Further, also in this embodiment, a connector may be provided in a portion between the power source side power transistor of the power source line and the coil. In that case, the current flowing through the connector is as small as one coil and small. A connector can be used, and even if any of the connectors fails, the connector provided for the coil that plays the same role as the coil provided with the connector is normal and the rotation can be obtained without any trouble.

In the embodiment shown in FIGS. 1 and 2, the two parts of the power supply line between the power supply side power transistor and the coil are provided in parallel, but depending on the position of the power supply side power transistor. May be provided in two parts in parallel with the power source side, or both may be provided in parallel.

In each of the above embodiments, two coils are provided for each phase of the brushless motor, but one coil may be provided, or three or more coils may be provided.

Further, although the rotation amount of the brushless motor is detected by the encoder in the above embodiment, it may be detected by another type of sensor such as a Hall element sensor.

Furthermore, the present invention can be applied to various electric motors other than brushless motors such as brushless motors used in devices other than the rear wheel steering device, commutator motors, stepping motors, and linear motors.

In addition, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a brushless motor for a drive wheel steering apparatus that is an embodiment of the present invention.

FIG. 2 is a diagram schematically showing an automobile equipped with the drive wheel steering device.

FIG. 3 is a circuit diagram of a brushless motor for a drive wheel steering apparatus that is another embodiment of the present invention.

[Explanation of symbols]

34 brushless motor 42 driver 50a, 50b, 52a, 52b, 54a, 54b coil 56 power supply U, V, W, U ₁ , V ₁ , W ₁ , U ₂ , V ₂ , W ₂ power supply line 70 brushless motor 72a, 72b , 74a, 74b, 76a, 76b Coil 78, 80 Driver 82 Power supply U, V, W, U ', V', W'Power supply line

Claims (1)

[Claims] 1. A coil that generates a magnetic field by supplying an electric current, and a driving force generation member that is provided so as to be movable relative to the coil and that generates a driving force between the coil and the coil when the magnetic field is generated. The coil includes a power supply that supplies a current to the coil, a power supply line that connects the coil and the power supply, and a controller that is provided on the power supply line and that controls the supply of the current from the power supply to the coil. In the electric motor in which either one of the drive force generating member and the driving force generating member moves, at least the longer one of the portion of the power supply line between the power source and the controller and the portion between the controller and the coil. An electric motor characterized in that a plurality of parts are provided in parallel.