KR20030090360A - Moter driven power steering system using linear motor - Google Patents

Abstract

PURPOSE: A motor driven power steering system using a linear motor is provided to smoothly perform steering by controlling the linear motor through signals detected from a vehicle speed sensor and a torque sensor. CONSTITUTION: A motor driven power steering system using a linear motor includes a steering shaft(120); a torque sensor(400) measuring the torque of the steering shaft; a vehicle speed sensor(500) measuring the speed of a vehicle; a steering linkage(200) having a rack shaft(240) to form a rack gear part(240a) engaging with a pinion shaft(130) and performing steering by transmitting rotary force, transmitted through the steering shaft, to right and left wheels(110,110'); a permanent magnet part(220) in which plural N-poles and S-poles are alternately disposed to the outer peripheral surface of the rack shaft; an armature coil part(230) in which plural armature coils, corresponding to the permanent magnet part, are combined to a cover(210) of the steering linkage; and an electronic control unit(300) applying an electric current to the armature coil part, based on signals detected from the vehicle speed sensor and the torque sensor, and taking charge of the whole control of the vehicle. A steering wheel(100) is mounted to the upper end of the steering shaft and the pinion shaft is connected to the lower end of the steering shaft. In the steering shaft, plural universal joints(125) are combined between the steering wheel and the pinion shaft, to transmit rotation of the steering wheel to the right and left wheels. The steering linkage is extended to the right and left direction of the vehicle.

Description

Electric Power Steering System Using Linear Motors {MOTER DRIVEN POWER STEERING SYSTEM USING LINEAR MOTOR}

The present invention relates to an electric power steering apparatus using a linear motor, and more particularly, to an electric power steering apparatus using a linear motor for smooth steering by controlling a linear motor based on signals detected by a vehicle speed sensor and a torque sensor. .

In general, a power steering system of a vehicle is for a driver to steer the vehicle more easily and accurately, and in particular, a device capable of steering the vehicle with low force during low speed driving, such as during parking. The power steering device of such a vehicle includes a mechanical device and a hydraulic device for operating a steering wheel using a hydraulic pump. Recently, hydraulic power steering devices are increasingly used due to the convenience of operation. This hydraulic power steering device is a hydraulic pump for sucking the oil in the oil tank, and since each hydraulic line is installed, the mounting and maintainability is low, the load on the engine is disadvantageous in terms of fuel efficiency. As a device for compensating for this, there is a motor-driven power steering system that assists steering by using electricity as a power source, which will be described with reference to FIG. 1 for better understanding of the present invention.

1 is a view schematically showing a general structure of a conventional electric power steering apparatus.

As shown in FIG. 1, a configuration of a conventional electric power steering apparatus includes a steering shaft train including a plurality of shafts interconnected by a universal joint 3. A steering wheel 1 is attached to the upper end of the steering shaft, and a pinion shaft 4 is attached to the lower end of the steering shaft 2, and one end of the pinion shaft 4 is attached to the rack. Mesh with rack; Thus, when the rack 5 moves reciprocally along its longitudinal axis, the steering shaft 2 rotates in its entirety in the direction along the direction of movement of the rack 5 (ie right or left in the figure). The pinion shaft 6 to which the worm wheel 7 is fixedly attached is engaged with the rack 5 at its other end. The worm wheel 7 is engaged with the worm 8 and the worm 8 is then coupled to a reversible motor 10 that generates steering assistance torque through an interposed electromagnetic clutch 9.

In operation, when the reversible motor 10 is electrically activated with the electromagnetic clutch 9 coupled, the worm 8 rotates in the direction of rotation of the worm wheel 7 and then the pinion shaft 6 responds. Direction, which causes the rack 5 to move in the left and right directions in the drawing. Thus, the pinion shaft 4 rotates in the corresponding direction. In this way, the output torque produced by the reversible motor 10 (hereinafter referred to as 'auxiliary torque') is transmitted to the handle 1 via the electromagnetic clutch 9, the rack / warm gear train and the steering shaft 2. Delivered, thereby facilitating the authoring of the steering wheel 1.

Control of the reversible motor 10 for generating an auxiliary torque transmitted to the steering shaft 2 and then to the steering shaft 1 is executed by an electronic control unit (ECU) 20. The electronic control unit 20 receives input signals such as a steering angle sensor 13 for detecting a rotation angle of the handle 1, a torque sensor 12 for measuring steering torque, and a vehicle speed sensor 11 for measuring a vehicle speed. Based on the control of the reversible motor 10.

However, in the conventional electric power steering apparatus configured as described above, the power transmission efficiency is reduced by the mechanical contact between the worm 8, the pinion shaft 6 and the rack 5, and the steering is affected by the inertia motor 10 inertia. While the feeling is lowered, there is a risk that the operation sound of the reversible motor 10 is bulky and flows into the room, and when an abnormality occurs in each component, there is a problem that may cause a great danger.

In addition, the conventional electric steering power unit is difficult to efficiently use the engine room due to the mounting of the reversible motor 10, the electromagnetic clutch 9, the worm wheel 7, the worm 8 and the pinion shaft 6 and the like. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an electric power steering apparatus using a linear motor having a simple structure, low manufacturing cost, and high operational reliability by mounting a linear motor. .

In order to achieve the above object, the electric power steering apparatus using the linear motor of the present invention is equipped with a steering wheel at the top and a pinion shaft at the bottom, and a plurality of universal joints are coupled between the steering wheel and the pinion shaft. A steering shaft for transmitting rotation of the steering wheel to left and right wheels; A torque sensor for measuring torque of the steering shaft; A vehicle speed sensor measuring a speed of the vehicle; A part of which is built into the cover, extends in the left and right directions of the vehicle, and has a rack shaft formed with a rack gear part engaged with the pinion shaft at one side to transmit the rotational force transmitted through the steering shaft to the left and right wheels. A steering linkage for steering; A permanent magnet part having a plurality of N pole and S pole permanent magnets alternately disposed on an outer circumferential surface of the rack shaft; An armature coil part having a plurality of armature coils coupled to the permanent magnet part on a cover of the steering linkage; And an electronic control unit that applies magnetization by applying current to the armature coil unit based on the signals detected by the vehicle speed sensor and the torque sensor and is responsible for overall control of the vehicle.

In addition, the electric power steering apparatus using the linear motor of the present invention is equipped with a steering wheel at the top and the pinion shaft is connected to the bottom, a plurality of universal joints are coupled between the steering wheel and the pinion shaft of the steering wheel A steering shaft for transmitting rotation to the left and right wheels; A torque sensor for measuring torque of the steering shaft; A vehicle speed sensor measuring a speed of the vehicle; The cross section is formed in a '凸' shape, the rack gear portion is engaged with the pinion shaft is formed on the upper surface, and the permanent magnet portion is provided with a plurality of N pole and S pole permanent magnets alternately arranged in the longitudinal direction on the bottom surface A steering linkage having a rack shaft extending in the left and right directions of the steering link to transmit the rotational force transmitted through the steering shaft to the left and right wheels for steering; An armature coil part having a cross-sectional shape of '凹' shape and fixedly installed in place of the vehicle body, inserted into the air by forming a gap having a predetermined thickness with the permanent magnet part, and an armature coil formed on each side wall; And an electronic control unit that applies magnetization by applying current to the armature coil unit based on the signals detected by the vehicle speed sensor and the torque sensor and is responsible for overall control of the vehicle.

1 is a view schematically showing a general structure of a conventional electric power steering device,

2 is a view schematically showing an electric power steering apparatus using a linear motor according to an embodiment of the present invention;

3 is a partially cutaway perspective view showing an important part of an electric power device using a linear motor according to another embodiment of the present invention.

*** Explanation of symbols on main parts of drawing ***

100: steering wheel, 110,110 ': left and right wheels,

120: steering shaft, 125: universal joint,

130,730: pinion shaft, 200: steering linkage,

210: cover, 220,800: permanent magnet part,

220a, 220b, 800a, 800b: N pole, S pole permanent magnet,

230,900: armature coil, 230a, 900a: armature coil,

240,600: rack shaft, 240a: rack gear part,

250: tie rod, 260: knuckle arm,

300: electronic control unit, 400: torque sensor,

500: vehicle speed sensor

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. This embodiment is not intended to limit the scope of the invention, but is presented by way of example only. In addition, the linear motor in the present invention is a structure that generates a thrust between the mover and the stator, which typically face in a straight line, in the embodiment of the present invention. The mover and the stator correspond to the permanent magnet part and the armature coil part, which will be described later.

2 is a view schematically showing an electric power steering apparatus using a linear motor according to an embodiment of the present invention.

As shown in FIG. 2, the electric power steering apparatus according to the present invention includes a steering shaft 120 that transmits rotation of the steering wheel 100 to left and right wheels 110 and 110 ′, and a steering shaft. The steering linkage 200 for steering by transmitting the rotational force transmitted through the 120 to the left and right wheels 110 and 110 ', and the permanent magnet part mounted in the cover 210 of the steering linkage 200. 220, an armature coil unit 230 installed on the cover 210 corresponding to the permanent magnet unit 220, and electrons for providing auxiliary steering force by applying current to the armature coil unit 230 during steering. It is configured to include a control unit 300.

In the above-described configuration, the steering wheel 100 is attached to the upper end of the steering shaft 120 and the pinion shaft 130 is attached to the lower end of the steering shaft 120, and are connected to each other by the plurality of universal joints 125.

The steering linkage 200 transmits the steering force transmitted from the steering shaft 120 to the left and right wheels 110 and 110 'through the pinion shaft 130 attached to the lower end of the steering shaft 120. In the cover 210 of the linkage 200, a rack gear part 240a is formed at one side thereof and engaged with the pinion shaft 130, and a rack shaft 240 extending in the left and right directions of the vehicle is provided. In addition, the outer circumferential surface of the rack shaft 240 is provided with a permanent magnet portion 220 in which a plurality of N-pole and S-pole permanent magnets 220a and 220b alternately arranged. In addition, an armature coil unit 230 having a plurality of armature coils 230a having a cylindrical shape is installed on the cover 210 to correspond to the permanent magnet unit 220.

The electronic control unit 300 magnetizes the armature coil unit 230 based on input signals such as a torque sensor 400 for measuring torque of the steering shaft 120 and a vehicle speed sensor 500 for measuring a vehicle speed, thereby assisting. Will generate steering power.

The armature coil unit 230 installed as described above is magnetized by various driving information of the vehicle, for example, the vehicle speed and torque of the steering shaft 120, and at this time, between the permanent magnet unit 220 and the armature coil unit 230. It has a structure that pushes the rack shaft 240 to the left or right based on the attraction and repulsive force generated.

Then, the electronic control unit 300 applies a control signal (for example, a current signal, etc.) to the armature coil unit 230 and magnetizes the control to push the permanent magnet unit 220 to the left or the right side, that is, linearly. The technique for controlling the motor is well known and thus a detailed description thereof will be omitted.

Reference numerals 250 and 260 denote tie rods and knuckle arms, respectively, and the tie rods 250 are coupled to both sides of the rack shaft 240, and the tie rods 250 are steered, respectively. It is connected to the knuckle arm 260 which supports the left and right wheels 110 and 110 'as wheels.

3 is a partially cutaway perspective view showing an important part of an electric power steering apparatus using a linear motor according to another embodiment of the present invention.

As shown in FIG. 3, the electric power steering apparatus using the linear motor according to another embodiment of the present invention has all configurations except the structures of the rack shaft, the armature coil unit, and the permanent magnet unit shown in the above-described embodiment of the present invention. Is the same, so a detailed description thereof will be referred to an embodiment of the present invention.

The rack shaft 600 of the electric power steering apparatus according to another embodiment of the present invention is formed of a rectangular flat bar, and a rack gear part 610 is formed on a portion of the upper surface thereof to be engaged with the pinion shaft 730. Permanent magnet portion 800 in which a plurality of N and S pole permanent magnets 800a and 800b are alternately arranged in the longitudinal direction is provided. On the other hand, the N pole and S pole permanent magnet (800a) (800b) is preferably made of a rectangular shape.

The armature coil part 900 is provided to be fixedly installed in the vehicle body and to form a gap having a predetermined thickness with the permanent magnet part 800. The armature coils 900a are formed on both side walls of the armature coil part 900. ) Is formed.

Both ends of the rack shaft 600 are connected to tie rods and knuckle arms, respectively, as in one embodiment of the present invention.

On the other hand, it is preferable that the cross section of the armature coil part 900 and the rack shaft 600 is formed in an uneven | corrugated shape, respectively.

By combining the armature coil part 900 and the permanent magnet part 800 having an uneven shape as described above, the armature coil part 900 is configured to provide various driving information of the vehicle, for example, a vehicle speed and a steering shaft (FIG. 2). Magnetized by the control of the electronic control unit (see FIG. 2) based on a signal such as torque, and the like, based on the attraction force and repulsive force generated between the permanent magnet part 800 and the armature coil part 900. It has a structure for pushing the shaft 600 to the left or right.

According to the electric power steering apparatus using the linear motor of the present invention described above, it has a simple structure and can provide the auxiliary steering force by using the attraction force and repulsive force of the magnet.

In addition, in another embodiment of the present invention, the permanent magnet portion 800 and the armature coil portion 900 can be installed in the entire rack shaft 600, so that their size is increased, further increase the thrust for power assistance It becomes possible.

Although a preferred embodiment of the electric power steering apparatus using the linear motor according to the present invention has been described above, the present invention is not limited to this, but the scope of the claims and the detailed description of the invention and the accompanying drawings in various ways. It is possible to carry out modification and this also belongs to the present invention.

According to the electric power steering apparatus using the linear motor of the present invention as described above, the armature coil part is magnetized by the control of the electronic control unit based on the signals detected by the vehicle speed sensor and the torque sensor, and the permanent magnet part and the armature nose. By pushing the rack shaft to the left or right on the basis of manpower and repulsive forces generated between the parts, steering is smooth, there is no mechanical noise, and the overall weight of the power steering is reduced, which in turn reduces fuel economy. In addition, the manufacturing cost of the power steering device is reduced, there is an advantage that the environmental pollution is prevented to improve the commerciality.

In addition, in the electric power steering apparatus using the linear motor of the present invention, the rack shaft is formed on the upper portion of the rack shaft and a plurality of N and S pole permanent magnets in the longitudinal direction alternately arranged in the longitudinal direction on the bottom shaft shaft and The permanent magnet part and the armature coil part are large in size by being fixedly installed in the vehicle body and made of an armature coil part having armature coils formed on both side walls so as to form a gap having a predetermined thickness with the permanent magnet part. As a result, there is an advantage that can further increase the thrust for power assistance.

Claims (2)

A steering shaft mounted at an upper end and a pinion shaft connected at a lower end thereof, and a plurality of universal joints coupled between the steering wheel and the pinion shaft to transmit rotation of the steering wheel to left and right wheels; A torque sensor for measuring torque of the steering shaft; A vehicle speed sensor measuring a speed of the vehicle; A part of which is built into the cover, extends in the left and right directions of the vehicle, and has a rack shaft formed with a rack gear part engaged with the pinion shaft at one side to transmit the rotational force transmitted through the steering shaft to the left and right wheels. A steering linkage for steering; A permanent magnet part having a plurality of N pole and S pole permanent magnets alternately disposed on an outer circumferential surface of the rack shaft; An armature coil part having a plurality of armature coils coupled to the permanent magnet part on a cover of the steering linkage; And An electric power steering apparatus using a linear motor comprising an electronic control unit which applies a current to the armature coil unit and magnetizes it based on the signals detected by the vehicle speed sensor and the torque sensor and controls the overall control of the vehicle. A steering shaft mounted at an upper end and a pinion shaft connected at a lower end thereof, and a plurality of universal joints coupled between the steering wheel and the pinion shaft to transmit rotation of the steering wheel to left and right wheels; A torque sensor for measuring torque of the steering shaft; A vehicle speed sensor measuring a speed of the vehicle; The cross section is formed in a '凸' shape, the rack gear portion is engaged with the pinion shaft is formed on the upper surface, and the permanent magnet portion is provided with a plurality of N pole and S pole permanent magnets alternately arranged in the longitudinal direction on the bottom surface A steering linkage having a rack shaft extending in the left and right directions of the steering link to transmit the rotational force transmitted through the steering shaft to the left and right wheels for steering; An armature coil part having a cross-sectional shape of '凹' shape and fixedly installed in place of the vehicle body, inserted into the air by forming a gap having a predetermined thickness with the permanent magnet part, and an armature coil formed on each side wall; And An electric power steering apparatus using a linear motor comprising an electronic control unit which applies a current to the armature coil unit and magnetizes it based on the signals detected by the vehicle speed sensor and the torque sensor and controls the overall control of the vehicle.