KR0150829B1 - Steering torque sensor for power-assist vehicle steering - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering torque sensor of an electric steering apparatus, and in particular, a torsion bar for generating torque, a means for detecting only a torsion angle, a linear displacement mechanism, and the like, and a ring with a stain gauge is applied to the steering apparatus. By installing the thrust torque by measuring the thrust torque, it is possible to easily detect the steering torque without a separate torque detection device, so that the number of parts can be reduced, the device can be downsized, and maintenance and installation are easy.

Description

Steering Torque Sensor of Electric Power Steering System

1 is a configuration diagram of a conventional steering torque sensor.

2 is an enlarged cross-sectional view of a steering torque sensor of the present invention.

Figure 3 is an enlarged perspective view of the main portion of the present invention.

4 is a schematic diagram of the installation and use of the present invention.

* Explanation of symbols for main parts of the drawings

1: rack 2: pinion gear

2a: Steering Shaft 3: Strain Gage

4: ring 5: bearing

6: nut 7: nut cover

8: electronic control unit 9: housing

20: electric motor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering torque sensor of an electric steering apparatus, and in particular, a torsion bar for generating torque, a means for detecting only a torsion angle, a linear displacement mechanism device, and the like, and a strain gage ring is attached to the steering apparatus. The present invention relates to a steering torque sensor of an electric steering apparatus that measures steering torque by installing thrust and detects steering torque in a simple structure without a separate torque detection device.

In general, a steering torque detection device is installed and used in a vehicle electric steering device to detect steering torque.

Looking at the steering torque sensor used as the steering torque detection device of the conventional steering device used for this purpose, as shown in Figure 1 by amplifying the torsion bar 11 and the rotation displacement to change the steering torque to rotation displacement It is composed of a combination of a mechanism part 51 for converting the linear displacement and a linear displacement sensor portion 52 for measuring the linear displacement. Patent publication).

Therefore, in the conventional steering torque sensor as described above, the torsion bar 11 generates a torsion when the ground resistance between the tire and the ground is large.

The torsion generated at this time generates the linear movement of the slider by the free ring gear of the planetary gear and generates the corresponding voltage by measuring the linear displacement moved by the potentiometer, which is a linear displacement sensor.

The reason why the planetary gear mechanism is used is not only to amplify the torsion angle of the minute torsion bar 11 but also to detect when a torsion occurs.

In other words, the torsion bar's torsion does not occur even if the steering wheel is turned when the tire's grounding resistance is small.

Looking at the conventional torque measurement process as described above,

The torque is measured by detecting the V (voltage) by the X (slider displacement) -linear displacement sensor handled by the Q2 (detection and amplification) -linear displacement mechanism by the handle input-Q1 generation (torsion bar) -plane shift.

Therefore, the conventional steering torque sensor as described above requires a means for detecting only the torsion angle of the torsion bar (the planetary gear and the slip ring), and since the torsion angle is mostly changed to the linear displacement, a linear displacement mechanism part is required. Therefore, the number of parts required is large, the torque sensing part is enlarged, and maintenance and mounting are difficult.

In addition, there must be a torsion bar that generates a torque, there is a problem that the device is large.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and an object of the present invention is to remove a torsion bar for generating torque, a means for detecting only a torsion angle, a linear displacement mechanism device, and the like and a strain gage ring. It is to provide a steering torque sensor that can easily detect the steering torque without the need of a separate torque detection device by measuring the steering torque by measuring the thrust installed in the steering device.

The present invention for achieving the above object is connected to the steering wheel, the steering shaft rotates together, the pinion gear installed at the end of the steering shaft, and meshes with the pinion gear to convert the rotational motion of the pinion gear into a linear motion An electric power steering apparatus having a rack, comprising: a pinion gear and a rack whose twist is formed so that a thrust as an axial force is generated when the steering shaft is rotated, and detecting a thrust transmitted through the steering shaft A plurality of strain gauges adjacent to a bearing on which the steering shaft is supported to generate an electrical signal, and an electronic control unit connected to the strain gauge to receive the electrical signal of the strain gauge and determine a rotation direction and torque of the steering shaft. It is a configuration characterized by having a.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. Figure 2 is a cross-sectional view showing the structure of the steering torque sensor of the present invention, Figure 3 is an enlarged perspective view of the ring portion is attached to the strain gauge according to the present invention, Figure 4 is a schematic diagram showing the installation and use of the present invention.

As shown therein, the steering apparatus to which the present invention is applied is provided with a pinion gear 2 at the tip of the steering shaft 2a which is rotated together with the steering wheel 10, and the pinion gear 2 has a pinion gear ( The rack (1) which engages with 2) and performs linear motion is installed. That is, in the steering apparatus, the rotational movement of the steering wheel 10 is changed into a horizontal linear motion through the rack 1 and the pinion gear 2. To this end, the steering shaft 2a is rotatably installed at the end thereof in the housing 9, and the rack 1 is installed to be slidable in the transverse direction. Here, a bearing 5 is installed between the housing 9 and the end of the steering shaft 2a so as to be able to pivotally support the steering shaft 2a.

On the other hand, the rack (1) and the pinion (2) is composed of a helical gear that is smooth transmission and can transmit a large force and at the same time generates axial thrust. That is, since the helical gear has a tooth-twisted structure, when the pinion gear 2 installed on the steering shaft 2a is rotated, thrust, which is an axial force, is generated, and this thrust is a rotational direction of the gear. When this changes, the direction of action changes.

The present invention senses the torque applied to the steering shaft 2a and the rotational direction of the steering shaft 2a using the helical gear characteristics. For this configuration, the bearing 5 on which the steering shaft 2a is supported is provided with a strain gauge 3 having a strain gauge 3 for receiving an input and generating an electrical signal so as to detect the thrust of the steering shaft 2a. This is installed.

Then, the ring 4 is provided at the upper and lower portions of the bearing 5, respectively, so that the change in the thrust applied to the steering shaft 2a can be detected through the electrical signal of the strain gauge 3. At this time, the ring 4 is installed to support the outer ring of the bearing 5 so as not to affect the rotation of the steering shaft 2a. In addition, the end of the steering shaft (2a) and the housing (9) is provided with a nut (6) and a nut cover (7) to minimize the effect of the backlash generated during operation of the steering shaft (2a) and achieve a stable coupling state .

In addition, the steering torque sensor according to the present invention is the electronic connected to them so as to control the operation of the electric motor 20 provided on one side of the steering apparatus based on the electrical signal of the strain gauge (3) installed in the ring (4) The control unit 8 is provided. Here, the electric motor 20 is sea-operated to control the electronic control unit 8, and assists the operation of the steering device.

The following describes the effects of the embodiment of the present invention.

When the steering wheel 10 is rotated to the left and right, the pinion gear 2 and the rack 1 are interlocked together, and thrust is generated in the steering shaft 2a in the up and down directions, so that the upper and lower parts of the bearing 5 Pressure strain is applied to the strain gauges 3 of the rings 4 respectively installed. At this time, the thrust of the force is changed according to the rotation direction of the steering shaft (2a). That is, this force is applied only in one direction when the steering shaft (2a) is rotated in one direction, it is alternately applied to only one of the upper or lower ring (4) in accordance with the rotation direction of the steering shaft (2a). . Accordingly, the electronic control unit 8 determines whether the thrust is applied to the upper ring 4 or the lower ring 4 to detect the rotational direction and the steering torque of the steering shaft 2a and transmit the electric force. The motor 20 can be controlled.

Herein, the electronic control unit 8 has a circuit for amplifying a small voltage generated when the strain gauge 3 is compressed, and the electric motor 20 can be driven with an appropriate force according to the vehicle speed and steering torque. The control signal is controlled.

As such, since the steering torque sensor according to the present invention is easily implemented through the strain gauge 3 and the electronic control unit 8, unlike the conventional torque sensor, the number of components is significantly reduced and the torsion bar is not necessary, Some parts of the steering system can be changed for easy implementation.

As described in detail above, the steering torque sensor according to the present invention excludes a torsion bar for generating torque, a means for detecting only a torsion angle, a linear displacement mechanism, and the like, and a strain gauge 3 on the steering shaft 2a. By installing the ring 4 with), the torque and the rotation direction can be measured. Therefore, the number of parts is greatly reduced, so that the steering apparatus can be miniaturized, and maintenance and mounting can be easily performed, thereby providing convenience in use.

Claims (1)

In an electric power steering apparatus having a steering shaft connected to a steering wheel and rotated together, a pinion gear installed at an end of the steering shaft, and a rack engaged with the pinion gear to convert a rotational movement of the pinion gear into a linear movement. Pinion gears and racks whose shape is twisted so that thrust in the axial direction is generated when the steering shaft is rotated, and the steering shaft is supported to generate an electrical signal by detecting the thrust transmitted through the steering shaft. And a plurality of strain gauges adjacent to the bearings, and an electronic control unit connected to the strain gauges to receive the electrical signals of the strain gauges and determine the rotation direction and the torque of the steering shaft. Steering torque sensor.