WO2011062431A2

WO2011062431A2 - Apparatus for detecting steering torque and steering angle and steering system having the same

Info

Publication number: WO2011062431A2
Application number: PCT/KR2010/008165
Authority: WO
Inventors: Minchul Kang
Original assignee: Lg Innotek Co., Ltd.
Priority date: 2009-11-20
Filing date: 2010-11-18
Publication date: 2011-05-26
Also published as: KR101650457B1; KR20110055849A; WO2011062431A3

Abstract

Disclosed herein is a steering torque and steering angle measurement apparatus, the present invention including a stator fixed to an output shaft, a magnet disposed at the inner part of the stator and being fixed to an input shaft, a torque sensing part measuring a steering torque by sensing a magnetic field produced between the stator and the magnet, and a steering angle generation part outputting an index length (a length of time taken to circulate 360°) of the output shaft, thereby shortening the number of components, simplifying a manufacturing process and saving a manufacturing cost.

Description

APPARATUS FOR DETECTING STEERING TORQUE AND STEERING ANGLE AND STEERING SYSTEM HAVING THE SAME

The present invention relates to an apparatus for measuring a steering torque and a steering angle employed in a vehicle steering system.

In general, an automotive power steering system is an assistant operating-force providing system configured to smoothly operate a steering handle at the time of great friction resistance applied by a steering wheel leading to a large operating-force for steering a steering handle. Size of the assistant operating-force assisting a steering of the steering handle may be determined by measuring torque applied to a torsion bar when steering a steering handle.

As an apparatus measuring torque of the steering handle, a torque measurement apparatus of several types of methodologies have been developed and used, but a low-priced magnetic field method having a fewer numbers of components is mainly employed.

The steering angle measurement apparatus (module) includes a steering angle sensor, and this angle sensor measures a steering degree of the steering handle needed for control of an on-driving vehicle.

Also, the torque measurement apparatus (module) is mounted with a torque sensor, and the torque sensor measures torque applied to a torsion bar to smoothly manipulate a steering handle.

The overlaid angle sensor and torque sensor have separately modularized together with other composite members within an angle torque sensor assembly, that is, configured as an angle sensor module and a torque sensor module.

Conventionally, a torque sensor and an angle sensor for detecting the aforementioned steering torque and steering angle, respectively, are separately installed. Thus, a conventional torque measurement apparatus has a problem in that a component number increases and an installation process is complicated, leading to increase in manufacturing cost. Especially, the angle sensor has disadvantages of high manufacturing cost and cumbersome installation.

An object of the present invention is to provide an apparatus for detecting a steering torque and steering angle and a steering system having the same (hereinafter referred to as "steering torque and steering angle measurement apparatus and steering system having the same) such that a steering torque and steering angle measurement function may be configured in one assembly to reduce the number of components, simplify a manufacturing process and save a manufacturing cost.

The technical challenge to be achieved by the invention is not limited to the aforementioned, and it would be appreciated by those skilled in the art that other technical challenges can be understood from the following recitation.

A steering torque and steering angle measurement apparatus according to one embodiment includes a stator fixed to an output shaft, a magnet disposed at an inner part of the stator and being fixed to an input shaft, a torque sensing part measuring a steering torque by sensing a magnetic field produced between the stator and the magnet, and a steering angle generation part generating a steering angle signal by producing a signal whenever the output shaft rotates 360˚as well as outputting an index length (a length of time taken to circulate 360˚) of the output shaft.

The torque sensing part may include a collector installed inside a case to concentrate a magnetic field formed between the stator and the magnet, and a torque sensor sensing the magnetic field concentrated at the collector.

The steering angle signal generation part may include one magnet fixed to the output shaft, and a hall switch generating an ON signal when positioned to face said one magnet.

The vehicle-purpose steering system according to one embodiment of the present invention includes an input shaft connected to a steering handle, an output shaft connected to a steering wheel and connected to the input shaft by an intermediary of a torsion bar, a magnet disposed at the inner part of the stator and fixed to the input shaft, a torque sensing part measuring a steering torque by sensing a magnetic field produced between the stator and the magnet, and a steering angle generation part generating a steering angle signal by producing an ON signal whenever the output shaft rotates 360˚and by outputting an index length (a length of time taken to circulate 360˚) of the output shaft.

A steering torque and a steering angle measurement apparatus according to the present invention have advantageous effects in that a steering angle generation part generates a steering angle signal by producing an ON signal whenever an output shaft rotates 360˚and by outputting an index length (a length of time taken to circulate 360˚) of the output shaft to detect an steering angle, thereby shortening the number of components, simplifying a manufacturing process and saving a manufacturing cost.

FIG. 1 is a construction diagram of a vehicle steering system according to one embodiment of the present invention;

FIG. 2 is a perspective view of a steering torque and steering angel measurement apparatus according to one embodiment of the present invention;

FIG. 3 is a side view of a steering torque and steering angel measurement apparatus according to one embodiment of the present invention;

FIG. 4 is a construction diagram of a steering angle signal generation part according to one embodiment of the present invention; and

FIG. 5 is a graph for describing an output of a hall switch for detection of an steering angle of a steering angle signal generation part according to one embodiment of the present invention.

Hereinafter, a preferred embodiment of the invention will be described in consideration of the annexed drawings. The size and shape of components shown in the drawings during this procedure may be exaggerated or simplified for the sake of description's clarity and conveniences. Also, specially defined terms in consideration of the construction and function of the present invention may be varied according to the intention and custom of users and operators. Such terms-related definition should be made based on recitations throughout the entire specification.

FIG. 1 is a construction diagram of a steering system according to one embodiment of the present invention.

A steering system according to one embodiment of the invention includes a steering handle 100, an input shaft 200 connected to this steering handle 100 for simultaneously rotating when the steering handle 100 is circulated, an output shaft 300 connected to the input shaft 200 by an intermediary using a torsion bar and connected to a steering wheel, and a steering torque and steering angle measurement apparatus 400 installed between the input shaft 200 and the output shaft 300 to sense a steering torque and a steering angle.

FIG. 2 is a perspective view of a steering torque and steering angel measurement apparatus according to one embodiment of the present invention, and FIG. 3 is a side view of a steering torque and steering angle measurement apparatus according to one embodiment of the present invention.

As illustrated in FIGS. 2 and 3, a steering torque and steering angle measurement apparatus according to one embodiment includes a case 10, a stator 20 disposed inside the case, and a magnet 30 disposed at the inner part of the stator 20.

The case 10 is comprised of a first case 11 and a second case 13 coupled to each other and having a space at their inner part.

The stator 20 includes a stator holder 22 disposed inside the second case 13 and fixed to an output shaft, and a plurality of stator teeth 21 coupled to an inner-rim surface of the stator holder 22.

The stator 22 should be formed of nonmagnetic material to prevent the occurrence of a magnetic flux leakage of the stator teeth 21 that concentrates magnetic flux, and should have a preset or more intensity so that the output shaft is inserted therein for fixture.

The magnet 30 may be disposed within the stator holder 22, and disposed at a certain gap from the stator teeth 21 mounted inside the stator holder 22 to face each other, and formed of a ring shape having a plurality of poles such that its polarity may alter with an equal interval in a circumferential direction.

Such a magnet 30 is fixed to the outer-rim surface of the magnet holder 32, and the magnet holder 32 is fixed to the input shaft 200.

Since the input shaft 200 and the output shaft 300 are connected by means of a torsion bar, and the output shaft 300 is connected to a steering wheel contacting into a road, a rotating angle of the input shaft 200 and the output shaft 300 is different when rotating the steering handle 100 by an external force. Therefore, a rotating angle of the magnet 30 and the stator 20 is also different.

An inner part of the case 10 has a torque sensing part sensing a steering torque. The torque sensing part includes a collector (not shown) and a torque sensor 40.

The collector is fixed to one side of the second case 13, disposed to face the stator 20, and the torque sensor 40 is disposed to face the collector.

The collector concentrates a magnetic field formed between the stator 20 and the magnet 30, and the torque sensor 40 measures a steering torque sensing a magnetic field concentrated at the collector.

The torque sensor 40 is fixed to a printed circuit board 70 mounted inside the case 10, so as to be electrically connected to the printed circuit board 70.

The inner part of the case 10 has a steering angle signal generation part producing an ON signal whenever the output shaft 300 circulates 360˚as well as outputting the index length (a length of time taken to be 360˚circulated) of the output shaft 300 for generation of steering angle signal.

The steering angle signal generation part, as shown in FIG. 3, includes a rotating member 51 fixed to the output shaft 300 to rotate simultaneously with the output shaft 300 and formed of nonmagnetic material of a cylindrical shape, one or more magnet 52 fixed to the outer-rim surface of the rotating member, and a hall switch producing an ON signal when placed to face the magnet 52.

The hall switch 60 may include a general hall sensor, a hall device and devices serving alike. Such a hall sensor 60 is electrically connected to the printed circuit board 70 of the torque sensor 40 fixing the torque sensor 40.

In a case the magnet 52 is fixed to the outer-rim surface of the rotating member 51 in unison, the hall switch 60 may be positioned to face the magnet 52 whenever the output shaft 300 circulates 360˚ so that the hall switch 60 produces an ON signal as illustrated in FIG. 5. And, the hall switch 60 outputs an index length (a length of time taken to be 360˚circulated) when the output shaft 300 circulates 360˚.

And, the magnet 52 is disposed at an equal interval in a case fixed at the outer-rim surface of the rotating member in one or more, and produces an ON signal each time the output shaft 300 rotates 180˚or 90˚.

The torque sensor 40 may be outputted as V/Deg [Voltage/Degree] value, and the angle indicates a twisting angle of the torsion bar, and at this time senses a voltage output proportional to the angular amount. Therefore, by integrating a twisting angle by the operation-force of a driver, a total shifted angular amount can be inferred. At this time, by outputting an index signal value each time of 360˚circulation of the output shaft produced from the hall switch 60 in addition to the obtained inferred angle amount as well as outputting an index length signal when the output shaft rotates 360˚, it is possible to compute an absolute angle rotating more than 360˚in the same direction or can be used in confirming a range of a calculated angle. For example, when an output signal of a hall switch is recorded as number 1, it can be inferred that a corresponding steering angle range resides in 360˚through 720˚.

While embodiments according to the present invention have been described above, these are only by way of example and it would be understood by those skilled in the art that any embodiment of various modifications and equivalents can be made thereto. Thus, the genuine technical scope of the present invention should be defined from the accompanying claims.

A steering torque and steering angle measurement apparatus and a steering system having the same have industrial applicability in that a steering angle generation part generates a steering angle signal by producing an ON signal whenever an output shaft rotates 360˚and by outputting an index length (a length of time taken to circulate 360˚) of the output shaft to detect an steering angle, thereby shortening the number of components, simplifying a manufacturing process and saving a manufacturing cost.

Claims

A steering torque and steering angle measurement apparatus, characterized by:

a stator fixed to an output shaft;

a magnet disposed at an inner part of the stator and being fixed to an input shaft;

a torque sensing part measuring a steering torque by sensing a magnetic field produced between the stator and the magnet; and

a steering angle generation part generating a steering angle signal by producing a signal whenever the output shaft rotates 360˚as well as outputting an index length (a length of time taken to circulate 360˚) of the output shaft.
The apparatus of claim 1, wherein the stator includes a stator holder disposed inside a second case and fixed to an output shaft, and a plurality of stator teeth coupled to an inner-rim surface of the stator holder.
The apparatus of claim 1, wherein the magnet is formed of a ring shape, and disposed such that its polarity alters with an equal interval in a circumferential direction.
The apparatus of claim 1, wherein the torque sensing part includes a collector installed inside the case to concentrate a magnetic field formed between the stator and the magnet, and a torque sensor sensing the magnetic field concentrated at the collector.
The apparatus of claim 3, wherein the steering angle signal generation part includes one or more magnets fixed to the output shaft, and a hall switch producing an ON signal when placed to face the magnet.
The steering torque and steering angle measurement apparatus of claim 5, wherein the magnet is formed of nonmagnetic material, and fixed to the outer surface of a support member fastened to the output shaft for a simultaneous rotation with said output shaft.
The apparatus of claim 5, wherein the hall sensor is electrically connected to a printed circuit board having the torque sensor installed.
A vehicle steering system, characterized by:

an input shaft connected to a steering handle;

an output shaft connected to a steering wheel and connected to the input shaft by an intermediary of a torsion bar;

a magnet disposed at an inner part of the stator and fixed to the input shaft;

a torque sensing part measuring a steering torque by sensing a magnetic field produced between the stator and the magnet; and

a steering angle generation part generating a steering angle signal by producing an ON signal whenever the output shaft rotates 360˚as well as outputting an index length (a length of time taken to circulate 360˚) of the output shaft.
The steering system of claim 8, wherein the stator includes a stator holder disposed inside a second case and fixed to an output shaft, and a plurality of stator teeth coupled to an inner-rim surface of the stator holder.
The steering system of claim 8, wherein the magnet is formed of a ring shape, and disposed such that its polarity alters with an equal interval in a circumferential direction.
The steering system of claim 8, wherein the torque sensing part includes a collector installed inside the case to concentrate a magnetic field formed between the stator and the magnet, and a torque sensor sensing the magnetic field concentrated at the collector.
The steering system of claim 8, wherein the steering angle signal generation part includes one or more magnets fixed to the output shaft, and a hall switch producing an ON signal when placed to face the magnet.
The steering system of claim 12, wherein said one magnet is formed of nonmagnetic material, and fixed to the outer surface of a support member fastened to the output shaft for a simultaneous rotation with said output shaft.
The steering system of claim 12, wherein the hall sensor is electrically connected to the printed circuit board having the torque sensor installed.