JPH07267111A - Steering torque detecting device - Google Patents

Abstract

PURPOSE:To detect the displacement due to the relative rotation of an input shaft an output shaft without direct contact with a slider in a steering sensor, simplify the constitution by reducing the number of parts, facilitate adjustment by obviating the need of taking a neutral point at the time of installation, and improve the reliability by decreasing the aged deterioration, abrasion and failure. CONSTITUTION:A non-contact type medium means 62 is disposed between a slider 64 interlocking with the operation of a ball 74 movably provided in a sensing groove 78 of an input shaft 28 and a steering sensor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering torque detecting device, and more particularly to a steering torque detecting device having a simple structure, facilitating adjustment at the time of mounting, and improving reliability.

[0002]

2. Description of the Related Art Some vehicles are equipped with an electric power steering device in order to reduce an operating force of a steering wheel, that is, a steering force of a steering wheel.

As shown in FIGS. 6 and 7, the electric power steering system 102 includes an input shaft 104 connected to a steering wheel (not shown) and an output shaft 106 connected to a steering gear (not shown). Is connected by an elastic body (torsion bar) 108 and is rotatably provided, and a steering sensor 110 for detecting a displacement amount due to relative rotation of the input shaft 104 and the output shaft 106 as steering torque is provided, and a signal from the steering sensor 110 is provided. A motor (motor) (not shown) driven based on the output shaft 1 is provided for driving the motor shaft 112 of the motor.
There is one that assists the operation force of the steering wheel by transmitting it to 06.

As shown in FIG. 7, the steering sensor 110 has a sensor main body 114 having a built-in potentiometer and the like, a sensor shaft 110 protruding from the sensor main body 114, and a sensor shaft 116 fixed to one end side thereof. It has a plate member (lever) 118 and a sensing portion 120 fixed to the other end of the plate member 118.

The sensing portion 120 is engaged with the circumferential groove 124 of the slider 122. The slider 122 is fitted onto the input shaft 104 so as to be movable in the axial direction.

The slider 122 interlocks with the operation of the ball 130 which moves in the sensing groove 128 formed in the groove forming portion 126 of the input shaft 104.

Further, such a steering torque detecting device is disclosed in, for example, Japanese Patent Laid-Open No. 63-192656. In the device described in this publication, when a steering torque is applied to the input shaft, the bearing fixed to one end of the pin rolls along the spiral groove formed on the slider, and by the cam action of the bearing and the spiral groove. By smoothly moving the slider up and down on the output shaft in the axial direction and electrically detecting the displacement with an electric detection device, the magnitude of the torque applied to the input shaft and the torque detection signal output in that direction can be detected. I will get it.

[0008]

However, in the conventional steering torque detecting device, a mechanical intermediary means between the slider and the steering sensor, that is, a link mechanism using a plate member (lever) or a strain gauge is used. Since this mechanism is provided, the number of parts is increased and the configuration is complicated, and adjustment is complicated because the neutral point is set during installation. There was an inconvenience that it decreased.

[0009]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention connects an input shaft connected to a steering wheel of a vehicle and an output shaft connected to a steering gear with an elastic body. And a ball that can be moved relative to the sensing groove formed on the input shaft, and a slider that can move in the axial direction of the input shaft in association with the movement of the ball is provided on the input shaft. In a steering torque detecting device provided with a steering sensor for detecting a displacement amount due to relative rotation between the input shaft and the output shaft by the operation of a slider, a non-contact type mediating means is provided between the slider and the steering sensor. Is characterized by.

[0010]

According to the structure of the present invention, the steering sensor detects the displacement amount due to the relative rotation between the input shaft and the output shaft without directly contacting the slider, so that the number of parts is reduced and the structure is simplified. Further, it is not necessary to set the neutral point at the time of mounting, the adjustment can be facilitated, and further, the secular change, wear and failure can be reduced to improve the reliability.

[0011]

Embodiments of the present invention will be described in detail and specifically with reference to the drawings. 1 to 5 show an embodiment of the present invention. In FIG. 5, 2 is a vehicle, 4 is a front wheel, 6 is a rear wheel, 8 is a steering wheel, 10 is a steering column, and 12 is a steering gear.

The steering column 10 has a steering shaft 14 connected to the steering wheel 8 and a joint shaft 16 connected to the steering gear 12.

The steering gear 12 is a joint shaft 1.
Left and right tie rods 1 by converting the rotational movement of 6 into linear movement
The front and rear wheels 4 are steered by reciprocally moving the wheels 8 and 18 through a knuckle arm (not shown).

The vehicle 2 is provided with an electric power steering device 20.

This electric power steering device 20 is
It assists the operating force of the steering wheel 8 and has a direct current electric motor (motor) 22, a steering sensor 24, and a control means 26.

Further, in the electric power steering apparatus 20, as shown in FIG. 1, an input shaft 28 connected to the steering wheel 8 via the steering shaft 14,
An output shaft 30 connected to the steering gear 12 via a joint shaft 16 and an elastic body 32 made of an elastic member such as a torsion bar that connects the input shaft 28 and the output shaft 30 are provided.

The input shaft 28 is covered by an upper housing 34. The output shaft 30 is covered by the lower housing 36. The upper housing 34 and the lower housing 36 are integrally connected by a connecting bolt 38.

The input shaft 28 is provided such that its end portion on the output shaft 30 side is slightly separated from the large diameter portion 40 of the end portion on the input shaft 28 side of the output shaft 30 and is held by the shaft support portion 42 of the upper housing 34. It is supported by the seal portion 44.

The output shaft 30 is rotatably supported by output bearings 46, 46 held by a lower housing 36.

On the input shaft 28, the input side mounting hole 4 is provided on the axis.
8 is formed. Further, an output side mounting hole 50 is formed on the axial center of the output shaft 30 at an end portion on the input shaft 28 side so as to correspond to the input side mounting hole 48. The elastic body 32 is installed in the input side mounting hole 48 and the output side mounting hole 50. The end portion of the elastic body 32 on the steering shaft 14 side is fixed to the input shaft 28 by a fixture (not shown).

A worm wheel 52 is mounted on the outer peripheral portion of the large diameter portion 40 of the output shaft 30. The worm wheel 52 includes a motor shaft 54 of the electric motor 22.
The worm gear 56 provided in the gear meshes.

The driving force of the electric motor 22 is decelerated by the worm wheel 52 and the worm gear 56 constituting the reduction mechanism 58 and transmitted to the output shaft 30 via a clutch mechanism (not shown) to operate the steering wheel 8. Is to assist.

The steering sensor 24 detects the operating force of the steering wheel 8 and its direction, and detects the displacement amount due to the relative rotation of the input shaft 28 and the output shaft 30,
This displacement amount is exchanged with a voltage signal and output to the control means 26.

This steering sensor 24 is shown in FIGS.
As shown in FIG. 3, it has a sensor main body 60 having a built-in potentiometer and the like, and a non-contact type mediating means 62.

Further, in the steering sensor 24, a slider 64 which is fitted onto the input shaft 28 so as to be axially movable is provided. The slider 64 has a circumferential groove 6
6 is formed.

A cross guide 70 is fixedly attached to the slider 64 by a C ring 68.

The cross guide 70 has a ball hole 72.
Are formed. In this ball hole 72, a ball 74
Is stored. In addition, this ball 74 corresponds to the input shaft 2
Spiral-shaped sensing groove 78 formed in the groove forming portion 76 of FIG.
Is movably engaged with.

A cover 80 is attached to the cross guide 70 via a disc spring 80 so as to cover the ball 74. A sensing spring (not shown) oriented in the axial direction of the input shaft 28 is provided between the end portion of the disc spring 80 and the worm wheel 52.

The non-contact type mediating means 62 includes the circumferential groove 6
6, and the first and second Hall elements 8 facing the magnet 84 and spaced apart by a predetermined distance and mounted in parallel to the sensor body 60 in the axial direction of the input shaft 28.
6-1 and 86-2 (main sensor and sub sensor).

In the steering sensor 24, if the steering wheel 8 is not operated, the input shaft 28
There is no twist between the output shaft 30 and the output shaft 30, and thus no displacement occurs, so that the ball 74 does not move along the sensing groove 78, and therefore the slider 64 does not move in the axial direction of the input shaft 28. As a result, the neutral state is established, and the sensor body 60 detects the displacement amount between the input shaft 28 and the output shaft 30 as zero.

On the other hand, in the steering sensor 24, the input shaft 28 is operated by operating the steering wheel 8.
When a twist occurs between the output shaft 30 and the output shaft 30, the ball 74 moves along the sensing groove 78, the slider 64 moves in the axial direction of the input shaft 28 along with the ball 74, and the magnet mounted in the circumferential groove 66. When 84 moves, the magnetic flux increasing strength around the first and second Hall elements 86-1 and 86-2 changes,
The sensor main body 60 detects the main course of the magnetic strength as the displacement amount between the input shaft 28 and the output shaft 30.

The sensor body 60 of the steering sensor 24 outputs a voltage according to the displacement amount to the control means 26.

As shown in FIG. 5, the control means 26 includes
The steering sensor 24, an ignition coil 88 for detecting the engine speed, and a vehicle speed sensor 9 provided on, for example, a speedometer (not shown) for detecting the vehicle speed.
0, the generator 92 and the battery 94 are connected to detect the generated voltage.

The control means 26 is engaged, for example, when the amount of displacement between the input shaft 28 and the output shaft 30 due to a signal from the steering sensor 24 exceeds a set value when the steering wheel 8 is operated. The driving force of the electric motor 22 is transmitted to the output shaft 30 via a clutch mechanism (not shown), and various factors such as the engine speed and the vehicle speed are taken into consideration to assist the operating force of the steering wheel 8. It controls the driving force.

Next, the operation of this embodiment will be described.

When the steering wheel 8 is operated leftward and rightward, the elastic body 32 is twisted in the circumferential direction. The twist of the elastic body 32 causes the ball 74 to move along the sensing groove 78. The slider 64 moves in the axial direction of the input shaft 28 in conjunction with the operation of the ball 74.

As the slider 64 moves, the magnet 84
When M moves, the magnetic field strength around the first and second Hall elements 86-1 and 86-2 changes and the voltage output from the sensor body 60 changes, as shown in FIG.

That is, the first hall element 86-1 and the second hall element 86-2 have the inverted characteristics as shown in FIG.

FIG. 3 shows the contents shown in FIG. 4 by paying attention only to the input torque and the sensor output value. The characteristics shown in FIG. 3 are equivalent to the characteristics when the conventional link mechanism is used.

As a result, the slider 64 and the sensor body 60
By providing the non-contact type mediating means 62 between them, a function equivalent to that of the conventional link mechanism is obtained, the number of parts is reduced and the configuration is simplified, and it is not necessary to set the neutral point during the adjustment. In addition, the reliability can be improved by reducing the secular change, wear and failure.

Further, the non-contact type mediating means 62 has a magnet 84 provided on the slider 64 and two first and second elements 86 provided on the sensor body 60 so as to face the magnet 84.
-1, 86-2. As a result, the mounting is easy, and even if one Hall element fails, the amount of displacement can be detected by the other Hall element, so that fail-safe measures can be taken.

In the above-described embodiment, the sensor body 60 is provided with the two hall elements 86.
It is needless to say that even if one Hall element 86 is provided in the above, a sufficient sensor function can be exhibited.

[0043]

As is apparent from the above detailed description, according to the present invention, a non-contact type mediating means is provided between the slider and the steering sensor which are interlocked with the operation of the ball movably provided in the sensing groove of the input shaft. By providing the steering sensor, the amount of displacement due to relative rotation between the input shaft and the output shaft is detected without directly contacting the slider, reducing the number of parts and simplifying the configuration. Therefore, it is possible to improve the reliability by facilitating adjustment, reducing secular change, wear and failure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an electric power steering device.

FIG. 2 is a cross-sectional view taken along the line 〓-〓 of FIG.

FIG. 3 is a characteristic diagram of input torque-sensor value.

FIG. 4 is a characteristic diagram of a steering sensor when two Hall elements are used.

FIG. 5 is a schematic perspective view of a vehicle including an electric power steering device.

FIG. 6 is a sectional view of a conventional electric power steering device.

7 is a cross-sectional view taken along the line 〓-〓 of FIG.

[Explanation of symbols]

 2 vehicle 8 steering wheel 10 steering column 12 steering gear 14 steering shaft 20 electric power steering device 22 electric motor 24 steering sensor 26 control means 28 input shaft 30 output shaft 32 elastic body 60 sensor body 62 non-contact mediating means 64 slider 66 circumferential groove 74 Ball 78 Sensing groove 84 Magnet 86 Hall element

Claims (1)

[Claims] 1. An input shaft connected to a steering wheel of a vehicle and an output shaft connected to a steering gear are connected by an elastic body and provided so as to be relatively rotatable, and a ball is moved to a sensing groove formed in the input shaft. A slider, which is movably provided and is movable in the axial direction of the input shaft in association with the movement of the ball, is provided on the input shaft, and the movement of the slider causes a displacement amount due to relative rotation between the input shaft and the output shaft. A steering torque detecting device provided with a steering sensor for detecting, wherein a non-contact type mediating means is provided between the slider and the steering sensor.