JPH11139270A - Pedal depressing force detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pedal depressing force detection device which can be miniaturized and can reduce costs, can resist turbulence, and can stably detect with high accuracy the depressing force applied to a pedal. SOLUTION: A sensor unit 12 receiving the depressing force applied to a pedal includes a super-magnetostrictive material 121 producing a magnetic field according to compressive load, a coil 122 placed around the super- magnetostrictive material 121 and outputting signals proportional to changes in magnetic field to a control unit 8, and a push rod 123 by which the depressing force applied to the pedal 7 is transmitted to the super-magnetostrictive material 121 as a compressive force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pedal depression force detecting device for detecting a pedal depression force and outputting a signal corresponding to the pedal depression force.

[0002]

2. Description of the Related Art In recent years, brake systems for vehicles have been actively equipped with an intelligent brake function such as an anti-lock brake system and a traction control system. Brake devices are being electrified.

In order to operate the brake device according to the driver's request, a pedal depression force detecting device for accurately detecting a driver's depression of a brake pedal, and a pedal depression force detection device are disclosed. The performance of the control unit, which controls the operation of the brake device based on the signal from the vehicle, is an important point that determines the braking performance.

For example, in the related art, as shown in FIG. 5, as a pedal depression force detecting device, a depression force sensor 2 for detecting the depression force of the brake pedal 1 by a driver is provided in a depression portion 1a of a brake pedal 1 of a vehicle. Things are being developed. The brake pedal 1 itself normally provides a predetermined operation reaction force (brake feeling) when the driver steps down, and furthermore, when the driver releases his / her foot from the brake pedal 1, the brake pedal 1 It is elastically supported by the pedal urging spring 3 so as to return to the initial position. The above-described treading force sensor 2 outputs an electric signal according to the treading force of the driver, and for example, an existing load cell is used.

[0005]

However, in the conventional pedal depression force detecting device using an existing load cell, there is a problem that the pedal force sensor 2 itself has a relatively large size, which leads to an increase in the size of the pedal device. . Also, the sensor
There is also a problem that it is weak against external electromagnetic noise and vibration.

The present invention has been made in view of the above circumstances, and can not only reduce the size of the pedal device, but also is resistant to disturbances such as electromagnetic noise and can stably apply the pedaling force applied to the pedal with high precision. It is an object of the present invention to provide a pedal depression force detection device which can be detected at the same time and which is most suitable for electricization of a brake device of a vehicle.

[0007]

According to the present invention, there is provided a pedal depressing force detecting device for detecting a pedal depressing force in order to operate a predetermined device in accordance with a pedal depressing force. A pedal depression force detection device that outputs a signal according to the depression force of the pedal to a control unit that controls the operation of the device, wherein the pedal, a sensor unit that receives the depression force applied to the pedal, and the sensor unit Resilient means for pressing the pedal in the direction of its rest position through the sensor unit, wherein the sensor unit is provided with a giant magnetostrictive material that generates a magnetic field in accordance with a compressive load, and is arranged around the giant magnetostrictive material to change the magnetic field. A coil that outputs a corresponding signal to the control unit, and a push rod that transmits a pedaling force applied to the pedal to the giant magnetostrictive material as a compressive force. It is characterized in that it has provided.

According to the above structure, the pedaling force applied to the pedal acts as a compressive load on the giant magnetostrictive material constituting the sensor unit via the push rod. The change in the pedaling force applied to the pedal results in a change in the compressive load applied to the giant magnetostrictive material, and changes the magnetic flux density (magnetic field strength) generated from the giant magnetostrictive material. When the magnetic flux density generated from the giant magnetostrictive material changes, the electric signal output from the coil fluctuates accordingly,
By monitoring the electric signal output from the coil, the control unit can detect a change in the pedal effort and can output a predetermined control signal corresponding to the pedal effort to a predetermined device. And, for example, when it is assumed that the sensor unit is used for detecting the depression force of the brake pedal of the vehicle, the giant magnetostrictive material constituting the sensor unit has not only a high response speed to a load change of 50 to 100 μs but also a high speed. It is quite small with a diameter of 1 mm and a length of about 20 mm, and can exhibit sufficient sensing performance.
Further, a sensor that generates a magnetic flux density that changes in accordance with a compression load can eliminate the need for power supply from a power supply at all.

The elastic means may be formed by a plurality of springs having different elastic forces. In this case, for example, by arranging a plurality of springs in multiple stages, it is possible to make the reaction force characteristics of the pedal correspond to the output characteristics of the device that operates according to the pedaling force of the pedal.

[0010] The control unit includes:
It is preferable to provide an integrating circuit for integrating a signal output from the coil due to a magnetic field change of the giant magnetostrictive material. When the signal output from the coil is integrated by the change in the magnetic field of the giant magnetostrictive material, the change in the pedaling force actually applied to the pedal can be accurately restored as a voltage change.

Further, it is preferable that a yoke for accommodating and holding the giant magnetostrictive material and the coil and covering them to form a closed magnetic circuit is provided, and the push rod is inserted through the yoke. In this way, the coil and the giant magnetostrictive material in the yoke are electromagnetically shielded from the outside,
The detection accuracy does not decrease due to disturbance, and the pedaling force applied to the pedal can be detected stably and with high accuracy.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a pedal depression force detecting device according to the present invention will be described below in detail with reference to the drawings. 1 is a side view of a main part of a vehicle equipped with a pedal depression force detection device according to the present invention, FIG. 2 is a configuration diagram of the pedal depression force detection device, and FIG. 3 is a longitudinal sectional view showing a configuration of a sensor unit of the pedal depression force detection device. FIG. 4 is a graph showing the correlation between the brake depression force and the output signal of the sensor unit. As shown in FIG. 1, the pedal depression force detection device 6 of this embodiment
The brake pedal 7 supports the brake pedal 7, detects the pedaling force F applied to the pedal 7, and sends a signal corresponding to the pedaling force applied to the pedal 7 to the control unit 8 (see FIG. 3). The control unit 8 controls the operation of the brake device according to the pedaling force applied to the pedal 7.

As shown in FIG. 2, the pedal depression force detecting device 6 includes a pedal 7, a support frame 10 fixed to a vehicle body to support the pedal 7 so that the pedal 7 can be stepped down, and A sensor unit 12 that is housed and held in the pedal and receives a pedaling force applied to the pedal 7, an elastic unit 14 that presses the pedal 7 toward the rest position via the sensor unit 12, and an elastic unit 14. The sensor unit 12 is urged in a direction opposite to the urging direction so that the end surface of the sensor unit 12 is
And gap maintaining means 16 for preventing collision with zero.

As shown in FIG. 3, the sensor unit 12 comprises a substantially rod-shaped giant magnetostrictive material 121 for generating a magnetic field in response to a compressive load applied from the outside,
1 and a coil 122 for outputting a signal corresponding to a change in the magnetic field to the control unit 8. One end of the coil 122 is in contact with the giant magnetostrictive material 121 and the other end is connected to the brake pedal 7. 7, a push rod 123 for transmitting the treading force applied to the giant magnetostrictive material 121 to the giant magnetostrictive material 121 as a compressive force, and accommodating and holding the giant magnetostrictive material 121, the coil 122, and one end of the push rod 123, and covering and covering them. 125 and the end wall member 12 on the pedal side of the yoke 125
6 and one end of the push rod 123 in a compressed state, and is constituted by a preload spring 127 for applying an auxiliary compressive load to the giant magnetostrictive material 121 through the push rod 123. .

The push rod 123 has one end surface abutting on the end of the giant magnetostrictive material 121 and the other end surface functioning as a spring receiving portion on which the preload spring 127 is seated. A shaft portion 123b protruding from the center of the shaft member and penetrating the end wall material 126.
The shaft portion 123b projecting outside from the end wall member 126 further projects outside the support frame 10, and the pedal 7 is connected to the tip of the shaft portion 123b.
A portion of the shaft portion 123b protruding from the support frame 10 includes:
A bellows-shaped boot 18 is covered.

The preload spring 127 is formed by stacking two disc springs in opposite directions, and by applying a constant compressive load to the giant magnetostrictive material 121 in advance, the response of the giant magnetostrictive Is good.

The elastic means 14 is provided in a housing 101 of the support frame 10 in which the pedal depression force detecting device 6 is housed.
Are mounted in a compressed state between the inner bottom portion 102 and the sensor unit 12, and are configured by arranging two compression springs 141 and 142 having different elastic forces in series. The gap holding means 16 is provided on the shaft 12 of the push rod 123.
When the pedal 7 returns to the rest position, a compression spring is disposed between the upper end wall 103 of the housing portion 101 through which the insertion portion 3b is inserted and the end wall member 126 of the sensor unit 12. The sensor unit 12 is urged in a direction opposite to the elastic means 14 so as not to interfere with the wall 103.

The control unit 8 for controlling the operation of the brake device based on the output of the coil 122
Has a built-in integrating circuit (not shown) that integrates a signal output from the coil 122 due to a change in the magnetic field of the giant magnetostrictive material 121. The integrating circuit adds a signal to the pedal 7 as shown in FIG. The operation of the brake device is controlled by integrating the change in the applied pedal force into a voltage.

According to the pedal force detecting device 6 described above, the pedal force applied to the pedal 7 is transmitted through the push rod 123 to the giant magnetostrictive material 121 constituting the sensor unit 12.
Acts as a compressive load. Then, the change in the pedaling force applied to the pedal 7 changes the compressive load applied to the giant magnetostrictive material 121, and changes the magnetic flux density (magnetic field intensity) generated from the giant magnetostrictive material 121. When the magnetic flux density generated from the giant magnetostrictive material 121 changes, the electric signal output from the coil 122 fluctuates in accordance with the change. Therefore, by monitoring the electric signal output from the coil 122, the control unit 8 Can detect a change in the pedaling force of the pedal 7, and can output a control signal obtained by integration according to the pedaling force of the pedal 7 to a predetermined device.

The giant magnetostrictive material 121 forming the sensor unit 12 has a response speed of 5 to load variation.
Since the speed is as fast as 0 to 100 μs, high-speed pedal force detection is possible. The giant magnetostrictive material 121 is, for example,
When it is assumed to be used for detecting the depression force of the brake pedal 7 of the vehicle or the like, it is a very small one having a diameter of 1 mm and a length of about 20 mm, and exhibits sufficient sensing performance.
Further, the operation as a sensor for changing the magnetic flux density generated according to the change in the compression load does not require any driving power supply. Therefore, downsizing of the pedal 7 device can be achieved by downsizing the sensor unit 12.

Further, since the elastic means 14 has two springs having different elastic forces arranged in series, the reaction force characteristic of the pedal 7 is made to correspond to the output characteristic of the device which operates according to the pedaling force of the pedal 7. For example, it is possible to provide an excellent operation feeling.

In the case where the change in the pedaling force (N) applied to the pedal 7 during braking is in the form shown in the graph of FIG.
The change in the magnetic flux density (T) output from the giant magnetostrictive material 121 in the sensor unit 12 becomes the form shown in the graph of FIG. 4 (b) by only slightly releasing the brake. Is difficult to understand. However, in the case of the present embodiment, the control unit 8 is provided with an integrating circuit that integrates a signal output from the coil 122 due to a change in the magnetic field of the giant magnetostrictive material 121. The change in the pedaling force can be restored with high accuracy as the voltage change shown in FIG. 4C, and the detection accuracy of the pedaling force applied to the pedal 7 can be improved.

Further, a yoke 125 for accommodating and holding the giant magnetostrictive material 121 and the coil 122 and covering them to form a closed magnetic circuit is provided, and the push rod 123 is inserted through the yoke 125. The coil 122 and the giant magnetostrictive material 121 in the 125 are completely shut off from the outside, so that the detection accuracy does not decrease due to the influence of external electromagnetic noise, and the pedaling force applied to the pedal 7 is stably detected with high accuracy. can do. Therefore,
It is resistant to disturbance, can detect the pedaling force of the brake pedal 7 as a voltage signal stably and with high accuracy, and can realize a brake pedal device that is most suitable for electrification of the brake device and the like.

The pedal depression force detecting device of the present invention can be widely used for brake pedals of automobiles, railway vehicles, industrial machines and the like. Further, the present invention can be used not only for a brake pedal but also for an accelerator pedal and the like.

[0025]

According to the pedal depression force detecting device of the present invention,
The pedaling force applied to the pedal acts as a compressive load on the giant magnetostrictive material constituting the sensor unit via the push rod. And the change in pedaling force applied to the pedal is
The change in the compressive load applied to the giant magnetostrictive material changes the magnetic flux density (magnetic field intensity) generated from the giant magnetostrictive material. When the magnetic flux density generated from the giant magnetostrictive material changes, the electric signal output from the coil fluctuates accordingly. By monitoring the electric signal output from the coil, the control unit can determine the pedaling force of the pedal. The change can be detected, and a predetermined control signal corresponding to the pedal effort can be output to a predetermined device. Since the giant magnetostrictive material constituting the sensor unit has a high response speed to a load change of 50 to 100 μs,
High-speed treading force detection becomes possible. The supermagnetostrictive material has a diameter of 1 mm and a length of 20 m, for example, assuming that the material is used for detecting the depression force of a brake pedal of a vehicle.
It is quite small, about m, and exhibits sufficient sensing performance. Therefore, the size of the pedal device can be reduced by reducing the size of the sensor unit, so that the cost can be reduced by simplifying the mounting structure.

Further, when the elastic means is formed by a plurality of springs having different elastic forces, for example, by arranging the plurality of springs in multiple stages, the reaction force characteristic of the pedal is operated according to the pedaling force of the pedal. Such as matching the output characteristics of the device,
An excellent operation feeling can be provided.

The control unit includes:
With a configuration provided with an integration circuit that integrates a signal output from the coil due to a change in the magnetic field of the giant magnetostrictive material, a change in the pedaling force actually applied to the pedal can be accurately restored as a voltage change. The detection accuracy of the pedaling force applied to the pedal can be improved.

Further, when a yoke for accommodating and holding the giant magnetostrictive material and the coil and covering them to form a closed magnetic circuit is provided and the push rod is inserted through the yoke, the coil and the ultra The magnetostrictive material is completely shielded from external electromagnetic noise, so that the detection accuracy does not decrease due to the influence of external electromagnetic noise, and the pedaling force applied to the pedal can be detected stably and with high accuracy. . Therefore, for example, if the brake pedal is used for detecting the depression force of the brake pedal of a vehicle, the brake pedal is strong against disturbance, and can detect the depression force of the brake pedal as a voltage signal stably and with high accuracy. The device can be realized.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of a vehicle equipped with a pedal depression force detecting device according to the present invention.

FIG. 2 is a configuration diagram of the pedal depression force detection device of FIG. 1;

FIG. 3 is a longitudinal sectional view showing a configuration of a sensor unit in FIG.

FIG. 4 shows the pedaling force in the pedaling force detection device of FIG.
6 is a graph showing a correlation between a change in a magnetic field and a voltage of a sensor unit output.

FIG. 5 is a schematic configuration diagram of a conventional pedal depression force detection device.

[Description of Signs] 6 Pedal depression force detection device 7 Pedal 8 Control unit 10 Support frame 12 Sensor unit 14 Elastic means 16 Gap holding means 18 Boot 121 Giant magnetostrictive material 122 Coil 123 Push rod 125 Yoke 127 Preload spring

Claims (4)

[Claims] 1. A signal corresponding to a pedaling force of a pedal is output to a control unit that detects the pedaling force of a pedal and controls the operation of the predetermined device in order to operate the predetermined device in accordance with the pedaling force of the pedal. A pedal depression force detecting device, comprising: a pedal; a sensor unit for receiving a depression force applied to the pedal; and elastic means for pressing the pedal toward the rest position via the sensor unit. Is a giant magnetostrictive material that generates a magnetic field in accordance with a compressive load, a coil disposed around the giant magnetostrictive material and outputs a signal corresponding to a magnetic field change to the control unit, and a pedaling force applied to the pedal. A push rod for transmitting a compressive force to the giant magnetostrictive material. 2. The pedal depression force detecting device according to claim 1, wherein said elastic means is formed by a plurality of springs having different elastic forces. 3. The control unit according to claim 1, wherein an integration circuit for integrating a signal output from the coil due to a magnetic field change of the giant magnetostrictive material is provided.
The pedal depression force detection device according to any one of the preceding claims. 4. A yoke for accommodating and holding said giant magnetostrictive material and said coil and covering them to form a closed magnetic circuit, wherein said push rod is inserted through said yoke. Pedal force detection device.