JPH11255084A - Brake pedal actuating force detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect brake-pedal actuating force precisely with a simple structure that can be easily incorporated in a brake mechanism. SOLUTION: A clevis 7 that connects an arm 3 on a brake pedal 1 and an operating rod 5 on a booster to each other is provided with strain sensors 20 and 21 for outputting electrical signals according to the strain of the clevis 7 caused by the force transmitted from the brake pedal 1 to the operating rod 5. The clevis 7 is made out of an L-shaped member having a front plate 7a and a side plate 7b. The front plate 7a is mounted with the operating rod 5, while the side plate 7b is mounted on the inner surface of its tip with a cantilever pin 8, into which the brake pedal arm 3 is fitted, such that the side plate 7b remarkably presents a bending strain at its base portion where the strain sensors 20 and 21 are stuck on both upper and lower surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a brake pedal force detecting device.

[0002]

2. Description of the Related Art Conventional devices of this type include (a) a device in which a pedal force converter is mounted on a brake pedal, and (b)
Calculates the brake pedal depression force based on signals from a stroke sensor and master cylinder pressure sensor.
As described in Japanese Patent Application Laid-Open No. 0-68857, a device in which a load detector is incorporated in a booster is known.

[0003]

However, the above (a),
In (b), the accuracy is not high because the mounting error tends to appear in the output value. In particular, in the case of (b), there is a problem that the one utilizing the signal of the master cylinder pressure sensor is affected by disturbance such as hysteresis of the vacuum booster. (C) has a problem that the structure is complicated. Furthermore, all of the above-mentioned devices have been difficult to mount on a brake mechanism.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to provide a brake pedal force detection device which has a simple structure, is easily incorporated into a brake mechanism, and can detect the pedal force with high accuracy. I do.

[0005]

According to a first aspect of the present invention, a clevis for connecting an arm of a brake pedal to an operating rod of a booster is provided with an electric device in accordance with a distortion of the clevis due to a force transmitted from the brake pedal to the operating rod. The above problem has been solved by attaching a distortion sensor that outputs a signal.

When the driver depresses the brake pedal, the pedaling force is transmitted from the brake pedal to the operating rod of the booster via the clevis, and the clevis generates a distortion corresponding to the transmitted force. In particular, the clevis is a member located at the connection point between the brake pedal and the operating rod, so it is not affected by disturbance,
A distortion that accurately reflects the pedaling force is generated. Therefore, the distortion sensor outputs an electric signal corresponding to the driver's pedaling force with high accuracy.

[0007] In this case, since only the strain sensor is provided on the clevis, the structure is extremely simple, and the incorporation into the brake mechanism is easy. Therefore, the instability of the accuracy due to the mounting error hardly occurs. Also, the part where the driver directly applies the pedaling force (for example, the pedal tread plate)
Since the strain sensor is not provided in the vehicle, the pedaling force can be detected without causing the driver to feel uncomfortable.

According to a second aspect of the present invention, in the first aspect, the clevis is formed with a portion where the bending on the front and back surfaces is noticeably distorted when a bending force is applied, and the strain sensor is attached to the front and back surfaces of this portion. As a result, the above problem has been solved.

Since the strain caused by bending of a specific portion on the clevis is detected by a strain sensor attached to the front and back surfaces of the clevis, a very small strain can be reduced by forming a bridge circuit using the strain sensor as a resistor. Can be detected with high accuracy, and the detection accuracy of the pedaling force can be increased.

According to a third aspect of the present invention, in the second aspect, the clevis is formed of an L-shaped member having a front plate and a side plate, and the operating rod is provided on an outer surface of the front plate in a direction orthogonal to the front plate. Is fixed, a cantilever pin is attached to the inner surface of the tip of the side plate in a direction perpendicular to the operating rod, and the arm of the brake pedal is fitted to the cantilever pin so that the arm can be turned to the clevis. The above problem has been solved by connecting the base plate of the side plate to a portion where the distortion is remarkably exhibited, and attaching the strain sensor to the front and back surfaces of the base of the side plate.

In this device, when the driver depresses the brake pedal, the depressing force is transmitted to the side plate of the clevis made of an L-shaped member via the cantilever pin, and transmitted from the side plate to the operating rod via the front plate. . At this time, since the side plate is cantilevered with the base serving as a connection portion with the front plate as a fulcrum, the distance between the side plate and the arm on the cantilever pin from the cantilevered base to the side plate The bending moment according to the above acts, and a noticeable distortion due to bending is generated on the front and back surfaces of the base of the side plate. The distortion in this case is enlarged in proportion to the distance from the base of the side plate to the cantilever pin, and is converted into an electric signal and output by a distortion sensor attached to the front and back surfaces of this portion.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1, 2 and 3 are views showing an embodiment of the present invention. FIG. 1 shows the relationship among a clevis 7, a cantilever pin 8, and strain sensors 20 and 21, and FIGS. Reference numeral 3 denotes a relationship between the clevis 7, the brake pedal 1, and the operating rod 5 of the booster.

As shown in FIG. 2, the brake pedal 1
The tread plate 2 includes an arm 3 having an upper end rotatably supported by a pin 4 and a lower end to which the tread plate 2 is fixed. The arm 3 is connected to an operating rod 5 of a booster via a clevis 7. The clevis 7 is rotatably connected to a position slightly below the pin support point of the arm 3. When the brake pedal 2 is depressed, the force is transmitted to the operating rod 5 via the clevis 7. Has become.

As shown in FIGS. 1 and 3, the clevis 7
It is composed of a left-right asymmetric L-shaped member having a front plate 7a and a side plate 7b. The front plate 7a is provided with a screw hole 11, and the tip of the operating rod 5 of the booster located on the outer surface side of the front plate 7a is connected to the screw hole 11. The operating rod 5 is in a direction orthogonal to the front plate 7a.

A cantilever pin is attached to the inner surface of the distal end of the side plate 7b in a direction perpendicular to the operating rod 5. The cantilever pin 8 has its base end screwed into the screw hole 12 of the side plate 7b and is fixed to the side plate 7b by a nut 13. When the through hole 3a of the arm 3 of the brake pedal 1 is fitted to the cantilever pin 8, the brake pedal 1 and the clevis 7 are rotatably connected. Reference numeral 14 in FIG. 1 denotes a retaining pin.

As shown in FIG. 3, the clevis 7 in this case is
Is a left-right asymmetric L-shape, and a pin to which the brake pedal 1 is fitted is a cantilever pin 8. Therefore, FIG.
In contrast to the case where the force of the brake pedal 1 is received by the normal U-shaped clevis 37 and the both end support pins 38 as shown in (1), the bending moment about the base connected to the front plate 7a is provided on the side plate 7b of the clevis 7. M (see FIG. 3) acts, and the distortion near the base of the side plate 7b becomes the largest. Therefore, the strain sensors 20 and 21 whose resistance values change due to the strain are attached to the front and back surfaces (the outer surface and the inner surface) of the portion where the strain due to bending is remarkable. In this case, the front and back strain sensors 20, 21 are arranged in two orthogonal directions.

FIG. 5 shows an example of a bridge circuit incorporating the strain sensors 20 and 21 as resistors. The two strain sensors 20 on the side where the strain in the tensile direction is generated by the bending moment M (the outer surface side of the side plate 7b) are R1 and R3.
And two strain sensors 21 on the side where the bending moment generates a strain in the compression direction (the inner surface side of the side plate 7b).
A bridge is made as 2 and R4, and a voltage Vin is applied to the input terminal of the bridge. Then, between the output terminals,
Output voltage Vo according to resistance change of strain sensors 20 and 21
ut occurs.

Next, the operation will be described with reference to FIG.

When the pedaling force F from the brake pedal 1 is applied, the pedaling force F is transmitted to the side plate 7b of the clevis 7 via the arm 3 and the cantilever pin 8, and from the side plate 7b to the front plate 7
Via a, it is transmitted to the operating rod 5 of the booster. At this time, since the side plate 7b is cantilevered with the base serving as a connection portion with the front plate 7a as a fulcrum, the connection C
Moment M (= F1 × L:
In F1, a vertical component force of the pedaling force F with respect to the distance L is generated, and remarkable distortion due to bending is generated on the front and back surfaces of the base of the side plate 7b.

The distortion sensors 20 and 21 on the front and back sides convert this distortion into an electric signal and output it (output voltage Vout of the bridge circuit). Since the distortion in this case is proportional to the distance L and the pedaling force F, the pedaling force F can be measured by the outputs of the distortion sensors 20 and 21 (since the distance L is invariable). In addition, the use of the cantilever type clevis 7 allows the distortion to be detected after being greatly expanded, so that it is possible to accurately detect a subtle to strong pedaling force of the brake pedal 1.

The detection output of the pedaling force F can be used, for example, as one input element of the brake assist or as one element for vehicle development.

As shown in FIG. 4, even when the strain sensors 20 and 21 are attached to the U-shaped clevis 37,
Although the sensitivity to the treading force F is not good as in the above embodiment, the treading force can be detected.

[0024]

As described above, according to the first aspect of the present invention, the strain sensor is attached to the clevis located at the connection point between the brake pedal and the operating rod, and the pedaling force is detected based on the output of the strain sensor. Therefore, the pedaling force can be accurately detected without being affected by disturbance. In addition, since only the strain sensor is provided on the clevis, the configuration is simple, it is easy to assemble it into the brake mechanism, and instability in accuracy due to mounting errors hardly occurs.

According to the second and third aspects of the present invention, since a portion where distortion due to bending is remarkably formed on the clevis and the strain sensor is attached to the front and back surfaces, the strain sensor is used as a resistor. A bridge circuit can be configured, and the pedaling force can be detected with extremely high accuracy.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a clevis constituting a tread force detecting device according to an embodiment of the present invention.

FIG. 2 is an external perspective view of the pedaling force detection device according to the embodiment;

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a diagram showing a comparative example of the embodiment.

FIG. 5 is a diagram showing an example of a detection circuit used in the device according to the embodiment of the present invention.

[Description of Signs] 1 ... Brake pedal 3 ... Arm 5 ... Operating rod 7 ... Clevis 7a ... Front plate 7b ... Side plate 8 ... Cantilever pin 20,21 ... Strain sensor 37 ... Clevis 38 ... Double support pin

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Katsushige Uematsu 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Hiroaki Oka 1 Toyota Town, Toyota City, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (3)

[Claims] A clevis for connecting an arm of a brake pedal and an operating rod of a booster is provided with a strain sensor for outputting an electric signal corresponding to a clevis strain caused by a force transmitted from the brake pedal to the operating rod. Characteristic brake pedal force detection device. 2. The clevis according to claim 1, wherein the clevis is formed with a portion where the distortion of the front and back surfaces is remarkable when a bending force is applied, and the strain sensor is attached to the front and back surfaces of this portion. Brake pedal force detection device. 3. The clevis according to claim 2, wherein the clevis is formed of an L-shaped member having a front plate and a side plate, and the operating rod is fixed to an outer surface of the front plate in a direction orthogonal to the front plate. A cantilever pin is attached to the inner surface of the tip of the side plate in a direction perpendicular to the operating rod, and the arm of the brake pedal is rotatably connected to the clevis by fitting the arm of the brake pedal to the cantilever pin. The base of the side plate is formed as a portion where the distortion is conspicuous, and the strain sensor is attached to the front and back surfaces of the base of the side plate.