JPH01184466A - On-vehicle acceleration sensor - Google Patents

Abstract

PURPOSE:To obtain the detector having high reliability by inserting and placing a sphere through an elastic body in an optical path of two photoelectric converting elements provided in parallel and releasing the cut-off of the optical path of one photoelectric converting element by a movement of the sphere when acceleration is applied. CONSTITUTION:When acceleration is applied to an acceleration sensor 1, a sphere 6 moves by pressing an elastic body 7 in its accelerating direction. Accordingly, when a moving distance of the sphere 6 becomes above beta and its acceleration becomes above alpha, cut-off of an optical path of a light emission diode 4 is released and a light beam from the light emission diode 4 reaches a phototransistor 5, and a photoelectric converting element conducts thereby and generates an output. On the contrary, when deceleration exceeding a prescribed value is applied, the other photoelectric converting element consisting of a light emission diode 2 and a phototransistor 3 conducts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an on-vehicle acceleration sensor for detecting acceleration or deceleration of an automobile.

[Conventional technology]

In recent years, various electronic control devices have been installed in automobiles to control various functions. The anti-lock braking system controls the area where the frictional force between the road surface and the tires is maximum, ensuring the directional stability and steering performance of the vehicle.On the other hand, the anti-lock braking system controls the area where the frictional force between the road surface and the tires is maximum, ensuring the directional stability and steering performance of the vehicle. When the engine output becomes excessive and the wheel slip rate increases, the traction control system adjusts the opening of the engine throttle or applies brakes to prevent wheel slip and provide optimal acceleration control. Electronic control equipment plays an important role.

In the anti-lock braking system or traction control system, etc., wheel speed information and vehicle body acceleration information are taken in from wheel speed sensors and acceleration sensors, respectively, in order to optimize the control TJ.

As the above-mentioned acceleration sensor, one having a reed switch type configuration as shown in FIG. 4 is conventionally used. This sensor has a permanent magnet built into a pendulum supported by a horizontal rotating shaft, and a reed switch fixed vertically below the pendulum.

When used to detect the deceleration of the vehicle during braking, when the pendulum swings during deceleration and leaves the reed switch, the switch turns OFF. When the pendulum returns to its original position, the two reed pieces of the reed switch come into contact and are energized. In this way, the fact that deceleration increases on a road surface with a high friction coefficient is used to determine the road surface friction coefficient.

[Problem to be solved by the invention]

However, with conventional acceleration sensors, even if a malfunction occurs, such as a pendulum becoming stuck, it is difficult to detect it. It is used with some doubt about the information, assuming that it is of low gender.

However, for example, in the anti-lock braking system mentioned above, even the slightest problem in its control operation can develop into something that directly threatens human life. ! I
This cannot necessarily be said to be satisfactory in terms of the fail-safe design concept required for devices and the like.

This invention was made in view of the current state of the technology of vehicle-mounted acceleration sensors as described above, and its purpose is to use a photoelectric conversion element to act in both the acceleration direction and deceleration direction, and to have a simple configuration. The purpose of the present invention is to provide a highly reliable in-vehicle acceleration sensor.

[Means to solve the problem]

Therefore, as a means for solving the above problems, in the present invention, photoelectric conversion elements 2&Il consisting of a light emitting part and a light receiving part are arranged in parallel, and a sphere is inserted in the middle of the optical path so as to block the optical path of both elements. A configuration was adopted in which this sphere is surrounded by an elastic body, and when acceleration or deceleration is applied, the sphere moves in that direction, causing one of the photoelectric conversion elements to conduct.

[Effect]

For example, when used in an anti-lock braking system, the signal of the acceleration sensor according to the present invention configured as described above is transmitted on a road surface with a large coefficient of friction when the deceleration exceeds a certain value, and on a road surface with a low coefficient of friction when the deceleration is below a certain value. This is used to perform control appropriate to each road surface.

When a running car is braked, deceleration is applied to the acceleration sensor. This deceleration force causes the elastic body to stop moving, but the inertia force applied to the sphere causes the sphere to move forward. Therefore, the sphere presses the elastic body and moves relative to the elastic body. When this amount of movement exceeds a certain predetermined distance, the optical path of the photoelectric conversion element is unblocked, one photoelectric conversion element becomes conductive, and generates an output signal. This output signal is input to the electronic control device and subjected to arithmetic processing, thereby providing a command signal to the drive section.

When determining the acceleration when the car starts, the same effect is applied in the opposite direction to the above.

〔,Example〕

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

As shown in FIG. 1, the in-vehicle acceleration sensor 1 of this embodiment uses light emitting diodes as a light emitting part and a light receiving part, respectively.
Two sets of photoelectric conversion elements each consisting of -2.4 and phototransistor 3.5 are provided in parallel. A sphere 6 is inserted in the middle of the optical path of both photoelectric conversion elements so as to block the two optical paths. The sphere 6 is surrounded by an elastic body 7, and this elastic body 7 is supported by a frame 8. There is.

The sphere 6 uses a steel ball such as a pachinko ball or something equivalent. The elastic body 7 causes the sphere 6 to block the optical path of the photoelectric conversion element when an acceleration (or deceleration) of a predetermined value or more is applied. The material (such as rubber) is selected so as to have enough elasticity to release the photoelectric conversion element and move the distance necessary to conduct one of the two photoelectric conversion elements.This elastic body 7 is divided into two parts. Alternatively, only the portion holding the sphere may be cut into a cylindrical or prismatic shape.

The frame 8 may have any shape as long as it has an aperture necessary for irradiating the sphere with the above two optical paths.

When acceleration (or deceleration) is applied to the acceleration sensor 1 configured as described above, the sphere 6 presses the elastic body 7 in the acceleration direction and moves (see FIG. 2). Therefore, when the moving distance of the sphere 6 exceeds β and its acceleration exceeds the predetermined value α, the light path of the light emitting diode 4 is unblocked and the light from the light emitting diode 4 reaches the phototransistor 5, which causes the photoelectric conversion element to be activated. On the other hand, when a deceleration of a predetermined value or more is applied, another set of photoelectric conversion elements consisting of the light emitting diode 2 and the phototransistor 3 becomes conductive in exactly the same way.

The output signal of the acceleration sensor 1 is sent, for example, to a control box 10 of an anti-lock braking system as shown in FIG. The output signal sent from either of the two phototransistors 3.5 is sent to the microcomputer 1 after adjusting the voltage etc. at the interface 11.
2.

In the anti-rotation braking system, in addition to the signal from the acceleration sensor, a Washals signal representing the wheel speed is sent to the micro combinator 12 from a wheel speed sensor attached to the axle of the wheel.

The microcomputer 12 calculates the acceleration signal and the wheel speed pulse signal using its internal program to obtain the acceleration value, wheel speed, wheel slip rate, etc. (stored in the memory 13), and based on these calculation results, calculates the acceleration value, wheel speed, wheel slip rate, etc. A command signal is sent to the actuator drive circuit 14.15. The actuator is not shown in the figure, but in a brake control device using anti-lock control, it is incorporated in a hydraulic unit that controls the brake piping system to reduce, maintain, and increase the braking pressure from the brake mask cylinder. There are solenoid valves and the like, and these actuators are opened and closed by the above-mentioned command signals.

In the above calculation process, the signal from the acceleration sensor of this embodiment is used to control the opening and closing of the actuator to optimally control the opening and closing of the actuator in accordance with the road surface during anti-lock control.

〔effect〕

As explained in detail above, the acceleration sensor according to the present invention has a sphere inserted in the optical path of two sets of photoelectric conversion elements arranged in parallel via an elastic body, and when acceleration or deceleration is applied, the sphere Since the structure is configured so that the optical path of one of the photoelectric conversion elements is unblocked by movement and the output signal is taken out, it acts in either direction of acceleration or deceleration, and there is no rotating part unlike the conventional one. Failures are less likely to occur,
Therefore, it is more reliable than conventional methods.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of an acceleration switch according to the present invention, FIG. 2 is an explanatory diagram of operation, and FIG. 3 is a schematic block diagram of an electronic control device that processes signals of this acceleration switch.
FIG. 4 is a schematic diagram of a conventional example. 1... Vehicle-mounted acceleration sensor, 2.4... Light emitting diode, 3.5... Phototransistor, 6......
A sphere?・・・・・・Elastic body, 8・・・・・・
·flame. Patent applicant: Sumitomo Electric Industries, Ltd. Agent: Kama 1) Text 2 Figure 1 Figure 2 Figure 2 3-6 Convex-5 Figure 3 Construction Figure 4

Claims (1)

[Claims] 1) Two sets of photoelectric conversion elements consisting of a light emitting part and a light receiving part are provided in parallel, a sphere is inserted in the middle of the optical path so as to block the optical path of both elements, and this sphere is made of an elastic body. An on-vehicle acceleration sensor is constructed such that when acceleration or deceleration is applied, the sphere moves along the acceleration or deceleration direction, and one of the photoelectric conversion elements becomes conductive. (2) The vehicle-mounted acceleration sensor according to claim 1, wherein the light emitting section and the light receiving section are each formed of a light emitting diode and a phototransistor. (3) The elastic body is
When an acceleration of a predetermined value or more is applied, the sphere unblocks the optical path of the photoelectric conversion element and has such elasticity that it can move the distance necessary to conduct any one of the photoelectric conversion elements. The vehicle-mounted acceleration sensor according to claim 1 or 2.