JPH0792010A - Load measuring device for installation on vehicle - Google Patents

Abstract

PURPOSE:To simplify the installation on a vehicle and to facilitate the correspondence with elastic characteristics of a chassis spring. CONSTITUTION:An ultrasonic wave is transmitted to a structure member of an axle housing AH journalling a vehicle wheel W from an ultrasonic transducer TRR and an ultrasonic transducer TRL, both of which are arranged under a deck 110 of a vehicle to be reflected by the structural member of the axle housing AH, and a distance between the structure member of the axle housing AH and the ultrasonic transducer TRR or the ultrasonic transducer TRL arranged under the deck 110, and consequently, a load is calculated on the basis of the distance between the structure member of the axle housing AH and the ultrasonic transducer TRR/the ultrasonic transducer TRL.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device mounted on an automobile for measuring a vehicle loading amount, and more particularly to a vehicle-mounted loading amount measuring device for measuring a vehicle loading amount by ultrasonic waves. is there.

[0002]

2. Description of the Related Art As a conventional vehicle-mounted load measuring device,
The elastic force of a chassis spring having a known elastic characteristic is used, and the variable amount is mechanically detected to determine the load capacity of the vehicle. An example of a known document of this type of vehicle-mounted load amount measuring device in a patent publication is Japanese Patent Publication No. 4-59572.

[0003]

However, in the on-vehicle load amount measuring device for measuring the load amount of the vehicle by detecting the mechanical displacement described above, the mechanism constituting the device is mechanically and firmly attached. However, it was not suitable for retrofitting.

Further, when the elastic characteristics of the chassis spring of the vehicle are made non-linear, for example, when the elastic coefficient is discontinuous during the displacement of the chassis spring, it is difficult to match the mechanical displacement characteristics. It was

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle-mounted load measuring device which can be easily mounted on a vehicle and which can easily match the elastic characteristics of a chassis spring.

[0006]

An on-vehicle load amount measuring apparatus of the present invention is arranged in a lower portion of a vehicle body of a vehicle, transmits an ultrasonic wave vertically below the vehicle body, and receives the reflected wave. It is provided with a wave transmitter / receiver and a component of an axle housing accommodating an axle shaft for transmitting a driving force to a wheel that reflects the ultrasonic waves from the ultrasonic wave transmitter / receiver.

[0007]

According to the present invention, the ultrasonic wave is transmitted from the ultrasonic wave transmitter / receiver arranged at the lower portion of the vehicle to the constituent member of the axle housing that pivotally supports the wheels, and is reflected by the constituent member of the axle housing. Measuring the distance between the ultrasonic transducer arranged at the lower part of the vehicle and calculating the load based on the distance between the constituent member of the axle housing and the ultrasonic transducer. You can

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle mounted load measuring device according to an embodiment of the present invention will be described below.

<Explanation of Basic Operation> FIG. 1 is an explanatory view of a basic operation of a vehicle-mounted load measuring device according to an embodiment of the present invention. FIG. 2 (b) is a rear view of a case where a truck is equipped with the device of the present embodiment, and FIG. 2 is an exploded explanatory view in which a vehicle is equipped with the vehicle-mounted load measuring device according to the embodiment of the present invention. .

In FIG. 1A, a vehicle 1 such as a truck
The ultrasonic wave transmitter / receiver TRR and the ultrasonic wave transmitter / receiver TRL are attached to the lower part of the cargo bed 110 inside the rear wheel of 00 and outside both chassis springs SP. That is, the ultrasonic wave transmitter / receiver TRR and the ultrasonic wave transmitter / receiver TRL are located on both sides of the gear carrier assembly GA.

In FIG. 1B, an ultrasonic wave transmitter / receiver TR
R and the ultrasonic transmitter / receiver TRL are the loading platform 110 of the vehicle 100.
Rear axle case that is attached to the lower part of the vehicle and that transmits vertically downward 200 [KHz] band ultrasonic vibration with a predetermined ultrasonic beam width and that accommodates the axle shaft AS (see FIG. 2) connected to the wheel W. RA, gear carrier assembly GA
The reflected wave is received from the constituent members of the axle housing AH including the above. This ultrasonic transducer TR
The R and the ultrasonic transmitter / receiver TRL are housed in a housing B and integrated with a printed circuit board and the like.

In this embodiment, the ultrasonic wave transmitter / receiver TRR and the ultrasonic wave transmitter / receiver TRL are arranged so that the load applied to the rear wheels on both sides of the gear carrier assembly GA can be measured. It is also possible to measure the approximate load of the bed 110 by mounting the ultrasonic transducers TR on the top of the gear carrier assembly GA. Further, the front wheels may be individually arranged.

That is, the total load applied to each wheel W is used as the total load applied to the vehicle 100, but depending on the vehicle type, the load applied to both the center W of the rear wheels or both wheels W of the rear wheels is applied to the vehicle body. It can be a rough load.

<Basic Principle of Embodiment> Ultrasonic Transducer TR
The housing B of R and the ultrasonic transmitter / receiver TRL is the bed 11
No. 0 attached to the bottom surface of the carrier 110 of this embodiment.
The ultrasonic wave transmitter / receiver TR R, the ultrasonic wave transmitter / receiver TRL, and the height of the ultrasonic wave reflected by the axle housing AH are the vehicle height H 0 [m] when the load capacity is zero, and the measured vehicle height when the load capacity is a certain value. It is assumed that H [m] is reached.

The measured vehicle height H [m] between the ultrasonic wave transmitter / receiver TR R and the ultrasonic wave transmitter / receiver TRL of the loading platform 110 and the axle housing AH is a sound velocity C = 345 [m / s] at 15 ° C.
If the arrival time Se [s] of the reflected wave is expressed as H = 345 · Se / 2, the external temperature at that time is expressed as t ° C., then H = C · Se / 2 (where C = 331. 5 + 0.607t) ... (1).

To convert this into a loading amount W, W = k (H−H0) (where k is the spring constant of the loading platform 110) (2), and equations (1) and (2) are obtained. Therefore, the loading amount W can be easily obtained.

If the spring constant k does not change linearly, the relationship between the measured vehicle height H and the spring constant k may be stored in a memory map, and the loading amount W may be read directly from the memory map. May be read, and the loading amount W may be calculated accordingly.

<Circuit Configuration of Embodiment> FIG. 3 shows a controller 120 in a vehicle-mounted load measuring device according to an embodiment of the present invention.
2 is a circuit configuration diagram of FIG.

In FIG. 3, a microcomputer 1 having an A / D converter inside is a known one having a RAM, a ROM and an arithmetic unit necessary for arithmetic control inside. Omit it.

The ultrasonic wave transmitter / receiver TR R and the ultrasonic wave transmitter / receiver TRL are for transmitting and receiving ultrasonic vibration in the 200 [KHz] band with a predetermined ultrasonic beam width.

Further, the transmission circuit 10 is an ultrasonic wave transceiver TR.
The ultrasonic wave is output from R and the ultrasonic wave transmitter / receiver TRL, and the transmission cycle determining circuit 11 is composed of a monostable circuit of the next stage depending on "1" or "0" of the output terminal P1 of the microcomputer 1. A circuit for outputting a timing signal such as a trigger signal to the transmission pulse width determination circuit 12, which is a circuit for shaping a repeated timing signal for outputting ultrasonic vibrations from the ultrasonic wave transmitter / receiver TRR and the ultrasonic wave transmitter / receiver TRL, In this embodiment, 0.1 [mse of the output terminal P1 is used.
It is used as a timing signal by "1" in c]. The transmission pulse width determining circuit 12 receives the trigger signal from the transmission cycle determining circuit 11 and outputs it repeatedly with a predetermined pulse width. The transmission frequency generation circuit 13 is an oscillation circuit that outputs an ultrasonic frequency in the 200 [KHz] band that outputs ultrasonic vibrations from the ultrasonic wave transmitter / receiver TR R and the ultrasonic wave transmitter / receiver TRL, or the clock of the microcomputer 1. It is an oscillator circuit that divides a pulse or multiplies and divides the output of a predetermined oscillator to output an ultrasonic frequency. The transmission wave booster circuit 14 calculates the logical product of the outputs of the transmission pulse width determination circuit 12 and the transmission frequency generation circuit 13, and further,
The ultrasonic wave transmitter / receiver TRR and the ultrasonic wave transmitter / receiver TRL
It is a circuit that boosts voltage to a predetermined amplitude so that efficient transmission and reception can be performed.

The transmission cycle determining circuit 11, the transmission pulse width determining circuit 12, the transmission frequency generating circuit 13, and the transmission wave boosting circuit 14 constitute the transmitting circuit 10 of this embodiment.

Therefore, when the microcomputer 1 intermittently sets the output P1 to "1", the transmission wave boosting circuit 14 synchronizes with it and the ultrasonic wave transmitter / receiver TR generates ultrasonic waves.

The receiving circuit 20 inputs the ultrasonic vibrations received by the ultrasonic wave transmitter / receiver TRR and the ultrasonic wave transmitter / receiver TRL, and the reception protection circuit 21 thereof is a transmission wave booster circuit while the transmission circuit 10 is operating. It is a transmission / reception switching circuit that blocks the output of 14 and inputs only the reflected wave and outputs it to the received wave filter circuit 22. The reception wave filter circuit 22 is a filter circuit that removes noise of the reception wave. The output of the reception wave filter circuit 22 is amplified by the reception wave amplification circuit 23 and envelope-detected by the reception wave detection circuit 24. It is input to the comparison circuit 25. The comparison circuit 25 compares with a predetermined threshold value, judges the arrival of the reflected wave from the regular axle housing AH by its amplitude, and detects the arrival of the reflected wave from the predetermined axle housing AH. At that time, it is input to the terminal D1 of the microcomputer 1.

Further, the outside air temperature is detected by the thermistor 26, and the microcomputer 1 is sent through the amplifier circuit 27.
It is input to the terminal A1 of the built-in A / D converter.

These reception protection circuit 21, reception wave filter circuit 22, reception wave amplification circuit 23, reception wave detection circuit 24,
The comparison circuit 25 constitutes the reception circuit 20 of this embodiment.

Therefore, by measuring the time from when the microcomputer 1 intermittently sets the output P1 to "1" to when the terminal D1 is set to "1" due to the arrival of the reflected wave, the ultrasonic transducer A distance that is twice the distance between TRR and the ultrasonic transducer TRL and the axle housing AH can be detected.

Further, an ignition switch is connected to the terminal D2 of the microcomputer 1 and a measuring switch is connected to the terminal D3 of the microcomputer 1.

The controller 120 of this embodiment includes a transmitter circuit 10 and a receiver circuit 20, an ultrasonic wave transmitter / receiver TRR and an ultrasonic wave transmitter / receiver TRL, a thermistor 26, an amplifier circuit 27,
It is composed of a microcomputer 1.

<Overall Basic Operation> The transmitting circuit 10 and the receiving circuit 20 of this embodiment operate as follows.

In the transmission circuit 10 of this embodiment, burst waves having a frequency of 200 [KHz] and a duration of about 1 [msec] are transmitted from the ultrasonic transmitter / receiver TR R and the ultrasonic transmitter / receiver TRL every 100 [msec]. It will be explained on the assumption that it is sent.

First, the terminal P1 of the microcomputer 1
A gate signal for more burst wave output is output. The transmission pulse width determination circuit 12 which inputs the gate signal,
In order to output a burst wave having a duration of about 1 [msec], which is transmitted every 100 [msec], a corresponding pulse width of about 1 [msec] is generated, and the transmission wave boosting circuit 14 transmits the pulse width to the transmission pulse width determining circuit 12. The logical product of the outputs of the transmission frequency generation circuit 13 is calculated, and a burst wave corresponding to a pulse width of 1 [msec] and having a predetermined amplitude is output to the ultrasonic transducer TR. During this time, the reception protection circuit 21 on the reception circuit 20 side
Is the output of the transmission wave booster circuit 14 is the reception wave filter circuit 2
Prevents intrusion into the second and subsequent circuits.

Further, in the receiving circuit 20, when the output from the transmitting circuit 10 side is cut off, the ultrasonic transducer TRR is transmitted.
And the ultrasonic transmitter / receiver TRL receives the reflected wave from the axle housing AH, the reception protection circuit 21 inputs the reflected wave, outputs it to the received wave filter circuit 22, and the received wave filter circuit 22 receives it. The wave noise is removed, the received wave amplification circuit 23 amplifies the noise, the received wave detection circuit 24 performs envelope detection, the output is input to the comparison circuit 25, and the comparison circuit 25 compares it with a predetermined threshold value. When the arrival of the reflected wave from the normal axle housing AH is detected and the arrival of the reflected wave from the predetermined axle housing AH is detected, it is input to the terminal D1 of the microcomputer 1.

<Program Control Operation> FIG. 4 is a microcomputer 1 of a vehicle-mounted load measuring device according to an embodiment of the present invention.
3 is a flow chart of a main program executed by.
Further, FIG. 5 is a flow chart of a "load weight calculation" routine executed by the microcomputer 1 of the vehicle-mounted load measurement device of the present embodiment, FIG. 6 is a flow chart of a "displacement amount calculation" routine, and FIG. It is a flowchart of a "load calculation" routine. FIG. 8 is a flow chart of the "display and alarm" routine.

When a power source (not shown) is turned on, the microcomputer 1 is operated by a power-on reset circuit.
Starts operation, clears various memories, counters, and timers or sets them to predetermined values in step S1, initializes each output port, etc., and determines whether the weighing switch is turned on in step S2. Check to turn on the ignition switch. When it is determined that the weighing switch is turned on or the ignition switch is turned on, the processing in step S4 and subsequent steps is started.

In step S4, the "loading weight calculation" routine is called, and in step S5, the "display and warning" routine is called. Then, in step S6, it is determined whether or not the time set as the predetermined metering time has elapsed since the metering switch was turned on or the engine has started, and the time set as the predetermined metering time has elapsed since the metering switch was turned on or the engine has started. Until then, the routine from step S4 to step S6 is repeatedly executed. When the time set as the predetermined measurement time elapses from the start of the engine starting by turning on the metering switch or turning on the ignition switch, it is determined in step S7 that the metering switch is turned on. That is, after the ignition switch is turned on and the time set as the predetermined measurement time is up from the start of the engine, the metering switch is turned on to perform the measurement.

When the "load weight calculation" routine (see FIG. 5) is called in step S4, the "displacement amount calculation" routine is called in step S41, the "axial load calculation" routine is called in step S42, and the step S43
The load weight is calculated by summing up the values calculated for the respective axial loads and totaling them.

When the "displacement amount calculation" routine (see FIG. 6) is called in step S41, a timing signal for outputting an ultrasonic wave of 1 [msec] is generated in step S411, and the current counter value is read in step S412. The
The ultrasonic waves are received in step S413, and then step S414
The counter value is read in, the increment value of the counter value is calculated in step S415, the ambient temperature is measured in step S416, and the displacement amount is calculated in step S417 using the equations (1) and (2). .

When the "axial load calculation" routine (see FIG. 7) is called in step S42, a comparison is made with the previous displacement amount in step S420.
When the previously calculated axial load is set as the axial load in step S421 and the displacement amount is larger than the previous displacement amount, step S42
In step 2, the spring constant k at that time is used to calculate the axial load, and when it is smaller than the previous displacement amount, step S42.
In 3, the axial constant is calculated using the spring constant k at that time.

When the "display and warning" routine (see FIG. 8) is called in step S5, it is determined in step S51 whether the loaded weight is within a specified value, and if it exceeds the specified value, overloading is performed in step S52. After the alarm is issued, and when the specified value is not exceeded, the step S53 is directly executed.
Display the loaded weight with.

As described above, the in-vehicle load measuring device of this embodiment is arranged below the loading platform 110 of the vehicle 100, transmits ultrasonic waves vertically below the loading platform 110, and receives the reflected waves. Ultrasonic wave transmitter / receiver TRR and ultrasonic wave transmitter / receiver TRL
And the ultrasonic transmitter / receiver TR R and the ultrasonic transmitter / receiver TR
It is provided with a component of a predetermined axle housing AH accommodating an axle shaft AS that transmits a driving force to a wheel W that reflects the ultrasonic wave from L.

Therefore, the ultrasonic wave is transmitted from the ultrasonic wave transmitter / receiver TRR and the ultrasonic wave transmitter / receiver TRL disposed under the cargo bed 110 of the vehicle 100 to the constituent members of the axle housing AH which pivotally supports the wheel W. Then, the ultrasonic wave transmitter / receiver TR R or the ultrasonic wave transmitter / receiver TR, which is reflected by the constituent members of the axle housing AH and is disposed below the cargo bed 110.
The distance between L and L is measured, and the components of the axle housing AH and the ultrasonic transducer TR R and the ultrasonic transducer TR are measured.
The load capacity can be calculated based on the distance from L.

In particular, in this embodiment, the load can be detected by the mechanical displacement between the ultrasonic wave transmitter / receiver TRR or the ultrasonic wave transmitter / receiver TRL and the constituent members of the axle housing AH. Even if it is attached later, it can be easily attached.

Further, the chassis spring SP of the vehicle 100
Of the steady state mechanical displacement even if the elastic characteristics of the are made non-linear, or even if the elastic coefficient is discontinuous during the displacement of the chassis spring SP without being restricted by the structure and shape of the suspension. Thus, the load can be easily calculated by using the memory map in which the load corresponding to the mechanical displacement is associated.

By the way, the ultrasonic wave transmitter / receiver which is arranged in the lower part of the vehicle 100 of the above-mentioned embodiment and which transmits the ultrasonic wave vertically downward and receives the reflected wave is provided in the lower part of the bed 110 of the vehicle 100. The ultrasonic wave is transmitted vertically below the loading platform 110,
The ultrasonic wave transmitter / receiver that receives the reflected wave and the ultrasonic wave transmitter / receiver TRL have been described as an example, but in the case of practicing the present invention, they may be arranged for each wheel W, or the rear wheels. It may be arranged at the center of each wheel or rear wheel. Of course, when an ultrasonic wave transmitter / receiver is provided for each wheel W of all the wheels W, the detection accuracy can be increased.

Further, the cargo bed 11 of the vehicle 100 of the above embodiment.
The ultrasonic wave transmitter / receiver TR R and the ultrasonic wave transmitter / receiver TRL arranged at the lower part of 0 output ultrasonic waves vertically downward of the vehicle body, but in the case of practicing the present invention, they are not necessarily vertically downward. The position is not limited, and may be almost vertically downward. Of course, the ultrasonic wave transmitted from the ultrasonic wave transmitter / receiver arranged tends to have high accuracy in the vertical downward direction parallel to the direction in which the vehicle body is displaced by the load, but even if the ultrasonic wave is inclined, the accuracy decreases. It is possible to calculate the load.

The constituent members of the axle housing AH for reflecting the ultrasonic wave in the above embodiment are premised on the axle housing AH, but in the case of embodying the present invention, they are displaced integrally with the axle housing AH. Any component may be used.

[0048]

As described above, in the on-vehicle load measuring device according to the present invention, the ultrasonic wave transmitter / receiver arranged in the lower portion of the body of the vehicle is superposed on the constituent members of the axle housing that pivotally supports the wheels. Sound waves are transmitted and reflected by the constituent members of the axle housing, the distance between the ultrasonic transducer and the ultrasonic transmitter / receiver arranged under the vehicle body of the vehicle is measured, and the constituent members of the axle housing and the ultrasonic transmitter / receiver are The load capacity can be calculated based on the distance between the two. That is, since the load can be detected by the mechanical displacement between the ultrasonic wave transmitter / receiver and the constituent members of the axle housing, the mounting can be easily performed even when the ultrasonic wave transmitter / receiver is retrofitted to the vehicle. Also, if the chassis spring elasticity of the vehicle is made non-linear,
Alternatively, even if the elastic coefficient is discontinuous during the displacement of the chassis spring without being restricted by the structure and shape of the suspension, the load corresponding to the mechanical displacement can be detected by detecting the mechanical displacement in the steady state. The load can be easily calculated by using the associated memory map.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a basic operation of a vehicle-mounted load amount measuring device according to an embodiment of the present invention.

FIG. 2 is an exploded view of a vehicle equipped with a vehicle-mounted load measuring device according to an embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a vehicle-mounted load measuring device according to an embodiment of the present invention.

FIG. 4 is a flowchart of a main program executed by the microcomputer of the vehicle-mounted load measuring device according to the embodiment of the present invention.

FIG. 5 is a flowchart of a “load weight calculation” routine executed by the microcomputer of the vehicle-mounted load amount measuring apparatus according to the embodiment of the present invention.

FIG. 6 is a flowchart of a “displacement amount calculation” routine executed by the microcomputer of the vehicle-mounted load measuring device according to the embodiment of the present invention.

FIG. 7 is a flowchart of a “axial load calculation” routine executed by the microcomputer of the vehicle-mounted load measuring device according to the embodiment of the present invention.

FIG. 8 is a flow chart of a “display and alarm” routine executed by the microcomputer of the vehicle-mounted load measuring device according to the embodiment of the present invention.

[Explanation of symbols]

 TR, TRR, TRL Ultrasonic transducer B housing GA gear carrier assembly AH axle housing AS axle shaft SP spring 1 microcomputer 10 transmitter circuit 20 receiver circuit 100 vehicle 110 carrier 120 controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoji Nakahara 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Inventor Yasuyuki Aoki 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd. Within the corporation

Claims (1)

[Claims] 1. An ultrasonic wave transmitter / receiver which is disposed in a lower portion of a vehicle body of a vehicle, transmits ultrasonic waves substantially vertically below the vehicle body, and receives a reflected wave thereof, and an ultrasonic wave from the ultrasonic wave transmitter / receiver. An in-vehicle load measuring device, comprising: an axle housing component that houses an axle shaft that transmits a driving force to a wheel that reflects sound waves.