JPH06331636A - Vehicle odometer - Google Patents

Abstract

PURPOSE:To provide a vehicle odometer that does not require a transmitting portion for transmitting a signal indicating detection of the magnetism of a magnet. CONSTITUTION:A ferromagnet 5 is attached to one of the spokes 4a of a front wheel 4 and magnetism emanating from the magnet 5 is detected by a sensor coil in a meter main body 1 secured to a handle bar 3 above the front wheel, to count the number of turns of the front wheel. Magnetic lines of force emanating from the magnet 5 are pointed in the radial direction of the front wheel, and a sensor coil having directivity is used with the magnetism detecting area of the sensor coil set to cover the upper side of the front wheel 4. Since the magnetism of the magnet 5 can be directly detected by the sensor coil attached to the meter main body 1, the constitution of the meter can be simplified and the meter can be installed very easily compared to conventional methods.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle running meter for displaying a running speed or a running distance.

[0002]

2. Description of the Related Art In recent years, the popularity of bicycles has increased, and more and more people are using bicycle meters for displaying the traveling speed or traveling distance of bicycles.

As such a meter for a bicycle, a magnet is attached to the spokes of the front wheels of the bicycle, a reed switch is attached to a fork supporting the front wheel, and the magnet passes near the reed switch as the front wheel rotates. A bicycle meter that sometimes turns on the reed switch and transmits the on / off state of the reed switch to the meter body attached to the handlebar via a signal line to count the number of rotations of the front wheel is known. ing.

However, this meter has a problem that the work of setting the fixed position of the reed switch and the work of wiring the signal line are troublesome and that the signal line is easily broken by the rotation of the handle.

As a bicycle meter that solves this problem, for example, a bicycle speed display device disclosed in Japanese Patent Application Laid-Open No. 3-20669 is known. This bicycle meter is provided with a frame supporting a wheel of a bicycle, magnetic detection means for detecting a magnet attached to the wheel, and a transmission section for wirelessly transmitting a detection signal of the detection means. A receiving unit that receives a signal from the transmitting unit, a calculating unit that calculates a traveling speed from a signal received by the receiving unit, and a traveling speed are displayed on a main body case attached to a front position of a driving vehicle such as a bar. And a display device.

According to the above configuration, when the magnetism of the magnet that moves with the rotation of the wheel is detected by the magnetic detection means (for example, the reed switch), this detection signal is wirelessly transmitted by the transmission section. The detection signal wirelessly transmitted is received by the reception unit, and the traveling speed is calculated by the calculation unit based on the received detection signal,
Displayed on the display.

As a result, it is not necessary to wire the signal line from the front wheel side portion to the handlebar, and the bicycle user can easily know the running speed without causing the signal line to be disconnected.

[0008]

However, in the latter conventional bicycle meter described above, since the reed switch and the transmission section, which are magnetic detection means, must be mounted near the wheels, the structure of the apparatus is complicated. In addition, handling the setting of the reed switch mounting position was very troublesome.

In view of the above problems, an object of the present invention is to provide a vehicle running meter that does not require a transmitter for transmitting a magnetism detection signal of a magnet.

[0010]

In order to achieve the above object, the present invention is a vehicle running meter for displaying a running speed or a running distance of a vehicle, which is provided at a predetermined position of a wheel of the vehicle. A magnet and a meter main body attached to a position visible to the driver of the vehicle. The meter main body includes a magnetic detector for detecting the magnetism of the magnet, a clock signal generating circuit, a display, and An arithmetic circuit for calculating the traveling speed or traveling distance based on the clock signal output from the clock signal generating circuit and the magnetic level of the magnet detected by the magnetic detector, and displaying the traveling speed on the display. We propose a vehicle running meter.

[0012] According to a second aspect of the invention, there is proposed a vehicle travel meter according to the first aspect, wherein the magnet is made of a rare earth metal.

[0012]

According to the present invention, the magnetism emitted from the magnet attached to the wheel is detected by the magnetic detector provided in the meter body. At this time, the magnetic detector detects magnetism whose level changes according to the distance between the magnet and the magnet. Further, based on the clock signal output from the clock signal generation circuit and the magnetic level detected by the magnetic detector, the arithmetic circuit performs arithmetic processing for calculating the number of rotations of the wheel per unit time, and the like. The traveling speed or traveling distance of the vehicle is calculated and displayed on the display.

According to the second aspect of the present invention, the magnet made of a rare earth metal has a magnetic flux density which is about 3 to 10 times that of a ferrite magnet in the same size. It is possible to obtain sufficient magnetic force.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a block diagram showing an embodiment of the present invention, FIG.
(a) and (b) are configuration diagrams showing a meter main body of one embodiment.
2B is a sectional view taken along the line AA of FIG. 2A.

In the figure, reference numeral 1 denotes a meter main body, which is attached to a central portion of a handlebar 3 of the bicycle main body 2 and just above a front wheel 4. 5 is a ferromagnetic magnet (hereinafter referred to as a magnet), which is made of, for example, a rare earth metal,
It has a magnetic flux density of 0 Gauss and is attached to the spokes 4a at the outer peripheral portion of the front wheel 4.

The meter main body 1 has a housing 11 formed of a synthetic resin or the like in a cylindrical shape. As shown in FIG. 2, a display window 11a is provided on the peripheral surface of the housing 11 and one end portion in the longitudinal direction is provided. Has a battery lid 11b and the switch knob 11 on the other end.
c and 11d are provided respectively. Furthermore, the housing 1
1, the battery 12 is arranged inside the battery lid 11b, the rotary switch 13a and the push switch b are arranged inside the switch knob 11c, and the printed board 14 is arranged in parallel with the display window 11a.

A liquid crystal display (hereinafter referred to as a display) is provided on the surface of the printed board 14 so as to face the display window 11a.
15, a sensor coil 16 having a ferrite core of about 300 mH to 500 mH and an electronic component 17 forming an electric system circuit are arranged on the back surface. Here, the meter main body 1 is arranged such that the central axis of the sensor coil 16 faces the center of the front wheel 4, and the magnet generated from the magnet 5 can be taken into the magnetic detection range MD of the sensor coil 16.

FIG. 3 is a block diagram showing an electric circuit in one embodiment. In the figure, 5, 15, and 16 are the magnets, the display and the sensor coils described above, and 21 is
An amplifier having an amplification degree of about 40db to 60db, 22 is a low-pass filter, 23 is a pulse shaping circuit, 24 is a clock signal generating circuit, and 25 is an arithmetic processing circuit including a CPU.

Both ends of the sensor coil 16 are connected to an amplifier 21.
The voltage induced in the sensor coil is amplified by the amplifier 21 and output. Amplifier 21
After the high-frequency noise is removed by the low-pass filter 22, the voltage output from is input to the pulse shaping circuit 23. The pulse shaping circuit 23 generates a rectangular wave pulse signal for each rotation of the front wheel 4 based on the input signal,
Output to the arithmetic processing circuit 25.

Here, the low-pass filter 22 is set to a pass band capable of passing only the frequency of the pulse signal obtained by rotating the magnet 5 and removing radio waves and external noise. The pulse shaping circuit 23 is composed of a polarity determination circuit 23a and a fall detection circuit, and the front wheel 4
One pulse signal is output for each one rotation. That is, the polarity determination circuit 23a includes, for example, the diodes 231,232, the amplifiers 233,234, the NOT circuit 235, and the R circuit.
-S flip-flop 236, only the positive pulse signal output from the low pass filter 22 is input to the S (set signal) input terminal of the RS flip-flop 236, and only the negative pulse signal is inverted to R- It is input to the R (reset signal) input terminal of the S flip-flop 236. Further, the output terminal Q of the RS flip-flop 236 is connected to the input terminal of the fall detection circuit 23b, and the fall detection circuit 23b receives the input signal TS (R-
When the falling edge of the output signal of the S flip-flop 236) changing from the high level to the low level is detected, the positive pulse signal PS having a predetermined width is output.

The clock signal output from the clock signal generation circuit 24 is input to the arithmetic processing circuit 25. Further, the arithmetic processing circuit 25 is connected to the rotary switch 13a, the push switch 13b, and the display unit 15 so that each switch signal can be input and the arithmetic processing result can be displayed on the display unit 15.

Next, the operation of this embodiment having the above-mentioned structure will be described. After the meter is attached to the bicycle, the diameter of the wheel is first set in the arithmetic processing circuit 25. This setting is performed using the rotary switch 13a and the push switch 13b.

When the bicycle is running, the magnets 5 attached to the spokes 4a rotate as the front wheels 4 rotate, and when the magnets 5 pass through the upper part of the front wheels, that is, the position closest to the sensor coil 16, the sensor coil An induced electromotive force is generated in 16.

From the sensor coil 16, when the magnet 5 passes through the position A closest to the sensor coil 16 by Lenz's law as shown in FIG. 4, a pair of positive and negative pulses as shown by P1 in FIG. When a signal is output and the magnet 5 passes through the position B farthest from the sensor coil 16, the sensor coil 16 outputs a pair of positive and negative pulse signals whose polarities are opposite to those described above as indicated by P2 in FIG. To be done.

The induced electromotive force generated in the sensor coil 16 is amplified by the amplifier 21, and the low-pass filter 2
2 is input to the pulse shaping circuit 23. here,
The high-frequency noise component superposed on the output signal of the amplifier 21 is removed by the low-pass filter 22, and the output signal of the low-pass filter 22 is only the component of the induced electromotive force generated in the sensor coil 16.

In the pulse shaping circuit 23, the RS flip-flop 236 is set by the positive pulse signal input from the low pass filter 22 to set its output signal to the high level, and the negative pulse signal R The S flip-flop 236 is reset and its output signal is set to the low level. Therefore, the pulse shaping circuit 23 detects a combination of pulse signals when the magnet 5 passes through the position A closest to the sensor coil 16 and outputs one positive pulse signal. As a result, one positive pulse signal is output from the pulse shaping circuit 23 every time the front wheel 4 makes one revolution, and this pulse signal PS is input to the arithmetic processing circuit 25.

The arithmetic processing circuit 25 is a pulse shaping circuit 23.
The pulse signal PS output from is detected, the total number of pulses is counted, and the number of pulses per unit time is counted. Further, the arithmetic processing circuit 25 multiplies the total number of counted pulses by the circumference of the front wheel 4 to calculate the traveling distance, and multiplies the counted number of pulses per unit time by the circumference of the front wheel 4 to determine the traveling speed. The calculated distances and the traveling speeds are displayed on the display unit 15.

As described above, in this embodiment, since the ferromagnetic magnet 5 made of a rare earth metal and the sensor coil 16 having a sharp directivity are used, the magnetism of the magnet 5 attached to the spokes 4a of the front wheel 4 is measured by the meter body 1. It can be directly detected by the sensor coil 16 attached to the. As a result, the structure of the bicycle travel meter can be simplified, and the meter can be attached very easily as compared with the related art.

In this embodiment, the traveling distance and the traveling speed are calculated and displayed, but the present invention is not limited to this, and only the traveling speed may be displayed.
It goes without saying that other information, such as the time, may be displayed.

In this embodiment, the ferromagnetic magnet made of rare earth metal is used, but the present invention is not limited to this.

Furthermore, in the present embodiment, the present invention is applied to a running meter for bicycles, but the present invention is not limited to this, and the same applies when applied to running meters for automobiles, motorcycles, or snowmobiles. The effect can be obtained.

[0032]

As described above, according to the first aspect of the present invention, the magnet is attached to the wheel of the vehicle and the magnetism generated by the magnet is detected by the magnetic detector provided in the meter body. Therefore, as compared with the prior art, the device configuration is much simpler and the handling is easier, which is a very excellent effect.

Further, according to the second aspect, in addition to the above effects, since the magnet shape is small and a high magnetic flux density can be obtained, the magnet can be easily attached to any place. Even if the distance between the magnet and the main body is increased, the rotation of the magnet can be accurately detected, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a meter body of one embodiment.

FIG. 3 is a block diagram showing an electric system circuit according to an embodiment.

FIG. 4 is a diagram for explaining a rotation detecting operation of a front wheel in one embodiment.

FIG. 5 is a signal waveform diagram for explaining a rotation detecting operation of a front wheel in one embodiment.

[Explanation of symbols]

1 ... Meter body, 2 ... Bicycle body, 3 ... Handlebar, 4 ... Front wheel, 4a ... Spoke, 5 ... Ferromagnetic magnet, 11 ... Housing, 11a ... Display window, 11b ... Battery cover, 1
1c, 11d ... switch knob, 12 ... battery, 13a ...
Rotary switch, 13b ... Push switch, 14
... Printed circuit board, 15 ... Indicator, 16 ... Sensor coil, 17 ... Electronic component, 21 ... Amplifier, 22 ... Low pass filter, 23 ... Pulse shaping circuit, 23a ... Polarity determination circuit, 231, 232 ... Diode, 233, 234 ... Amplifier, 235 ...
NOT circuit, 236 ... RS flip-flop, 23b ...
Fall detection circuit, 24 ... Clock signal generation circuit, 2
5 ... Arithmetic processing circuit.

Claims (2)

[Claims] 1. A vehicle traveling meter for displaying a traveling speed or a traveling distance of a vehicle, the magnet being provided at a predetermined position of a wheel of the vehicle, and a meter mounted at a position visible to a driver of the vehicle. The meter body includes a magnetic detector for detecting the magnetism of the magnet, a clock signal generation circuit, an indicator, a clock signal output from the clock signal generation circuit, and the magnetic detector. A traveling meter for a vehicle, comprising: an arithmetic circuit that calculates the traveling speed or traveling distance based on the detected magnetic level of the magnet and displays the traveling speed or traveling distance on the display. 2. The vehicle running meter according to claim 1, wherein the magnet is made of a rare earth metal.