JPS6347912Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a gear position display circuit that displays the shift position of a vehicle shift lever.

Conventionally, a common device for displaying the gear shift position of a vehicle gear shift lever is a movable contact 1 that moves on a gear shift lever (not shown), as shown in FIG.
A gear switch 3 is provided with a fixed contact 2 provided corresponding to the gear shift position, and an indicator lamp 4 independently connected to each of the fixed contacts 2 is disposed on the dash board. The display lamp 4 corresponding to the contact portion 1 is turned on to display the shift position of the shift lever. Normally, a corresponding display using a plurality of display lamps 4 can be provided at low cost with a simple circuit configuration, but in the case where various instruments and display devices are arranged on the dashboard, the gear position display device occupies a large area. This has the problem of becoming obsolete and restricting the placement of other instruments.

In order to solve these problems, a compact device has been proposed in which the gear position display is changed to a digital type, and the gear position is switched and displayed on the same display section. of
It is configured to selectively energize LEDs, etc.
Attach it to small motorcycles etc. where display surface performance is limited,
Enables display with good readability.

However, in any of the above-mentioned devices,
It is necessary to provide a plurality of independent signal lines from the gear switch to the circuit section or display section, and especially in devices with multiple gear shifting positions, it is necessary to route the number of signal lines corresponding to the number of stages.
There is a risk of failures such as disconnection, and wiring requires a great deal of effort.

In addition, in recent years, with the introduction of microcomputers, there has been an increasing demand for electronic time-sharing total control of a wide variety of instruments, and it is necessary to simplify the wiring between each device to prevent malfunctions and wiring errors caused by noise. It is said that

In response to the above-mentioned demands, the present invention aims to simplify the signal line from the detection section to the circuit section even in gear position display devices, and to provide a detection method suitable for electronic control by a microcomputer, etc.. Embodiments of the present invention will be described in detail based on the accompanying drawings.

In FIG. 2, a gear switch 3 consisting of a movable contact 1 and a plurality of fixed contacts 2 that interlock with a gear shift lever (not shown) is installed on the gear shift lever side, and the movable contact 1 is grounded. Fixed resistors 5 having the same resistance value are connected between adjacent fixed contacts 2 to form a series resistor group.

One end of the series resistor group is connected to the positive side of the power supply via a voltage dividing resistor 6, and constitutes a detection section 7 whose detection point is this connection point. The partial pressure level at the detection point in the detection unit 7 is input to the discrimination circuit 8 and processed as a discrimination signal for the contact portion of the movable contact 1. Discrimination circuit 8
has an A-D conversion function and outputs a digital drive signal to display the detected shift position of the shift lever on the digital display 9.

Now, when the gear shift lever is in the neutral position, the movable contact 1 is in contact with the fixed contact 2b,
The voltage division level at the detection point in the detection unit 7 is output as a ratio of the resistance values of the voltage division resistor 6 and all the resistance values of the series resistance group.
The discrimination circuit 8 determines it as the highest partial voltage level, and provides the A-D conversion output to the display 9. When the display 9 is constructed of a liquid crystal element, a voltage is applied to the electrode corresponding to "N" to indicate that the gear shift lever is in the neutral position. When the gear shift lever is in 3rd gear, movable contact 1 is connected to corresponding fixed contact 2.
e, the divided voltage level at the detection point in the detection unit 7 changes to the ratio of the resistance values of the voltage dividing resistor 6 and the fixed resistor 5e, and is output to the discrimination circuit 8. Discrimination circuit 8
Then, it is determined whether the divided voltage level has decreased, and a digital drive signal corresponding to this is output. Therefore, "3" is digitally displayed on the display 9, and it can be read that the gear shift lever is in the third gear.

Hereinafter, no matter which gear shift position the gear shift lever is switched to, the detection unit 7 outputs a partial pressure level corresponding to each shift position, and the current shift lever position is displayed on the display 9 by the discrimination operation in the discrimination circuit 8. is displayed.

In this way, the present invention is configured to detect the shift position of the shift lever step by step as the voltage level corresponding to each shift position, so that the signal line from the detection section 7 to the discrimination circuit 8 can be combined into one. This makes it possible to extremely simplify the wiring from the transmission side to the circuit section and the display section side, thereby reducing the occurrence of failures due to disconnection, etc., and providing a detection method suitable for electronic control. In addition, in the case of the present invention, by outputting the gear shift position as a voltage level, the A-D conversion circuit in other instruments such as fuel level gauges can be shared, and extremely good detection display can be achieved especially when time-division drive is controlled by a microcomputer. It makes it possible.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional example of a gear position display device, and FIG. 2 is a circuit diagram showing an example of a gear position display device according to the present invention. 1...Movable contact, 2...Fixed contact, 3...Gear switch, 4, 5...Resistance, 7...Detector, 8...
...Discrimination circuit, 9...Display device.

Claims (1)

[Scope of utility model registration request] A gear switch consists of a movable contact that is linked to the gear shift lever of a vehicle transmission and a plurality of fixed contacts that selectively come into contact as the movable contact moves, and a series resistance group is constructed by connecting a resistor between each adjacent fixed contact. Then, a voltage dividing resistor is connected in series to one end of the series resistor group, and a constant voltage is applied between the other end of the voltage dividing resistor and the movable contact, so that the connection point between the series resistor group and the voltage dividing resistor is a detection unit that uses voltage as a detection output;
A gear position display circuit comprising a discrimination circuit that detects the output voltage corresponding to the contact portion of the movable contact output from the detection section and outputs a display signal corresponding to the gear shift position.