JPS6228506Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a gear shift position indicator in an automobile transmission.

BACKGROUND ART Conventionally, when changing gears in an automobile, the gear shift position of the transmission is confirmed by the position of the shift lever.

Purpose The present invention was developed with these points in mind, and is a gear shift position system that electrically detects the gear shift position in an automobile transmission and displays the position digitally on an LCD. It provides an indicator.

Configuration The gear shift position indicator according to the present invention uses a general 7-segment LCD driver to display gear shift positions "1", "2", "3", "4", and "5" on the LCD. In addition to displaying numerical values such as , etc., measures are taken to display "N" for the neutral gear shift position, and the gear shift position is not displayed when the system is in a half-neutral state before entering neutral. It is distinctive in that it takes such measures. Note that when a 7-segment LCD is used to display numerical values, it is normally only possible to display numbers from "0" to "9", but in this invention, the LCD is
It has a segment configuration (see Figure 2), and by using a general 7-segment LCD driver, the neutral gear shift position is displayed as "N" instead of "0". .

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the gear shift position indicator according to the present invention, as shown in FIG. and bridge diodes D1 to D4 that convert the output signals of the gear shift position detection switches for 1st to 5th speeds in the switch group SW1 into binary codes.
a decoder/driver 2 that reads the BCD output and outputs 7-segment signals a to g according to the on/off state of each gear position detection switch for 1st to 5th gears.
and diodes D5 to D which detect an error and issue a BLANK command to the decoder/driver 2 when the BCD output and the output of the neutral N detection switch in the switch group SW1 are both at low level.
8. Error detection circuit 3 (NOR circuit) consisting of resistor R2 and inverter INV, and switch group SW1
The output of the neutral N detection switch in , the a output, the d output of the decoder/driver 2, and the clock given to the decoder/driver 2 are each exclusive OR'ed, and the 9 segments a to i are calculated.
A circuit consisting of XOR1 to XOR3 that outputs LCD drive signals, and a 9-segment main transmission liquid crystal display element LCD1 (see Figure 2)
It is composed of:

In addition, if the vehicle is equipped with a sub-transmission that switches between high-speed and low-speed dual ranges, the high-speed H and low-speed L range positions of the sub-transmission can be changed as shown in the figure. Exclusive OR of the non-bridge type switch group SW2 to be detected, the output of each of its range position detection switches H and L, and the output of the OR circuit 6 which ORs these respective outputs, and the clock. 3 segments j, k, l
XOR4 to XOR6 outputs the LCD drive signal of
(This circuit and the OR circuit constitute a 3-segment LCD driver) and a sub-transmit driven by drive signals for the 3 segments j, k, and l. A liquid crystal display element LCD2 (see FIG. 2) for display is provided as necessary. In FIG. 1, 4 indicates a power supply circuit, and 5 indicates a clock generation circuit.

Also, for primary and secondary transmission
LCD1 and LCD2 are made into one chip as shown in Fig. 2, and the LCD1 part consists of nine segments a to i, "N", "1", "2",
In order to be able to display each of "3", "4", and "5", the second part of the LCD should be made up of three segments j to l to display each of "H" and "L". It is becoming possible to do this. In addition, switch groups SW1 and SW2 detect the shift positions of the main and sub transmissions, respectively.
For example, the drive shaft's neutral or gear shift position from 1st to 5th gear or high speed in each transmission,
A rotary switch or the like is used in which each corresponding switch contact is turned on depending on the low speed range position. In addition, each of these switch groups SW
SW1 and SW2 are non-bridge types, and two or more switch contacts will not be on at the same time, but in an uncertain half-neutral state, all switch contacts will be off.

In the gear shift position according to the present invention configured as described above, when the main transmission is shifted to the neutral position and the neutral N detection switch in the switch group SW1 is turned on (at this time, the decoder/driver 2 is set so that its a to f outputs are “1” and its g output is “0” so that “0” is displayed), and the output of decoder/driver 2 at that time is
By the output of the circuit consisting of XOR1 to XOR3
“N” is displayed on LCD1. Also, when shifted to each position from 1st to 5th gear, each corresponding switch contact is turned on,
``1'', ``2'', ``3'', ``4'', and ``5'' will be displayed on LCD 1 according to the output of decoder/driver 2, regardless of the circuit consisting of XOR1 to XOR3. . Furthermore, when in the half-neutral state, all switch contacts in the switch group SW1 are in the OFF state, which is detected by the detection circuit 3 and the decoder/driver 2
BLANK pin becomes high level, which causes
LCD1 becomes BLANK (no display). The driver can know that the main transmission is in a half-neutral state because the LCD 1 is in the BLANK state. FIG. 3 shows a table of the on/off states of the switch group SW1, the signal states of segments a to i of the LCD 1, and the display states of the LCD 1 when displaying each gear shift position in the main transmission. There is.

As for the sub-transmission, when it is shifted to the high-speed H side range position, the detection switch H in the switch group SW2 is turned on and "H" is displayed on the LCD 2. Similarly, when shifted to the low speed L side range position, the detection switch L in switch group SW2
is turned on and "L" is displayed on the LCD 2.
Furthermore, when the sub-transmission is in a half-neutral state, segments j to
Both of l become "0" and the LCD 2 goes into a BLANK state, allowing the driver to know that the auxiliary transmission is in a half-neutral state. FIG. 4 shows a table of the on/off states of the switch group SW2 in the sub-transmission, the signal states of the j to l segments of the LCD 2, and the display state of the LCD 2.

FIG. 5 shows another embodiment of the gear shift position indicator according to the present invention, in which case it is used as a switch to detect each of the gear shift positions of the 1st to 5th gears of the main transmission, for example, to produce a BCD output. Using a binary code switch SW3 such as a Samir switch, its BCD output can be used as a 7-segment decoder/
Directly drive driver 2 to display “1” on LCD 1,
In addition to displaying ``2'', ``3'', ``4'', and ``5'', the photointerrupter is also used to prevent BCD output from being generated from the switch SW3 even in the half-neutral state. An angle detection sensor 7 is provided to detect that the main transmission is in a half-neutral state, and its detection output forces the decoder/driver 2 to enter a BLANK state. In addition, at the neutral N shift position, all of the switch contacts A, B, and C of the binary code switch SW3 are in the OFF state, and the A, B ,C and
When each BLANK signal is at low level, the output of the NOR circuit 8 causes XOR1 to XOR
“N” is applied to LCD1 as described above through the circuit No.3.
is displayed.

However, with this configuration, compared to the embodiment shown in FIG. 1, it is necessary to convert the switch output for detecting the gear shift position of the main transmission into BCD using the BCD conversion circuit 1. This means that the circuit configuration can be simplified.

Effects As described above, the gear shift position indicator according to the present invention includes a switch means for detecting each gear shift position of the transmission, and a BCD signal of the gear shift position detected by the switch means. a decoder/driver for causing the LCD to display numerical values; a means for converting a 0 display signal outputted from the decoder/driver to the LCD into an N display signal in response to a neutral position detection signal from the switch means; This system consists of a means for detecting the half-neutral state of the decoder/driver and forcing the decoder/driver to go into a blank state. It has excellent advantages.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing an embodiment of the gear shift position indicator according to the present invention, Fig. 2 is a diagram showing the segment configuration of the LCD in the same embodiment, and Figs.
FIG. 5 is an electric circuit diagram showing another embodiment of the present invention. 1... BCD conversion circuit, 2... Decoder/driver, 3... Switch state detection circuit, 4... Power supply circuit, 5... Clock generation circuit, 6... OR circuit, 7... Angle detection sensor, 8 ...NOR circuit, SW1, SW3 ... Main transmission gear shift position detection switch group, SW2
...A group of switches for detecting the range position of the sub-transmission.

Claims (1)

[Scope of utility model registration request] a switch means for detecting each gear shift position of the transmission; a decoder/driver for causing a numerical display to be displayed on an LCD in accordance with a BCD signal of the gear shift position detected by the switch means; A means for converting a 0 display signal outputted from a decoder/driver to an LCD into an N display signal in response to a neutral position detection signal, and a means for detecting a half-neutral state of the transmission and forcibly operating the decoder/driver. and means for blanking the gear shift position indicator.