JPS61219830A - Apparatus for detecting angle of rotation - Google Patents

Abstract

PURPOSE:To eliminate erroneous operation due to speak surge by preventing the generation of negative voltage due to ignition noise, by providing a bias means for setting the input terminal of a voltage comparator for detecting the reference positional signal contained in an electronic circuit to predetermined potential. CONSTITUTION:When a photoelectric pick-up type sngle-of-rotation detection apparatus is constituted as an electronic circuit unit 15, the high voltage surge generated in a high voltage distribution part rides in the power source line of a battery B. A voltage comparator A1 does not take normal comparing operation by said high voltage surge and, therefore, the output of a transistor Q1, that is, the reference positional signal VREF thereof is outputted, for example, as erroneous operation noise of '1', In order to prevent said erroneous operation, the comparing reference potential f2 applied to the positive input terminal of the voltage comparator A1 is set, for example, to about 1/2 the voltage va (voltage 5V) of the power source line and, even if voltage surge is induced, the input terminal dies not become negative.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a detection device for controlling M etc. at the time of ignition of an internal combustion engine. The present invention relates to a rotation angle detection device that obtains predetermined pulse signals in synchronization.

[-5 @ Ming Background] The ignition timing of an internal combustion engine affects exhaust gas and fuel efficiency, and in order to set it optimally, a power distribution device that rotates in synchronization with the internal combustion engine is generally used, and this power distribution device is equipped with a The ignition timing is controlled by a centrifugal advance mechanism and a negative pressure advance mechanism.

However, the advance angle mechanism has poor accuracy and responsiveness due to the mechanical control method, and therefore, control methods that eliminate these drawbacks using electronic circuits have been widely adopted. When controlling with an electronic circuit, various detection devices are required, and one important detection device is a crankshaft rotation angle detection device.

As an example of this rotation angle detection device, a rotation angle detector that rotates in synchronization with the crankshaft is used. Built-in photoelectric pickup inside 6,
There is a device that extracts a predetermined pulse signal, an example of which can be found in Japanese Patent Laid-Open No. 133607/1983.

In general, the pulse signal is composed of, for example, an angular position signal that is generated 360 times during one rotation of the power distributor, and a reference position signal that is generated 4 times in a 4-cylinder engine and 6 times in a 6-cylinder engine. It is synchronized.

That is, angle signals are counted within a predetermined period of time and processed by a rotating electronic circuit, but as is well known, if a rotation angle detection device is built into the power distributor that distributes high voltage to the spark plugs,
A large surge voltage is generated when the spark plug discharges a spark.

Conventionally, in order to prevent the circuit from causing an error Ib due to this surge voltage, a surge absorbing capacitor was inserted in a part of the circuit, the signal output line was made a shielded wire, and a It requires various measures such as installing a shield plate between the power distribution section and the circuit section, which increases the cost.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a low-cost rotation angle detection device that eliminates the drawbacks of the prior art described above and is free from malfunctions caused by spark surges.

[Summary of the invention]

In order to achieve this object, the present invention provides a rotation angle detection device in which a photoelectric pickup and an electronic circuit are built into a power distribution device. It is characterized in that the negative side portion of the comparator input potential fluctuation that occurs is within the allowable common mode input voltage of the comparator.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotation angle detection device according to the present invention will be described in detail below with reference to illustrated embodiments.

Fig. 2 shows a simple embodiment of the present invention.
is the housing, and 3 is the bearing.

A first collar 4 is attached to one end of the shaft 1, and a bottle 5 is press-fitted into a 7-rank portion 4a of the collar 4. The pin 5 fits into a hole 7 provided in a 72-inch portion 6a of the second collar 6.

A rotary plate 8 is installed between the 7 rank parts 4a and 6a,
The second force 2-6 and the first collar 4 are brought into pressure contact with the stepped portion 1a of the shaft l using the screw 9, and the rotating plate 8 is pressed against both the upper and lower sides of the shaft 7.
Part 9 4a, held in @a.

The IO is a case made of synthetic resin, and is integrally molded with a connector 11 for taking out signals to the outside (see Fig. 5), and an electronic circuit formed of a hybrid integrated circuit 12 is installed in the case 10. ing. Photoelectric pickup 13
is assembled integrally with a case 10, and the case 10 is fixed to the bottom surface of the housing 2 with screws 14. Hereinafter, the combination of the hybrid integrated circuit 12 and the photoelectric pickup 13 installed in the case IO will be referred to as an electronic circuit unit 15.

FIG. 3 is a plan view showing details of the electronic circuit unit, FIG. 4 is a sectional view, and FIG. 5 is a bottom view.

The case 10 has a hole 21f: the metal bushing 28 has three holes.
The screws 14 in FIG. 2 pass through the holes.

The photoelectric pickup L3 includes a light emitting element 23 and a light receiving element 2.
4, the light emitting element 23 is installed on the holding member 22. The lead 23a of the ItS element 23 is attached to the lead frame 2.
6.27, the leads of the light receiving element 24 are attached to the lead frame 2.
7 are welded to each other.

The terminal tta of the connector 11 is welded to the lead frame 29 and electrically connected to the no-brid integrated circuit L2.

The lead frame 26, 27, 29 is, for example, a brass plate,
It is made of a material such as phosphor bronze plate, and is relatively thin so as to have good flexibility.

25 is a positioning member made of synthetic resin, and the lead 23
a * 24 a k It has a penetrating hole and holds the lead frame 26.

FIG. 5 is an exploded view showing how to assemble the one-child circuit unit 15.

The hybrid integrated circuit 12 consists of an element 12b mounted on a ceramic substrate 12a and lead frames 27 and 29. As is well known, these parts are soldered together.

A connector 11 is formed by embedding a terminal tta in the case 10, and a protrusion 31 is formed in a part.

The positioning member 25 is molded from synthetic resin, and has holes 25a, 2
5b, and a lead frame 30 is fixed thereto. The lead 23a of the light emitting element and the lead 24a of the light receiving cable pass through the hole 25a, and the protrusion 31 passes through the hole 25b. Then, the holding member 25 is fixed to the case 10 by hot caulking the head of the protrusion 31.

Next, the hybrid integrated circuit 12 is placed on the case IO and fixed with adhesive. When placed, lead frame 2
7.29 is arranged so as to be close to the lead 24a1 terminal tta of the lead 23a1 of the light-emitting element and the light receiving resistor. In the next step, they are connected by welding.

One embodiment of the electronic circuit unit 15 is shown in FIG.

23a and 24a are a light emitting element and a light receiving element, respectively, for detecting a reference position signal, and 23b and 24b are a light emitting element and a light receiving element, respectively, for detecting an angular position signal.

R1 to R, 19 are resistors, C'' to C9 are capacitors, At
, A2 is a voltage comparator, Ql is an NPN transistor, ZD
t is a Zener diode.

vl is the batch IJB, the reference position signal output end chill gF
are connected to the load resistors R1, l, the angular position signal output terminal PO8 is connected to the load resistor RL2, and Vca is a constant voltage power supply.

First, the power supply circuit will be explained. When current flows from battery B to resistor RL9, power supply line Va is set to a predetermined constant voltage by Zener diode zDl.

WIA is connected to the light emitting elements 23a and 23b via the resistor fLtt.
A stream flows through '. Light receiving cables 24a facing each other
A photovoltaic force is generated, and a current flows through the power supply line Va to the light receiving cable 24b due to the light guide effect. No. [1
The rotating plate 8 shown in the fcWr plane view is provided with a slit for detecting a reference position signal and a slit for detecting an angular position signal (not shown). A light change is applied to 24b, and a voltage is generated across the resistor R2°L1. Next, the operation will be explained with reference to the signal sequence shown in FIG.

The fc signal v1 generated across the resistance ratio 2 is applied to the voltage comparator At.
It is applied to the negative input terminal of the voltage comparator AtQ and compared with the potential v applied to the positive input terminal of the voltage comparator AtQ. The potential v2 is set to about 172 of the resistor R4,i (determined by the value of the resistor R4, 5, R3) and the power supply voltage Va.

In a region where the signal v1 is higher than the potential v2 at the 0 point, the output v3 of the voltage comparator λ1 is 0. Therefore, the reference position signal VI
IIIF becomes 11#. Furthermore, in a region where the signal Vl is lower than the potential vz, the output v3 is 6L, so the voltage is
lr is 10" 〇Resistance ratio 6 is a hysteresis resistor, which together with capacitor C2 prevents chattering of the output of voltage comparator Al. Also, capacitor Ct
This also absorbs noise applied to the positive and negative input terminals of the voltage comparator At to prevent output chattering.

The output operation of the angular position signal vpoa will be explained next.

The voltage change v4 occurring at both ends of the resistance ratio 11 is detected by the capacitor C4, and is converted into a voltage v6 that changes up and down around the potential V5 determined by the resistance ratio 12°RL3, and the negative input of the voltage comparator A2. is applied as . The positive input of voltage converter A2 has a resistance ratio of 14. RL5.几16
A suppression v7 determined by is given, and this value is set equal to the potential v5. Then, due to the voltage change v4, the output of the voltage comparator A2, that is, the angular position signal vpos
is output as a repeating signal of l'', @0''.

The resistor KR17 and the capacitors C6 and C5 prevent chattering of the voltage comparator A2 in the same way as they prevent chattering of the reference position signal voltage comparator Al. In addition, capacitors C3 and C8 are used to prevent external noise from entering the output terminals R, EF, and PO8, and capacitor C7 is used to prevent external noise from entering the power supply line Va. In order to prevent this, a capacitor C9 is inserted to prevent external noise from being applied to the power supply terminal V3.

Now, as shown in Figure 2, this detection circuit is assembled into an electronic circuit unit (1).
5, the high-voltage surge generated at the high-voltage arrangement portion lOO is transferred to the power supply line of battery B. The capacitors C9 and C7 are intended to reduce high frequency components induced by this high voltage surge, but they cannot be completely removed, and during circuit mounting, high frequency components are induced in the conductor pattern formed by the hybrid integrated circuit 12. Incoming impeda/
The high voltage comparators AL and A2 are likely to malfunction.

The above-described high voltage surge is a negative voltage surge, and a negative surge of a predetermined value or more is induced at the input terminal of the voltage comparator AI, and the voltage comparator At does not perform a normal comparison operation, so that the transistors t, The output of 2t, that is, the reference position signal vast is outputted as, for example, "L" malfunction noise.

The present invention aims to prevent this malfunction noise from occurring, and the operation in this respect will be explained below with reference to FIGS. 1 and 8.

For engine ignition timing, reference position signal VIIIF is "0"
If the spark plug malfunctions due to the spark plug discharge voltage vpti, malfunction noise V is generated.

Therefore, this malfunction noise V, is the reference position signal v■r
At the same time, J6 is also notified, so ignition timing control is not performed normally, and for example, ignition timing shifts, ignition errors, etc. occur.

In the region where the reference position signal vmxr is "0", the output signal v1 of the light receiving element 24a is necessarily 0, and the same potential as the potential at point D is applied to the negative input terminal of the voltage comparator A1, which is the next state. On the other hand, the positive input terminal of voltage comparator A1 has a potential of 0 point v.
2 is given, and since the potential at point D is higher than that, its output v3
is "l".

Now, if a high voltage surge were to enter the circuit due to the spark plug discharging, the positive and negative input terminals of the voltage comparator AI would momentarily fluctuate in the negative voltage direction. In general, a voltage comparator will not operate if the negative voltage applied to its input terminal exceeds the specified level. It takes. In addition, the limit value of this negative voltage that causes malfunction depends on temperature characteristics, for example, -0.5V at room temperature (D also (D-ri, - at L20t).
The voltage will be about 0.2V. Therefore, if the potential of the negative or positive input terminal of the voltage comparator At exceeds this negative voltage due to a high voltage surge, malfunction will occur.

In this embodiment, the comparison reference potential 'Iz'k applied to the positive input terminal of the voltage comparator At, for example, the power supply line voltage v,
(If the voltage is set to around [72] of 5VI, the input terminal will not become negative even if a voltage surge is induced.In other words, in this type of conventional circuit, the point D is grounded. Generally, the potential at the 0 point is set as high as possible, but since the output voltage of the light receiving element 24a is usually around 0.5V and the potential can only be set around O,tV, As mentioned above, it has the disadvantage of being weak against fc voltage surges.

However, according to this embodiment, the positive and negative input potentials of the voltage comparator AI are inserted into the resistor 3 in such a way that they are simultaneously shifted up in the region where the output of the light receiving element 24a is '0'. , malfunctions due to pressure surges do not occur.

Therefore, according to this embodiment, the reference position signal can always be reliably detected without requiring the various measures described above.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent malfunction of reference position signal detection due to high-voltage spark surge due to spark plug discharge without taking measures such as shielding. Since this can be sufficiently suppressed, it is possible to eliminate the drawbacks of the prior art and easily provide a rotation angle detection device that can reliably detect a reference position signal at low cost.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the Nariko circuit unit according to the present invention, FIG. 2 is a sectional view of a rotation angle detection device according to an embodiment of the present invention, FIG. 3 is a top view of the detection section, and FIG. The figure is a cross-sectional view of the detection part, FIG. 5 is an explanatory diagram of the electronic circuit unit,
FIG. 6 is an exploded perspective view of the electronic circuit unit, and FIGS. 7 and 8 are waveform diagrams for explaining the operation. 23a, zab"' light emitting element, 24a, 24b---light receiving element, 几3...resistance for bias.

Claims (1)

[Claims] 1. A shaft that rotates in synchronization with the crankshaft, a rotary plate that rotates together with the shaft, a photoelectric pick-up that detects signals from the rotation of this rotary plate, and a rotation angle detection device that includes an electronic circuit that amplifies this pick-up signal. In the device, bias means is provided to set the input terminal of the reference position signal detection voltage comparator included in the plate circuit to a predetermined potential, and the input terminal of the reference position signal detection voltage comparator is set to a predetermined potential. A rotation angle detection device characterized in that it is configured so that no negative voltage is generated.