JPS63179201A - Rotational angle detector - Google Patents

Abstract

PURPOSE:To cut off electromagnetic wave noises by connecting an output signal lead and a power source lead to a ground signal lead by chip capacitors respectively, and connecting a ground signal lead to a ground lead by a chip capacitor. CONSTITUTION:An electromagnetic wave noise sent through the ground signal lead 10 is discharged from a conductor pattern 22B to an ground body 4 through a chip capacitor 15, a conductor pattern 22E, a ground lead 18, and a ground terminal 26 in order. Electromagnetic wave noises sent through the power source lead 11 and output signal lead 12 are passed through conductor patterns 22A and 22C, chip capacitors 13 and 14, and conductor patterns 22B and 22D and then both passed through a capacitor 15, so that it is discharged to the earth body 4. Further, an electromagnetic wave projected on a ceramic substrate 7 is all reflected by the surface of an electric conductor wall 30. Further, an electromagnetic wave noise induced in a wire harness with the projected electromagnetic wave is all discharged to the earth body 4 through the capacitor 15. Adverse influence upon a Hall element 20, M-CI 21, etc., is eliminated to put an electronic circuit in normal operation.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention provides a rotation angle system that prevents malfunctions caused by high-frequency electromagnetic noise such as broadcast radio waves from television and radio, or ignition noise generated by a vehicle's ignition system. This invention relates to a detection device.

``Prior art'' In order to control the ignition timing, fuel injection, etc. of an internal combustion engine,
A rotation angle detection device is used that obtains a predetermined pulse signal in synchronization with the rotation of a power distributor or fuel injection pump that is linked to the crankshaft of an internal combustion engine.

In the conventional rotation angle detection device, as shown in FIG. However, when using a feed-through capacitor 3 wrapped with metal foil, a botting resin is used to fix the wire harness 1 to the ground body 4. 5, and an L-shaped fitting 6 for screwing and fixing the feedthrough capacitor 3 to the grounding body 4, and the feedthrough capacitor 3 itself is large in size, making it difficult to mount it on a vehicle. There was also the problem of increased costs.

Therefore, as shown in the exploded perspective view of FIG. 5, the rotation angle detection device using the photoelectric pickup disclosed in Japanese Patent Application Laid-Open No. 59-112205 has a ceramic substrate 7 of the electronic circuit and a photoelectric pickup at the bottom. A conductive flexible member 9 is provided between the synthetic resin case 8 equipped with the pickup 2 and the ceramic substrate 7 is grounded.
A capacitor is formed between the above conductor pattern (not shown) and the grounded member 9, and the electromagnetic wave noise on the conductor pattern is released to the ground, but the electromagnetic wave noise that once entered the electronic circuit is released to the ground. Therefore, there is a problem in that it is not possible to reliably prevent interference from electromagnetic noise. In addition, when the Hall element is provided on the ceramic substrate 7, if a conductive visibility member 9 is provided between the ceramic substrate 7 and the synthetic resin case 8, the rotating magnet and the Hall element can be placed outside the case 8. As the distance from the magnet increases, the magnetic flux of the magnet is blocked by the conductive member 9, and the output of the Hall element decreases significantly.

"Problems to be Solved by the Invention" The present invention has been made to solve the above problems. The purpose is to provide a detection device.

"Means for Solving the Problem" According to the present invention, an output signal lead, a power supply lead, and a ground signal lead are led out from a ceramic substrate of an electronic circuit, and are provided at the entrance of the ceramic substrate. The output signal lead and the power supply lead are respectively connected to the ground signal lead by the first and second chip capacitors, and the ground lead connected to the ground body is led out from the ceramic substrate, and the ground lead is connected to the ground signal lead. There is provided a rotation angle detection device characterized in that the ground signal lead is connected to the ground lead by a third chip capacitor provided at the inlet.

"Operation" According to the above configuration, electromagnetic wave noise carried on the output signal lead and the power supply lead is dropped to the ground signal lead through the first and second chip capacitors, and is further passed through the third chip capacitor and the ground lead. It escapes to the ground object.

"Example" Next, an embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1(1), a ceramic substrate 7 is provided inside the synthetic resin case 8. As shown in FIG.

A Hall element 20 that serves as a magnetic detection element is formed on the ceramic substrate 7, and an M-I that makes up an electronic circuit is formed.
A C (medium scale integrated circuit) 21 is formed. Further, conductor patterns 22A to 22E are formed on the ceramic substrate 7, and between the ground signal lead 10 and the power supply lead 11, the conductor pattern 22A and the chip capacitor 1
3 (C1) and the conductor pattern 22B.

Between the output signal lead 12 and the ground signal lead 10,
The conductor pattern 22C, the chip capacitor 14 (C2>) and the conductor pattern 22D are connected to each other.The conductor pattern 22B, the chip capacitor 15 (C3) and the conductor pattern 22E are connected between the ground signal lead 10 and the ground lead 18. Therefore, the connections shown in the equivalent circuit of FIG. It is directly soldered to the conductor patterns 22A to 22E.

Terminals 23A and 23B are connected to the M-IC 21 by conductors (not shown) at the bottom of the ceramic substrate 7.
, 23C are provided, and these terminals 23A to 2
Connections between 3C and leads 10 to 12 are made by soldering or welding. The leads 10 to 12 and the conductor patterns 22A to 22E are connected by soldering, and the wire harness 1 is connected to the leads 10, 11, and 12. The grounding lead 18 is connected to a grounding terminal 26 that is brought into contact with a grounding body 4 such as an internal combustion engine block or a vehicle chassis when installed on a vehicle. A rotating magnet 28 faces the lower surface of the synthetic resin case 8, and the Hall element 20 generates a voltage in a direction perpendicular to the magnetic flux generated by the rotating magnet 28 and the current flowing through the Hall element 20. 8 is covered with a rotating magnet 28 by an electrical conductor wall 30 such as a housing of a power distributor and a partition plate in the housing, or a housing of a fuel injection pump. Chip capacitor 13~
The capacitance of 15 is relatively large, and the conductor pattern 22
A to 22E are made thicker and shorter, and terminals 23A to 23C
In addition, the grounding terminal 26 has a wide contact area with the grounding body 4, and the high frequency impedance of the path through which electromagnetic noise is released is reduced.

"Operation" According to the above configuration, the chip capacitor 13.
Since 14.15 has a very small impedance, the electromagnetic noise that comes on the ground signal lead 10 is transferred from the conductor pattern 22B to the chip capacitor 1.
5→conductor pattern 22E→ground lead 18→ground terminal 26 to escape the ground body 4/\. Furthermore, the electromagnetic noise carried on the power supply lead 11 is removed by the conductor pattern 2.
From 2A to chip capacitor 13 → conductor pattern 22B →
Chip capacitor 15 → conductor pattern 22E-4m ground I
J-)'18-Grounding 9-Escaped to the grounding body 4 through the mill 26. Furthermore, the electromagnetic wave noise coming to the output signal lead 12 is transmitted from the conductor pattern 22C to the chip capacitor 14 → the conductor pattern 22D → the chip capacitor 1.
5→conductor patterns 2, 2E→ground lead 18→ground terminal 26 to escape to the ground body 4.

In addition, the electromagnetic waves directly irradiated toward the ceramic substrate 7 are all reflected on the surface of the electrical conductor wall 3o and do not penetrate into the interior of the electrical conductor wall 3o. The electromagnetic noise (that is, high frequency current) that is induced and comes on the ground signal lead 1o, power supply lead 11, and output signal lead 12 is all bypassed via the chip capacitor 15 through the above-mentioned path, and is connected to the ground body 4. is forced to escape. Here, the electrical conductor of the chip capacitor 15! ! Grounding terminal 2 on the 3o side
6 and the ground lead 18 are not directly connected to the ground signal lead 10, but are connected through the impedance provided by the capacitor 15. Therefore, electromagnetic wave noise is caused by the Hall element 20 and the M-IC 21, etc., to ground the electronic circuit. It does not flow into the signal lead 10, therefore,
High-frequency electromagnetic noise that has entered the wire harness 1 is prevented from having an adverse effect on the Hall element 20, the M-IC 21, etc., and the normal operation of the electronic circuit is ensured.

“Numerical performance example” Electromagnetic wave resistance characteristics (so-called E
The test results of the electromagnetic wave test cell (T 8M cell) are shown in Figure 3 to show the MI characteristics. In Figure 3, the vertical axis represents the electric field strength and the horizontal axis represents the frequency. ,
In the case of a rotation angle detection device having no conductor pattern 22E, chip capacitor 15 (C3), ground lead 18, and ground terminal 26, as shown in FIG. The electric field strength is 100 (V/-
FIIF due to electromagnetic noise may occur before the field strength reaches
Even when the voltage reaches 0 (V/m), electromagnetic noise interference does not occur and the EMI characteristics do not improve.

The rotation angle detection device of this embodiment is the first one? Compared to the comparative example shown in the figure, the chip capacitor 15. Only three parts, the ground lead 18 and the ground terminal 26, have been added, and the conductor pattern 22E is connected to the other conductor pattern 22A 22D.
At the same time, it can be formed on the ceramic substrate 7, and the size of the ceramic substrate 7 is also 15.5 mm as in the comparative example.
Good EMI characteristics were obtained at a relatively low cost by taking measures such that the dimensions were only slightly increased from 17 mm to 13 mm.

"Effects" As described above, the device of the present invention has the above configuration, and in a rotation angle detection device having a Hall element, the ground signal lead is connected to the internal combustion engine block or vehicle chassis through a capacitor. Since it is connected to a grounding body such as a grounding body, it is possible to reliably prevent interference from electromagnetic noise, and since the capacitor connecting the grounding signal lead and the grounding body is composed of a chip capacitor, it can be made smaller. It has excellent effects such as:

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are front views and equivalent circuit diagrams transparently showing examples of the present invention, FIG. 2 is a front view showing a comparative example, and FIG. 3 is a characteristic diagram showing test results. 4th [IQ(u)
, (b) is a front view and an equivalent circuit diagram showing the conventional technology,
FIG. 5 is an exploded perspective view showing another prior art. 41. , grounding body, 711. Ceramic substrate, 88.
. Synthetic resin case, 10, Ground signal lead,
11. Power lead, 12. ,,output signal lead, 13,14,15. ,,Chip capacitor, 18, ,Ground lead, 20, ,Hall element,
21,,,M-IC122A~22E,,,Conductor pattern,23A~23C,,,Terminal,2
611. Ground terminal, 28. ,,Rotating magnet,30,,,Electric conductor wall.

Claims (1)

[Claims] A Hall element that detects a signal in synchronization with the rotation of the crankshaft, and an electronic circuit that amplifies the signal of the Hall element, the Hall element and the electronic circuit are integrated into a ceramic substrate and synthesized. In the rotation angle detection device housed in a resin case, an output signal lead, a power supply lead, and a ground signal lead are led out from the ceramic substrate, and first and second chip capacitors are provided at the entrance of the ceramic substrate. The output signal lead and the power supply lead are respectively connected to the ground signal lead, and the ground lead connected to the ground body is led out from the ceramic substrate, and the third chip is provided at the entrance of the ceramic substrate. A rotation angle detection device characterized in that a ground signal lead is connected to a ground lead by a capacitor.