JP2574087Y2 - Position detection device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device such as a throttle position sensor, and more particularly to a structure for preventing a migration phenomenon occurring near a terminal.

[0002]

2. Description of the Related Art Conventionally, as a throttle position sensor for detecting the opening of a throttle valve, two brushes fixed to a rotor interlocking with the opening and closing operation of the throttle valve are printed on a base 30 of the element shown in FIG. There is one that slides on each of the resistors 31 and 32 and outputs a voltage corresponding to the opening of the throttle valve.

In such a throttle position sensor, a DC voltage applied to a resistor 31 conducting to an input terminal 33 is supplied from one brush sliding on the resistor 31 to a resistor conducting to an output terminal 34. The signal is output to the output terminal 34 via the other brush sliding on the body 32. The voltage value output at this time is determined by the resistance values of the resistors 31 and 32 and is directly proportional to the position of the brush with respect to the resistors 31 and 32, that is, the position in the rotation direction of the rotor.

The resistors 31 and 32 and the terminals 33 and 34 are
As shown in FIG. 6, an electrode film 35 provided on a base 30 is provided.
Conducts through. The electrode film 35 contains silver,
The portion other than the portion covered by the terminal 33 or 34 is exposed to air.

[0005]

In the conventional throttle position sensor described above, the electrode film 35 containing silver is used.
However, since a portion other than the portion covered by the terminals 33 and 34 is exposed to air, when a DC voltage is applied to the electrode film 35, a migration phenomenon occurs near the anode, and the gap between the adjacent terminals 33 and 34 is generated. A short circuit may occur. That is, when a DC voltage is applied to the electrode film 35 exposed to the air, silver contained in the electrode film 35 elutes to generate and precipitate silver hydroxide, or to form colloidal silver, and to form these hydroxides. Silver or colloidal silver is used as a conductor and the terminal 3
There is a possibility that a short circuit between the terminals 3 and 34 may occur.

When a short circuit occurs between the terminals 33 and 34 due to the occurrence of such a migration phenomenon, as shown in FIG. 7, the output voltage value with respect to the brush movement amount of the throttle position sensor becomes a normal value shown by a solid line in the figure. There is a problem that the output voltage value in the state is shifted as shown by a broken line in the figure.

The present invention provides a position detecting device which can surely prevent a short circuit between terminals due to a migration phenomenon and can thereby maintain a normal relationship between a moving amount of a sliding member and an output voltage value. It is intended to provide.

[0008]

A position detecting device according to the present invention is a position detecting device for detecting a position of an object to be detected by outputting a voltage corresponding to a conduction position of two resistors, An electrode film conducting to each resistor and containing silver,
A terminal attached to the electrode film with a first protective film, the terminal being electrically connected to the resistor via the electrode film, at least a part of the outer surface of the electrode film is covered with the terminal and the first protective film, and It is characterized in that portions other than the terminal and the portion covered with the first protective film are covered with the second protective film.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
FIG. 1 is a view showing an element of a throttle position sensor according to an embodiment of the present invention, and a mounting portion of a terminal 13 is a cross-sectional view taken along a line BB in FIG. In this figure,
A first resistor 12 that is connected to an input terminal 11 and a second resistor 14 that is connected to an output terminal 13 are printed on a base 10 made of ceramic or the like. A DC voltage applied from a power supply (not shown) to the first resistor 12 via the input terminal 11 passes through an input brush and an output brush (not shown) fixed to a rotor (not shown) in a state where they are electrically connected to each other. 2 resistor 14. The rotor rotates around a printing center O of the first and second resistors 12 and 14 in conjunction with a throttle valve (not shown).

Input / output terminals 11, 13 and ground terminal 1
As shown in FIGS. 2 and 3, each of the reference numerals 5 is attached to the upper surface of the electrode film 16 by the solder 17 in a state of being covered with a solder 17 as a first protective film. Conduction to the bodies 12, 14 (FIG. 1). Joint between electrode film 16 and solder 17 and electrode film 1
6 is covered with a resistance film 18 which is a second protective film. The electrode film 16 is provided on the substrate 10 and contains silver. The outer surfaces of the solder 17 and the resistive film 18 are covered with a polytetrafluoroethylene resin (PTFE) film or a silicon resin film 19 as a third protective film having water repellency. A predetermined gap A (see FIG. 1) is provided between the resistive films 18 of the adjacent input / output terminals 11 and 13.
And FIG. 3) is ensured, whereby a short circuit between the input / output terminals 11 and 13 is prevented by the resistance film 18 which is a conductor.

In this embodiment, the DC voltage applied from the power supply to the input terminal 11 is applied to the first resistor 12 and the input brush slides on the first resistor 12. Is applied to the second resistor 14 on which the output brush slides via the output brush, and is output to the output terminal 13. The voltage value output at this time is determined by the resistance values of the first and second resistors 12, 14, and is determined by the position in the rotation direction of the first and second brushes, that is, the rotation direction of the rotor linked to the throttle valve. Directly proportional to position.

Next, a method of assembling the element of this embodiment will be described. First, the terminals 11, 13 are connected to the resistor 12,
A solder 17 is attached to the upper surface of the electrode film 16 provided on 14. At this time, the terminals 11, 13, 15
And the upper surface of the electrode film 16 are covered with the solder 17. Next, the side surfaces of the electrode film 16 and the solder 17 are covered with a resistance film 18, and the outer surfaces of the solder 17 and the resistance film 18 are further covered with a PTFE film or a silicon resin film 19. Thereby, the electrode film 1
6 is placed in a state where the outside air is shut off.

As described above, according to the above-described embodiment, the terminals 11, 13, and 15 are attached to the electrode film 16 by the solder 17, and the attachment portions and the electrode film 16 are attached.
Is covered with a resistive film 18 and solder 17
Since the outer surface of the resistance film 18 is covered with a PTFE film or a silicon film, the silver contained in the electrode film 16 is not exposed to air, so that silver hydroxide or colloidal silver is provided near the terminals 11 and 13. The occurrence of the migration phenomenon that precipitates can be reliably prevented. As a result, a short circuit between the adjacent terminals 11 and 13 is reliably prevented, and the relationship between the movement amount of each brush and the output voltage value can be normally maintained.

In the above embodiment, the second protective film is the resistive film 18 and the resistive film 18 of each of the terminals 11 and 13 is formed.
Although a predetermined gap A was secured between them, as shown in FIG.
The insulating film 20 may be used instead of the resistance film 18 as the second protective film. According to this, a short circuit between the terminals 11 and 13 is reliably prevented without securing a gap between the insulating films 20 of the terminals 11 and 13.

In the above embodiment, each of the terminals 11, 13,
15 is covered with the solder 17 and the electrode film 16
, So that each terminal 11, 13,
15 does not directly contact the electrode film 16, but each terminal 11,
The bonding surfaces of the electrodes 13 and 15 with the electrode film 16 are
The terminals 11, 13, and 15 may be configured so as to be in direct contact with the electrode film 16 without being covered.

[0016]

As described above, according to the present invention, it is possible to reliably prevent a short circuit between terminals due to a migration phenomenon, whereby the relationship between the movement amount of the sliding member and the output voltage value can be normally reduced. Can be kept.

[Brief description of the drawings]

FIG. 1 is a front view showing elements of a throttle position sensor according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a terminal mounting portion of the element of FIG. 1;

FIG. 3 is a view B in FIG. 2 of a terminal mounting portion of the element of FIG. 1;
It is -B sectional drawing.

FIG. 4 is a front view showing a terminal mounting portion of an element of a throttle position sensor according to another embodiment of the present invention.

FIG. 5 is a front view showing elements of a conventional throttle position sensor.

FIG. 6 is a sectional view showing a terminal mounting portion of the element of FIG. 5;

FIG. 7 is a diagram showing a change in output voltage with respect to a brush movement amount.

[Explanation of symbols]

Reference Signs List 10 base (fixing member) 11 input terminal 12 first resistor 13 output terminal 14 second resistor 16 electrode film 17 solder (first protective film) 18 resistive film (second protective film) 19 PTFE resin film Or silicon resin coating (third
Protective film)

Claims (3)

(57) [Scope of request for utility model registration] 1. A position detecting device for detecting a position of an object to be detected by outputting a voltage corresponding to a conductive position of two resistors, wherein the electrode film is electrically connected to each resistor and contains silver. And a terminal attached to the electrode film by a first protective film, the terminal being electrically connected to the resistor through the electrode film, at least a part of the outer surface of the electrode film is covered with the terminal and the first protective film, In addition, the position detecting device is characterized in that the portion other than the terminal and the portion covered with the first protective film is covered with the second protective film. 2. The position detecting device according to claim 1, wherein the outer surfaces of the first and second protective films are covered with a third protective film having water repellency. 3. The position detecting device according to claim 1, wherein the second protective film is one of a resistive film and an insulating film.