JPS586109Y2 - inertia switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved electrode structure for an inertial switch, and particularly to an improved electrode structure for an inertial switch where electrode deterioration caused by electrochemical reactions is significant.

Inertial switches that detect deceleration (acceleration) applied to a device and generate an electrical signal are well known, and are widely used as accelerometers to detect excessive acceleration applied to devices, acceleration sensors for vehicle seat belt locks, or collision sensors. It is being

A typical inertial switch has an inertial body that moves within the housing at a constant deceleration (acceleration) rate in a housing that has two electrodes placed opposite each other, and the movement of the inertial body short-circuits both electrodes to generate an electrical signal. It consists of a configuration that outputs .

The above-mentioned conventional inertia switch has the disadvantage that if it is left in use for a long period of time, it tends to malfunction due to electrode deterioration.In particular, when it is used as a collision sensor for a vehicle, the electrode may be short-circuited due to a collision. This is a very rare occurrence, and is a very serious problem in that under normal operating conditions, the malfunction of the switch is not noticed, and only during an actual emergency operation, the malfunction is noticed and the desired sensing action cannot be achieved. was occurring.

Electrode malfunctions mainly occur because the electrodes are attacked by electrochemical reactions, and in particular, when placed in adverse conditions such as near humid roads such as in vehicles, rapid deterioration of the electrodes can occur. It has been known.

In normal cases, electrode deterioration is significant in the positive electrode connected to the positive electrode of the power supply, and rust on the positive electrode causes a voltage drop or poor contact at the electrode during switching operation.

The present invention has been devised in view of the above-mentioned conventional problems, and its purpose is to provide an improved inertia switch that is less likely to malfunction even when used for a long period of time.

In order to achieve the above object, the present invention provides an auxiliary electrode between the positive electrode and the negative electrode, partially connects the auxiliary electrode to the positive electrode, and also connects the auxiliary electrode to the positive electrode over the entire width. It is characterized by a structure in which it is shielded from the negative electrode.

The deterioration of the conventional electrode described above is caused by the potential difference applied to both electrodes, and the electrode part that deteriorates is also the part facing the positive electrode Q and the negative electrode. According to the present invention, as described above, the positive electrode By shielding the opposing portion from the negative electrode with the auxiliary electrode, it is possible to cause electrode deterioration to occur in the auxiliary electrode and protect the positive electrode from deterioration.

As described above, in the present invention, the auxiliary electrode deteriorates before the positive electrode, and the deterioration of the positive electrode can be delayed during this time.Furthermore, during this time, the deterioration of the auxiliary electrode is detected and an alarm is sent to warn of the danger of the inertial switch. Is possible.

For this reason, the auxiliary electrode in the present invention has a ring shape with a part of its circumference cut off, one end of the ring is electrically connected to the positive electrode, and the other end is connected to the alarm circuit. If there is a significant increase in conduction resistance due to deterioration in a part of the circuit, it is possible to detect this change in resistance and issue an alarm.

Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a preferred embodiment in which the inertia switch according to the present invention is used as a collision sensor for a vehicle.

The housing 10 is made of an insulating material such as plastic and is firmly fixed to the vehicle body.

An inertial body 14 made of a conductive material is movably housed in a cavity 12 in the housing 10, and an opening of the housing 10 is closed with a lid 16 made of an insulating material.

As shown in FIG. 2, a positive electrode 18, a negative electrode 20, and an auxiliary electrode 22 are formed and fixed on the inner surface of the lid 16.

The positive electrode 18 is connected to the battery and the negative electrode 2
0 is grounded to the vehicle body via a relay coil 34, which will be described later.

The inertial body 14 has a substantially disk shape, and has a shaft hole 14a formed in its shaft center.A spring 24 and a ball 26 are inserted into the shaft hole 14a, and the ball 26 is inserted into the spring 24.
It is urged to protrude from the lower surface of the inertial body 14 by the pressing force of.

The bottom of the housing 10 has a conical receiving part 1 at its center.
A ring-shaped receiving groove 10b having a triangular cross section is formed around the receiving part 0a and the receiving part 10a.

The inertial body 14 is normally located at the center of the empty chamber 12, and in this state, the ball 26 engages with the receiving portion 10a and is held in position.

In this holding state, the ring-shaped contact portion 14b formed at the periphery of the inertial body 140 is in contact with the auxiliary electrode 22 described above.

As is clear from the electrode structure in Figure 2, each electrode 18.2
Electrode plates 0 and 22 may be formed into thin plate shapes and may be fixed to the lid 16, or may be formed on the lid 16 by vapor deposition, electroless plating, or the like.

The positive electrode 18 and the negative electrode 20 have the same ring shape, and an auxiliary electrode 22 is formed between the two electrodes so as to shield them.

The auxiliary electrode 22 is provided with a cut portion A on a part of its circumference,
One end thereof is electrically connected to the positive side electrode 18 via a short circuit portion 22a, and the other end 22b is electrically connected to a lead portion 26 penetrating the lid 16, and the lead portion 28 is connected to an alarm circuit to be described later. There is.

The inertial switch according to the present invention has the above configuration, and its operation will be explained next.

The state shown in FIG.
4, the ball 26 of the housing 10Q is positioned and held in the receiving part 10a, so the inertial body 14 is located in the center of the cavity 12, and at this time, the contact part 14b is located at the center of the chamber 12 as shown by the dashed line in FIG. In addition, since it is in contact only with the auxiliary electrode 22, the positive side electrode 18 and the negative side electrode 20 are in an open state.

Therefore, in the state shown in FIG. 1, there is no need to output a collision detection signal to an external circuit.

When a vehicle collides or suddenly stops, a large deceleration (acceleration) is applied to the inertia switch, so the inertia body 14 moves in the direction of deceleration (acceleration) against the restraining force between the ball 26 and the receiving part 10a, and the ball 26 moves to a position where it engages with the ring-shaped receiving groove 10b and stops.

In this moving state, the contact part 14b moves to the position shown by the two-dot chain line in FIG. A collision detection signal can be output from the inertia switch to the outside.

FIG. 3 shows a circuit diagram of an inertial switch according to the present invention.

The positive electrode 18 is connected to a power supply terminal 32 via a relay contact 30, and the negative electrode 20 is grounded via a relay coil 34.

Relay contact 30 is inserted into the main power circuit of the vehicle, and contact 3
0 is further connected to a load 36, and when both electrodes 18 and 20 are closed due to detection of deceleration (acceleration), the relay coil 34 is energized, the contact 30 is opened, and the current supply to the load 36 is cut off. .

Therefore, in the event of a collision, it is possible to reliably prevent the occurrence of a fire due to the generation of electrical sparks in the vehicle load 36.

In the present invention, an auxiliary electrode 22 is connected to the positive electrode 18 via a short-circuit portion 22a, and an alarm circuit 38 is connected to the other end 22b of the auxiliary electrode 22.

Therefore, if a conduction failure or a significant increase in resistance occurs in the auxiliary electrode 22, it is possible to obtain an alarm such as a display or a chime from the alarm circuit 38.

The electrode arrangement according to the present invention is as shown in FIG.
Since the auxiliary electrode 22 is inserted between the negative electrode 20 and the positive electrode 18, the positive electrode 18 is shielded from the negative electrode 22.
It becomes possible to significantly delay deterioration of the positive electrode 18.

That is, in general, an electrochemical reaction occurs at the positive electrode between two electrodes that have a potential difference, resulting in an electrochemical reaction such as rust.
According to the electrode arrangement according to the present invention, the positive side electrode 18 and the auxiliary electrode 22 are at the same potential, and the auxiliary electrode 22 is at the same potential as the negative side electrode 22.
Since the electrodes are arranged opposite to each other, the electrochemical reaction occurs preferentially only at the auxiliary electrode.

Therefore, during the electrochemical reaction of the auxiliary electrode 22, the positive electrode 18
is protected by shielding from the negative electrode 20, and its characteristics will not deteriorate.

Therefore, in the inertial switch of the present invention, since the auxiliary electrode 22 takes charge of rust generation, when the inertial body 14 moves, the contact portion 14b is connected to the positive side electrode 18 and the negative side electrode 2, which do not deteriorate due to electrochemical reaction.
0, it is possible to reliably perform the detection operation in response to the deceleration (acceleration).

Although deterioration of the auxiliary electrode 22 cannot be avoided, according to the present invention, the ring-shaped auxiliary electrode 22 is shaped by cutting off a part of its circumference, and one end of the ring-shaped auxiliary electrode 22 is connected to the power source via the positive electrode 18.
Also, since the other end 22b is connected to an external alarm circuit,
If electrical custom-made deterioration such as an extreme increase in resistance occurs anywhere on the circumference of the auxiliary electrode 22, an alarm can be activated to notify the end of the life of the inertia switch, so that it can be detected before the positive electrode 18 deteriorates. It becomes possible to perform switch replacement and other maintenance inspections.

Normally, each electrode protrudes from the inner surface of the lid 16 by the thickness of the electrode, so when the inertial body 14 moves, the contact portion 14b collides with each electrode 18 and 20, which prevents the smooth movement of the inertial body 14. According to the present invention, since the contact portion 14b contacts the auxiliary electrode 22 and is supported by the auxiliary electrode 22 during movement as shown in FIG. 4, an extremely smooth moving action can be obtained. can.

The auxiliary electrode 22 may have the same thickness as the other electrodes 18, 20, or may be made slightly thinner so that the contact portion 1
When the positive side electrode 18 and the negative side electrode 20 are electrically connected by 4b, the auxiliary electrode 22 pushes up the contact part 14b and both electrodes 18.2
It is possible to prevent the conduction between the terminals 0 and 0 from being impaired.

As explained above, according to the present invention, deterioration of the positive and negative main electrodes used for the sensing action can be reliably prevented by having the auxiliary electrode share the deterioration of the electrode due to the electrochemical reaction occurring between the electrodes having a potential difference. In particular, it is possible to significantly improve weather resistance under adverse environments such as high humidity atmospheres, and it is possible to obtain a highly reliable inertial switch.

Furthermore, the auxiliary electrode can be used to warn of deterioration of the inertia switch, making it possible to perform maintenance and inspection of the inertia switch at an appropriate time.

[Brief explanation of the drawing]

Fig. 1 is a perspective view cut from the center showing a preferred embodiment of the inertia switch according to the present invention, Fig. 2 is a layout diagram showing the arrangement of each electrode provided on the inner surface of the lid in Fig. 1, and Fig. 3. 4 is a schematic circuit diagram showing a collision sensor and an inertia switch alarm circuit incorporating an inertia switch according to the present invention, and FIG. 4 is an explanatory diagram similar to FIG. be. 10...Housing, 14...Inertia body, 16...Lid, 18...Positive electrode, 2
0... Negative side electrode, 22... Auxiliary electrode.

Claims (1)

[Scope of utility model registration request] An inertial body is movably housed in a cavity of a housing having a positive electrode connected to a positive electrode of a power source and a negative electrode connected to a negative electrode of a power source, and the inertial body is moved by applying a deceleration (acceleration) velocity. In an inertia switch that detects an electrical signal by conducting and closing the positive and negative electrodes with an inertial body during movement, the positive and negative electrodes are formed in a ring shape arranged approximately concentrically, and there is a gap between the two electrodes. An auxiliary electrode is provided, and a part of the circumference of the auxiliary electrode is cut off, one end of which is electrically connected to the positive electrode, and the other end is connected to the negative electrode of the power source to warn of deterioration due to electrochemical reaction of the auxiliary electrode. An inertial switch connected to a circuit, characterized in that the auxiliary electrode shields the positive electrode from the negative electrode over substantially its entire width.