JPH0686078U - Acceleration sensor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an acceleration sensor having a function capable of performing failure diagnosis without applying shock. [Structure] The rotating mass 15 to which the movable contact 16 is fixed is constantly pressed by the plate spring 14 toward the stopper 31 side, and the fixed contact 13 is connected to the plate spring fixing base 18 side.
The acceleration sensor provided with the driving means for driving the rotating mass 15 by an electromagnetic force.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an acceleration sensor, and more particularly, to a mechanical acceleration sensor used for detecting impact acceleration of an airbag system in a vehicle, for example.

[0002]

[Prior art]

 FIG. 7 is a perspective view schematically showing a conventional acceleration sensor. Reference numeral 12 in the drawing denotes a base, and a plate spring fixing base 18 is fixed on the base 12. A support portion 18a to which the plate spring 14 is fixed and a support portion 18b to which the stopper 17 is screwed are formed on the plate spring fixing base 18 perpendicularly to the bottom plate 18c of the plate spring fixing base 18, respectively. A fixed contact point 13 is provided in the. The movable contact 16 that comes into contact with the fixed contact 13 is fixed to the side surface of the cylindrical rotary mass 15, and the rotary mass 15 to which the movable contact 16 is fixed has the bottom plate 18c on the support portion 18b side. One end of the biasing plate spring 14 is wound.

The rotating mass 15 normally contacts the stopper 17 and is pressed toward the stopper 17 by the spring force of the plate spring 14. The peripheral portion of the movable contact 16 in the plate spring 14 is cut off so that the contact between the fixed contact 13 and the movable contact 16 is not obstructed. In a normal state, a predetermined space is provided between the movable contact 16 and the fixed contact 13, and when the acceleration acts, the movable contact 16 is rotated by the rotation of the rotating mass 15 toward the supporting portion 18a. Will be in contact with. This predetermined interval is adjusted by adjusting the screwing amount of the screw-shaped stopper 17 to the support portion 18b.

The acceleration sensor thus configured is fixed to the chassis 11, and a cap (not shown) is covered and welded on the chassis 11, and is mounted in, for example, an ECU for an airbag. .

Next, the operation of the acceleration sensor configured as described above will be described. In a normal state, as shown in FIG. 7A, the rotating mass 15 is urged toward the stopper 17 by the spring force of the plate spring 14 and is in contact with the stopper 17, and the fixed contact 13 and the movable contact 16 are in contact with each other. Away from. When an acceleration of a certain value or more is applied in the direction of the support portion 18a from this state, the rotating mass 15 rotates against the plate spring 14 as shown in FIG. 7B, and the movable contact 16 and the fixed contact 13 come into contact with each other. However, electrical communication will be achieved.

FIG. 8 is a sectional view schematically showing a conventional example different from the above conventional example. In the figure, 22 indicates a movable portion, and this movable portion 22 is a magnetic body formed in a cylindrical shape. The movable part 22 is fixed to one end of the coil spring 21, the other end of the coil spring 21 is fixed to the case 23, and the movable part 22 is slidably supported by the case 23. The coil spring 21 generates a spring force in the case 23, and the spring force presses the movable portion 22 in the direction A in the figure. Lead wires 20a and 20b are inserted into the coil spring 21, and these lead wires 20a and 20b are drawn out of the case 23. These lead wires 20a and 20b are set to have the same poles as the movable portion 22, and a repulsive force acts between the lead wires 20a and 20b. An open detection resistor 24 is connected to the lead wires 20a and 20b.

The operation of the acceleration sensor configured as above will be described. In the normal state, the movable portion 22 presses the case 23 in the A direction by the spring force of the coil spring 21, as shown in FIG. When an acceleration of a certain value or more is applied in the direction opposite to the A direction from this state, the acceleration sensor operates. That is, when the movable portion 22 slides in the B direction against the coil spring 21 and passes through the tips of the lead wires 20a and 20b, the repulsive force against the movable portion 22 causes the lead wire 20a and the lead wire 20b to separate. Contact is made and electrical continuity is achieved.

[0008]

[Problems to be solved by the device]

 The above-mentioned malfunction of the acceleration sensor may be caused by, for example, a fixed contact 13 and a movable contact 16 due to foreign matter mixed in, a contact failure between the lead wire 20a and the lead wire 20b, or a fixed spring 13 due to a failure of the plate spring 14. There is a contact failure or a contact failure between the lead wire 20a and the lead wire 20b due to a failure of the coil spring 21. Therefore, it is necessary to check the operation of the acceleration sensor.

However, in the above-mentioned acceleration sensor, since it is hermetically sealed by the cap and the chassis 11 or the case 23, after being hermetically sealed, after being mounted in the vehicle, a shock (constant at a constant level) is generated. There is a problem that the acceleration sensor is not actuated unless an acceleration equal to or more than a value) is applied, and that the malfunction of the acceleration sensor is not detected until after the collision of the vehicle.

The present invention has been devised in view of such problems, and an object thereof is to provide an acceleration sensor having a function capable of performing a failure diagnosis without applying an impact.

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, in the acceleration sensor according to the present invention, the rotating mass with the movable contact fixed is constantly pressed against the stopper side by the plate spring, and the fixed contact is disposed on the fixed base side of the plate spring. The acceleration sensor is characterized by including a driving unit that drives the rotating mass by an electromagnetic force.

Further, the acceleration sensor according to the present invention is configured such that the movable portion made of a magnetic material is constantly pressed by the spring in one direction, and the contact is closed by the movement of the movable portion in the opposite direction to the one direction. The acceleration sensor is characterized by including drive means for driving the movable portion by an electromagnetic force.

[0013]

In the acceleration sensor having the above structure, the rotating mass having the movable contact fixed thereto is constantly pressed by the plate spring toward the stopper side, and the fixed contact is disposed on the fixed base side of the plate spring. Since the driving means for driving the rotating mass by electromagnetic force is provided, the driving of the rotating mass is easy by the driving means without applying impact (acceleration above a certain value) at the time of collision to the rotating mass. Will be done. Therefore, the contact state between the movable contact and the fixed contact can be easily checked in the factory, and the failure of the acceleration sensor can be detected in advance. Further, even after the acceleration sensor is incorporated in the vehicle, the failure diagnosis can be performed, and the reliability of the acceleration sensor is improved.

Further, in the acceleration sensor having the above structure, the movable part made of a magnetic material is constantly pressed by the spring in one direction, and the contact is closed by the movement of the movable part in the opposite direction to the one direction. Since the acceleration sensor is provided with a drive means for driving the movable part by an electromagnetic force, the movable part is driven by the drive without applying a shock (acceleration of a certain value or more) at the time of collision to the movable part. It will be easily carried out by means. Therefore, the contact state of the contacts is easily checked in the factory, and the failure of the acceleration sensor is detected in advance. Further, it becomes possible to perform a failure diagnosis even after the vehicle is equipped with the acceleration sensor, and the reliability of the acceleration sensor is improved.

[0015]

【Example】

 An embodiment of an acceleration sensor according to the present invention will be described below with reference to the drawings. It should be noted that components having the same functions as those of the conventional example are designated by the same reference numerals. 1 is a plan view schematically showing a first embodiment of an acceleration sensor according to the present invention. Reference numeral 35 in the figure denotes a drive shaft, and a permanent magnet 34 is fixed to one end of the drive shaft 35. The drive shaft 35 passes through the cap 30, the support portion 18b, and the coil spring 32 having one end fixed to the support portion 18b, and is in contact with the rotating mass 15. The other end of the coil spring 32 is fixed to the end of the drive shaft 35 that is in contact with the rotating mass 15, and a stopper 31 is provided at a predetermined position of the drive shaft 35. It is urged in the direction of arrow B and is positioned with respect to the support portion 18b by the stopper 31. Other configurations are similar to those of the acceleration sensor shown in FIG.

The check function of the acceleration sensor thus configured will be described. First, the electromagnet 33 is installed at a predetermined distance from the permanent magnet 34, a current is passed through the electromagnet 33, and the end of the electromagnet 33 on the permanent magnet 34 side is set to have the same pole as the permanent magnet 34. At this time, a repulsive force in the direction of arrow A is applied to the permanent magnet 34, and the drive shaft 35 moves in the direction of arrow A against the spring force of the coil spring 32. With the movement of the drive shaft 35, the rotating mass 15 rotates in the direction of arrow A against the spring force of the plate spring 14. The contact state between the movable contact 16 and the fixed contact 13 due to this rotation is checked via a monitor lamp (not shown) or the like. As a result, the acceleration sensor can be easily checked without applying impact (acceleration above a certain value) at the time of collision.

If this check is performed in the factory, it is possible to detect a failure of the acceleration sensor before the vehicle is mounted. Furthermore, by disposing the electromagnet 33 in the vicinity of the acceleration sensor even after being installed in the vehicle, failure diagnosis can be performed at any time.

FIG. 2 is a diagram schematically showing a second embodiment of the acceleration sensor according to the present invention. (A) is a plan view and (b) is a side view. In the figure, reference numeral 36 denotes a drive shaft that serves as a central axis of the rotary mass 15. Permanent magnets 34 are fixed to both ends of the drive shaft 36, and the drive shaft 36 has a long hole 30a formed on a side surface on the long side of the cap 30, Also, the rotary mass 15 is inserted and slidably supported in the long hole 30a. Other configurations are similar to those of the acceleration sensor shown in FIG.

The check function of the acceleration sensor thus configured will be described. First, the electromagnet 33 is installed at a predetermined distance from the permanent magnet 34, a current is passed through the electromagnet 33, and the end of the electromagnet 33 on the permanent magnet 34 side is set to have the same pole as the permanent magnet 34. At this time, a repulsive force in the direction of arrow A is applied to the permanent magnet 34, and the drive shaft 36 is moved in the direction of arrow A. The rotational mass 15 rotates in the direction of arrow A against the spring force of the plate spring 14 in conjunction with the movement of the drive shaft 36. The contact state between the movable contact 16 and the fixed contact 13 due to this rotation is checked via a monitor lamp (not shown) or the like. As a result, the acceleration sensor can be easily checked without applying a shock (acceleration above a certain value) at the time of collision. Other effects similar to those of the first embodiment can be obtained.

FIG. 3 is a plan view schematically showing Example 3 of the acceleration sensor according to the present invention. In the figure, 34 indicates a permanent magnet, and the permanent magnet 34 is fixed to both ends of the rotating mass 15. The cap 30 is formed by using a resin material, and electromagnets 33 are arranged on both outer sides of the long sides of the cap 30. Other configurations are similar to those of the acceleration sensor shown in FIG.

The check function of the acceleration sensor thus configured will be described. First, a current is passed through the electromagnet 33 to set the end of the electromagnet 33 near the permanent magnet 34 to the same pole as the permanent magnet 34. At this time, the permanent magnet 34 receives a repulsive force from the end of the electromagnet 33 set to the same pole as the permanent magnet 34, and moves in the direction of arrow A. The rotary mass 15 rotates in the direction of arrow A against the spring force of the plate spring 14 in conjunction with the movement of the permanent magnet 34. The contact state between the movable contact 16 and the fixed contact 13 due to this rotation is checked via a monitor lamp (not shown) or the like. As a result, the acceleration sensor can be easily checked without applying impact (acceleration above a certain value) at the time of collision. Other effects similar to those of the first embodiment can be obtained.

Further, when the acceleration sensor shown in FIGS. 2 and 3 is equipped with the electromagnet 33 and is used for detecting the impact acceleration of an airbag system in a vehicle, for example, the current flowing to the electromagnet 33 is in the opposite direction to that at the time of checking. The permanent magnet 34 is attracted to the electromagnet 33 and the rotation of the rotating mass 15 can be prevented even when an acceleration of a preset value or more is applied, so that electrical continuity can be prevented. This makes it possible to prevent malfunction of the airbag even if another sensor fails.

FIG. 4 is a sectional view schematically showing Example 4 of the acceleration sensor according to the present invention. Reference numeral 22 in the figure denotes a movable portion, and the movable portion 22 is pressed in the direction of arrow A by the spring force of the coil spring 21. A recess 51a is formed in the center of the right side of the case 51 that abuts the movable portion 22, and an electromagnet 38 is disposed in the recess 51a. The other structure is the same as that of the acceleration sensor shown in FIG.

The check function of the acceleration sensor thus configured will be described. First, the electromagnet 38 is energized so that the end portion side facing the movable portion 22 has the same pole as the movable portion 22. At this time, a repulsive force in the direction of arrow B is applied to the movable portion 22 from the electromagnet 38, and the movable portion 22 slides in the direction of arrow B against the spring force of the coil spring 21, and the lead wire 20a and the lead wire 20a. Reach the tip position of line 20b. The state of contact between the lead wire 20a and the lead wire 20b due to the sliding of the movable portion 22 is checked via a monitor lamp (not shown) or the like. As a result, the acceleration sensor can be easily checked in the factory or in the vehicle without applying impact (acceleration above a certain value) at the time of collision.

FIG. 5 is a schematic diagram showing the configuration of the ignition circuit of the airbag system. The acceleration sensor shown in FIG. 4 is equipped as a sensor 54, for example. One end of the acceleration sensor 54 is connected to the battery 53, the other end of the acceleration sensor 54 is connected to one end of the squib 52, and the other end of the squib 52 is connected in parallel to one end of the sensors 55 and 56. The other ends of 56 and 56 are grounded. The acceleration sensor 54 is arranged in the ECU and is set so as to detect even a light impact applied to a running vehicle that does not affect the driver, for example, an impact applied during traveling on a stepped portion, and to be turned on. . On the other hand, the sensor 55 and the sensor 56 are arranged in front of the vehicle, and are set so as to detect an impact at the time of a collision and turn on.

Further, in the ignition circuit configured as described above, the following effects can be obtained by energizing the electromagnet 38 in the direction opposite to that at the time of checking. When the sensor 55 and / or the sensor 56 in FIG. 5 are short-circuited, the electromagnet 38 is energized in the direction opposite to that at the time of checking, so that the electromagnet 38 can generate a force for attracting the movable portion 22. As a result, the acceleration sensor 54 can be prevented from being turned on even when the acceleration sensor 54 receives an acceleration equal to or higher than a normal set value, and malfunction of the airbag can be prevented.

Furthermore, since the set value for impact detection can be changed by changing the spring strength of the coil spring 21 in the acceleration sensor 54, the acceleration sensor 54 can be used as the sensor 55 and / or the sensor 56.

FIG. 6 is a sectional view schematically showing Example 5 of the acceleration sensor according to the present invention. Reference numeral 22 in the figure denotes a movable portion, and the movable portion 22 is pressed in the direction of arrow A by the spring force of the coil spring 21. A recess 51a is formed in the center of the right side of the case 51 that comes into contact with the movable portion 22, and a coil 37 is disposed in the recess 51a. A movable shaft 39 is inserted through the coil 37, and the movable shaft 39 is fixed to the movable portion 22. Other configurations are similar to those of the acceleration sensor shown in FIG.

1 A check function of the acceleration sensor configured as above will be described. First, the coil 37 is energized so that the end side facing the movable portion 22 has the same pole as the movable portion 22. At this time, since the drive shaft 39 is inserted through the coil 37, the magnetomotive force is increased and a repulsive force in the arrow B direction is generated with respect to the movable portion 22. Due to this repulsive force, the movable portion 22 slides in the direction of arrow B against the spring force of the coil spring 21, and reaches the tip end positions of the lead wires 20a and 20b. The state of contact between the lead wire 20a and the lead wire 20b due to the sliding of the movable portion 22 is checked via a monitor lamp (not shown) or the like. As a result, the acceleration sensor can be easily checked without applying a shock (acceleration above a certain value) at the time of collision. Other effects similar to those of the fourth embodiment can be obtained.

[0030]

[Effect of device]

 As described in detail above, in the acceleration sensor according to the present invention, the rotating mass having the movable contact fixed is constantly pressed by the plate spring toward the stopper side, and the fixed contact is disposed on the fixed base side of the plate spring. Since the acceleration sensor is equipped with a driving unit that drives the rotating mass by an electromagnetic force, the rotating mass can be driven without applying an impact (acceleration of a certain value or more) at the time of collision to the rotating mass. This can be easily done by the driving means. Therefore, the contact state between the movable contact and the fixed contact can be easily checked in the factory, and the failure of the acceleration sensor can be detected in advance. Further, since the failure diagnosis can be performed even after the acceleration sensor is incorporated in the vehicle, the reliability of the acceleration sensor can be improved.

In addition, in the acceleration sensor configured such that the movable portion made of a magnetic material is constantly pressed by the spring in one direction, and the contact is closed by the movement of the movable portion in the opposite direction to the one direction, In the case where a drive means for driving the movable section by electromagnetic force is provided, it is possible to easily drive the movable section by the drive means without applying a shock (acceleration of a certain value or more) at the time of collision to the movable section. It can be carried out. Therefore, it is possible to easily check the contact status of the contacts at the factory, and to detect the failure of the acceleration sensor in advance. Further, when the vehicle is equipped with the acceleration sensor, a failure diagnosis can be performed at any time, so that the reliability of the acceleration sensor can be improved.

[Brief description of drawings]

FIG. 1 is a plan view schematically showing Example 1 of an acceleration sensor according to the present invention.

FIG. 2 is a plan view schematically showing a second embodiment of an acceleration sensor according to the present invention, (a) is a plan view and (b) is a side view.

FIG. 3 is a plan view schematically showing Example 3 of the acceleration sensor according to the present invention.

FIG. 4 is a sectional view schematically showing Example 4 of the acceleration sensor according to the present invention.

FIG. 5 is a schematic diagram showing a configuration of an ignition circuit of the airbag system.

FIG. 6 is a sectional view schematically showing Example 5 of an acceleration sensor according to the present invention.

FIG. 7 is a perspective view schematically showing a conventional acceleration sensor, (a) showing a non-operating state and (b) showing a operating state.

FIG. 8 is a cross-sectional view schematically showing another conventional acceleration sensor.

[Explanation of symbols]

 13 Fixed Contact 14 Plate Spring 15 Rotating Mass 16 Moving Contact 18 Plate Spring Fixed Base 31 Stopper

Claims (2)

[Scope of utility model registration request] 1. An acceleration sensor in which a rotary mass having a movable contact fixed thereto is constantly pressed by a plate spring toward a stopper side, and a fixed contact is provided on a fixed base side of the plate spring, wherein the rotary mass is generated by an electromagnetic force. An acceleration sensor comprising driving means for driving. 2. An acceleration sensor configured such that a movable part made of a magnetic material is constantly pressed by a spring in one direction, and a contact is closed by moving the movable part in a direction opposite to the one direction. An acceleration sensor, characterized in that the acceleration sensor is provided with a driving means for driving the electromagnetic wave.