JPH04228342A - Automobile collision sensor structure - Google Patents

Abstract

PURPOSE:To provide automobile collision sensor structure enabling the continuous signal output from the initial time of accelerating action without generating the action delay of an air bag system by preventing the rebound of a conductive member. CONSTITUTION:A cushion 20 is provided on the wall surface 12A of a moving space 12 on the side where terminals 14, 15 are buried, and a steel ball 13, a conductive member, moves in the moving space 12 by a magnet 16 against suction force to come in contact with the contacts 14A, 15A of the terminals 14, 15, and further comes in contact with the cushion 20 to prevent repulsion on the wall surface 12A.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collision sensor structure used in an automobile airbag system, and more particularly to a mounting structure for improving the detection accuracy of a collision sensor.

0002

2. Description of the Related Art An air bag system is one of the systems intended to improve the safety of occupants in the event of a car collision. (Refer to Japanese Unexamined Patent Publication No. 63-255153, etc.) The airbag system deflates and stores a bag-shaped airbag in front of the occupant, and applies gas pressure to this airbag in the event of a collision. The device is inflated in a space that prevents occupants from colliding with the steering wheel, dashboard, etc. to ensure safety. Detection of a collision in such an airbag system is performed by a collision detection sensor as shown in FIGS. 23 to 25. In the collision detection sensor 10 shown in FIG. 23, a ball (mass) 10A of a predetermined mass as a conductive member formed of a magnetic material is fitted into a space 10B that can be moved by a predetermined stroke, and is attached to one end side of the space 10B. A magnet 10C is disposed, and a pair of electrical contacts 10D in a non-conducting state are provided at the other end to protrude into the space 10B. The sphere 10A moves into space 10 due to the magnetic attraction force of the magnet 10C.
It is attracted and biased toward one end side of the ball B (the side where the magnet 10C is arranged), and is attached to the vehicle body with the side opposite to the biasing direction of the ball 10A (that is, the contact 10D side: indicated by the arrow in the figure) forward in the traveling direction. When a predetermined or more negative acceleration (impact) is applied in the forward direction, such as in the event of a collision, the ball 10A is moved by the magnet 10 due to its inertia.
Contact point 1 resists the magnetic attraction force of C as shown by the dashed line in the figure.
The ball 10A moves to the 0D side and makes the contact 10D conductive.

FIGS. 24 and 25 show other methods,
The illustrated collision detection sensor 30 has a cylindrical housing 31
A rotor 33 with a weight 32 of a predetermined mass fixed at a predetermined position near the outer periphery is rotatably supported within the rotor 33 by a shaft 34, and a contact piece 35 as a conductive member is connected to the rotor 33 from a symmetrical position across the center of rotation of the housing. 31, and a pair of electrical contacts 36 and 37 in a non-conducting state are arranged on the end inner wall 31A of the housing 31 corresponding to the contact piece 35. There is. The rotor 33 has its contact pieces 35 and electrical contacts 36
, 37 are spaced apart from each other by a predetermined distance.
When the rotor 33 rotates against the urging force of the spring 38, the contact pieces 35 come into contact with the electrical contacts 36 and 37, and the electric The contact points 36 and 37 are electrically connected by the contact piece 35, and the weight 32 is mounted on the vehicle body with the tangential direction of the arcuate locus of movement of the weight 32 due to the rotation of the rotor 33 being substantially forward in the traveling direction. When a predetermined or more negative acceleration (impact) is applied in the forward direction, such as during a collision, the rotor 33 rotates against the urging force of the spring 38 due to the inertial force of the weight 32, and the contact piece 35 connects to the electrical contact 36, 37 to establish conduction. That is, in this configuration, the weight 32, the rotor 33, and the contact piece 35 constitute a conductive member.

0004

[Problems with the Prior Art] However, in the collision detection sensor structure as described above, when a negative acceleration (impact) of a predetermined value or more is applied in the forward direction, the conductive member moves once and conducts between the contacts. There is a problem in that the signal is not continuously output due to the repulsion and separation from the contact point, which may result in a delay in the operation of the airbag system. That is, in the configuration shown in FIG. 23, after the ball 10A moves toward the contact 10D and makes the contact 10D conductive, the contact 10A goes through the state shown by the two-dot chain line in the figure.
0D or the wall surface where the contact 10D is installed (
There is a possibility that it will repel) and separate from the contact 10D.
In the configurations 25 to 25, there is a possibility that the contact piece 35 contacts the electrical contacts 36, 37 to establish conduction, and then is bounced back by the electrical contacts 36, 37, causing the contact piece to separate from the electrical contacts. In an airbag system, in order to prevent malfunction and ensure stable operation, the condition for activation is that the detection signal from the collision detection sensor continues for a predetermined period of time (for example, 3 msec). When the ball 35 repulses, the output signals from the collision detection sensors 10 and 20 become intermittent as shown in FIG.
The airbag system will not operate until A continues to be in contact with the contact 10D for a predetermined period of time (contact 10D is conductive) (or until the contact piece 35 continues to be in contact with the electrical contacts 36 and 37), and the airbag system will not operate. The start is slightly delayed and it is not possible to respond quickly to the initial stage of the acceleration action.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention has been made to enable a continuous output of a signal from the initial stage of acceleration by preventing the conductive member from bouncing back, thereby preventing a delay in the activation of an airbag system for an automobile. The purpose of the present invention is to provide a collision detection sensor structure for use in automobiles.

[0006]

[Structure of the Invention] Therefore, in the collision detection sensor structure for an automobile according to the present invention, a conductive member having a predetermined mass moves inertia to simultaneously contact a pair of non-conducting contacts, thereby causing a connection between the contacts. A collision detection sensor configured to detect a collision by establishing a conductive state is provided with a repulsion movement regulating means for preventing the conductive member from repulsively moving in a direction away from the contact after contacting the contact. It is something. As a result, the repulsion of the conductive member is prevented by the repulsion movement regulating portion, and conduction between the contacts is maintained, so that a signal can be continuously output from the initial stage of the acceleration action. In addition, the repulsion movement regulating means may be constructed by lowering the coefficient of repulsion of the contact point or a wall surface portion including the contact point, or configured such that the repulsion direction of the conductive member is different from the moving direction of the conductive member, The contact point and the conductive member are configured to engage with each other.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a longitudinal sectional view of an embodiment of a collision detection sensor structure for an automobile according to the present invention. In the illustrated collision detection sensor 10, a steel ball 13 as a conductive member is inserted in a cylindrical space 12 of a predetermined length formed in a case 11, and the steel ball 13 moves inside the moving space 12 along its longitudinal direction. It is possible to move along the direction. The surface of the steel ball 13 is plated with gold to a predetermined thickness so that electrical resistance is low and a good conductive state can be obtained. A pair of terminals 14 are provided in the wall surface 12A on one side in the longitudinal direction of the moving space 12.
, 15 are buried symmetrically across the longitudinal axis of the moving space 12, and the tips of both terminals 14, 15 protrude into the moving space 12 to constitute opposing contacts 14A, 15A.
4A and 15A are separated by a predetermined interval and are in a non-contact state (that is, a non-conducting state). The opposing contacts 14A, 15A
has a predetermined distance from the wall surface 12A of the moving space 12 on the side where the terminals 14 and 15 are provided, and the terminals 14 and 15 are elastically deformed due to their own elasticity until they come into contact with the wall surface 12A with a relatively weak force. It is possible. Terminals 14, 15
A magnet 16 is externally mounted on the outside of the case end on the opposite side to the side where the magnet 16 is provided, and the magnet 16 attracts the steel ball 13 with its magnetic attraction force, and the magnet 16 is placed on the wall surface of the moving space 12 on the side where the magnet 16 is arranged. 12B to maintain a state of contact with the wall surface 12B.

With the above configuration, when an acceleration of a predetermined value or more is applied to the collision sensor 10 toward the side where the magnet 16 is attached, the steel ball 13 resists the magnetic attraction force of the magnet 16 and moves inside the moving space 12 to the terminal. The steel ball 13 moves to the 14 and 15 sides and contacts both contacts 14A and 15A at the same time, so that the steel ball 13 establishes conduction between both contacts 14A and 15A. In other words, a switch corresponding to the acceleration acting on the terminals 14 and 15 and the steel ball 13 is configured, and by installing the switch in the vehicle with the terminals 14 and 15 side facing forward in the direction of travel (indicated by the arrow in the figure), When the vehicle collides with the front while the vehicle is running, and a negative acceleration of a predetermined value or more is applied to the front in the direction of travel (plus acceleration to the rear), the steel ball 13 will move toward the direction of travel (towards the terminals 14 and 15) due to inertia. Move both contacts 14A,
15A, the electric circuit configured via both terminals 14 and 15 becomes conductive (ON) and a signal is output, and a collision is detected by this signal output. Here, in the center of the wall surface 12A of the moving space 12 on the side where the terminals 14 and 15 are buried, that is, in a portion corresponding to the opposing portion of the contacts 14A and 15A, a cushion 20 is provided as a repulsion movement regulating means. . The cushion 20 is made of a low resilience material such as urethane rubber that has a shock absorbing effect, for example.
Contact 14A with a diameter smaller than the distance between the ends of contacts 14A and 15A
, 15A so as not to protrude toward the steel ball 13 arrangement side.

[0009] As described above, the terminal 1 of the moving space 12
A cushion 20 is placed on the wall surface 12A on the side where 4 and 15 are buried.
With this provision, the steel ball 13 moves in the space toward the terminals 14 and 15 due to the action of acceleration, contacts the contacts 14A and 15A, and establishes conduction between the terminals 14 and 15. Thereafter, the steel ball 13 hits the cushion 20. Since the terminals 14 and 15 are in contact with each other and kinetic energy is absorbed, the terminals 14 and 15 continue to be in a conductive state without rebounding and continue to output signals. In other words, even if the steel ball 13 conducts between the terminals 14 and 15 and outputs a signal due to the action of acceleration, the next moment the steel ball 13 connects to the wall surface 12A.
This does not cause the problem that conduction (signal output) between the terminals 14 and 15 does not continue for a predetermined period of time due to the rebound. The material of the cushion 20 is not limited to the above embodiments, and may be changed as appropriate, for example, by using a foam material such as sponge, as long as it has a shock absorbing effect. In addition to the above configuration, the moving space 1
By setting the gap between the steel ball 2 and the steel ball 13 as small as possible within a range that does not impede the movement of the steel ball 13, the air in the moving space 12 acts as a damper, and the steel ball 1 once moved is
3 can be made difficult to return to.

Next, another embodiment of the present invention will be explained. Note that the same reference numerals are given to the same functional parts as in the above embodiment, and the explanation thereof will be omitted. 2 and 3 show examples of cushions 21 having different shapes from those of the above-mentioned examples. This is a cylindrical structure made of a foam material such as a sponge, and has 1 steel ball.
3. In the event of a collision, the impact absorption effect becomes greater by deforming into a barrel shape as shown in FIG. 4 and 5 show a plurality of small diameter and flexible hair-like protrusions 22 protruding or implanted on the same circumference instead of the cushions 20 and 21 in the above embodiment to restrict repulsive movement. It was used as a means. The tip 22A of each trichome is cut obliquely from the outside to the inside, as shown in FIG.
This cut makes the tip 22A more flexible so that it can receive the steel ball 13 in a soft manner. In FIG. 6, the contacts 14A, 15A of the terminals 14, 15 are made of a material that is easily deformed plastically and formed into a shape that is easily deformed. can prevent backlash.

FIG. 7 shows an embodiment of a different technical idea of the repulsive movement restricting means. This is formed by forming an inclined wall surface 12C in which the wall surface on the side where the terminals 14 and 15 are buried is tilted at a predetermined angle from a state perpendicular to the axial direction of the moving space 12 (that is, the moving direction of the steel ball 13). . According to this configuration, the rebound direction of the steel ball 13 that collides with the inclined wall surface 12C is the direction of movement of the steel ball 13 leading to the collision (the axial direction of the moving space 12) and the perpendicular line of the inclined wall surface 12C at the collision position. However, this direction is the direction of the peripheral wall of the movement space 12 and cannot be moved in that direction, and as a result, the rebound of the steel ball 13 is restricted by the peripheral wall, and the contact points 14A, 15A is maintained. Figure 8
9 to 9 show other embodiments of the same technical idea, in which the terminal 1
A cylindrical protrusion 23 or a hemispherical protrusion 24 is provided on the wall surface 12A on the side where the steel balls 13 are buried, at a position offset by a predetermined amount from the position (center) where the steel ball 13 abuts. With this configuration as well, the repulsion direction of the steel ball 13 is different from the axial direction of the moving space 12, and the same effect can be obtained. In FIG. 10, the thicknesses of both terminals 14' and 15' are made different, and the elastic return forces of each terminal are set to be unbalanced. As a result, the rebound direction of the steel ball 13 is changed to the moving space 12 due to the difference in elastic force between both terminals 14' and 15'.
The axial direction of the steel ball 13 is different from the axial direction of the contact point 14A, and the rebound of the steel ball 13 is regulated by the surrounding wall surface as in the above-mentioned embodiment.
, 15A is maintained. Figure 11 shows
Contrary to the embodiment shown in FIG. 7, the axial direction of the movement space 12 in which the steel balls 13 move is tilted forward and downward relative to the wall surface 12A on the side where the terminals 14 and 15 are buried. According to this, the movement of the steel ball 13 is regulated by the upper wall surface of the movement space 12, and the movement of the steel ball 13 is regulated by the upper wall surface of the moving space 12, and the movement of the steel ball 13 is regulated by the upper wall surface of the moving space 12, and
The rebound of the steel ball 13 is regulated by the lower peripheral wall surface, and the contact points 14A, 15A
contact is maintained. 12 and 13 show that the lower peripheral wall surface of the movement space 12 in which the steel ball 13 moves is tilted forward and downward, and according to this, the vehicle body on which the collision detection sensor 10 is mounted is When the frame deforms forward and downward during a collision, the lower peripheral wall surface stands up more vertically, preventing the reaction movement of the steel balls 13 and maintaining contact with the contacts 14A, 15A.

FIG. 14 shows that the internal structure of the collision detection sensor 10 itself is the same as the one without the repulsion movement regulating means in the above embodiment, but the movement space 12 in which the steel ball 13 moves is
The repulsion movement restricting means is mounted on the vehicle body with the axial direction of the terminals 14, 15 buried side ends facing downward at a predetermined angle from the horizontal. Collision detection sensor 10
has mounting arms 17A and 17 on its front end and lower side.
As shown in FIG. 15, the lower mounting bolt is the lower mounting bolt of the two upper and lower mounting bolts 41A and 41B of the towing tie-down hook 41 that is attached to the front end of the front frame 40 of the vehicle body. 41B together with the lower arm 17B, and by fastening the front arm 17A alone to the front frame 40, the movable space 12 is created with the terminals 14, 15 buried side ends on the lower side as described above. It is installed at a predetermined angle from the horizontal. In the figure, 42 is a bumper portion, and 43 is a suspension cross member. According to this configuration, the movement of the steel ball 13 in the horizontal direction, which is the acting direction of acceleration, is regulated by the upper wall surface of the movement space 12.
The steel ball 13 moves forward along the axial direction of the moving space 12 by rolling on the upper peripheral wall surface, and due to the rotation and the action of gravity, the direction of rebound of the steel ball 13 is different from the axial direction of the moving space 12 (downward). ) Therefore, the rebound of the steel ball 13 is regulated by the surrounding wall surface, and the contact points 14A, 15A
contact is maintained. In addition, in this embodiment, the front frame 40 necessarily has rigidity due to its function.
Collision detection sensor 10 is attached to the tie-down hook 41 attachment part.
Since it is installed, the crushable space 40A is shown in Figure 16.
As shown in FIG. 2, even if the device deforms and absorbs the impact during a collision, detection errors due to changes in the mounting position or angle or damage can be prevented. The location where the collision detection sensor 10 is attached is not limited to the location where the tie-down hook 41 is attached, but may be attached to any part of the vehicle body frame that deforms in the longitudinal direction of the vehicle without moving vertically in the event of a collision. It is changeable.

FIG. 17 shows the technical concept of shifting the direction of repulsion of the conductive member from the direction of its movement, which was explained in the above embodiment, by rotating the rotor 33 to which the weight 32 is fixed.
3 is a conceptual explanatory diagram applied to a collision detection sensor having a configuration in which a contact piece 35 fixed to a rotor 33 conducts electrical contacts 36 and 37;
A weight 32 is movably attached to A. According to this configuration, in the setting state shown by the solid line in the figure, the weight 32 is located below the elongated hole 33A in the direction of gravity (that is, near the center of rotation), and from this state, the weight 32 moves in the direction of vehicle movement shown by the arrow in the figure. When negative acceleration is applied, weight 3
As shown by the imaginary line in the figure, the rotor 2 moves in the outer circumferential direction within the elongated hole 33A due to its inertia, and also rotates the rotor 33 to move in the direction of acceleration (position indicated by X in the figure). At this time, the contact piece 35 fixed to the rotor 33 conducts the electrical contacts 36 and 37, and then the repulsive force between the contact piece 35 and the electric contacts 36 and 37 acts to rotate the rotor 33 in the reverse direction.
In this state, the weight 32 is located at the outermost side of the elongated hole 33A (near the outer periphery of the rotor 33), so the rotor 33
The moment of inertia of the rotor 33 is larger than the initial setting position (the weight 32 is located closest to the innermost circumference of the rotor 33), and requires greater rotational energy, and the repulsive force causes the weight 32 to move along the longitudinal direction of the elongated hole 33A. Rotor 33
As a result, conduction between the electrical contacts 36 and 37 by the contact piece 35 can be maintained.

FIG. 18 shows an embodiment of a further different technical idea of the repulsion movement restricting means. In this configuration, a pair of terminals 14 and 15 are buried in the end wall surface 12A of the moving space 12, and the distance between the contacts 14A and 15A at the tip thereof is set to be slightly narrower than the diameter of the steel ball 13, and the terminal The shapes of the terminals 14 and 15 are formed so that the steel ball 13 can be held between the terminals 14 and 15 and the end wall surface 12A as shown by the imaginary lines in the figure. As a result, the moving steel ball 13 moves to the terminal 14.
, 15 to bring them into contact, the terminals 14A, 15A pass between the terminals 14A, 15A and are held between the terminals 14, 15 and the end wall surface 12A, completely preventing repulsive movement. It can be prevented. FIGS. 19 and 20 illustrate the above technical concept in which a rotor 33 to which a weight 32 is fixed rotates, and a contact piece 35 fixed to the rotor 33 makes an electrical contact 36,
This is an embodiment applied to a collision detection sensor having a configuration in which the weight 37 is electrically conductive, and this configuration has a backlash prevention member 39 formed of an elastic material such as rubber on the inner periphery of the housing 31 so that the movement area of the weight 32 is slightly different from the movement range of the weight 32. As shown in FIG. 20, which is a conceptual configuration diagram, the contact piece 35 connects to the electrical contacts 36 and 37 at a position where the weight 32 has climbed over the return prevention member 39.
It is designed to conduct by contacting with. As a result, the weight 32 that has once climbed over the reverse prevention member 39
is prevented from returning due to its repulsive force. In FIG. 21, engaging portions 36A and 37A are provided in which the surface portions of the electrical contacts 36 and 37 that the contact pieces 35 come into contact with are uneven as shown in FIG. 22, which is an enlarged cross-sectional view, and the tips of the contact pieces 35 engage It is configured to engage with the mating portions 36A and 37A to prevent repulsion.

[0015]

As described above, according to the collision detection sensor structure for an automobile according to the present invention, it is possible to prevent the conductive member from rebounding at the contact point or the wall surface on which the contact point is provided by the repulsion movement prevention means. As a result, continuous contact with the contact point of the conductive member is possible, and a signal can be continuously outputted from the beginning of the acceleration action, without causing a delay in the operation of the airbag system.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a collision sensor to which an embodiment of the automobile collision sensor structure according to the present invention is applied.

FIG. 2 is a sectional view of another embodiment.

FIG. 3 is a partial view showing the operating state of FIG. 2;

FIG. 4 is a cross-sectional view of a different embodiment.

FIG. 5 is a partial perspective view of FIG. 4;

FIG. 6 is a cross-sectional view of a different embodiment.

FIG. 7 is a cross-sectional view of a different embodiment.

FIG. 8 is a cross-sectional view of a different embodiment.

FIG. 9 is a cross-sectional view of a different embodiment.

FIG. 10 is a cross-sectional view of a different embodiment.

FIG. 11 is a cross-sectional view of a different embodiment.

FIG. 12 is a cross-sectional view of a different embodiment.

FIG. 13 is a cross-sectional view of a different embodiment.

FIG. 14 is a cross-sectional view of a different embodiment.

FIG. 15 is a diagram showing the state of attachment to the frame of FIG. 14;

FIG. 16 is a diagram showing the state at the time of the collision in FIG. 14;

FIG. 17 is a conceptual explanatory diagram of an embodiment of a collision detection sensor in which a rotor to which a weight and a contact piece are fixed rotates to conduct electrical contacts.

FIG. 18 is a cross-sectional view of a different embodiment.

FIG. 19 is a cross-sectional view of an embodiment of a collision sensor in which a rotor to which a weight and a contact piece are fixed rotates to conduct electrical contacts.

FIG. 20 is a conceptual explanatory diagram of the embodiment of FIG. 19;

FIG. 21 is a conceptual explanatory diagram of a different embodiment.

FIG. 22 is a partially enlarged sectional view of the embodiment of FIG. 22;

FIG. 23 is a cross-sectional view of a conventional automobile collision sensor.

FIG. 24 is a cross-sectional view of a conventional automobile collision detection sensor of a different type from that shown in FIG. 23;

FIG. 25 is a conceptual explanatory diagram of FIG. 24;

FIG. 26 is a diagram showing a signal output state in a conventional example.

[Explanation of symbols]

10...Collision detection sensor 12...Movement space (movement path) 12A...Wall surface (wall surface with contacts) 12C...Slanted wall surface (repulsion movement regulating means) 13...Steel ball (conducting member) 14, 15...Terminals 14', 15' ...Terminal (repulsion movement regulating means) 14A, 1
5A... Contact 20... Cushion (repulsion movement regulating means) 21... Cushion (repulsion movement regulating means) 22... Ciliary projection (repulsion movement regulating means) 23... Protrusion (repulsion movement regulating means) 30... Collision detection sensor 32... Weight ( 33... Rotor (conducting member) 33A... Long hole (repulsion movement regulating means) 35... Contact piece (conducting member)

Claims (7)

[Claims] [Claim 1] A collision configured to detect a collision by simultaneously contacting a pair of non-conducting contacts by inertial movement of a conductive member having a predetermined mass and bringing the contacts into a conductive state. The sensing sensor is configured to include a repulsive movement regulating means for preventing the conductive member from repulsively moving in a direction away from the contact after contacting the contact;
An automotive collision detection sensor structure featuring: 2. The collision detection sensor structure for an automobile according to claim 1, wherein the repulsion movement restricting means lowers the repulsion coefficient of the contact point or a wall surface portion provided with the contact point. 3. A collision detection sensor for an automobile according to claim 1, wherein the repulsion movement regulating means sets a repulsion direction of the conductive member in a direction different from a moving direction of the conductive member. structure. 4. The collision detection sensor structure for an automobile according to claim 1, wherein the repulsion movement restricting means is configured such that the contact point and the conductive member engage with each other. 5. The conductive member is formed of a magnetic material, the conductive member is movably disposed within the moving passage, and a magnet disposed at one end of the moving passage moves the conductive member into the moving passage. At the same time, it is held by suction at one end of the
The collision detection sensor has the pair of contacts disposed at the other end of the movement path, and the repulsion movement regulating means tilts the movement path from horizontal with the collision detection sensor positioned at the contact arrangement side end downward. 4. The collision detection sensor structure for an automobile according to claim 3, wherein the structure is configured by being fixed to a vehicle body in a fixed state. 6. The collision detection sensor structure for an automobile according to claim 5, wherein the collision detection sensor is fixed to a towing hook member mounting portion at the tip of the front frame. 7. The collision detection sensor according to claim 5, wherein the collision detection sensor is fixed to a body frame that deforms in the longitudinal direction of the vehicle without moving in the vertical direction of the vehicle during a collision. Sensing sensor structure.