JPH11291951A - Control device for car body rigidity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a car body rigidity control device which can absorb shocks properly irrespective of the style of car collision. SOLUTION: A car body rigidity control device comprises a left and a right frame rigidity adjusting means 4 which are installed on a left 2 and a right side frame 3, respectively, extending fore and aft of the car and adjust the rigidity of the side frames, and a control means 8 which controls the operation of the rigidity adjusting means according to the collision style judged on the basis of the output of a collision sensing means 5 such as acceleration sensor. Thereby each side frame is adjusted into a rigidity suitable for the applicable collision style, and proper shock absorbing performance is exerted in any style, whether total collision or partial.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body rigidity control device for controlling vehicle body rigidity in a vehicle having a collision impact absorbing structure so as to obtain appropriate rigidity according to the type of collision.

[0002]

2. Description of the Related Art Since the rigidity of a vehicle body has a great influence on the handling and the like, a high-strength steel plate is used for a frame member constituting the vehicle body, the plate thickness is increased, or a reinforcing material is provided at an appropriate position. However, at the same time, from the viewpoint of enhancing occupant protection in the event of a vehicle collision, a vehicle body structure capable of appropriately absorbing collision energy is desired. Since the impact absorption at the time of this collision is mainly performed by plastic deformation of the left and right side frames extending in the front-rear direction at the front of the vehicle body, by appropriately setting the rigidity of the side frames, The resulting deceleration can be kept low to reduce the impact on the occupant.

[0003]

However, in a collision mode in which the front of the vehicle body totally collides, such as a frontal barrier collision (hereinafter, referred to as a full collision), external collision forces are distributed to the left and right side frames. On the other hand, in a collision mode in which the front surface of the vehicle body partially collides, such as an offset collision (hereinafter, referred to as a partial collision), external collision forces concentrate on one side frame. Therefore, for example, if the right and left side frames are set to rigidity suitable for a partial collision, the rigidity becomes excessive with respect to shock absorption in a full collision, causing a large deceleration, and conversely, suitable for a full collision If the rigidity is set to a low level, the impact on the vehicle compartment will increase due to insufficient rigidity during partial collisions and insufficient shock absorption. There are difficult aspects.

An object of the present invention is to solve such a problem of the prior art and to provide a vehicle body stiffness control device for performing appropriate shock absorption regardless of the type of collision. It was devised.

[0005]

In order to achieve such an object, in the present invention, a vehicle body rigidity control device is mounted on left and right side frames 2 and 3 extending in the front-rear direction of the vehicle 1, respectively. Left and right frame rigidity adjusting means 4 for adjusting the rigidity of the left and right side frames, and control means 8 for controlling the operation of the left and right frame rigidity adjusting means in accordance with the collision mode determined based on the output of the collision detecting means 5. And According to this, the left and right side frames are adjusted to the rigidity suitable for the collision mode by the left and right frame rigidity adjusting means, and the appropriate impact absorption can be performed in any of the full collision mode and the partial collision mode.

In particular, the frame rigidity adjusting means includes a solid element actuator composed of a piezoelectric element or a magnetostrictive element that generates a load in a direction of restraining or promoting plastic deformation of the side frame, or a rigidity of the side frame. It is preferable that the reinforcing member is displaceable between a position to be increased and a position that does not affect the rigidity of the side frame. In addition, a similar effect can be obtained with a reinforcing member connected to the side frame via an explosion bolt destroyed in response to an operation signal from the control means.

The collision detecting means may include an acceleration sensor for detecting an acceleration generated in the longitudinal direction of the vehicle body at the time of the collision, a distortion sensor for detecting a distortion generated at the side frame or the like at the time of the collision, or a deformation of the vehicle body at the time of the collision. It is preferable to use a displacement sensor for detecting a displacement of a measurement point determined at an appropriate position of the vehicle body, such as a side frame or a bumper mounting member, accompanying the above. Of these, the acceleration sensor uses a piezoelectric element that outputs a voltage signal due to strain, a semiconductor that changes the resistance value due to strain, or a glass fiber that changes the transmission characteristics due to strain. There are those that sense. Examples of the strain sensor include those using the strain detection materials listed in the above acceleration sensor. In addition, a configuration in which a solid-state actuator including a piezoelectric element and a magnetostrictive element is used can also be used. Examples of the displacement sensor include a sensor using a variable resistor, a laser displacement meter, and a limit switch having a simple gap structure.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a vehicle body rigidity control device according to the present invention. This vehicle body rigidity control device includes a plurality of piezoelectric actuators 4 as frame rigidity adjusting means mounted on each of left and right side frames 2 and 3 extending in the front-rear direction at the front of the vehicle 1, and the left and right side frames 2. 3 has a pair of left and right acceleration sensors 5 as collision detection means mounted on each of the three, and a controller 8 as control means arranged on the center frame 7. The side frames 2 and 3 are formed to have relatively low rigidity in accordance with a full collision.

As shown in FIG. 2, the piezoelectric actuator 4 is provided at the inner side of the neutral portions of the two bent portions 9 and 10 in the crank-shaped portions of the side frames 2 and 3, respectively. 3 are provided in series in a state of being sandwiched between the mounting members 11 and 12 at the ends and the mounting members 13 at the intermediate portion, which are tightly fixed to the outer wall surface of the third mounting member. The pair of piezoelectric actuators 4 are arranged in a state of being bent in a U-shape along the axis of the side frames 2 and 3 with the intermediate mounting member 13 interposed therebetween.

As shown in detail in FIG. 3, the piezoelectric actuator 4 has a rectangular flat plate-shaped piezoelectric element panel 15 made of PZT or the like that generates a load in accordance with a voltage applied from the controller 8, and front and back of the piezoelectric element panel 15. A pair of copper electrodes 16 provided on both sides,
And a coating 18 made of epoxy resin integrated by thermocompression so as to cover the copper electrode 16. Note that a conductive sheet containing Ni is preferably provided between the piezoelectric element panel 15 and the copper electrode 16, and a polyimide film is provided on both front and back surfaces of the cover 18.

As shown in FIG. 4, the controller 8
A pair of A / D converters 21 for A / D-converting the output signals of the left and right acceleration sensors 5 and a collision type are determined based on the output signals of the A / D converters 21. CP that outputs an operation signal of the piezoelectric actuator 4 of FIG.
U22 and a switching circuit 24 for applying the voltage of the power supply 23 to the piezoelectric actuator 4 by the switching operation of the transistor in accordance with the output signal of the CPU 22.

In the vehicle body rigidity control device configured as described above, the output signal of the left and right acceleration sensors 5 is always A
/ Through D converter 21 is input to the CPU 22, as shown in FIG. 5, the acceleration G _L · G _R indicated by the output signal from the acceleration sensor 5, the pre-stored reference to the storage unit (not shown) of the controller 8 Is compared with the value G ₀ (steps 1 to
3). Here, both the left and right acceleration G _L · G _R are both the reference value G
_If it is ₀ or more, it is determined that a full collision has occurred (step 4). In this case, the operation ends without operating the piezoelectric actuator 4, and the left and right sides are set to have relatively low rigidity in advance in accordance with the full collision. The frames 2 and 3 undergo the expected plastic deformation and absorb the impact.

Both the left and right accelerations G _L and G _R are reference values G _0.
If it is smaller than the above, it is determined that there is no collision (step 5), and the process ends without operating the piezoelectric actuator 4 as described above.

On the other hand, when the left acceleration _GL is equal to or more than the reference value G ₀ and the right acceleration G _R falls below the reference value G ₀ , it is determined that the left partial collision has occurred (step 6). A power supply voltage is applied to the provided piezoelectric actuator 4 (Step 7). On the other hand, the left acceleration G _L falls below the reference value G ₀ and the right acceleration G _R is the reference value G ₀ or more, it is determined that the right part collision (Step 8), provided on the right side frame 3 A power supply voltage is applied to the piezoelectric actuator 4 (step 9).

When a power supply voltage is applied to the piezoelectric actuator 4 provided on either of the left and right side frames 2 and 3 in this manner, the piezoelectric actuator 4 exerts an extension force as shown by an arrow in FIG. Occurs. This is because, when an external impact force in the axial direction indicated by the arrow A is input to the side frames 2 and 3, the compressive deformation generated in the portion where the piezoelectric actuator 4 is provided is restrained, and
Acts to increase the rigidity of Therefore, the predetermined side frames 2 and 3 are in a relatively high rigidity state suitable for a partial collision, and appropriate shock absorption is performed.

In this case, the piezoelectric actuator 4 is operated to increase the rigidity of the side frames 2 and 3. However, the piezoelectric actuator 4 is operated to decrease the rigidity of the side frames 2 and 3. 4 is also possible. In this case, the side frames 2 and 3 having relatively high rigidity suitable for a partial collision are formed in advance, and only when it is determined that a full collision has occurred (step 4 in FIG. 5), the piezoelectric members of both the side frames 2 and 3 are formed. The actuators 4 are simultaneously operated to control the rigidity of the left and right side frames 2 and 3 so as to decrease to a rigidity suitable for a full collision.

FIG. 6 shows an example in which a magnetostrictive actuator 31 is provided on a linear portion of the side frames 2 and 3 as a frame rigidity adjusting means.

The magnetostrictive actuator 31 includes a magnetostrictive element panel 32 that generates a load according to the strength of the magnetic field, an exciting coil 33 that generates a magnetic field applied to the magnetostrictive element panel 32,
A yoke 34 is provided as magnetic attraction means for guiding the magnetic field generated by the exciting coil 33 to the magnetostrictive panel 32. The magnetostrictive element panel 32 is formed by forming a known giant magnetostrictive material such as a Tb-Dy-Fe alloy into a rectangular flat plate by a known forming method such as casting, cutting, sintering, or vapor deposition.
The yoke 34 is formed of a soft magnetic material such as electromagnetic steel, and has a pair of magnetic pole portions 35.3 joined to a pair of mutually opposing side edges of the rectangular magnetostrictive element panel 32, respectively.
6, a pair of arms 37 and 38 extending in the same direction from the longitudinal center of both magnetic poles 35 and 36, and a pair of arms 37 and
An excitation core 33 is provided between the cores 39 in a state of being installed between the cores 39. In addition, side frame 2
It is preferable to form a magnetic seal layer made of a non-magnetic material such as Mo or Al on the surfaces of the magnetic pole portions 35 and 36 which are in contact with (3).

Here, the magnetostrictive actuator 3 is inserted into a rectangular mounting hole 40 formed in the peripheral wall of the side frames 2 and 3.
1 is mounted, and a side frame 2 is
The operating current from the controller 8 is supplied via the lead wire 41 inserted into the inside 3.

A strain sensor 42 composed of a piezoelectric element or the like is provided on the peripheral walls of the side frames 2 and 3 as a collision detecting means, and a distortion signal from the distortion sensor 42 is always input to the controller 8, and Based on the above, the controller 8 determines the collision mode in the same manner as described above.

When a control voltage is applied from the controller 8 to the excitation coil 33 based on the result of the determination of the collision mode, a load is generated on the magnetostrictive element panel 32 in a direction to suppress the distortion of the peripheral walls of the side frames 2 and 3. This load is applied to the side frame 2 via the magnetic pole portions 35 and 36 of the yoke 34.
3 is transmitted. The generated load of the magnetostrictive element panel 32 acts to suppress the deformation of the linear portions of the side frames 2 and 3 so as to increase the buckling stress, thereby obtaining required rigidity.

In the embodiment shown in FIG. 2 and the embodiment shown in FIG. 6, the method of mounting the piezoelectric and magnetostrictive actuators 4 and 31 to the side frames 2 and 3 and the arrangement position are different. Although different from each other, these piezoelectric and magnetostrictive actuators 4 and 31 have the same function as each other, and can be in any suitable combination as well as in the opposite manner.

FIG. 7 shows a reinforcing plate 51 inside the hollow left and right side frames 2 and 3 as a frame rigidity adjusting means.
The example which provided is shown. Here, one end of the reinforcing plate 51 arranged in a substantially horizontal direction is rigidly connected to the inner surface of the inclined portion of the upper wall 52 of the side frames 2 and 3 in a cantilever manner. In the vicinity of the other end of the reinforcing plate 51, a projection 54 projects from the inner surface of the lower wall 53 of the side frames 2.3. A piezoelectric actuator 55 having substantially the same configuration as the piezoelectric actuator 4 shown in FIG. 3 is closely arranged on both upper and lower surfaces of the reinforcing plate 51. The left and right side frames 2 and 3 themselves are formed to have relatively low rigidity in accordance with a full collision.

When the external force in the direction indicated by arrow A is input to the side frames 2 and 3 when the reinforcing plate 51 is at the initial position in the substantially horizontal direction, the tip of the reinforcing plate 51 and the projection 54 are caught. The upper and lower walls 52 of the side frames 2 and 3
Deformation in the direction in which 53 approaches is restricted, and the rigidity of the side frames 2 and 3 is increased.

On the other hand, when an operating voltage is applied to the upper and lower piezoelectric actuators 55, a contraction force is generated in the upper piezoelectric actuator 55, and an extension force is generated in the lower piezoelectric actuator 55, The reinforcing plate 51 bends as indicated by the imaginary line in the figure. When an external collision force is input to the side frames 2 and 3 in this state, the tip of the reinforcing plate 51 and the projection 5
4, the side frames 2 and 3 are plastically deformed in a relatively low rigidity state in which the reinforcing plate 51 does not function effectively.

[0027] In this case, unlike the control method of the embodiment shown in FIG. 5 above, both the acceleration G _L · G _R of the left and right is determined to entirely collide with both the reference value G ₀ or more (Fig. 5 Only in step 4), the piezoelectric actuators 55 provided on the reinforcing plates 51 of the left and right side frames 2 and 3 are simultaneously operated. As a result, the left and right side frames 2 and 3 absorb the impact in a relatively low rigidity state, and the deceleration generated in the vehicle compartment can be suppressed to a low level.

In other cases, the piezoelectric actuator 55 is not operated, and the reinforcing plate 51 remains at the initial position. By this, if it is a partial collision on either side,
The reinforcing plate 51 functions and the predetermined side frames 2 and 3 are plastically deformed in a relatively high rigidity state, so that appropriate impact absorption is performed.

Contrary to the above, a configuration is possible in which the reinforcing plate does not function at the initial position, and is displaced to a position where the reinforcing plate functions by the operation of the piezoelectric actuator 55. in this case,
What is necessary is just to perform control similarly to the control method shown in FIG. Also,
The piezoelectric actuator 55 can operate not only to displace the reinforcing plate 51 but also to increase the rigidity of the reinforcing plate 51 itself. Further, it is possible to use a magnetostrictive actuator similar to the magnetostrictive actuator 31 shown in FIG. 6 in place of the piezoelectric actuator 55 for displacing the reinforcing plate 51.

FIGS. 8 to 10 show modifications of the embodiment shown in FIG. In FIG. 8, a reinforcing plate 61 is provided at the bent portion of the side frames 2 and 3 in substantially the same manner as described above, and the reinforcing plate 61 has one end that can tilt with respect to the upper wall 52 of the side frames 2 and 3. Is fixed, and is tilted upward by a motor 62 that operates in response to an operation signal of the controller 8, and as shown by an imaginary line in FIG.
The reinforcing plate 61 is displaced to a position where it does not function. Instead of the motor 62, the reinforcing plate 61 may be tilted and driven by a spring. In this case, the configuration may be such that the locking means of the spring is released in response to the operation signal of the controller 8.

In FIG. 9, the reinforcing plate 63 is tiltably fixed to the side frames 2 and 3 similarly to the embodiment shown in FIG. 8, but the reinforcing plate 63 is provided on the reinforcing plate 63. The tilt drive is performed by magnetic attraction generated between the coil 64 and the fixed iron core 65 provided on the side frames 2 and 3. 10, in place of the protrusion 54 in the embodiment shown in FIG. 7, a step 66 is formed on the lower wall 53 to be engaged with the tip of the reinforcing plate 51.

In the embodiment shown in FIG. 1, the collision type is determined based on the difference in the magnitude of the left and right accelerations detected by the left and right acceleration sensors 5; It is also possible to determine the form of collision with one acceleration sensor arranged on the frame 7. FIG. 11 shows the change over time of the acceleration generated on the vehicle body in each of the frontal collision modes and the offset by the actual vehicle. As is apparent from this figure, the acceleration fluctuation waveforms are significantly different between the offset and frontal collision modes. That is, in the offset collision, the acceleration rises later than in the head-on collision, and the peak occurrence timing is shifted back and forth in both the offset and head-on collision modes. By setting a criterion by paying attention to this difference, it is possible to determine the collision mode. In particular, early determination is possible by determining the type of collision based on a peak occurring around 8 ms during a frontal collision. Note that the acceleration fluctuation waveform shown in FIG. 11 differs depending on the vehicle body structure, and the actual determination criteria are appropriately set according to the vehicle body to which the present apparatus is applied. When a single acceleration sensor is used to determine the type of collision, the acceleration sensor can also be used as an airbag device.

Further, in the above-described embodiment, the acceleration sensor or the strain sensor is used as the collision detecting means. However, the piezoelectric element itself forming the solid-state actuator has a function of outputting a voltage corresponding to the amount of strain. Further, since the magnetostrictive element can output a voltage signal corresponding to the distortion via the exciting coil, as shown in FIG. 12, a configuration in which the solid-state actuator 71 composed of a piezoelectric element or a magnetostrictive element is also used as a collision detecting means is also available. It is possible. Here, the state of the solid-state actuator 71 is monitored by the monitor circuit 72, and when a distortion equal to or more than a predetermined value is detected, the CPU 22 determines the collision mode. The other configuration is the same as that shown in FIG. 4 described above. An operation signal of the solid state actuator 71 is output from the CPU 22 based on the result of the determination of the collision mode, and the required solid state actuator is output via the switching circuit 24. The voltage of the power supply 23 is applied to 71.

[0034]

As described above, according to the present invention, the left and right side frames are adjusted to the rigidity suitable for the collision mode by the left and right frame rigidity adjusting means. Since the impact can be absorbed, a great effect can be achieved in enhancing the occupant protection ability in the event of a collision.

[Brief description of the drawings]

FIG. 1 is a top view showing a state in which a vehicle body rigidity control device according to the present invention is applied to a vehicle body frame.

FIG. 2 is a side view showing a main part of a side frame provided with the piezoelectric actuator shown in FIG. 1;

FIG. 3 is a perspective view showing the piezoelectric actuator shown in FIG. 1;

FIG. 4 is a block diagram of the vehicle body rigidity control device shown in FIG. 1;

FIG. 5 is a flowchart of a control method of the vehicle body rigidity control device shown in FIG. 1;

FIG. 6 is a perspective view showing a main part of a vehicle body rigidity control device using a magnetostrictive actuator.

FIG. 7 is a longitudinal sectional view showing a main part of a vehicle body rigidity control device using a reinforcing plate.

FIG. 8 is a longitudinal sectional view showing a modification of the vehicle body rigidity control device shown in FIG. 7;

FIG. 9 is a longitudinal sectional view showing a modification of the vehicle body rigidity control device shown in FIG. 7;

FIG. 10 is a longitudinal sectional view showing a modification of the vehicle body rigidity control device shown in FIG. 7;

FIG. 11 is a graph showing a temporal change in acceleration generated in a vehicle body during a collision.

FIG. 12 is a block diagram showing an example in which a solid-state element actuator is also used as collision detection means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle 2.3 Side frame 4 Piezoelectric actuator 5 Acceleration sensor 7 Center frame 8 Controller 9.10 Bend section 11.12.13 Mounting member 15 Piezoelectric element panel 16 Copper electrode 18 Coating body 21 A / D converter 22 CPU 23 Power supply 24 Switching Circuit 31 Magnetostrictive Actuator 32 Magnetostrictive Element Panel 33 Excitation Coil 34 Yoke 35/36 Magnetic Pole 37/38 Arm 39 Iron Core 40 Mounting Hole 41 Lead Wire 42 Strain Sensor 51 Reinforcement Plate 52 Upper Wall 53 Lower Wall 54 Protrusion 55 Piezoelectric Actuator 61/63 Reinforcement plate 62 Motor 64 Coil 65 Fixed iron core 66 Step 71 Solid-state actuator 72 Monitor circuit

Claims (3)

[Claims] The determination is made based on outputs of a left and right frame rigidity adjusting means mounted on left and right side frames extending in the front-rear direction of the vehicle to adjust the rigidity of the left and right side frames, respectively, and an output of the collision detecting means. Control means for controlling the operation of the right and left frame rigidity adjusting means according to the type of collision. 2. The vehicle body rigidity control according to claim 1, wherein the frame rigidity adjusting means is a solid-state actuator that generates a load in a direction in which deformation of the side frame is restrained or in a direction that promotes the deformation. apparatus. 3. The frame rigidity adjusting means according to claim 1, wherein said frame rigidity adjusting means is a reinforcing member which can be displaced between a position where the rigidity of said side frame is increased and a position which does not affect the rigidity of said side frame. A vehicle body rigidity control device as described in the above.