JPH0658781B2 - Collision speed detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collision speed detector mounted on a vehicle or the like, and more particularly to a collision speed detector that has a moving body that rotates and detects double integral acceleration.

A conventional structural example of this type of collision velocity detector is shown in FIG. The guide member 3 is supported and fixed by the insulating member 2 attached to the end of the casing 1 and the other end of the casing 1. A spiral groove is cut in the guide means 3, and a movable body 4 that can move back and forth along the spiral groove.
Is inserted in the guide means. The moving body 4 has a sliding member 5 through which the guide means 3 penetrates in the center, a plurality of balls 6 arranged between the sliding member 5 and the spiral groove of the guide means 3, and the sliding member 5. It comprises a metallic inertia member 7 for holding the moving member 5 from the outside. Also, this moving body 4
Is pressed in the direction of the casing 1 facing the insulating member 2 by the elastic body 8 mounted around the guide means 3. Further, the insulating member 2 has a pair of contact pieces 9A,
9B is fixed, and the contacts at the tips of the contact pieces 9A and 9B come into contact with the conductive member 10 attached to the side surface of the moving body 4. The other end of the contact piece 9A is connected to the positive electrode side of the power supply 11, and the other end of the contact piece 9B is connected to the load 12. The negative side of the power source 11 and the other end of the load 12 are grounded (for example, Japanese Patent Laid-Open No. 54-54).
44778).

In such a conventional collision speed detector having a multi-screw ball screw structure, the moving body 4 causes the contact piece 9 to move due to an impact at the time of collision.
It moves toward A and 9B, makes the contacts conductive, and causes a current to flow through the load 12, and the acceleration at that time is detected by this current. However, as shown in A of FIG.
Although the moving body 4 accurately follows a long-cycle impact of 2 to 20 msec or more, a positive / negative high impact is obtained in a short-cycle impact of about 3 to 8 msec as shown in FIG. 2B. Acceleration acts to increase the contact surface pressure between the point-contact ball 6 and the spiral groove of the guide means 3, resulting in an increase in the coefficient of friction, which deteriorates the screw efficiency and deteriorates the detection sensitivity. .

An object of the present invention is to eliminate the above-mentioned drawbacks and provide a collision velocity detector whose detection sensitivity does not change depending on the type of impact.

According to the present invention, in order to make the moving body follow the acceleration of a short period of 3 to 8 msec, the moving body is formed into surface contact capable of suppressing the contact surface pressure with the guide means, and the static friction coefficient and the dynamic friction coefficient are set. Focusing on the fact that it is necessary to reduce the difference between the two to eliminate the status slip, and to eliminate the loss time due to the alignment of the guide means with the ball or roller, it is necessary for the moving body to The above object is achieved by providing a fluorine resin nut having a lubricating property so that the nut slides along the spiral groove of the guide means.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings using the same reference numerals for the same parts as the conventional example.

FIG. 3 is an explanatory view showing the structure of an embodiment of the collision velocity detector of the present invention. Guide means 3 supported and fixed in the casing 1 by an insulating member 2 and an end portion of the casing 1.
Is provided. A moving body 4 is inserted into the guide means 3, and the moving body 4 is pressed by an elastic body 8 mounted on the outer peripheral portion of the guide means 3. Insulation member 2
A pair of contact pieces 9A, 9B are fixedly installed on the side of the movable body 4, and a conductive member 10 with which the contacts of the contact pieces 9A, 9B come into contact is attached to the side surface of the moving body 4. Furthermore, contact pieces 9A, 9B
The end of is connected to the power supply 11 and the load 12. Up to this point, the configuration is similar to that of the conventional example.

In the moving body 4 of this embodiment, as shown particularly in FIGS. 4 and 5, the sliding member 13 slidingly contacting the guide means 3 is the fifth member.
In the inner space 14 of the guiding means 3 shown in the drawing, there is a convex portion having a shape that fits, and this convex portion slides along the spiral groove of the guiding means 3 to rotate the moving body 4. To move. The moving body 4 is configured by integrally connecting the sliding member 13, the inertial member 7, and the conductive member 10. A liquid lubricant 15 is interposed between the spiral protrusion of the sliding member 13 and the spiral groove of the guide means 3. Further, the elastic body 8
Both ends of each are locked to the insulating member 2 and the inertia member 7 of the moving body 4, respectively, and the contact pieces 9a and 9B are normally electrically separated, so that the power source 11 and the load 12 are not electrically connected. There is.

When the vehicle collides, assuming that the direction of arrow G shown in FIG. 3 is positive, the moving body 4 which has received the impact energy due to the acceleration α (t) in FIG. 2 rotates and moves along the guide means 3. While the energy is converted to the elastic body 8 and a predetermined amount of energy is converted, the contact pieces 9A and 9B are short-circuited, so that the load 12 connected to the outside is supplied with power from the power supply 11.

Therefore, the sliding member 13 of the moving body 4 is formed of a composite resin containing a fluorinated resin having excellent self-lubricating property, and has a spiral convex portion formed on the sliding member 13. Therefore, it is in surface contact with the spiral groove of the guide means 3. Therefore, the shape and dimensions of the sliding member 13 are determined so as to ensure a contact surface pressure suitable for exerting lubricity without being deformed under various use conditions. In an actual collision, the period and acceleration are different depending on the objective, as shown by the waveforms A and B in Fig. 2. Therefore, the size and shape of the machine should be such that the contact surface pressure is optimum under the conditions where maximum acceleration occurs. Strength is secured.

On the other hand, under a use condition in which only a small acceleration is generated, the liquid lubricant (for example, silicon oil) 1 is used to compensate for the decrease in the contact surface pressure of the sliding member 13 and the decrease in the self-lubricating effect.
By supplying 5, the moving body 4 can be smoothly rotated along the guide means 3 under all use conditions. Further, the inertial member 7 constituting the moving body 4 is made of a metal material, and has a function as a reinforcement of the sliding member 13, a coupling means of the conductive member 10 and a means of increasing the rotational inertia moment.

In such a moving body 4 of the present embodiment, unlike the conventional case, no balls are interposed between the guide means and the sliding member.
There is no loss time such that the moving body 4 starts to move only when the load is evenly applied to the plurality of balls, and stable detection sensitivity can be obtained under the high frequency dump sign acceleration as shown in B of FIG.

FIG. 6 shows the acceleration α (t) of a one-sided antisine wave, and the velocity v ₀ corresponding to the area of this half sine wave is expressed by the following equation.

FIG. 7 shows the acceleration α (t) of the high frequency dump sine wave, and the velocity v ₀ ^* corresponding to the area of this wave is given by the following equation. However, in the figure, T ₁ ≈T ₂ .

The following table is a comparison of the accelerations shown in FIGS. 6 and 7 added to the conventional detector and the detector of the present embodiment.

As can be seen from the table, in the conventional detector, V ₀ ^* / V ₀
When the ratio is 1 or more, the sensitivity deterioration to the high frequency dump sine wave is clearly recognized. However, in the detector of the present embodiment, the ratio of V ₀ ^* / v ₀ is about 1, and it can be said that the sensitivity deterioration to the high frequency dump sine wave has not occurred.

According to the present embodiment, the spiral convex portion formed on the sliding member 13 of the moving body 4 is directly engaged with the spiral groove of the guide means 3 to form the surface contact capable of suppressing the contact surface pressure. In addition, the difference between the static friction coefficient and the dynamic friction coefficient is made small, and the loss time due to the alignment of the balls is eliminated, so that stable detection sensitivity can be obtained even under a short cycle high frequency dump sign acceleration, and the various shock wave cycles There is an effect that a constant detection sensitivity is always maintained regardless of the length of. Further, since no ball or the like is used for the moving body 4, it is possible to mold the sliding member 13 using a synthetic resin, which has an effect of reducing the cost. Furthermore, since there is no dense member such as a ball on the inner peripheral portion of the moving body 4 as in the prior art, and the dense inertia member 7 is arranged on the outer peripheral portion of the moving body 4, the moving movement of the moving body 4 is prevented. Since the inertial mass inside can be increased and the acceleration integration calculation distance can be shortened, there is an effect that the detector can be made compact. In addition, since the liquid lubricant 15 that compensates for insufficient self-lubrication is used under low acceleration, stable detection sensitivity can always be obtained.

8 and 9 are views showing another embodiment of the present invention. In the present embodiment, the detector is attached to the bumper portion of the vehicle and receives vibrations while the vehicle is running, so that the lubricant between the sliding member 13 of the moving body 4 and the guide means 3 is supplied without being connected. In order to do so, an annular oil reservoir recess 16 is formed on the sliding surface of the sliding member 13. The oil-impregnated member 1 containing the liquid lubricant 15 is contained in the recess 16 of the annular oil reservoir.
7. For example, felt or porous resin is loaded to prevent oil shortage. Other configurations are similar to those of the previous embodiment, and therefore illustration and description thereof are omitted.

This embodiment also has the same effect as the previous embodiment, but in particular, there is no oil shortage, and there is an effect of obtaining stable detection sensitivity even at low acceleration.

As described above, according to the collision velocity detector of the present invention, it is possible to provide a collision velocity detector whose detection sensitivity does not change depending on the type of impact.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the structure of a conventional collision speed detector, FIG. 2 is a diagram showing an example of acceleration at the time of a collision which acts on the collision speed detector, and FIG. 3 is a collision speed detector of the present invention. FIG. 4 is an explanatory view showing the structure of one embodiment, FIG. 4 is an enlarged sectional view of the moving body 4 shown in FIG. 3, FIG. 5 is a sectional view taken along line VV of FIG. 4, and FIG. FIG. 7 is a diagram showing a waveform, FIG. 7 is a diagram showing an acceleration waveform of a high frequency dump sine wave, FIG. 8 is a sectional view of a moving body which is an essential part of another embodiment of the present invention, and FIG. 8th
FIG. 9 is a sectional view taken along line IX-IX in the figure. 1 ... Casing, 3 ... Guide means, 4 ... Moving body, 9
A, 9B ... Contact piece, 13 ... Sliding member.

Claims (5)

[Claims] 1. A casing, a movable body movable with respect to the casing, a spiral guide means for rotating the movable body to advance and retreat, and an elastic body for absorbing the kinetic energy of the movable body. A collision speed detector comprising a switch that closes when the moving body moves a predetermined distance against the elastic body, wherein the moving body is made of fluorinated resin or the like that slides along the guide means. A collision speed detector comprising: a sliding member made of a material containing a low friction resin; and an inertial member fixed to the outer periphery of the sliding member and made of a material having a density higher than that of the sliding member. . 2. A spiral groove is provided on the outer peripheral surface of the guide means, and a spiral convex portion that engages with and slides in the spiral groove is formed on the sliding member. 2. A collision velocity detector according to claim 1. 3. The collision speed detector according to claim 1, wherein the moving body engages with the guide means via a liquid lubricant. 4. The collision velocity detector according to claim 1, wherein a concave portion for oil sump different from the groove corresponding to the guide means is formed on the sliding surface of the sliding member. . 5. An annular recess is provided on the sliding surface of the sliding member,
The collision velocity detector according to claim 1, wherein an oil-containing member containing lubricating oil is inserted into the recess.