KR20180055172A - Sensor for vehicle - Google Patents

Abstract

The present invention relates to a detection sensor for a vehicle, wherein a film having a thickness is formed to maintain effective performance of a sensor cell in the front of the sensor cell. The detection sensor comprises: a hollow housing in which a through hole communicating with the outside is formed in one end, and an accommodation groove is formed in the other end; a sensor cell arranged in the through hole for one end thereof to be exposed from the through hole; an elastic rubber cap formed to be hollow, coupled to an outer circumferential surface of the sensor cell protruding from the through hole, and inserted into a mounting hole; a PCB electrically connected to the sensor cell to be arranged in the accommodation groove; and a potting member filled in the accommodation groove to seal one end of the rubber cap and the PCB from the outside.

Description

[0001] SENSOR FOR VEHICLE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a sensor for a vehicle, and more particularly, to a sensor for a vehicle in which a coating film having a thickness capable of maintaining an efficient performance of a sensor cell is formed on a sensor cell.

In general, a bumper, such as an ultrasonic sensor, is mounted on the front and rear of the vehicle, or both the front and rear bumper to detect objects and obstacles when the vehicle is stationary.

In particular, a sensor, which is generated via a piezoelectric element, performs sensing using ultrasonic waves. When a high frequency electric energy is applied to a piezoelectric element, The same number of rapid vibrations occur.

At this time, when the frequency applied to the piezoelectric element is 20 kHz or more, the piezoelectric element generates ultrasonic waves having a specific frequency band that can not be heard by humans due to vibration.

That is, the ultrasonic pulse signal is transmitted intermittently, and objects and obstacles are detected by receiving reflected waves from nearby obstacles.

1, the conventional conventional vehicle sensing sensor includes a housing 1 having a receiving groove formed therein, a sensor cell 2 for sensing an object, and a housing 1 and a sensor cell 2 A rubber cap 3 disposed between the sensor housing 2 and the sensor cell 2 for mounting the vehicle sensor to the bumper 6 of the vehicle, a PCB 4 electrically connected to the sensor cell 2, And a potting member 5 which is filled and blocks the PCB 4 from the outside.

The rubber cap 3 accommodates the sensor cell 2 to prevent interference with other parts so that the sensor cell 2 freely vibrates when the sensor cell 2 vibrates and the vibration of the sensor cell 2 It acts as a vibration proof to prevent it from being transmitted to other parts.

The rubber cap 3 is fixed to the housing 1 in a state in which the sensor cell 2 is accommodated.

Here, the rubber cap 3 to which the sensor cell 2 is coupled is mounted on the bumper 6 of the vehicle. Since the sensor cell 2 vibrates with its natural frequency and vibration characteristics, It react sensitively.

Therefore, the rubber cap 3 is made of a thin and low-hardness material to protect the sensor cell 2 from external interference and to maintain vibration characteristics.

On the other hand, when the sensor is mounted on the bumper 6 of the vehicle, the front surface of the sensor cell 2 is exposed to the outside of the bumper.

Therefore, the front surface of the sensor cell 2 should be coated with a color matching with the color of the bumper.

When the front surface of the sensor cell 2 is coated, it affects the vibration of the piezoelectric element which vibrates in the sensor cell 2. [

That is, when the coating thickness is thin, the influence on the performance of the sensing sensor is small.

However, when the coating is applied for a long time or multiple times, the coating thickness becomes thick, and the vibration characteristic of the piezoelectric element and the inherent impedance characteristic value of the sensor cell 2 are changed, and thus the important management item of the sensor performance is RING TIME There arises a problem in the sensitivity of the sensor cell 2 and in the section where the excitation waveform is generated due to the physical vibration of the ultrasonic sensor cell at the time of dispatch.

In other words, there has been a problem of lowering the reliability of a product such as causing a sense of a sensor due to the thickness of the coating as described above.

For the above reason, in the related art, a coating thickness for maintaining the efficient performance of the sensor cell 2 is formed, and a method for preventing the sensation of the sensor cell 2 is searched. However, until now, satisfactory results have not been obtained In fact.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and it is an object of the present invention to provide a sensor cell in which the thickness of a coating layer formed on the front surface of a sensor cell is formed into a shoulder capable of maintaining an efficient performance of a sensor cell, Which can improve the reliability of the vehicle.

According to another aspect of the present invention, there is provided an ultrasonic sensor for a vehicle in which a mounting hole is formed in a vehicle bumper having a through-hole formed therein, A housing; A sensor cell disposed in the through hole and having one end exposed from the through hole; A sound absorbing material filled in the sensor cell; An elastic rubber cap formed in a hollow shape and coupled to an outer circumferential surface of the sensor cell protruded from the through hole and inserted into the mounting hole; A PCB electrically connected to the sensor cell and disposed in the receiving groove; And a potting member filled in the receiving groove to seal one end of the rubber cap and the PCB from the outside.

The sensor cell includes a bottom surface exposed from the through hole and in surface contact with the piezoelectric element 250 on the rear surface; And a side wall portion extending in the vertical direction from the bottom portion, wherein a thickness of the bottom portion is thinner than a thickness of the side wall portion.

And a coating layer on the front surface of the bottom portion to prevent rust from being generated on the front surface of the bottom portion.

The thickness of the coating layer is 40 占 퐉 to 88.6 占 퐉.

The thickness of the coating layer and the bottom portion is thinner than or equal to the thickness of the side wall portion.

The coating layer is formed of any one of aminoalkyd resin, fluorine resin varnish, acrylic resin, and polyurethane resin.

The sensor cell has a connection member, one end of which is electrically connected to the sensor cell, and the other end of which is electrically connected to the PCB.

The potting member is made of silicon.

And a cover member coupled to the other end of the housing to seal the inside of the housing.

The sensor for a vehicle according to the present invention has a coating layer thickness of 40 to 88.6 mu m so as to reduce the sense of the sensor cell due to the thickness of the coating layer formed on the front surface of the sensor cell, Can be improved.

Further, the thickness of the coating film layer and the bottom portion is made thinner or equal to the thickness of the side wall portion, thereby further improving the reliability of the vehicle sensor.

The front surface of the sensor cell, which is one direction of the housing, is exposed to the outside of the housing through the through hole, thereby clearly transmitting and receiving signals transmitted and received from the outside of the housing to the sensor cell.

The housing is separated into two or more parts and assembled, so that various parts such as sensor cell, rubber cap and PCB can be assembled smoothly.

The rubber cap is formed of an elastic material so that it can be easily coupled to the through hole of the housing and the outer circumferential surface of the rubber cap is strongly adhered to the inner circumferential surface of the through hole to effectively prevent the rubber cap from being detached from the through hole.

Such a potting member is used to protect various components housed inside a housing such as a PCB from the outside to thereby airtightly seal various components such as a PCB housed inside the housing with external shock or vibration and foreign substances introduced from the outside into the inside of the housing It is possible to increase the lifetime of the vehicle sensor.

1 is a sectional view of a vehicle sensing sensor according to the prior art;
2 is an exploded perspective view of a vehicle sensing sensor according to an embodiment of the present invention.
3 is a sectional view of a vehicle sensing sensor according to an embodiment of the present invention;

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. And is provided to fully illustrate the scope of the invention to those skilled in the art, and the invention is defined by the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that " comprises, " or "comprising," as used herein, means the presence or absence of one or more other components, steps, operations, and / Do not exclude the addition.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is an exploded perspective view of a vehicle sensing sensor according to an embodiment of the present invention, and FIG. 3 is a sectional view of a vehicle sensing sensor according to an embodiment of the present invention.

2 and 3, a vehicle sensing sensor mounted on a vehicle bumper having a mounting hole formed therethrough includes a housing 100, a sensor cell 200, a sound absorbing material 300, a rubber cap 400, A PCB 500, a potting member 600, and a cover 700.

The housing 100 is a body for housing the PCB 500 and various components and has a through hole 110 formed at one end thereof and an accommodating recess 120 formed at the other end thereof to form a through hole 110, (120) communicating with each other.

The through hole 110 is preferably formed in a circular shape in which one end of the housing 100 communicates with the outside and is communicated with the receiving groove 120 and into which the rubber cap 400 is inserted.

The through hole 110 is a hole in which the sensor cell 200 is disposed and the front surface of the sensor cell 200 protrudes from the housing 100.

The through hole 110 is formed in such a manner that the front surface of the sensor cell 200 is exposed to the outside of the housing 100 to clearly receive or transmit a signal transmitted or received from the outside of the housing 100 to the sensor cell 200. [ can do.

The receiving groove 120 is a hole through which the PCB 500 and various components are received from the outside of the other one side of the housing 100 into the housing 100.

Therefore, the one end direction and the other end direction of the housing 100 are formed into a hollow shape communicating with each other by the through hole 110 and the receiving groove 120.

In addition, the housing 100 may be fabricated by separating the sensor cell 200, the rubber cap 400, and the PCB 500 into two or more pieces so as to smoothly assemble the PCB 500.

The sensor cell 200 senses an object by the generation and reception of ultrasonic waves, and is preferably coupled to the through hole 110 via the rubber cap 400.

The front surface of the sensor cell 200, which is one end of the housing 100, is exposed through the through hole 110.

That is, the sensor cell 200 is exposed to the outside of the housing 100 through the through hole 110, so that a signal transmitted or received from the outside of the housing 100 to the sensor cell 200 can be clearly received or transmitted .

The sensor cell 200 includes a bottom portion 210, a side wall portion 220, a connecting member 230, and a coating layer 240.

The bottom of the bottom portion 210 is exposed from the through hole 110, and the piezoelectric element 250 is in surface contact with the rear surface.

Accordingly, when the piezoelectric element 250 is mounted on the bottom part 210 and an electric signal of a pulse type is applied constantly or irregularly, vibration is generated.

That is, the sensor cell 200 transmits ultrasonic waves due to friction with the bottom part 210 of the sensor cell 200 by the vibration of the piezoelectric element 250, and then reflects the reflected ultrasonic waves, And the received ultrasound signal is transmitted to the PCB 500. [

The side wall portion 220 extends in the vertical direction from the bottom portion 210.

Accordingly, a space is formed in the sensor cell 200 to accommodate the piezoelectric element 250.

On the other hand, the piezoelectric element 250 generates vibration as described above, and generates vibration due to friction with the bottom portion 210.

Therefore, it is preferable that the bottom portion 210 is formed to have a thin thickness, and more specifically, it is formed to be thinner than the sidewall portion 220.

Therefore, the bottom part 210 can more effectively generate vibration due to friction with the piezoelectric element 250, and can transmit and receive ultrasonic waves.

3, one end of the connection member 230 is electrically connected to the sensor cell 200, and the other end of the connection member 230 is electrically connected to the PCB 500 as shown in FIG.

The connection member 230 is preferably coupled to the PCB 500 and the sensor cell 200 by a soldering method.

Further, the connecting member 230 is preferably made of a lead wire or the like.

The coating layer 240 covers the entire surface of the bottom portion 210 to prevent rusting of the entire surface of the bottom portion 210.

The front surface of the bottom portion 210 is exposed to the outside of the through hole 110 and is exposed to the outside of the bumper so that the front surface of the bottom portion 210 is in harmony with the bumper of the vehicle Color.

The coating layer 240 is formed by spraying the sensor cell 200 on the entire surface of the sensor cell 200 after mounting the sensor cell 200 on the jig.

The coating layer 240 may be formed of any one of aminoalkyd resin, fluorine resin varnish, acrylic resin, and polyurethane resin.

However, if the coating layer 240 can be formed on the entire surface of the sensor cell 200, the coating layer 240 may be formed as a film or the like. It can also be formed.

On the other hand, when the thickness D of the coating layer 240 formed on the front surface of the bottom 210 is small, the performance of the sensing sensor is small. However, when the thickness D of the coating layer 240 is large, The vibration of the piezoelectric element 250 and the inherent impedance characteristic value of the sensor cell 200 are changed so that the excitation waveform due to the physical vibration of the ultrasonic sensor cell 200 during RING TIME A problem occurs in the sensitivity of the sensor cell 200).

Therefore, the coating layer 240 formed on the entire surface of the bottom 210 should have an ideal thickness that does not affect the performance of the sensor cell 200.

Applicants have conducted experiments to obtain the above conditions, and the results are shown in the table below.

Experimental example  Ready

The thickness D of the coating layer 240 formed on the front surface of the sensor cell 200 is prepared as shown in Table 1 below.

Experiment 1 : Impedance Property value

According to the experimental results, it can be seen that the change rate of the R 1 value changes by about 40% at the maximum as the thickness D of the coating layer 240 increases.

Therefore, it can be confirmed that the resistance value of the sensor cell 200 is the characteristic value that changes the greatest as the thickness D of the coating layer 240 becomes thicker.

Experiment 2 : Sensor performance

According to the experimental results, it can be seen that the sensitivity change rate of the sensor cell 200 decreases to -25% or less as the thickness D of the coating layer 240 increases.

The experimental results show that as the thickness D of the coating layer 240 formed on the front surface of the sensor cell 200 becomes thicker, the ultrasonic waves of the sensor cell 200 generated by the vibration source of the piezoelectric element 250 are transmitted to the outside This is because it is interfered with.

Experiment 3 : Correlation between Impedance and Sensitivity

According to the experimental results, it can be seen that as the thickness D of the coating layer 240 becomes thicker, the rate of change of the Q value decreases to -20% or less.

The quality of the ideal sensor cell 200 is summarized by the following equation (1).

In the above equation, Q is a quality factor (frequency selection characteristic quality), which represents the ratio of the stored energy to the lost energy.

More specifically, the stored energy is the electrical energy applied to the ceramic element to generate ultrasonic waves in the sensor cell 200, and the energy lost is increased as the thickness D of the coating layer 240 becomes thicker It is loss energy.

Experiment result

As shown in Table 5, as the thickness D of the coating layer 240 increases, the value of R1 increases and as the value of R1 increases, the Q value and the sensor cell 200 ) Decreases.

That is, the thickness D of the coating layer 240 when the rate of change of the Q value is 0% is the most suitable, and the thickness D of the coating layer 240 is increased by 5% It is preferable that the cell 200 is formed to be C (88.6 占 퐉) thinner than the cell of Experimental Example D on the basis of Experimental Example D (102.1 占 퐉) where the sensitivity of the cell 200 is reduced by 5% or more.

In addition, since the front surface of the sensor cell 200 is exposed to the outside of the vehicle, the coating layer 240 also has a function of suppressing the corrosion of the sensor cell 200.

Therefore, the coating layer 240 should satisfy the weatherability evaluation.

Typically, for the satisfaction of the weatherability evaluation, the thickness D of the coating layer 240 should be 40 m or more.

That is, the ideal thickness of the coating layer 240 is preferably 40 占 퐉 to 88.6 占 퐉.

This can reduce the sense of touch of the sensor cell 200 due to the thickness D of the coating layer 240 formed on the front surface of the sensor cell 200, thereby improving the reliability of the vehicle sensor.

The thickness of the coating layer 240 and the bottom portion 210 may be thinner than or equal to the thickness of the side wall portion 220.

Therefore, although the thicknesses of the coating layer 240 and the bottom portion 210 are increased, the sensor cell 200 is formed to be thinner than the thickness of the side wall portion 220, thereby further improving the reliability of the vehicle sensor.

The sound absorbing material 300 reduces the reverberation after the generation of the ultrasonic waves of the piezoelectric element 250, prevents the ultrasonic waves from propagating to the other direction of the housing 100, and prevents unnecessary vibration and noise.

The sound absorbing material 300 is filled in the inner space of the sensor cell 200 through the other open end of the sensor cell 200.

The sound absorbing material 300 is injected into the internal space of the sensor cell 200 and cures to seal the inside of the sensor cell 200.

The rubber cap 400 is formed in a cylindrical shape corresponding to the through hole 110 so as to be coupled to the through hole 110. The outer diameter of the rubber cap 400 is formed to be equal to or larger than the inner diameter of the through hole 110 do.

As a result, when the rubber cap 400 is engaged with the through hole 110, the rubber cap 400 is strongly tightly coupled.

Further, the rubber cap 400 is preferably made of an elastic material.

Therefore, when the rubber cap 400 is coupled to the through hole 110, the rubber cap 400 is elastically deformed and can be easily coupled to the through hole 110.

That is, the rubber cap 400 can easily couple the sensor cell 200 to the inside of the through hole 110, and the outer circumferential surface of the rubber cap 400 is strongly adhered to the inner circumferential surface of the through hole 110, (400) can be prevented from being detached from the through hole (110).

The rubber cap 400 is formed with a seating groove 410.

The seating groove 410 is formed inside the rubber cap 400, and the sensor cell 200 is seated.

To this end, the seating groove 410 is preferably formed in a cylindrical shape corresponding to the sensor cell 200

The seating groove 410 is communicated with the receiving groove 120 through the other side so that the connecting member 230 connected to the sensor cell 200 is exposed in the direction of the receiving groove 120 of the housing 100.

The PCB 500 is mounted on the inside of the housing 100 through the receiving groove 120 of the housing 100 and has a conductor pattern formed on one or both sides of the PCB 500, do.

The PCB 500 is electrically connected to the sensor cell 200 through the connection member 230 and receives ultrasonic signals from the sensor cell 200.

In addition, various circuit elements may be mounted on the PCB 500 by a flip chip method using a conductive adhesive according to the shape of the circuit elements.

After the PCB 500 is inserted into the receiving groove 120 of the housing 100, a potting member 600 made of a liquid is filled in the housing 100.

The porting member 600 is preferably made of a liquid such as silicone and is filled in the housing 100 through the receiving groove 120 of the housing 100 and then hardened.

The porting member 600 blocks various components housed inside the housing 100, such as the PCB 500, from the outside and airtight.

Accordingly, the potting member 600 can protect various components such as the PCB 500 housed in the housing 100 from external shocks or shakes, and protect the components from foreign substances introduced into the interior of the housing 100 from the outside The lifetime of the vehicle detection sensor can be increased.

On the other hand, the potting member 600 is filled with the inside of the housing 100 and is made of a hardened silicon material, which may easily be torn by an external impact.

In order to prevent this, after the potting member 600 is filled in the housing 100 and hardened, the cover 700 is attached to the other end of the housing 100.

The cover 700 is mounted on the other end of the housing 100 after the potting member 600 is filled and hardened in the housing 100.

As a result, the cover 700 can easily protect the potting member 600 from external impact, thereby increasing the service life of the sensor cell 200. [

As described above, since the thickness D of the coating layer 240 is 40 μm to 88.6 μm, the thickness of the coating layer 240 formed on the front surface of the sensor cell 200 It is possible to reduce the sensation of the sensor cell 200 by the sensor D and improve the reliability of the vehicle sensor.

In addition, the combined thicknesses of the coating layer 240 and the bottom portion 210 are formed to be thinner or equal to the thickness of the sidewall portion 220, thereby further improving the reliability of the vehicle sensor.

The front surface of the sensor cell 200 in the direction of one end of the housing 100 is exposed to the outside of the housing 100 through the through hole 110 so that the sensor cell 200 is transferred from the outside of the housing 100 to the sensor cell 200, The signal can be clearly transmitted and received.

The housing 100 is separated into two or more parts and assembled and assembled, so that various components such as the sensor cell 200, the rubber cap 400, and the PCB 500 can be assembled smoothly.

The rubber cap 400 is formed of an elastic material so that it can be easily coupled to the through hole 110 of the housing 100. The outer circumferential surface of the rubber cap 400 is strongly adhered to the inner circumferential surface of the through hole 110, It is possible to effectively prevent the cap 400 from being detached from the through hole 110.

The porting member 600 may be formed by sealing the various components accommodated in the housing 100 such as the PCB 500 and hermetically sealing the components so that the porting member 600 may be mounted on the PCB 100, The parts can be protected from external impact or vibration and foreign substances introduced into the interior of the housing 100 from the outside, thereby increasing the service life of the vehicle detection sensor.

The present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the technical idea of the present invention.

100: housing 110: through-hole
120: receiving groove 200: sensor cell
210: bottom part 220: side wall part
230: connecting member 240: coating layer
300: sound absorbing material 400: rubber cap
410: seating groove 500: PCB
600: Potting member 700: Cover

Claims (9)

1. An ultrasonic sensor for a vehicle mounted on a vehicle bumper having a mounting hole formed therein,
A hollow housing in which a through hole communicating with the outside is formed at one end and a receiving groove is formed at the other end;
A sensor cell disposed in the through hole and having one end exposed from the through hole;
A sound absorbing material filled in the sensor cell;
An elastic rubber cap formed in a hollow shape and coupled to an outer circumferential surface of the sensor cell protruded from the through hole and inserted into the mounting hole;
A PCB electrically connected to the sensor cell and disposed in the receiving groove;
And a potting member filled in the receiving groove to seal one end of the rubber cap and the PCB from the outside
In vehicle detection sensor. 2. The sensor according to claim 1,
A bottom surface exposed from the through hole and having a surface contact with the piezoelectric element on the rear surface;
And a side wall portion extending vertically from the bottom portion,
The thickness of the bottom portion is thinner than the thickness of the side wall portion
In vehicle detection sensor. 3. The method of claim 2,
And a coating layer on the front surface of the bottom portion to prevent rust from being generated on the front surface of the bottom portion
In vehicle detection sensor. The method of claim 3,
The thickness of the coating layer is,
40 占 퐉 to 88.6 占 퐉
In vehicle detection sensor. The method of claim 3,
The thickness of the coating film layer and the bottom portion is thinner than or equal to the thickness of the side wall portion
In-car detection sensor. The method according to claim 3,
And is made of any one of an aminoalkyd resin, a fluorine resin varnish, an acrylic resin, and a polyurethane resin
In vehicle detection sensor. 2. The sensor according to claim 1,
One end of which is electrically connected to the sensor cell and the other end of which is electrically connected to the PCB
In vehicle detection sensor. The method according to claim 1,
Wherein the potting member comprises:
Made of silicon
In vehicle detection sensor. The method according to claim 1,
And a cover member coupled to the other end of the housing to seal the inside of the housing
In vehicle detection sensor.

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