JP2001186002A - Proximity switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proximity switch with low-profile and high reliability, which can self-diagnose its components and realizes space saving. SOLUTION: The proximity switch has a reed switch 11 connected in parallel with one of resistor components 21, 22 connected in series and a printed circuit board 31 on which the resistor components 21, 22 and the reed switch 11 are mounted. The proximity switch captures a change in a current flowing to the resistor components 21, 22 by turning on/off the contacts of the reed switch 11 to identify operation of the resistor components 21, 22 and the reed switch 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a proximity switch used as a sensor for detecting an electric signal.
The present invention belongs to a proximity switch which is mounted on a vehicle having a seat belt and a buckle device to which the seat bell is detachably attached, and which is applied to a buckle device for electrically detecting whether or not the seat belt is worn.

[0002]

2. Description of the Related Art Conventionally, a seat of a vehicle is provided with a seat belt and a buckle device to which the seat bell is detachably attached in order to protect an occupant. Also,
Vehicles must have an SR to protect occupants in the event of a collision.
The C airbag system is installed.

The airbag system instantly inflates the airbag when a vehicle collides and reduces the impact received by the occupant. The airbag system protects the occupant by using it together with a seat belt and a buckle device. is there.

In an airbag system, the safety of an occupant can be enhanced by changing the explosion strength of the airbag depending on whether or not a seat belt and a buckle device are worn.

[0005] Therefore, the presence or absence of the seat belt and the buckle device needs to have a high detection accuracy in conjunction with the airbag.

As shown in FIG. 11, a conventional buckle device generally has a tongue 200 provided at one end of one seat belt and a buckle provided on the other seat belt for inserting and removing the tongue 200. And a main body 100.

The buckle body 100 includes a latch plate 401 for fixing the tongue 200, a buckle base 101 on which the latch plate 401 is supported, and a buckle base 1.
01, a slider 301 that slides by inserting and removing the tongue 200 and moves in accordance with this movement, a slider switch (not shown) that detects the state of insertion and removal of the tongue 200 with respect to the buckle body 100, Handle side tongue portion 2 of tongue 200 arranged slidably along the insertion direction of tongue 200
An ejector 302 is slid by being gripped by hand and inserting the lock-side tongue portion 201 and urged by the lock-side tongue portion 201.

The slider switch is arranged corresponding to the movement locus of the ejector 302 and has a fixed contact (not shown).
, And a moving contact (not shown) provided between the fixed plate 303 and the ejector 302 and provided on the slider 301.

The slider switch slides along the fixed contact, and when the ejector 302 moves, the moving contact and the fixed contact come into contact with each other.

[0010]

However, the conventional buckle device normally detects whether or not the moving contact and the fixed contact of the slider switch have come into contact with each other. Due to dust etc.
If the fixed contact and the moving contact are short-circuited, a malfunction may occur.

Further, when liquid or the like is interposed between the moving contact and the fixed contact, there is a problem that the ejector 302 does not move or a contact failure occurs at the moving contact and the fixed contact.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to make it possible to appropriately and surely determine and identify the state of normal or abnormal, and to realize a thin and space-saving component capable of performing a self-diagnosis function of parts. It is an object of the present invention to provide a realized high reliability proximity switch.

[0013]

According to the present invention, in a proximity switch for identifying an operation state by a change in a current value, at least two resistance parts connected in series and one resistance part connected in parallel to the resistance part. A reed switch, and a printed circuit board on which the resistance component and the reed switch are mounted, wherein a change in the value of a current flowing through the resistance component is captured by turning on / off a contact of the reed switch. A proximity switch is obtained which is characterized by identifying the operating state of the switch.

[0014]

The proximity switch according to the present invention is used as a sensor in a buckle device. The proximity switch is connected to a reed switch and a resistor in order to enable appropriate and reliable judgment and identification of whether the component is normal or abnormal. The components and the circuit are configured on the same printed circuit board, and the operating state of each is read by a change in current value.

Reed switch 11 sealed with a glass tube
A printed circuit board having a notch in the periphery of the glass tube, and a resistor component arranged in parallel with the reed switch, and after soldering a wire harness to the printed circuit board 31 and housing it in an outer case, The inside of the outer case is filled with an insulating resin.

The reed switch has a contact sealed with a glass tube, has a high environmental resistance, and has a protective structure for preventing cracking of the glass tube by filling with an outer case and a resin.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a proximity switch according to the present invention will be described below. FIG. 1 shows a first embodiment of a proximity switch.

Referring to FIG. 1, a proximity switch 1A according to the first embodiment includes a first resistance component 21 and a second resistance component 21.
Resistance component 22 and first and second resistance components 21 and 22
And a long printed board 31 on which the first and second resistance components 21 and 22 and the reed switch 11 are mounted.

In the proximity switch 1A, a change in the value of the current flowing through the first and second resistance components 21 and 22 is captured by turning on and off the contact of the reed switch 11, and the first and second resistance components 21 and 22 are captured. And the operating state of the reed switch 11 is identified.

Resistance components 21 and 22, reed switch 11
The printed circuit board 31 is housed in a rectangular cylindrical outer case 25. In the outer case 25, the first and second
The insulating resin 61 filled with the resistance components 21 and 22 and the reed switch 11 is provided.

In the reed switch 11, opposing reed pieces 11a and 11b are hermetically sealed by a glass tube (insulating container) 12 having the same diameter as a whole. Insulating resin 61
Is the first and second resistance components 2 together with the outer case 25.
1 and 22 and the reed switch 11 are protected.

As shown in FIG. 2, a notch 31a is formed in the printed circuit board 31 at a position corresponding to the reed switch 11 so as to keep the mounting height of the reed switch 11 low. When the notch 31a is formed not only at the position corresponding to the reed switch 11 but also at the position corresponding to the first and second resistance components 21 and 22, the first and the second notch 31a are formed by the notch 31a. The mounting height of the second resistance components 21 and 22 can be reduced.

In FIG. 2, when the reed switch 11, the first resistive component 21, and the second resistive component 22 are mounted on the printed board 31, the printed board 31
Notch 31 so as not to contact the glass tube 12
It can be seen that a has a notch shape by a.

In addition, the printed circuit board 31 is provided with the first and second resistance components 21 and 22 and the reed switch 11 so that the mounting height of the reed switch 11 is kept low in place of the cutout portion 31a. Even if a punched portion (not shown) is formed at a position corresponding to the reed switch 1, the same effect as the cutout portion 31a can be obtained.

As a specific example of the first and second resistance components 21 and 22 for detecting such a change in the current value, it is possible to recognize and display using a light emitting diode, a buzzer, or the like. In addition, the first and second resistance components 2
For example, chip resistors 1 and 22 may be used in order to keep the mounting height on the printed board 31 low.

As shown in FIG. 2, a pattern wiring 32 is provided on one end of the first resistance component 21 on the printed circuit board 31.
And a second land 82b connected to the second resistive component 22 via the pattern wiring 32. The first and second lands 72a and 72b are provided on one longitudinal end surface of the printed circuit board 31. A wire harness 4 is provided on each of the first and second lands 72a and 72b.
1a and 41b (see FIG. 1) are connected.

The printed board 31 and the printed board 3
1, the first and second resistance components 21 and 22 and the reed switch 11 are, as shown in FIG.
5 and the inside of the outer case 25 is filled with an insulating resin 61. At this time, it is desirable to use a relatively flexible and low-hardness reed switch 11 in order to compensate for the defect that the glass tube 12 is cracked by external stress.

The reed switch 11 has a contact sealed with a glass tube 12, is excellent in environmental resistance, and is prevented from cracking by being filled with an outer case and an insulating resin. It becomes a protection structure.

Next, the circuit configuration of the proximity switch 1A is shown in FIG.
This will be described with reference to FIG. Referring to FIGS. 2 and 3, first resistive component 21 and second resistive component 22 are connected in series between DC power supplies, and reed switch 11 and second resistive component 22 are connected and arranged in parallel. Then, the resistance component 21 is arranged in series with respect to the parallel position of the reed switch 11 and the second resistance component 22.

At this time, the power supply voltage is set to V (volt) and the first
The resistance value of the resistance component 21 is R1 (ohm), the resistance value of the second resistance component 22 is R2 (ohm), and the reed switch 1
Let us consider a current value I (ampere) due to a change in the operating state when the contact resistance value of 1 is R3 (milliohm).

Normally, when the reed switch 11 is in the open state, the current value Ia (ampere) in the open state is
Ia = (R1 + R2) / V. Next, the current value Ib (ampere) when the reed switch 11 is closed by the influence of the external magnetic field is Ib = (R1 + (((1 / R
2) + (1 / R3)) the reciprocal)) / V.

Here, the resistance value R4 in the parallel circuit = (1 /
The reciprocal of (R2) + (1 / R3) becomes a value close to zero (ohm) because the contact resistance value of the reed switch 11 is small. The operation state of the reed switch 11 can be detected from the change between the current value Ia and the current value Ib.
Further, when the wire harnesses 41a and 41b are disconnected, no current flows, so that the current value Ic = 0 at the time of the disconnection.
Further, the current value Id when the mounted components such as the reed switch 11 and the first and second resistance components 21 and 22 are short-circuited can be read.

FIG. 4 shows a proximity switch according to a second embodiment of the present invention. The second embodiment uses substantially the same components as those of the first embodiment described with reference to FIG. The proximity switch 1B in the second embodiment differs from the first embodiment described with reference to FIG. 1 in the configuration described below.

Referring to FIG. 4, one end of printed board 31 protrudes outward from one end of exterior case 25 and insulating resin 61, and one end of printed board 31 protruded outward. The first and second lands 72
a and 72b are provided. First and second lands 7
Wire harnesses 41a and 41b are connected to 2a and 72b by soldering. Further, the first and second lands 72 a and 72 b and one end surface of the printed board 31 protruding outward are covered with an additional insulating resin 69.

In this proximity switch 1B, as in the first embodiment, the reed switch 11 has a contact sealed with a glass tube 12, has excellent environmental resistance, and has an outer case 25. Since the inside is filled with the insulating resin 61, the glass tube 12 has a protection structure in which cracking of the glass tube 12 is prevented.

In the proximity switch 1B shown in FIG. 4, the wire harness 41 configured as shown in FIG.
a and 41b are soldered to the first and second lands 72a and 72b, and then an additional insulating resin 69 is applied.

FIG. 5 shows a proximity switch according to a third embodiment of the present invention. Note that the third embodiment uses substantially the same components as those of the first embodiment described with reference to FIG. 1, and therefore, the same portions are denoted by the same reference numerals and description thereof will be omitted. The proximity switch 1C according to the third embodiment differs from the first embodiment described with reference to FIG. 1 in the configuration described below.

Referring to FIG. 5, a proximity switch 1C according to the third embodiment includes first and second resistance components 2
In order to protect the reed switches 11 and 22 and the printed circuit board 31, first and second resistance components 21 and 22 are provided.
The reed switch 11 and the printed circuit board 31 are integrally formed of an insulating resin 77.

Therefore, there is no outer case 25 in the first embodiment. As described above, if the first and second resistance components 21 and 22, the reed switch 11, and the printed board 31 are integrally formed with the insulating resin 77, the number of members and the number of work steps can be reduced. Further, a protective structure is provided in which the glass tube 12 of the reed switch 11 is prevented from breaking.

FIG. 6 shows a proximity switch according to a fourth embodiment of the present invention. Note that the fourth embodiment uses substantially the same components as those of the first and third embodiments described with reference to FIGS. 1, 4 and 5, and therefore, the same portions are denoted by the same reference numerals. And the description is omitted. The proximity switch 1D according to the fourth embodiment is different from the third embodiment described with reference to FIG. 5 in the configuration described below.

Referring to FIG. 6, one end of printed circuit board 31 is protruded outward from one end of insulating resin 77 by integral molding, and is formed on one end surface of printed circuit board 31 protruded outward. The first and second lands 72
a and 72b are provided. First and second lands 7
Wire harnesses 41a and 41b are connected to 2a and 72b. Further, the first and second lands 72
a, 72b, printed circuit board 31 protruding outward
Is covered with an additional insulating resin 79 integrally molded.

In the proximity switch 1D shown in FIG.
After the wire harnesses 41a and 41b are soldered to the first and second lands 72a and 72b based on the circuit configuration described above, an additional insulating resin 79 is applied.

In the proximity switch 1D, similarly to the third embodiment, the outer case 25 described with reference to FIG.
There is no. Thus, the first and second resistance components 21 and
2. The reed switch 11 and the printed circuit board 31 are integrally molded with the insulating resin 77, and at the same time, the additional insulating resin 79
Is formed, the number of members and the number of work steps can be reduced. Further, a protective structure is provided in which the glass tube 12 of the reed switch 11 is prevented from breaking.

By the way, each of the proximity switches 1A to 1D described in the first to fourth embodiments is incorporated in a buckle device as shown in FIGS. It is possible to appropriately and reliably determine and identify whether the state is normal or abnormal.

FIG. 7 shows a state in which one of the proximity switches 1A and 1B described with reference to FIGS. 1 and 4 is incorporated. FIG. 8 shows a state in which one of the proximity switches 1C and 1D described with reference to FIGS. 5 and 6 is incorporated. FIG. 9 is a sectional view showing a state in which one of the proximity switches 1A and 1B described with reference to FIGS. 1 and 4 is incorporated.

Here, the buckle device has the same structure as in FIGS. 7 to 9 and will be described at the same time. explain.

Referring to FIGS. 7 to 9, the buckle device generally includes a tongue 200 provided at one end of one of the seat belts and a locking tongue portion 20 of the tongue 200.
And a buckle body 100 provided on the other seatbelt for inserting and removing the first seatbelt.

The buckle body 100 includes a latch plate 401 for fixing the tongue 200, a buckle base 101 on which the latch plate 401 is supported, and a buckle base 1.
01 and the tongue portion 2 on the handle side of the tongue 200 with respect to the buckle body 100.
02, the lock side tongue portion 201 is inserted into the buckle main body 100 by inserting the lock side tongue portion 201 into the buckle body 100, and the proximity switch (in FIG. 9, the proximity switch 1A or 1B shown in FIG. 1 or FIG. An ejector 302 is slidably disposed along the insertion direction of the portion 201, is slid by the insertion of the tongue 200, and is urged by the tongue 200.

The proximity switch 1A (or any one of the proximity switches 1B, 1C, 1D) is arranged corresponding to the movement locus of the ejector 302. Ejector 302
Has a permanent magnet 5 so that it moves horizontally and faces the contact.
01 is provided. When the ejector 302 moves, the contact of the reed switch 11 comes into contact.

The proximity switch 1A (or any one of the proximity switches 1B, 1C and 1D) has a buckle base 10
1 housed. The buckle device of FIG. 7 shows a state in which the proximity switch of FIGS. 1 and 4 is incorporated in a buckle base 101. The buckle device of FIG. 8 shows a state in which the integrally formed proximity switch of FIGS. 2 and 6 is incorporated in a buckle base 101.

The operation will be described with reference to FIG. 10. When the lock-side tongue portion 201 is inserted into or removed from the buckle main body 101, the permanent wood magnet 501 attached to the ejector 302 slides, and the reed switch 1 is turned on.
Turn 1 on and off. The ejector 302 is attached to the latch plate 401 by a spring 330, and can be slid by the spring 330.

That is, the ejector 302 of the latch plate 401
When the permanent magnet 501 attached to the slider slides and approaches a certain distance, the reed switch 11 is turned on by magnetic attraction. Conversely, when the lock-side tongue 201 is detached and the permanent magnet 501 attached to the ejector 302 is separated from the reed switch 11, the magnetic attraction force is lost,
The reed switch 11 turns off.

The proximity switches 1C and 1D shown in FIGS. 5 and 6 are both integrally formed. Instead of the proximity switches 1C and 1D, the wire harnesses 41a and 41b shown in FIG. After the printed circuit board 31 to which is connected is directly incorporated into the buckle base 101, the periphery thereof may be covered with the insulating resin 62.

[0054]

As described above in detail with reference to the embodiment, according to the proximity switch of the present invention, the reed switch and the resistance component are formed on a printed circuit board to operate the reed switch. Not only the state is stabilized, but also self-diagnosis in which the mounted components such as the reed switch 11 and the first and second resistive components 21 and 22 can accurately read a failure state such as short-circuit or wire harness disconnection detection by a change in current value. Functions can be added.

Further, since the reed switch is mounted on the printed circuit board, stable operation characteristics are exhibited. Further, the device mounted on the printed circuit board is filled with an insulating resin resin in the outer case, or the insulating property is improved. Excellent protection structure can be obtained because it is integrally molded with resin.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a proximity switch according to the present invention.

FIG. 2 is a plan view showing a state in which the proximity switch of FIG. 1 is mounted on a printed circuit board.

FIG. 3 is a diagram showing an example of a circuit configuration of the present invention.

FIG. 4 is a perspective view showing a proximity switch according to a second embodiment of the present invention.

FIG. 5 is a perspective view illustrating a proximity switch according to a third embodiment of the present invention, in which components of the proximity switch are seen through;

FIG. 6 is a perspective view illustrating a proximity switch according to a fourth embodiment of the present invention, in which components of the proximity switch are seen through;

FIG. 7 is a plan view showing a state in which any of the proximity switches of FIGS. 1 and 4 is incorporated into a buckle base and a tongue is inserted.

FIG. 8 is a plan view showing a state where one of the proximity switches shown in FIGS. 5 and 6 is incorporated into a buckle base and a tongue is inserted.

FIG. 9 is a side sectional view showing a state where any one of the proximity switches shown in FIGS. 1 and 4 is incorporated in a buckle device.

FIG. 10 is a schematic side view for explaining movements of a proximity switch and an ejector of the buckle device shown in FIG. 9;

FIG. 11 is a side sectional view showing a conventional buckle device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Reed switch 11a, 11b Lead piece 12 Glass tube 21, 22 Resistance component 25 Outer case 31 Substrate 41a, 41b Wire harness 61, 77 Insulating resin 69, 79 Additional insulating resin 72a, 72b Land (pattern) 100 Buckle device 101 Buckle base 102 Buckle cover 201 Lock side tongue 202 Handle side tongue 301 Slider 302 Ejector 303 Fixing plate 401 Latch plate 501 Permanent magnet

Claims (5)

[Claims] 1. A proximity switch for identifying an operation state based on a change in a current value, wherein at least two resistance components connected in series, a reed switch connected in parallel to one of the resistance components, A printed circuit board on which a reed switch is mounted, wherein a change in a current value flowing through the resistance component is captured by turning on / off a contact of the reed switch to identify an operation state of the resistance component and the reed switch. Features proximity switch. 2. The proximity switch according to claim 1, wherein
A proximity case, comprising: an outer case that houses the resistance component, the reed switch and the printed board; and an insulating resin that fills and protects the resistance component and the reed switch in the outer case. switch. 3. The proximity switch according to claim 1, wherein
A proximity switch, comprising: the resistance component, the reed switch, and an insulating resin formed integrally with the printed board so as to protect the reed switch and the printed board. 4. The proximity switch according to claim 2, wherein the printed circuit board corresponds to at least one of the resistance component and the reed switch so as to keep the mounting height of the resistance component and the reed switch low. A proximity switch having a notch in a position. 5. The proximity switch according to claim 2, wherein the printed circuit board corresponds to at least one of the resistance component and the reed switch so as to keep the mounting height of the resistance component and the reed switch low. A proximity switch having a punched portion at a position.