JP2001032628A - Catch preventing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent foreign matter from getting caught between a movable body and its frame, acting only in the closing motion of the movable body such as a window pane or a door. SOLUTION: In order to prevent foreign matter 8 from getting caught between an automatically opened/closed movable body 2 such as a window pane or a door 1 and its frame, a sensor electrode 4 is installed at a specified part of the frame, and an electrostatic capacity detecting part 5 is electrically connected to the sensor electrode 4 to output a signal corresponding to electrostatic capacity formed between the sensor electrode 4 and the foreign object 8. This signal is processed by a signal processing part 6, and upon detecting the foreign matter 8 caught between the frame and the movable body 2, an insertion preventing command is outputted to stop the motion of the movable body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-jamming device and method, and more particularly, to an anti-jamming device that capacitively detects the presence of an jam using an imaginary short-circuited operational amplifier. About the method.

[0002]

2. Description of the Related Art In order to prevent a hand or a finger from being caught between an electric window glass and a window frame of a vehicle such as an automobile,
Various proposals have been made so far. For example, an anti-jamming device for a vehicle window of a vibration application type applies a vibration in parallel to a plate surface of a window glass from a vibration applying device provided at one end of the window glass, and transmits a surface wave transmitted on an edge of the window glass to another of the window glass. It is configured to be detected by a vibration detection sensor provided at the end, and it is determined whether or not the surface wave applied by the vibration applying device is interrupted in the middle of propagating along the edge of the window glass. The presence or absence of contact of the foreign matter between the upper end of the glass and the window frame is detected, and the window glass is stopped when the contact is detected.

Further, in the piezoelectric sensor type anti-jamming device, a piezoelectric sensor is mounted on a peripheral portion of an opening / closing portion such as a window glass or a door, and an object is moved to the peripheral portion of the opening / closing portion based on a signal output from the piezoelectric sensor. It is configured to detect whether or not the contact has been made, and to control the opening and closing operation of the opening and closing unit. When the contact of the object is detected by the piezoelectric sensor, the operation of the opening and closing member is stopped.

[0004]

However, in such a conventional anti-jamming device for a vehicle window, regardless of the vibration applying type or the piezoelectric sensor type, an object is applied to the window glass while the window or door is being opened. If touched, there is a drawback that a malfunction occurs in which the opening operation of the window glass stops.

The present invention has been proposed to solve these disadvantages, and an object of the present invention is to operate only when a movable body such as a window glass or a door which is automatically opened and closed is closing. Another object of the present invention is to provide a device and a method for preventing a foreign object from being inserted between the movable body and its frame.

[0006]

In order to achieve the above object, according to the present invention, a movable body such as a window glass or a door which is automatically opened and closed, and the movable body which is closed when a certain space is closed. A pinching prevention device for preventing a foreign object from being pinched between a contact body in contact with a body, and is electrically connected to a sensor electrode made of a conductor provided at a predetermined portion of the contact body. A capacitance detection unit that outputs a signal corresponding to capacitance formed between the sensor electrode and the foreign matter, and receives the signal output from the capacitance detection unit,
A signal processing unit that issues a pinch prevention command when detecting that a foreign object has been pinched between the contact body and the movable body, and a pinch prevention device, comprising:
I will provide a.

Preferably, the contact body is a frame such as a window glass or a door. The capacitance detection unit has an inverting input terminal, a non-inverting input terminal, and an output terminal, the output terminal and the inverting input terminal are connected by a feedback impedance, and the inverting input terminal and the non-inverting input An operational amplifier whose terminal is in an imaginary short state, an oscillation circuit that applies a sine wave signal to the non-inverting input terminal, one end is connected to the inverting input terminal, and the other end is connected to the sensor electrode. Signal line, and a shield line surrounding at least a part of the signal line and connected to the non-inverting input terminal, wherein the operational amplifier has a distance between the sensor electrode and the detection target. It is desirable to output a voltage including the frequency of the sine wave signal.

The signal processing section compares the peak value with a predetermined threshold value, and detects that the former has exceeded the latter, and issues the pinch prevention command. And a comparing / detecting circuit.

Here, it is preferable that the surface of the contact body having the sensor electrode is covered with a flexible insulator such as resin or rubber. Further, in another invention, there is provided a method for preventing foreign matter from being caught between a movable body that is automatically opened and closed, such as a window glass and a door, and a contact body such as a frame thereof, wherein the contact body includes Detecting a capacitance formed between a conductive sensor electrode and a foreign substance installed at a predetermined portion of; a step of outputting a signal corresponding to the detected capacitance; and Based on the signal, a step of detecting whether or not a foreign substance has been caught between the contact body and the movable body, and a step of issuing a pinch prevention command when detecting that the foreign substance has been caught,
A method for preventing pinching is provided.

[0010]

The capacitance formed between the sensor electrode and the foreign matter is determined by the distance between them. Upon receiving this capacitance, the capacitance detection unit outputs a signal corresponding to the distance between the sensor electrode and the foreign matter. A predetermined threshold value corresponding to the minimum distance between the sensor electrode and the foreign matter when it is determined that the foreign matter has been caught is set in the signal processing unit.

[0011]

FIG. 1 is a block diagram schematically showing a configuration of an embodiment of an anti-jamming device according to the present invention. The anti-jamming device for a vehicle window in a vehicle employing a power window system is shown. 1 shows a schematic configuration for implementing the present invention. Referring to FIG.
Is driven by a vehicle window opening and closing device 3 to be opened and closed. In order to prevent pinching, it is necessary to stop the operation of the vehicle window opening / closing device 3 when detecting that a foreign object such as a hand or a finger is pinched between the window glass 2 and the window frame. For this purpose, a sensor electrode 4 of an appropriate shape made of a conductor is installed at an appropriate position on the edge of the window frame facing the window glass 2, and the sensor electrode 4 is connected to the capacitance detection unit 5. The capacitance detection unit 5 converts a physical quantity detected by the sensor electrode 4 into an electric signal, and provides the electric signal to the signal processing unit 6. The signal processing unit 6 determines the presence or absence of an abnormal state based on the electric signal received from the capacitance detecting unit 5, and issues a stop command to the vehicle window opening and closing device 3 when determining that an abnormal state has occurred. To stop the operation.

The sensor electrode 4 is for forming a capacitance between the sensor electrode 4 and a foreign substance near the window frame, and a portion facing the window glass is covered with a covering member 7 made of an elastic insulator. ing. When the foreign matter can be regarded as a semi-conductor such as a human body, the covering member is preferably an insulator because if such a conductor is in direct contact with the sensor electrode, the foreign matter cannot be detected. In order to minimize the damage to the substrate, it is preferable to use a material such as elastic or flexible resin such as rubber or chemical fiber as described above. In addition, the sensor electrode 4
In order to prevent the deterioration of the sensor electrode 4 over time, it is also desirable that the surface of the sensor electrode 4 be waterproofed.

If it is assumed that a foreign substance 8 is caught between the window glass 2 and the window frame while the window glass 2 is being closed, the foreign substance 8 approaches the sensor electrode 4 together with the window glass 2,
Accordingly, the capacitance formed between the sensor electrode 4 and the foreign matter 8 increases. An electric signal corresponding to the increased capacitance is provided from the capacitance detection unit 5 to the signal processing unit 6, and the signal processing unit 6 constantly compares the amplitude of the provided electric signal with a predetermined threshold. When the foreign matter 8 comes closer to the sensor electrode 4 and comes into contact with the covering member 7,
The amplitude of the electric signal output from the capacitance detector 5 exceeds a predetermined threshold. The signal processing unit 6 detects this and determines that an abnormal state has occurred, and issues a stop command to stop the operation of the vehicle window opening / closing device 3. However, when the window glass only comes into contact with the covering member 7, it is determined to be abnormal. Is not determined, and no stop command is issued.

FIG. 2 shows a state in which the foreign substance 8 is sandwiched between the window glass 2 and the window frame and comes to a position where it comes into contact with the covering member 7. In the embodiment shown in FIG. 1, foreign matter 8 is applied to sensor electrode 4 with thickness L of covering member 7.
When approaching to a distance equal to
Is defined as a reference capacitance. Therefore, a value equivalent to the amplitude of the electric signal corresponding to the reference capacitance is set as a threshold value in the signal processing unit 6, and when the foreign substance 8 approaches the sensor electrode 4 up to the distance L, the above-described stop is performed. An instruction is issued. Thus, the pinch of the foreign matter 8 is detected before the window glass 2 is completely closed, and the window glass 2 is detected.
Can be stopped to reliably prevent foreign matter from being caught.

FIG. 3 is a diagram for explaining the configuration of the capacitance detecting unit 5 and the signal processing unit 6, and also shows the connection relationship between the sensor electrode 4 and the vehicle window opening / closing device 3. The capacitance detection unit 5 includes a capacitance detection circuit 51 including an imaginary short-circuited operational amplifier and an oscillation circuit 52. The input of the capacitance detection circuit 51 is a shielded signal line. 9 and is electrically connected to the sensor electrode 4. Accordingly, the capacitance detection circuit 51 uses the sine wave signal from the oscillation circuit 52 to trap the capacitance and the foreign matter when no foreign matter is sandwiched between the window glass 2 and the sensor electrode 4. It outputs an electric signal Vout corresponding to the capacitance between the sensor electrode 4 and the foreign matter at the time of the contact. This will be described later with reference to FIG.

On the other hand, the signal processing section 6 includes a peak value holding circuit 61 for holding a peak value of the electric signal Vout from the capacitance detecting circuit 51, and a peak value given from the peak value holding circuit 61 for the reference capacitance. And a comparison / detection circuit 62 that generates a stop command when detecting that the peak value exceeds the threshold value by comparing with a predetermined threshold value corresponding to the amplitude of an electric signal corresponding to the stop command. When it is
The vehicle window opening / closing device 3 stops its operation and stops the movement of the window glass 2.

Here, the configuration and operation of the capacitance detection circuit 51 will be described with reference to FIG. The capacitance detection circuit 51 includes an operational amplifier 511, which is an operational amplifier having extremely large input impedance and gain. Output terminal and inverting input terminal (-) of operational amplifier 511
And a feedback resistor 512 is connected between the
1 has negative feedback. Further, the operational amplifier 51
One inversion input terminal (-) is connected to one end of a signal line 9, and the other end of the signal line 9 is connected to the sensor electrode 4. On the other hand, the non-inverting input terminal (+) of the operational amplifier 511 is connected to the output terminal of the oscillation circuit 52 for generating a sine wave signal and the signal line 9.
Is connected to a shield wire 10 surrounding at least a part of the periphery of the wire.

At least a part of the signal line 9 is connected to the shield line 1
The reason why the signal is surrounded by 0 is to prevent unnecessary signals such as external noise from being guided to the signal line 9 by the shield line 10, and the shield line 10 is not grounded.

As described above, the operational amplifier 511 has extremely large input impedance and gain, and the operational amplifier 511 has a negative feedback loop formed through the feedback resistor 512.・
It is in a short state. That is, the voltage difference between the inverting input terminal (-) and the non-inverting input terminal (+) of the operational amplifier 511 is substantially zero. Therefore, the signal line 9 and the shield line 10 are at the same potential, and the stray capacitance generated between the signal line 9 and the shield line 10 can be canceled. This is true regardless of the length of the signal line 9. Therefore, the output voltage output to the output terminal does not change due to a change in the stray capacitance generated between the signal line 9 and the shield line 10 due to movement, bending, folding, or the like of the signal line 9. Thus, the capacitance formed by the sensor electrode 4 can be detected with high sensitivity.

Here, the foreign matter 8 is located between the window glass 2 and the window frame.
Is assumed, and an electric signal output from the operational amplifier 511 when a sine wave signal is generated from the oscillation circuit 52 is expressed as Vout.

[0021]

Vout = (1 + jωCs · Rf) · Vin (1) Here, Vin is the amplitude of the sine wave signal generated from the oscillation circuit 52, ω is the angular frequency of the sine wave signal, Rf is the resistance value of the feedback resistor 512,
s is the value of the capacitance formed between the sensor electrode 4 and the foreign matter 8. At this time, if the distance between the sensor electrode 4 and the foreign matter 8 is d, the distance between Cs and d is

[0022]

The following relationship holds: Cs = ε · A / d (2) Here, ε is the dielectric constant of a substance existing between the sensor electrode 4 and the foreign matter 8, and A is the area of a part of the sensor electrode 4 which is considered to face the foreign matter 8.

By substituting equation (2) into equation (1), equation (1) becomes

[0024]

## EQU3 ## Vout = (1 + jωRf ・ εA / d) ・ Vin (3) This equation shows that the voltage Vout output from the capacitance detection circuit 51 has a value corresponding to the distance d between the sensor electrode 4 and the foreign matter 8, that is, the output of the capacitance detection circuit 51 This shows that a voltage Vout corresponding to the distance between the sensor electrode 4 and the foreign matter 8 appears.

When d = L, in other words, when the foreign matter 8 comes into contact with the coating member 7, the dielectric constant ε is substantially equal to the dielectric constant ε 'of the coating member 7. Therefore, assuming that the electric signal output from the capacitance detection circuit 51 at this time is Vout ′, Vout ′ is calculated by using the above equation (3).

[0026]

Vout ′ = (1 + jωRf · ε ′ · A / L) · Vin (4) Using this, the comparison / detection circuit 6
A threshold value set to 2 can be obtained. in this case,
Since the area A of the portion of the sensor electrode 4 which is considered to be opposed to the foreign matter 8 varies depending on the type and shape of the foreign matter 8, the area A
Is determined on the assumption that the smallest foreign object is predicted to be interposed.

When a conductor is present near the sensor electrode 4, the conductor also forms a stray capacitance with the sensor electrode 4, so that the influence of such a stray capacitance is removed as much as possible, and The capacitance detection circuit 51 is connected to the sensor electrode 4 and the foreign substance 8
It is desirable that a conductor existing around the sensor electrode 4 be electrically connected to the shield wire 10 in order to operate accurately based on the capacitance Cs between the shield wire 10 and the shield electrode 10. In this case, the conductor around the sensor electrode 4 has the same potential as the sensor electrode 4 and does not affect the operation of the capacitance detection circuit 51. For example, a negative feedback loop may be formed by a capacitance, a coil, and the like in addition to a feedback resistor in the capacitance detection circuit, and a peak holding unit may not be used in the signal processing unit.

Although one embodiment of the anti-jamming device according to the present invention has been described above, the present invention is not limited to such an embodiment. For example, this invention not only prevents pinching for car windows,
The present invention can also be applied to prevent a foreign object from being caught between a movable body such as a door that is automatically opened and closed and a frame thereof. At this time, the sensor electrode is installed at an appropriate position of the frame where it is predicted that the sensor electrode will be pinched with the movable body. Further, when it is determined that a foreign object has been caught, the movable body may be moved in the opposite direction instead of stopping the movement of the movable body.

[0029]

As will be understood from the above description of the present invention with reference to the illustrated embodiment, the inventions of claims 1 and 6 are intended to close a movable body such as a door or a window glass. This has the effect that pinching can be prevented only in such a case.

According to the second aspect of the present invention, a voltage accurately corresponding to the capacitance formed between the sensor electrode and the foreign matter can be obtained, for example, in the order of femtofarad (one thousandth of picofarad). Even if it is very small, the capacitance can be converted with high accuracy, so that the movement of the movable body can be accurately controlled according to the distance between the sensor electrode and the foreign matter. To play.

According to the third aspect of the invention, there is an effect that the movement of the movable body can be controlled only when the foreign matter is caught and the distance between the foreign matter and the sensor electrode reaches a predetermined value.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an embodiment of an anti-jamming device according to the present invention.
1 shows a configuration when applied to a system.

FIG. 2 is a diagram illustrating a state in which a foreign object is sandwiched.

FIG. 3 is a block diagram showing a configuration of the anti-jamming device shown in FIG. 1 in detail.

FIG. 4 is a diagram schematically showing a configuration of a capacitance detection circuit shown in FIG. 3;

[Explanation of symbols]

1: door, 2: window glass, 3: car window opening / closing device,
4: sensor electrode, 5: capacitance detecting unit, 6: signal processing unit, 7: covering member, 8: foreign matter, 9: signal line, 1
0: shield wire, 51: capacitance detection circuit, 511:
Operational amplifier, 512: feedback resistor, 52: oscillation circuit,
61: peak value holding circuit, 62: comparison / judgment circuit.

Claims (6)

[Claims] 1. An anti-jamming device for preventing a foreign object from being jammed between a movable body such as a window glass and a door which is automatically opened and closed, and a contact body in contact with the movable body. A capacitance detection unit that is electrically connected to a sensor electrode provided at a predetermined portion of the device and outputs a signal corresponding to a capacitance formed between the sensor electrode and a foreign substance; A signal processing unit that receives the signal output from the detection unit, and issues a pinch prevention command when detecting that a foreign object has been pinched between the contact body and the movable body. Anti-trapping device. 2. The inverting input terminal includes an inverting input terminal, a non-inverting input terminal, and an output terminal, wherein the output terminal and the inverting input terminal are connected by a feedback impedance. An operational amplifier having an imaginary short circuit between the input terminal and the non-inverting input terminal; an oscillation circuit for applying a sine wave signal to the non-inverting input terminal; one end connected to the inverting input terminal; A signal line connected to the sensor electrode; and a shield line surrounding at least a part of the signal line and connected to the non-inverting input terminal, wherein the operational amplifier includes the sensor electrode and the detection target. The anti-jamming device according to claim 1, wherein a voltage including a distance to an object and a frequency of the sine wave signal is output. And a holding circuit for holding a peak value of the signal, comparing the peak value with a predetermined threshold value, detecting that the former exceeds the latter, and detecting the pinching prevention instruction. The anti-jamming device according to claim 1, further comprising: a comparison / detection circuit that emits a signal. 4. The pinch prevention according to claim 1, wherein at least a part of a surface of the contact body on a side in contact with the movable body is covered with an insulator. apparatus. 5. The anti-jamming device according to claim 1, wherein the contact body includes at least a flexible insulator. 6. A pinching prevention method for preventing a foreign object from being pinched between a movable body that is automatically opened and closed, such as a window glass or a door, and a contact body, such as a frame thereof, and Detecting a capacitance formed between a conductive sensor electrode and a foreign substance installed at a portion of the above; outputting a signal corresponding to the detected capacitance; and A step of detecting whether a foreign object has been caught between the contact body and the movable body, and issuing a pinch prevention command when detecting that the foreign object has been caught. Characteristic pinch prevention method.