JPH07286477A - Nipping detecting device and nipping preventing device in opening and closing mechanism - Google Patents

Abstract

PURPOSE:To prevent erroneous detection or erroneous operation, and realize a more precise nipping detection by increasing a resistance, when the opening and closing part of an opening and closing mechanism nips something, lowering the speed of a motor to increase the pulse interval, detecting this by a comparison part, and outputting a signal by a nipping detecting part. CONSTITUTION:Normal rotation, reverse rotation and stopping of a motor M are switched by a motor control part 14. The rotating angle of the motor M is detected as pulse, which is then counted to detect the position of a windowpane 2. When something is nipped between its upper end 2a and the upper part 1a of a door sash 1, a signal such as stop signal is transmitted from a detecting part 15 to the motor control part 14. The abnormality between the window glass 2 and the door sash 1 is judged from the fluctuation of the pulse interval, and an avoiding operation is instructed from a nipping detecting part 16 to the motor control part 14. When the motor rotating speed is raised, thus, the erroneous detection for erroneously generating the nipping signal is minimized to prevent the erroneous operation, and a precise nipping detection can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an entrapment detection device for an opening / closing mechanism, an entrapment prevention device using the same, and an opening / closing device using the same. For more details,
In an opening / closing mechanism driven by a motor, such as a power window of an automobile, when a person's hand or the like is accidentally pinched, a detection device that detects the accident, and the opening / closing mechanism is immediately opened on the safe side. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a trapping prevention device that can be operated in the above manner, and an opening / closing mechanism including the trapping prevention device.

[0002]

2. Description of the Related Art Conventionally, there has been known a power window device for opening and closing an opening of a window in a door window of a vehicle, a sunroof which can be opened and closed by sliding, and a window glass is reciprocally moved by driving a motor. In this type of power window device, an accident may occur in which the passenger's hand or the like is mistakenly caught between the window glass and the window frame during the closing operation. From the viewpoint of preventing an injury due to such entrapment, conventionally, an entrapment prevention device that detects the entrapment at an early stage and promptly stops or reverses the wind glass has been proposed. For example, the actual exploitation 62
In Japanese Patent Laid-Open No. 193082, a pulsating current (ripple) of a driving motor is taken out as a pulse, and a pulse interval is measured to detect a rotation speed and a rotation speed fluctuation rate of the motor, and a comparison process with a reference value is performed. It has been proposed to provide a device for detecting entrapment and an automatic window glass lifting device for an automobile that includes a control unit that stops the motor after moving the window glass in the opening direction by a predetermined width based on the detection of entrapment.

[0003]

Since the window glass for opening and closing the window is usually guided by the door sash, the sliding resistance with the sash cannot be ignored. Furthermore, mechanical resistance also exists in the mechanical parts such as the window regulator. Moreover, such sash resistance and mechanical resistance change greatly depending on the position of the windshield and environmental changes such as temperature,
This is a major cause of fluctuations in the rotation speed of the drive motor, and eventually in the pulse interval from the motor.

However, in the above-mentioned conventional lifting device, the interval of the pulse coming out of the drive motor is detected as an absolute value, and the pulse interval is directly compared with a specific reference value, or the fluctuation rate of the pulse interval is changed. Is calculated and compared with the reference value. Therefore, even if the pulse interval is temporarily increased due to an increase in sash resistance or mechanical resistance during the closing operation, the operation of the drive unit is stopped by the incorrect judgment of the control unit, or the operation shifts to the opening operation. However, there is a problem in that the reliability and reliability of entrapment detection may not be sufficient.

SUMMARY OF THE INVENTION An object of the present invention is to prevent malfunction in a motor-driven switchgear such as a window regulator due to the influence of mechanical resistance and the environment and to improve the stability and reliability of pinch detection.

[0006]

A pinch detection device according to the present invention is a pinch detection device in an opening / closing mechanism that is reciprocally driven by a motor, and rotates when the motor rotates at least in a direction to close the opening / closing mechanism. Means for generating a pulse according to the angle, means for sequentially detecting the pulse intervals of the generated pulse train, means for calculating an average value of a predetermined number of pulse intervals, and calculation of a reference value based on the average value Means for sequentially comparing the reference value with a newly detected pulse interval, and when the pulse interval exceeds the reference value, means for outputting an abnormality detection signal, and a detection signal based on the abnormality detection signal. It is characterized by comprising means for outputting.

In such an apparatus, the means for calculating the average value has means for counting the generated pulses and means for storing at least a predetermined number of the detected pulse intervals, When the number of counts reaches a predetermined number, the average value may be calculated based on the stored predetermined number of pulse intervals. In that case, the reference value is stored until the reference value is updated next time, and the reference value is compared with the pulse interval. Further, the counting means newly starts counting, and the storing means newly stores the pulse intervals in sequence.

The means for calculating the average value include means for counting the pulses, means for sequentially adding the detected pulse intervals and storing the added result, and the count number of the counting means reaches a predetermined number. At this time, the sum of the added pulse intervals may be divided by the predetermined number to obtain the average value. In this case also, the means for calculating the reference value calculates a new reference value based on the calculated average value and stores it in the reference value storage means. Further, the counting means newly starts counting pulses, and the storage means newly starts adding pulse intervals.

Further, as means for calculating the average value,
Consists of means for storing a predetermined number of detected pulse intervals, means for updating the memory of the oldest pulse interval to a newly detected pulse interval, and means for calculating the average value of the stored pulse intervals. You can also do it.

The reference value can be determined by multiplying the average value of the pulse intervals by a constant coefficient. Further, the coefficient may be changed according to the position of the opening / closing mechanism. Furthermore, the means for outputting the entrapment detection signal is for outputting the entrapment detection signal for the first time when the pulse interval exceeds the reference value and the next detected pulse interval further exceeds the pulse interval. Is preferred.

The entrapment prevention device of the present invention comprises any one of the entrapment detection devices described above, and means for stopping the motor or rotating the motor in the opening direction when the entrapment detection signal is output from the detection device. . An opening / closing device of the present invention includes a motor, an opening / closing mechanism that is driven to open / close by the motor, and the pinch prevention device provided in the motor and a control unit thereof.

[0012]

In the pinching detection device of the present invention, when an object is caught in the opening / closing part of the opening / closing mechanism and resistance increases, the rotation speed of the motor decreases and the pulse interval generated by the pulse generating means increases. Therefore, the pulse interval detected by the pulse interval detecting means exceeds the reference value. This is detected by the comparison means, and the pinch detection signal is output based on it. The reference value in that case is not fixed, but is determined based on the average value of a plurality of past pulse intervals. Therefore, if the frictional resistance of the mechanical part of the opening / closing mechanism or the sliding resistance between the window glass and the window sash fluctuates due to changes in the environment, etc. Will be compared with. That is, when the temperature decreases and the sliding friction resistance increases, the reference value increases accordingly, and conversely, when the temperature increases and the friction resistance decreases, the reference value decreases. Therefore, erroneous detection and erroneous operation caused by the change in frictional resistance due to such environmental changes are prevented.

As means for calculating the average value, means for storing a predetermined number of pulse intervals, means for calculating the average value based on the stored pulse intervals, and means for storing the calculated reference value. When and are adopted, the number (capacity) of the storage means can be reduced. Furthermore, since the average value can be calculated in parallel with pulse detection,
The operation speed is fast. On the other hand, as a means of calculating the average value,
A means for counting the pulses, a means for sequentially adding the detected pulse intervals, a means for storing the added results, and a sum of the added pulse intervals when the count number of the counting means reaches a predetermined number. When configured by means for dividing by a number to obtain an average value, the number of storage means (capacity) can be further reduced because the means for storing the pulse interval need only be the means for storing the sum.

Further, means for calculating an average value of the pulse intervals, means for storing a detected predetermined number of pulse intervals,
When the means for updating the memory of the oldest pulse interval to the newly detected pulse interval and the means for calculating the average value of the stored pulse intervals, it is always necessary to compare with the newest average value. Therefore, it is possible to more reliably prevent erroneous detection.

When calculating the reference value from the average value of the pulse intervals, the number of samples of the pulse interval and the safety factor are set to
By setting an appropriate coefficient and multiplying the coefficient by the average value to obtain the reference value, the reference value can be easily calculated. However, the coefficient may be changed according to the position of the opening / closing mechanism. Further, in any of the above cases, the sandwiching signal can be issued immediately when the detected pulse interval exceeds the reference value, but it is stored that one pulse interval exceeds the reference value. Further, if the sandwiching signal is output only when the pulse interval immediately after is longer than the pulse interval before, the erroneous detection can be further prevented. If it is not increasing, try to clear the memory.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An entrapment detection device, an entrapment prevention device, and a motor-driven opening / closing device of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a control circuit for an opening / closing mechanism equipped with a pinch prevention device of the present invention,
FIG. 2 is a schematic configuration diagram showing an embodiment of an opening / closing mechanism to which the entrapment prevention device is applied, and FIGS. 3 and 4 are block diagrams showing the essential parts of an embodiment of the entrapment detection device of the present invention and their operation. FIG. 5 is a graph for explaining the operation of the entrapment detection device of the present invention over time, and FIGS. 6 and 7 are block diagrams showing the essential parts of another embodiment of the entrapment detection device of the present invention. .

First, an example of an opening / closing mechanism to which the present invention is applied will be described with reference to FIG. Reference numeral 1 in FIG. 2 is a door sash of an automobile, and a window glass 2 that moves up and down in the door sash 1 is driven up and down by a window regulator 3 that is an opening / closing mechanism. Window regulator 3
Is a carrier plate 4 fixed to the lower end of the window glass 2, a guide rail 5 attached to a door panel to guide the vertical movement of the carrier plate 4, and guide pulleys rotatably provided at the upper and lower ends of the guide rail 5. A driven portion 8 made up of 6 and 7, a cable drum 9 rotatably provided on the door panel, a drive portion 10 made up of a motor M for rotatably driving the cable drum 9 via a speed reducer, and a cable 11 connecting the two. It consists of and. A part of the cable 11 is locked to the carrier plate 4, is turned around by the guide pulleys 6 and 7, and is locked to the cable drum 9 and wound.

Therefore, in this device, when the motor M rotates in one direction to rotate the cable drum 9 in the direction of arrow A, the loop of the cable 11 is circulated in the direction of arrow A1,
Raise the window glass 2. When the motor M rotates in the opposite direction to rotate the cable drum 9 in the direction of arrow B, the window glass 2 descends. The entrapment detection device of the present invention, in the opening / closing mechanism having such a configuration, is provided between the upper end 2a and the upper part 1a of the door sash 1 when closing the window glass 2, that is, when raising the window glass 2 in the case of FIG. If a person's hand or the like is accidentally pinched in, the pinch prevention device immediately detects when pinch is detected.
By reversing, the window glass 2 is lowered to some extent and stopped, and the like, so as to cope with safety.

FIG. 1 shows an embodiment of a control circuit for such an opening / closing mechanism. The opening / closing mechanism control circuit 13 includes a motor control unit 14 for switching between forward rotation, reverse rotation and stop of the motor M described above. , The rotation angle of the motor M is detected as a pulse, the pulse is counted, the position of the window glass 2 is detected, and a detection unit 15 that sends a stop signal or the like to the motor control unit 14 and a window from the fluctuation of the pulse interval. A pinch detection unit 16 that determines that an object is pinched between the glass 2 and the sash 1 and instructs the motor control unit 14 to perform an avoidance operation.
It consists of and.

The motor control unit 14 includes a pair of relays R1 and R2 interposed between the motor M and the DC power source S and the ground G to switch between normal rotation, reverse rotation and stop of the motor M, and their relays. A relay driver 17 that sends a switching drive signal to the relays R1 and R2, a control circuit 18 that sends a digital signal for control to the relay driver 17, and an operation signal for opening and closing and stopping the window by the operator to the control circuit 18. Operation unit 19 equipped with a switch
It consists of and. When the opening and closing of the window is operated by such a motor control unit 14, a switch of the operation unit 19 is operated, thereby switching the relays R1 and R2 via the control circuit 18 and the relay driver 17, thereby rotating the motor M. Controls stop and forward / reverse rotation.

The detection unit 15 is connected in parallel to the drive wire of the motor M and generates a number of pulses proportional to the rotation angle of the motor M. The sampling unit 21 continuously generates the pulses. And a position detection unit 22 for obtaining information on the rotation angle of the motor M, and by extension, the position of the windshield 2. The sampling unit 4 is the pulse generating means according to the first aspect, and can be configured by, for example, a waveform shaping circuit using a comparator that forms a pulse waveform from the pulsating current (ripple) of the motor M. The pulse generating means can also be configured by a pulse generator such as a perforated disk and a microphotosensor attached to the rotating shaft of the motor M, or a magnet and a hall element attached to the rotating shaft. The position detector 22
A counter for counting the pulses output from the sampling unit 21 is provided, and the signal of the opening / closing position of the window glass 2 which is obtained according to the count number is the control circuit 18.
To be sent to. As a result, it is detected that the rising edge and the falling edge of the window glass 2 in FIG. 2 have been reached, and the control circuit 18 sends signals to the relay driver 17 to stop the motor M, respectively. The counter may be cleared to zero each time the window glass 2 reaches the rising end, for example.

The entrapment detecting section 16 includes a pulse interval detecting section 23 for sequentially detecting the intervals of pulse trains output from the sampling section 15 as numerical data, and an average value calculation for calculating an average value of a predetermined number of these pulse intervals. A calculation unit 26 including a unit 24 and a reference value calculation unit 25 that calculates a reference value based on the average value thereof, and the calculation unit 26.
A comparison unit 27 which compares the reference value output from the pulse interval data with the pulse interval data sent from the pulse interval detection unit 23 to determine the magnitude, and a control circuit for the motor reverse rotation signal and the stop signal based on the comparison result. It is composed of a judgment unit 28 which sends the data to the unit 18. The pulse interval detector 23 is
This is a part that compares the intervals of pulse trains that are sequentially transmitted with a clock pulse or the like and converts them into numerical data one after another, and can be configured by a timer / counter circuit or the like. When the pulse is generated based on the pulsation of the motor, the pulse interval is the same as the pulse width, so the pulse width may be detected.

Next, referring to FIG. 3, the trapping detection unit 16
A specific example of the essential part of the above will be described. The average value calculator 24 in the entrapment detector 16 shown in FIG. 3 uses the data T1, T2, ... Ti, ... Tn of n pulse intervals sequentially sent from the pulse interval detector 23. From the register 29 for storing, the counter 30 that counts the number of pulses sent from the sampling unit 21 from 1 to n, outputs a count-up signal, and then starts counting from 1 again, and the counter 30 Signal to obtain the total sum of n pieces of data in the register 29, further divide by the number of pieces of data n to calculate an average value Tav, and send it to the reference value calculation unit 25. There is.

The reference value calculating section 25 multiplies the data received from the processing element 31 by a coefficient k. The number n of the pulse interval data T and the coefficient k of the reference value calculation unit are selected according to the friction coefficient between the window glass and the door sash, environmental conditions such as temperature, and conditions such as the resistance of the mechanical unit, but are usually selected. The number of data n is 5-10,
Preferably 10 to 20, more preferably 20 to 30
The number of pieces is about 1, and the coefficient k is usually 1.1 to 1.3, preferably about 1.15 to 1.2. Further, the comparison unit 27 obtains the obtained reference value k · Tav and the pulse interval data Ti (i = i = a) newly sent from the pulse interval detection unit 23.
1, 2, ..., N) are sequentially compared, and when the pulse interval data Ti is larger, the determination unit 28 is notified of the data Ti.
Is to be sent. When the reference value is equal to or larger than the reference value, the data Ti is not sent. Judgment unit 28
When the data Ti of the pulse interval is sent from the comparison unit 27, the data Ti is stored, and when the data T (i + 1) of the next pulse interval is continuously sent, the previous pulse Compared with the interval data Ti, the new pulse data interval T (i + 1) is the previous pulse interval T
When it is larger than i, it is determined that the window glass has pinched an object, and a pinching signal is sent to the control circuit (18 in FIG. 1). Even if the first data Ti is sent, the following data T (i + 1) is the first data T
When it is smaller than i, no pinching signal is sent to the control circuit 18. The average value calculation unit 24, the comparison unit 27, and the determination unit 28 are a random access memory (RAM) that temporarily stores data, a read-only memory (ROM) that stores a data processing procedure, and processing of those data. It can be realized by a system composed of a microprocessor or the like for performing.

Next, the operation of the entrapment detection unit 16 of FIG. 3 will be described with reference to FIG. When the entrapment detection unit 16 starts the detection process (step I in FIG. 4), first, the pulse interval data generated by the sampling unit 21 and the pulse interval detection unit 23 is sequentially sent to the register 29, and the detection process is performed. At the same time as step (II), the counter 30 counts the number of pulses. And the count number is n
When reaching +1, the average value Tav = ΣTi / n of the data of n pulse intervals is calculated by the processing element 31 (step III), and based on the average value Tav,
The reference value k · Tav is calculated by the reference value calculation unit 25 (step IV). Then, when the (n + 2) th pulse is detected,
The first memory data T1 of the register 29 is rewritten with the data T (n + 1) of the pulse interval, and n + 1
The nth data (interval between the (n + 1) th pulse and the (n + 2) th pulse) and the n + 2th data (interval between the (n + 2) th pulse and the (n + 3) th pulse) are detected and stored (step V , Step VI). Then, the n + 1-th data and the calculated reference value k · Tav are compared, and the n + 1-th data and the n + 2-th data are compared (step VII). The entrapment detection signal is sent to the control circuit 18 (step VIII). During that time, the standard value k · T
av is constant. The data of the n + 1th, n + 2nd, n + 3rd, etc. are sequentially rewritten to the data of the register 29 and used for the calculation of the next reference value after the 2nth data is entered. To be done. That is, the reference value is rewritten to a new reference value every n pulses.

Next, the actual operating state of the trapping detection will be described with reference to FIG. In FIG. 5, the horizontal axis is the number of generated pulses n (pieces), and the vertical axis is the data T (msec) of the interval of each pulse. The curve Ti shows the variation of the pulse intervals. In the case of the embodiment shown in FIG. 5, the resistance of the driving torque of the motor is large in the O section of the pulse n at the time of rising, so the operation is continued without comparing with the reference value. Then, in the next section of n pulses (section A), the reference value k · Tav1 registered in advance or stored in the previous operation and the data of the pulse width which is sequentially detected are compared with the next one. Go. In the case of FIG. 5, since any detected pulse interval is less than the reference value k · Tav1, no pinch detection signal is generated and the opening / closing mechanism is not inverted.

When the section A ends, the average value Tav1 is calculated based on the pulse interval data stored in the section A, and a new reference value k · Tav1 is calculated. Then, in the next section B, the reference value k · Tav
1 is compared with the pulse intervals that are sequentially detected. In the case of FIG. 5, the detected pulse interval is the original reference value k.
It exceeds To from the middle, but the new reference value k · Tav
The pinch detection signal is not output because it does not exceed 1. When the section B ends, the next new reference value k · Tav2 is calculated based on the average value Tav2 of the new pulse intervals rewritten during the section B. The reference value k · Tav2 is larger than the reference value k · Tav1 in the B section because the pulse interval data in the B section is larger than that in the A section.

Then, the C section is detected based on the obtained reference value k · Tav2. In section C, the reference value k.multidot.Tav2 that has been increased as described above is compared with the pulse interval. Therefore, when the pulse interval gradually increases, the pinch signal is not output. However, as shown in FIG. 5, when the data Ti of a certain pulse interval rapidly increases and exceeds the reference value k · Tav2, and the next pulse interval T (i + 1) exceeds the pulse interval Ti,
It is considered that the entrapment has occurred in the opening / closing mechanism, and an entrapment detection signal is generated and sent to the control circuit 18. Thereby, the reversing operation of the motor M is performed through the relay driver 17 and the relays R1 and R2, and the descending operation is started. In this way, entrapment is immediately detected and a major accident can be prevented in advance. Note that the symbol F in FIG.
Is an absolute inversion start reference value for immediately performing the inversion operation when the pulse interval exceeds this level regardless of the reference value.

In the above embodiment, the reference value is obtained by multiplying the average value of the pulse intervals by a certain coefficient k, but it may be used as the reference value by adding a constant to the average value.
Furthermore, an appropriate relational expression may be determined by analyzing experimental data. Further, in the above-described embodiment, when the pulse interval data exceeds the reference value only once, the sandwiching signal is not output, and the sandwiching signal is continuously exceeded twice, and when the second time is larger than the first time, that is, the sequential pulse interval. Is increasing (when the motor rotation is slowing down)
As long as the interposition signal is output, the interposition signal may be output when the data for the third time or after that exceeds the data immediately before,
On the contrary, it is also possible to output the pinching signal immediately when the reference value is exceeded only once. In the latter case, the possibility of erroneous detection is high, but there is an advantage that the sandwiching signal is issued quickly.

Next, another embodiment of the average value calculator will be described with reference to FIG. Although the register 29 having the same number of storage addresses as the number of detected pulses is adopted in the embodiment of FIG. 3, the average value calculating section 24 shown in FIG. 6 has only one storage address of the register 29. The contents of the register 29 are rewritten to the total sum of the detected pulse intervals sequentially added. Then, when n pulses are detected, the average value ΣT is calculated from the sum ΣTi of the pulse intervals.
Calculate i / n. In this way, the storage capacity of the register can be reduced and the calculation time can be shortened.

The average value calculation unit 24 shown in FIG. 7 always stores data of n pulse intervals, but each time new data comes in, the oldest data is rewritten to the new data, and these new data groups are rewritten. The reference value is calculated one after another based on. Since the reference value of this device is constantly updated, there is an advantage that erroneous detection and malfunction are further reduced. Also, no counter is required.
The average value may be calculated each time by obtaining the total sum and dividing by n, but the original average value data ΣT / s (s = i, ..., i + n) ) / N plus the variation, that is, the difference [T (i + n) -Ti] between the oldest data and the data to be newly updated divided by n, and then ΣTs / n- {Ti-T (i + n) } /
By obtaining n, a new average value ΣTi (i = 2,
It is preferable to calculate ... N + 1) / n.

[0032]

According to the entrapment detection device of the present invention,
Since the reference value for determining whether or not an object is sandwiched changes, so to speak, with the average value of the immediately preceding history, it changes following the natural changes in the environment and friction resistance. Therefore, when the number of rotations of the motor increases due to frictional resistance or the like, there is little erroneous detection that erroneously generates the pinch signal, and erroneous operation can be prevented. Therefore, it is not necessary to set the reference value to a large value as in the conventional case, and it is possible to accurately detect the entrapment.

Since the entrapment prevention device and the opening / closing mechanism of the present invention employ the entrapment detection device, when the entrapment occurs, the avoidance operation can be swiftly and surely performed, and the safe opening / closing operation can be performed. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a control circuit for an opening / closing mechanism provided with a pinch prevention device of the present invention.

FIG. 2 is a schematic configuration diagram showing an embodiment of an opening / closing mechanism to which the pinch prevention device of FIG. 1 is applied.

FIG. 3 is a block diagram showing a main part of an embodiment of the entrapment detection device of the present invention.

FIG. 4 is a flowchart showing an operation of the trapping prevention device of FIG.

FIG. 5 is a graph for explaining the action of the entrapment detection device of the present invention over time.

FIG. 6 is a block diagram showing a main part of another embodiment of the entrapment detection device of the present invention.

FIG. 7 is a block diagram showing a main part of still another embodiment of the entrapment detection device of the present invention.

[Explanation of symbols]

 3 Wind Regulator 13 Control Circuit for Opening / Closing Mechanism 16 Entrapment Detection Section 18 Control Circuit 21 Sampling Section 23 Pulse Interval Detection Section 24 Average Value Calculation Section 25 Reference Value Calculation Section 27 Comparison Section 28 Judgment Section 29 Register 30 Counter

Claims (8)

[Claims] 1. A pinch detection device in an opening / closing mechanism which is reciprocally driven by a motor, wherein a means for generating a pulse in accordance with a rotation angle when the motor rotates at least in a direction of closing the opening / closing mechanism, Means for sequentially detecting the pulse intervals of the coming pulse train, means for calculating an average value of a predetermined number of pulse intervals, means for calculating a reference value based on the average value, and the reference value newly detected. The pinch detection device in the opening / closing mechanism, which comprises means for sequentially comparing the pulse intervals with each other and outputting a pinch detection signal when the pulse intervals exceed the reference value. 2. The means for calculating the average value has a means for counting the generated pulses and a means for storing at least a predetermined number of the detected pulse intervals, and the count number of the pulses is a predetermined number. Is to calculate the average value of the stored pulse intervals, the means for calculating the reference value has a means for storing the reference value,
While calculating a new reference value based on the average value,
The apparatus according to claim 1, wherein the calculated reference value is stored in the storage means, and the counting means starts a new count of pulses and the pulse interval storage means starts a new storage of pulse intervals. 3. The means for calculating the average value includes means for counting pulses and means for sequentially adding detected pulse intervals and storing the added result, and calculates the reference value. Means for storing the reference value, and when the count number of the counting means reaches a predetermined number, the sum of the added pulse intervals is divided by the predetermined number to obtain an average value. 2. A reference value is calculated on the basis of the calculated value and stored in the reference value storage means, and the counting means starts counting new pulses and the pulse interval storage means starts storing new pulse intervals.
The described device. 4. A means for calculating the average value, a means for storing a predetermined number of detected pulse intervals, a means for updating the memory of the oldest pulse interval to a newly detected pulse interval, and a pulse interval. And means for calculating an average value of the pulse intervals stored each time a pulse is detected.
The described device. 5. The apparatus according to claim 1, wherein the means for calculating the reference value is a reference value by multiplying the average value of the pulse intervals by a constant coefficient. 6. The means for outputting the entrapment detection signal, when the pulse interval exceeds a reference value and the next detected pulse interval exceeds the pulse interval,
A pinch detection signal is output for the first time.
4. The device according to 4 or 5. 7. A detection device according to claim 1, 2, 3, 4, 5 or 6, and means for stopping the motor or rotating the motor in the opening direction when a pinch detection signal is output from the detection device. Entrapment prevention device consisting of. 8. A motor-driven opening / closing device including a motor, an opening / closing mechanism that is driven to open / close by the motor, and a pinch prevention device according to claim 7, which is provided in a control unit of the motor.