JP2009145193A - Cable-like pressure sensitive sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cable-like pressure sensitive sensor having high detection performance and high safety when being inserted. <P>SOLUTION: The sensor includes a flexible and coaxial piezoelectric sensor 4 comprising four layers formed of a center electrode, a piezoelectric material, an outside electrode and a coating layer; and a support part for supporting the outside of the piezoelectric sensor 4. The sensor has a configuration held by the support part with a twisting torque applied in an increasing direction of an elastic modulus of the piezoelectric sensor 4. Hereby, the cable-like pressure sensitive sensor having excellent detection performance and high safety can be provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flexible cable-like pressure sensor.

  2. Description of the Related Art Conventionally, a pinch sensor in which a cable-like pressure sensor is disposed on an end surface of a slide door has been disclosed as a pinch detection sensor for a power slide door of a vehicle (see, for example, Patent Document 1).

FIG. 7 is a cross-sectional view in which a cable-like pressure sensor using a piezoelectric sensor described in Patent Document 1 is mounted on a slide door, where 1 is a cable-like piezoelectric sensor and 2 is an elastic body that holds the piezoelectric sensor 1. The support portion 3 is a sliding door on which the support portion 2 is mounted. In such a configuration, when the sliding body 3 serving as the moving body is closed from the opened state, if the contact body touches the piezoelectric sensor 1 part and pinching occurs, the piezoelectric sensor 1 generates an electrical signal, A determination process is performed on a threshold value set in advance in a signal processing unit (not shown) to which the piezoelectric sensor 1 is connected, and when it is determined that the object is pinched, the sliding door 3 is controlled to perform a reverse operation.
JP 2004-316087 A

  However, in the cable-shaped pressure sensor using the piezoelectric sensor 1, the magnitude of the electric signal generated by the piezoelectric sensor 1 when the contact body is sandwiched is the deflection applied to the piezoelectric sensor 1 together with the sensitivity of the piezoelectric sensor 1 itself. Depends on the speed and the amount of deflection. In other words, the sensitivity performance of the piezoelectric sensor 1 is high, the applied speed is fast, and the electric signal that is generated increases as the range in which the piezoelectric sensor 1 is displaced increases.

  For this reason, for example, when the contact body to be pinched is stationary and closes at a substantially constant speed like a power slide door, the detection signal becomes smaller as the deformation area of the piezoelectric sensor is smaller, and the preset pinching is detected. Since the time to reach the threshold is delayed, there is a disadvantage that the moving distance until the sliding door is reversed and the load to be pressed (reverse load) are increased.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a cable-type pressure sensor excellent in detection performance.

  In order to solve the above-described conventional problems, a cable-like pressure sensor of the present invention includes a coaxial coaxial piezoelectric sensor having four layers of a center electrode, a piezoelectric body, an outer electrode, and a coating layer, and the piezoelectric sensor. And a support portion made of an elastic body. The piezoelectric sensor is held by the support portion in a state in which a twisting torque is applied in a direction to increase the elastic modulus of the piezoelectric sensor. As a result, it is possible to provide a cable-type pressure sensitive sensor having excellent detection performance and high safety.

The cable-shaped pressure-sensitive sensor according to the present invention includes a coaxial piezoelectric sensor having four layers of a central electrode, a piezoelectric body, an outer electrode, and a covering layer, and a flexible coaxial-type piezoelectric sensor, and a support portion made of an elastic body that holds the piezoelectric sensor. And is held on the support portion in a state where torque is applied in a direction to increase the elastic modulus of the piezoelectric sensor. For this reason, the elastic modulus of the piezoelectric sensor is increased, and when a contact object such as a person or an object is sandwiched between the slide doors to which the piezoelectric sensor is attached, the deflection area of the piezoelectric sensor is expanded as compared with a state where no torque is applied to the piezoelectric sensor. By doing so, the electrical signal generated by the piezoelectric sensor increases, the response time from contact to detection is shortened, the slide door can be reversed quickly, and safety can be improved.

  A first invention comprises a flexible coaxial piezoelectric sensor comprising four layers of a central electrode, a piezoelectric body, an outer electrode, and a coating layer, and a support portion made of an elastic body that holds the piezoelectric sensor, The piezoelectric sensor is configured to be held on the support portion in a state where torque is applied in a direction to increase the elastic modulus.

  As a result, the elastic modulus of the piezoelectric sensor increases, and when a contact body such as a person or an object is sandwiched between the slide doors on which the piezoelectric sensor is mounted, the deflection area of the piezoelectric sensor is expanded compared to the state where the torque is not applied. Since the generated electric signal increases, the response time from contact to detection is shortened, the sliding door can be reversed quickly, and safety can be improved.

  2nd invention comprised the piezoelectric sensor of the cable-shaped pressure-sensitive sensor of 1st invention in multiple, and set it as the structure hold | maintained in a support part as a state wound up so that a torque may be applied between each piezoelectric sensor The detection signal is increased by detection by a plurality of piezoelectric sensors to improve the detection performance, and the elastic modulus of the piezoelectric sensor is increased by winding the piezoelectric sensors so as to apply torque to each other and holding them on the support portion. As a result, the deflection region is expanded, and the detection performance at the time of pinching can be further improved.

  According to a third aspect of the present invention, the piezoelectric sensor of the cable-shaped pressure sensor of the first aspect is folded and held by the winding support portion so that torque is applied between the piezoelectric sensors. The detection performance is enhanced by a synergistic effect of the effect that the deflection of two places in the piezoelectric sensor occurs at the same time and the sensitivity increase effect by increasing the elastic modulus of the piezoelectric sensor by winding up the mutual piezoelectric sensors by folding. A cable-like pressure sensor can be provided.

(Embodiment 1)
A cable-like pressure sensitive sensor according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view before the cable-shaped pressure-sensitive sensor is mounted on the indicating unit, and FIG. 2 is a cross-sectional view of the main part in a state where the sensor is mounted on the slide door.

  The piezoelectric sensor 4 includes four layers of a center electrode 4a, a piezoelectric body 4b, an outer electrode 4c, and a covering layer 4e, and is configured in a flexible coaxial cable shape. Connected to the terminal portion of the piezoelectric sensor 4 are a signal processing unit 5 that amplifies, filters, and determines a threshold value of an electric signal generated by the piezoelectric sensor 4, and a control unit 6 that receives the signal and controls the main body. . The piezoelectric sensor 4 is held by a support portion 7 made of an elastic body, and the support portion 7 is provided with a hollow portion 7 a and a fixing portion 7 b for fixing to the distal end portion of the slide door 8. When the piezoelectric sensor 4 is mounted on the support portion 7, a twisting torque is applied in the axial direction of the piezoelectric sensor so that the elastic modulus of the piezoelectric sensor 4 is increased as shown in FIG. 9 is a lead wire for connecting the signal processing unit 5 and the control unit 6, and 10 is a contact body.

  The operation and action of the cable-like pressure sensor configured as described above will be described below.

When the contact body 10 touches the piezoelectric sensor 4 while the sliding door 8 which is a moving body is operating in the closing direction, an electrical signal is generated by the piezoelectric sensor 4, and the electrical signal is required by the signal processing unit 5. Filter processing and amplification processing are performed to extract the signal. When the signal exceeds a preset threshold value, a pinch detection signal is sent from the signal processing unit 5 to the control unit 6 and the slide door 8 is reversed.

  FIGS. 3A and 3B show the case where the twisting torque is not applied to the piezoelectric sensor 4 (A) and the case where the torque is applied (B), and shows the difference in the bending state of the piezoelectric sensor 4 when the piezoelectric sensor 4 sandwiches the contact body 10. The bending elastic modulus is increased by applying a twisting torque to the piezoelectric sensor 4, and the deflection range C2 of the piezoelectric sensor 4 becomes larger than C1. FIG. 4 shows an output signal generated by the piezoelectric sensor 4 in accordance with the state of FIG. 3 and a pinching detection output signal signal-processed by the signal processing unit 5 based on the electric signal, and S1 applies a twisting torque. When there is no piezoelectric sensor output signal, S2 is a piezoelectric sensor output signal with a twist torque applied, and L1 and L2 are pinching detection threshold values set in the signal processing unit 5 in advance.

  When the contact body 10 comes into contact with the piezoelectric sensor 4 part, the S1 and S2 signals are output from the piezoelectric sensor 4, and when the threshold value L1 is exceeded, the pin detection signal P1 or P2 is sent from the signal processing part 5 to the control part 6 Then, the slide door 8 is reversed. T1 and T2 indicate the response time from when the contact body 10 touches the piezoelectric sensor 4 and the signals S1 and S2 are output until the pinching detection signal P1 and P2 is output. Since the threshold value is quickly reached, the response time T2 is accelerated, and the load (reversal load) applied to the contact body 10 before the sliding door 8 is reversed can be reduced, and the usability and safety can be improved.

(Embodiment 2)
A cable-like pressure sensor according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a side view of the piezoelectric sensor portion of the cable-like pressure sensor, and FIG. 6 is a cross-sectional view of the main part of the cable-like pressure sensor. In addition, about the structure similar to Embodiment 1, the same symbol is attached | subjected and description is abbreviate | omitted.

  The cable-shaped pressure-sensitive sensor of the second embodiment uses two piezoelectric sensors 11 and 12 having the same shape, and the piezoelectric sensors 11 and 12 are wound up so as to apply torque to each other and held on the support unit 13. The terminals of the plurality of sensors 4 are connected to the same signal processing unit 14. By configuring in this way, the detection signal when the contact object is sandwiched is detected by two sensors, and the piezoelectric sensors 11 and 12 are elasticized by applying torque and holding them in the winding instruction unit 13. Increasing the rate improves detection performance and enables highly safe pinching detection.

  In this embodiment, two piezoelectric sensors are used. However, if necessary, the detection sensitivity can be further increased by increasing the number of piezoelectric sensors.

(Embodiment 3)
A cable-like pressure sensor according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a side view of the piezoelectric sensor portion of the cable-like pressure sensor, and FIG. 8 is a cross-sectional view of the main part of the cable-like pressure sensor. In addition, about the structure similar to Embodiment 1, the same symbol is attached | subjected and description is abbreviate | omitted.

  In the cable-shaped pressure sensor of the third embodiment, the piezoelectric sensor 15 is folded and held on the winding support 16 so as to apply torque to the piezoelectric sensors 15a and 15b.

  With this configuration, when the piezoelectric sensors 15a and 15b come into contact with the contact body, even if a single piezoelectric sensor is bent, bending occurs at two places, and the piezoelectric sensors 15a and 15b further. By winding up so that torque is applied to each other and holding it on the support portion 16, the synergistic effect of increasing the sensitivity due to the increase in the elastic modulus of the piezoelectric sensor enables excellent detection performance with a simple configuration using a single piezoelectric sensor. Highly safe pinching detection is possible.

  As described above, the cable-shaped pressure sensor according to the present invention can provide a cable-shaped pressure sensor with improved detection performance and safety when the contact body is sandwiched, so that the sliding door of an automobile can be provided. It can be widely used as a pinch detection sensor for residential doors and other doors as well as for applications.

FIG. 3 is a perspective view of the cable-shaped pressure sensor according to Embodiment 1 of the present invention before mounting on the indication unit Sectional drawing of the principal part of the cable-shaped pressure-sensitive sensor in Embodiment 1 of this invention Sectional drawing which shows the principal part which shows the clamping state of the cable-shaped pressure sensor in Embodiment 1 of this invention The characteristic view which shows the output signal at the time of pinching of the cable-shaped pressure-sensitive sensor in Embodiment 1 of this invention Side view of the cable-shaped pressure sensitive sensor according to the second embodiment of the present invention. Sectional drawing of the principal part of the cable-shaped pressure-sensitive sensor in Embodiment 2 of this invention. Side view of a cable-shaped pressure sensitive sensor according to Embodiment 3 of the present invention. Sectional drawing of the principal part of the cable-shaped pressure-sensitive sensor in Embodiment 3 of this invention. Cross section of the main part of a conventional cable-type pressure sensor

Explanation of symbols

4 Piezoelectric sensor 4a Center electrode 4b Piezoelectric body 4c Outer electrode 4d Coating layer 7 Pointer

Claims (3)

The pressure sensor is provided with a flexible coaxial piezoelectric sensor including a central electrode, a piezoelectric body, an outer electrode, and a coating layer, and a support portion that holds the outside of the piezoelectric sensor. A cable-shaped pressure-sensitive sensor configured to be held by the supporting portion in a state where a twisting torque is applied in the increasing direction. The cable-shaped pressure-sensitive sensor according to claim 1, wherein a plurality of piezoelectric sensors having the same shape are used, and the piezoelectric sensors are held on the support in a state where the piezoelectric sensors are wound up so as to apply torque. The cable-shaped pressure sensor according to claim 1, wherein the piezoelectric sensor is folded and held on the support portion in a state where the piezoelectric sensors are wound up so that torque is applied between the piezoelectric sensors.