JP4702413B2 - Proximity sensor - Google Patents

Description

  The present invention relates to a proximity sensor.

2. Description of the Related Art Conventionally, there is a sensor that detects the approach of a detection object such as a metal and outputs an electric signal by reversing the contact points when the detection object presses a shaft.
(For example, see Patent Document 1)
JP-A-6-162870

  The sensor in the above-described conventional example is a so-called contact type sensor in which the detection object presses the shaft so that the contacts are connected, and the sensor outputs a detection signal, and the detection target has a large force to press the shaft. For this reason, a large impact has occurred on the sensor.

  In addition, since each part is configured separately, when installing a sensor with each part assembled, variation occurs in the mounting accuracy of the shaft that detects the object to be detected, which in turn causes variation in detection accuracy. There was a problem to do.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a proximity sensor with high detection accuracy without an impact being transmitted to the sensor.

According to the first aspect of the present invention, a coil bobbin around which a coil is wound, a high-frequency electromagnetic field is generated in the coil, and a detection signal corresponding to a change in the high-frequency electromagnetic field due to the approach of a detection target to the coil is generated. A control circuit; an input / output connector that outputs a detection signal of the control circuit and supplies power to the control circuit; a body to which the control circuit and the input / output connector are attached; and a cylindrical cover that houses the coil bobbin. The coil bobbin and the body are integrally molded , and a gap between the cover and the tip of the coil bobbin is filled with a sealing material .

According to this invention, the approach of the detection target can be detected in a non-contact manner, and the assembly accuracy of the coil bobbin can be improved, so that the impact is not transmitted to the sensor and the detection accuracy can be improved. . In addition, while the coil is disposed at the tip of the sensor, the seal structure of the tip can be easily configured with few parts.

According to a second aspect of the present invention, in the first aspect of the invention, a cylindrical housing that is attached to the body and houses the control circuit is provided, and the opening peripheral edge of the housing located on the coil bobbin side with respect to the control circuit and the body to form a gap, one end of the cover is inserted into the gap, wherein the sealing material is filled in the gap.

  According to the present invention, the gap between the body and the housing can be sealed, and the cover can be fixed to the body.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the coil bobbin has a core integrally formed.

  According to the present invention, it is possible to save the time and labor for assembling the core to the coil bobbin, and in addition, the accuracy of the position where the core is fixed is improved and the detection accuracy can be improved.

  As described above, according to the present invention, there is an effect that an impact is not transmitted to the sensor and a proximity sensor with high detection accuracy can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
The proximity sensor in this embodiment is demonstrated using FIGS. Note that a direction orthogonal to the up / down / left / right direction is defined as the front / rear direction with reference to the up / down / left / right direction in FIG.

  As shown in FIG. 1, the proximity sensor according to the present embodiment supplies a power to the body 1 integrally formed with the coil bobbin 2, a control board 3 attached to the body 1, a power supply to the control board 3, and outputs a detection signal. Input / output connector 4, housing 10 that is attached to body 1 and accommodates control board 3, and cylindrical cover 15 that accommodates coil bobbin 2 (see FIGS. 1 to 4).

  First, the body 1 includes a coil bobbin 2 formed in an approximately cylindrical shape from an insulating material such as a resin, a rectangular plate-shaped substrate mounting portion 5 extending upward from the upper end of the coil bobbin 2, and a substrate mounting portion. 5 is composed of a disc-shaped flange portion 6 formed at the upper end of 5 and a plug fitting portion 7 formed on the upper surface of the flange portion 6 (see FIGS. 5A to 5E and FIG. 6).

  The coil bobbin 2 is formed in a substantially cylindrical shape, and is formed with a cylindrical hole portion (not shown) from the substantially lower center of the coil bobbin 2 toward the inside, and a cylindrical core 8 made of ferrite or the like is formed in the hole portion. Is stored. And the groove part 2a is formed in the circumferential direction in the outer peripheral surface of the coil bobbin 2 vicinity of the lower end, and the coil 9 is wound by the said groove part 2a.

  The board attachment portion 5 is formed on a rectangular flat plate and is provided behind the center of the upper surface of the coil bobbin 2, and a collar portion 6 formed in a substantially disc shape is provided at the upper end of the board attachment portion 5. On the upper surface of the flange portion 6, a plug fitting portion 7 having an open upper surface and formed in a bottomed cylindrical shape is provided.

  Next, the control board 3 is disposed on the front surface side of the board mounting portion 5 and is supported and fixed by screwing or the like to spacers 11 provided at the left and right ends of the board mounting portion 5 in the substantially vertical direction. 12 and three input / output connectors 4 are connected (see FIGS. 7A and 7B).

  The coil terminal 12 is provided at the rear upper end of the coil bobbin 2, and the terminal portion 12a to which the end portions of the coil 9 are respectively connected by lapping, and is extended upward from the tip of the terminal portion 12a to be connected to the substrate mounting portion 5. An extending portion 12b that extends downward into the insertion hole 5b that is formed in the front-rear direction, and a through (not shown) that extends forward from the tip of the extending portion 12b and is formed in the lower portion of the control board 3. It is comprised from the connection part 12c connected with the control board 3 by solder after inserting a hole.

  The input / output connector 4 includes three terminals, ie, a power supply terminal, a detection signal output terminal, and a common terminal, and is substantially at the center of the bottom surface 7b of the plug insertion hole 7a formed in the plug fitting portion 7 in a substantially cylindrical shape. To the insertion hole 5a formed in the upper part of the board attaching part 5 through the flange part 6 and the terminal part 4a formed from the lower end of the terminal part 4a toward the front and on the upper part of the control board 3. It is formed in a substantially L shape from the connecting portion 4b connected to the control substrate 3 by soldering after inserting a through hole (not shown) to be formed. The terminal portion 4a protrudes from the bottom surface 7b into the plug insertion hole 7a.

  Then, when a plug (not shown) is inserted and connected to the plug fitting portion 7, power is supplied to the proximity sensor and a detection signal is output to the outside.

  The housing 10 is formed of a metal material such as S45C, and includes a hexagonal column portion 10A and a cylindrical portion 10B formed below the hexagonal column portion 10A. The control board 3 is provided inside the hexagonal column portion 10A and the cylindrical portion 10B. Is formed with a cylindrical opening 13. A cylindrical portion 10C is formed on the upper surface of the hexagonal column portion 10A, and is further locked to the upper surface of the flange portion 6 of the body 1 at equal intervals in the circumferential direction from the opening peripheral edge of the cylindrical portion 10C. A locking claw portion 10a is formed. Further, a groove 6a is formed on the outer peripheral surface of the flange portion 6 that contacts the cylindrical portion 10C. An O-ring 14 is disposed in the groove 6a, and the O-ring 14 is connected to the upper end of the housing 10 and the body. The gap with 1 is filled.

  The cover 15 is formed in a cylindrical shape, and the upper end of the cover 15 is inserted into a gap 16 formed between the inner peripheral side wall on the lower end side of the cylindrical portion 10 </ b> B of the housing 10 and the outer peripheral surface of the body 1. In this state, the gap 16 is filled with the sealing material 18 so that the space between the body 1 and the lower end of the housing 10 is sealed and the cover 15 is fixed. And the clearance gap 17 is formed by the lower end peripheral wall of the inner surface side of the cover 15 which has covered the outer peripheral surface of the coil bobbin 2, and the outer peripheral surface of the lower end of the coil bobbin 2, By filling the clearance gap 17 with the sealing material 18, By the cover 15, the coil bobbin 2, and the sealing material 18, a sealing structure can be easily configured with few parts. As described above, the opening 13 of the housing 10 that houses the control board 3 is sealed.

  In the proximity sensor of the present embodiment having the above-described configuration, power is supplied to the control board 3 via the input / output terminal 4 when the input / output connector 4 is connected to an external power source. And the control board 3 converts the said power supply into high frequency electric power, and outputs it to the coil 9, and the coil 9 generate | occur | produces a high frequency electromagnetic field. Here, when an object to be detected such as a metal or a magnetic material approaches the coil 9, the magnetic flux of the coil 9 changes to change the conductance, and the voltage or current applied to the coil 9 changes. Then, when the control board 3 detects the change and the amount of change exceeds the threshold value, a detection signal is output from the detection signal output terminal of the input / output connector 4. In this way, since the detection target can be detected in a non-contact manner without the shaft of the sensor being pressed by the sensor shaft as in a conventionally used sensor, no impact is applied to the sensor.

  Further, when the proximity sensor of the present embodiment is attached to a structure or the like, a screw groove formed on the outer periphery of the cylindrical portion 10C of the housing 10 is screwed into a screw hole or the like formed in the structure. , Supported and fixed to the structure. At this time, a washer 20 is disposed between the proximity sensor and the structure to prevent loosening.

  Since the coil bobbin 2 around which the coil 9 is wound is formed integrally with the body 1, the relative position between the coil 9 and the body 1 is unlikely to vary, and the distance from the coil 9 to the object to be detected varies. Therefore, the detection accuracy can be improved. In addition, since the coil 9 that detects the detection target is provided at the tip portion of the sensor, the distance from the coil 9 to the detection target is short, and detection can be performed with higher accuracy.

  From the above, the proximity sensor according to the present embodiment does not transmit an impact at the time of detection, and can suppress variation in detection accuracy and improve detection accuracy.

  In addition, the core 8 may be integrally formed inside the coil bobbin 2, and in this case, it is easy to assemble by eliminating the trouble of assembling the core 8 to the coil bobbin 2, and in addition, the accuracy of the position where the core 8 is fixed. Can improve detection accuracy.

  Moreover, the proximity sensor of this embodiment is used, for example, for detecting the neutral position of the gear of an automobile. For example, as shown in FIGS. 8A to 8C, when the detection body 19 made of metal is rotating in the vicinity of the coil 9 in accordance with the position of the gear, the detection unit 19a of the detection body 19 is detected. However, when the position is away from the coil 9 (when the gear is not in the neutral position), the proximity sensor does not output a detection signal (see FIGS. 6A and 6C), but the detection body 19 When the detection unit 19a approaches the coil 9, the proximity sensor outputs a detection signal, and the ECU that has received the detection signal stops the engine.

Sectional drawing of the proximity sensor in this embodiment is shown. (A)-(c) shows the 3rd figure of the proximity sensor in the same as the above, (a) is a front view, (b) is a top view, (c) shows a bottom view. (A), (b) shows the internal structure figure of the proximity sensor in the same as the above, (a) shows the internal structure seen from back, and (b) shows a sectional view. The perspective view of the proximity sensor in the same as the above is shown. (A)-(e) shows the 4th page figure and sectional drawing of the body in the same as the above, (a) is a front view, (b) is a rear view, (c) is a top view, (d) is a top view. , Bottom view, (e) shows a cross-sectional view. Sectional drawing of the body in the same as the above is shown. (A), (b) shows the attachment state of the control circuit to the body in the same as above, (a) shows before attachment, and (b) shows after attachment. (A)-(c) shows the motion of the detection body approaching the proximity sensor in the same as above, (a) is before approaching, (b) is nearing, and (c) is when leaving.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body 2 Coil bobbin 3 Control circuit 4 Input / output connector 9 Coil 10 Housing 15 Cover 16 Gap 17 Gap 18 Seal material

Claims (3)

A coil bobbin around which a coil is wound;
A control circuit that generates a high-frequency electromagnetic field in the coil and generates a detection signal in accordance with a change in the high-frequency electromagnetic field due to the detection object approaching the coil;
An input / output connector that outputs a detection signal of the control circuit and supplies power to the control circuit;
A body to which the control circuit and the input / output connector are attached ;
A cylindrical cover for storing the coil bobbin ;
The coil bobbin and body are integrally molded ,
A proximity sensor , wherein a gap between the cover and the tip of the coil bobbin is filled with a sealing material . A cylindrical housing that is attached to the body and houses the control circuit is provided, and a gap is formed between the opening peripheral edge of the housing located on the coil bobbin side of the control circuit and the body, and one end of the cover is inserted into the gap The proximity sensor according to claim 1, wherein the gap is filled with a sealing material. The proximity sensor according to claim 1, wherein a core of the coil bobbin is integrally formed.

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