Position detection sensor

Abstract

SOLUTION: A position detection sensor 30 for detecting a position of a piston 14 in an actuator 10 includes: a sensor element 52 for detecting a magnet 20 mounted on the piston 14; a housing 50 for accommodating the sensor element 52; a magnetic body 66 or 74 displaced to a position corresponding to a position of the magnet 20; and an accommodating portion 64 or 72 that is provided in the housing 50 and visually recognizably accommodates the magnetic body.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a position detection sensor.

Background Art

[0002] A position detection sensor is attached to the outer surface of an actuator. A magnet is attached to a piston in the actuator, and the position detection sensor is provided with a magnetic sensor for detecting the magnet. The attachment position of the position detection sensor is adjusted, for example, to detect that the piston is located at one end of the movable range of the piston.

[0003] Patent Document 1 shows an auto-switch (position detection sensor) indicating the highest sensitivity position of a magnetic sensor, and a cylinder having a scale marked on the outer surface in accordance with the highest sensitivity position of the magnetic sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technology of Patent Document 1, although the highest sensitivity position of the magnetic sensor is known, the position of the piston in the cylinder is not known. For this reason, the optimal attachment position of the position detection sensor with respect to the actuator is not known.

[0006] An object of the present invention is to solve the above-described problems.

Means for Solving the Problems

[0007] Aspects of the present disclosure relate to a position detection sensor attached to an actuator, comprising a sensor element for detecting a magnet attached to a piston within the actuator, a housing for housing the sensor element, a magnetic body that is displaced to a position corresponding to the position of the magnet, and a housing portion provided in the housing for visibly housing the magnetic body.

Advantages of the Invention

[0008] According to the present invention, an optimal attachment position of the position detection sensor with respect to the actuator can be specified.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0010] The piston within the actuator moves between a first end and a second end within the movable range of the piston. There may be a case where it is desired to detect by the position detection sensor that the piston within the actuator has moved to the first end. In this case, when the piston is positioned at the first end, the attachment position of the position detection sensor may be adjusted so that the output of the magnetic sensor is maximized. In order to obtain an output from the magnetic sensor, power needs to be supplied to the magnetic sensor, and thus such a position adjustment method is premised on the supply of power to the magnetic sensor.

[0011] In recent years, position detection sensors using wireless power transfer have been developed. In such a position detection sensor, the magnetic sensor does not operate when wireless power transfer is not being performed. Therefore, when wireless power transfer is not being performed, the optimal mounting position of the position detection sensor with respect to the actuator cannot be specified using the magnetic sensor.

[0012] According to the embodiment described below, even when wireless power transfer is not being performed, the optimal mounting position of the position detection sensor with respect to the actuator can be specified.

[0013] [First Embodiment] The position detection sensor 30 according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic diagram of the actuator 10 and the position detection sensor 30 according to the first embodiment. In FIG. 1, a cross section of the actuator 10 is shown, and a side surface of the position detection sensor 30 is shown. FIG. 2 is a functional block diagram of the position detection sensor 30. FIG. 3 is an arrangement diagram of the magnetic sensor (sensor element) 52, the light emitting element 54, and the light emission window 62.

[0014] As shown in FIG. 1, the actuator 10 includes a cylinder 12, a piston 14, and a rod 16. The piston 14 is movable between a first end portion 18 and a second end portion (not shown) of the pressure chamber of the cylinder 12. An annular magnet 20 is attached to the outer periphery of the piston 14. One end portion of the rod 16 is connected to the piston 14. The other end portion of the rod 16 is disposed outside the cylinder 12 and connected to another machine.

[0015] As shown in FIG. 1, the position detection sensor 30 is attached to the outer surface of the actuator 10. In this specification, the position detection sensor 30 is attached to the upper surface 22 of the actuator 10. Note that the position detection sensor 30 may be attached to an outer surface other than the upper surface 22. The position detection sensor 30 is detachable from the upper surface 22 of the actuator 10.

[0016] The position detection sensor 30 detects the position of the piston 14 within the actuator 10. More specifically, the position detection sensor 30 detects the piston 14 positioned at the first end portion 18 within the actuator 10. Further, the position detection sensor 30 transmits a signal indicating that the piston 14 is positioned at the first end portion 18 to an external device such as a PLC (Programmable Logic Controller).

[0017] As shown in FIG. 2, the position detection sensor 30 includes a magnetic detection unit 32, a control unit 34, a communication unit 36, a power receiving unit 38, a light emitting unit 40, and a switch unit 42. The magnetic detection unit 32 can be constituted by, for example, a magnetic sensor 52 (FIGS. 1 and 3). The magnetic detection unit 32 detects the magnetism of the magnet 20 attached to the piston 14 within the actuator 10. The magnetic detection unit 32 outputs a signal indicating the magnetism to the control unit 34. The control unit 34 can be constituted by, for example, a processor and a memory. The control unit 34 controls the communication unit 36 and the switch unit 42. The communication unit 36 can be constituted by a communication module including a communication circuit for performing short-range wireless communication, for example. The communication unit 36 transmits a signal indicating that the piston 14 (magnet 20) is positioned at the first end portion 18 of the cylinder 12 to an external device (such as a PLC).

[0018] The power receiving unit 38 can be constituted by, for example, a circuit for receiving power supplied wirelessly. The wireless power supply may be performed by any one of electromagnetic induction, electric field coupling, and electromagnetic waves (microwaves, lasers). The power receiving unit 38 can receive power wirelessly supplied from a wireless power supply device (not shown). The power receiving unit 38 receives the power supplied from the wireless power supply device via an antenna (not shown). The power receiving unit 38 may be provided with a rectifying circuit or the like (not shown). The rectifying circuit or the like rectifies the AC power received from the wireless power supply device and generates DC power. The power receiving unit 38 can supply DC power to each component of the position detection sensor 30.

[0019] The light emitting unit 40 can be constituted by, for example, a light emitting element 54 (FIG. 3). For example, when the piston 14 of the actuator 10 is located at the first end portion 18, the light emitting unit 40 emits light. On the other hand, when the piston 14 of the actuator 10 is located at a portion other than the first end portion, the light emitting unit 40 does not emit light. The switch unit 42 switches the electrical connection state (light emission) and the electrical disconnection state (non-light emission) between the power receiving unit 38 and the light emitting unit 40 according to a signal supplied from the control unit 34.

[0020] As shown in FIGS. 1 and 3, the position detection sensor 30 includes a housing 50, a magnetic sensor 52, a light emitting element 54, and a magnet detection member 56. Each component (for example, the magnetic sensor 52, the light emitting element 54, etc.) of the magnetic detection unit 32, the control unit 34, the communication unit 36, the power receiving unit 38, the light emitting unit 40, and the switch unit 42 shown in FIG. 2 is housed in the housing 50. With the position detection sensor 30 mounted on the upper surface 22 of the actuator 10, the side surface 58 of the housing 50 is parallel to the moving direction of the piston 14 of the actuator 10.

[0021] As shown in FIG. 3, a light emission window 62 is formed in the top plate 60 of the housing 50. The light emission window 62 emits the light emitted by the light emitting element 54 inside the housing 50 to the outside of the housing 50. In plan view, the light emission window 62, the light emitting element 54, and the magnetic sensor 52 overlap each other. That is, the position of the light emission window 62 in the moving direction of the piston 14, the position of the light emitting element 54 in the moving direction of the piston 14, and the position of the magnetic sensor 52 in the moving direction of the piston 14 are the same. For this reason, the light emission window 62 and the light emitting element 54 serve as marks indicating the position of the magnetic sensor 52 in the moving direction of the piston 14.

[0022] Note that, in plan view, the light emission window 62 and the magnetic sensor 52 do not have to overlap each other. In this case, it is preferable that a mark indicating the position of the magnetic sensor 52 in the moving direction of the piston 14 is provided on the outer surface of the housing 50.

[0023] The magnet detection member 56 is sheet-shaped. The magnet detection member 56 is detachable from the side surface 58 of the housing 50. Note that the magnet detection member 56 may be attached to the side surface 58 of the housing 50. The magnet detection member 56 includes an encapsulating member 64 (accommodating portion) and a magnetic fluid 66 (magnetic body).

[0024] The encapsulating member 64 is attached to the side surface 58 of the housing 50. The encapsulating member 64 includes two sheet members. The outer edges of the two sheet members are adhered to each other. The encapsulating member 64 accommodates the magnetic fluid 66 between the two sheet members. Among the two sheet members, the sheet member that does not contact the housing 50 needs to be transparent (or translucent). Since a transparent sheet member is used, the magnetic fluid 66 inside the encapsulating member 64 can be visually recognized from outside the position detection sensor 30.

[0025] The magnetic fluid 66 is, for example, iron sand. Since the magnetic fluid 66 is a magnetic body, it is attracted to the magnet 20 attached to the piston 14 in the actuator 10. The magnetic fluid 66 is movable inside the encapsulating member 64. With the position detection sensor 30 attached to the upper surface 22 of the actuator 10, the magnetic fluid 66 follows the magnet 20 and moves in the moving direction of the magnet 20 (piston 14). The magnetic fluid 66 gathers at a portion close to the magnet 20 within the encapsulating member 64. The position where the magnetic fluid 66 gathers indicates the position of the magnet 20 in the moving direction of the piston 14.

[0026] As described above, the position detection sensor 30 according to the first embodiment includes a mark (e.g., a light emission window 62) on the outer surface of the housing 50 that indicates the position of the magnetic sensor 52 in the moving direction of the piston 14. Further, the position detection sensor 30 includes a magnet detection member 56 for making the position of the piston 14 (magnet 20) in the moving direction of the piston 14 visible.

[0027] With the piston 14 positioned at the first end portion 18, the user aligns the position detection sensor 30 so that a mark (for example, the light emission window 62) coincides with the concentration position of the magnetic fluid 66. Thereby, the optimal attachment position of the position detection sensor 30 with respect to the actuator 10 can be specified. Accordingly, the position detection sensor 30 can be attached to the actuator 10 at an optimal position.

[0028] [Second Embodiment] FIG. 4 is a schematic view of the actuator 10 and the position detection sensor 30 according to the second embodiment. The position detection sensor 30 includes a groove 72 (accommodating portion) and a sphere 74 (magnetic body) on the side wall portion 70. Regarding the configuration of the second embodiment, the parts different from the configuration of the first embodiment will be described.

[0029] The groove 72 is formed so as to be recessed from the side surface 58 of the side wall portion 70. The groove 72 has an opening 76 at a portion flush with the side surface 58. The groove 72 and the opening 76 are formed along the longitudinal direction of the side surface 58 of the housing 50. In a state where the position detection sensor 30 is attached to the upper surface 22 of the actuator 10, the extending direction of the groove 72 and the opening 76 is parallel to the moving direction of the piston 14 of the actuator 10. The groove 72 accommodates the sphere 74. The dimension of the opening 76 in the short direction of the side surface 58 is smaller than the diameter of the sphere 74. For this reason, the sphere 74 accommodated in the groove 72 does not fall off from the opening 76. A part of the sphere 74 accommodated in the groove 72 is exposed through the opening 76. By providing the opening 76, the sphere 74 inside the groove 72 can be visually recognized from the outside of the position detection sensor 30.

[0030] Note that the groove 72 may not be formed in the side wall portion 70. A member having the groove 72 formed therein may be attached to the side wall portion 70 of the position detection sensor 30 via a surface fastener or the like. Further, the sphere 74 may be removable from the housing 50. For example, a detachable lid member may be provided at the end of the groove 72, and the sphere 74 may be insertable into and removable from the groove 72 with the lid member removed.

[0031] Since the sphere 74 is a magnetic material such as a steel ball, it is attracted to the magnet 20 attached to the piston 14 in the actuator 10. The sphere 74 is movable along the groove 72. With the position detection sensor 30 mounted on the upper surface 22 of the actuator 10, the sphere 74 moves following the magnet 20 in the moving direction of the magnet 20 (piston 14). The sphere 74 is located at a site close to the magnet 20. The position of the sphere 74 indicates the position of the magnet 20 in the moving direction of the piston 14.

[0032] Similar to the first embodiment, the position detection sensor 30 according to the second embodiment includes a mark (for example, a light emission window 62) on the outer surface of the housing 50 indicating the position of the magnetic sensor 52 in the moving direction of the piston 14. Further, the position detection sensor 30 includes a groove 72 and a sphere 74 for making visible the position of the piston 14 (magnet 20) in the moving direction of the piston 14.

[0033] With the piston 14 stopped at the first end 18, the user adjusts the position of the position detection sensor 30 so that the mark (for example, the light emission window 62) coincides with the stop position of the sphere 74. Thereby, the optimum mounting position of the position detection sensor 30 with respect to the actuator 10 can be specified. Accordingly, the position detection sensor 30 can be mounted at an optimum position with respect to the actuator 10.

[0034] [Others] The position detection sensor 30 according to each embodiment may receive power supplied by wire instead of receiving wirelessly supplied power. Further, the position detection sensor 30 may include a battery instead of receiving wirelessly supplied power.

[0035] [Supplementary Note] Regarding the above embodiment, the following supplementary note is further disclosed.

[0036] (Supplementary Note 1) The position detection sensor (30) of the present disclosure is a position detection sensor attached to an actuator (10), and includes a sensor element (52) that detects a magnet (20) attached to a piston (14) in the actuator, a housing (50) that houses the sensor element, a magnetic body (66, 74) that is displaced to a position corresponding to the position of the magnet, and a housing portion (64, 72) that is provided in the housing and visually accommodates the magnetic body.

[0037] According to the above configuration, regardless of whether the power supply is wired or wireless, the optimal attachment position of the position detection sensor to the actuator can be specified. Therefore, the position detection sensor can be attached to the actuator at an optimal position.

[0038] (Appendix 2) In the position detection sensor described in Appendix 1, a mark indicating a position corresponding to the position of the magnet when the output of the sensor element is maximum may be provided.

[0039] (Appendix 3) In the position detection sensor described in Appendix 1 or 2, a light emitting element (54) that indicates by light emission that the magnet has been detected is provided, and the position corresponding to the position of the magnet when the output of the sensor element is maximum and the position of the light emitting element may coincide.

[0040] According to the above configuration, it is not necessary to mark the housing only for indicating the position of the sensor. For this reason, the appearance of the position detection sensor becomes simple.

[0041] (Appendix 4) In the position detection sensor described in any one of Appendices 1 to 3, the magnetic body may be a magnetic fluid (66).

[0042] (Appendix 5) In the position detection sensor described in any one of Appendices 1 to 3, the magnetic body may be a sphere (74).

[0043] (Appendix 6) In the position detection sensor according to any one of Appendices 1 to 5, the magnetic body and the housing portion may be detachable from the housing.

[0044] (Appendix 7) In the position detection sensor according to any one of Appendices 1 to 3, the magnetic body may be detachable from the housing portion.

[0045] According to the above configuration, after the alignment of the position detection sensor is completed, the magnetic body and the housing portion can be removed from the housing. Therefore, the appearance of the position detection sensor becomes simple.

[0046] Although the present disclosure has been described in detail, the present disclosure is not limited to the above-described individual embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc., without departing from the gist of the present disclosure or without departing from the gist of the present disclosure derived from the content described in the claims and its equivalents. Also, these embodiments can be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as an example and are not limited thereto. The same applies when numerical values or mathematical formulas are used in the description of the above-described embodiments.

Description of Reference Numerals

[0047] 10…Actuator 14…Piston 20…Magnet 30…Position Detection Sensor 50…Housing 52…Magnetic Sensor (Sensor Element) 54…Light-Emitting Element 64…Enclosing Member (Housing Portion) 66…Magnetic Fluid (Magnetic Body) 72…Groove (Housing Portion) 74…Sphere (Magnetic Body)

Claims

1. A position detection sensor attached to an actuator, comprising: a sensor element that detects a magnet attached to a piston within the actuator; a housing that houses the sensor element; a magnetic body that is displaced to a position corresponding to the position of the magnet; a housing portion provided in the housing and accommodating the magnetic body in a visually recognizable manner; A position detection sensor comprising the above.

2. The position detection sensor according to Claim 1, further comprising: a mark indicating a position corresponding to the position of the magnet when the output of the sensor element is maximum.

3. The position detection sensor according to Claim 1, further comprising: a light emitting element that indicates by light emission that the magnet has been detected; A position detection sensor in which the position corresponding to the position of the magnet when the output of the sensor element is maximum coincides with the position of the light emitting element.

4. The position detection sensor according to any one of Claims 1 to 3, wherein: the magnetic body is a magnetic fluid.

5. The position detection sensor according to any one of Claims 1 to 3, wherein: the magnetic body is a sphere.

6. The position detection sensor according to any one of Claims 1 to 3, wherein: the magnetic body and the housing portion are detachable from the housing.

7. The position detection sensor according to any one of Claims 1 to 3, wherein: the magnetic body is detachable from the housing portion.

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