Sensor module

Abstract

To provide a sensor module capable of reducing side lobes of radio waves that adversely affect the accuracy of detecting a remaining amount at a low cost.SOLUTION: A sensor module 100 that is attached to an opening portion 2 of a container 1 in which contents 5 are accommodated comprises a cap 3 and a sensor portion 20. The cap 3 has: a lid portion 3a that closes the opening portion 2; a lens portion 32; a support wall 33 that is disposed standing upright around the lens portion 32 and supports the sensor portion 20; and a side wall 36. The sensor portion 20 has a transmission / reception portion 21 including a transmission portion 21a and a reception portion 21b. The lens portion 32 is disposed so as to face the transmission / reception portion 21 of the sensor portion 20, the transmission portion 21a transmits radio waves that pass through the lens portion 32 and reach an internal space 1a of the container 1, and the reception portion 21b receives reflected waves after the radio waves are reflected by the contents 5 in the internal space 1a. The side wall 36 is disposed standing upright, in the same direction as the support wall 33 around the lens portion 32.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a sensor module.

Background Art

[0002] For example, in cold regions such as Hokkaido, kerosene is used as the fuel for the main heating appliances in buildings. In order to continuously use the heating appliances in winter, a fuel tank installed outdoors and capable of supplying kerosene from the outdoors to the indoor heating appliances is often used as the supply source of kerosene to the heating appliances. However, in order to continuously use the heating appliances, it is desirable to replenish the kerosene before it runs out, rather than replenishing it after the kerosene in the fuel tank runs out. Therefore, some fuel tanks are equipped with dedicated remaining amount detection sensors.

[0003] Patent Document 1 discloses a radar water level measuring device using a radar signal. This radar water level measuring device has an antenna unit that radiates a radar signal to a water level interface and receives the radar signal reflected from the water level interface, and a control unit that performs transmission control for the radar signal radiated by the antenna unit, reception control for the radar signal received by the antenna unit, and water level measurement control using the received radar signal. The antenna unit has a lens for transmitting and receiving the radar signal in a direction perpendicular to the water level interface, and an absorber for reducing the side lobe of the radar signal transmitted and received through the lens.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The radar water level measuring device described in Patent Document 1 can reduce the side lobes of the radar signal transmitted in the waveguide and lens directions by an absorber, but cannot reduce the side lobes of the radar signal transmitted in other directions by an absorber. Further, in this radar water level measuring device, since a separate component such as a waveguide is used, the number of components of the device increases, the assembly man-hours increase, and there is a risk of cost increase.

[0006] Therefore, a sensor module that can reduce the side lobes of radio waves that can reduce the cost and have an adverse effect on the detection accuracy of the remaining amount is desired.

Means for Solving the Problem

[0007] One embodiment of the sensor module according to the present disclosure is a sensor module attached to an opening of a container in which a container is accommodated, and includes a cap and a sensor unit. The cap has a lid portion that closes the opening, a lens portion, a support wall that stands around the lens portion and supports the sensor unit, and a side wall. The sensor unit has a transmission / reception unit that includes a transmission unit that transmits radio waves and a reception unit that receives the radio waves. The lens portion is arranged to face the transmission / reception unit of the sensor unit. The transmission unit transmits the radio waves that pass through the lens portion and reach the internal space of the container. The reception unit receives a reflected wave after the radio waves are reflected by the container in the internal space. The side wall is arranged to stand in the same direction as the support wall around the lens portion.

[0008] According to this embodiment, since the sensor module is arranged at the opening of the container, there is no need to modify the container to arrange the sensor module in the existing container, and the remaining amount of the contents contained in the container can be detected as it is. Further, since the remaining amount of the contents is calculated using radio waves, the remaining amount of the contents can be easily detected at set time intervals. Furthermore, between the lens unit and the support wall erected and arranged around the lens unit, and a side wall is erected in the same direction as the support wall around the lens unit, so that the side lobe of the radio wave transmitted from the transmitting unit can be suppressed from adversely affecting the reflected wave. By making the side wall a part different from the support wall, the position where the side wall is arranged can be freely set according to the generation situation of the side lobe. Since the support wall needs to support and fix the sensor unit, when arranging the side wall on the support wall, there may be restrictions on the position and shape of the side wall.

[0009] In another embodiment of the sensor module according to the present disclosure, the sensor unit further includes an arithmetic unit that calculates the remaining amount of the contents or information for calculating the remaining amount based on the time from when the radio wave is transmitted from the transmitting unit until the reflected wave is received by the receiving unit.

[0010] According to this embodiment, the arithmetic unit calculates the remaining amount of the contents or information for calculating the remaining amount by calculating the time until the radio wave is directly reflected by the contents and received, so that the remaining amount of the contents or information for calculating the remaining amount can be detected with high resolution by one sensor module.

[0011] Another embodiment of the sensor module according to the present disclosure further includes an external communication unit, and the external communication unit wirelessly transmits an external signal indicating the remaining amount of the contents or the information for calculating the remaining amount calculated by the arithmetic unit.

[0012] According to this embodiment, the sensor module can know the remaining amount of the contents at a location away from the container without visually checking the inside of the container.

[0013] Another embodiment of the sensor module according to the present disclosure further includes a power supply unit that supplies power to the sensor unit and the external communication unit.

[0014] According to this embodiment, the sensor module can continue to operate without using an external power supply.

[0015] Another embodiment of the sensor module according to the present disclosure further includes a housing detachably configured with the cap, and the sensor unit is housed in a closed space formed by the cap and the housing.

[0016] According to this embodiment, since the cap and the housing are detachable, for example, when the sensor unit fails, the housing can be removed from the cap to repair, replace, etc. the sensor unit.

[0017] Another embodiment of the sensor module according to the present disclosure is that the side wall is integrally formed with the lid portion.

[0018] According to this embodiment, compared with the case where the lid portion and the side wall are manufactured separately and the cap is assembled, the cap can be manufactured with less man-hours and lower costs. In addition, a cap with high positional accuracy of the side wall with respect to the lid portion can be obtained.

[0019] In another embodiment of the sensor module according to the present disclosure, the side wall is cylindrical.

[0020] According to this embodiment, regardless of the direction in which the side lobe of the radio wave is transmitted from the transmitting unit, the side lobe that affects the reflected wave can be reduced. In addition, there are no restrictions on the mounting direction of the transceiver unit, etc., and the degree of freedom in assembling the sensor module increases.

[0021] In another embodiment of the sensor module according to the present disclosure, the radio wave transmitted from the transmitting unit is a millimeter wave.

[0022] According to this embodiment, by using millimeter waves as radio waves, the radio waves can penetrate the resin. Therefore, in the resin cap of the container, even if the sensor module is arranged outside the cap, the remaining amount of the contents in the container can be calculated through the cap. If the radio waves are light such as infrared rays or visible light, a part or all of the cap must be formed of a transparent or translucent resin or holes must be made in the cap for the radio waves to pass through the cap. However, by using millimeter waves as the radio waves, it is not necessary to use a transparent or translucent material or make holes in the cap.

Brief Description of Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0024] Hereinafter, embodiments of the sensor module according to the present disclosure will be described in detail with reference to the drawings. It should be noted that the embodiments described below are examples for explaining the sensor module, and the sensor module is not limited to these embodiments. Therefore, the sensor module according to the present disclosure can be implemented in various forms without departing from the gist thereof.

[0025] 〔Configuration of Sensor Module〕 As shown in FIG. 1, the sensor module 100 according to the present embodiment is used by being attached to the outside of the opening 2 of the fuel tank 1 (an example of a container). The fuel tank 1 includes a tank body 1b and a cylindrical opening 2 protruding from the tank body 1b. The internal space 1a of the tank body 1b communicates with the inner space of the opening 2, and kerosene 5 (an example of the stored substance) is poured from the opening 2 and supplied to the internal space 1a. Thereby, kerosene 5 is stored in the internal space 1a. The sensor module 100 detects the remaining amount of kerosene 5 stored in the internal space 1a of the fuel tank 1 or information for calculating the remaining amount (hereinafter, these are referred to as "remaining amount, etc."). The cap 3 is made of resin and is screwed onto the opening 2 to close the opening 2. Note that the engagement between the cap 3 and the opening 2 is not limited to screwing, and any method can be adopted.

[0026] As shown in FIGS. 2 to 4, the sensor module 100 includes a cap 3, a housing 10, a sensor unit 20, a power supply unit 60, and an external communication IC 90 (an example of an external communication unit).

[0027] The sensor unit 20 includes a transceiver IC 21 (an example of a transceiver unit) and an arithmetic IC 22 (an example of an arithmetic unit). As shown in FIGS. 2 and 3, the transceiver IC 21 and the arithmetic IC 22 are respectively mounted on different surfaces of the plate surface of the first substrate 40. The transceiver IC 21 has a transmission unit 21a and a reception unit 21b. Note that the transceiver IC 21 and the arithmetic IC 22 may be mounted on the same surface of the first substrate 40.

[0028] The transmission unit 21a of the transceiver IC 21 has a function of transmitting an externally modulated radio wave of the signal to be transmitted, and the reception unit 21b has a function of demodulating a radio wave from the outside and receiving the signal. The transceiver IC 21 can receive the radio wave transmitted from the transmission unit 21a by the reception unit 21b. The transceiver IC 21 mounted on the first substrate 40 modulates the signal to be transmitted and transmits a radio wave from a transmission antenna (not shown) of the transmission unit 21a, and demodulates the radio wave received from a reception antenna (not shown) of the reception unit 21b. The arithmetic IC 22 has a function of calculating the remaining amount of the kerosene 5 stored in the internal space 1a of the fuel tank 1 based on the time until the radio wave transmitted from the transmission antenna is received by the reception antenna.

[0029] The power supply unit 60 includes a power supply IC 61 and a battery unit 62. The power supply IC 61 is mounted on the same surface as the surface on which the arithmetic IC 22 of the first substrate 40 is mounted. The battery unit 62 includes a battery 62a and a battery socket 62b that holds the battery 62a. The battery socket 62b holding the battery 62a is mounted on the plate surface of the second substrate 50. The transceiver IC 21, the arithmetic IC 22, the power supply IC 61, and the external communication IC 90 mounted on the first substrate 40 operate by receiving power supply from the battery 62a mounted on the second substrate 50. The battery unit 62 may be a secondary battery or a combination of a self-power generating device and a secondary battery. Note that the power supply IC 61 may be mounted on a surface different from the surface on which the arithmetic IC 22 of the first substrate 40 is mounted. Also, when the sensor module 100 does not include the second substrate 50, the battery unit 62 may be configured to be mounted on the first substrate 40.

[0030] The external communication IC 90 is mounted on the same surface as the surface on which the battery unit 62 of the second substrate 50 is mounted. On the same surface as the surface on which the external communication IC 90 of the second substrate 50 is mounted, an external communication antenna 91 for transmitting the signal generated by the external communication IC 90 to the outside is formed in a pattern. The external communication antenna 91 may be configured using a dedicated antenna component instead of a pattern, or may be built into the external communication IC 90. Further, when the sensor module 100 does not include the second substrate 50, the external communication IC 90 may be configured to be mounted on the first substrate 40.

[0031] As shown in FIGS. 2 and 4, the first substrate 40 and the second substrate 50 are electrically connected by a connection member 80. The connection member 80 may be any member that electrically connects between the first substrate 40 and the second substrate 50, such as an FFC (Flexible Flat Cable) or an FPC (Flexible Printed Circuit). At this time, connectors 82 to which both ends of the connection member 80 are electrically connected are mounted on the first substrate 40 and the second substrate 50. That is, the first substrate 40 and the second substrate 50 are electrically connected by the connector 82 mounted on the first substrate 40, the connection member 80, and the connector 82 mounted on the second substrate 50. Note that, instead of the above configuration, it may be configured by a harness composed of an electric wire and a plug and receptacles mounted on the first substrate 40 and the second substrate 50, respectively, or may be configured by a board-to-board connection connector, or may have other configurations.

[0032] Hereinafter, as shown in FIGS. 1 to 4, the sensor unit 20 including the first substrate 40, the arithmetic IC 22, the power supply IC 61, the battery unit 62 including the second substrate 50, the external communication IC 90, and the connection member 80 and the connectors 82, 82 are referred to as a sensor assembly 70. That is, the sensor assembly 70 is a general term for an assembly product including the sensor unit 20, the power supply unit 60, the external communication IC 90, and the first substrate 40 and the second substrate 50 on which they are mounted and electrically connected by the connection member 80. Thus, it can be paraphrased that the sensor module 100 is configured to include the cap 3, the housing 10, and the sensor assembly 70.

[0033] The cap 3 is composed of a lid portion 3a, a fixing portion 3b, a lens portion 32, a support wall 33, and a side wall 36. The cap 3 is made of resin, and the lid portion 3a, the fixing portion 3b, the lens portion 32, the support wall 33, and the side wall 36 may be individually molded, or at least two of them may be integrally formed. When integrally formed, specifically, the cap 3 is formed by supplying molten resin to one mold and curing it.

[0034] The lid portion 3a has a bottomed cylindrical shape, and an internal thread is formed on the inner surface (see FIGS. 3 and 4). By screwing the internal thread with an external thread formed on the outer surface of the opening 2 of the fuel tank 1 (see FIGS. 1 and 4), the cap 3 is fixed to the fuel tank 1. The method of fixing the cap 3 to the fuel tank 1 is not limited to screwing the lid portion 3a and the opening 2, and other methods may be used. The lens portion 32, the support wall 33, and the side wall 36 are formed on the bottom wall 31 of the lid portion 3a. The support wall 33 is formed so as to stand upright from the fixing portion 3b toward the side opposite to the side where the opening 2 is disposed.

[0035] The fixing portion 3b extends radially outward from the side surface of the lid portion 3a. The outer edge of the fixing portion 3b is a first peripheral wall 3d standing upright in the radial direction, and an internal thread 3e is formed on the inner peripheral surface of the first peripheral wall 3d.

[0036] The lens unit 32 stands upright from the bottom wall 31 of the lid portion 3a and is disposed at a position facing the transmission / reception IC 21 of the sensor unit 20. In the present embodiment, the transmission / reception IC 21 and the top surface 32a of the lens unit 32 are in close contact. However, the transmission / reception IC 21 and the top surface 32a of the lens unit 32 may be separated. The lens unit 32 exhibits a lens function by changing its thickness and shape. Since the cap 3 has the lens unit 32, the efficiency of transmission and reception of radio waves from the transmission / reception IC 21 can be enhanced. Specifically, the lens unit 32 is configured by stacking a plurality (for example, three) of cylinders whose outer diameter becomes smaller toward the transmission / reception IC 21 from the bottom wall 31. The lens unit 32 in the present embodiment has a convex lens shape, but may have a concave lens shape, may stand upright toward the side opposite to the bottom wall 31, or may stand upright toward both sides, and any lens shape can be adopted according to the purpose. Further, the lens unit 32 may not have a lens function. Note that the bottom wall 31 of the lid portion 3a integrally formed with the lens unit 32 may function as a part of the lens unit 32.

[0037] The support wall 33 is disposed around the lens unit 32 and has a cylindrical shape standing upright from the outer edge of the bottom wall 31. At the tip of the support wall 33, a plurality (four in the present embodiment) of support bosses 34 extending along the standing direction of the support wall 33 are integrally formed and are arranged to be evenly distributed in the circumferential direction of the support wall 33. The first substrate 40 and the second substrate 50 are fixed to the cap 3 by being supported by the support bosses 34. Through holes are formed in the first substrate 40 and the second substrate 50 at positions corresponding to the support bosses 34, and the support bosses 34 penetrate through the through holes. The support bosses 34 may not be plural, and may be single. Note that the support bosses 34 may be arranged by a method such as press-fitting or adhesion to the support wall 33. Note that the support bosses 34 may be arranged unevenly in the circumferential direction of the support wall 33.

[0038] In this embodiment, the first substrate 40 is fixed to the cap 3 by the support bosses 34 so that the transceiver IC 21 abuts on the top surface 32a of the lens unit 32. That is, the lens unit 32 protrudes by a height such that the transceiver IC 21 abuts on the top surface 32a when the first substrate 40 is fixed to the cap 3. As a method of fixing the first substrate 40 and the second substrate 50 to the cap 3 by the support bosses 34, for example, the tip of the support boss 34 may be heated and melted and thermally welded to the second substrate 50. Also, the tip of the support boss 34 may be formed in a split pin shape to fix the first substrate 40 and the second substrate 50. Alternatively, a female thread may be formed at the tip of the support boss 34 and fixed with a male thread, or the support boss 34 may be omitted and fixed to the support wall 33 with a male thread. Any method can be adopted as long as the first substrate 40 and the second substrate 50 can be fixed to the cap 3.

[0039] With the first substrate 40 supported by the support bosses 34, a spacer 42 inserted through the support bosses 34 is disposed between the first substrate 40 and the second substrate 50. By this spacer 42, the first substrate 40 and the second substrate 50 are arranged to be separated from each other by the length of the spacer 42. Also, instead of the above configuration, regarding the outer diameter of the support boss 34, the base end portion may have a large diameter and the tip end portion may have a small diameter, and a step may be provided between the base end portion and the tip end portion. Then, a through hole having an inner diameter through which the base end portion of the support boss 34 can be inserted is formed in the first substrate 40, and a through hole having an inner diameter through which the tip end portion of the support boss 34 can be inserted but the base end portion cannot be inserted is formed in the second substrate 50. Thereby, when the first substrate 40 and the second substrate 50 are inserted through the support boss 34, the second substrate 50 is supported by the step between the base end portion and the tip end portion of the support boss 34, so that the first substrate 40 and the second substrate 50 are fixed in a separated state even without the spacer 42. Note that the first substrate 40 and the second substrate 50 may be arranged by different support bosses 34 having different outer diameters. Also in this case, the spacer 42 is not required.

[0040] When the sensor module 100 includes the second substrate 50, the first substrate 40 and the second substrate 50 can be fixed to the cap 3 by using at least one support boss 34 and a spacer 42 for keeping the distance between the opposing plate surfaces of the first substrate 40 and the second substrate 50 constant (see FIG. 4). Further, the first substrate 40 is fixed to the cap 3 by using at least one support boss 34, and the second substrate 50 may be fixed to the cap 3 by using other support bosses (not shown). Furthermore, both the first substrate 40 and the second substrate 50 may be fixed to the cap 3 by any other method. "Fixed to the cap 3" means both the case of being directly fixed to the cap 3 and the case of being indirectly fixed to the cap 3 via other members. Also, the support boss 34 and / or other support bosses may be integrally formed with the cap 3, may be integrally formed with the lens portion 32, or may be separate bodies.

[0041] The transmission / reception IC 21 (having a transmission antenna and a reception antenna not shown) mounted on the first substrate 40 is covered by the support wall 33. Here, being covered by the support wall 33 means the case where, as shown in FIG. 4, the support wall 33 and the first substrate 40 are in contact with each other and the transmission / reception IC 21 is completely housed inside the support wall 33. However, it also includes the case where there is a gap between the support wall 33 and the first substrate 40. In this case, at least a part of the transmission / reception IC 21, the transmission antenna not shown, and the reception antenna not shown is visible from the gap between the support wall 33 and the first substrate 40.

[0042] The side wall 36 is disposed between the lens portion 32 and the support wall 33 and has a cylindrical shape. That is, the side wall 36 is disposed outside the diameter of the lens portion 32 and inside the diameter of the support wall 33. In other words, the side wall 36 stands in the same direction as the support wall 33 around the lens portion 32. The side wall 36 stands so as to protrude from the bottom wall 31 toward the direction of the transceiver IC 21. In the present embodiment, the protruding end portion 36a of the side wall 36 contacts the first substrate 40 or is located in the vicinity thereof (see FIG. 4). Thereby, the side wall 36 substantially completely overlaps with the transceiver IC 21 when viewed along the radial direction. That is, substantially the entire transceiver IC 21 is located in the radially inner space 36b of the side wall 36.

[0043] The housing 10 is made of resin or metal and has a bottomed cylindrical shape with an inner diameter larger than the outer diameter of the lid portion 3a of the cap 3. A male screw 10b is formed on the outer peripheral surface of the second peripheral wall 10a of the housing 10. In a state where the sensor assembly 70 is fixed to the cap 3, the male screw 10b of the housing 10 and the female screw 3e of the cap 3 are screwed together. An annular seal 15 is disposed at the boundary between the second peripheral wall 10a of the housing 10 and the first peripheral wall 3d of the fixing portion 3b of the cap 3 (see FIG. 4). Thereby, the first space 11 (an example of a closed space) that is closed by the cap 3 and the housing 10 and houses the sensor assembly 70 can be maintained in a watertight state. Further, the engagement between the housing 10 and the cap 3 is not limited to screwing, and any appropriate method such as fixing with screws, snap fit, welding, adhesion, etc. can be adopted.

[0044] In the case of engagement such as fixing with screws other than screwing, snap fit, welding, adhesion, etc., the effect is that when opening the opening 2 of the tank body 1b, the tightening between the lid portion 3a and the opening 2 is loosened, but at that time, it is possible to prevent accidentally loosening the tightening between the cap 3 and the housing 10. Thereby, it is possible to prevent the housing 10 from being removed more easily than the cap 3 and dust, water droplets, foreign matters, etc. from entering the inside.

[0045] In addition, as for the fixing by screws and the effect of snap fit, since the housing 10 and the cap 3 can be detached in the same way as screwing, when the sensor unit 20 fails or when replacing the battery 62a of the power supply unit 60, the housing 10 can be removed from the cap 3 to repair, replace the sensor unit 20, replace the battery 62a, etc.

[0046] Furthermore, in the case of fixing by screws, by using an O-ring or the like, the waterproof effect of the first space 11 can be improved by the fastening force and compressive force of the screws. Also, with a structure in which the screw is inserted from the side of the cap 3 into the housing 10 side and tightened, and locked and fixed in a state where the lid portion 3a of the sensor module 100 and the opening 2 of the tank main body 1b are tightened, the screws for fixing the housing 10 and the cap 3 are hidden and it becomes impossible to easily remove the screws. Since the housing 10 cannot be easily detached from the cap 3, it is possible to prevent the housing 10 from being removed for mischievous purposes. As a method of locking and fixing, for example, when the lid portion 3a is tightened to the opening 2 of the tank main body 1b as much as possible, overlapping ring shapes are provided on each of the sensor module 100 side and the fuel tank 1 side, and using the holes of the rings, structures such as locking and fixing with a padlock, etc. are conceivable.

[0047] The female screw 3e of the fixing portion 3b of the cap 3 and the male screw 10b of the second peripheral wall 10a of the housing 10 may be reversed. Specifically, an external thread is formed on the outer peripheral surface of the first peripheral wall 3d of the fixing portion 3b, and an internal thread is formed on the second peripheral wall 10a of the housing 10, and the external thread and the internal thread are screwed together. At this time, an annular seal 15 is disposed at the boundary between the second peripheral wall 10a of the housing 10 and the first peripheral wall 3d of the fixing portion 3b. Even with such a structure, it is possible to maintain the first space 11, which is closed by the cap 3 and the housing 10 and houses the sensor assembly 70, in a watertight state. The seal 15 for maintaining the watertight state may be an O-ring, a caulking agent, a water repellent material may be applied to the screwed portion, or other methods may be used. In FIGS. 2 and 3, the illustration of the seal 15 is omitted.

[0048] 〔Operation of Sensor Module〕 Next, the detection of the remaining amount of kerosene 5 and the like using the sensor module 100 will be described with reference to FIG. 4. The sensor module 100 disposed outside the fuel tank 1 transmits, at predetermined intervals (for example, every 10 minutes), a transmission pulse signal generated by the transmission / reception IC 21 mounted on the first substrate 40, which is modulated and transmitted as radio waves from a transmission antenna (not shown) of the transmission / reception IC 21 toward the internal space 1a of the fuel tank 1. The transmission antenna transmits millimeter-wave radio waves that pass through the resin lens portion 32 formed in the cap 3 and are reflected by the kerosene 5. The radio waves are, for example, electromagnetic pulses.

[0049] The radio waves transmitted from the transmission antenna and incident on the internal space 1a of the fuel tank 1 are reflected by the liquid surface 5a of the kerosene 5 and become reflected waves that travel toward the sensor module 100. The reflected waves pass through the cap 3 and the lens portion 32 and are received by a reception antenna (not shown).

[0050] When radio waves are transmitted from the transmission antenna, it is ideal for all the transmitted radio waves to travel toward the internal space 1a of the fuel tank 1. However, some radio waves may be transmitted not toward the internal space 1a but laterally, that is, in the direction of the support wall 33 or the like. Hereinafter, the radio waves transmitted in the direction toward the internal space 1a are also referred to as the main lobe, and the radio waves transmitted in directions other than the direction toward the internal space 1a are also referred to as the side lobe.

[0051] If the radio waves transmitted from the transmission antenna have not only the main lobe but also side lobes, when receiving the radio waves reflected by the surface of the kerosene 5 stored in the fuel tank 1 with the reception antenna, the side lobes may have an adverse effect and the detection accuracy of the remaining amount of kerosene 5 and the like may decrease. However, in the present embodiment, a cylindrical side wall 36 is formed around the lens portion 32 of the cap 3. Therefore, dielectric loss, reflection, refraction, etc. occur in the side wall 36 with respect to the side lobes radiated laterally from the transmission antenna, and the side lobes passing through the side wall 36 are reduced. As a result, it is possible to reduce the side lobes that have an adverse effect on the reflected waves and suppress a decrease in the detection accuracy of the remaining amount of kerosene 5 and the like.

[0052] The reflected wave (electromagnetic pulse) received by the receiving antenna is demodulated into a received pulse signal and then input to the arithmetic IC 22. The arithmetic IC 22 measures the time from when the electromagnetic pulse is transmitted from the transmitting antenna until the reflected wave is received by the receiving antenna (hereinafter also referred to as the propagation time), and based on the propagation time, calculates the remaining amount of kerosene 5 in the internal space 1a of the fuel tank 1 and the like. The arithmetic IC 22 stores in advance the propagation time (hereinafter also referred to as the full amount propagation time) when the kerosene 5 is sufficiently stored up to the upper limit amount (hereinafter also referred to as the full amount) in the internal space 1a of the fuel tank 1, and calculates the remaining amount of kerosene 5 and the like from the ratio or difference between the full amount propagation time and the propagation time. The calculation of the remaining amount and the like may be configured to store the propagation time when the kerosene 5 is in an empty state or a 50% state regardless of the comparison between the full propagation time and the propagation time, and calculate the remaining amount and the like based on this.

[0053] The arithmetic IC 22 calculates the distance to the liquid level 5a for calculating the remaining amount of kerosene 5 in the fuel tank 1, for example, every 10 minutes. When the remaining amount becomes, for example, 50% or less of the full amount (hereinafter also referred to as a predetermined amount or less), it outputs a signal indicating the remaining amount of kerosene 5 and the like. The signal output from the arithmetic IC 22 is input to the external communication IC 90 via the connection member 80. When a signal indicating the remaining amount of kerosene 5 and the like is input from the arithmetic IC 22, the external communication IC 90 transmits a radio signal including the remaining amount of the kerosene 5 and the like and the unique number representing the fuel tank 1 from the external communication antenna 91 toward the outside of the sensor module 100. The fuel sales store or management company that receives the radio signal grasps the remaining amount of kerosene 5 in the fuel tank 1. When the received radio signal is information for calculating the remaining amount, the remaining amount of kerosene 5 can be grasped by calculating the remaining amount of kerosene 5 in the system (not shown) of the fuel sales store or management company based on this information. Note that the signal output from the arithmetic IC 22 or the radio signal transmitted from the external communication IC 90 may be the ratio of the remaining amount and the like to the full amount of kerosene 5 instead of the remaining amount of kerosene 5 and the like.

[0054] In this way, by using the sensor module 100 in the fuel tank 1, fuel vendors and management companies can receive the radio signals transmitted from the external communication antenna 91 at the store or company when the kerosene 5 in the fuel tank 1 reaches or falls below a predetermined amount, and thereby grasp the remaining amount of kerosene 5 every 10 minutes. As a result, it is no longer necessary for fuel vendors and management companies to visit the location where the fuel tank 1 is installed to measure the remaining amount of kerosene 5. Fuel vendors and management companies that have grasped that the remaining amount of kerosene 5 in the fuel tank 1 is below the predetermined amount can appropriately replenish the kerosene 5 into the fuel tank 1. Also, since the owner of the fuel tank 1 can receive the radio signals transmitted from the external communication antenna 91 at home and grasp the remaining amount of kerosene 5 every 10 minutes, the owner can request the fuel vendor or management company to replenish the kerosene 5 when the remaining amount of kerosene 5 in the fuel tank 1 reaches or falls below the predetermined amount.

[0055] 〔Effect of the sensor module〕 In the sensor module 100 of the present embodiment, the side wall 36 is arranged around the lens portion 32 of the cap 3. Therefore, dielectric loss, reflection, refraction, etc. occur in the side wall 36 with respect to the side lobe radiated laterally from the transmitting antenna, and the side lobe passing through the side wall 36 decreases. As a result, it is possible to reduce the side lobe that adversely affects the reflected wave reflected by the liquid surface 5a of the kerosene 5 and suppress a decrease in the detection accuracy of the remaining amount of the kerosene 5 and the like.

[0056] Fig. 5 shows the electromagnetic field simulation result of the radio wave transmitted from the transmitting antenna of the transmitting unit 21a when there is no side wall 36. Fig. 6 shows the electromagnetic field simulation result of the radio wave transmitted from the transmitting antenna of the transmitting unit 21a when there is a side wall 36. In Figs. 5 and 6, the darker the illustrated color, the greater the intensity of the electromagnetic field, and the portion surrounded by the ellipse indicates the intensity of the electromagnetic field of the side lobe. It can be seen from Figs. 5 and 6 that the side lobe decreases more when there is a side wall 36 than when there is no side wall 36.

[0057] According to the sensor module 100 of this embodiment, since the sensor module 100 is arranged outside the fuel tank 1, there is no need to modify the fuel tank 1 in order to arrange the sensor module 100 in the existing fuel tank 1, and the remaining amount of the kerosene 5 contained in the fuel tank 1 as it is can be calculated. Further, since the remaining amount of the kerosene 5 is calculated using radio waves, it can be easily detected (calculated) at set time intervals of the remaining amount of the kerosene 5. Furthermore, since the remaining amount of the kerosene 5 is calculated by calculating the time until the radio wave is directly reflected by the kerosene 5 and received, the remaining amount of the kerosene 5 can be detected with high resolution by one sensor module 100.

[0058] In the cap 3 of the sensor module 100 of this embodiment, since the lid portion 3a, the fixing portion 3b, the lens portion 32, the support wall 33, and the side wall 36 are integrally formed by supplying molten resin to a molding die and curing it, compared with the case of manufacturing and assembling them individually, the cap 3 can be manufactured with low man-hours and low cost. Further, a cap 3 with high positional accuracy of the lid portion 3a, the fixing portion 3b, the lens portion 32, the support wall 33, and the side wall 36 can be obtained.

[0059] According to the sensor module 100 of this embodiment, since the annular seal 15 is arranged at the boundary between the second peripheral wall 10a of the housing 10 and the first peripheral wall 3d of the fixing portion 3b of the cap 3, even when the sensor module 100 is arranged outdoors, the first space 11 is maintained in a watertight state and rainwater does not enter the first space 11.

[0060] According to the sensor module 100 of this embodiment, the remaining amount of the kerosene 5 can be known at a location away from the fuel tank 1 without visually checking the inside of the fuel tank 1.

[0061] According to the sensor module 100 of this embodiment, by using millimeter waves as the radio wave, the radio wave can penetrate the resin. Therefore, in the resin cap 3 of the fuel tank 1, even if the sensor module 100 is arranged outside the cap 3, the remaining amount of kerosene 5 in the fuel tank 1 can be calculated through the cap 3. If the radio wave is light such as infrared rays or visible light, in order for the radio wave to pass through the cap 3, part or all of the cap 3 must be formed of a transparent or translucent resin or holes must be made in the cap 3. However, by using millimeter waves as the radio wave, the cap 3 does not need to use a transparent or translucent material or make holes, and may be formed of a colored insulating material that does not transmit the light used in the existing cap 3, and there is no need to make holes to impair the watertightness. The transparency and transmittance of transparent and translucent materials deteriorate when the transparency decreases due to changes over time. If the cap 3 is made of metal, by replacing it with a resin cap 3 sold by the manufacturer of the fuel tank 1 as a special product, the remaining amount of kerosene 5 in the fuel tank 1 can be calculated through the cap 3. Therefore, the reliability in terms of safety of the mounting state of the cap 3 to the opening 2 is guaranteed by the manufacturer of the fuel tank 1. Therefore, the reliability of the conventional function of the fuel tank 1 is not impaired.

[0062] 〔Other Embodiments〕 (1) In the above embodiment, the support wall 33 and the side wall 36 of the sensor module 100 are cylindrical, but it is not limited thereto. It is only necessary that a curved or linear wall is formed around the lens portion 32, and it may be a single body or may be formed in a structure connected to a plurality of curved and / or linear shapes. Further, the cylindrical side wall 36 may be formed double or triple around the lens portion 32. The side wall 36 can be configured in any shape and any number as long as it can reduce the side lobes that adversely affect the reflected wave of the radio wave reflected by the liquid surface 5a of the kerosene 5.

[0063] (2) In the above embodiment, the side wall 36 of the sensor module 100 was made of resin integrally formed with the cap 3, but the side wall 36 may be made of a material other than resin, such as metal. As long as it is possible to reduce the side lobes that adversely affect the reflected wave of the radio wave reflected by the liquid surface 5a of the kerosene 5, the side wall 36 can be made of any material. At this time, for example, if the side wall 36 is made of metal, the metal side wall 36 can be joined to the cap 3 simultaneously with the resin molding of the cap 3 by performing insert molding.

[0064] (3) In the above embodiment, the side wall 36 was configured such that the protruding end portion 36a contacts or is located in the vicinity of the first substrate 40. As a result, when viewed along the radial direction, the side wall 36 almost completely overlapped with the transceiver IC 21. However, the present invention is not limited to this configuration. The side wall 36 may be configured to have a height such that the protruding end portion 36a is separated from the first substrate 40. At this time, when viewed along the radial direction, the side wall 36 may be configured to have a height such that at least a part of the side wall 36 overlaps with the transceiver IC 21, or the side wall 36 may be configured to have a height such that the side wall 36 and the transceiver IC 21 do not overlap at all. That is, at least a part of the transceiver IC 21 may be located in the radially inner space 36b of the side wall 36, or the transceiver IC 21 may not be located in the radially inner space 36b of the side wall 36. As long as it is possible to reduce the side lobes that adversely affect the reflected wave of the radio wave reflected by the liquid surface 5a of the kerosene 5, the side wall 36 can be set to any height.

[0065] (4) In the above embodiment, the side wall 36 of the sensor module 100 stands upright from the bottom wall 31 of the cap 3 toward the transceiver IC 21, but the present invention is not limited to this. Instead of or together with the side wall 36 extending from the bottom wall 31 toward the transceiver IC 21, the side wall 36 may extend from the bottom wall 31 in the direction opposite to the transceiver IC 21, that is, toward the inner space 1a of the fuel tank 1. As long as it is possible to reduce the side lobes that adversely affect the reflected wave of the radio wave reflected by the liquid surface 5a of the kerosene 5, the side wall 36 can be arranged at any position.

[0066] (5) In the above embodiment, the side wall 36 was disposed between the lens portion 32 and the support wall 33, but it is not limited thereto. The side wall 36 may be disposed radially outside the support wall 33. Even in this case, it is preferable that the side wall 36 stands in the same direction as the support wall 33 around the lens portion 32.

[0067] (6) In the above embodiment, the resin material of the cap 3 was not specified, but for example, it may be a PBT (Poly Butylene Terephthalate) resin containing a glass filler. By using a resin material containing a glass filler, the cap 3 can be formed with high strength. Also, for example, the resin material of the cap 3 may have a relative dielectric constant of 3 or more. By using a resin material having a relative dielectric constant of 3 or more for the cap 3 including the side wall 36, it is possible to reduce the side lobe that adversely affects the reflected wave of the radio wave reflected by the liquid surface 5a of the kerosene 5.

[0068] (7) In the above embodiment, the transmission / reception IC 21 and the arithmetic IC 22 were mounted on the first substrate 40, and the external communication IC 90 was mounted on the second substrate 50, but each IC can be mounted on an arbitrary substrate.

[0069] (8) In the above embodiment, the sensor assembly 70 was composed of the first substrate 40 and the second substrate 50, but it may be composed of one substrate, or may be composed of three or more substrates.

[0070] (9) In each of the above embodiments, the sensor module 100 was configured to operate by the battery 62a, but it may be configured to operate by a commercial power supply.

[0071] In the above-described embodiment, after the remaining amount of kerosene 5 has reached 50% or less, the remaining amount of kerosene 5 and the like have been transmitted by radio signal every 10 minutes, but it is not limited thereto. For example, after the remaining amount of kerosene 5 has reached 50% or less, a radio signal may be transmitted every time the remaining amount reaches 40%, 30%, or 20%, that is, every time the kerosene 5 decreases by 10%. Further, after the remaining amount of kerosene 5 has reached 20% or less, for example, a radio signal may be transmitted every time the kerosene 5 decreases by 3%. In this way, by increasing the transmission frequency of the radio signal as the fuel tank 1 approaches empty, it is possible to also serve as an alert that the fuel tank 1 is about to become empty.

Industrial Applicability

[0072] The present disclosure can be used for a sensor module.

Explanation of Signs

[0073] 1: Fuel tank (container) 1a: Internal space 2: Opening 3: Cap 3a: Lid portion 5: Kerosene (contents) 10: Housing 11: First space (closed space) 20: Sensor unit 21: Transceiver IC (transceiving unit) 21a: Transmitting unit 21b: Receiving unit 22: Arithmetic IC (arithmetic unit) 32: Lens unit 33: Support wall 36: Side wall 60: Power supply unit 90: External communication IC (external communication unit) 100: Sensor module

Claims

1. A sensor module attached to an opening of a container containing contents, comprising a cap and a sensor unit, wherein the cap has a lid portion that closes the opening, a lens portion, a support wall that stands around the lens portion and supports the sensor unit, and a side wall, the sensor unit has a transceiver unit including a transmitter that transmits radio waves and a receiver that receives the radio waves, the lens portion is arranged to face the transceiver unit of the sensor unit, the transmitter transmits the radio waves that pass through the lens portion and reach the internal space of the container, the receiver receives a reflected wave after the radio waves are reflected by the contents in the internal space, and the side wall is a sensor module that stands around the lens portion and is arranged in the same direction as the support wall.

2. The sensor module according to claim 1, wherein the sensor unit further has an arithmetic unit that calculates the remaining amount of the contents or information for calculating the remaining amount based on the time from when the transmitter transmits the radio waves until the receiver receives the reflected wave.

3. Further comprising an external communication unit, wherein the external communication unit wirelessly transmits a signal indicating the remaining amount of the contents or the information for calculating the remaining amount calculated by the arithmetic unit to the outside.

4. Further comprising a power supply unit, wherein the power supply unit supplies power to the sensor unit and the external communication unit.

5. Further comprising a housing configured to be detachable from the cap, wherein the sensor unit is housed in a closed space formed by the cap and the housing.

6. The sensor module according to any one of claims 1 to 4, wherein the side wall is integrally formed with the lid portion.

7. The sensor module according to any one of claims 1 to 4, wherein the side wall has a cylindrical shape.

8. The sensor module according to any one of claims 1 to 4, wherein the radio waves transmitted by the transmitter are millimeter waves.

Images