Reed switch unit

Abstract

A reed switch unit (11) is provided with: an elongated reed switch subunit (21) having a reed switch (25) and having a first end (26) and a second end (27) in the longitudinal direction; and a cylindrical housing (22) having a first opening (32) into which the reed switch subunit (21) can be inserted from the first end (26) side, the housing (22) housing and holding the reed switch subunit (21). The second end portion (27) side of the reed switch subunit (21) is supported by the housing (22) on the first opening portion (32) side. The housing (22) has a second opening (33) on the opposite side of the first opening (32). The reed switch unit (11) is provided with a rubber member (23) that supports the first end portion (26) of the reed switch subunit (21), and the rubber member (23) blocks water from the second opening portion (33) by being fitted into the second opening portion (33).

Description

Technical Field

[0001] The invention relates to a reed switch unit. Background Art

[0002] In the past, as a reed switch unit, there is a reed switch unit that is provided in a liquid storage tank (for example, refer to Patent Document 1). The reed switch unit includes a cylindrical housing that is integrally provided in the liquid storage tank, and an elongated reed switch subunit that is accommodated and retained in the housing. The reed switch subunit has a reed switch, and has a first end and a second end in the length direction. The reed switch subunit is inserted into the opening of the housing from the first end of the reed switch subunit in a horizontal direction, and the second end of the reed switch unit is supported by the housing on the opening side of the housing. A float is accommodated in the liquid storage tank, and the float has a permanent magnet and floats on the liquid. For example, when the permanent magnet of the float approaches the reed switch due to the up and down movement of the float according to the level of the liquid, the reed switch electrically connects two terminals. For example, a control unit connected to the two terminals can detect a reduction in liquid. Prior art literature Patent Literature

[0003] Patent Document 1: International Publication No. 2010 / 035907 Summary of the invention Problems to be solved by the invention

[0004] However, in the above-mentioned reed switch unit, although the second end of the reed switch subunit is supported by the housing on the opening side of the housing, the first end of the reed switch subunit is easy to shake in the housing. That is, since the first end of the reed switch subunit is inserted from the opening of the housing to the deep part of the housing, it is necessary to set a small clearance between the first end of the reed switch subunit and the housing in manufacturing. This clearance sometimes allows the first end to shake in the housing. This shaking, for example, becomes a cause of reducing the detection accuracy of the reed switch. For example, it becomes a cause of erroneous judgment that the control unit exceeds the threshold value in a state before the amount of liquid exceeds the threshold value.

[0005] An object of the present invention is to provide a reed switch unit capable of improving detection accuracy. Solutions to Solve Problems

[0006] The reed switch unit of the present invention includes: an elongated reed switch sub-unit having a reed switch and having a first end and a second end in the longitudinal direction; and a cylindrical housing having a first opening, the reed switch sub-unit can be inserted into the first opening from the first end side, the housing houses and holds the reed switch sub-unit, the second end side of the reed switch sub-unit is supported by the housing on the first opening side, the housing has a second opening on the side opposite to the first opening, the reed switch unit includes a rubber member, the rubber member seals the second opening by being fitted into the second opening, and supports the first end of the reed switch sub-unit. Effect of the Invention

[0007] According to the reed switch unit of the present invention, the detection accuracy can be improved. Description of the Drawings

[0008] Figure 1 It is a schematic side view of a liquid storage tank in one embodiment. Figure 2 It is a perspective view of a reed switch unit in one embodiment. Figure 3 It is an exploded perspective view of a reed switch unit in one embodiment. Figure 4 It is a top view of a reed switch sub-unit and a rubber member in one embodiment. Figure 5 It is a partial cross-sectional view of a reed switch unit in one embodiment. Figure 6 It is a partial cross-sectional view of a reed switch unit in one embodiment. Detailed Embodiment

[0009] [Description of Embodiment of the Present Invention] First, embodiments of the present invention will be listed and described. The reed switch unit of the present invention, [1] includes: an elongated reed switch sub-unit having a reed switch and having a first end and a second end in the longitudinal direction; and a cylindrical housing having a first opening, the reed switch sub-unit can be inserted into the first opening from the first end side, the housing houses and holds the reed switch sub-unit, the second end side of the reed switch sub-unit is supported by the housing on the first opening side, the housing has a second opening on the side opposite to the first opening, the reed switch unit includes a rubber member, the rubber member seals the second opening by being fitted into the second opening, and supports the first end of the reed switch sub-unit.

[0010] According to this structure, the second end side of the reed switch sub-unit is supported by the housing on the first opening side, and the first end is supported by the rubber member fitted into the second opening. Therefore, the shaking of the reed switch sub-unit and the reed switch relative to the housing can be suppressed. Thus, for example, the reed switch unit can detect changes in a magnetic field such as the approach of a permanent magnet with high precision. In addition, the second opening is waterproofed by the rubber member, so the ingress of water into the reed switch sub-unit can be prevented. Further, the rubber member has the function of supporting the first end of the reed switch sub-unit and the function of waterproofing the second opening as one member. Therefore, for example, an increase in the number of components can be suppressed.

[0011] [2] In the above [1], it may also be that the first end has a support convex portion protruding in the length direction of the reed switch sub-unit, the rubber member has a support concave portion, and the support convex portion is fitted into the support concave portion.

[0012] According to this structure, the first end has a support convex portion protruding in the length direction of the reed switch sub-unit, the rubber member has a support concave portion, and the support convex portion is fitted into the support concave portion. Therefore, the shaking of the first end in the direction crossing the length direction of the reed switch sub-unit is well suppressed.

[0013] [3] In the above [2], the support convex portion may also be cylindrical. According to this structure, since the support convex portion is cylindrical, the shaking of the first end in all directions crossing the length direction of the reed switch sub-unit is well suppressed. That is, since the support convex portion is cylindrical, it can be evenly supported by the support concave portion of the rubber member in all directions crossing the length direction of the reed switch sub-unit, so the shaking in all directions is well suppressed.

[0014] [4] In any one of the above [1] to the above [3], it may also be that the rubber member has a plurality of protruding portions that locally press-contact the second opening in the length direction of the reed switch sub-unit.

[0015] According to this structure, since the rubber member has a plurality of protruding portions that locally press-contact the second opening in the length direction of the reed switch sub-unit, the assemblability of the rubber member to the second opening becomes good, and the waterproof property of the second opening becomes good. That is, for example, if the rubber member has a shape that press-contacts with a single surface continuous with the second opening, the frictional resistance when fitted into the second opening becomes large, or the waterproof property may not be maintained due to deformation of a part, etc., but these can be avoided.

[0016] [5]In [4] above, it is also possible that, when viewed from the opening direction of the second opening portion, the second opening portion has a rectangular shape with a longer width direction than the height direction, and when viewed from the opening direction of the second opening portion, the rubber member has a rectangular shape with a longer width direction than the height direction, and the protruding portion is provided on both sides in the height direction of the rubber member and is provided over the entire width direction of the rubber member.

[0017] According to this structure, the protruding portion is provided on both sides in the height direction of the rubber member and is provided over the entire width direction that is longer than the height direction. Therefore, the assemblability of the rubber member to the second opening portion becomes better, and the water stoppage property of the second opening portion becomes better. That is, for example, compared with a structure in which the protruding portion is provided on both sides in the width direction of the rubber member and is provided over the entire height direction that is shorter than the width direction, better effects can be obtained.

[0018] [6]In any one of [1] to [5] above, it is also possible that a lid is provided, and the lid prevents the rubber member from falling off from the second opening portion. According to this structure, a lid is provided, and this lid prevents the rubber member from falling off from the second opening portion. Therefore, for example, it is possible to prevent the rubber member fitted into the second opening portion from falling off from the second opening portion due to vibration or the like.

[0019] [Details of the Embodiment of the Present Invention] Hereinafter, the reed switch unit 11 according to an embodiment of the present invention will be described with reference to the drawings. In each drawing, for convenience of explanation, a part of the structure may be exaggerated or simplified. Also, the dimensional ratios of the respective parts may be different in each drawing. In this specification, "parallel", "orthogonal", and "perfect circle" include not only the cases that are strictly parallel, orthogonal, or perfect circle, but also the cases that are substantially parallel, orthogonal, or perfect circle within the range of achieving the effects in this embodiment. In addition, the present invention is not limited to these examples, but is shown by the claims and is intended to include all modifications within the meaning equivalent to the claims and the scope.

[0020] (Structure of the Reed Switch Unit 11) As Figure 1 shown, the reed switch unit 11 is provided in a liquid storage tank 13 that can store a liquid 12 such as a coolant. The liquid storage tank 13 has a float 14 inside. The float 14 is configured to be able to move up and down along a rail 15 formed in the liquid storage tank 13 and floats on the liquid 12. In addition, the float 14 has a permanent magnet 16. In addition, the liquid storage tank 13 of the present embodiment has a unit holding portion 17 that holds the reed switch unit 11 at the lower part. The reed switch unit 11 is held by the unit holding portion 17. The reed switch unit 11 is used to detect the amount of the liquid 12 stored in the liquid storage tank 13 according to the position of the permanent magnet 16.

[0021] As Figure 2 and Figure 3 shown, the entire reed switch unit 11 is formed in an elongated shape. The reed switch unit 11 includes an elongated reed switch sub-unit 21, a cylindrical housing 22, a rubber member 23, and a cover 24.

[0022] (Structure of Reed Switch Sub-Unit 21) As Figure 3 and Figure 4 shown, the reed switch sub-unit 21 has a reed switch 25 and has a first end 26 and a second end 27 in the longitudinal direction.

[0023] For example, the reed switch 25 has a pair of ferromagnetic pieces housed in a glass tube, and the pair of ferromagnetic pieces switch between a connected state and a non-connected state (open state) according to a magnetic field. The reed switch 25 has a first switch terminal 25a and a second switch terminal 25b protruding outward from both ends of the glass tube.

[0024] In addition, the reed switch sub-unit 21 of the present embodiment has a first connector 28, a second connector 29, and a base portion 30. The first connector 28 and the second connector 29 are insert-molded in the resin base portion 30. The first connector 28 is connected to the first switch terminal 25a. The first connector 28 has a first external terminal 28a protruding and exposed outward from the second end 27 in the base portion 30. The second connector 29 is connected to the second switch terminal 25b. The second connector 29 has a second external terminal 29a protruding and exposed outward from the second end 27 in the base portion 30. The first external terminal 28a and the second external terminal 29a protrude in parallel.

[0025] In addition, as Figure 4 and Figure 5 shown, the first connector 28 has a first locking portion 28b protruding and exposed outward from the second end 27 side to the outside in the width direction of the base portion 30. In addition, the second connector 29 has a second locking portion 29b protruding and exposed outward from the second end 27 side to the outside in the width direction of the base portion 30. The first locking portion 28b and the second locking portion 29b protrude in opposite directions, that is, in directions away from each other, in the width direction of the base portion 30. The first locking portion 28b and the second locking portion 29b are formed in a claw shape such that the protruding amount increases toward the second end 27 side.

[0026] In addition, as Figure 4 shown, in the base portion 30, the first end 26 has a support convex portion 31 protruding in the longitudinal direction of the reed switch sub-unit 21. The support convex portion 31 of the present embodiment is formed in a cylindrical shape. The support convex portion 31 is provided at the center in the width direction of the base portion 30. In addition, the support convex portion 31 is provided at the center in the height direction of the base portion 30 (seeFigure 6 )。

[0027] (Structure of the housing 22) As Figure 3 shown, the housing 22 is formed in a rectangular tube shape capable of accommodating and holding the reed switch sub-unit 21. The housing 22 of the present embodiment is in a rectangular tube shape that is rectangular when viewed in the longitudinal direction of the housing 22. The housing 22 has a first opening 32, and the reed switch sub-unit 21 can be inserted into the first opening 32 from the first end 26 side. The first opening 32 is formed to be able to engage with an external connector electrically connected to a control unit (not shown). In addition, the housing 22 has a second opening 33 on the side opposite to the first opening 32. Further, the second opening 33 is formed in a rectangular shape whose width direction is longer than the height direction when viewed from the opening direction of the second opening 33.

[0028] As Figure 5 shown, in the housing 22, a support portion 34 is provided on the inner surface at a position near the first opening 32. The support portion 34 supports the second end 27 side of the reed switch sub-unit 21 in a state where the reed switch sub-unit 21 is inserted into the housing 22. For example, the support portion 34 supports the second end 27 side of the reed switch sub-unit 21 by being recessed by the first locking portion 28b and the second locking portion 29b in a state where the reed switch sub-unit 21 is inserted into the housing 22. Further, the support portion 34 is a wall surface that is set to be recessed by the first locking portion 28b and the second locking portion 29b when the reed switch sub-unit 21 is inserted into the housing 22. The support portion 34 is deformed in a manner of being shaved off by the first locking portion 28b and the second locking portion 29b when the reed switch sub-unit 21 is inserted into the housing 22. In addition, Figure 5 , a situation where the first locking portion 28b and the second locking portion 29b are recessed into the support portion 34 is schematically shown.

[0029] In addition, as Figure 3 shown, in the housing 22, a fixing portion 35 is provided on the outer surface at a position near the second opening 33. The fixing portion 35 is provided on both surfaces in the height direction of the housing 22. The fixing portion 35 of the present embodiment has: a locking protrusion 35a provided at the center in the width direction of the housing 22; and a pair of guide protrusions 35b provided at positions spaced apart from the locking protrusion 35a in the width direction of the housing 22. The locking protrusion 35a has an inclined surface 35c whose protruding amount increases as it protrudes toward the center side in the longitudinal direction of the housing 22. The pair of guide protrusions 35b protrude with a constant protruding amount and extend parallel to the longitudinal direction of the housing 22.

[0030] (Structure of the rubber member 23) As Figure 3 and Figure 6As shown, the rubber member 23 is formed in a rectangular parallelepiped shape. When viewed from the opening direction of the second opening portion 33, the rubber member 23 has a rectangular shape with a longer width direction than the height direction. The rubber member 23 seals the second opening portion 33 by being fitted into the second opening portion 33 and supports the first end portion 26 of the reed switch sub-unit 21. For example, the rubber member 23 has a support recess 36 into which the support protrusion 31 is fitted. The support recess 36 has a circular inner peripheral surface, and the entire outer peripheral surface of the cylindrical support protrusion 31 is in close contact with this inner peripheral surface.

[0031] In addition, the rubber member 23 has a plurality of protrusions 37 that are in partial pressing contact with the second opening portion 33 in the length direction of the reed switch sub-unit 21. For example, the protrusions 37 are provided on both surfaces in the height direction of the rubber member 23. In other words, the protrusions 37 protrude from both surfaces in the height direction of the rubber member 23. In addition, the protrusions 37 are provided over the entire width direction of the rubber member 23. In other words, the protrusions 37 protrude with a uniform height over the entire width direction of the rubber member 23. Three protrusions 37 are provided at equal intervals in the length direction of the rubber member 23. In addition, in the rubber member 23, since the protrusions 37 are not provided on both surfaces in the width direction, flat surfaces 23a that are continuous in the length direction of the rubber member 23 are formed.

[0032] (Structure of the cover 24) As Figure 3 and Figure 6 shown, the cover 24 prevents the rubber member 23 from falling off from the second opening portion 33 by being fixed to the second opening portion 33 side of the housing 22. For example, the cover 24 has a square plate-shaped plate portion 38 that covers the second opening portion 33, and a cylindrical portion 39 that extends in a cylindrical shape so as to cover the outer periphery of the housing 22 from the outer edge of the plate portion 38. The cylindrical portion 39 has a pair of slits 39a into which a pair of guide protrusions 35b are inserted, and a locking piece 39b that can be bent in the height direction between the pair of slits 39a. The locking piece 39b has a locking hole 39c into which the locking protrusion 35a is inserted. The cover 24 is assembled to the housing 22 by moving relative to the housing 22 along the length direction of the housing 22. When assembling the cover 24, first, the moving direction is guided by the guide protrusions 35b inserted into the slits 39a. Then, when assembling the cover 24, the locking piece 39b is bent to cross the inclined surface 35c of the locking protrusion 35a, and the locking protrusion 35a is inserted into the locking hole 39c, thereby completing the assembly. That is, the cover 24 is fixed to the housing 22 by the guide protrusions 35b being inserted into the slits 39a and the locking protrusions 35a being inserted into the locking holes 39c.

[0033] Next, the operation of the reed switch unit 11 configured as described above will be described. For example, when the liquid 12 stored in the liquid storage tank 13 decreases, the permanent magnet 16 moves downward together with the floating body 14. Then, when the permanent magnet 16 approaches the reed switch unit 11, the reed switch 25 switches to the connected state. Thus, the decrease in the liquid 12 is detected by a control unit (not shown) connected to the first external terminal 28a and the second external terminal 29a.

[0034] Next, the effects of the above-described embodiment will be described below. (1) The second end portion 27 side of the reed switch sub-unit 21 is supported by the housing 22 on the first opening portion 32 side, and the first end portion 26 is supported by the rubber member 23 fitted into the second opening portion 33. Therefore, the shaking of the reed switch sub-unit 21 and the reed switch 25 relative to the housing 22 can be suppressed. Thereby, for example, the reed switch unit 11 can detect changes in the magnetic field such as the approach of the permanent magnet 16 with high precision. For example, false determination by the control unit that the amount exceeds the threshold value can be suppressed in a state before the amount of the liquid 12 exceeds the threshold value. In addition, since the second opening portion 33 is waterproofed by the rubber member 23, the immersion of the reed switch sub-unit 21 can be prevented. Further, since the rubber member 23 has a function of supporting the first end portion 26 of the reed switch sub-unit 21 and a function of waterproofing the second opening portion 33 with one member, for example, an increase in the number of components can be suppressed.

[0035] (2) The first end portion 26 has a support convex portion 31 protruding in the length direction of the reed switch sub-unit 21, and the rubber member 23 has a support concave portion 36 into which the support convex portion 31 is fitted. Therefore, the shaking of the first end portion 26 in the direction crossing the length direction of the reed switch sub-unit 21 is well suppressed.

[0036] (3) Since the support convex portion 31 has a cylindrical shape, the shaking of the first end portion 26 in all directions crossing the length direction of the reed switch sub-unit 21 is well suppressed. That is, since the support convex portion 31 has a cylindrical shape, it can be supported equally in all directions crossing the length direction of the reed switch sub-unit 21 by the support concave portion 36 of the rubber member 23, so the shaking in all directions is well suppressed.

[0037] (4) The rubber member 23 has a plurality of protruding portions 37 that are in partial pressing contact with the second opening 33 in the longitudinal direction of the reed switch sub-unit 21. Therefore, the assemblability of the rubber member 23 to the second opening 33 is improved, and the water tightness of the second opening 33 is improved. That is, for example, if the rubber member 23 does not have the protruding portions 37 and is in a shape of pressing contact with a continuous surface of the second opening 33, the frictional resistance when being fitted into the second opening 33 becomes large, but this situation can be avoided. Additionally, for example, if the rubber member 23 does not have the protruding portions 37 and is in a shape of pressing contact with a continuous surface of the second opening 33, it may not be able to maintain water tightness due to deformation of a part, etc., but this situation can be avoided.

[0038] (5) The protruding portions 37 are provided on both surfaces in the height direction of the rubber member 23 and are provided on the entire width direction that is longer than the height direction. Therefore, the assemblability of the rubber member 23 to the second opening 33 is further improved, and the water tightness of the second opening 33 is further improved. That is, for example, compared with a structure in which the protruding portions 37 are provided on both surfaces in the width direction of the rubber member 23 and are provided on the entire height direction that is shorter than the width direction, a better effect can be obtained.

[0039] (6) A cover 24 is provided, and the cover 24 prevents the rubber member 23 from falling off from the second opening 33. Therefore, for example, it can prevent the rubber member 23 fitted into the second opening 33 from falling off from the second opening 33 due to vibration or the like.

[0040] This embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented by combining them with each other within a range where there is no technical contradiction. · In the above embodiment, the first end portion 26 has a support convex portion 31, and the rubber member 23 has a support concave portion 36, and the support convex portion 31 is fitted into the support concave portion 36. However, this is not limited thereto. As long as the rubber member 23 can support the first end portion 26, it can also be changed to other structures. For example, it can also be configured to not have the support convex portion 31 and the support concave portion 36, and by pressing and contacting the first end portion 26 with the rubber member 23, the first end portion 26 is supported by frictional force.

[0041] · In the above embodiment, the support convex portion 31 has a cylindrical shape, but this is not limited thereto, and it can also be changed to other shapes. For example, the support convex portion 31 can also be a quadrangular prism shape. In addition, of course, in the shape of the support concave portion 36, it can also be changed according to the shape of the support convex portion 31.

[0042] · In the above embodiment, the rubber member 23 has a plurality of protruding portions 37 that are in partial pressing contact with the second opening 33, but this is not limited thereto, and it can also be configured to not have the protruding portions 37.

[0043] ·In the above-described embodiment, the protrusions 37 are provided on both surfaces of the rubber member 23 in the height direction, but it is not limited thereto. For example, they may be provided only on one surface of the rubber member 23 in the height direction. Additionally, for example, the protrusions 37 may be provided on both surfaces in the width direction or only on one surface in the width direction. Further, the protrusions 37 may be provided on both surfaces of the rubber member 23 in the height direction and both surfaces in the width direction.

[0044] ·In the above-described embodiment, the protrusions 37 are provided over the entire width direction, but it is not limited thereto. For example, they may be provided at both side positions in the width direction or only at the central position in the width direction.

[0045] ·In the above-described embodiment, three protrusions 37 are provided at equal intervals in the length direction of the rubber member 23, but it is not limited thereto. For example, they may be provided at unequal intervals or two or more than four may be provided.

[0046] ·In the above-described embodiment, the reed switch unit 11 includes a cover 24 that prevents the rubber member 23 from falling off from the second opening 33, but it is not limited thereto. It may not include the cover 24. In addition, in this case, for example, it is preferable to provide protrusions or the like on the housing 22 that suppress the falling off of the rubber member 23. In this way, for example, the number of components of the reed switch unit 11 can be reduced.

[0047] ·In the above-described embodiment, the second end portion 27 side of the reed switch sub-unit 21 is supported by being recessed into the support portion 34 through the first locking portion 28b and the second locking portion 29b, but the second end portion 27 side may also be supported by other structures.

[0048] ·In the above-described embodiment, the housing 22 is formed in a rectangular tube shape, but it is not limited thereto. As long as it can accommodate and hold the reed switch sub-unit 21, it may be changed to other shapes. For example, the housing 22 may be changed to a cylindrical shape.

[0049] ·In the above-described embodiment, the cover 24 is fixed to the housing 22 by inserting the guide protrusion 35b into the slit 39a and inserting the locking protrusion 35a into the locking hole 39c, but it is not limited thereto. It may also be fixed to the housing 22 by other structures. For example, the cover 24 may be fixed to the housing 22 using screws or the like.

[0050] ·In the above-described embodiment, the housing 22 is a dedicated component included in the reed switch unit 11, but it is not limited thereto. For example, it may also be an integrally formed product with the liquid storage tank 13.

[0051] ·In the above-described embodiment, the reed switch unit 11 is used to detect the amount of the liquid 12 stored in the liquid storage tank 13, but it is not limited thereto. It may also be used in other devices.

[0052] · The rubber member 23 of the illustrated embodiment is an elastic element that directly contacts the distal end of the housing 22 and the base portion 30. For example, when the reed switch unit 11 and / or the liquid storage tank 13 is subjected to external vibration, the rubber member 23 can at least partially, preferably completely absorb or attenuate the external vibration. Therefore, the rubber member 23 is beneficial to suppressing the vibration or displacement of the distal end of the base portion 30 and the reed switch 25 relative to the housing 22. As Figure 6 shown, by the rubber member 23, a gap can be formed between the radially outer surface of the base portion 30 and the radially inner surface of the housing 22 on the distal side of the base portion 30, and on the distal side of the base portion 30, the base portion 30 can be held in non-contact with the housing 22.

[0053] · The liquid storage tank 13 of the illustrated embodiment is sometimes referred to as a liquid tank. The liquid storage tank 13 can also be, for example, a vehicle liquid tank and can be used together with vibration sources such as an engine, an electric motor, and a traveling tire. The assembly of the floating body 14 and the permanent magnet 16 of the illustrated embodiment is sometimes referred to as a magnetic floating body. The reed switch unit 11 of the illustrated embodiment is sometimes referred to as a reed switch type liquid level sensor used together with a liquid tank and a magnetic floating body. The first external terminal 28a and the second external terminal 29a of the reed switch sub-unit 21 of the illustrated embodiment are sometimes referred to as electrical connector terminals. The second end portion 27 of the reed switch sub-unit 21 of the illustrated embodiment is sometimes referred to as the proximal end of the base portion 30. The first end portion 26 of the reed switch sub-unit 21 of the illustrated embodiment is sometimes referred to as the distal end of the base portion 30. The sub-equipment of the housing 22, the rubber member 23, and the cover 24 of the illustrated embodiment is sometimes referred to as an accessory configured to be retrofitted to a liquid tank. The housing 22 of the illustrated embodiment is sometimes referred to as a straight tube housing for housing the base portion 30 and the reed switch 25 or as a straight tube portion of an accessory. The rubber member 23 of the illustrated embodiment is sometimes referred to as a distal elastic plug, which is retrofitted to the radially inner side of the distal tubular portion of the housing 22 from the distal side of the housing 22 and is configured to position the distal end of the base portion 30 relative to the housing 22 in the longitudinal direction and the radial direction by directly contacting the housing 22 and the distal end of the base portion 30. The cover 24 of the illustrated embodiment is sometimes referred to as a distal cap, which is retrofitted to the radially outer side of the distal tubular portion of the housing 22 from the distal side of the housing 22 so as to cover the distal rubber plug (23).

[0054] · One aspect of the present invention is directed to a reed switch type liquid level sensor used together with a liquid tank and a magnetic floating body, the reed switch type liquid level sensor capable of comprising: An elongated base portion having a proximal end and a distal end including electrical connector terminals; A linear reed switch is fixedly supported on the elongated base portion so as to extend between the proximal end and the distal end of the elongated base portion; and An accessory includes a straight tube portion that houses the elongated base portion and the reed switch, and is configured to be retrofitted to the liquid tank, The straight tube portion of the accessory can have a proximal tubular portion including a proximal opening that covers the proximal end of the elongated base portion; and a distal tubular portion including a distal opening that covers the distal end of the elongated base portion, The accessory can include a distal elastic plug, The distal elastic plug is retrofitted to the radially inner side of the distal tubular portion of the straight tube portion from the distal side of the straight tube portion, and is configured to position the distal end of the elongated base portion relative to the straight tube portion in the length direction and the radial direction by directly contacting the distal tubular portion of the straight tube portion and the distal end of the elongated base portion.

[0055] · The accessory can include a distal cap that is retrofitted to the radially outer side of the distal tubular portion of the straight tube portion from the distal side of the straight tube portion so as to cover the distal elastic plug. Description of Reference Numerals

[0056] 11 Reed switch unit 12 Liquid 13 Liquid storage tank 14 Floating body 15 Rail 16 Permanent magnet 17 Unit holding portion 21 Reed switch sub-unit 22 Housing 23 Rubber member 23a Flat surface 24 Cover 25 Reed switch 25a First switch terminal 25b Second switch terminal 26 First end 27 Second end 28 First joint 28a First external terminal 28b First locking portion 29 Second joint 29a Second external terminal 29b Second locking portion 30 Base portion 31 Support convex portion 32 First opening 33 Second opening 34 Support part 35 Fixing part 35a Locking projection 35b Guide projection 35c Inclined surface 36 Support recess 37 Protrusion 38 Plate part 39 Cylindrical part 39a Slit 39b Locking piece 39c Locking hole

Claims

1. A reed switch unit, comprising: An elongated reed switch sub-unit having a reed switch and having a first end and a second end in the longitudinal direction; and A cylindrical housing having a first opening, into which the reed switch sub-unit can be inserted from the first end side, and the housing houses and holds the reed switch sub-unit, The second end side of the reed switch sub-unit is supported by the housing on the first opening side, The housing has a second opening on the side opposite to the first opening, The reed switch unit includes a rubber member that seals the second opening by being fitted into the second opening and supports the first end of the reed switch sub-unit.

2. The reed switch unit according to claim 1, wherein The first end has a support convex portion protruding in the longitudinal direction of the reed switch sub-unit, The rubber member has a support concave portion into which the support convex portion is inserted.

3. The reed switch unit according to claim 2, wherein The support convex portion is cylindrical in shape.

4. The reed switch unit according to claim 1, wherein The rubber member has a plurality of protrusions that are in partial pressing contact with the second opening in the longitudinal direction of the reed switch sub-unit.

5. The reed switch unit according to claim 4, wherein Viewed from the opening direction of the second opening, the second opening is rectangular in shape with a width direction longer than the height direction, Viewed from the opening direction of the second opening, the rubber member is rectangular in shape with a width direction longer than the height direction, The protrusions are provided on both sides in the height direction of the rubber member and are provided over the entire width direction of the rubber member.

6. The reed switch unit according to claim 1, wherein The reed switch unit includes a cover that prevents the rubber member from falling off from the second opening.

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