Reed Switch Unit

Abstract

To provide a reed switch unit capable of improving detection accuracy.SOLUTION: A reed switch unit 11 comprises: an elongate reed switch sub-unit 21, which has a reed switch 25 and has a first end portion 26 and a second end portion 27 in a length direction; and a cylindrical housing 22, which has a first opening portion 32 into which the reed switch sub-unit 21 can be inserted from the first end portion 26 side, and which accommodates and holds the reed switch sub-unit 21. The second end portion 27 side of the reed switch sub-unit 21 is supported on the first opening portion 32 side by the housing 22. The housing 22 has a second opening portion 33 on the opposite side to the first opening portion 32. The reed switch unit 11 is provided with a rubber member 23 that is fitted into the second opening portion 33 to stop water from the second opening portion 33, and that supports the first end portion 26 of the reed switch sub-unit 21.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a reed switch unit. [Background technology]

[0002] Conventionally, there is a reed switch unit that is provided in a reservoir tank (see, for example, Patent Document 1). This reed switch unit includes a cylindrical housing that is integrally provided with the reservoir tank and a long reed switch subunit that is accommodated and held in the housing. The reed switch subunit has a reed switch and has a first end and a second end in the longitudinal direction. The reed switch subunit is inserted horizontally into an opening of the housing from the first end side. The second end of the reed switch unit is supported by the housing on the opening side of the housing. A float that has a permanent magnet and floats in the liquid is accommodated in the reservoir tank. For example, when the permanent magnet of the float, which rises and falls with the liquid level, approaches the float, two terminals of the reed switch are electrically connected. This allows, for example, a control unit connected to the two terminals to detect a decrease in liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication (WO) No. 2010 / 035907 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the reed switch unit described above, although the second end of the reed switch subunit is supported by the housing on the opening side of the housing, the first end is prone to rattle within the housing. That is, because the first end is inserted deep into the housing, a slight clearance must be provided between the first end and the housing during manufacturing. Therefore, the first end is prone to rattle within the housing due to the clearance. This can, for example, reduce the detection accuracy of the reed switch. Specifically, it can cause erroneous determinations, such as the control unit determining that the amount of liquid has exceeded the threshold before it actually does so.

[0005] An object of the present disclosure is to provide a reed switch unit that can improve detection accuracy. [Means for solving the problem]

[0006] The reed switch unit of the present disclosure comprises a reed switch and a long reed switch subunit 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 subunit can be inserted from the first end side and accommodating and holding the reed switch subunit, wherein the reed switch subunit is a reed switch unit in which the second end side is supported by the housing on the first opening side, and the housing has a second opening on the opposite side of the first opening, and is provided with a rubber member that is fitted into the second opening to waterproof the second opening and supports the first end of the reed switch subunit. [Effects of the Invention]

[0007] The reed switch unit of the present disclosure can improve detection accuracy. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic side view of a reservoir tank according to one embodiment. [Figure 2] FIG. 2 is a perspective view of a reed switch unit according to one embodiment. [Figure 3] FIG. 3 is an exploded perspective view of a reed switch unit according to one embodiment. [Figure 4] FIG. 4 is a plan view of a reed switch subunit and a rubber member according to one embodiment. [Figure 5] FIG. 5 is a partial cross-sectional view of a reed switch unit according to one embodiment. [Figure 6] FIG. 6 is a partial cross-sectional view of a reed switch unit according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described. The reed switch unit of the present disclosure comprises: [1] A reed switch unit comprising: a long reed switch subunit having a reed switch and a first end and a second end in the longitudinal direction; and a cylindrical housing having a first opening into which the reed switch subunit can be inserted from the first end side and accommodating and holding the reed switch subunit, wherein the reed switch subunit is a reed switch unit in which the second end side is supported by the housing on the first opening side, and the housing has a second opening on the opposite side of the first opening, and is provided with a rubber member that is fitted into the second opening to waterproof the second opening and supports the first end of the reed switch subunit.

[0010] According to this configuration, the second end of the reed switch subunit is supported by the housing on the first opening side, and the first end is supported by a rubber member fitted into the second opening. This reduces rattle of the reed switch and the reed switch relative to the housing. This allows the reed switch unit to detect changes in a magnetic field, such as the approach of a permanent magnet, with high accuracy. Furthermore, the second opening is waterproofed by the rubber member, preventing the reed switch subunit from becoming wet. Furthermore, the rubber member functions to support the first end of the reed switch subunit and waterproof the second opening, all in one, thereby reducing the number of parts, for example.

[0011] [2] In the above [1], the first end may have a support protrusion that protrudes in the longitudinal direction of the reed switch subunit, and the rubber member may have a support recess into which the support protrusion fits.

[0012] According to this configuration, the first end has a support convex portion that protrudes in the longitudinal direction of the reed switch subunit, and the rubber member has a support concave portion into which the support convex portion fits, so that the first end is effectively prevented from rattling in a direction that intersects with the longitudinal direction of the reed switch subunit.

[0013] [3] In the above item [2], the supporting protrusion may be cylindrical. With this configuration, because the support protrusion is cylindrical, the first end is effectively prevented from rattling in all directions intersecting the longitudinal direction of the reed switch subunit. That is, because the support protrusion is cylindrical, it can be supported by the support recess of the rubber member evenly in all directions intersecting the longitudinal direction of the reed switch subunit, so rattling in all directions is effectively prevented.

[0014] [4] In any one of [1] to [3] above, the rubber member may have a plurality of protrusions in the longitudinal direction of the reed switch subunit that make localized pressing contact with the second opening.

[0015] According to this configuration, the rubber member has a plurality of protrusions in the longitudinal direction of the reed switch subunit that make localized pressure contact with the second opening, which improves the ease of assembly of the rubber member into the second opening and improves the watertightness of the second opening. That is, for example, if the rubber member is shaped to make pressure contact with the second opening on a single continuous surface, there is a risk that frictional resistance will increase when fitting the rubber member into the second opening, or that watertightness will be compromised due to partial distortion, but this can be avoided.

[0016] [5] In the above [4], the second opening may have a rectangular shape with a width longer than a height when viewed from the opening direction of the second opening, and the rubber member may have a rectangular shape with a width longer than a height when viewed from the opening direction of the second opening, and the protrusion may be provided on both sides of the rubber member in the height direction and across the entire width of the rubber member.

[0017] According to this configuration, the protruding portions are provided on both sides of the rubber member in the height direction and over the entire width direction, which is longer than the height direction, which improves the ease of assembly of the rubber member into the second opening and improves the watertightness of the second opening. That is, a better effect can be obtained compared to, for example, a configuration in which the protruding portions are provided on both sides of the rubber member in the width direction and over the entire height direction, which is shorter than the width direction.

[0018] [6] In any one of the above [1] to [5], a cover may be provided to prevent the rubber member from coming off the second opening. According to this configuration, a cover is provided that prevents the rubber member from coming off the second opening, so that, for example, the rubber member fitted into the second opening is prevented from coming off the second opening due to vibration or the like.

[0019] [Details of the embodiments of the present disclosure] Specific examples of the reed switch unit 11 of the present disclosure will be described below with reference to the drawings. For ease of explanation, some of the components may be exaggerated or simplified in the drawings. The dimensional ratios of the various components may differ between drawings. In this specification, "parallel," "orthogonal," and "circular" do not only refer to strictly parallel, orthogonal, or circular, but also include roughly parallel, orthogonal, or circular within the scope of the present embodiment. The present invention is not limited to these examples, but is defined by the claims, and all modifications within the meaning and scope of the claims are intended to be included.

[0020] (Configuration of reed switch unit 11) As shown in FIG. 1 , the reed switch unit 11 is provided in a reservoir tank 13 capable of storing a liquid 12 such as a coolant. The reservoir tank 13 has a float 14 therein. The float 14 is provided so as to be movable up and down, for example, along a rail 15 formed on the reservoir tank 13, and is configured to float in the liquid 12. The float 14 also has a permanent magnet 16. The reservoir tank 13 of this embodiment also has a unit holder 17 at its bottom that holds the reed switch unit 11. The reed switch unit 11 is held by the unit holder 17. The reed switch unit 11 is used to detect the amount of liquid 12 stored in the reservoir tank 13 according to the position of the permanent magnet 16.

[0021] 2 and 3, the reed switch unit 11 is formed in an elongated shape as a whole. The reed switch unit 11 includes an elongated reed switch subunit 21, a cylindrical housing 22, a rubber member 23, and a cover 24.

[0022] (Configuration of reed switch subunit 21) As shown in FIGS. 3 and 4, the reed switch subunit 21 has a reed switch 25 and has a first end 26 and a second end 27 in the length direction.

[0023] Specifically, the reed switch 25 is an electrical component that has a pair of ferromagnetic blades housed in a glass tube, and the pair of ferromagnetic blades are connected in response to a magnetic field. The reed switch 25 has a first switch terminal 25a and a second switch terminal 25b that protrude from both ends of the glass tube to the outside.

[0024] The reed switch subunit 21 of this embodiment also has a first terminal 28, a second terminal 29, and a base portion 30. The first terminal 28 and the second terminal 29 are insert-molded into the resin base portion 30. The first terminal 28 is connected to the first switch terminal 25a. The first terminal 28 has a first external terminal 28a that protrudes and is exposed to the outside from the second end portion 27 at the base portion 30. The second terminal 29 is connected to the second switch terminal 25b. The second terminal 29 has a second external terminal 29a that protrudes and is exposed to the outside from the second end portion 27 at the base portion 30. The first external terminal 28a and the second external terminal 29a protrude in parallel.

[0025] 4 and 5, the first terminal 28 has a first locking portion 28b that protrudes and is exposed outward in the width direction of the base portion 30 on the second end portion 27 side. The second terminal 29 has a second locking portion 29b that protrudes and is exposed outward in the width direction of the base portion 30 on the second end portion 27 side. The first locking portion 28b and the second locking portion 29b protrude in opposite directions in the width direction of the base portion 30 and in directions away from each other. The first locking portion 28b and the second locking portion 29b are formed in a claw shape that protrudes more toward the second end portion 27 side.

[0026] 4, the first end 26 of the base portion 30 has a support protrusion 31 that protrudes in the length direction of the reed switch subunit 21. In this embodiment, the support protrusion 31 is formed in a cylindrical shape. The support protrusion 31 is provided at the center of the base portion 30 in the width direction. The support protrusion 31 is also provided at the center of the base portion 30 in the height direction (see FIG. 6).

[0027] (Configuration of housing 22) As shown in FIG. 3, the housing 22 is formed in a square tubular shape capable of accommodating and holding the reed switch subunit 21. The housing 22 of this embodiment has a rectangular square tubular shape when viewed in the length direction of the housing 22. The housing 22 has a first opening 32 into which the reed switch subunit 21 can be inserted from the first end 26 side. The first opening 32 is formed so that an external connector electrically connected to a control unit (not shown) can be fitted. The housing 22 also has a second opening 33 on the opposite side of the first opening 32. The second opening 33 is formed in a rectangular shape with a width direction longer than a height direction when viewed from the opening direction of the second opening 33.

[0028] As shown in FIG. 5 , a support portion 34 is provided on the inner surface of the housing 22 near the first opening 32. The support portion 34 supports the second end 27 of the reed switch subunit 21 when the reed switch subunit 21 is inserted into the housing 22. More specifically, the first locking portion 28b and the second locking portion 29b bite into the support portion 34 when the reed switch subunit 21 is inserted into the housing 22, thereby supporting the second end 27 of the reed switch subunit 21. The support portion 34 is a wall surface that is configured so that the first locking portion 28b and the second locking portion 29b bite into it when the reed switch subunit 21 is inserted into the housing 22. The support portion 34 is deformed by being scraped by the first locking portion 28b and the second locking portion 29b when the reed switch subunit 21 is inserted into the housing 22. 5, the state in which the first locking portion 28b and the second locking portion 29b are biting into the support portion 34 is schematically illustrated.

[0029] 3, the housing 22 has a fixing portion 35 on its outer surface near the second opening 33. The fixing portion 35 is provided on both sides of the housing 22 in the height direction. In this embodiment, the fixing portion 35 has a locking protrusion 35a provided in the center of the housing 22 in the width direction, and a pair of guide protrusions 35b provided at positions on either side of the locking protrusion 35a in the width direction of the housing 22. The locking protrusion 35a has an inclined surface 35c whose protrusion amount increases toward the center of the housing 22 in the length direction. The pair of guide protrusions 35b protrude a constant amount and extend parallel to each other along the length direction of the housing 22.

[0030] (Configuration of rubber member 23) 3 and 6, the rubber member 23 is formed in a rectangular parallelepiped shape. When viewed from the opening direction of the second opening 33, the rubber member 23 has a rectangular shape with a width direction longer than a height direction. The rubber member 23 is fitted into the second opening 33 to seal off the second opening 33 and support the first end 26 of the reed switch subunit 21. More specifically, the rubber member 23 has a support recess 36 into which the support protrusion 31 fits. The support recess 36 has a circular inner peripheral surface so that the entire outer peripheral surface of the cylindrical support protrusion 31 is in close contact with the support recess 36.

[0031] The rubber member 23 also has a plurality of protrusions 37 in the length direction of the reed switch subunit 21 that locally come into pressure contact with the second opening 33. More specifically, the protrusions 37 are provided on both sides of the rubber member 23 in the height direction. In other words, the protrusions 37 protrude from both sides of the rubber member 23 in the height direction. The protrusions 37 are also provided across the entire width direction of the rubber member 23. In other words, the protrusions 37 protrude at a uniform height across 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. Furthermore, since no protrusions 37 are provided on both sides of the rubber member 23 in the width direction, the rubber member 23 has a flat surface 23a that is continuous in the length direction of the rubber member 23.

[0032] (Cover 24 configuration) As shown in FIGS. 3 and 6 , the cover 24 is fixed to the second opening 33 of the housing 22, thereby preventing the rubber member 23 from coming off the second opening 33. Specifically, the cover 24 has a rectangular plate portion 38 that covers the second opening 33 and a tubular portion 39 that extends tubularly from the outer edge of the plate portion 38 to cover the outer periphery of the housing 22. The tubular portion 39 has a pair of slits 39a into which the pair of guide protrusions 35b fit, and a locking piece 39b that is capable of bending in the height direction between the pair of slits 39a. The locking piece 39b has a locking hole 39c into which the locking protrusions 35a fit. The cover 24 is assembled to the housing 22 by moving relative to the housing 22 along the length of the housing 22. During assembly, the movement of the cover 24 is first guided by the guide protrusions 35b that fit into the slits 39a. During assembly of cover 24, locking pieces 39b bend to climb over inclined surfaces 35c of locking projections 35a, and locking projections 35a fit into locking holes 39c, completing assembly. That is, cover 24 is fixed to housing 22 by fitting guide projections 35b into slits 39a and locking projections 35a into locking holes 39c.

[0033] Next, the operation of the reed switch unit 11 configured as above will be described. For example, when the liquid 12 stored in the reservoir tank 13 decreases, the permanent magnet 16 moves downward together with the float 14. When the permanent magnet 16 approaches the reed switch unit 11, the reed switch 25 enters a connected state. This detection of the decrease in the liquid 12 is then 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 embodiment will be described below. (1) The reed switch subunit 21 has its second end 27 supported by the housing 22 on the side of the first opening 32, and its first end 26 supported by the rubber member 23 fitted into the second opening 33. Therefore, rattle of the reed switch 25 relative to the housing 22 is suppressed, along with the reed switch subunit 21. This enables the reed switch unit 11 to detect, with high accuracy, changes in the magnetic field, such as the approach of the permanent magnet 16. Specifically, it is possible to suppress erroneous determinations, such as the controller determining that the amount of liquid 12 has exceeded a threshold before the threshold is reached. Furthermore, the second opening 33 is sealed by the rubber member 23, preventing water from entering the reed switch subunit 21. Furthermore, the rubber member 23 functions to support the first end 26 of the reed switch subunit 21 and seal the second opening 33, thereby suppressing an increase in the number of parts, for example.

[0035] (2) The first end 26 has a support protrusion 31 that protrudes in the longitudinal direction of the reed switch subunit 21, and the rubber member 23 has a support recess 36 into which the support protrusion 31 fits. Therefore, rattling of the first end 26 in a direction intersecting the longitudinal direction of the reed switch subunit 21 is effectively suppressed.

[0036] (3) Because the support protrusion 31 has a cylindrical shape, rattle of the first end 26 is effectively suppressed in all directions intersecting the longitudinal direction of the reed switch subunit 21. In other words, because the support protrusion 31 has a cylindrical shape, it can be supported by the support recess 36 of the rubber member 23 evenly in all directions intersecting the longitudinal direction of the reed switch subunit 21, so rattle in all directions is effectively suppressed.

[0037] (4) The rubber member 23 has a plurality of protrusions 37 in the longitudinal direction of the reed switch subunit 21 that locally come into pressure contact with the second opening 33. This improves the ease of assembly of the rubber member 23 into the second opening 33 and improves the watertightness of the second opening 33. That is, for example, if the rubber member 23 were shaped so that it came into pressure contact with the second opening 33 on a single continuous surface without having any protrusions 37, the frictional resistance would increase when the rubber member 23 was fitted into the second opening 33, but this can be avoided. Also, for example, if the rubber member 23 were shaped so that it came into pressure contact with the second opening 33 on a single continuous surface without having any protrusions 37, there is a risk that the watertightness would be compromised due to partial distortion, but this can be avoided.

[0038] (5) The protruding portions 37 are provided on both sides of the rubber member 23 in the height direction and over the entire width direction, which is longer than the height direction, which improves the ease of assembly of the rubber member 23 into the second opening 33 and improves the watertightness of the second opening 33. That is, a better effect can be obtained compared to, for example, a configuration in which the protruding portions 37 are provided on both sides of the rubber member 23 in the width direction and over the entire height direction, which is shorter than the width direction.

[0039] (6) Since the cover 24 prevents the rubber member 23 from coming off the second opening 33, for example, the rubber member 23 fitted into the second opening 33 is prevented from coming off the second opening 33 due to vibration or the like.

[0040] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. In the above embodiment, the first end 26 has the support protrusions 31, and the rubber member 23 has the support recesses 36 into which the support protrusions 31 fit, but this is not limiting and the rubber member 23 may have another configuration as long as it can support the first end 26. For example, the rubber member 23 may be configured to support the first end 26 by frictional force by pressing against the first end 26 without having the support protrusions 31 and the support recesses 36.

[0041] In the above embodiment, the support protrusion 31 has a cylindrical shape, but this is not limiting and the shape may be changed to another shape. For example, the support protrusion 31 may have a square prism shape. Of course, the shape of the support recess 36 may also be changed according to the shape of the support protrusion 31.

[0042] In the above embodiment, the rubber member 23 has a plurality of protrusions 37 that are in localized pressing contact with the second opening 33, but this is not limited to this, and the rubber member 23 may be configured without the protrusions 37.

[0043] In the above embodiment, the protrusions 37 are provided on both sides of the rubber member 23 in the height direction, but this is not limiting. For example, the protrusions 37 may be provided on only one side of the rubber member 23 in the height direction. Also, for example, the protrusions 37 may be provided on both sides of the rubber member 23 in the width direction, or on only one side of the rubber member 23 in the width direction. Also, the protrusions 37 may be provided on both sides of the rubber member 23 in the height direction and both sides of the rubber member 23 in the width direction.

[0044] In the above embodiment, the protrusion 37 is provided over the entire width, but this is not limited to this. For example, it may be provided on both sides of the width, or only in the center of the width.

[0045] In the above embodiment, three protrusions 37 are provided at equal intervals along the length of the rubber member 23, but this is not limited to this. For example, they may be provided at uneven intervals, or two, four or more protrusions may be provided.

[0046] In the above embodiment, the reed switch unit 11 is provided with the cover 24 that prevents the rubber member 23 from coming off the second opening 33, but this is not limiting and the reed switch unit 11 may not be provided with the cover 24. In this case, it is preferable to provide a protrusion or the like on the housing 22 that prevents the rubber member 23 from coming off. In this way, for example, it is possible to reduce the number of parts in the reed switch unit 11.

[0047] In the above embodiment, the second end 27 side of the reed switch subunit 21 is supported by the support portion 34 by the first locking portion 28b and the second locking portion 29b engaging with each other, but the second end 27 side may be supported by another configuration.

[0048] In the above embodiment, the housing 22 is formed in a rectangular tubular shape, but this is not limited thereto and may be changed to another shape as long as it can accommodate and hold the reed switch subunit 21. For example, the housing 22 may be changed to a cylindrical shape.

[0049] In the above embodiment, the cover 24 is fixed to the housing 22 by fitting the guide protrusions 35b into the slits 39a and the locking protrusions 35a into the locking holes 39c, but this is not limitative and the cover 24 may be fixed to the housing 22 in other ways. For example, the cover 24 may be fixed to the housing 22 by screws.

[0050] In the above embodiment, the housing 22 is an exclusive part provided for the reed switch unit 11, but this is not limitative. For example, the housing 22 may be molded integrally with the reservoir tank 13.

[0051] In the above embodiment, the reed switch unit 11 is used to detect the amount of liquid 12 stored in the reservoir tank 13, but it is not limited to this and may be used in other devices. [Explanation of symbols]

[0052] 11 Reed switch unit 12 liquid 13 Reservoir tank 14 Float 15 Rail 16 Permanent Magnets 17 Unit holder 21 Reed switch subunit 22 Housing 23 Rubber parts 23a flat surface 24 Cover 25 Reed Switch 25a 1st switch terminal 25b Second switch terminal 26 First end 27 Second end 28 Terminal 1 28a 1st external terminal 28b 1st locking part 29 Terminal 2 29a 2nd external terminal 29b Second locking part 30 Base 31 Support protrusion 32 First Opening 33 Second Opening 34 Support part 35 Fixed part 35a Locking protrusion 35b Guide protrusion 35c slope 36 Support recess 37 Protrusion 38 Board part 39 Cylinder part 39a Slit 39b Locking piece 39c Locking hole

Claims

1. an elongated reed switch subunit having a reed switch and a first end and a second end in a longitudinal direction; a cylindrical housing having a first opening into which the reed switch subunit can be inserted from the first end side, the cylindrical housing accommodating and holding the reed switch subunit; Equipped with The reed switch subunit has a second end supported by the housing at a side of the first opening. A reed switch unit, the housing has a second opening opposite the first opening; a rubber member that is fitted into the second opening to make the second opening waterproof and that supports the first end of the reed switch subunit; Reed switch unit.

2. the first end portion has a support protrusion protruding in the length direction of the reed switch subunit, The rubber member has a support recess into which the support protrusion fits.

2. The reed switch unit according to claim 1.

3. The support protrusion has a cylindrical shape.

3. The reed switch unit according to claim 2.

4. the rubber member has a plurality of protrusions extending in the longitudinal direction of the reed switch subunit, the protrusions being in localized pressure contact with the second opening; 2. The reed switch unit according to claim 1.

5. the second opening has a rectangular shape in which a width direction is longer than a height direction when viewed from an opening direction of the second opening, the rubber member has a rectangular shape with a width direction longer than a height direction when viewed from the opening direction of the second opening, The protrusions are provided on both sides of the rubber member in a height direction and across the entire width direction of the rubber member.

5. The reed switch unit according to claim 4.

6. a cover that prevents the rubber member from coming off the second opening; 2. The reed switch unit according to claim 1.

Images