JP2005317360A - Reed switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reed switch that uses a magnetic material having a large diameter equal to or larger than that of a conventional product and is smaller in diameter and smaller than a conventional product and can be manufactured by existing equipment.
SOLUTION: A pair of leads 1 made of a magnetic material and having a contact portion 3 at one end, and a glass tube 2 that encloses the contact portion 3 so as to face each other, at least one of the leads 1 is connected to the contact portion 3 is movable. A contact portion according to the magnetic field applied to the lead 1, the support portion 5 fixed by the glass tube 2 and supporting the entire lead, and the boundary portion 6 positioned between the movable portion 4 and the support portion 5. The movable part 4 has a region 7 having a thickness smaller than that of the other part on the boundary part 6 side. Further, the width of the region 7 whose thickness is smaller than that of the other portion is equal to or less than the width of the other portion.
[Selection] Figure 1

Description

  The present invention relates to a reed switch in which a contact is opened and closed by an external magnetic field, and in particular, a lead piece made of two or more magnetic materials having a contact formed at an end in a longitudinal direction is opposed to the contact with a predetermined minute interval. The present invention relates to a reed switch suitable for a structure in which both ends of a straight glass tube are sealed and fixed.

  FIG. 7 shows an example of the configuration of a conventional reed switch, and FIGS. 7A and 7B are a front view and a plan view, respectively. A reed switch using a lead having such a shape is well known, and the lead of Patent Document 1 has a similar shape. As shown in FIG. 7, the reed switch 20 has two contact plates 23 of a lead 21 formed of a magnetic material such as a 52% Fe—Ni alloy formed by a press machine, which are opposed to each other. A pair of contacts are configured and sealed in the glass tube 22 so as to have a gap amount and an overlap amount. The glass tube 22 is filled with an inert gas such as nitrogen or kept in vacuum so that the contact performance does not change during operation.

  The function of the reed switch is magnetized by the magnetic flux generated by the magnetomotive force from the outside so that the contact portions 23 of the lead 21 made of a magnetic material have different poles, so that an attractive force is exerted between the contact points facing each other with a minute interval. As a result, the movable portion 24 which is formed thinner and functions as a cantilever spring is bent between the contact portion 23 and the support portion 25, and the contact is closed. In the case of an external magnetic retention type reed switch, the attractive force decreases with a decrease in the external magnetomotive force, and the contact opens.

  FIG. 11 is a diagram showing the relationship between the magnetic attractive force curve and the opening force with respect to the gap between the contacts in the external magnetic holding type reed switch. The relationship between the contact gap and the opening force as shown in FIG. 11 is called a reed switch load curve. When the magnetomotive force from the outside is zero, neither the magnetic attractive force nor the separating force works, but when the magnetomotive force is increased, the magnetic attractive force increases as F1 → F2. For a reed switch in which the gap between contacts when the magnetomotive force is zero is Xoff, when the magnetic attractive force becomes F1 by obtaining the magnetomotive force, the magnetic attractive force F1 at x = X1 with respect to the contact gap x. The opening force Fr becomes equal, but when x <X1, F1 <Fr and the reed switch contact is not closed.

  When the magnetomotive force is increased and the magnetic attractive force reaches F2, when x = X0, the magnetic attractive force is in contact with the load curve, and when x <X0, the magnetic attractive force F2> the separating force Fr. The contact is closed.

  8 is a partially enlarged view of the lead 21 in FIG. 7, and FIGS. 8A and 8B are a front view and a plan view, respectively. Such a lead forms the movable part 24 and the contact part 23 through the boundary part 26 which continues from the support part 25 which is not substantially processed by press-working the edge part of a cylindrical magnetic material. The movable part 24 mainly functioning as a cantilever spring is formed thinner than other parts in order to ensure flexibility. In many cases, the movable portion 24 is formed to be particularly thin in a small reed switch, and the width is often widened as shown by the maximum width 28 in FIG.

  When attempting to reduce the size of a reed switch, generally, even when the outer diameter of the glass tube is reduced, the thickness of the glass itself cannot be made very thin, and the inner diameter of the glass tube is often pressed beyond the outer dimensions, and the lead piece In many cases, the maximum width is often limited.

  FIGS. 9A and 9B are a front view and a plan view showing an example of a lead structure when the maximum width is limited, and a magnetic material having the same diameter as that of the example shown in FIG. 8 is used. This is an example. The movable portion 34 formed with a reduced thickness and the support portion 35 that retains the shape of the magnetic material are integrally formed via a boundary portion 36 having a tapered cross section, and the other end of the movable portion is provided at the other end. A contact portion 33 is formed. At that time, since the maximum width 38 is limited, the movable portion 34 must be relatively thick.

  FIG. 12 explains the productivity expected for the above-described two types of reed switches, using the reed switch load curve similar to FIG. 11 described above. The comparative example in FIG. 12 corresponds to the lead 21 in FIG. 8 described above, and an example in which the maximum width is limited using the same-diameter wire is shown in the lead 31 in FIGS. 9A and 9B. It is equivalent. Here, since the opening force is the flexibility of the lead, the inclination of the opening force Frβ when the maximum width is limited using the same diameter wire as compared with the opening force Frα in the comparative example is large, and the stiffness of the lead is large. Is high, that is, the spring property of the lead is hard.

  In FIG. 12, a magnetic attractive force curve F15A is an attractive force curve when a magnetomotive force of 15A (ampere) is given, and similarly F10A is a magnetic attractive force due to a magnetomotive force of 10A. The breaking force straight line Frα15A is in contact with the magnetic attractive force curve F15A and corresponds to a conventional reed switch whose contact is closed by a magnetomotive force of 15A. Similarly, Frα10A is a conventional reed switch whose contact is closed with a magnetomotive force of 10A, Frβ15A is a reed switch with a lead whose maximum width is limited using the same diameter wire material whose contact is closed with a magnetomotive force of 15A, and Frβ10A is 10A. Corresponds to a reed switch whose maximum width is limited using the same diameter wire that closes the contact point by magnetomotive force.

  In FIG. 12, for example, when obtaining a reed switch that closes a contact with a magnetomotive force of 10A according to the prior art, a contact gap corresponding to the x intercept of the breaking force straight line Frα10A may be provided. When using a closed wire with the same diameter and obtaining a reed switch with a reed whose maximum width is limited, a contact gap corresponding to the x intercept of the breaking force straight line Frβ15A may be provided.

  Here, if a reed switch that selectively closes the contact with a magnetomotive force between 10A and 15A is selectively obtained, in the case of the prior art, control should be performed so that the contact gap is between the X intercepts of Frα10A and Frα15A. In the case of a reed switch using a lead having the same diameter wire and the maximum width being limited, the contact gap between Frβ10A and Frβ15A may be similarly controlled. The contact gap range of 10-15A in the figure is an illustration of these ranges. In the case of a reed switch with a lead having a maximum width limited using the same diameter wire material, the gap range to be controlled is remarkably large. It is narrow and productivity is inferior.

  When verifying the magnetomotive force range in which the contact is closed, it is necessary to consider the attractive force curve as described above, but verification of the contact gap range corresponding to the magnetomotive force at which the contact opens will be explained more easily. I can do it. Since the magnetomotive force range in which the contact opens and the magnetomotive force range in which the contact closes are generally linked, the following description will be made from the viewpoint of the open region.

  If the lead is simply considered as a spring, the amount of deflection in which the spring balances the attractive force generated between the contacts closed by the external magnetomotive force can be considered as the contact gap of the reed switch that opens the contact by the magnetomotive force. .

  FIG. 13 is a diagram for explaining the relationship between the flexibility of the lead and the desired contact gap of the reed switch using the spring characteristics of the lead. In order to show the relationship between the flexibility of the lead and the contact gap, FIG. Is plotted corresponding to two leads encapsulated oppositely, that is, a value twice the spring characteristics of a single lead. In this figure, the greater the slope of the characteristic line, the higher the stiffness and the harder the spring. The comparative example in FIG. 13 corresponds to the lead 21 in FIG. 8 described above, and the example with the same diameter and the maximum width limited corresponds to the lead 31 in FIGS. 9A and 9B. is there. In FIG. 13, Fφ0.35-5A indicates the magnetic attractive force when an external magnetomotive force of 5A is applied with the contact of the lead having a magnetic material diameter of 0.35 mm closed, and similarly Fφ0.35 −10A and Fφ0.35-15A are attractive forces with magnetomotive forces of 10A and 15A, respectively. For example, when obtaining a reed switch that opens with a magnetomotive force between 5A and 10A, the gap between the reed switch contacts between the amount of deflection commensurate with Fφ0.35-5A and the amount of deflection commensurate with Fφ0.35-10A. Each gap range is shown in the lower part of FIG. According to FIG. 13, the lead having the maximum width limited has a remarkably narrow contact gap range, and the productivity is inferior unless the machining accuracy is improved.

  Next, FIGS. 10A and 10B are a front view and a plan view showing another example of the lead structure when the maximum width is limited, and FIGS. 9A and 9B. In the same manner as in the example shown in FIG. 2, the magnetic material is changed to a small diameter while the maximum width 48 is limited.

  In this case, FIG. 14 is a diagram for explaining the relationship between the flexibility of the lead and the required contact gap of the reed switch using the spring characteristics of the lead as in FIG. 13, and the comparative example is the lead 21 shown in FIG. The example in which the maximum width is limited with a small diameter corresponds to the lead 41a in FIGS. 10 (a) and 10 (b). If the magnetic body diameter is different, the magnetic flux obtained even if the same magnetomotive force is applied from the outside is different, so that the attractive force generated between the contacts of the reed switch is also different. In FIG. 14, Fφ0.25-5A indicates the magnetic attractive force when an external magnetomotive force of 5A is applied in a state where the contact of the lead having a magnetic material diameter of 0.25 mm is closed, and similarly Fφ0.25. −10A and Fφ0.25-15A are attractive forces with magnetomotive forces of 10A and 15A, respectively, which are lower than those of the magnetic material diameter φ0.35, respectively. According to FIG. 14, it can be seen that the stiffness of the example having a narrow diameter and the maximum width is lower than that of the comparative example, and a flexible spring property is obtained, but the attractive force is also low according to the magnetic material diameter. It is considered that a reed switch that opens with a magnetomotive force in the range of 10 to 10A can be obtained relatively easily, but in the range of 10A to 15A, the productivity is remarkably inferior.

  Further, in FIGS. 10C and 10D, in general, the length of the movable portion is ensured also using the region used as the contact portion, and the movable portion also serves as the contact portion, so that the cantilever is used. FIG. 10 (c) and FIG. 10 (d) are a front view and a plan view, respectively, which are intended to ensure the flexibility of the spring. The movable portion 44b also serving as the contact has the same thickness as the movable portion 44a in FIGS. 10A and 10B described above, and is formed to have the same thickness including the range corresponding to the contact portion 43a. Yes.

  In order to keep the suction force between the contacts of the reed switch to the maximum, it is necessary to keep the overlap area of the opposing leads approximately the same as the cross-sectional area of the leads. In such a case, the position where the thickness of the contact and the overlapping length are the same is considered as the optimum position. In the case of the configuration shown in FIGS. 10C and 10D, the movable portion 44b that also serves as the contact is extended as described above, so that the flexibility is slightly improved, but the movable portion 44b that also serves as the contact is provided. 10 is thin and wide, it is necessary to control the overlap length to be small in order to keep the overlap area as large as the cross-sectional area of the contact portion. FIG. 10 (a) and FIG. Compared with the configuration provided with the contact portion as shown in b), higher assembly accuracy is required and the productivity is inferior.

  Next, FIG. 16 exemplifies the change in magnetic attractive force obtained by the external magnetomotive force applied with the lead contact closed, for each diameter of the magnetic material. According to FIG. 16, it can be seen that both the absolute value of the attractive force and the change in attractive force due to the magnetomotive force are larger when the diameter is larger, and smaller when the diameter is smaller. For example, in the case of a magnetic material with φ0.25, the change in attractive force is remarkably small with magnetomotive forces of 10A and 15A versus 5A and 10A, and hardly changes at 15A or more. This is considered to be because the smaller the diameter, the smaller the saturation magnetic flux density with respect to the magnetomotive force. In the saturation magnetic flux region, even if the magnetomotive force changes, the attractive force does not follow and the reed switch is not established. When the φ0.25 magnetic material in FIG. 14 is used, the contact gap range from 10A to 15A is remarkably narrow. When the magnetic material diameter is reduced, the sensitivity range that can be produced is limited. Understand. For this reason, when a thin magnetic material is used, it is not possible to obtain a reed switch with a wide range of manufacturable sensitivity that can be used for many purposes.

  By the way, not only the reed switch but also various kinds of products are produced, it is desirable that the same production equipment can be applied.

  FIG. 17 is a diagram showing the relationship between the diameter and strength (stiffness) of a magnetic material having the same length. According to FIG. 17, the strength of a magnetic material having a diameter of φ0.25 mm is only about ¼ that of a magnetic material having a diameter of φ0.35 mm, and it is difficult to divert the production equipment constructed with a conventional product having a diameter of φ0.35 mm. is there. In addition, even when using a reed switch, handling becomes difficult.

JP-A-11-162308

  As mentioned above, when trying to reduce the size of a reed switch, especially when trying to reduce the outer diameter, in order to ensure the flexibility of the lead, a magnetic material with a smaller diameter than the conventional product Therefore, the sensitivity range that can be produced has been extremely limited. In addition, the small-diameter magnetic material used in this case and the reed switch manufactured using the same are extremely fragile compared to conventional products, making it difficult to divert existing production equipment. Even in the use of, it has been difficult to handle compared to conventional products.

  In this situation, an object of the present invention is to provide a miniaturized reed switch that can be manufactured using a magnetic material having a size that can be used in many kinds and a production facility.

  In Patent Document 1, an improvement in lead stiffness is realized by controlling and suppressing the area reduction rate in the vicinity of the connecting portion between the movable portion where the stress is concentrated and the boundary portion. It supplements about the area reduction rate. When the lead is pressed, the material moves in the axial direction of the lead, and the cross-sectional area after processing decreases from the original cross-sectional area. This reduction in cross-sectional area is called area reduction, and the rate of reduction with respect to the original cross-sectional area is called area reduction. In the present invention, while reducing the area reduction rate, the condition of obtaining appropriate stiffness is established by accelerating the area reduction as opposed to the technique of Patent Document 1, thereby solving the problems of the present invention.

  That is, according to the present invention, it is provided with a pair of leads made of a magnetic material and having a contact portion at one end thereof, and an enclosing member that encloses the contact portion in a cavity with the contact portion facing each other, and at least one of the leads includes the contact A movable part connected to the part, a support part fixed by the enclosing member and supporting the entire lead, and a boundary part located between the movable part and the support part, and depending on a magnetic field applied to the lead A reed switch that contacts or opens the contact portion, wherein the movable portion has a thin region formed on the side of the boundary portion with a thickness reduced as compared with other portions.

  According to the present invention, there is provided a reed switch characterized in that the width of the thin region is equal to or less than the width of the other portion.

  According to the present invention, there is provided a reed switch characterized in that a surface of the thin region and a surface of the boundary portion are connected via a curved surface.

  According to the present invention, there is provided a reed switch characterized in that the contact portion and the movable portion are continuously formed with equal thickness and width.

  As described above, according to the present invention, when trying to reduce the size of the reed switch, especially when trying to reduce the outer diameter, a magnetic material having a diameter larger than that of the conventional product is used. However, sufficient lead flexibility can be secured, and it is possible to produce with a sensitivity range equal to or higher than that of the conventional product despite its small size. In addition, since a magnetic material with a diameter larger than that of conventional products can be used, it is possible to divert existing production equipment while achieving downsizing, and a reed switch that can be handled in the same way as conventional products is obtained. It was.

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

  FIG. 1 is a view showing a schematic structure through the inside of a reed switch according to an embodiment of the present invention, and FIGS. 1 (a) and 1 (b) are a front view and a plan view, respectively. Referring to FIG. 1, a reed switch 10 is encapsulated so that a pair of leads 1 made of a magnetic material and the leading ends of the leads 1 face each other and the other ends of the leads 1 extend in opposite directions. This point is common with the prior art.

  2 is an enlarged view of the lead 1 of FIG. 1, FIG. 2 (a) is a front view, and FIG. 2 (b) is a plan view. The lead 1 is formed by integrating a contact portion 3 formed by pressing a magnetic material as a raw material to reduce the thickness, a movable portion 4 having a spring property, and a support portion 5 maintaining the shape of the magnetic material. In addition, a region 7 having a thickness one step smaller than other portions of the movable portion 4 is provided at a portion of the movable portion 4 that contacts the boundary portion 6 connected to the support portion 5. This is a structure in which the end connected to the boundary portion 36 of the movable portion 34 is formed one step thinner than the other portions with respect to the configuration of FIG. 9A and FIG.

  As shown in FIG. 2, the region 7 in which the thickness of the movable portion is reduced is made thinner than other regions, and the width is equal to or less than that of the other regions of the movable portion. As a result, the maximum width 8 is equivalent to the maximum width 38 in FIG. 9B of the prior art example.

  By the way, when the lead is pressed, the material moves in the axial direction of the lead, and the cross-sectional area after processing decreases from the original cross-sectional area. It is important to obtain the desired stiffness by controlling the area reduction rate, which is the reduction rate of the cross-sectional area at this time.

  FIG. 18 shows the result of measuring the width of the lead obtained by the embodiment of the present invention. The horizontal axis indicates the position in the lead, the boundary with the movable part is 0, the movable part side is positive, the support part side is negative, and the vertical axis indicates the width of each position. ) And plotted. In the figure, what is plotted as the present invention is based on the configuration shown in FIG. 2, and what is plotted as a comparative example is that of the configuration example according to the prior art shown in FIG. FIG. 19 is a plot of the area reduction rate on the vertical axis with respect to the horizontal axis similar to FIG. From these two figures, it can be seen that according to the embodiment of the present invention, the vicinity of the connecting portion between the boundary portion and the movable portion is greatly reduced while limiting the maximum width.

  As described in Patent Document 1, stress concentrates in the vicinity of the connecting portion between the movable portion and the boundary portion, which greatly affects the stiffness of the lead. Even when a relatively large diameter magnetic material is used, the maximum width is limited, and the required flexibility cannot be ensured by the conventional technology, according to the present invention, the vicinity of the connecting portion between the movable portion and the boundary portion is provided. By actively reducing the surface, it is possible to obtain leads having a practical range of flexibility.

  FIG. 15 is a diagram for explaining the relationship between the flexibility of the lead and the required contact gap of the reed switch by using the spring characteristic of the lead as in FIG. 13 used for the description of the prior art. This corresponds to the lead 21 in FIG. As shown in FIG. 15, the lead according to the present invention uses a magnetic material having the same diameter as that of the conventional one and limits the maximum width, and realizes a stiffness substantially equivalent to that of the conventional technology that allows the maximum width to be expanded. The contact gap range corresponding to the range is also equivalent, and the same sensitivity productivity as that of the conventional thick diameter is realized.

  As mentioned above, since magnetic materials with the same diameter as before are used, conventional production equipment can be diverted while being smaller, and a reed switch that can handle the same as before with respect to handling during use has been realized. .

  FIG. 3 is a view showing a schematic structure of a reed switch according to another embodiment of the present invention, and shows an application example to an offset contact reed switch. FIG. 3A and FIG. 3B are a front view and a plan view, respectively. Referring to FIG. 3, in the reed switch 50, the movable lead 51a and the fixed lead 51b are formed such that the contact portion 53a and the contact portion 53b formed at the tip ends of the movable lead 51a and the fixed lead 51b made of a magnetic material face each other. The glass tube 52 is provided so that the other end of the tube extends in opposite directions.

  4A and 4B are a front view and a plan view, respectively, of the movable lead 51a and the fixed lead 51b shown in FIG. The movable lead 51a has the same configuration as the lead 1 in FIGS. 1 and 2 described above. On the other hand, the fixed lead 51b does not have a movable part, and the contact part 53b is continuously formed from the support part 55b through the boundary part, and the movable part is omitted as compared with the movable lead 51a. In addition, the range of insertion into the glass tube is greatly shortened, and the length of the glass tube is shortened in the configuration of the reed switch as in the conventional offset contact reed switch. By combining the movable lead 51a according to the present invention with such an offset contact reed switch, a reed switch in which the length and outer diameter of the glass tube are reduced can be obtained.

  FIG. 5 shows a lead according to another embodiment of the present invention. FIGS. 5A and 5B are a front view and a plan view, respectively. The lead 61 is integrally provided with a contact portion 63 formed by reducing the thickness by press working, a movable portion 64 having spring properties, and a support portion 65 that maintains the shape of the magnetic material. 64 is provided with a region 67 in which the thickness of the movable portion 64 is reduced by one step from that of the other portion of the movable portion 64 at the portion in contact with the boundary portion 66 with the support portion 65 of the embodiment. Is the same.

  FIG.5 (c) is the elements on larger scale of the A section of Fig.5 (a). According to the present embodiment, an extension portion 68 is provided, and the planes of the region 67 and the boundary portion 66 with reduced thickness are made continuous with curved surfaces having R. By forming this portion with a curved surface, it is possible to further reduce the surface area near the connecting portion between the movable portion and the boundary portion than in the above-described embodiment, thereby realizing a more flexible lead.

  FIG. 6 shows a lead according to still another embodiment of the present invention, and FIGS. 6A and 6B are a front view and a plan view, respectively. This is an example of a configuration in which the movable portion 74 also serves as a contact portion, where 71 is a lead, 75 is a support portion, 76 is a boundary portion, 77 is a reduced thickness region, and 78 is the maximum width of the lead.

  As explained in the prior art, in the case of configuring a reed switch, in order to keep the suction force to the maximum, the maximum suction force is maintained by keeping the overlap area of the opposing leads substantially equal to the cross-sectional area of the lead. Can be obtained. When the contact points of each other are the same shape and face each other without any deviation, the overlap area and the lead cross-sectional area are the same when the contact thickness and the overlap length are the same. Generally, the thickness of the contact portion of the lead is set so as to optimize the overlap length, and the lead 1 shown in FIGS. 1 and 2 also has such a configuration.

  On the other hand, in the case of the lead structure shown in FIG. 6, since the thickness of the movable portion 74 is relatively large due to the maximum width limitation, the overlap length is made equal to the thickness of the contact portion even if the movable portion 74 also serves as a contact. It is relatively easy to control. In such a case, a configuration in which an independent contact is not provided and the movable portion 74 also serves as a contact portion is applicable.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic structure of the reed switch by embodiment of this invention is shown, Fig.1 (a) is a front view, FIG.1 (b) is a top view. 2A is a partially enlarged view of the lead of FIG. 1, FIG. 2A is a front view, and FIG. 2B is a plan view. The schematic structure of the reed switch by other embodiment of this invention is shown, Fig.3 (a) is a front view, FIG.3 (b) is a top view. 3 shows the lead of FIG. 3, FIG. 4 (a) is a front view, and FIG. 4 (b) is a plan view. The figure which shows the lead | read | reed by other embodiment of this invention, FIG.5 (a) is a front view, FIG.5 (b) is a top view, FIG.5 (c) is the elements on larger scale of A part. FIG. 6A is a partially enlarged view of a lead according to still another embodiment of the present invention, FIG. 6A is a front view, and FIG. 6B is a plan view. FIG. 7A is a front view and FIG. 7B is a plan view showing a schematic structure of a general reed switch according to the prior art. FIG. 8A is a partially enlarged view of the lead of FIG. 7, FIG. 8A is a front view, and FIG. 8B is a plan view. FIG. 9A is a partially enlarged view of a lead when the maximum width in the prior art is limited, FIG. 9A is a front view, and FIG. 9B is a plan view. FIG. 10A is a partial enlarged view of a lead when the maximum width is limited in another conventional technique, FIG. 10A is a front view, FIG. 10B is a plan view, and FIG. FIG. 10D is a plan view in the case where the movable portion also serves as a contact portion. The figure which shows the relationship of the magnetic attraction force curve with respect to the space | gap between contact points, and a separating force. The figure which shows two types of reed switch load curves. The figure which shows the relationship between the flexibility of a lead | read | reed, and the required contact gap of a reed switch. The figure which shows the required contact gap of a reed switch using the spring characteristic of a reed. The figure which shows the relationship between the flexibility of a lead | read | reed, and the required contact gap of a reed switch using the spring characteristic of a lead | read | reed. The figure which shows the relationship between the magnetomotive force with respect to the diameter of a lead material, and a magnetic attraction force. The figure which shows the relationship between the diameter of lead material, and intensity | strength (stiffness). The figure which shows the width | variety from the boundary part of a lead to a movable part. The figure which shows the area reduction rate ranging from the boundary part of a lead to a movable part.

Explanation of symbols

1, 21, 31, 41a, 41b, 61, 71 Lead 2, 22, 52, 62 Glass tube 3, 23, 33, 43a, 63 Contact part 4, 24, 34, 44a, 44b, 64, 74 Movable part 5 , 25, 35, 45a, 45b, 65, 75 Support portions 6, 26, 36, 46a, 46b, 56, 66, 76 Border portions 7, 57, 67, 77 Regions 8, 28, 38, 48 with reduced thickness 78 Maximum lead width 10, 20, 50 Reed switch 51a Movable lead
51b Fixed lead 53a Movable lead contact portion 53b Fixed lead contact portion 54a Movable lead movable portion 55a Movable lead support portion 55b Fixed lead support portion 68 Extension portion

Claims (4)

  A pair of leads made of a magnetic material and having a contact portion at one end; and an enclosing member that encloses the contact portion in a cavity with the contact portion facing each other, wherein at least one of the leads is connected to the contact portion; It has a support part fixed by the enclosing member and supporting the entire lead, and a boundary part located between the movable part and the support part, and contacts or opens the contact part according to the magnetic field applied to the lead. The reed switch, wherein the movable part has a thin region formed on the side of the boundary part with a thickness less than that of the other part.   The reed switch according to claim 1, wherein a width of the thin region is equal to or less than a width of the other portion.   3. The reed switch according to claim 1, wherein a surface of the thin region and a surface of the boundary portion are connected via a curved surface. 4.   The reed switch according to any one of claims 1 to 3, wherein the contact portion and the movable portion are continuously formed with equal thickness and width.

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