An ultra-small relay with high creepage distance

Abstract

The present invention discloses an ultra-small relay with a high creepage distance, comprising a base portion and a movable spring-armature combination; the base portion includes a coil, an iron core, a static spring, coil terminals, and a first plastic body that is assembled into a single unit by injection molding. Within the base portion, the static spring injection-molded into the first plastic body comprises only a normally open static spring blade located at the other end of the first plastic body corresponding to the coil axis, and a soldering pad corresponding to a soldering plate structure at least for supporting the movable spring-armature combination at a mid-position along the coil axis, without a normally closed static spring blade. The present invention effectively increases the creepage distance between the coil and the contacts without increasing the size of the relay, thereby meeting the increasingly stringent creepage distance requirements for relay inputs and outputs in new energy, automotive, and other fields.

Description

Technical Field

[0001] The present invention relates to the technical field of relays, and in particular to an ultra-small relay with a high creepage distance. Background Art

[0002] Existing ultra-small relays usually integrate the cut static spring piece with the coil, base, etc. through injection molding. The lead pins of the static spring piece and the lead pins of the coil terminal are formed by bending the cut piece after injection molding. The lead pins of this ultra-small relay are usually distributed along both sides of the coil axis. Figure 1 This is a schematic diagram of the three-dimensional structure of a subminiature relay in the prior art (excluding the housing); Figure 2 This is a structural diagram of a spring-armature combination of a subminiature relay in the prior art; Figure 3 FIG. 1 is a structural diagram of the base portion of a subminiature relay in the prior art; Figure 1 、 Figure 2 、 Figure 3As shown, this subminiature relay of the prior art is assembled together by injection molding a coil, an iron core 101, a static spring and a coil terminal 102 to form a base portion 100 including a plastic body 109, wherein the static spring includes two normally open static spring leaves 103, two normally closed static spring leaves 104 and two common end spring leaves 105; the normally open static spring leaves 103, the normally closed static spring leaves 104 and the common end spring leaves 105 are respectively provided with a normally open static spring lead-out pin 1031, a normally closed static spring lead-out pin 1041 and a common end lead-out pin 1051 exposed outside the plastic body 109; the portions of the normally open static spring leaves 103 and the normally closed static spring leaves 104 exposed at the upper end of the plastic body are also connected to a normally open static contact 1032 and a normally closed static contact 1042, respectively. The movable spring-armature assembly 106 of this subminiature relay is constructed by injection molding two sets of movable springs 107 and an armature 108 into an integrated structure encompassing a plastic component 110. Each set of movable springs 107 has two ends, one exposed outside the plastic component 110, designated as a normally open side 1071 and the other exposed outside the plastic component 110. A welding tab structure 1073 is located in the middle, also exposed outside the plastic component 110. The normally open and normally closed movable contacts are mounted on the normally open and normally closed sides 1071 and 1072 of the movable springs 107, respectively. When the movable spring-armature assembly 106 is mounted on the base 100, the welding tab structure 1073 of the movable spring-armature assembly 106 is welded to the soldering pad of the common-end spring 105 of the base 100, forming a seesaw structure. In the base portion 100, the lead pin 1021 of the coil terminal 102 is located at one end of the plastic body 109, the normally closed static spring lead pin 1041, the common terminal lead pin 1051 and the normally open static spring lead pin 1031 are arranged in sequence from one end of the plastic body 109 to the other end of the plastic body 109, and the normally open static spring lead pin 1031 is located at the other end of the plastic body 109. Figure 3 As shown, due to the small size of the product and the compact overall structure, the creepage distance M between the coil terminal 102 and the static spring (normally closed static spring piece 104) and the creepage distance N between the coil terminal 102 and the static contact (normally closed static contact 1042) are both short, which cannot meet the increasingly high safety requirements (i.e., high creepage distance) for relay input and output (i.e., between coil and contact) in new energy, automotive and other fields. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide an ultra-small relay with a high creepage distance. Through structural improvements, the creepage distance between the coil and the contacts can be effectively increased without increasing the volume of the relay, thereby meeting the increasingly high safety requirements for relay input and output in the fields of new energy, automotive, etc.

[0004] The technical solution adopted by the present invention to solve its technical problems is: an ultra-small relay with a high creepage distance, comprising a base portion and a moving spring-armature combination; the base portion comprises a coil, an iron core, a static spring, a coil terminal, and a first plastic body that is assembled into an integral part of the coil, the iron core, the static spring, and the coil terminal by injection molding, and the first plastic body completely covers the coil; the pole surfaces at both ends of the iron core protrude from the first plastic body to the upper end of the first plastic body and are respectively located at both ends of the first plastic body, and the part of the coil terminal exposed from the first plastic body is located at one end of the first plastic body; the moving spring-armature combination comprises two sets of moving spring leaves, an armature, and a first plastic body that is assembled into an integral part of the coil, the iron core, the static spring, and the coil terminal by injection molding. the movable spring-armature assembly is provided with a welding piece structure in the middle of the movable spring-armature assembly, and the movable spring-armature assembly is mounted on the middle position of the top end of the base part through the welding piece structure so that the two ends of the armature exposed in the movable spring-armature assembly correspond to the pole surfaces at the two ends of the iron core respectively; in the base part, the static spring injection-molded in the first plastic body only includes a normally open static spring piece at the other end of the first plastic body and a soldering base corresponding to the middle position of the first plastic body for at least supporting the welding piece structure of the movable spring-armature assembly without a normally closed static spring piece, so as to increase the creepage distance between the coil terminal and the static spring outside the first plastic body by eliminating the normally closed static spring piece.

[0005] The axis of the coil is arranged horizontally, and the iron core is in a U-shape.

[0006] A welding piece structure is respectively provided on both sides of the middle of the movable spring-armature combination, and the two welding piece structures are respectively integrated into a corresponding group of movable spring pieces and exposed outside the second plastic body; the movable spring piece is an asymmetric structure relative to the welding piece structure, and the movable spring piece is provided with a normally open side exposed outside the second plastic body on the side corresponding to the normally open static spring piece, and the normally open side of the movable spring piece is equipped with a normally open movable contact; the other side of the movable spring piece opposite to the normally open side is completely covered in the second plastic body.

[0007] The horizontal cross-section of the first plastic body is rectangular or nearly rectangular, and a first groove is provided at the side wall of the first plastic body corresponding to the long side of the rectangle, corresponding to the creepage path between the portion of the coil terminal exposed in the first plastic body and the soldering pad exposed in the first plastic body, so as to utilize the first groove to increase the creepage distance between the portion of the coil terminal exposed in the first plastic body and the soldering pad.

[0008] The horizontal cross-section of the first plastic body is rectangular or nearly rectangular; a first retaining wall is provided on the side wall of the first plastic body corresponding to the long side of the rectangle and at the top end close to one end of the first plastic body, protruding upward, so that the portion of the coil terminal exposed from the first plastic body can creep along the side wall of the first plastic body corresponding to the short side of the rectangle through the creepage path between the iron core and the normally open contact.

[0009] A second groove is provided on the side wall of the first plastic body corresponding to the short side of the rectangle, corresponding to the creepage path between the portion of the coil terminal exposed from the first plastic body and one end of the iron core, so as to utilize the second groove to increase the creepage distance between the portion of the coil terminal exposed from the first plastic body through the iron core and the normally open contact.

[0010] A second retaining wall is provided at the upper end of the first plastic body in the creepage path corresponding to the other end of the iron core and the normally open contact, so as to utilize the second retaining wall to further increase the creepage distance between the part of the coil terminal exposed from the first plastic body through the iron core and the normally open contact.

[0011] The movable spring-armature assembly further includes a magnetic steel, which is distributed along the length direction of the armature and stacked with the armature, and the magnetic steel is biased toward the other end of the first plastic body.

[0012] In the movable spring piece, a common end lead-out pin exposed outside the first plastic body is further downwardly provided at the soldering station, and the common end lead-out pin is biased toward the other end of the first plastic body.

[0013] The two sets of dynamic springs are electrically connected at the other side corresponding to the normally open side via a connecting piece, and the connecting piece is completely enclosed in the second plastic body; the connecting piece is integrally connected to the two sets of dynamic springs by integral molding, or the connecting piece is a separate part, and the two ends of the connecting piece are respectively connected to the two sets of dynamic springs by overlapping or welding.

[0014] The connecting piece is close to the end position of the corresponding end of the second plastic body, so that there is enough space for placing the magnetic steel.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. Because the static spring injection-molded into the first plastic body in the base portion of the present invention comprises only a normally open static spring blade located at the opposite end of the first plastic body from the coil axis, and a soldering pad corresponding to a soldering plate structure midway along the coil axis that supports at least the movable spring-armature assembly, without a normally closed static spring blade. This structure of the present invention increases the creepage distance between the coil terminal and the static spring by eliminating the normally closed static spring blade from the base portion. This effectively increases the creepage distance between the coil and the contacts without increasing the relay's size, thereby meeting the increasingly stringent safety requirements for relay inputs and outputs in new energy, automotive, and other fields.

[0017] 2. The present invention provides a first groove in the first plastic body in the creepage path between the relay input and output (i.e., between the coil and the contact) corresponding to the coil terminal and the soldering station, thereby further increasing the creepage distance between the coil and the contact.

[0018] 3. The present invention adopts a method in which a second groove and a second retaining wall are provided in the first plastic body in the creepage path between the coil terminal and the normally open contact at the relay input and output (i.e., between the coil and the contact), and the first retaining wall is used to change the creepage path from crawling along the side wall of the first plastic body corresponding to the long side of the rectangle to crawling along the side wall of the first plastic body corresponding to the short side of the rectangle, thereby further increasing the creepage distance between the coil and the contact.

[0019] 4. The present invention utilizes a soldering pad for supporting the soldering lug structure of the movable spring-armature assembly at the position corresponding to the common end of the first plastic body, without any lead pins. Furthermore, the two sets of movable springs are integrally connected at the other side corresponding to the normally open side by a connecting piece. This structure electrically connects the two sets of movable springs via the connecting piece, achieving series connection of the normally open contacts. The contact gap is twice the contact gap of two sets of normally open relays, effectively increasing the contact gap, the withstand voltage of the disconnected contacts, and improving the product's breaking capacity. Thus, the required contact gap withstand voltage and the distance of the disconnected contact gap can be met without the need for external series wiring.

[0020] 5. The present invention utilizes magnets distributed along the length of the armature and stacked with the armature, with the magnets biased toward the other end of the first plastic body. This unbalanced dual magnetic circuit structure provides a stronger biasing force toward the normally open end, thus avoiding the difficulty or difficulty in actuating the seesaw relay due to the lack of normally closed contact pressure, ensuring reliable relay operation.

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments; however, the ultra-small relay with a high creepage distance of the present invention is not limited to the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the three-dimensional structure of a subminiature relay in the prior art (excluding the housing);

[0023] Figure 2 This is a structural diagram of a spring-armature combination of a subminiature relay in the prior art;

[0024] Figure 3 This is a schematic diagram of the three-dimensional structure of the base portion of a subminiature relay in the prior art;

[0025] Figure 4 1 is a schematic diagram of the three-dimensional structure of the first embodiment of the present invention (excluding the housing);

[0026] Figure 5 It is a left side view of the first embodiment of the present invention (excluding the housing);

[0027] Figure 6 It is a right side view of the first embodiment of the present invention (excluding the housing);

[0028] Figure 7 1 is a cross-sectional view of the structure of embodiment 1 of the present invention (including the housing);

[0029] Figure 8 is a schematic diagram of the three-dimensional structure of the base portion of the first embodiment of the present invention;

[0030] Figure 9 is a cross-sectional view of the base portion of the first embodiment of the present invention;

[0031] Figure 10 1 is a schematic diagram of the three-dimensional structure of the movable spring armature assembly according to the first embodiment of the present invention;

[0032] Figure 11 1 is a bottom view of the movable spring-armature assembly according to the first embodiment of the present invention;

[0033] Figure 12 1 is a bottom view of the movable spring-armature assembly (without the second plastic body) according to the first embodiment of the present invention;

[0034] Figure 13 1 is a schematic diagram of the three-dimensional structure of the movable spring-armature assembly (excluding the second plastic body) according to the first embodiment of the present invention;

[0035] Figure 14 is a schematic diagram of the magnetic circuit structure of Example 1 of the present invention;

[0036] Figure 15 This is a cross-sectional view of the structure of the first embodiment of the present invention (excluding the housing and with the normally closed end of the magnetic circuit closed);

[0037] Figure 16 This is a cross-sectional view of the structure of the first embodiment of the present invention (excluding the housing, and the normally open end of the magnetic circuit is closed);

[0038] Figure 17 Schematic diagram of the distribution of coil terminals and static springs in Example 1 of the present invention;

[0039] Figure 18 This is a schematic diagram of the application of the first embodiment of the present invention, wherein the coil terminal, the static spring and the dynamic spring piece cooperate with each other;

[0040] Figure 19 1 is a schematic diagram of the three-dimensional structure of the second embodiment of the present invention (excluding the housing);

[0041] Figure 20 is a schematic diagram of the three-dimensional structure of the base portion of the second embodiment of the present invention;

[0042] Figure 21 It is a structural diagram of the movable spring-armature assembly (excluding the second plastic body) of the second embodiment of the present invention. DETAILED DESCRIPTION

[0043] Example 1

[0044] See also Figures 4 to 18 As shown, a subminiature relay with a high creepage distance of the present invention includes a housing 1, a base portion 2, and a movable spring-armature assembly 3; the base portion 2 includes a coil 26, an iron core 21, a static spring, a coil terminal 22, and a first plastic body 23 that is assembled into an integral part by injection molding of the coil 26, the iron core 21, the static spring, and the coil terminal 22, and the first plastic body 23 completely covers the coil 26. The coil 26 includes a coil frame and enameled wire. In this embodiment, the axis of the coil 26 is horizontally arranged, and the pole surfaces 2 at both ends of the iron core 21 are 11 protrudes from the first plastic body 23 to the upper end of the first plastic body 23 and is respectively located at both ends of the first plastic body 23. There are two coil terminals 22, and the two coil terminals 22 are respectively located at one end of the first plastic body 23, that is, the portion of the coil terminal 22 exposed from the first plastic body is located at one end of the first plastic body. The portion of the coil terminal 22 exposed from the first plastic body includes a coil lead pin 221. The coil lead pin 221 of the coil terminal 22 is roughly located at a corner position at one end of the first plastic body 23. The first plastic body 23 contains The movable spring-armature assembly 3 includes two sets of movable springs 31, an armature 32, and a second plastic body 33 that is assembled into an integral part by injection molding. In the direction of the coil axis, the armature 32 is in the middle, and the two sets of movable springs 31 are located on both sides of the armature 32. A welding piece structure 311 is provided on both sides of the middle of the movable spring-armature assembly 3. The welding piece structure 311 of the movable spring-armature assembly 3 is installed in the middle position of the top of the base part 2 and exposes the movable spring-armature assembly 3. The ends of the armature 32 in the second plastic body 33 mate with the pole surfaces 211 at both ends of the iron core 21. In the base portion 2, the static spring injection-molded into the first plastic body 23 comprises only a normally open static spring piece 24 at the other end of the first plastic body 23 and a soldering pad 25 located in the middle of the first plastic body 23, which at least supports the soldering piece structure 311 of the movable spring-armature assembly 3. The normally closed static spring piece is omitted. This eliminates the normally closed static spring piece, thereby increasing the creepage distance between the coil terminals and the static spring outside the first plastic body. In this embodiment, the iron core is U-shaped.

[0045] In this embodiment, the welding piece structure 311 is integrally provided in the movable spring piece 31 and exposed outside the second plastic body 33; the movable spring piece 31 is an asymmetric structure relative to the welding piece structure. The movable spring piece 31 is provided with a normally open side 312 exposed outside the second plastic body on the side corresponding to the normally open static spring piece. The normally open side 312 of the movable spring piece is equipped with a normally open movable contact 313, and the other side of the movable spring piece 31 opposite to the normally open side is completely covered by the second plastic body 33.

[0046] Since the normally closed static spring and the normally closed side of the dynamic spring of the seesaw type relay are removed, the invention becomes a normally open seesaw type relay.

[0047] In this embodiment, the horizontal cross-section of the first plastic body 23 is rectangular or nearly rectangular. At the side wall of the first plastic body 23 corresponding to the long side of the rectangle, that is, the side wall 231 parallel to the coil axis, a first groove 232 is provided in the creepage path between the portion of the coil terminal 22 exposed in the first plastic body and the soldering pad 25 exposed in the first plastic body 23, so as to utilize the first groove 232 to increase the creepage distance between the portion of the coil terminal 22 exposed in the first plastic body and the soldering pad 5.

[0048] In this embodiment, a first retaining wall 235 is provided on the side wall 231 of the first plastic body 23 corresponding to the long side of the rectangle and protruding upward from the top end near one end of the first plastic body 23, so that the portion of the coil terminal 22 exposed from the first plastic body can creep along the side wall 233 of the first plastic body 23 corresponding to the short side of the rectangle through the creepage path between the iron core 21 and the normally open contact.

[0049] In this embodiment, in the first plastic body 23, a second groove 234 is provided at the side wall of the first plastic body 23 corresponding to the short side of the rectangle, that is, the side wall 233 perpendicular to the coil axis, corresponding to the creepage path between the portion of the coil terminal 22 exposed in the first plastic body and one end of the iron core 21, so as to utilize the second groove 234 to increase the creepage distance between the portion of the coil terminal 22 exposed in the first plastic body through the iron core and the normally open contact.

[0050] In this embodiment, a second retaining wall 236 is further provided at the upper end of the first plastic body 23 in the creepage path corresponding to the other end of the iron core 21 and the normally open contact, so that the second retaining wall 236 can be used to further increase the creepage distance between the portion of the coil terminal 22 exposed from the first plastic body through the iron core and the normally open contact.

[0051] In this embodiment, the movable spring-armature assembly 3 further includes a magnet 34. The magnet 34 is distributed along the length of the armature, which is also the axis of the coil, and is stacked with the armature 32. The magnet 34 is biased toward the other end of the first plastic body, and in fact, toward the normally open side 312 of the movable spring 31. In other words, the centerline of the magnet 34 is offset relative to the centerline of the armature 32 and is biased toward the normally open end of the magnetic circuit.

[0052] In this embodiment, the two sets of movable springs 31 are electrically connected at the other side corresponding to the normally open side via a connecting piece 35, and the connecting piece 35 is completely enclosed in the second plastic body 33. The connecting piece can be integrally molded between the other sides corresponding to the normally open side of the two sets of movable springs 31. In this case, the two sets of movable springs 31 are a single part, generally forming a U-shape. The connecting piece can also be a separate part, with both ends of the connecting piece fixed to the other sides corresponding to the normally open side of the two sets of movable springs 31 by welding, or the two ends of the connecting piece are placed on the other sides corresponding to the normally open side of the two sets of movable springs 31 by injection molding to achieve close contact.

[0053] In this embodiment, the connecting piece 35 is located close to the end of the corresponding end of the second plastic body 33 , so that there is enough space for the magnetic steel 34 to be placed.

[0054] The relays in this embodiment are a group of normally open relays.

[0055] The present invention employs a subminiature relay with a high creepage distance. The static spring, injection-molded within a first plastic body 23 within a base portion 2, comprises only a normally open static spring blade 24 located at the opposite end of the first plastic body from the coil axis, and a soldering pad 25 located midway along the coil axis, at least for supporting the movable spring-armature assembly. This structure eliminates the normally closed static spring blade from the base portion 2 to increase the creepage distance between the coil terminal 22 and the static spring. This effectively improves the creepage distance between the coil and contacts without increasing the relay's size, thereby meeting the increasingly stringent insulation requirements for relay inputs and outputs in new energy, automotive, and other fields.

[0056] The present invention provides a subminiature relay with a high creepage distance, which is provided with a first groove 232 in the first plastic body 23 in the creepage path between the coil terminal and the soldering station corresponding to the relay input and output (i.e., between the coil and the contact), thereby further improving the creepage distance between the coil and the contact. The present invention also provides a second groove 234 and a second retaining wall 236 in the creepage path between the coil terminal through the iron core 21 and the normally open contact corresponding to the relay input and output (i.e., between the coil and the contact), and utilizes the first retaining wall 235 to allow the creepage path to be transferred from the side wall 231 corresponding to the long side of the rectangle of the first plastic body to the side wall 233 corresponding to the short side of the rectangle of the first plastic body, thereby further improving the creepage distance between the coil and the contact. Figure 5 、 Figure 6 and Figure 8 As shown in the figure, there are two creepage paths between the coil terminal and the normally open contact. One creepage path is from the part of the coil terminal 22 exposed in the first plastic body to the soldering station 25 (because the soldering station is directly connected to the normally open contact). The creepage distance S of this creepage path is from the part of the coil terminal 22 exposed in the first plastic body to the soldering station 25; the other creepage path is from the part of the coil terminal 22 exposed in the first plastic body through the iron core to the normally open contact. The creepage distance of this creepage path is the sum of the distance D1 from the part of the coil terminal 22 exposed in the first plastic body to one end of the iron core 21 and the distance D2 from the other end of the iron core 21 to the normally open contact. Of the two creepage distances, the shorter one is the creepage distance between the coil and the contact of the relay.

[0057] The present invention provides a micro relay with a high creepage distance. The magnet 34 is distributed along the length of the armature, which is also the axis of the coil, and is stacked with the armature 32. The magnet 34 is biased toward one side of the other end of the first plastic body, that is, toward the normally open side of the movable spring. Figures 14 to 16 As shown, the structure of the present invention adopts an unbalanced dual magnetic circuit structure, which makes the normally open end have a greater bias force, avoiding the phenomenon of the relay being difficult to drive or difficult to drive due to the lack of normally closed contact pressure of the seesaw relay, so that the relay can operate reliably. Figure 15 As shown in the figure, when the relay is in the initial state, the magnetic force and the spring reaction force are in the same direction, and the armature restoring force = magnetic force + spring reaction force. However, in the structure of the prior art, there will be contact pressure caused by the normally closed contact overtravel, that is, force = magnetic force + spring reaction force - normally closed contact pressure; Figure 16 As shown, the relay is in working state (normally open contact closed). At this time, the relay is attracted by the coil, while the magnetic force and the reed reaction force are opposite. At this time, force = electromagnetic attraction + magnetic force - reed reaction force - contact pressure.

[0058] The present invention provides a subminiature relay with a high creepage distance. A soldering pad 25 for supporting the soldering lug structure of the movable spring and armature assembly is provided at the common terminal of the first plastic body, without any lead pins. Furthermore, two sets of movable springs 31 are integrally connected at the other side corresponding to the normally open side via a connecting piece 35, and the connecting piece 35 is positioned close to the end of the corresponding end of the second plastic body 33, thereby providing sufficient space for the magnet. This structure of the present invention, such as Figure 18 As shown, two sets of movable springs 31 are electrically connected through a connecting piece 35 to realize the series connection of the normally open contacts. The contact gap is twice the contact gap of the two sets of normally open relays, which can effectively increase the contact gap, the withstand voltage of the disconnected contacts, and the breaking capacity of the product. In this way, the withstand voltage of the contact gap and the distance of the disconnected contact gap can be met without external series wiring.

[0059] Example 2

[0060] See also Figures 19 to 21 As shown, the present invention provides an ultra-small relay with a high creepage distance. This embodiment differs from the first embodiment in that a common terminal lead 251 is provided downwardly at the soldering station 25 of the static spring, exposed outside the first plastic body 23. The common terminal lead 251 is offset toward the other end of the first plastic body 23. This makes the relay of this embodiment a two-group normally open relay.

[0061] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, use the technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent equivalent embodiment. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A subminiature relay with a high creepage distance, comprising a base portion and a movable spring-armature assembly; the base portion comprises a coil, an iron core, a static spring, a coil terminal, and a first plastic body that is assembled into a single piece by injection molding, wherein the coil, the iron core, the static spring, and the coil terminal are completely covered by the first plastic body; pole surfaces at both ends of the iron core protrude from the first plastic body to the upper end of the first plastic body and are respectively located at both ends of the first plastic body, and the portion of the coil terminal exposed from the first plastic body is located at one end of the first plastic body; the movable spring-armature assembly comprises two sets of movable spring leaves, an armature, and a second plastic body that is assembled into a single piece by injection molding, wherein a welding piece structure is provided in the middle of the movable spring-armature assembly, and the movable spring-armature assembly is mounted at a middle position of the top end of the base portion by the welding piece structure so that the two ends of the armature exposed from the second plastic body in the movable spring-armature assembly correspond to the pole surfaces at both ends of the iron core; and the characteristics are: In the base part, the static spring injection-molded in the first plastic body only includes a normally open static spring piece at the other end of the first plastic body and a soldering base corresponding to a soldering piece structure for at least supporting the movable spring armature combination at the middle position of the first plastic body, but no normally closed static spring piece, so as to increase the creepage distance between the coil terminal and the static spring outside the first plastic body by eliminating the normally closed static spring piece; the horizontal cross-section of the first plastic body is rectangular or nearly rectangular; the side wall of the first plastic body corresponding to the long side of the rectangle, and the top end close to one end of the first plastic body is also protruding upward with a first retaining wall, so that the part of the coil terminal exposed to the first plastic body creeps along the side wall of the first plastic body corresponding to the short side of the rectangle through the creepage path between the iron core and the normally open end contact.

2. The ultra-small relay with a high creepage distance according to claim 1, characterized in that: The axis of the coil is arranged horizontally, and the iron core is in a U-shape.

3. The ultra-small relay with a high creepage distance according to claim 1 or 2, characterized in that: A welding piece structure is respectively provided on both sides of the middle of the movable spring-armature combination, and the two welding piece structures are respectively integrated into a corresponding group of movable spring pieces and exposed outside the second plastic body; the movable spring piece is an asymmetric structure relative to the welding piece structure, and the movable spring piece is provided with a normally open side exposed outside the second plastic body on the side corresponding to the normally open static spring piece, and the normally open side of the movable spring piece is equipped with a normally open movable contact; the other side of the movable spring piece opposite to the normally open side is completely covered in the second plastic body.

4. The ultra-small relay with a high creepage distance according to claim 1, wherein: The horizontal cross-section of the first plastic body is rectangular or nearly rectangular, and a first groove is provided at the side wall of the first plastic body corresponding to the long side of the rectangle, corresponding to the creepage path between the portion of the coil terminal exposed in the first plastic body and the soldering pad exposed in the first plastic body, so as to utilize the first groove to increase the creepage distance between the portion of the coil terminal exposed in the first plastic body and the soldering pad.

5. The ultra-small relay with a high creepage distance according to claim 1, wherein: A second groove is provided on the side wall of the first plastic body corresponding to the short side of the rectangle, corresponding to the creepage path between the portion of the coil terminal exposed from the first plastic body and one end of the iron core, so as to utilize the second groove to increase the creepage distance between the portion of the coil terminal exposed from the first plastic body through the iron core and the normally open contact.

6. The ultra-small relay with a high creepage distance according to claim 5, characterized in that: A second retaining wall is provided at the upper end of the first plastic body in the creepage path corresponding to the other end of the iron core and the normally open contact, so as to utilize the second retaining wall to further increase the creepage distance between the part of the coil terminal exposed from the first plastic body through the iron core and the normally open contact.

7. The ultra-small relay with a high creepage distance according to claim 3, characterized in that: The movable spring-armature assembly further includes a magnetic steel, which is distributed along the length direction of the armature and stacked with the armature, and the magnetic steel is biased toward the other end of the first plastic body.

8. The ultra-small relay with a high creepage distance according to claim 7, characterized in that: In the movable spring piece, a common end lead-out pin exposed outside the first plastic body is further downwardly provided at the soldering station, and the common end lead-out pin is biased toward the other end of the first plastic body.

9. The ultra-small relay with a high creepage distance according to claim 7, characterized in that: The two sets of dynamic springs are electrically connected at the other side corresponding to the normally open side via a connecting piece, and the connecting piece is completely enclosed in the second plastic body; the connecting piece is integrally connected to the two sets of dynamic springs by integral molding, or the connecting piece is a separate part, and the two ends of the connecting piece are respectively connected to the two sets of dynamic springs by overlapping or welding.

10. The subminiature relay with a high creepage distance according to claim 9, characterized in that: The connecting piece is close to the end position of the corresponding end of the second plastic body, so that there is enough space for placing the magnetic steel.

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