Bridge type single-pole double-throw microswitch

Abstract

The application discloses a bridge type single-pole double-throw microswitch, which comprises a shell and a button, the button is arranged on the top of the shell, the button is fixedly connected with one end of a push rod, the other end of the push rod is arranged in a reset spring, and a limiting seat is symmetrically fixed to the inner side walls of the shell; upper and lower ends of both sides in the shell are provided with upper contact points and lower contact points, the upper contact points and the lower contact points are extended to the bottom of the shell outside through long guide rods and short guide rods, a moving contact point is arranged between the upper contact points and the lower contact points, the upper contact points and the lower contact points are correspondingly arranged on the upper side and the lower side of the moving contact point respectively, the moving contact point is fixedly connected with a reed through a push rod, a tension spring is sleeved on the reed, one end of the tension spring is connected with the push rod, and the other end of the tension spring is connected with the middle part of the reed. Through the rigid connection of the push rod and the moving contact point assembly and the elastic constraint of the reset spring and the tension spring, the action response of the moving contact point assembly is ensured to be rapid, the action synchronization of the moving contact point assembly and a main contact point of a contactor is high, and the interlocking control requirement is met.

Description

Technical Field

[0001] This invention relates to a bridge-type single-pole double-throw micro switch. Background Technology

[0002] As a core actuator in aviation electrical systems, contactors perform critical functions such as main power supply switching and motor control. Their internal auxiliary contacts must meet requirements for status feedback and interlocking control, and face stringent demands regarding the synchronization of main contact actions, compact design, and long-term reliability. Existing microswitches suffer from narrow load adaptability, poor adaptability to complex environments, and short contact life, making it difficult to meet the reliable operation requirements of contactor internal auxiliary contacts under currents ranging from 0.1mA to 5A and load voltages up to 28V, and also unable to adapt to the complex testing environments of aviation scenarios. Therefore, developing a microswitch that combines wide load capacity, high synchronization, compact structure, and long lifespan is crucial for filling the application gap in complex scenarios. Summary of the Invention

[0003] The purpose of this invention is to provide a bridge-type single-pole double-throw micro switch to address the problems of poor synchronization of contact actions and poor space compactness in existing devices.

[0004] The technical solution of the present invention: A bridge-type single-pole double-throw micro switch includes a housing and a button. The button is located on the top of the housing and is fixedly connected to one end of a push rod. The other end of the push rod is placed inside a return spring. Limit seats are symmetrically fixed to the inner side walls of the housing. Upper and lower contacts are installed at the upper and lower ends of both sides of the housing. The upper and lower contacts extend to the bottom of the housing through a long guide rod and a short guide rod, respectively. A moving contact is provided between the upper and lower contacts, and the upper and lower contacts are respectively arranged corresponding to the upper and lower sides of the moving contact. The moving contact is fixedly connected to the push rod by a spring. A tension spring is fitted outside the spring, with one end of the tension spring connected to the push rod and the other end connected to the middle of the spring.

[0005] The outer casing has mounting holes on its side wall.

[0006] The top of the button protrudes from a through-hole at the center of the top of the housing.

[0007] The upper and lower contacts are made of silver cadmium oxide, and the contact surfaces are plated with a gold plating layer.

[0008] The initial contact distance between the upper contact and the moving contact assembly, and between the lower contact and the moving contact assembly, is ≥0.4mm.

[0009] A limiting seat is installed at the bottom of the outer shell, and the limiting seat and the outer shell are sealed by DG-3S epoxy adhesive.

[0010] The moving contact assembly has a travel of 1.6 mm and a driving force F of 1.2 N to 3.5 N.

[0011] The long and short guide rods are used to transmit electrical signals and are compatible with a current range of 0.1mA to 5A and a load voltage of 28VDC.

[0012] The beneficial effects of this invention are as follows: The rigid connection between the push rod and the moving contact assembly, along with the elastic constraints of the return spring and tension spring, ensures rapid response of the moving contact assembly and high synchronization with the main contact of the contactor, meeting interlocking control requirements. The upper and lower contacts are made of silver cadmium oxide and gold-plated. Combined with the conductive design of long and short guide rods, it can adapt to a current range of 0.1mA to 5A and a load voltage of 28V DC. It exhibits stable contact resistance and excellent resistance to electrical wear. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention.

[0014] Figure 2 This is a schematic diagram of the contact principle of the present invention.

[0015] Figure 3 This is a schematic diagram of the contact structure of the present invention.

[0016] Figure 4 This is a schematic diagram of the outer shell structure of the present invention.

[0017] In the diagram: 1-Button, 2-Housing shell, 3-Long guide rod, 4-Upper contact, 5-Tension spring, 6-Moving contact, 7-Lower contact, 8-Short guide rod, 9-Push rod, 10-Mounting hole, 11-Reset spring, 12-Limit seat. Detailed Implementation

[0018] The micro switch structure described in this invention mainly consists of three parts. The first part is a base, used to position other components and ensure contact gaps. The second part is an actuation system, composed of a moving contact assembly, a button, a positioning clip, and a spring. When the button is subjected to an external force F, it drives the moving contact assembly to shift, causing the contacts to switch and thus connecting the load circuit. The third part consists of a long conductive rod and a short conductive rod, used to transmit electrical signals.

[0019] like Figure 1 As shown, button 1 is located on the top of housing 2 as the end of external force application; push rod 9 is a rigid rod, one end of which is fixedly connected to button 1, and the other end is placed in the return spring. The middle part is fixedly connected to moving contact 6 through spring sheet to realize the transmission of external force.

[0020] The reset spring 11 is used to drive the button 1 and the push rod 9 to reset after the external force is removed.

[0021] Two tension springs 5 ​​are provided. One end of each tension spring 5 is connected to the push rod, and the other end is connected to the middle of the spring plate. They are used to limit the offset of the moving contact assembly 6 and assist its reset.

[0022] Both the long guide rod 3 and the short guide rod 8 are made of conductive material and are vertically fixed to both sides inside the outer casing 2, and are arranged in parallel. The top of the long guide rod 3 is processed into a vertical bend and an upper contact 4 is fixedly installed on the lower end face of the bend. The top of the short guide rod 8 is processed into a vertical bend and a lower contact 7 is fixedly installed on the upper end face of the bend. The upper contact 4 and the lower contact 7 are symmetrically distributed in the vertical direction and correspond to the upper and lower surfaces of the moving contact 6, respectively, forming the core contact structure for circuit opening and closing.

[0023] The housing 2 has symmetrical mounting holes 10 on its side wall for fixing the micro switch to a preset position inside the contactor; the housing 2 and the internal base adopt a snap-fit ​​structure, and the contact parts are sealed with DG-3S epoxy adhesive.

[0024] The appropriate selection of contact materials has a significant impact on the reliability and lifespan of relays. For microswitches, the general requirements for contact materials are good electrical and thermal conductivity, low resistivity, stable contact resistance, good resistance to electrical wear, and good processability. Currently, silver-based alloys are mostly used for contact materials in aviation applications. Among them, AgCuO (silver copper oxide), AgCdO (silver cadmium oxide), and AgSnO2(7)In2O3(3) (silver tin oxide indium oxide) are widely used in the industry. Based on the actual application, silver cadmium oxide AgCdO(10) is selected. This material has good resistance to welding and arc erosion, low and stable contact resistance, and good processability for both moving and stationary contacts. Figure 3 .

[0025] Currently, the size and parameters of contacts are mainly determined by empirical formulas. Influenced by factors such as space, load size, and contact method, their structural forms are diverse, making it difficult to provide a complete set of design formulas and procedures. In practical engineering design, sufficient cross-section or heat dissipation surface must be considered. The contact diameter dk is generally calculated using empirical formulas. Where: c1——engineering coefficient, c1 takes the value of 0.6~0.8mm·(A)-1, for planar contact type contact c1=0.6 (the contact model is point-to-surface contact that gradually wears down to surface-to-surface contact); Ik——Rated current, Ik=5A.

[0026] The contact diameter dk is calculated to be approximately 1.34 mm using the formula. The diameter of the stationary contact is designed to be 3.2 mm, which meets the requirements. The contact morphology is shown in [reference needed]. Figure 3 , The internal structure of the product's outer casing is matched with the base structure to ensure a tight and secure fit. After assembly, to secure the product and enhance sealing, DG-3S adhesive is applied to the contact areas between the casing and the base. Baking is required after adhesive application to ensure the product is firmly secured. DG-3S adhesive is an epoxy adhesive with a temperature range of -60℃ to 150℃, meeting product usage requirements and providing a 10-15 year service life after curing. See the outer casing structure section for details. Figure 4 .

[0027] The contacts should reliably interrupt the arc under the maximum switching load of 28V DC 5A, based on the empirical formula for arc breaking length: In the formula: k—the arc coefficient under different atmospheres; in air, k=0.012. U—Load voltage; I — Load current.

[0028] The internal contact material of the product is silver cadmium oxide AgCd0 (10). This material generates a violent arc blowing effect under the action of high temperature electric arc, which significantly reduces the arc energy and shortens the arc burning time. In addition, the contact surface is plated with gold to increase the anti-arc performance. Considering the contact situation, in order to ensure that the product can reliably interrupt the arc, the contact spacing is designed to be greater than or equal to 0.25mm. The contact spacing of the product is designed to be ≥0.4mm, which fully meets the requirements.

[0029] The main technical specifications of the bridge-type single-pole double-throw micro switch described in this invention are shown in Table 1.

[0030] Table 1 Performance Indicators

Claims

1. A bridge-type single-pole double-throw micro switch, characterized in that: Includes a housing (2) and a button (1). The button (1) is located on the top of the housing (2). The button (1) is fixedly connected to one end of the push rod (9). The other end of the push rod (9) is placed inside the reset spring (11). The limiting seat (12) is symmetrically fixed to the two inner walls of the housing (2). The upper and lower ends of the inner sides of the housing (2) are equipped with upper contacts (4) and lower contacts (7). The upper contacts (4) and lower contacts (7) extend to the bottom of the housing (2) through the long guide rod (3) and the short guide rod (8), respectively. A moving contact (6) is provided between the upper contacts (4) and the lower contacts (7). The upper contacts (4) and the lower contacts (7) are respectively set to the upper and lower sides of the moving contact (6). The moving contact (6) is fixedly connected to the push rod (9) through a spring. A tension spring (5) is fitted on the outside of the spring. One end of the tension spring (5) is connected to the push rod (9), and the other end is connected to the middle of the spring.

2. The bridge-type single-pole double-throw micro switch as described in claim 1, characterized in that: The outer casing (2) has mounting holes (10) on its side wall.

3. The bridge-type single-pole double-throw micro switch as described in claim 1, characterized in that: The top of the button (1) protrudes from the through hole at the center of the top of the housing (2).

4. The bridge-type single-pole double-throw micro switch as described in claim 1, characterized in that: The upper contact (4) and lower contact (7) are made of silver cadmium oxide and are plated with a gold plating layer.

5. The bridge-type single-pole double-throw micro switch as described in claim 1, characterized in that: The initial contact distance between the upper contact (4) and the moving contact assembly (6), and between the lower contact (7) and the moving contact assembly (6), is ≥0.4mm.

6. The bridge-type single-pole double-throw micro switch as described in claim 1, characterized in that: The bottom of the outer shell (2) is fitted with a limiting seat (12), and the limiting seat (12) and the outer shell (2) are sealed by DG-3S epoxy adhesive.

7. The bridge-type single-pole double-throw micro switch as described in claim 1, characterized in that: The moving contact assembly (6) has a stroke of 1.6 mm and a driving force F of 1.2 N to 3.5 N.

8. The bridge-type single-pole double-throw micro switch as described in claim 1, characterized in that: The long guide rod (3) and the short guide rod (8) are used to transmit electrical signals and are adapted to a current range of 0.1mA to 5A and a load voltage of 28VDC.

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