Patch inductor applied to automotive electronic lighting system

Abstract

The utility model relates to the field of patch inductance, concretely relates to a kind of patch inductance applied to automotive electronic lighting system, including core, coil, two electrode pieces and shield case, shield case has the cylindrical cavity that penetrates its line lower end face, this shield case is along the axis of core and is set in the outside of core from the cover of core, and the upper end face of shield case is flush with the upper end face of core;Cavity inner wall is uniformly distributed with four radially extending strip grooves around its circumference, each electrode piece integrally has the connecting portion for being connected with the end portion of winding that extends into strip groove;The upper end position in cavity is filled with caulking glue between cavity inner wall and upper magnetic plate;Shield case is formed by iron powder mixed glue water pressing. The shield case formed by iron powder mixed glue water pressing solves the defect of insufficient magnetic shielding of patch inductance in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of surface mount inductors, specifically to a surface mount inductor used in automotive electronic lighting systems. Background Technology

[0002] In automotive electronic lighting systems, the insufficient magnetic shielding effectiveness of surface-mount inductors has become a core bottleneck restricting the system's electromagnetic compatibility (EMC). From an electromagnetic theory perspective, traditional surface-mount inductors generally employ open or semi-open-loop core designs, whose magnetic circuit structures cannot form closed magnetic flux paths, resulting in significant leakage of magnetic field lines. Actual measurement data shows that the leakage rate of a typical open-loop core design can be as high as 35%. This unconstrained magnetic field can interfere with surrounding sensitive electronic components in the form of electromagnetic interference (EMI).

[0003] Insufficient magnetic shielding leading to EMI issues is particularly prominent in the high-density integrated environment of automotive electronics. The physical distance between the headlight control module (ECU) and key components such as millimeter-wave radar and in-vehicle communication systems is typically less than 10 cm, making inductor leakage prone to creating cross-interference "hot spots." Real-world testing data from a car manufacturer shows that magnetic field leakage in traditional surface-mount inductors in the headlight ECU increased the false detection rate of adjacent millimeter-wave radars by 27%, primarily manifesting as incorrect identification of static obstacles. 19 Similarly, the EMI radiation intensity of traditional surface-mount inductors in wireless charging pile systems exceeds 40 dBμV / m, directly interfering with the signal reception sensitivity of in-vehicle Bluetooth and Wi-Fi communication modules.

[0004] In view of the shortcomings of the existing technology, this application aims to provide a surface mount inductor with good magnetic shielding effect. Utility Model Content

[0005] To address the aforementioned issues, a surface mount inductor for automotive electronic lighting systems is provided. This inductor overcomes the deficiency of insufficient magnetic shielding in existing surface mount inductors by using a shielding cover formed by pressing iron powder mixed with adhesive.

[0006] To address the problems of existing technologies, this utility model provides a surface mount inductor for use in automotive electronic lighting systems, comprising: The iron core has an I-shaped structure, including an upper magnetic plate, a central shaft, and a lower magnetic plate; The coil is wound around the central axis of the iron core; The electrode plate has two electrodes, which are disposed at the bottom of the lower magnetic plate; The shield has a cylindrical cavity extending through its lower end face. The shield is installed on the outside of the iron core from bottom to top along the axis of the iron core, and the upper end face of the shield is flush with the upper end face of the iron core. The inner wall of the cavity is evenly distributed with four radially extending strip grooves around its circumference. Each electrode sheet is integrally formed with a connection portion extending into the strip groove for connecting with the end of the coil. The upper part of the cavity is located between the inner wall of the cavity and the upper magnetic plate, and is filled with sealant. The shielding cover is formed by pressing iron powder and sintering it at high temperature.

[0007] Preferably, the electrode sheet and the lower magnetic plate are connected by adhesive.

[0008] Preferably, the shield has a square cross-section along the axial direction of the chamber, and the bottom of the shield has a notch in each of the four directions. Each electrode plate has a pin extending into one of the notches.

[0009] Preferably, the design dimension of the cross-section side length is 7.3 mm, with a tolerance of 0.2 mm.

[0010] Preferably, the maximum distance from the top of the shield to the bottom of the pin is 4.5 mm.

[0011] Preferably, the nominal inductance of the patch inductor is 220μH, with an allowable deviation range of ±20%.

[0012] Preferably, the operating temperature range of the surface mount inductor is -40°C to 125°C.

[0013] Compared with the prior art, the advantages of this utility model are: the shielding cover pressed by iron powder mixed with glue forms a closed magnetic circuit, which, together with the strip groove on the inner wall of the cavity and the sealant on the top, reduces the leakage magnetic field and electromagnetic radiation. Attached Figure Description

[0014] Figure 1 This is a three-dimensional view of a surface-mount inductor used in an automotive electronic lighting system according to this utility model.

[0015] Figure 2 This is a top view of a surface-mount inductor used in an automotive electronic lighting system according to this utility model.

[0016] Figure 3 This is a side view of a surface mount inductor used in an automotive electronic lighting system according to this utility model.

[0017] Figure 4 yes Figure 2 A cross-sectional view along the AA direction.

[0018] Figure 5 yes Figure 2 A cross-sectional view along the BB direction.

[0019] Figure 6This is a three-dimensional cross-sectional view of a surface-mount inductor used in an automotive electronic lighting system according to this utility model.

[0020] Figure 7 This is a three-dimensional exploded view of a surface-mount inductor used in an automotive electronic lighting system, according to this utility model.

[0021] The numbers in the diagram are: 1. Iron core; 11. Upper magnetic plate; 12. Central shaft; 13. Lower magnetic plate; 2. Coil; 3. Electrode plate; 31. Connecting part; 32. Pin; 4. Shielding cover; 41. Chamber; 42. Strip groove; 5. Sealant. Detailed Implementation

[0022] To further understand the features, technical means, and specific objectives and functions achieved by this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments.

[0023] See Figures 1-7 As shown, the surface mount inductor used in an automotive electronic lighting system includes: an iron core 1, which has an I-shaped structure and includes an upper magnetic plate 11, a central shaft 12, and a lower magnetic plate 13; a coil 2, wound around the central shaft 12 of the iron core 1; two electrode plates 3, which are disposed at the bottom of the lower magnetic plate 13; a shield 4, which has a cylindrical cavity 41 extending through its lower end face, the shield 4 covering the outside of the iron core 1 from the axis downwards, and the upper end face of the shield 4 is flush with the upper end face of the iron core 1; the inner wall of the cavity 41 has four radially extending strip grooves 42 evenly distributed around its circumference, and each of the electrode plates 3 is integrally formed with a connecting part 31 extending into the strip groove 42 for connecting with the end of the coil 2; the upper end of the cavity 41, located between the inner wall of the cavity 41 and the upper magnetic plate, is filled with sealant 5; the shield 4 is formed by pressing iron powder and sintering at high temperature.

[0024] The electrode sheet 3 is connected to the lower magnetic plate 13 by adhesive.

[0025] The shield 4 has a square cross-section along the axial direction of the chamber 41. The bottom of the shield 4 has a notch in each of the four directions. Each electrode plate 3 has a pin 32 extending into a notch.

[0026] In terms of dimensions, the design dimension of the cross-section side length is 7.3mm, with a tolerance of 0.2mm. The maximum distance from the top of the shield 4 to the bottom of the pin 32 is 4.5mm.

[0027] In terms of performance: Inductance L: The nominal inductance is 220μH, with an allowable deviation range of ±20%, and a reference value of 221μH.

[0028] Load inductance L: The maximum limit is a 10% decrease in inductance at 0.7A current, with a reference value of 212μH.

[0029] Load inductance L: At a current of 0.77A, the maximum limit is a 30% decrease in inductance; the reference value is 208μH. DC resistance (DCR): The maximum DC resistance is 1.25Ω, and the reference value is 1.08mΩ.

[0030] Saturation current Isat MAX: When the peak saturation current is 0.7A, the inductance value L will decrease by no more than 10% at most. Saturation current IsatMAX: When the peak saturation current is 0.77A, the inductance value L will decrease by no more than 30%. Temperature rise current I rms MAX: When the effective value of the temperature rise current is 0.85A, it will cause the product temperature ΔT to rise by a maximum of 40°C. Inductor turns: 77.5 turns (reference) Operating temperature: The operating temperature range is -40℃ to 125℃. Under operating conditions, the product temperature (ambient temperature + temperature rise) should not exceed 125℃.

[0031] The above embodiments only illustrate one or more implementations of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.

Claims

1. Surface mount inductors used in automotive electronic lighting systems, including: The iron core (1) has an I-shaped structure, including an upper magnetic plate (11), a central shaft (12) and a lower magnetic plate (13). The coil (2) is wound around the central axis (12) of the iron core (1); Two electrode plates (3) are provided at the bottom of the lower magnetic plate (13); The shield (4) has a cylindrical cavity (41) extending through its lower end face. The shield (4) is installed on the outside of the iron core (1) from bottom to top along the axis of the iron core (1), and the upper end face of the shield (4) is flush with the upper end face of the iron core (1). Its features are, The inner wall of the chamber (41) is evenly distributed with four radially extending strip grooves (42) around its circumference. Each electrode sheet (3) is integrally formed with a connecting part (31) extending into the strip groove (42) and used to connect with the end of the coil (2). The upper part of the cavity (41) is located between the inner wall of the cavity (41) and the upper magnetic plate and is filled with sealant (5). The shield (4) is formed by pressing iron powder and sintering it at high temperature.

2. The surface mount inductor for automotive electronic lighting systems according to claim 1, characterized in that, The electrode sheet (3) is connected to the lower magnetic plate (13) by glue.

3. The surface mount inductor for automotive electronic lighting systems according to claim 1 or 2, characterized in that, The shield (4) has a square cross-section along the axial direction of the chamber (41), and the bottom of the shield (4) has a notch in each of the four directions. Each electrode plate (3) has a pin (32) extending into a notch.

4. The surface mount inductor for automotive electronic lighting systems according to claim 3, characterized in that, The design dimension of the cross-section side length is 7.3mm, with a tolerance of 0.2mm.

5. The surface mount inductor for automotive electronic lighting systems according to claim 4, characterized in that, The maximum distance from the top of the shield (4) to the bottom of the pin (32) is 4.5 mm.

6. The surface mount inductor for automotive electronic lighting systems according to claim 1, characterized in that, The nominal inductance of this surface mount inductor is 220μH, with a tolerance range of ±20%.

7. The surface mount inductor for automotive electronic lighting systems according to claim 1, characterized in that, The operating temperature range of this surface mount inductor is -40°C to 125°C.

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