Pedal displacement sensor circuit board assembly

Abstract

The utility model discloses a pedal displacement sensor circuit board assembly comprising a circuit board, one end of the circuit board is provided with a bonding pad, and the bonding pad is welded with an L-shaped terminal; the end face of the bonding pad is divided into different tin-coated areas through a green oil layer, the tin-coated areas comprise a first tin-coated area and a second tin-coated area, and the tin-coated areas are coated with tin paste layers. According to the utility model, the middle of the gold immersion pad welded with the L-shaped terminal on the circuit board is divided into different tin coating areas by the green oil layer, so that solder paste on the pad is prevented from excessively climbing to the contact end face of the L-shaped terminal after secondary reflow soldering. The first tin coating area is controlled by a steel mesh to coat the whole area with solder paste, and the welding strength of the circuit board and the L-shaped terminal can be improved after one-time reflow soldering; the second tin coating area is controlled by the steel mesh to be coated with the solder paste in partial area, after secondary reflow soldering, the welding strength of the circuit board and the L-shaped terminal can be improved, excessive tin climbing can be prevented, and the cost of the reflow soldering process can be effectively reduced by reducing the coating amount of the solder paste.

Description

Technical Field

[0001] The utility model relates to the technical field of pedal displacement sensors, in particular to a pedal displacement sensor circuit board assembly. Background Art

[0002] The electronically controlled brake system is a modern automobile braking system that controls the pressure and force of the brake system through an electronic control unit to provide more precise and efficient braking performance. Compared with the traditional hydraulic brake system, it has a higher response speed, better braking performance and stronger stability. It can adjust the braking force in real time according to different driving conditions and road conditions, improving driving safety and comfort. The pedal displacement sensor is an important part of the electronically controlled brake system. Its function is to monitor the pedal force and position of the brake pedal, and convert the driver's operation of the pedal into an electrical signal to adjust the vehicle's power output or braking force according to the driver's operation.

[0003] In existing pedal displacement sensors, the reflow process is usually used to solder the circuit board terminals. After the L-shaped terminal undergoes secondary reflow, excessive soldering may occur, resulting in poor contact between the terminal end face and the end cover assembly, thus affecting the normal operation of the sensor. When the amount of solder in the soldering process is controlled to prevent excessive soldering, the soldering strength between the L-shaped terminal and the circuit board may be reduced, resulting in the risk of the terminal end face and the end cover assembly falling off during long-term press-fitting. Utility Model Content

[0004] The purpose of the utility model is to solve the above problems and provide a pedal displacement sensor circuit board assembly.

[0005] In order to achieve the above-mentioned purpose, the utility model specifically adopts the following technical solutions, including:

[0006] A circuit board, wherein a pad is provided at one end of the circuit board, and an L-shaped terminal is welded to the pad;

[0007] The pad end surface is divided into different tin-coated areas by a green oil layer, and the tin-coated areas include a first tin-coated area and a second tin-coated area, and the tin-coated areas are coated with a tin paste layer.

[0008] As a further description of the above technical solution, the soldering pads are arranged on the front and back sides of the circuit board, and the soldering pads are symmetrically distributed in 3 groups.

[0009] As a further description of the above technical solution, the pad is a gold-immersion PCB pad, and the length of the pad is half the length of the end of the circuit board.

[0010] As a further description of the above technical solution, the area of ​​the first tin-coated area is 50%-60% of the area of ​​the tin-coated region.

[0011] As a further description of the above technical solution, the area of ​​the second tin-coated area is 40%-50% of the area of ​​the tin-coated region.

[0012] As a further description of the above technical solution, the area of ​​the green oil layer is 20% of the area of ​​the tin-coated region.

[0013] As a further description of the above technical solution, the first tin-coated area is entirely coated with a tin paste layer.

[0014] As a further description of the above technical solution, a region of the second tin-coated area close to the green oil is coated with a tin paste layer.

[0015] As a further description of the above technical solution, the area of ​​the second tin-coated area coated with the solder paste layer is 20%-40% of the area of ​​the second tin-coated area.

[0016] As a further description of the above technical solution, the thickness of the solder paste layer in the tin-coated area is 0.1-0.15 mm.

[0017] The beneficial effects of the utility model are as follows:

[0018] 1. In the utility model, the middle of the immersion gold pad on the circuit board that is welded to the L-shaped terminal is separated into different tin-coated areas by a green oil layer to prevent the solder paste on the pad from excessively creeping onto the contact end face of the L-shaped terminal after the second reflow. The first tin-coated area is controlled by a steel mesh to coat the solder paste in the entire area, which can increase the welding strength between the circuit board and the L-shaped terminal after one reflow; the second tin-coated area is controlled by a steel mesh to coat the solder paste in a partial area, which can increase the welding strength between the circuit board and the L-shaped terminal after the second reflow and prevent excessive solder creeping, and reducing the amount of solder paste coating can effectively reduce the cost of the reflow process.

[0019] In order to more clearly illustrate the structural features and functions of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of poor contact of L-shaped terminals in an existing circuit board assembly after excessive solder creep;

[0021] Figure 2 It is a schematic diagram of the L-shaped terminal in the existing circuit board assembly falling off after the tin amount is reduced;

[0022] Figure 3 It is a structural schematic diagram of the circuit board assembly of the utility model;

[0023] Figure 4 This is a schematic diagram of the structure of the tin-coated area of ​​the circuit board of the utility model. Figure 1 ;

[0024] Figure 5 This is a schematic diagram of the structure of the tin-coated area of ​​the circuit board of the utility model. Figure 2 ;

[0025] Figure 6 This is a schematic diagram of the structure of the tin-coated area of ​​the circuit board of the utility model. Figure 3 ;

[0026] Figure 7 This is a schematic diagram of the secondary reflow soldering after mounting the L-shaped terminal of the utility model. Figure 1 ;

[0027] Figure 8 This is a schematic diagram of the secondary reflow soldering after mounting the L-shaped terminal of the utility model. Figure 2 ;

[0028] Fig. 9 yes Figure 8 An enlarged schematic diagram of .

[0029] Reference numerals:

[0030] 1. Circuit board; 2. Solder pad; 21. Tin-coated area; 211. First tin-coated area; 212. Second tin-coated area; 3. L-shaped terminal; 4. Green oil layer; 5. Solder paste layer. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present utility model clearer, the technical solution in the embodiments of the present utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the present utility model.

[0032] like Figure 1-Figure 9 As shown, in one embodiment, a pedal displacement sensor circuit board assembly includes: a circuit board, a solder pad is provided at one end of the circuit board, and an L-shaped terminal is welded to the solder pad. Specifically, the solder pad is provided on both sides of the circuit board, and the solder pad is symmetrically distributed in three groups. The solder pad adopts an immersion gold PCB solder pad, and the length of the solder pad is half the length of the end of the circuit board.

[0033] like Figure 1-Figure 9 As shown, in this embodiment, the end surface of the pad is divided into different tin-coated areas by a green oil layer. Among them, the tin-coated area includes a first tin-coated area and a second tin-coated area, and the first tin-coated area is entirely coated with a tin paste layer. The area of ​​the second tin-coated area close to the green oil is coated with a tin paste layer. Specifically, the area of ​​the first tin-coated area accounts for 50%-60% of the area of ​​the tin-coated area, and the area of ​​the second tin-coated area accounts for 40%-50% of the area of ​​the tin-coated area; the area of ​​the green oil layer accounts for 20% of the area of ​​the tin-coated area; in the second tin-coated area, the area of ​​the tin paste layer accounts for 20% to 40% of the area of ​​the second tin-coated area. The thickness of the tin paste layer in these tin-coated areas is 0.1-0.15mm.

[0034] The specific process steps include:

[0035] (1) In the circuit board assembly of the pedal displacement sensor, the middle of the immersion gold pad on the circuit board that is soldered to the L-shaped terminal is separated into different tin-coated areas by a green oil layer, so that the tin in the first tin-coated area will not flow to the second tin-coated area during the reflow soldering process; (e.g. Figure 4 shown);

[0036] (2) In an automatic coating machine, the solder paste is printed and coated on the entire area of ​​the first tin coating area through the opened steel mesh, and the solder paste is coated on part of the second tin coating area, so that after the solder paste flows, it can not only fully weld the L-shaped terminal but also will not excessively climb to the contact end surface of the L-shaped terminal, thereby increasing the welding strength between the circuit board and the L-shaped terminal (such as Figure 5 and Figure 6 shown);

[0037] (3) Use a bonding machine to attach three L-shaped terminals to the corresponding pad positions on the front of the circuit board for a reflow soldering process and then pass through a high-temperature furnace, so that the L-shaped terminals on the circuit board have a strong welding strength with the circuit board after the high-temperature furnace (such as Figure 7 and Figure 8 shown);

[0038] (4) Use a mounting machine to attach the other three L-shaped terminals to the corresponding pad positions on the back of the circuit board for secondary reflow soldering and then pass through a high-temperature furnace, so that there is no excessive solder creeping to the contact end surface of the L-shaped terminal on the circuit board after two high-temperature furnaces, which can increase the welding strength between the circuit board and the L-shaped terminal and prevent excessive solder creeping (such as Figure 7 and Figure 8 shown).

[0039] Through the above technical scheme, in order to prevent the solder paste on the pad from excessively creeping onto the contact end face of the L-shaped terminal after the second reflow soldering, the present application uses a green oil layer to separate the middle of the immersion gold pad soldered to the L-shaped terminal on the circuit board into different tin-coated areas: the first tin-coated area is controlled by a steel mesh to coat the solder paste in the entire area, which can increase the welding strength between the circuit board and the L-shaped terminal after one reflow soldering; and the second tin-coated area is controlled by a steel mesh to coat the solder paste in a partial area, which can increase the welding strength after the second reflow soldering, and can effectively prevent the problem of excessive tin creeping, and reduce the amount of solder paste coating, which can effectively reduce the cost of the reflow soldering process.

[0040] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pedal displacement sensor circuit board assembly, characterized in that: include: A circuit board (1), wherein a soldering pad (2) is provided at one end of the circuit board (1), and an L-shaped terminal (3) is welded to the soldering pad (2); The end surface of the solder pad (2) is divided into different tin-coated areas (21) by a green oil layer (4), the tin-coated areas (21) include a first tin-coated area (211) and a second tin-coated area (212), and the tin-coated areas (21) are coated with a solder paste layer (5).

2. The pedal displacement sensor circuit board assembly according to claim 1, characterized in that: The soldering pads (2) are arranged on the front and back sides of the circuit board (1), and three groups of the soldering pads (2) are symmetrically distributed.

3. The pedal displacement sensor circuit board assembly according to claim 1, characterized in that: The pad (2) is a gold-immersion PCB pad (2), and the length of the pad (2) is half the length of the end of the circuit board (1).

4. The pedal displacement sensor circuit board assembly according to claim 1, characterized in that: The area of ​​the first tin-coated area (211) is 50%-60% of the area of ​​the tin-coated region (21).

5. The pedal displacement sensor circuit board assembly according to claim 1, characterized in that: The area of ​​the second tin-coated region (212) is 40%-50% of the area of ​​the tin-coated region (21).

6. The pedal displacement sensor circuit board assembly according to claim 1, characterized in that: The area of ​​the green oil layer (4) is 20% of the area of ​​the tin-coated region (21).

7. The pedal displacement sensor circuit board assembly according to claim 1, characterized in that: The first tin-coated area (211) is entirely coated with a tin paste layer (5).

8. The pedal displacement sensor circuit board assembly according to claim 1, characterized in that: The area of ​​the second tin-coated area (212) close to the green oil is coated with a tin paste layer (5).

9. The pedal displacement sensor circuit board assembly according to claim 1, characterized in that: The area of ​​the second tin-coated area (212) coated with the tin paste layer (5) is 20%-40% of the area of ​​the second tin-coated area (212).

10. The pedal displacement sensor circuit board assembly according to claim 1, characterized in that: The thickness of the solder paste layer (5) in the tin-coated area (21) is 0.1-0.15 mm.

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