WO2021047272A1

WO2021047272A1 - Vehicle-mounted charger and field effect transistor installation method therefor

Info

Publication number: WO2021047272A1
Application number: PCT/CN2020/101121
Authority: WO
Inventors: 刘钧; 冯颖盈; 姚顺; 郭珏; 廖俊锋
Original assignee: 深圳威迈斯新能源股份有限公司
Priority date: 2019-09-09
Filing date: 2020-07-09
Publication date: 2021-03-18
Also published as: CN110545632A

Abstract

Disclosed are a vehicle-mounted charger and a field effect transistor (FET) installation method therefor, wherein a housing of the vehicle-mounted charger is provided with an accommodation cavity and a coolant flow channel disposed in the accommodation cavity. The FET installation method comprises the following steps: step 1, installing several FETs on a bracket, and fixing the bracket onto a circuit board; step 2, loading the side of the circuit board fixed with the bracket facing downwards in the accommodation cavity of the housing, so that the bracket is located at one side of the coolant flow channel and the FETs are located between the bracket and the coolant flow channel; step 3, attaching the FETs onto a sidewall of the coolant flow channel; step 4, soldering pins of the FETs onto the circuit board. In the present invention, the standardization and degree of automation of the production process are high, which may save manual resources and increase production efficiency.

Description

Vehicle-mounted charger and its field effect tube installation method

Technical field

The invention relates to the technical field of the production process of a vehicle-mounted charger, in particular to a vehicle-mounted charger and a field effect tube installation method thereof.

Background technique

With the demand for energy saving, emission reduction and control of air pollution, new energy vehicles (pure electric and hybrid vehicles) are becoming the new main force in the automotive industry and are developing rapidly. Wireless chargers used in automobiles have also emerged and gradually matured. The field effect tube is an indispensable important electronic component in the on-board charger.

At present, the usual installation methods of FETs in the power supply industry are as follows:

Method one (manual fixing, manual soldering): The first step is to manually hold the FET on the PCBA. The second step is to use an electric soldering iron and solder to solder and fix the FET on the PCBA. The third step is to manually install the FET on the PCBA. Shell, the fourth step is to install the press buckle to make the field effect tube close to the shell to ensure good heat dissipation;

Method two (fixed manually, wave soldering): The first step is to fix the FET on the shell through a tooling fixture, the second step is to install the press button to make the FET close to the shell, and the third step is to match the PCBA to the field The effect tube pin is installed to the shell, and the fourth step adopts selective wave soldering.

The above-mentioned FET installation process cannot solve the following problems:

1. Since the field effect tube has the characteristics of large heat generation, the heat dissipation requirements are particularly high. If the field effect tube is welded to the PCBA first, in order to ensure heat dissipation, mechanical deformation must be used to force the welding pin to deform to ensure the field effect The tube is close to the shell, which is detrimental to the long-term durability of the product;

2. Since the FET is pressed tightly to the shell first by pressing the buckle, the PCBA board can only be manually installed in the hole, which will cause the pins to be uncovered, and the pins are dirty, which affects the connectivity and functionality of the FET. .

Therefore, how to design an installation method for field effect transistors with high operability and good quality of finished products is a technical problem to be solved urgently in the industry.

Summary of the invention

In order to solve the defects of poor welding effect of the existing field effect tube installation process and affecting the quality of the finished product, the present invention proposes a vehicle-mounted charger and a field effect tube installation method thereof.

The technical scheme adopted by the present invention is to design a field effect tube installation method for a vehicle-mounted charger. The housing of the vehicle-mounted charger is provided with an accommodation cavity and a coolant flow channel arranged in the accommodation cavity; the installation method of the field effect tube includes the following step:

Step 1. Mount several FETs on the bracket, and fix the bracket on the circuit board;

Step 2. Put the side of the circuit board fixed with the bracket facing down into the housing cavity of the shell, the bracket is located on one side of the coolant flow channel, and the field effect tube is located between the bracket and the coolant flow channel;

Step 3. Place the field effect tube against the side wall of the coolant flow channel;

Step 4. Soldering the pins of the field effect transistor on the circuit board.

Preferably, in step 1, before the field effect tube is installed on the bracket, the pins of the field effect tube are first cut to a preset length.

Preferably, the field effect tube in step 1 is pasted to the support through double-sided tape.

Preferably, one side of the field effect tube is provided with a recessed hole, the side of the recessed hole is covered with double-sided tape, and the bracket is provided with a positioning column matching the recessed hole. When the field effect tube is installed on the bracket, the positioning column is inserted into the recessed hole in.

Preferably, the bottom of the bracket is provided with fixing feet, and the bracket is fixed on the circuit board by welding the fixing feet.

Preferably, after the FETs are installed on the bracket in step 1, the pins of all FETs protrude from the bottom edge of the bracket; after the bottom of the bracket is fixed on the circuit board, all the pins of the FETs pass through Corresponding solder holes on the circuit board.

Preferably, the fixed legs of the bracket and the pins of the field effect tube are both soldered on the circuit board by selective wave soldering.

Preferably, in step 2, before the circuit board is loaded into the accommodating cavity of the housing, the following steps are performed first:

Load the circuit board into the positioning tray. The positioning tray is provided with at least one accommodating slot, and the side with the bracket fixed on the circuit board is placed in the accommodating slot; the housing and the positioning tray are placed in designated positions respectively, and the robot is used to grasp Take the circuit board in the accommodating groove into the accommodating cavity of the shell.

Preferably, in step 3, abutting the field effect tube on the side wall of the coolant flow channel includes the following steps: inserting the elastic sheet into the accommodating cavity from the through hole on the bottom surface of the housing, and the top end of the elastic sheet is inclined to the bracket to Push the field effect tube against the side wall of the coolant flow channel; lock and fix the bottom of the shrapnel on the shell.

The present invention also proposes a vehicle-mounted charger, which adopts the above-mentioned field effect tube installation method.

Compared with the prior art, the present invention first installs the field effect tube on the bracket, and then fixes the bracket to the circuit board. The bracket plays the role of positioning the field effect tube, and the circuit board is installed in the housing cavity of the housing. , Then use shrapnel and other components to push the bracket closer to the coolant flow channel, so that the field effect tube is attached to the side wall of the coolant flow channel, and finally the field effect tube and circuit board are welded, and the field effect tube is welded to the pins In a natural state, there are no problems of deformation and durability, and the production process is standardized and automated, which can save labor resources and improve production efficiency.

Description of the drawings

The present invention will be described in detail below in conjunction with embodiments and drawings, in which:

Figure 1 is a schematic diagram of the structure of the field effect tube and the bracket in the present invention;

Figure 2 is a schematic diagram of the structure of the positioning tray in the present invention.

detailed description

The field effect tube installation method proposed by the present invention is applicable to a vehicle-mounted charger. The housing of the vehicle-mounted charger is provided with an accommodating cavity and a cooling fluid channel arranged in the accommodating cavity, and the cooling fluid channel is located in the middle of the accommodating cavity The outer shape of the cooling liquid flow channel is U-shaped when viewed from the top of the casing, and the casing is provided with an inlet connected to one end of the cooling liquid flow channel and an outlet connected to the other end of the cooling liquid flow channel.

As shown in FIG. 1, the field effect tube 1 is installed on the bracket 2, and a positioning structure that cooperates with each other is designed between the field effect tube 1 and the bracket 2. In a preferred embodiment, one side of the lettering on the field effect tube 1 is provided with recessed holes, and the bracket 2 is provided with a row of spaced positioning posts, and each positioning post can be inserted and matched with the recessed holes, and a plurality of field effect tubes 1 Installed in a row on the bracket 2 in turn. After the FET 1 is installed on the bracket 2, all the pins 11 of the FET 1 protrude from the bottom edge of the bracket 2. After the bottom of the bracket 2 is fixed on the circuit board, all the pins 11 of the FET 1 are Passing through the corresponding welding holes on the circuit board, in order to realize the standardized installation of the field effect tube 1, the length of the pins 11 of the field effect tube 1 extending out of the welding holes of the circuit board is the same.

It should be noted that there are many ways for the field effect tube 1 to be mounted on the bracket 2, which can be selected according to actual needs. The present invention only uses one of them as an example. After aligning the concave hole with the positioning post, press the field effect tube 1 onto the bracket 2 to make the double-sided adhesive on the field effect tube 1 adhere to the bracket.

As shown in Figures 1 and 2, the bottom of the bracket 2 is provided with fixing feet, and the bracket 2 is fixed on the circuit board by welding the fixing feet. The circuit board is provided with mounting holes for inserting the fixing feet. The bracket 2 is fixed on the circuit board. The bracket 2 and the circuit board are assembled into the positioning tray 3 as a whole. The positioning tray 3 is provided with at least one accommodating groove 31. The actual number of the accommodating grooves 31 can be two or three or even more, which can be designed according to actual production needs. . Place the housing and the positioning tray 3 at the designated positions respectively, and use the robot to grab the circuit board in the receiving groove 31 and put it into the housing cavity of the housing, and place the side with the bracket on the circuit board facing down in the receiving groove 31 , The relatively flat side of the circuit board is facing up, which is convenient for the manipulator to grip the circuit board. After the manipulator grips the circuit board, it only needs to move up, down, and translate to load the circuit board into the housing cavity of the housing. There is no need for complicated flipping actions, and the automation cost is low.

After the circuit board is installed in the accommodating cavity, the bracket 2 is located on one side of the cooling liquid flow channel, and the field effect tube 1 is located between the bracket 2 and the cooling liquid flow channel. Place the cavity, the pin 11 of the field effect tube 1 extends upwards from the top surface of the circuit board, and the subsequent welding of the pin 11 of the field effect tube 1 and the circuit board can be directly operated on the top of the circuit board, which is simple, convenient and operability High, can achieve standardized mass production.

Insert the shrapnel into the accommodating cavity from the through hole on the bottom surface of the shell. The shrapnel is L-shaped, and the top of the shrapnel is inclined to the bracket 2. Use the shrapnel to push the bracket 2 closer to the coolant flow channel to make the field effect tube 1 abut the cooling fluid. On the side wall of the liquid flow channel, the bottom of the shrapnel is locked and fixed on the casing. The bottom surface of the casing is provided with a fixing groove adjacent to the through hole. The fixing groove communicates with the through hole to fit the shape of the shrapnel, and the bottom of the shrapnel passes The screw is locked in the fixing groove to prevent it from protruding from the bottom surface of the housing.

Specifically, the installation method of the field effect tube 1 includes the following steps:

Step 1. Mount a number of FETs 1 on the bracket 2, and fix the bracket 2 on the circuit board.

Step 1 includes the following processes:

Step 1.1: Cut the pin 11 of the FET 1 to a preset length;

Step 1.2. Paste double-sided tape on the lettering surface of the field effect tube 1;

Step 1.3. Manually install the field effect tube 1 to the bracket 2 in turn, align the concave hole of the lettering surface of the field effect tube 1 with the positioning column, and glue the field effect tube 1 and the bracket 2 with double-sided adhesive;

Step 1.4. Mount the bracket 2 with the FET 1 installed on the circuit board, and insert the fixing pins of the bracket 2 into the mounting holes on the circuit board;

Step 1.5: Solder and fix the fixing legs of the bracket 2 to the circuit board by selective wave soldering.

Step 2. Put the side of the circuit board fixed with the bracket 2 facing down into the housing cavity of the shell. The bracket 2 is located on one side of the cooling fluid channel, and the field effect tube 1 is located between the bracket 2 and the cooling fluid channel. between.

Step 2 includes the following processes:

Step 2.1. Place the side of the circuit board on which the bracket 2 is fixed face down into the positioning slot of the positioning tray 3;

Step 2.2. Put the positioning tray 3 with the circuit board on the feeding mechanism of the machine;

Step 2.3: The manipulator of the machine automatically clamps the circuit board in the positioning tray 3 from the feeding mechanism, and puts it into the shell that has been transported to the designated processing position according to the preset coordinate track.

Step 3. Place the field effect tube 1 against the side wall of the coolant flow channel.

Step 3 includes the following processes:

Step 3.1. Insert the shrapnel from the through hole on the bottom surface of the housing into the accommodating cavity by manipulator or manually;

Step 3.2. Tighten the connecting screw between the bottom of the shrapnel and the fixing slot with an automatic screw gun or a manual screw gun. The torque of the screw gun can be set according to actual needs, for example, select a torque value in the range of 3.2Nm to 3.5Nm.

Step 4. Solder the pin 11 of the field effect tube 1 on the circuit board by selective wave soldering.

The above descriptions are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection of the present invention. Within range.

Claims

A method for installing a field effect tube of a vehicle-mounted charger, wherein the housing of the vehicle-mounted charger is provided with an accommodating cavity and a coolant flow channel provided in the accommodating cavity; characterized in that, the method for installing the field-effect tube includes The following steps:

Step 1. Mount several field effect tubes on the bracket, and fix the bracket on the circuit board;

Step 2. Put the side of the circuit board on which the bracket is fixed face down into the accommodating cavity of the casing, the bracket is located on one side of the coolant flow channel, and the field effect tube Located between the bracket and the cooling liquid flow channel;

Step 3. Place the field effect tube against the side wall of the coolant flow channel;

Step 4. Soldering the pins of the field effect transistor on the circuit board.
The field effect tube installation method of claim 1, wherein in step 1, before the field effect tube is installed on the bracket, the pins of the field effect tube are first cut to a preset length .
5. The method for installing a field effect tube according to claim 1, wherein the field effect tube in step 1 is pasted to the bracket by double-sided adhesive.
The field effect tube installation method according to claim 3, wherein a concave hole is provided on one side of the field effect tube, the double-sided tape is attached to the side where the concave hole is located, and the bracket is provided with The positioning post is matched with the concave hole, and when the field effect tube is installed on the bracket, the positioning post is inserted into the concave hole.
5. The field effect tube mounting method according to claim 1, wherein the bottom of the bracket is provided with fixing feet, and the bracket is fixed on the circuit board by welding the fixing feet.
The field effect tube installation method of claim 1, wherein after the field effect tube is installed on the bracket in the step 1, all the pins of the field effect tube protrude from the bracket. Bottom edge; after the bottom of the bracket is fixed on the circuit board, all the pins of the field effect tube pass through the corresponding welding holes on the circuit board.
7. The field effect tube mounting method according to claim 5 or 6, characterized in that the fixed legs of the bracket and the pins of the field effect tube are both soldered on the circuit board by selective wave soldering.
4. The method for mounting a field effect tube according to claim 1, wherein in step 2, before the circuit board is installed in the accommodating cavity of the housing, the following steps are first performed:

Loading the circuit board into a positioning tray, the positioning tray is provided with at least one accommodating groove, and the circuit board is placed in the accommodating groove with the side fixed with the bracket facing down;

The casing and the positioning tray are respectively placed at designated positions, and the circuit board in the containing groove is grabbed by a manipulator and loaded into the containing cavity of the casing.
The field effect tube installation method according to claim 1, wherein in the step 3, abutting the field effect tube on the side wall of the cooling liquid flow channel comprises the following steps:

Insert an elastic piece into the accommodating cavity from the through hole on the bottom surface of the casing, and the top end of the elastic piece is inclined to the bracket to push the field effect tube to abut against the side of the coolant flow channel On the wall

The bottom of the elastic sheet is locked and fixed on the shell.
The vehicle-mounted charger is characterized in that the vehicle-mounted charger adopts the field effect tube installation method according to any one of claims 1 to 9.