Welding positioning tool for DBC assembly

Abstract

The invention discloses a DBC assembly welding and positioning tool, and relates to the technical field of DBC substrate welding, the DBC assembly welding and positioning tool comprises a bottom plate, a positioning frame and a DBC substrate, the periphery of the surface of the bottom plate is provided with hole sites, the positioning frame is placed on the surface of the bottom plate in an attached mode, pins are fixed to the periphery of the bottom of the positioning frame, the surface of the positioning frame is provided with holes, and the holes are communicated with the holes. A positioning edge is arranged on the inner side face of the open hole, and a DBC substrate is placed in the open hole. According to the DBC assembly welding positioning tool, the positioning frame capable of being assembled with the bottom plate in a matched mode is attached to the bottom plate, so that the position of the hole in the surface of the positioning frame coincides with the to-be-welded area on the surface of the bottom plate, and therefore a DBC substrate placed in the hole is accurately positioned, the DBC substrate can be accurately installed at the designated position of the surface of the bottom plate in a matched mode, and the welding efficiency is improved. Therefore, dislocation and deviation are prevented, and the welding effect is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of DBC substrate welding, in particular to a DBC assembly welding positioning tool. BACKGROUND

[0002] When the DBC substrate is assembled, tin paste needs to be coated on the back surface (bottom surface) of the DBC substrate, and the DBC substrate needs to be accurately placed on the designated position of the bottom plate for adaptive installation, and then the whole is sent into a formic acid furnace to be welded along with the debugged temperature-time curve.

[0003] When the existing DBC substrate is placed on the surface of the bottom plate for adaptive installation, the surface of the bottom plate cannot be provided with a positioning indication area or a positioning structure, so that it is difficult for manual operation to accurately place the DBC substrate on the designated position for adaptive installation, which can easily cause the DBC substrate to be offset from the bottom plate, thereby affecting the welding effect. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a DBC assembly welding positioning tool, which solves the problems raised in the background art.

[0005] To achieve the above purpose, the present application realizes the following technical scheme: a DBC assembly welding positioning tool, comprising a bottom plate, a positioning frame and a DBC substrate, a plurality of hole positions are formed around the surface of the bottom plate, and the positioning frame is placed on the surface of the bottom plate, a plurality of pins are fixed around the bottom of the positioning frame, a plurality of openings are formed on the surface of the positioning frame, a positioning edge is arranged on the inner side of the opening, and the DBC substrate is placed in the opening.

[0006] Further, the number of pins is one-to-one with the number of hole positions.

[0007] Further, the pins are inserted into the inside of the hole positions.

[0008] Further, the bottom end of the pin is in a round head shape.

[0009] Further, the outer opening size of the pin is matched with the inner opening size of the hole position.

[0010] Further, the opening is provided with two openings.

[0011] Further, the opening position is coincided with the surface of the bottom plate to be welded.

[0012] Further, the bottom surface of the DBC substrate is matched with the surface of the bottom plate in the opening.

[0013] Further, the side surface of the DBC substrate is matched with the positioning edge of the inner side of the opening.

[0014] The application provides a DBC assembly welding positioning tool, which has the following beneficial effects: 1. The DBC assembly welding positioning tool is provided with a positioning frame which can be assembled with the bottom plate, and the positioning frame is attached to the bottom plate, so that the opening position on the surface of the positioning frame coincides with the area to be welded on the surface of the bottom plate, thereby accurately positioning the DBC substrate placed in the opening, so that the DBC substrate can be accurately installed on the specified position on the surface of the bottom plate, thereby preventing misalignment and offset, and ensuring the welding effect.

[0015] 2. The DBC assembly welding positioning tool, when the positioning frame is pressed by hand to attach to the surface of the bottom plate and the pin is inserted into the hole position, the elastic ball is elastically deformed to make the locking claws abut against the inner wall of the hole position, so as to enhance the firmness of the assembled positioning frame and bottom plate, thereby avoiding slight misalignment and offset caused by loosening, and when the temperature is increased to the upper limit of 245 DEG C in the final welding period, the memory metal is completely expanded by heating, and during the expansion process, the outer transmission plate is first pushed to make the locking claws close to each other to reduce the outer diameter size, and then the separation ring plate is pushed to extend, so that the positioning frame and the bottom plate are separated, and the pin is separated from the hole position, so that the positioning frame can be easily removed when the welding is completed and the whole is cooled to room temperature, thereby solving the problem that the positioning frame is difficult to disassemble due to the over-tightening of the pin inserted into the hole position. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a schematic structural view of the assembled bottom plate and positioning frame of the DBC assembly welding positioning tool of the application; Figure 2 It is a schematic structural view of the welded DBC substrate and hole position of the DBC assembly welding positioning tool of the application; Figure 3 It is a schematic structural view of the sectional structure of the positioning frame of the DBC assembly welding positioning tool of the application; Figure 4 It is a schematic structural view of the Figure 3 enlarged structure at A of the DBC assembly welding positioning tool of the application; Figure 5 It is a schematic structural view of the Figure 3 enlarged structure at B of the DBC assembly welding positioning tool of the application; Figure 6 It is a schematic structural view of the elastic ball of the DBC assembly welding positioning tool of the application.

[0017] In the figure: 1, bottom plate; 2, hole position; 3, positioning frame; 4, pin; 5, opening; 6, positioning edge; 7, DBC substrate; 8, elastic ball; 9, locking claw; 10, inner transmission plate; 11, outer transmission plate; 12, metal chamber; 13, transition space; 14, plate groove; 15, memory metal; 16, separation ring plate; 17, anti-disengagement ring plate. DETAILED DESCRIPTION

[0018] The embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0019] As shown in Figures 1-2 The present application provides a technical solution: a DBC assembly welding positioning tool, comprising a bottom plate 1, a positioning frame 3 and a DBC substrate 7, a hole position 2 is formed around the surface of the bottom plate 1, and the positioning frame 3 is placed on the surface of the bottom plate 1, a pin 4 is fixed around the bottom of the positioning frame 3, and an opening 5 is formed on the surface of the positioning frame 3, a positioning edge 6 is arranged on the inner side of the opening 5, and the DBC substrate 7 is placed inside the opening 5, the number of the pins 4 is one-to-one with the number of the hole positions 2, the pins 4 are inserted into the hole positions 2, the bottom end of the pin 4 is round, the outer opening size of the pin 4 is matched with the inner opening size of the hole position 2, there are two openings 5 in total, the position of the opening 5 coincides with the surface of the bottom plate 1 to be welded, the bottom surface of the DBC substrate 7 is attached to the surface of the bottom plate 1 inside the opening 5, and the side surface of the DBC substrate 7 is attached to the positioning edge 6 on the inner side of the opening 5; The specific operation is as follows: the positioning frame 3 is placed on the surface of the bottom plate 1 so that the pins 4 are inserted into the respective corresponding hole positions 2, at this time the position of the opening 5 on the surface of the positioning frame 3 coincides with the surface of the bottom plate 1 to be welded, then tin paste is applied to the bottom surface of the DBC substrate 7 and placed inside the opening 5, so that the bottom surface of the DBC substrate 7 is attached to the surface of the bottom plate 1, at this time the positioning edge 6 is attached to the four side edges of the DBC substrate 7, thereby accurately positioning the DBC substrate 7 to the specified position on the surface of the bottom plate 1 to complete the matching installation, and then the whole is sent into a formic acid furnace for welding according to the debugged temperature-time curve; Based on the above description, the positioning frame 3 which can be matched with the bottom plate 1 is attached, so that the position of the opening 5 on the surface of the positioning frame 3 coincides with the surface of the bottom plate 1 to be welded, thereby accurately positioning the DBC substrate 7 placed inside the opening 5, so that the DBC substrate 7 can be accurately matched and installed with the specified part of the surface of the bottom plate 1, thereby preventing misalignment and offset, and ensuring the welding effect; As shown in Figures 1-6 The pin 4 is internally provided with an elastic ball 8, and the outer side surface of the pin 4 is annularly embedded and slidingly connected with a lock catch 9, the inner side surface bottom of the lock catch 9 is connected with an inner transmission plate 10, and the inner transmission plate 10 penetrates into the inside while being attached to the surface of the elastic ball 8, and the outer side surface bottom of the lock catch 9 is connected with an outer transmission plate 11; Specific operation as follows, in the use of the pin 4 into the hole 2 inside the insertion of the downward pressure force, due to the end of the lock claw 9 is inclined to set it can smoothly into the hole 2 inside, at this time the hole 2 to the lock claw 9 inside force makes the inner transmission plate 10 extrusion elastic ball 8 makes it compression deformation, and through the elastic force of elastic ball 8 makes the lock claw 9 outside face to the hole 2 inside face, to enhance the pin 4 after insertion into the hole 2 connection firmness, to avoid the two due to loose and lead to the opening 5 position and the surface of the bottom plate 1 to be welded area slight deviation, wherein the elastic ball 8 is heat resistant rubber material can keep elastic in high temperature environment; As Figures 1-6 The bottom surface of the positioning frame 3 is provided with a metal chamber 12, a transition space 13 and a plate groove 14 from inside to outside outside the pin 4, and the inside of the metal chamber 12 is provided with a memory metal 15, the memory metal 15 is located at the same height with the outer transmission plate 11, the inside of the transition space 13 is provided with an anti-loose ring plate 17, and the end of the anti-loose ring plate 17 is connected with a separation ring plate 16, the anti-loose ring plate 17 and the separation ring plate 16 are sleeved and slidably connected on the outer wall of the pin 4, and the separation ring plate 16 is located inside the plate groove 14, and the surface of the separation ring plate 16 is flush with the bottom surface of the positioning frame 3; Specific operation as follows, after the positioning frame 3 and the bottom plate 1 are assembled, the separation ring plate 16 is located inside the plate groove 14, and the bottom surface of the separation ring plate 16 is attached to the surface of the bottom plate 1, while the anti-loose ring plate 17 is lifted to the highest position of the transition space 13, and the memory metal 15 is made of nickel titanium alloy, and the shape of the memory metal 15 in normal temperature state is circular and only occupies one third of the area of the metal chamber 12; The phase transition temperature Af of nickel titanium alloy is mainly controlled by the atomic proportion of nickel Ni and titanium Ti and trace alloying elements such as Cu, Cr and Fe, for example, the Af temperature of the basic nickel titanium alloy (Ni content 50%-51% atomic ratio) is usually low, such as-50℃ to 100℃, but by reducing the nickel content such as Ni≤50% or adding high temperature stable elements such as Cr, V, the Af temperature can be significantly improved, for example, adding 3%-5% copper Cu can widen the phase transition temperature range and improve the thermal stability, and after adjusting the composition, the Af temperature can be increased to more than 200℃, so that the phase transition temperature Af of the memory metal 15 is adjusted to 245℃ by adjusting the composition, and the memory metal 15 deforms and expands when it reaches 245℃; Wherein 245℃ is the upper limit of the temperature-time curve when the DBC substrate 7 is welded with the bottom plate 1, and the formic acid furnace is used to weld the assembled DBC substrate 7 and the bottom plate 1, the formic acid reduction pretreatment stage is 150-200℃, at this time the formic acid gas and the metal oxide such as the DBC copper-clad layer and the oxide layer of the bottom plate 1 have a chemical reaction to remove the surface oxide film, this stage needs to be maintained for 60-120 seconds to ensure that the formic acid is fully infiltrated, and then the temperature is raised to above the melting point of the solder paste, that is, between 230-245℃, and the formic acid furnace is 240℃ at this time, this stage completes the melting of the solder paste to make the DBC substrate 7 and the bottom plate 1 metallurgical bonding; When the temperature inside the formic acid furnace rises to 240℃, the memory metal 15 is in a mixed state of martensite and austenite, that is, partially expanded, and at this time the remaining space of the metal chamber 12 is used to accommodate the expanded part of the memory metal 15, and then the temperature is raised to 245℃ (where the heat loss is ignored) just before the welding is completed, which is the upper limit of the welding of the DBC substrate 7 and the bottom plate 1, which ensures the welding quality of the DBC substrate 7 and the bottom plate 1 while making the memory metal 15 deform completely, at this time the memory metal 15 expands completely to push the outer transmission plate 11 first to make the locking claw 9 slide and shrink into the inside of the pin 4, and then push the anti-disengagement ring plate 17 down with the expansion of the memory metal 15 to make it carry the disengagement ring plate 16 to slide down along the outer wall of the pin 4 Figure 4 、 Figure 5 For the structure display of the positioning frame 3 after turning over, as shown, the disengagement ring plate 16 slides up along the outer wall of the pin 4), so as to extend from the inside of the plate groove 14, at this time the extension of the disengagement ring plate 16 makes the positioning frame 3 separate from the bottom plate 1, and the pin 4 disengages from the hole position 2, and then after cooling to room temperature, the memory metal 15 returns to the initial state, at this time there is no external pressure, and the outer diameter of the locking claw 9 is larger than the inner diameter of the hole position 2 so that it cannot be inserted into the inside, so that when the whole is taken out from the formic acid furnace and cooled to room temperature, the positioning frame 3 can be easily removed; Based on the above description, when the positioning frame 3 is pressed by hand to fit the surface of the bottom plate 1 and the pin 4 is inserted into the inside of the hole position 2, the locking claw 9 is pressed against the inner wall of the hole position 2 by the elastic action of the elastic ball 8 to enhance the firmness of the assembled positioning frame 3 and the bottom plate 1 to avoid slight misalignment and offset, and when the temperature is raised to the upper limit of 245℃ at the final stage of welding, the memory metal 15 is completely expanded by heat, and in the expansion process, it first pushes the outer transmission plate 11 to make the locking claw 9 approach each other to reduce the outer diameter, and then pushes the disengagement ring plate 16 to extend, so that the positioning frame 3 is separated from the bottom plate 1, and the pin 4 disengages from the hole position 2, so that when the whole is welded and taken out and cooled to room temperature, the positioning frame 3 can be easily removed, solving the problem that the pin 4 is too tight when inserted into the inside of the hole position 2, causing the positioning frame 3 to be difficult to disassemble.

[0020] In summary, the DBC assembly welding positioning tool, in use, first places the positioning frame 3 on the surface of the base plate 1 so that the pins 4 are inserted into the respective corresponding hole positions 2, wherein the end of the locking claw 9 is inclined to facilitate the insertion into the hole position 2, at this time the hole position 2 exerts an inward force on the locking claw 9 to make the inner transmission plate 10 extrude the elastic ball 8 to make it compress and deform, and the elastic force of the elastic ball 8 makes the outer side of the locking claw 9 adhere to the inner side of the hole position 2, to enhance the connection firmness after the pin 4 is inserted into the hole position 2, to avoid the slight deviation of the opening 5 position from the surface of the base plate 1 to be welded due to loosening; The opening 5 position on the surface of the positioning frame 3 coincides with the surface of the base plate 1 to be welded, and then the DBC substrate 7 is coated with tin paste and placed in the opening 5, so that the bottom surface of the DBC substrate 7 adheres to the surface of the base plate 1, at this time the positioning edge 6 adheres to the four side edges of the DBC substrate 7, thereby accurately positioning the DBC substrate 7 to the specified position on the surface of the base plate 1 to complete the adaptive installation, and then the whole is sent into the formic acid furnace for welding according to the debugged temperature-time curve; When the DBC substrate 7 and the base plate 1 after assembly are welded by the formic acid furnace, the formic acid reduction pretreatment stage is 180℃, at this time the formic acid gas reacts with the metal oxide such as the DBC copper clad layer and the oxide layer of the base plate 1 to remove the surface oxide film, this stage needs to be maintained for 90 seconds to ensure that the formic acid is fully soaked, and then the temperature is raised above the melting point of the tin paste, here the formic acid furnace is taken as 240℃, this stage completes the melting of the tin paste, so that the DBC substrate 7 and the base plate 1 are metallurgically combined; When the temperature inside the formic acid furnace rises to 240℃, the memory metal 15 is in a mixed state of martensite and austenite, that is, partially expanded, at this time the remaining space of the metal chamber 12 accommodates the expanded part of the memory metal 15, and then the temperature is raised to 245℃, which is the upper limit of the welding of the DBC substrate 7 and the base plate 1, to ensure the welding quality of the DBC substrate 7 and the base plate 1 while making the memory metal 15 deform completely, at this time the completely expanded memory metal 15 first pushes the outer transmission plate 11 to make the locking claw 9 slide and retract into the pin 4, and then pushes down the anti-disengagement ring plate 17 with the expansion of the memory metal 15 to make it carry the separation ring plate 16 to slide down along the outer wall of the pin 4, so as to stretch out from the plate groove 14, at this time the stretching out of the separation ring plate 16 makes the positioning frame 3 separate from the base plate 1, and the pin 4 separates from the hole position 2, and then after cooling to room temperature, the memory metal 15 returns to the initial state, at this time there is no external pressure, and the outer diameter of the locking claw 9 is larger than the inner diameter of the hole position 2 and cannot be inserted into it again, so that when the whole is taken out from the formic acid furnace and cooled to room temperature, the positioning frame 3 can be easily removed.

[0021] The embodiments of the present application are presented by way of example and description, and are not intended to be exhaustive or to limit the application to the form disclosed. Many modifications and variations will be apparent to those skilled in the art. Embodiments are chosen and described in order to best explain the principles of the application and its practical application, and to thereby enable others skilled in the art to best utilize the application in various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

1. A welding and positioning fixture for DBC components, comprising a base plate (1), a positioning frame (3), and a DBC substrate (7), characterized in that: The base plate (1) has holes (2) around its surface, and a positioning frame (3) is placed on the surface of the base plate (1). Pins (4) are fixed around the bottom of the positioning frame (3), and the surface of the positioning frame (3) has openings (5). A positioning edge (6) is provided on the inner side of the opening (5), and a DBC substrate (7) is placed inside the opening (5). An elastic ball (8) is provided inside the pin (4), and a locking claw (9) is inserted and slidably connected to the outer side of the pin (4) in a ring shape. The inner side of the locking claw (9) The bottom is connected to an inner transmission plate (10), and the bottom of the outer side of the locking claw (9) is connected to an outer transmission plate (11). The bottom surface of the positioning frame (3) is provided with a metal chamber (12), a transition space (13) and a plate groove (14) from the inside to the outside of the pin (4). The metal chamber (12) is provided with memory metal (15). The transition space (13) is provided with an anti-detachment ring plate (17). The end of the anti-detachment ring plate (17) is connected to a separation ring plate (16), and the separation ring plate (16) is located inside the plate groove (14).

2. The DBC component welding positioning fixture according to claim 1, characterized in that: The number of pins (4) is set one-to-one with the number of holes (2).

3. The DBC component welding positioning fixture according to claim 1, characterized in that: The pin (4) is inserted into the hole (2).

4. The DBC component welding positioning fixture according to claim 1, characterized in that: The bottom end of the pin (4) is rounded.

5. The DBC component welding positioning fixture according to claim 1, characterized in that: The outer opening size of the pin (4) is adapted to the inner opening size of the hole (2).

6. The DBC component welding positioning fixture according to claim 1, characterized in that: There are two openings (5), and the position of the openings (5) coincides with the welding area on the surface of the base plate (1).

7. The DBC component welding positioning fixture according to claim 1, characterized in that: The bottom surface of the DBC substrate (7) is in contact with the surface of the base plate (1) inside the opening (5), and the side surface of the DBC substrate (7) is in contact with the positioning edge (6) of the inner side surface of the opening (5).

8. The DBC component welding positioning fixture according to claim 1, characterized in that: The inner transmission plate (10) penetrates into the inside of the pin (4) and is attached to the surface of the elastic ball (8), while the anti-detachment ring plate (17) and the separation ring plate (16) are sleeved and slidably connected to the outer wall of the pin (4).

9. The DBC component welding positioning fixture according to claim 1, characterized in that: The shape memory metal (15) and the outer transmission plate (11) are at the same height, and the surface of the separation ring plate (16) is flush with the bottom surface of the positioning frame (3).

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