A SMT positioning fixture

Abstract

The present invention discloses an SMT positioning fixture, which relates to the field of surface mounting technology, including a tray, a placement slot is provided on the top of the tray, lateral pushing mechanisms are provided at both ends of the inner side of the placement slot, a driving mechanism is provided on the front side of the top of the tray, a bottom shell is fixedly provided on the bottom of the tray, a lifting mechanism is provided in the middle of the inner side of the bottom shell, limiting mechanisms are provided on both sides of the lifting mechanism, a plurality of adjustable positioning mechanisms are provided on the top of the lifting mechanism, and a trigger mechanism is provided inside the plurality of adjustable positioning mechanisms; the driving gear in the driving mechanism drives the driven gear in the lifting mechanism to rotate, and the lifting plate in the lifting mechanism drives the second screw in the limiting mechanism to rotate through the limiting plate in the limiting mechanism. The present invention reduces the difficulty of positioning while ensuring the positioning accuracy, and has higher positioning strength, and will not cause the motherboard to deviate during the positioning process.

Description

Technical Field

[0001] The present invention relates to the field of surface mounting technology, and in particular to a SMT positioning fixture. Background Art

[0002] The main board and sub-board of the mobile phone are soldered through SMT, and the steps include: first tinning the main board, then mounting the sub-board on the main board, and finally passing the main board and the sub-board through the reflow furnace. In order to avoid the main board and the sub-board being offset during the furnace and causing a tin short circuit, a positioning fixture is needed to position the main board and the sub-board.

[0003] The invention patent with authorization announcement number CN 110385500 B discloses an SMT positioning fixture, which includes a tray, a positioning assembly, a first upper magnet, a second upper magnet and a lower magnet. The tray is for placing a mobile phone motherboard, and a positioning hole is opened on the tray. The positioning assembly includes a substrate, a slider group and a positioning column. The slider group is slidably arranged on the substrate, the positioning column is arranged on the substrate and located in the positioning hole of the tray, the first upper magnet and the second upper magnet are fixed on the tray, and the lower magnet is fixed on the slider group.

[0004] When the above-mentioned fixture is used to position the mainboard, the mainboard needs to be placed in the receiving groove on the top of the tray first, and then the positioning column needs to be moved upward and passed through the mainboard by pushing the operating block to achieve positioning.

[0005] In order to ensure the positioning accuracy, the specifications of the positioning column need to be effectively matched with the positioning holes on the mainboard. In this case, when the positioning column is too thick, when the positioning column enters the positioning hole on the mainboard, it is easy for the mainboard to be lifted up due to the placement error of the mainboard, increasing the difficulty of positioning implementation. When the positioning column is too thin, the positioning column cannot play a good positioning role after entering the positioning hole on the mainboard, affecting the quality of subsequent finished products.

[0006] At the same time, when the magnetic adsorption method is used to realize the rising of the positioning column, when the lower magnet moves to the corresponding position of the second upper magnet, the fixed plate will drive the positioning column to rise while also driving the substrate to rise synchronously, and the rising process is relatively rapid due to the magnetic adsorption. In this way, the substrate will impact the tray after rising. After the impact force acts on the main board, it is easy to cause the main board to shift, which will further affect the subsequent penetration of the positioning column.

[0007] Therefore, it is necessary to invent a SMT positioning fixture to solve the above problems. Summary of the invention

[0008] The object of the present invention is to provide a SMT positioning fixture to solve the problems raised in the above background technology.

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an SMT positioning fixture, comprising a tray, a placement groove is provided on the top of the tray, lateral pushing mechanisms are provided at both ends of the inner side of the placement groove, a driving mechanism is provided on the front side of the top of the tray, a bottom shell is fixedly provided on the bottom of the tray, a lifting mechanism is provided in the middle of the inner side of the bottom shell, limiting mechanisms are provided on both sides of the lifting mechanism, a plurality of adjustable positioning mechanisms are provided on the top of the lifting mechanism, and a trigger mechanism is provided inside the plurality of adjustable positioning mechanisms;

[0010] The driving gear in the driving mechanism drives the driven gear in the lifting mechanism to rotate, the lifting plate in the lifting mechanism drives the second screw in the limiting mechanism to rotate through the limiting plate in the limiting mechanism, the eccentric wheel in the limiting mechanism pushes the pushing bar in the lateral pushing mechanism, and the trigger block in the trigger mechanism pushes the pushing block in the adjustable positioning mechanism;

[0011] The adjustable positioning mechanism includes an avoidance hole, a hollow positioning column, two sets of positioning components and a slide slot, and the positioning component includes a positioning push rod, a push block, a connecting sleeve plate, a sliding rod and a second spring;

[0012] The avoidance hole is opened at the bottom of the tray and communicates with the placement groove, the hollow positioning column is fixedly arranged on the top of the lifting plate and extends to the inner side of the avoidance hole, the positioning push rod is slidably nested and arranged on the top of the side of the hollow positioning column, the push block is fixedly arranged on the inner side of the positioning push rod, the connecting sleeve is fixedly sleeved and arranged on the outer side of the push block, the sliding rod is fixedly arranged on the outer side of the connecting sleeve, and is slidably nested on the inner wall of the hollow positioning column, the second spring is sleeved and arranged on the outer side of the sliding rod, one end of the second spring is fixedly connected to the connecting sleeve and the other end is fixedly connected to the inner wall of the hollow positioning column, two slide grooves are provided, and the two slide grooves are respectively opened at the bottom of both sides of the hollow positioning column;

[0013] The trigger mechanism comprises a fixed rod, a telescopic rod, a fixed collar, a third spring and a trigger block;

[0014] The fixed rod is slidably arranged on the inner sides of the two sliding grooves, and both ends thereof are fixedly connected to the inner walls of the avoidance hole, the telescopic rod is fixedly arranged on the top of the fixed rod, the fixed sleeve is fixedly sleeved on the outer side of the inner shaft of the telescopic rod, the third spring is sleeved on the outer side of the telescopic rod, one end of the third spring is fixedly connected to the fixed rod and the other end is fixedly connected to the fixed sleeve, the trigger block is fixedly connected to the top end of the inner shaft of the telescopic rod, and the trigger block is fitted with the push block.

[0015] Preferably, the lateral pushing mechanism comprises a receiving groove, a slider, a first spring and a pushing bar;

[0016] The receiving groove is opened on the inner wall of the placement groove, the slider is slidably arranged on the inner side of the receiving groove, the first spring is fixedly connected to the inner side of the slider, the end of the first spring away from the slider is fixedly connected to the inner wall of the receiving groove, the pushing bar is fixedly arranged on the top of the slider, and the pushing bar is slidably arranged on the inner side of the placement groove.

[0017] Preferably, the driving mechanism comprises a driving shaft, a driving gear, a knob and a cross rib;

[0018] The driving shaft passes through the tray and extends to the bottom of the tray, and is rotatably connected to the tray through a bearing. The driving gear is fixedly sleeved on the outer bottom of the driving shaft, the knob is fixedly set on the top of the driving shaft, and the cross rib is fixedly set on the top of the knob.

[0019] Preferably, the lifting mechanism comprises a first screw rod, a driven gear and a lifting plate;

[0020] The first screw is rotatably nested in the center of the inner side of the bottom shell through a bearing, the driven gear is fixedly sleeved at the bottom of the outer side of the first screw and meshes with the driving gear, and the lifting plate is sleeved on the outer side of the first screw and threadedly connected to the first screw.

[0021] Preferably, the limiting mechanism comprises a limiting plate, a second screw and an eccentric wheel;

[0022] The limit plate is fixedly arranged on the side of the lifting plate, the second screw rod passes through the limit plate and is threadedly connected with the limit plate, and the bottom end of the second screw rod is rotatably nested on the inner wall of the bottom shell through a bearing, and the eccentric wheel is fixedly arranged on the top end of the second screw rod, and the eccentric wheel is in contact with the adjacent pushing strip.

[0023] The present invention also provides a positioning method for an SMT positioning fixture, which specifically comprises the following steps:

[0024] S1, placing the main board inside the placement slot, and tinning the main board, then rotating the knob, so that the knob drives the driving gear to rotate through the driving shaft, and when the driving gear rotates, the first screw is driven through the driven gear, so that the first screw drives the lifting plate to rise;

[0025] S2, when the lifting plate rises, it drives the limit plate to rise synchronously, and when the limit plate rises, it drives the second screw to rotate, thereby causing the eccentric wheel to rotate synchronously. When the eccentric wheel rotates, the eccentric wheel pushes the push bar, and then the two push bars pre-position the main board from both sides;

[0026] S3. When the lifting plate rises, it simultaneously drives multiple hollow positioning columns to rise. When the hollow positioning columns rise, their top ends gradually enter the positioning holes on the main board. During the continuous rise of the hollow positioning columns, the push blocks slide upward along the side walls of the trigger blocks. Then, under the push of the trigger blocks, the sliding rods are compressed by the connecting sleeves, driving the positioning push rods to slide outwards.

[0027] S4. When the rising distance of the hollow positioning column reaches the first threshold, the positioning push rod fits with the inner wall of the positioning hole on the main board. At this time, the knob is stopped from rotating, and the mobile phone sub-board is mounted on the top of the tinned main board. The hollow positioning column and the two positioning push rods synchronously pass through the positioning hole on the sub-board, thereby positioning the sub-board.

[0028] S5. Rotate the knob again to make the hollow positioning column continue to rise. When the rising distance of the hollow positioning column reaches the second threshold, the two positioning push rods can effectively position the main board and the sub-board from both sides of the positioning hole. Then, the main board and the sub-board are driven through the furnace by the device. After the furnace is passed, the knob is reversely rotated to synchronously reset the lateral pushing mechanism, the lifting mechanism, the limit mechanism and the multiple adjustable positioning mechanisms. Finally, the welded main board and the sub-board can be taken out from the inside of the placement slot.

[0029] Technical effects and advantages of the present invention:

[0030] The present invention is provided with a lateral pushing mechanism, a lifting mechanism, a limiting mechanism, an adjustable positioning mechanism and a triggering mechanism, so that when the lifting mechanism is driven, the lifting mechanism can drive the lateral pushing mechanism through the limiting mechanism while lifting the adjustable positioning mechanism, thereby enabling the lateral pushing mechanism to pre-position the mainboard. In actual production, the width of the placement slot can be made larger than the width of the mainboard, thereby making it more convenient to put in and take out the mainboard. In addition, during the process of the adjustable positioning mechanism being lifted, the triggering mechanism can trigger the adjustable positioning mechanism, thereby enabling the adjustable positioning mechanism to gradually position the mainboard. In addition, after the sub-board is mounted, the lifting mechanism can be used to drive the adjustable positioning mechanism again, thereby enabling the adjustable positioning mechanism to enhance the positioning effect on the mainboard and the sub-board, so that the mainboard and the sub-board cannot move horizontally and cannot shake in the vertical direction. Compared with the same type of devices in the prior art, the present invention reduces the positioning difficulty while ensuring the positioning accuracy, and has higher positioning strength. In addition, the mainboard will not be offset during the positioning process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall top view structure of the present invention.

[0032] Figure 2 It is a schematic diagram of the overall front cross-sectional structure of the present invention.

[0033] Figure 3 It is a schematic diagram of the front cross-sectional structure of the avoidance hole of the present invention.

[0034] Figure 4 It is a front cross-sectional structural schematic diagram of the adjustable positioning mechanism and the trigger mechanism of the present invention.

[0035] Figure 5 It is a front cross-sectional structural schematic diagram of the lateral pushing mechanism of the present invention.

[0036] Figure 6 It is a front view structural schematic diagram of the driving mechanism of the present invention.

[0037] In the figure: 1. tray; 2. placement slot; 3. lateral pushing mechanism; 31. accommodating slot; 32. slider; 33. first spring; 34. pushing strip; 4. driving mechanism; 41. driving shaft; 42. driving gear; 43. knob; 44. cross convex strip; 5. bottom shell; 6. lifting mechanism; 61. first screw rod; 62. driven gear; 63. lifting plate; 7. limiting mechanism; 71. limiting plate; 72. second screw rod; 73. eccentric wheel; 8. adjustable positioning mechanism; 81. avoidance hole; 82. hollow positioning column; 83. positioning push rod; 84. push block; 85. connecting sleeve; 86. sliding rod; 87. second spring; 88. slide slot; 9. trigger mechanism; 91. fixing rod; 92. telescopic rod; 93. fixing collar; 94. third spring; 95. trigger block. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1

[0040] The present invention provides Figure 1-6 An SMT positioning fixture shown includes a tray 1, a placement groove 2 is provided on the top of the tray 1, and the width of the placement groove 2 is greater than the width of the motherboard, so as to reduce the difficulty of placing the motherboard into the placement groove 2, and lateral pushing mechanisms 3 are provided at both ends of the inner side of the placement groove 2, and a driving mechanism 4 is provided at the front side of the top of the tray 1, and a bottom shell 5 is fixedly provided at the bottom of the tray 1, and a lifting mechanism 6 is provided at the middle of the inner side of the bottom shell 5, and limiting mechanisms 7 are provided on both sides of the lifting mechanism 6, and a plurality of adjustable positioning mechanisms 8 are provided on the top of the lifting mechanism 6, and a trigger mechanism 9 is provided inside the plurality of adjustable positioning mechanisms 8;

[0041] The driving gear 42 in the driving mechanism 4 drives the driven gear 62 in the lifting mechanism 6 to rotate, the lifting plate 63 in the lifting mechanism 6 drives the second screw 72 in the limiting mechanism 7 to rotate through the limiting plate 71 in the limiting mechanism 7, the eccentric wheel 73 in the limiting mechanism 7 pushes the pushing bar 34 in the lateral pushing mechanism 3, and the trigger block 95 in the trigger mechanism 9 pushes the pushing block 84 in the adjustable positioning mechanism 8.

[0042] like Figure 5 As shown, the lateral pushing mechanism 3 includes a receiving groove 31, a slider 32, a first spring 33 and a pushing bar 34, wherein the receiving groove 31 is opened on the inner wall of the placement groove 2, the slider 32 is slidably arranged on the inner side of the receiving groove 31, the first spring 33 is fixedly connected to the inner side of the slider 32, and the end of the first spring 33 away from the slider 32 is fixedly connected to the inner wall of the receiving groove 31, the pushing bar 34 is fixedly arranged on the top of the slider 32, and the pushing bar 34 is slidably arranged on the inner side of the placement groove 2.

[0043] By setting the above structure, when the push bar 34 is pushed, it slides inside the placement groove 2 and pushes the main board from the side of the main board. When the push bar 34 is no longer pushed, the compressed first spring 33 drives the push bar 34 to reset through the slider 32.

[0044] like Figure 6 As shown, the driving mechanism 4 includes a driving shaft 41, a driving gear 42, a knob 43 and a cross rib 44, wherein the driving shaft 41 passes through the tray 1 and extends to the bottom of the tray 1, and is rotatably connected to the tray 1 through a bearing, the driving gear 42 is fixedly sleeved on the outer bottom of the driving shaft 41, the knob 43 is fixedly set on the top of the driving shaft 41, and the cross rib 44 is fixedly set on the top of the knob 43.

[0045] By setting the above structure, when the knob 43 rotates, the driving gear 42 is driven to rotate through the driving shaft 41, so that the driving gear 42 drives the lifting mechanism 6.

[0046] like Figure 2 As shown, the lifting mechanism 6 includes a first screw rod 61, a driven gear 62 and a lifting plate 63, wherein the first screw rod 61 is rotatably nested at the inner center of the bottom shell 5 through a bearing, the driven gear 62 is fixedly sleeved at the outer bottom of the first screw rod 61 and meshed with the driving gear 42, and the lifting plate 63 is sleeved on the outer side of the first screw rod 61 and threadedly connected to the first screw rod 61.

[0047] By setting the above structure, when the driven gear 62 rotates, the first screw rod 61 is driven to rotate, and when the first screw rod 61 rotates, the lifting plate 63 is driven to rise or fall.

[0048] like Figure 2 As shown, the limiting mechanism 7 includes a limiting plate 71, a second screw 72 and an eccentric wheel 73, wherein the limiting plate 71 is fixedly arranged on the side of the lifting plate 63, the second screw 72 passes through the limiting plate 71 and is threadedly connected with the limiting plate 71, and the bottom end of the second screw 72 is rotatably nested on the inner wall of the bottom shell 5 through a bearing, and the eccentric wheel 73 is fixedly arranged on the top of the second screw 72, and the eccentric wheel 73 is in contact with the adjacent pushing bar 34.

[0049] By setting the above structure, when the limit plate 71 rises, the limit plate 71 drives the second screw 72 to rotate, and when the second screw 72 rotates, it drives the eccentric wheel 73 to rotate synchronously, so that the eccentric wheel 73 pushes the pushing bar 34, and the pushing bar 34 pushes the main board, thereby realizing the pre-positioning of the main board.

[0050] like Figure 3 and Figure 4 As shown, the adjustable positioning mechanism 8 includes an avoidance hole 81, a hollow positioning column 82, two sets of positioning components and a slide groove 88, and the positioning component includes a positioning push rod 83, a push block 84, a connecting sleeve 85, a sliding rod 86 and a second spring 87, wherein the avoidance hole 81 is opened at the bottom of the tray 1 and communicates with the placement slot 2, the hollow positioning column 82 is fixedly arranged on the top of the lifting plate 63 and extends to the inside of the avoidance hole 81, the positioning push rod 83 is slidably nested and arranged on the top of the side of the hollow positioning column 82, and the push block 84 It is fixedly arranged on the inner side of the positioning push rod 83, the connecting sleeve 85 is fixedly sleeved on the outer side of the push block 84, the sliding rod 86 is fixedly arranged on the outer side of the connecting sleeve 85, and is slidably nested on the inner wall of the hollow positioning column 82, the second spring 87 is sleeved on the outer side of the sliding rod 86, one end of the second spring 87 is fixedly connected to the connecting sleeve 85 and the other end is fixedly connected to the inner wall of the hollow positioning column 82, and two slide grooves 88 are provided, and the two slide grooves 88 are respectively opened at the bottom of both sides of the hollow positioning column 82.

[0051] By setting the above structure, the hollow positioning column 82 can drive the positioning push rod 83 to move upward and enter the positioning hole of the main board. Then, when the push block 84 is pushed, the push block 84 compresses the second spring 87 through the connecting sleeve 85, and drives the positioning push rod 83 to move outward, thereby realizing the positioning of the main board from the inside of the positioning hole. At the same time, when the push block 84 is no longer pushed, the second spring 87 can push the connecting sleeve 85, thereby causing the push block 84 to drive the positioning push rod 83 to reset.

[0052] like Figure 4As shown, the trigger mechanism 9 includes a fixed rod 91, a telescopic rod 92, a fixed collar 93, a third spring 94 and a trigger block 95, wherein the fixed rod 91 is slidably arranged on the inner side of the two slide grooves 88, and both ends thereof are fixedly connected to the inner wall of the avoidance hole 81, the telescopic rod 92 is fixedly arranged on the top of the fixed rod 91, the fixed collar 93 is fixedly sleeved on the outer side of the inner shaft of the telescopic rod 92, the third spring 94 is sleeved on the outer side of the telescopic rod 92, one end of the third spring 94 is fixedly connected to the fixed rod 91 and the other end is fixedly connected to the fixed collar 93, the trigger block 95 is fixedly connected to the top end of the inner shaft of the telescopic rod 92, and the trigger block 95 is fitted with the push block 84.

[0053] By setting the above structure, the trigger block 95 can push the push block 84 during the upward movement of the push block 84. At the same time, when the push block 84 cannot be pushed, the trigger block 95 cannot descend due to the obstruction of the push block 84. Therefore, the trigger block 95 will pull the inner shaft of the telescopic rod 92, thereby extending the inner shaft of the telescopic rod 92. When the inner shaft of the telescopic rod 92 extends, the third spring 94 is pulled through the fixing ring 93, so that when the subsequent trigger block 95 is no longer limited, the third spring 94 can drive the telescopic rod 92 to reset through the fixing ring 93.

[0054] Example 2

[0055] The present invention also provides a positioning method for an SMT positioning fixture, which specifically comprises the following steps:

[0056] S1, place the main board inside the placement slot 2, and tin the main board, then rotate the knob 43, so that the knob 43 drives the driving gear 42 to rotate through the driving shaft 41, and when the driving gear 42 rotates, it drives the first screw 61 through the driven gear 62, so that the first screw 61 drives the lifting plate 63 to rise;

[0057] S2, when the lifting plate 63 rises, the limiting plate 71 is driven to rise synchronously, and when the limiting plate 71 rises, the second screw 72 is driven to rotate, thereby causing the eccentric wheel 73 to rotate synchronously. When the eccentric wheel 73 rotates, the eccentric wheel 73 pushes the pushing bar 34, and then the two pushing bars 34 pre-position the main board from both sides;

[0058] S3, when the lifting plate 63 rises, the plurality of hollow positioning columns 82 are simultaneously driven to rise. When the hollow positioning columns 82 rise, their top ends gradually enter the positioning holes on the main board. When the hollow positioning columns 82 continue to rise, the push block 84 slides upward along the side wall of the trigger block 95. Then, under the push of the trigger block 95, the sliding rod 86 is compressed by the connecting sleeve 85, and the positioning push rod 83 is driven to slide outward.

[0059] S4, when the rising distance of the hollow positioning column 82 reaches the first threshold, the positioning push rod 83 fits with the inner wall of the positioning hole on the main board, the knob 43 is stopped at this time, and the mobile phone sub-board is mounted on the top of the tinned main board, and the hollow positioning column 82 and the two positioning push rods 83 synchronously pass through the positioning hole on the sub-board, thereby positioning the sub-board;

[0060] S5. Rotate the knob 43 again to make the hollow positioning column 82 continue to rise. When the rising distance of the hollow positioning column 82 reaches the second threshold, the two positioning push rods 83 can effectively position the main board and the sub-board from both sides of the positioning hole. Then, use this device to drive the main board and the sub-board through the furnace. After the furnace is passed, rotate the knob 43 in the opposite direction to synchronously reset the lateral pushing mechanism 3, the lifting mechanism 6, the limit mechanism 7 and the multiple adjustable positioning mechanisms 8. Finally, take out the welded main board and the sub-board from the inside of the placement slot 2.

[0061] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An SMT positioning fixture, comprising a tray (1), wherein a placement groove (2) is provided on the top of the tray (1), and wherein: Both ends of the inner side of the placement groove (2) are provided with lateral pushing mechanisms (3); the front side of the top of the tray (1) is provided with a driving mechanism (4); the bottom of the tray (1) is fixedly provided with a bottom shell (5); a lifting mechanism (6) is provided in the middle of the inner side of the bottom shell (5); both sides of the lifting mechanism (6) are provided with limiting mechanisms (7); the top of the lifting mechanism (6) is provided with a plurality of adjustable positioning mechanisms (8); and the plurality of adjustable positioning mechanisms (8) are provided with trigger mechanisms (9) inside. The driving gear (42) in the driving mechanism (4) drives the driven gear (62) in the lifting mechanism (6) to rotate, the lifting plate (63) in the lifting mechanism (6) drives the second screw (72) in the limiting mechanism (7) to rotate via the limiting plate (71) in the limiting mechanism (7), the eccentric wheel (73) in the limiting mechanism (7) pushes the pushing bar (34) in the lateral pushing mechanism (3), and the trigger block (95) in the trigger mechanism (9) pushes the pushing block (84) in the adjustable positioning mechanism (8); The adjustable positioning mechanism (8) comprises an avoidance hole (81), a hollow positioning column (82), two sets of positioning components and a slide groove (88); the positioning component comprises a positioning push rod (83), a push block (84), a connecting sleeve (85), a sliding rod (86) and a second spring (87); The avoidance hole (81) is provided at the bottom of the tray (1) and communicates with the placement groove (2); the hollow positioning column (82) is fixedly arranged at the top of the lifting plate (63) and extends to the inner side of the avoidance hole (81); the positioning push rod (83) is slidably nested at the top of the side of the hollow positioning column (82); the push block (84) is fixedly arranged at the inner side of the positioning push rod (83); the connecting sleeve (85) is fixedly sleeved at the outer side of the push block (84); the sliding rod (86) is fixedly arranged at the outer side of the connecting sleeve (85) and slidably nested on the inner wall of the hollow positioning column (82); the second spring (87) is sleeved at the outer side of the sliding rod (86); one end of the second spring (87) is fixedly connected to the connecting sleeve (85) and the other end is fixedly connected to the inner wall of the hollow positioning column (82); two slide grooves (88) are provided, and the two slide grooves (88) are respectively provided at the bottom of both sides of the hollow positioning column (82); The trigger mechanism (9) comprises a fixed rod (91), a telescopic rod (92), a fixed collar (93), a third spring (94) and a trigger block (95); The fixed rod (91) is slidably arranged inside the two slide grooves (88), and both ends thereof are fixedly connected to the inner wall of the avoidance hole (81); the telescopic rod (92) is fixedly arranged on the top of the fixed rod (91); the fixed collar (93) is fixedly sleeved and arranged on the outside of the inner shaft of the telescopic rod (92); the third spring (94) is sleeved and arranged on the outside of the telescopic rod (92); one end of the third spring (94) is fixedly connected to the fixed rod (91) and the other end is fixedly connected to the fixed collar (93); the trigger block (95) is fixedly connected to the top of the inner shaft of the telescopic rod (92); and the trigger block (95) is fitted with the push block (84).

2. The SMT positioning fixture according to claim 1, characterized in that: The lateral pushing mechanism (3) comprises a receiving groove (31), a sliding block (32), a first spring (33) and a pushing bar (34); The receiving groove (31) is formed on the inner wall of the placement groove (2); the slider (32) is slidably arranged inside the receiving groove (31); the first spring (33) is fixedly connected to the inner side of the slider (32); one end of the first spring (33) away from the slider (32) is fixedly connected to the inner wall of the receiving groove (31); the pushing bar (34) is fixedly arranged on the top of the slider (32); and the pushing bar (34) is slidably arranged inside the placement groove (2).

3. The SMT positioning fixture according to claim 2, characterized in that: The driving mechanism (4) comprises a driving shaft (41), a driving gear (42), a knob (43) and a cross convex strip (44); The driving shaft (41) passes through the tray (1) and extends to the bottom of the tray (1), and is rotatably connected to the tray (1) via a bearing; the driving gear (42) is fixedly sleeved on the outer bottom of the driving shaft (41); the knob (43) is fixedly disposed on the top of the driving shaft (41); and the cross rib (44) is fixedly disposed on the top of the knob (43).

4. The SMT positioning fixture according to claim 3, characterized in that: The lifting mechanism (6) comprises a first screw rod (61), a driven gear (62) and a lifting plate (63); The first screw rod (61) is rotatably nested in the center of the inner side of the bottom shell (5) via a bearing, the driven gear (62) is fixedly sleeved on the outer bottom of the first screw rod (61) and meshes with the driving gear (42), and the lifting plate (63) is sleeved on the outer side of the first screw rod (61) and is threadedly connected to the first screw rod (61).

5. The SMT positioning fixture according to claim 4, characterized in that: The limiting mechanism (7) comprises a limiting plate (71), a second screw rod (72) and an eccentric wheel (73); The limiting plate (71) is fixedly arranged on the side of the lifting plate (63); the second screw rod (72) passes through the limiting plate (71) and is threadedly connected to the limiting plate (71); the bottom end of the second screw rod (72) is rotatably nested on the inner wall of the bottom shell (5) through a bearing; the eccentric wheel (73) is fixedly arranged on the top end of the second screw rod (72); and the eccentric wheel (73) is in contact with the adjacent pushing bar (34).

6. A positioning method for an SMT positioning fixture according to any one of claims 1 to 5, characterized in that: The specific steps include: S1, placing the main board inside the placement groove (2), and tinning the main board, then rotating the knob (43), so that the knob (43) drives the driving gear (42) to rotate through the driving shaft (41), and when the driving gear (42) rotates, it drives the first screw rod (61) through the driven gear (62), so that the first screw rod (61) drives the lifting plate (63) to rise; S2, when the lifting plate (63) rises, it drives the limiting plate (71) to rise synchronously, and when the limiting plate (71) rises, it drives the second screw (72) to rotate, thereby causing the eccentric wheel (73) to rotate synchronously. When the eccentric wheel (73) rotates, the eccentric wheel (73) pushes the pushing bar (34), and then the two pushing bars (34) pre-position the main board from both sides; S3, when the lifting plate (63) rises, the plurality of hollow positioning columns (82) are synchronously driven to rise, and when the hollow positioning columns (82) rise, the top ends thereof gradually enter the positioning holes on the main board, and when the hollow positioning columns (82) continue to rise, the push block (84) slides upward along the side wall of the trigger block (95), and then, under the push of the trigger block (95), the sliding rod (86) is compressed by the connecting sleeve (85), and the positioning push rod (83) is driven to slide outward; S4, when the rising distance of the hollow positioning column (82) reaches the first threshold, the positioning push rod (83) fits against the inner wall of the positioning hole on the main board, the knob (43) is stopped from rotating, and the mobile phone sub-board is mounted on the top of the tinned main board, the hollow positioning column (82) and the two positioning push rods (83) synchronously pass through the positioning hole on the sub-board, and then the sub-board is positioned; S5. The knob (43) is rotated again, so that the hollow positioning column (82) continues to rise. When the rising distance of the hollow positioning column (82) reaches the second threshold value, the two positioning push rods (83) can effectively position the main board and the auxiliary board from both sides of the positioning hole. Then, the main board and the auxiliary board are driven through the furnace by the device. After the furnace is passed, the knob (43) is reversely rotated, so that the lateral pushing mechanism (3), the lifting mechanism (6), the limit mechanism (7) and the plurality of adjustable positioning mechanisms (8) are synchronously reset. Finally, the welded main board and the auxiliary board can be taken out from the inside of the placement groove (2).

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