An ultrasonic welding tool suitable for protective shells of nanocrystalline magnetic core injection molded parts

Abstract

The utility model discloses an ultrasonic welding tool suitable for a protective shell of a nanocrystalline magnetic core injection molded part, comprising an upper die welding head and a lower die positioning base, the product to be welded is located between the upper die welding head and the lower die positioning base, the upper die welding head is a stepped variable amplitude welding head, the circumferential direction is an octahedral structure, comprising a long plane, a short plane and an arc transition surface therebetween arranged alternately in sequence, a first step and a second step and an inward concave transition arc surface therebetween are arranged on the side of the long plane, a reserved hole is arranged at the bottom of the upper die welding head, the lower die positioning base comprises a bottom plate and a positioning frame, the positioning frame is provided with a profiling groove matching the shape of the product to be welded, and the upper die welding head is externally connected to an ultrasonic generating device. The upper die welding head designed by the utility model through finite element simulation meets the natural frequency requirements of ultrasonic welding, the tooling is easy to operate, has high reliability, strong repeatability, stable welding quality, and the upper and lower dies of the tooling are designed with profiling structures, which can be well adapted to the product.

Description

Technical Field

[0001] The utility model belongs to the technical field of soft magnetic core testing tooling, and in particular relates to an ultrasonic welding tooling suitable for a protective shell of a nanocrystalline magnetic core injection molding part. Background Art

[0002] Nanocrystalline magnetic core components are often used in power control and inverters of new energy electric vehicles, and are convenient to install directly on PCB boards. They are installed between the inverter and the motor to filter out high-frequency noise and protect the inverter and motor bearings. They are widely used in new energy electric vehicle powertrains and charging stations, allowing vehicles to pass EMC tests. Due to the complex structure of nanocrystalline magnetic core inductor filter products used in new energy electric vehicles, the mechanical strength of the annular magnetic core body is low, and they need to be placed in injection molded parts for protection. The shell and shell cover of the injection molded protective shell need to be sealed reliably and have certain pull-out force requirements. The traditional process uses a snap-on structure to achieve the seal between the shell and shell cover of the injection molded protective shell, but the pull-out force between the shell and shell cover obtained in this way is not enough to meet the requirements.

[0003] Ultrasonic welding is a process in which high-frequency vibration waves are transmitted to the surfaces of two objects to be welded. Under pressure, the two surfaces of the objects rub against each other to form a fusion between the molecular layers. Ultrasonic welding is more and more widely used because it is well suited for injection molding welding and has stable welding quality. Therefore, injection molding can adopt ultrasonic welding as a reliable and strong sealing method. In the ultrasonic welding system, the structure of the welding head has a great influence on the welding quality. Therefore, it is necessary to develop a corresponding ultrasonic welding tooling for the product to ensure stable welding quality, which is of great significance. Utility Model Content

[0004] In view of the above-mentioned problems, the utility model provides an ultrasonic welding tool suitable for a protective shell of a nanocrystalline magnetic core injection molded part, which meets the product welding quality requirements.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] An ultrasonic welding tool suitable for a protective shell of a nanocrystalline magnetic core injection molded part, comprising an upper mold welding head and a lower mold positioning base, wherein a product to be welded is located between the upper mold welding head and the lower mold positioning base, wherein the upper mold welding head is a stepped variable amplitude welding head, and the circumference of the upper mold welding head is an octahedral structure, comprising long planes and short planes alternately arranged in sequence, an arc-shaped transition surface is arranged between the long plane and the short plane, a first step and a second step are arranged on the long plane side, and an inner concave transition arc surface is arranged between the first step and the second step for transition, a reserved hole is arranged at the bottom of the upper mold welding head, the lower mold positioning base comprises a bottom plate and a positioning frame arranged on the bottom plate, the positioning frame is a contouring tool, and a contouring groove matching the shape of the product to be welded is arranged on the positioning frame, and the upper mold welding head is externally connected to an ultrasonic generating device.

[0007] According to a further technical solution, the product to be welded includes an upper cover and an injection molded part body, wherein the injection molded part body is an annular groove structure having an annular cavity for accommodating the nanocrystalline magnetic core.

[0008] According to a further technical solution, corresponding welding edges are respectively provided on the upper cover and the injection molded part body, and the corresponding welding edges can be welded together during ultrasonic welding.

[0009] According to a further technical solution, a positioning column is provided on the upper cover, and a reserved hole at the bottom of the upper mold welding head corresponds to the positioning column.

[0010] According to a further technical solution, a side bearing mechanism is provided on the injection molded part body, which is the location for mounting the PCB board.

[0011] According to a further technical solution, the size of the contoured groove is 0.1 mm larger than the outer dimensions of the product to be welded, so as to facilitate product assembly and removal.

[0012] Principle of ultrasonic plastic welding: When ultrasonic waves act on the contact surface of thermoplastic plastics, high-frequency vibrations of tens of thousands of times per second will be generated. This high-frequency vibration with a certain amplitude transmits ultrasonic energy to the welding area through the upper weldment. Since the welding area, i.e., the interface between the two welds, has a large acoustic resistance, local high temperature will be generated. Due to the poor thermal conductivity of plastics, it cannot be dissipated in time and gathers in the welding area, causing the contact surface of the two plastics to melt rapidly. After a certain pressure is applied, it is fused into one. When the ultrasonic wave stops acting, the pressure is allowed to continue for a few seconds to solidify and form, thus forming a strong molecular chain to achieve the purpose of welding, and the welding strength can be close to the strength of the raw materials. The quality of ultrasonic plastic welding depends on three factors: the amplitude of the transducer welding head, the applied pressure and the welding time. The welding time and welding head pressure can be adjusted, and the amplitude is determined by the transducer and the amplitude rod.

[0013] The upper die welding head designed by the utility model through finite element simulation meets the natural frequency requirements of ultrasonic welding, and can well meet the ultrasonic welding of the protective shell of the injection molded parts of the nanocrystalline magnetic core for new energy electric vehicles; the tooling is easy to operate, has high reliability, strong repeatability, and stable welding quality; the upper and lower dies of the tooling are designed with a contoured structure, which can well adapt to the product.

[0014] The upper die welding head of the utility model adopts a stepped variable cross-section setting, which can further reduce the weight of the welding head under the premise of ensuring the natural frequency, and ensure that the amplitude is uniform on the welding surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the overall structure of the ultrasonic welding tooling of the utility model;

[0016] Figure 2 This is a schematic diagram of the ultrasonic welding tooling structure of the utility model (products omitted);

[0017] Figure 3 This is a front view of the upper die welding head of the utility model;

[0018] Figure 4 It is a side view of the upper die welding head of the utility model;

[0019] Figure 5 It is a top view of the upper die welding head of the utility model;

[0020] Figure 6 This is a bottom view of the upper die welding head of the utility model;

[0021] Figure 7 This is a schematic diagram of the lower mold positioning base structure of the utility model;

[0022] Figure 8 This is a top view of the lower mold positioning base of the utility model;

[0023] Fig. 9 It is a schematic diagram of the upper cover structure of the product to be welded in the utility model;

[0024] Fig.10 This is a schematic diagram of the main structure of the injection molded part of the product to be welded in the utility model;

[0025] Fig.11 This is a schematic diagram of the cooperation between the product to be welded and the lower die positioning base of the utility model;

[0026] Fig.12 This is a welding process flow chart of the ultrasonic welding tooling of the utility model;

[0027] In the figure: 1. upper die welding head; 11. long plane; 12. short plane; 13. arc transition surface; 14. first step; 15. second step; 16. concave transition arc surface; 17. reserved hole; 2. lower die positioning base; 21. bottom plate; 22. positioning frame; 23. contour groove; 3. product to be welded; 31. upper cover; 311. positioning column; 32. injection molded part body; 33. annular cavity. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the utility model.

[0029] like Figure 1-Figure 6 As shown, an ultrasonic welding tool suitable for a protective shell of a nanocrystalline magnetic core injection molded part comprises an upper die welding head 1 and a lower die positioning base 2, a product 3 to be welded is located between the upper die welding head 1 and the lower die positioning base 2, the upper die welding head 1 is a stepped variable amplitude welding head, through finite element simulation, the circumferential direction of the upper die welding head 1 is an octahedral structure, comprising long planes 11 and short planes 12 alternately arranged in sequence, an arc-shaped transition surface 13 is arranged between the long plane 11 and the short plane 12, a first step 14 and a second step 15 are arranged on the side of the long plane 11, an inner concave transition arc surface 16 is arranged between the first step 14 and the second step 15 for transition, the upper die welding head 1 is externally connected to an ultrasonic generating device, and a reserved hole 17 is arranged at the bottom of the upper die welding head 1.

[0030] like Figure 7-Figure 8 As shown, the lower mold positioning base 2 includes a bottom plate 21 and a positioning frame 22 arranged on the bottom plate 21. The positioning frame 22 is a contouring tooling, and a contouring groove 23 matching the shape of the product 3 to be welded is provided on the positioning frame 22 for positioning the product 3 to be welded.

[0031] like Figure 9-11 As shown, the product 3 to be welded includes an upper cover 31 and an injection molded body 32. The injection molded body 32 is an annular groove structure, and has an annular cavity 33 for accommodating the nanocrystalline magnetic core. The upper cover 31 and the injection molded body 32 are respectively provided with corresponding welding edges, and the corresponding welding edges can be welded together during ultrasonic welding. The upper cover 31 is provided with a positioning column 311, and the reserved hole 17 at the bottom of the upper mold welding head 1 corresponds to the positioning column 311.

[0032] In ultrasonic welding equipment, the process parameters that affect welding quality are mainly amplitude, welding time, welding pressure, etc. The upper mold stepped variable amplitude welding head of the utility model is simulated by finite element software: the natural frequency is 20KHZ, and the maximum amplitude is 80μm. The natural frequency and amplitude of the tooling are adapted to the welding requirements of injection molded parts, ensuring the stability of welding quality. The lower mold is a surface hardening profiling tooling, which is fixed with threaded holes and bolts to ensure that the product is assembled into the restricted position in the tooling and the flatness of the product is guaranteed. There is no need to use additional tools to press the product. The size of the profiling groove 23 is 0.1mm larger than the product's outer size, which is convenient for product assembly and removal.

[0033] The specific steps of plastic ultrasonic welding of the utility model are as follows Fig.12 As shown, it mainly includes: the first step: placing the plastic part; the second step: the welding head contacts the plastic part; the third step: applying pressure; the fourth step: melting process; the fifth step: pressure holding process; the sixth step: withdrawing the welding head.

[0034] The upper die welding head designed by the utility model through finite element simulation meets the natural frequency requirements of ultrasonic welding, and can well meet the ultrasonic welding of the protective shell of the injection molded parts of the nanocrystalline magnetic core for new energy electric vehicles; the tooling is easy to operate, has high reliability, strong repeatability, and stable welding quality; the upper and lower dies of the tooling are designed with a contoured structure, which can well adapt to the product.

[0035] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. An ultrasonic welding tool suitable for the protective shell of nanocrystalline magnetic core injection molding, characterized in that: The invention comprises an upper die welding head (1) and a lower die positioning base (2), wherein a product (3) to be welded is located between the upper die welding head (1) and the lower die positioning base (2), wherein the upper die welding head (1) is a stepped variable amplitude welding head, and the upper die welding head (1) is an octahedral structure in the circumferential direction, comprising long planes (11) and short planes (12) arranged alternately in sequence, wherein an arc-shaped transition surface (13) is arranged between the long plane (11) and the short plane (12), and a first step (14) is arranged on the side of the long plane (11). ) and a second step (15), an inwardly concave transition arc surface (16) is provided between the first step (14) and the second step (15) for transition, a reserved hole (17) is provided at the bottom of the upper die welding head (1), the lower die positioning base (2) comprises a bottom plate (21) and a positioning frame (22) arranged on the bottom plate (21), the positioning frame (22) is a contouring tooling, and a contouring groove (23) matching the shape of the product (3) to be welded is provided on the positioning frame (22).

2. The ultrasonic welding tooling for the protective shell of the nanocrystalline magnetic core injection molded part according to claim 1 is characterized in that: The upper die welding head (1) is externally connected to an ultrasonic generating device, and the bottom plate (21) is provided with threaded holes for fixing.

3. The ultrasonic welding tooling for the protective shell of the nanocrystalline magnetic core injection molded part according to claim 1 is characterized in that: The product (3) to be welded comprises an upper cover (31) and an injection molded part body (32); the injection molded part body (32) is an annular groove structure having an annular cavity (33) for accommodating a nanocrystalline magnetic core.

4. The ultrasonic welding tooling for the protective shell of the nanocrystalline magnetic core injection molded part according to claim 3 is characterized in that: The upper cover (31) and the injection molded part body (32) are respectively provided with corresponding welding edges, and the corresponding welding edges can be welded together during ultrasonic welding.

5. The ultrasonic welding tooling for the protective shell of the nanocrystalline magnetic core injection molded part according to claim 3 is characterized in that: A positioning column (311) is provided on the upper cover (31), and a reserved hole (17) at the bottom of the upper die welding head (1) corresponds to the positioning column (311).

6. The ultrasonic welding tooling for the protective shell of the nanocrystalline magnetic core injection molded part according to claim 2, characterized in that: The size of the contoured groove (23) is 0.1 mm larger than the outer dimensions of the product (3) to be welded, so as to facilitate the assembly and removal of the product.

Images