Bottom plate for ultrathin keyboard

Abstract

The utility model discloses a bottom plate used for an ultrathin keyboard, the bottom plate is composed of a metal support plate and an injection molding bottom plate which are combined with each other, the injection molding bottom plate is provided with a plurality of key switch assembling units, the injection molding bottom plate is formed on the metal support plate through injection molding, and a hollow stress isolation groove is formed on the injection molding bottom plate. The method is used for eliminating bulging of an injection molding bottom plate caused by different thermal expansion coefficients between a metal supporting plate and the injection molding bottom plate. The hollow stress isolation groove is formed in the injection molding bottom plate, so that the problem of stress concentration generated during injection molding is better solved, and the problem that the injection molding bottom plate bulges due to different thermal expansion coefficients between the metal supporting plate and the injection molding bottom plate is solved.

Description

Technical Field

[0001] The utility model relates to a circuit board injection molding structure, in particular to a bottom plate used for an ultra-thin keyboard. Background Art

[0002] During the injection molding process, plastic is injected into the mold at high temperature and then cooled to solidify. Since the thermal expansion coefficient of plastic and metal differs by 5-10 times, this means that plastic deforms much more than metal during heating or cooling. Especially in the manufacturing process of plastic parts with metal inserts, this difference can lead to significant shrinkage mismatch problems.

[0003] Specifically, the inner layer of plastic around the metal will be subject to compressive stress due to the constraint of the metal when the plastic shrinks. On the outer layer of plastic, the outer layer of plastic will be stretched due to the shrinkage of the inner layer of plastic, thus generating tensile stress. The combined effect of this compressive stress and tensile stress will cause stress concentration around the metal. This stress concentration may not only cause deformation or cracking of plastic parts, but also affect the mechanical properties and durability of plastic parts.

[0004] In addition, due to the difference in thermal expansion coefficients between plastic and metal, when plastic parts are injected on metal base plates, bulging may occur. This is because during the cooling process, the plastic shrinks more than the metal base plate, causing the connection part of the plastic part on the base plate to deform and form bulges. This bulge not only affects the appearance quality of the product, but may also affect the assembly and performance of the product.

[0005] Therefore, in the plastic injection molding process, how to effectively reduce stress concentration and bulge problems and improve the quality and performance of plastic parts is the main problem to be solved in this application. Utility Model Content

[0006] In view of the above problems, the utility model aims to provide a bottom plate for an ultra-thin keyboard which can solve the stress concentration problem.

[0007] To achieve the technical purpose, the solution of the utility model is: a base plate for an ultra-thin keyboard, the base plate is composed of a metal support plate and an injection-molded base plate combined with each other, the injection-molded base plate has a plurality of assembly units for assembling key switches, the injection-molded base plate is injection-molded on the metal support plate, and a hollow stress isolation groove is constructed on the injection-molded base plate to eliminate the bulge of the injection-molded base plate caused by the different thermal expansion coefficients between the metal support plate and the injection-molded base plate.

[0008] Preferably, the stress isolation grooves on the injection molded bottom plate are arranged around the periphery of each assembly unit.

[0009] Preferably, a through hole is provided at the connection point between two adjacent stress isolation grooves, and a central connecting line of the two adjacent through holes is parallel to the stress acting direction.

[0010] Preferably, at least one connection point is provided between two adjacent assembly units.

[0011] Preferably, the connection point is an elliptical structure, and the connection point is bonded to the surfaces of two adjacent assembly units.

[0012] Preferably, the major axis of the elliptical structure of the connection point is parallel to the direction of stress action.

[0013] Preferably, a plurality of stress dispersion holes are evenly arranged on each of the assembly units.

[0014] Preferably, the metal support plate is provided with injection holes corresponding to the stress dispersion holes.

[0015] The beneficial effect of the utility model is that by constructing a hollow stress isolation groove on the injection molding bottom plate, the stress concentration problem generated during injection molding is better dissipated, and the bulging problem of the injection molding bottom plate caused by the different thermal expansion coefficients between the metal support plate and the injection molding bottom plate is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model;

[0017] Figure 2 It is an exploded view of the utility model;

[0018] Figure 3 It is a structural schematic diagram of the plastic bottom plate in the utility model;

[0019] Figure 4 It is a structural schematic diagram of an injection molded base plate in the prior art.

[0020] In the figure: 1. Metal support plate; 2. Injection molded bottom plate; 201. Assembly unit; 202. Stress isolation groove; 203. Connection point; 204. Through hole; 205. Stress dispersion hole; 3. Push switch. DETAILED DESCRIPTION

[0021] The utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. In order to clearly and completely describe the technical solution, the following embodiments are selected for illustration; the following embodiments are part of the embodiments of the utility model; based on this application, other embodiments obtained without creative work are all within the scope of protection of the utility model.

[0022] In the following embodiments, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer", "top / bottom" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of clearly describing the present embodiment, rather than indicating or implying that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation on the present application. At the same time, "first" and "second" in the embodiments are only used for distinguishing description purposes, and do not represent or imply relative importance.

[0023] like Figure 1-3 As shown, the specific embodiment of the utility model is a base plate for an ultra-thin keyboard, the base plate is composed of a metal support plate 1 and an injection molded base plate 2 that are combined with each other, and the injection molded base plate 2 has a plurality of assembly units for installing key switches 3, each assembly unit corresponds to an assembly of a key switch, Figure 2 For the sake of convenience, only one key switch is shown. The injection molded bottom plate 2 is injection molded on the metal support plate 1. A hollow stress isolation groove 202 is configured on the injection molded bottom plate 2 to eliminate the bulge of the injection molded bottom plate 2 caused by the different thermal expansion coefficients between the metal support plate 1 and the injection molded bottom plate 2. Figure 4 As shown, the base plate in the prior art is integrally injection molded, and during the injection molding, the injection molded base plate 2 is easily raised on the metal support plate 1 due to the different thermal expansion coefficients of plastic and metal.

[0024] In a specific embodiment of the present application, a single button mold injection molding method is adopted to solve the deformation and strength problems. Specifically, the stress isolation groove 202 on the injection molding base plate 2 is arranged around each assembly unit 201.

[0025] In order to optimize the design, the stress isolation groove 202 is in the shape of a long strip, so as to ensure the injection strength and reduce the use of materials. In order to avoid stress cracking, a through hole 204 is provided at the connection point between two adjacent stress isolation grooves 202, and the center connecting line of the two adjacent through holes 204 is parallel to the direction of stress action. Preferably, the through hole 204 is an elliptical hole or a circular hole. When an elliptical hole is adopted, the long axis of the elliptical hole is parallel to the direction of stress action; if a circular hole is opened, a process circular hole of equal diameter is added, and the center connecting line of the two adjacent circular holes is parallel to the direction of stress action, so as to better dissipate the internal stress structure. In addition, a plurality of stress dispersion holes 205 are evenly arranged around each assembly unit 201 to disperse the internal stress. At the same time, the presence of the stress dispersion holes 205 also facilitates the exhaust and demolding during the injection molding process, and improves the smoothness of the manufacturing process. Injection holes corresponding to the stress dispersion holes 205 are opened on the metal support plate to facilitate manufacturing and assembly.

[0026] In order to enhance the overall strength, at least one connection point 203 is provided between two adjacent assembly units 201. The connection point 203 is an elliptical structure and is bonded to the surfaces of the two adjacent assembly units 201. The long axis of the elliptical structure of the connection point 203 is parallel to the direction of stress.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent substitutions and improvements made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A base plate for an ultra-thin keyboard, the base plate being composed of a metal support plate and an injection-molded base plate combined with each other, the injection-molded base plate having a plurality of assembly units for assembling key switches, the injection-molded base plate being injection-molded on the metal support plate, characterized in that: A hollow stress isolation groove is constructed on the injection molding bottom plate to eliminate the bulging of the injection molding bottom plate caused by the different thermal expansion coefficients between the metal support plate and the injection molding bottom plate.

2. The base plate for an ultra-thin keyboard according to claim 1, characterized in that: The stress isolation grooves on the injection molded bottom plate are arranged around the periphery of each assembly unit.

3. The base plate for an ultra-thin keyboard according to claim 2, characterized in that: The stress isolation groove is in the shape of an elongated strip, and a through hole is provided at the connecting point of two adjacent stress isolation grooves, and the central connecting line of the two adjacent through holes is parallel to the stress acting direction.

4. The base plate for an ultra-thin keyboard according to claim 2, characterized in that: At least one connection point is provided between two adjacent assembly units.

5. The base plate for an ultra-thin keyboard according to claim 4, characterized in that: The connection point is an elliptical structure, and the connection point is bonded to the surfaces of two adjacent assembly units.

6. The base plate for an ultra-thin keyboard according to claim 5, characterized in that: The major axis of the elliptical structure of the connection point is parallel to the stress acting direction.

7. The base plate for an ultra-thin keyboard according to claim 2, characterized in that: A plurality of stress dispersion holes are evenly arranged on each of the assembly units.

8. The base plate for an ultra-thin keyboard according to claim 7, characterized in that: The metal support plate is provided with injection holes corresponding to the stress dispersion holes.

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