Short shrapnel

Abstract

A short spring piece is mounted on a printed circuit board, the short spring piece includes a base plate, a tensioning portion formed by reverse bending from the rear end of the base plate, an elastic arm formed by obliquely extending forward and upward from the tensioning portion, and a contact portion formed at the top of the elastic arm, the front end of the base plate forms a fixed portion fixed to the printed circuit board by soldering, and a free portion formed by extending backward from the fixed portion and not soldered to the printed circuit board, the tensioning portion is formed by reverse bending from the rear end of the free portion. The short spring piece of the present application is reduced in size and has good elastic force and yield.

Description

Technical Field

[0001] The present application relates to the field of electrical connectors, and in particular to a short spring piece. Background Art

[0002] CN202010200447.9 discloses a spring for radio frequency signal transmission. The spring disclosed in the background technology of the patent includes a welding substrate, a tensioning portion formed by reverse bending from one end of the substrate, a horizontal portion extending parallel to the top of the substrate from the tensioning portion, an elastic arm extending obliquely upward from the free end of the horizontal portion, and a support arm extending from the elastic arm toward the substrate. In the working state, the top of the elastic arm is pressed down by the object to be contacted, and the support end of the support arm slides on the upper surface of the substrate toward the tensioning portion.

[0003] The soldering substrate of the above-mentioned spring is mounted and soldered on the printed circuit board. The elastic force is provided by the tensioning part, the horizontal part and the elastic arm. This structure requires the spring to have a certain length to ensure the length of the horizontal part and the elastic arm to maintain the elastic force. Generally, the length of the spring needs to be 2.5mm and the height is 1.1mm. In the miniaturization design of the product, the design length of the spring needs to be further reduced to 1.5mm, and the height is not higher than 1mm. At this time, the design difficulty of the elastic force and yield of the spring product is extremely great. Utility Model Content

[0004] In view of this, it is necessary to provide a short spring sheet that can ensure good elastic force and yield while shortening the length and height of the spring sheet.

[0005] In order to solve the above technical problems, the present application provides a short spring piece, which is mounted on a printed circuit board. The short spring piece includes a substrate, a tensioning portion formed by reverse bending from the rear end of the substrate, an elastic arm extending obliquely forward and upward from the tensioning portion, and a contact portion formed at the top of the elastic arm. The front end of the substrate forms a fixed portion that is mounted and welded on the printed circuit board, and a free portion that extends backward from the fixed portion and is not welded and fixed to the printed circuit board. The tensioning portion is formed by reverse bending from the rear end of the free portion.

[0006] Preferably, in an initial state, the bottom surfaces of the fixing portion and the free portion are flush with each other and are in contact with the surface of the printed circuit board.

[0007] Preferably, the length of the free portion is 20%-30% of the length of the substrate.

[0008] Preferably, the length of the free portion is 25%-28% of the length of the substrate.

[0009] Preferably, the elastic arm includes a horizontal portion extending horizontally forward from the end of the tensioning portion, an inclined arm bent from the horizontal portion and extending obliquely forward and upward, and a bent portion formed at the connection between the horizontal portion and the inclined arm.

[0010] Preferably, the short spring sheet further comprises a support arm which is formed by bending reversely from the top end of the inclined arm and extending toward the substrate, and the end of the support arm extends to near the top of the substrate.

[0011] Preferably, the short spring piece also includes a wing portion formed by bending upward and extending from the two lateral sides of the fixed portion of the substrate, a pre-stressing hole is opened in the middle of the wing portion, and the support arm includes a support arm body and a pre-stressed end portion extending from the free end of the support arm body along the two lateral sides to the pre-stressing hole.

[0012] Preferably, the upper surface of the horizontal portion is flush with the upper surface of the wing portion.

[0013] Preferably, when the spring sheet is in a compressed working state, the bottom surface of the free portion is deformed and springs up in a direction away from the printed circuit board and provides elastic force.

[0014] Preferably, in a working state, the support arm moves backward and deforms to be close to the base plate, and the bent portion is located above the free end of the support arm.

[0015] The short spring sheet of the present application is formed by dividing the substrate along the length direction into a fixed portion welded and fixed to the printed circuit board and a free portion that is not welded and fixed to the printed circuit board. When pressed down, the free portion provides a certain elastic force, which can effectively improve the elastic force and the yield strength of the short spring sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 A three-dimensional diagram of the short shrapnel of this application;

[0018] Figure 2 For along Figure 1 A cross-sectional view of the dotted line AA;

[0019] Figure 3 This is a cross-sectional view of the short spring piece of the present application in the initial state and the working state;

[0020] Figure 4 for Figure 3 A partial enlarged view of the dotted circle shown.

[0021] Description of Reference Numerals

[0022] Short spring piece-10; substrate-11; fixed part-111; free part-112; bottom surface-1121,1121'; tensioning part-12; elastic arm-13; horizontal arm-131; inclined arm-132; contact part-133; contact protrusion-134; bending part-135; support arm-14; support arm body-141; pre-stressed end-142; wing-15; pre-stressing hole-151; printed circuit board-20. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of this application clearer, the technical solution of this application will be clearly and completely described below in combination with the specific embodiments of this application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of this application, not all of them.

[0024] This application is Figure 1 The X direction is shown as the right side in the horizontal direction, the Y direction is shown as the front side in the longitudinal direction, and the Z direction is shown as the top side in the vertical direction.

[0025] See also Figure 1 , Figure 2 As shown, the short spring piece 10 of the present application includes a substrate 11, an elastic arm 13 formed by reverse bending from the rear end of the substrate 11, a tensioning portion 12 formed at the bending point between the substrate 11 and the elastic arm 13, a support arm 14 formed by bending and extending from the end of the elastic arm 13 toward the substrate 11, and wing portions 15 formed by bending and extending upward from the lateral sides of the substrate 11.

[0026] The base plate 11 includes a fixed portion 111 located at the front side and a free portion 112 located at the rear side, and the wing portion 15 is formed by bending and extending upward from both lateral sides of the fixed portion 111. A pre-pressing hole 151 is provided in the middle part of the wing portion 15, and the pre-pressing hole 151 extends a certain length along the length direction. A horizontal surface is provided at the top of the pre-pressing hole 151, and an arc surface is provided between the top and the front of the pre-pressing hole 151.

[0027] The tensioning portion 12 is formed by reverse bending from the rear end of the free portion 112. The elastic arm 13 includes a horizontal portion 131 formed by horizontally extending forward from the tensioning portion 12 above the substrate 11, an inclined arm 132 formed by obliquely extending forward and upward from the horizontal portion 131, a contact portion 133 formed at the top of the inclined arm 132, and a bent portion 135 formed at the junction of the inclined arm 132 and the horizontal portion 131. The support arm 14 is formed by reverse bending from the end of the contact portion 133 and extending toward the substrate 11. The support arm 141 includes a support arm body 141 extending above the substrate 11 and a pre-pressed end portion 142 formed by extending from the end of the support arm body 141 along both sides in the horizontal direction and received in the pre-pressing hole 151.

[0028] The contact portion 133 is punched upward at the bending position between the tilt arm 132 and the support arm 141 to form a contact protrusion 134 , and the contact protrusion 134 is higher than the surface of the contact portion 133 .

[0029] Please continue reading Figures 2 to 4 As shown, the fixed portion 111 is mounted on the printed circuit board 20, while the free portion 112 is not fixed on the printed circuit board 20 to be in a free state. The length of the fixed portion 111 is h1, and the length of the free portion 112 is h2. The length h2 of the free portion 112 is 20%-30% of the length of the spring 10, preferably 25%-28%. The length h1 of the fixed portion 111 is 70%-80% of the length of the spring 10, preferably 72%-75%. Specifically in this embodiment, the length of the spring 10 is 1.5mm, and the length of the free portion 112 is 0.4mm.

[0030] Key References Figure 3 , Figure 4 As shown, the docking object presses the contact portion 133 downward, causing the elastic arm 13 and the support arm 14 to be pressed downward and deformed until the working state shown by the dotted line. At this time, the support arm 14 moves backward from the substrate 11, and the bent portion 135 is now located above the support arm 14 without contacting it, while the bottom surface 1121 of the free portion 112 is lifted upward away from the printed circuit board 20. At this time, the bottom surface 1121' of the free portion 112 in the working state is deformed upward and a gap is generated between the free portion 112 and the printed circuit board 20. Therefore, the free portion 112 can provide a part of the elastic force to support the elastic arm 13, and at the same time, it can improve the yield strength of the elastic arm 13 to avoid yield failure of the product due to size reduction.

[0031] The length of the spring piece 10 in this embodiment is 1.5 mm, and the spring height is 1.0 mm. The applicant conducted the following two sets of simulation experiments, and the experimental process and data are as follows:

[0032] 1. The length of the fixed portion 111 of the spring sheet 10 substrate 11 is set to 1.35 mm (the length of the free portion 112 is 0.15 mm), the spring height is 1.0 mm, the fixed portion 111 is welded and fixed on the printed circuit board 20, and the free portion 112 is close to the printed circuit board 20 without welding. During the verification, the elastic arm 13 is compressed downward by 0.60 mm to the lowest working height, and then rebounds to a working height of 0.75 mm. The return force is 0.431 N, and the spring sheet yields 0.1088 mm.

[0033] 2. The length of the fixed portion 111 of the spring sheet 10 substrate 11 is set to 1.1 mm (the length of the free portion 112 is 0.4 mm), the spring height is 1.0 mm, the fixed portion 111 is welded and fixed on the printed circuit board 20, and the free portion 112 is close to the printed circuit board 20 without welding. During the verification, the elastic arm 13 is compressed downward by 0.60 mm to the lowest working height, and then rebounds to a working height of 0.75 mm. The return force is 0.473 N, and the spring sheet yields 0.0688 mm.

[0034] Through the above simulation experiments, the design of Experiment 2 is better.

[0035] The short spring piece 10 of the present application is formed by dividing the substrate 11 along the length direction into a fixed portion 111 welded and fixed to the printed circuit board and a free portion 112 not welded and fixed to the printed circuit board 20. When pressed down, the free portion 112 provides a certain elastic force, which can effectively improve the elastic force and the yield strength of the short spring piece 10.

[0036] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0037] The above embodiments only express the preferred implementation of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A short spring piece mounted on a printed circuit board, the short spring piece comprising a substrate, a tensioning portion formed by reverse bending from the rear end of the substrate, an elastic arm extending obliquely forward and upward from the tensioning portion, and a contact portion formed at the top of the elastic arm, characterized in that: The front end of the substrate forms a fixed portion fixed to the printed circuit board by mounting and welding, and a free portion extending backward from the fixed portion and not welded and fixed to the printed circuit board. The tensioning portion is formed by reverse bending from the rear end of the free portion.

2. The short spring sheet according to claim 1, characterized in that: In an initial state, the bottom surfaces of the fixed portion and the free portion are flush with each other and are in contact with the surface of the printed circuit board.

3. The short spring sheet according to claim 2, characterized in that: The length of the free portion is 20%-30% of the length of the substrate.

4. The short spring sheet according to claim 3, characterized in that: The length of the free portion is 25%-28% of the length of the substrate.

5. The short spring sheet according to claim 4, characterized in that: The elastic arm includes a horizontal portion extending horizontally forward from the end of the tensioning portion, an inclined arm bent from the horizontal portion and extending obliquely forward and upward, and a bent portion formed at the connection between the horizontal portion and the inclined arm.

6. The short spring sheet according to claim 5, characterized in that: The short spring sheet further comprises a support arm which is formed by bending reversely from the top end of the inclined arm and extending toward the substrate, and the end of the support arm extends to a position close to the top of the substrate.

7. The short spring sheet according to claim 6, characterized in that: The short spring sheet also includes a wing portion that is bent and extended upward from both lateral sides of the fixed portion of the substrate, and a pre-stressed hole is opened in the middle of the wing portion. The support arm includes a support arm body and a pre-stressed end portion that extends from the free end of the support arm body along both lateral sides to the pre-stressed hole.

8. The short spring sheet according to claim 7, characterized in that: The upper surface of the horizontal portion is flush with the upper surface of the wing portion.

9. The short spring sheet according to claim 6, characterized in that: When the short spring sheet is in a compressed working state, the bottom surface of the free portion is deformed and bounces up in a direction away from the printed circuit board and provides elastic force.

10. The short spring sheet according to claim 9, characterized in that: In the working state, the support arm moves backward and deforms to be close to the base plate, and the bent portion is located above the free end of the support arm.

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