RU204109U1 - PCB frame - Google Patents

Abstract

The utility model relates to the field of electrical engineering, in particular to the structural elements of radio electronic equipment units. The technical result consists in increasing the mechanical strength of the printed circuit assembly while simplifying the layout of the radio-electronic unit and ensuring high-quality heat removal for the placed electronic radio products. It is achieved by the fact that in the frame of the printed circuit assembly, which consists of metal frames with detachable connectors connected in a package, each frame is equipped with one heat sink side, intersecting in the center with longitudinal and transverse stiffeners, as well as an additional stiffener passing along the perimeter of the frame, while on at the junction of the screen and the frame, as well as on the longitudinal and transverse stiffeners, there are fastening holes and, formed in the form of a thickening of the material and intended for additional fixation of the printed circuit assembly, in addition, in the corners of the frame and in the middle of each side of the frame there are through holes intended for constructive interfacing of several printed circuit assemblies; in the heat-dissipating side of at least one frame, two fastening holes of the electronic equipment unit are provided for mounting the printed circuit assembly on the surface of the on-board thermoregulation system. 7 ill.

Description

The utility model refers to the structural elements of radio electronic equipment (REA) units, namely to the elements built according to the modular principle, in which the metal parts-bases of the electronic modules are part of the radio-electronic unit housing, and can be used to create electronic modules that are assembled into on-board units. electronic equipment and exposed to intense mechanical stress.

The modular principle of constructing radio-electronic units using frame structures for installing printed circuits is widely known now and is actively used in the construction of on-board radio-electronic equipment.

The known design of the block of electronic equipment according to US Pat. RF 2365070, N05K 1/00, N05K 5/06, N05K 7/14 , which implements the modular principle of construction. The disadvantages of this design are the low resistance of printed circuit boards to mechanical loads arising in a direction parallel to the plane of the base of the electronic unit, and increased weight and dimensions, as well as the complexity of manufacturing associated with the removal of external connectors into a separate cavity.

Along with this, the electronic unit is also known according to US Pat. RF 2367124, N05K 1/00, N05K 7/10, N05K 7/12 , which implements the modular principle of construction using board-to-board connectors. The disadvantages of such a unit are the increased number of fasteners for fixing each module, the presence of an unnecessary base part and the low resistance of printed circuit boards to mechanical loads arising in a direction parallel to the plane of the base of the electronic unit.

In each of the presented analogs, frame structures are used as housing elements to create individual electronic modules.

Known electronic unit according to US Pat. RF 174943 N05K9 / 00 , which includes a body, an upper cover and a lower cover. the disadvantage of which is low resistance to shock loads and the impossibility of assembling the proposed design into a package of modules for creating complex electronic units.

Along with this, the electronic unit is known according to US Pat. RF 197320 H05K 9/00, H05K 5/02 , containing a power and control board, on which power and control elements are located, and a system board with sensitive analog radio elements located on it; output connectors made on boards; board-to-board connections and mounting module.

The disadvantage of this unit is the impossibility of ensuring the temperature regime for heat-generating electrical radio products (ERI).

The closest analogue in technical essence to the proposed one is the electronic unit according to US Pat. RF 2513121, N05K 7/14 , taken as a prototype.

A diagram of the prototype device is shown in Fig. 1a and 1b, where it is indicated:

1 - metal frame;

6 - base;

10 - cover;

11 - bushing;

12 - detachable connector;

13 - additional detachable connector;

14 - a covering protrusion;

15 - male ledge;

16 - printed circuit board;

17 - additional sleeve;

18 - bar;

19 - screws;

20 - fork;

21 - socket.

The prototype device contains at least one metal frame 1, on which the printed circuit assembly 16 is located, assembled together with the cover 10 and base 6 into a package with screws, bushings 11 and detachable connectors 12 and 13.

The prototype device is assembled as follows.

Each metal frame 1 (Fig.1a) is made with female 14 and male 15 stepped protrusions (Fig.1b), on which the printed unit 16 is fixed by means of bushings 11, while the height of the female 14 protrusion is less than the height of the male 15. 6, at the points of attachment to the support (not shown in Fig. 1), holes are made in which additional bushings 17 are installed coaxially with the bushings. The bushings 17 are shaped like two cylinders with different diameters of the threaded hole. The screws are fixed in bushings 17. The detachable connector 12 is fixed directly to the frame 1 by means of a strip 18 and screws 19. The detachable connector 12 consists of a plug 20 and a socket 21. An additional detachable connector 13 is installed on the cover 10.

The disadvantages of this prototype are:

- uniform thickness of the walls of the frames, leading to an increase in weight and dimensions when placing the equipment on thermostatically controlled surfaces;

- the presence of significant displacements of the printed circuit assembly under the influence of mechanical shock loads that can cause opening or deformation of the connectors;

- high parameters of the structure mass, due to the use of redundant screw connection of modules into the electronic equipment unit;

- small thickness of modules without the possibility of placing external leads from printed circuit boards located in the central parts of the block.

- horizontal placement of composite printed circuit assemblies, which worsens the temperature regime for electronic components as they move away from the base.

The task of the proposed device is to increase the mechanical strength of the printed circuit assembly while simplifying the layout of the radio-electronic unit and ensuring high-quality heat removal for the placed electronic devices.

To solve this problem, in the frame of the printed circuit assembly, consisting of at least one metal frame with detachable connectors, as well as a screen and a base, connected in a package, with a printed circuit assembly fixed in each frame, according to the utility model , each frame is equipped with one heat sink side intersecting in the center with longitudinal and transverse stiffeners, as well as an additional stiffener passing along the perimeter of the frame, while at the junction of the screen and the frame, as well as on the longitudinal and transverse stiffeners, there are attachment points formed in the form of a thickening of the material and intended for additional fixation of the printed circuit assembly, in addition, in the corners of the frame and in the middle of each side of the frame there are through holes intended for constructive conjugation of several printed circuit assemblies; in the heat-dissipating side of at least one frame, two fastening holes of the electronic equipment unit are provided for mounting the printed circuit assembly on the surface of the on-board thermoregulation system.

FIG. 2, 3, 4 show a diagram of the general view of the PCB frame and its fragments with the following designations:

1 - metal frame;

2 - through holes;

3 - attachment points;

4 - longitudinal stiffener;

5 - additional points of attachment of the printed circuit assembly;

6 - heat sink side;

7 - transverse stiffening rib;

8 - additional stiffener;

9 - mounting hole of the radio electronic equipment unit;

10 - screen (cover).

The proposed frame of the printed circuit assembly is a rectangular metal frame 1 with one heat sink side 6, longitudinal 4 and transverse 7 stiffening ribs, as well as with an additional stiffening rib 8 passing along the perimeter of the frame 1.

The proposed device is assembled as follows.

A rectangular metal frame 1 around the perimeter encloses the printed circuit assembly (not shown in Fig. 2), while the rigidity of the frame 1 is provided by the longitudinal 4 and transverse 7 stiffeners, as well as an additional stiffening rib 8 passing along the perimeter of the frame 1. Screen 10 of the frame 1, located parallel to the installed printed circuit assembly (Fig. 3c), is a dull surface. At the junction of the screen 10 and the frame 1, there are attachment points 3, formed in the form of a thickening of the material and intended for additional fixation of the printed circuit assembly.

On the longitudinal 4 and transverse 7 stiffeners at a distance of 0.5 of its own length, thickenings of the material of a cylindrical shape are created with the location of additional attachment points 5 used to fasten the printed circuit assembly (printed circuit board) in the frame 1.

In the corners of the frame 1 and in the middle of each lateral side of the frame 1 there are through holes 2 intended for constructive conjugation of several printed circuit assemblies (Fig. 2. and Fig. 3a). Studs are inserted into the through holes 2, which will form an electronic unit from the data set of frames.

The mounting hole of the radio electronic equipment unit on the frame of the printed circuit assembly 9 is used to secure the assembled printed circuit assembly or the electronic unit as part of the onboard equipment of a vehicle or spacecraft. To ensure that the heat-removing side 6 is pressed against the surface of the on-board thermoregulation system, a fastening hole 9 is provided, since the heat-removing side 6 of the frame 1 serves as a heat sink for the heat-generating ERIs as part of the printed circuit assembly.

The design of the PCB frame assumes the width of the side surfaces of the metal frame sufficient to accommodate external detachable connectors, for example, type PC (detachable connector) (GOST 23589-79. Installation of electrical electronic equipment and devices. Technical requirements for the installation of PC and MR connectors).

The frame can be made in one of the following ways: casting followed by machining, from forging followed by machining, milling from a solid plate or metal printing on a 3-d printer. The material for the execution of the PCB frame can be: aluminum structural alloys (АЛ9, Д16, В95, etc.); magnesium structural alloys (MA15, MA18, MA20, MA22, etc.); structural steels (45, 40X, 30HGSA, etc.), high-strength titanium alloys (VT6S, VT14, VT20, VT22, etc.).

Consider the procedure for manufacturing a printed circuit assembly based on a printed circuit assembly and a printed circuit assembly frame:

1. Placing the PCB frame on a flat surface of the installer's desktop.

2. Installation of the printed circuit board on an additional stiffening rib 8 and longitudinal 4 and transverse 7 ribs along the inner side of the perimeter of the metal frame 1 (Fig. 2).

3. Fixing the printed circuit board at the attachment points 3 and 5 (Fig. 3).

4. Installation of ERI, located with heat sinks on the heat sink side 6 of the metal frame 1 or the sides of the frame 1 (Fig. 2 a, b).

5. Soldering the ERI leads and external connectors into a printed circuit board, which becomes a printed circuit assembly.

Thus, in comparison with the prototype, the proposed device provides a reduction in the probability of deformation for a fixed printed circuit assembly under mechanical stress.

The proposed constructive solution changes the PCB mounting scheme and provides resistance to longitudinal shocks up to 1400g, with a pulse duration of 0.3 ms. In addition, unlike the prototype, the proposed frame of the printed circuit assembly provides a greater uniformity of distribution of heat fluxes due to the presence of a heat-removing side 6, used to install heat-loaded elements and a shielding surface 10, which also provides uniform heat removal from the electronic components located at a distance from the heat-removing side.

Claims (1)

The frame of the printed circuit assembly, consisting of at least one metal frame with detachable connectors, connected in a package, as well as a screen and a base, while a printed circuit assembly is fixed in each frame, characterized in that each frame is equipped with one heat sink side intersecting in the center longitudinal and transverse stiffeners, as well as an additional stiffener running along the perimeter of the frame, while at the junction of the screen and the frame, as well as on the longitudinal and transverse stiffeners, there are attachment points formed in the form of a thickening of the material and intended for additional fixation of the printed circuit assembly in addition, in the corners of the frame and in the middle of each side of the frame there are through holes intended for constructive conjugation of several printed circuit assemblies; in the heat-dissipating side of at least one frame, there are two fastening holes for the electronic equipment unit for mounting the printed circuit assembly on the surface of the on-board thermoregulation system.

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