Mounting frame for attaching a conductor board to a housing

Description

Technical area

[0001] The invention relates to a holding frame for attaching a printed circuit board to a housing, in particular within a housing. Furthermore, the invention relates to a corresponding fastening system for a printed circuit board, which comprises such a holding frame and a housing. The invention is particularly directed to the type of fastening of the holding frame to the housing. State of the art

[0002] Printed circuit boards, also known as electronic boards (PCBs, especially electronic control units), can be screwed to a metal housing or attached to a plastic housing using snap-in hooks. Attachment using snap-in hooks is also referred to as a snap connection or clip-in connection. It is also known to attach printed circuit boards to a housing using a plastic carrier with snap-in hooks.

[0003] For example, EP 2 814 309 A2 discloses a holding frame for a printed circuit board, which can be made of plastic, for example. The known holding frame comprises a support structure with support shoulders and locking hooks, between which the printed circuit board is held in a form-fitting manner. Furthermore, this holding frame can comprise a resilient locking element with a locking hook, which is designed to engage resiliently in an opening of a housing, so that the holding frame can be plugged into the housing in a locking manner.

[0004] "CH 649 884 A5 discloses a fastening element for electronic printed circuit boards. DE 10 2008 043 457 A1 discloses a board support assembly for holding a circuit board with a touch sensor. US 5 174 780 A discloses an inclined socket for memory modules." Disclosure of the invention

[0005] According to the invention, a holding frame for attaching a printed circuit board to a housing according to claim 1 and a fastening system according to claim 10.

[0006] Further embodiments are specified in the dependent claims. All further features and effects specified in the claims and the description for the support frame also apply to the fastening system, and vice versa.

[0007] According to a first aspect, a holding frame for attaching a printed circuit board to a housing is provided, the holding frame comprising: a support structure for the printed circuit board; at least one press-in projection that is elastically and / or plastically deformable such that it can be pressed into a recess in the housing with an oversize in order to fasten the holding frame to the housing; and at least one spring element that resiliently connects the at least one press-in projection to the support structure.

[0008] In this case, it can be provided that the circuit board can be merely supported by the support structure of the holding frame or can be attached to it, or both. A press-in projection can be pressed into the corresponding recess in the housing in a press-in direction, for example, to size or to a stop. In addition to a single press-in projection, two, three, or more press-in projections distributed across the holding frame can be provided, each of which is connected to a spring element, which in turn is connected to the support structure.

[0009] Firstly, by providing press-in projections for attaching the retaining frame to the housing, the assembly of the retaining frame on the housing can be made significantly easier. This is due to additional tolerance compensation options compared to fastening with fasteners such as screws or locking hooks, which generally have significantly higher precision requirements for the geometries of the elements to be connected than with a press fit. Secondly, the formation of press-in projections can be easier than with locking hooks because the production of undercuts on the retaining frame and the housing is eliminated. This allows demolding in one direction, particularly when manufacturing the retaining frame by molding, with a single mold half, thus preventing, for example, unwanted demolding flash.

[0010] In particular, the spring elements can ensure that the support structure is connected to the housing in a resilient manner after the press-in projections have been pressed into the housing. This can provide a shock- or vibration-damping mounting of the circuit board to the housing.

[0011] Overall, the above combination of at least one press-in projection with at least one spring element can therefore significantly simplify the assembly or manufacture of the holding frame and / or a housing to which a printed circuit board is to be attached by means of the holding frame. At the same time, however, high mechanical safety requirements for the attachment of the printed circuit board to the housing can be ensured.

[0012] The housing may be a metal housing, in particular a cast housing. However, it may also be made at least partially of another material, such as plastic.

[0013] The support frame can be made entirely or partially of plastic, in particular by injection molding. The spring elements and / or the press-in projections can be formed integrally with the support structure. They can be made of the same or a different material as the support structure and, for example, be molded onto it or connected to it in another manner known to those skilled in the art. By selecting the materials and the geometric design, the deformability of the press-in projections and the spring action of the spring elements can be specifically adjusted.

[0014] For example, it can be provided that at least one of the spring elements is resilient, in particular movable, in a press-in direction of the press-in projection connected to the spring element. Alternatively or additionally, at least one of the spring elements can be resilient, in particular movable, in at least one direction transverse to the press-in direction of the press-in projection connected to the spring element. Depending on the mutual arrangement of the holding frame, the circuit board and the housing, a spring effect in a specific direction can attract the support structure and thus the circuit board, for example, towards the housing in order to hold the circuit board to the housing. Furthermore, mobility of the spring elements in a specific direction can enable additional tolerance compensation between the holding frame, the housing and the circuit board in this direction.Suspension in any other direction can also contribute to a shock and vibration dampening effect of the support frame.

[0015] According to the invention, at least one of the spring elements is designed as a bending arm, which is firmly connected to the support structure at one end and at whose other free end one of the press-in projections is arranged. Such a bending arm represents a bending spring, whereby a specific spring effect can be achieved in its main bending direction and, if necessary, also laterally therefrom in a simple and space-saving manner. The corresponding spring forces can be adjusted, for example, by design parameters of the bending arms, such as length, width, bending path, or relative position with respect to the support structure.

[0016] For example, if the press-in direction of the press-in projection corresponds to the main bending direction of the bending arm, a spring effect is created in the press-in direction. With a narrow, elongated design of the bending arm, a certain spring effect and mobility of the bending arm can also be provided in a lateral direction perpendicular to its main bending direction. The bending arm can, in particular, be essentially straight, particularly web-shaped or leaf spring-shaped. (Here and below, "essentially" is understood to mean, in particular, a possible manufacturing- or design-related deviation of up to approximately 10% from the relevant dimensions.)

[0017] The described spring effects, in particular the lateral mobility, can be achieved, for example, with a bending arm length that is a multiple, in particular at least three, five, or seven times, of each average cross-sectional dimension of the bending arm. The average value is calculated along a longitudinal direction of the bending arm.

[0018] According to the invention, the surface area of ​​the support structure in two spatial directions is many times, in particular at least three, five, or seven times, greater than its height in a third spatial direction perpendicular thereto, for example, to support a flat printed circuit board. According to the invention, two bending arms extend in two different directions away from the support structure in the direction of its surface area. This enables a particularly uniform distribution of the fastening and spring forces across the support structure surface, so that the desired stability and / or spring effect can be achieved with a minimal number of spring elements and press-in projections.

[0019] According to an advantageous further development, two bending arms extend in two substantially opposite directions away from the support structure in the direction of its surface extension.

[0020] In principle, the press-in projections can have any geometric configuration that allows for oversized pressing into a recess in the housing. In particular, at least one of the press-in projections can have one or more laterally projecting deformation elements, such as press ribs or lugs, that are elastically and / or plastically deformable.

[0021] In specific embodiments in which the circuit board can be attached to the support structure, the support structure can have at least one circuit board fastening projection that is elastically and / or plastically deformable such that it can be pressed into a recess in the circuit board with an oversize fit. In particular, at least one of the circuit board fastening projections can have one or more laterally projecting deformation elements, such as pressing ribs or noses, that are elastically and / or plastically deformable. Furthermore, the statements made with regard to the press-in projections can also apply analogously here.

[0022] According to another aspect, a fastening system for a printed circuit board is provided, comprising: a holding frame of a type described herein, and a housing having at least one recess, in particular an elongated groove, for receiving the at least one press-in projection of the holding frame. A dimension of the at least one press-in projection corresponds to an interference fit relative to a dimension of the at least one recess, so that the at least one press-in projection can be pressed into the at least one recess with interference.

[0023] In order to enable additional tolerance compensation between the housing, the holding frame and the printed circuit board, at least one of the recesses in the housing can have a variability extension in at least one variability direction such that one of the press-in projections can be pressed into this recess at several different press-in positions along the variability extension of the recess.

[0024] Such a variability direction can, for example, correspond to the press-in direction of the press-in projection into the recess, so that the press-in depth and thus, in particular, the distance between the retaining frame and the housing can be selected differently. Alternatively or additionally, a variability direction can be transverse to the press-in direction for lateral tolerance compensation, which can be achieved, for example, by means of an elongated groove in the housing. Brief description of the drawings

[0025] Embodiments are explained in more detail below using the example shown in the attached drawings. The drawings are purely schematic and, in particular, are not to be read as being to scale. They show: Figure 1 shows a holding frame and a printed circuit board to be attached to a housing; and Figure 2 shows a housing with the printed circuit board mounted therein by means of the holding frame. Fig. 1 attached circuit board of the Fig. 1 . Description of an embodiment

[0026] Figure 1 shows a schematic, exploded perspective view of a printed circuit board 1 and a support frame 2 for attaching the printed circuit board 1 to a housing. In this example, the support frame 2 is formed in one piece from plastic, for example, by injection molding.

[0027] The support frame 2 has a support structure 3 for the printed circuit board 1, which comprises a plurality of interconnected webs and struts lying approximately in one plane for supporting the flat printed circuit board 1. Accordingly, the surface area of ​​the support structure 3 in a drawn xy plane is many times greater than its height in a z-direction perpendicular thereto.

[0028] The holding frame 2 has two press-in projections 4a and 4b for its attachment to the housing, each of which is resiliently connected to the support structure 3 by a spring element 5a and 5b, respectively. The spring elements 5a and 5b represent bending arms in the form of narrow, straight webs that extend approximately in the y-direction in two opposite directions away from the support structure 3. The press-in projections 4a and 4b are arranged at the respective free ends of the spring elements 5a and 5b and extend, purely by way of example, approximately in the z-direction, which can correspond to their press-in direction.

[0029] Each spring element 5a and 5b, purely by way of example, has an approximately rectangular xz cross-section whose width in the x-direction is approximately or more than twice as large as its thickness in the z-direction, resulting in a main bending direction of the bending arm in the z-direction. When the spring element 5a or 5b is bent in the z-direction, a spring effect is created in the z- and y-directions. Due to their narrow, elongated design, the spring elements 5a and 5b are also resilient and movable in the x-direction. Thus, the spring elements 5a and 5b can resiliently deflect in all directions and thus contribute to the aforementioned shock and vibration damping of the circuit board 1 in the housing.

[0030] Figure 2 shows schematically a perspective top view of a housing 6 in which the printed circuit board 1 from Fig. 1 by means of the holding frame 2 Fig. 1 is attached. In this example, the housing 6 is a cast metal housing, for example aluminum.

[0031] The holding frame 2 is attached to the housing 6 by the two press-in projections 4a and 4b, which are pressed with an oversize into corresponding recesses 7a and 7b in the housing 6. Purely by way of example, the press-in projections 4a and 4b represent approximately cylindrical domes. They have deformation elements not shown in detail in the figures, for example, thickenings compared to a regular cylindrical shape due to laterally projecting press lugs or press ribs, which were elastically and / or plastically deformed when pressed into the recesses 7a and 7b.

[0032] In this example, the recesses 7a and 7b in the housing 6 are formed as elongated grooves extending in the y-direction. Along this variable extension of the recess 7a or 7b, the press-in projection 4a or 4b can be pressed into various positions. This enables tolerance compensation between the circuit board 1, the holding frame 2, and the housing 6 in the y-direction. The above-mentioned lateral mobility of the spring elements 5a and 5b additionally ensures tolerance compensation between the circuit board 1, the holding frame 2, and the housing 6 in the x-direction.

[0033] Furthermore, the press-in positions of the press-in projections 4a and 4b along the recess 7a and 7b can be selected such that the spring elements 5a and 5b are bent and thus prestressed in order to attract the circuit board 1 against the housing 6.

[0034] To secure the printed circuit board 1 to the support structure 3 of the holding frame 2, the support structure 3 in this example additionally has three printed circuit board fastening projections 8a, 8b, and 8c in the form of approximately cylindrical domes with laterally projecting deformation elements in the form of press ribs on the dome tips 9a, 9b, and 9c, as can be seen in the figures. The printed circuit board 1 has recesses 10a, 10b, and 10c in the form of through-holes at corresponding positions, into which the dome tips 9a, 9b, and 9c are pressed when the printed circuit board is pressed onto the support structure 3.

[0035] Furthermore, electronic components for the circuit board 1, such as capacitors 11a and 11b, can be attached in the support structure 3.

Claims

1. Holding frame (2) for attaching a printed circuit board (1) to a housing (6), comprising: • a carrier structure (3) for the printed circuit board (1); • at least one press-in projection (4a, 4b), which is elastically and / or plastically deformable so as to be pressable with an oversize into a cutout (7a, 7b) in the housing (6) in order to fasten the holding frame (2) to the housing (6); and • at least one spring element (5a, 5b), which resiliently connects the at least one press-in projection (4a, 4b) to the carrier structure (3), wherein • at least one of the spring elements (5a, 5b) is formed as a bending arm which, at one end, is connected permanently to the carrier structure (3) and, on the free, other end of which, one of the press-in projections (4a, 4b) is arranged; characterized in that • an areal extent of the carrier structure (3) in two spatial directions (x, y) is a number of times greater than the height extent thereof in a third spatial direction (z) perpendicular thereto; and in that • two of the spring elements formed as bending arms extend in two different directions away from the carrier structure (3) in a direction (y) of its areal extent.

2. Holding frame (2) according to Claim 1, wherein • at least one of the spring elements (5a, 5b) is configured to be resilient, in particular movable, in a direction of pressing-in (z) of the press-in projection (4a, 4b) connected to the spring element (5a, 5b), and / or • at least one of the spring elements (5a, 5b) is configured to be resilient, in particular movable, in at least one direction (x) which is transverse to the direction of pressing-in (z) of the press-in projection (4a, 4b) connected to the spring element (5a, 5b).

3. Holding frame (2) according to Claim 1, wherein the bending arm is of substantially straight, in particular web-like, form.

4. Holding frame (2) according to Claim 1 or 3, wherein a bending-arm length is a number of times, in particular at least three, five or seven times, an average cross-sectional dimension of the bending arm in this case.

5. Holding frame (2) according to one of Claims 1 to 4, wherein • two bending arms extend in two substantially opposite directions away from the carrier structure (3) in a direction (y) of its areal extent.

6. Holding frame (2) according to one of the preceding claims, wherein at least one of the press-in projections (4a, 4b) has one or more laterally projecting deformation elements, in particular pressing ribs or pressing noses, which are elastically and / or plastically deformable, whereby the press-in projection (4a, 4b) is pressable with an oversize into a cutout (7a, 7b) in the housing (6).

7. Holding frame (2) according to one of the preceding claims, wherein the carrier structure (3) has at least one printed-circuit-board fastening projection (8a, 8b, 8c) which is elastically and / or plastically deformable so as to be pressable with an oversize into a cutout (10a, 10b, 10c) in the printed circuit board (1) in order to fasten the printed circuit board (1) to the carrier structure (3).

8. Holding frame (2) according to Claim 7, wherein at least one of the printed-circuit-board fastening projections (8a, 8b, 8c) has one or more laterally projecting deformation elements, in particular pressing ribs or pressing noses, which are elastically and / or plastically deformable, whereby the printed-circuit-board fastening projection (8a, 8b, 8c) is pressable with an oversize into a cutout (10a, 10b, 10c) in the printed circuit board (1).

9. Holding frame (2) according to one of the preceding claims, which holding frame is produced at least partially from plastic, in particular by injection moulding.

10. Fastening system for a printed circuit board (1), comprising: • a holding frame (2) according to one of the preceding claims; and • a housing (6), which has at least one cutout (7a, 7b), in particular an elongated groove, for receiving the at least one press-in projection (4a, 4b) of the holding frame (2); • wherein a dimension of the at least one press-in projection (4a, 4b) in comparison with a dimension of the at least one cutout (7a, 7b) corresponds to an interference fit, so that the at least one press-in projection (4a, 4b) is pressable with an oversize into the at least one cutout (7a, 7b).

11. Fastening system according to Claim 10, wherein at least one of the cutouts (7a, 7b) in the housing (6) has in at least one direction of variability (y) a variability extent such that one of the press-in projections (4a, 4b) is pressable into this cutout (7a, 7b) at multiple different press-in positions along the variability extent of the cutout (7a, 7b).

12. Fastening system according to Claim 11, wherein the at least one direction of variability (y) corresponds to a direction of pressing-in of the press-in projection (4a, 4b) into the cutout (7a, 7b) and / or to a direction (y) which is transverse, in particular substantially perpendicular, thereto.