Control Device and Electric Heating Device Comprising the Same

Abstract

A control device and electric heating device having such a control device are disclosed. The control device has a control housing which surrounds a printed circuit board, which has a partition wall provided with a cooling element, and which accommodates at least one power switch that makes contact with the printed circuit board and that is applied in a heat-conducting manner against the cooling element via a hold-down device. The power switch and the hold-down device are realized in a pre-assembled module connected to the cooling element.

Claims

1. A control device for an electric heating device, the control device comprising: a printed circuit board; a control housing which surrounds the printed circuit board, which has a partition wall provided with a cooling element, and which accommodates at least one power switch that makes contact with the printed circuit board and that is applied in a heat-conducting manner against the cooling element via a hold-down device, wherein the power switch and the hold-down device are realized in a pre-assembled module connected to the cooling element.

2. The control device according to claim 1, wherein the module comprises a spring device which is provided between the hold-down device and the power switch and by which the power switch is applied under pretension against the cooling element.

3. The control device according to claim 2, wherein the spring device is held on the hold-down device via a form-fit connection acting at least transversely to a direction of action of its spring force.

4. The control device according to claim 2, wherein the spring device is formed by a silicone component.

5. The control device according to claim 4, wherein the silicone component comprises a hollow silicone body.

6. The control device according to claim 2, wherein the power switch is movably held in the module while varying a pretension is imposed by the spring device.

7. The control device according to claim 1, wherein the module comprises a positioning frame forming at least one accommodation for a respective power switch.

8. The control device according to claim 7, wherein the positioning frame and the hold-down device are clipped together with the power switch and the spring device.

9. The control device according to claim 7, wherein the positioning frame comprises an opening surrounding the cooling element and bounded by a support for the power switch.

10. The control device according to claim 7, wherein the positioning frame forms a window that is penetrated by at least one contact pin of the power switch and that is bounded at a top thereof by the hold-down device.

11. An electric heating device comprising: a control device that includes a printed circuit board, and a control housing which surrounds the printed circuit board, which has a partition wall provided with a cooling element, and which accommodates at least one power switch that makes contact with the printed circuit board and that is applied in a heat-conducting manner against the cooling element via a hold-down device, wherein the power switch and the hold-down device are realized in a pre-assembled module connected to the cooling element; a heater housing including a heating chamber, wherein the partition wall is provided between the control housing and the heater housing; and at least one PTC heating assembly that protrudes from the partition wall as a heating fin into the heating chamber, wherein the PTC heating assembly has at least one PTC element and contact tongues which are electrically conductively connected to the PTC element with different polarity in order to energize the PTC element and which are electrically connected in the control housing; wherein a heat sink to the cooling element is exposed in the heating chamber.

12. The electric heating device according to claim 11, wherein the module comprises a spring device which is provided between the hold-down device and the power switch and by which the power switch is applied under pretension against the cooling element.

13. The electric heating device according to claim 11, wherein the module comprises a positioning frame forming at least one accommodation for a respective power switch.

14. The electric heating device according to claim 13, wherein the positioning frame and the hold-down device are clipped together with the power switch and the spring device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] This previously mentioned electric heating device has a control device according to one of the preceding claims.

[0030] Further details and advantages of the present invention will be apparent from the following description in conjunction with the drawing. Therein:

[0031] FIG. 1 shows a perspective exploded view of an embodiment of an electric heating device;

[0032] FIG. 2 shows a longitudinal sectional view of a PTC heating assembly of the heating device according to FIG. 1;

[0033] FIG. 3 shows a perspective side view of a module above the printed circuit board and the cooling element;

[0034] FIG. 4 shows a longitudinal sectional view of a module after assembly;

[0035] FIG. 5 shows a cross-sectional view of the module according to FIG. 3;

[0036] FIG. 6 shows a perspective side view of an alignment element before assembly;

[0037] FIG. 7 shows a perspective side view of an alignment element after assembly;

[0038] FIG. 8 shows an enlarged detail of FIG. 5;

[0039] FIG. 9 shows a top view of the illustration according to FIG. 8.

DETAILED DESCRIPTION

[0040] FIG. 1 shows an embodiment of an electric heating device 2 with a multi-part heater housing 3 comprising a housing lower part 4 formed of plastic and a housing upper part 6 integrally formed of metal by die casting.

[0041] The housing lower part 4 is trough-shaped, encloses a heating chamber 8 and forms openings to inlet and outlet ports 10 which communicate with the heating chamber 8. These inlet and outlet ports 10 are integrally formed with the housing lower part 4 by injection molding. A plurality of PTC heating assemblies 12 are shown between the housing upper part 6 and the housing lower part 4.

[0042] As illustrated in FIG. 2, these PTC heating assemblies 12 each have at least one PTC element 14 against which conductor elements 15 in form contact sheets 16 abut, which form contact tongues 18 that extend beyond a metal housing 20. The PTC element 14 is accommodated in a frame 22 and between the contact sheets 16. Between each of the metallic housing 20 and the contact sheets 16 an insulating layer 24 is provided.

[0043] The PTC heating assemblies 12 are held in plug-in contact in accommodations 26 provided for this purpose in a partition wall 28 of the housing upper part 6. Details of this configuration are described in EP 3 334 242 A1 and counterpart U.S. Pat. No. 10,724,763, which originates from the applicant and the subject matter of which are hereby incorporated by reference.

[0044] On the side of the partition wall 28 opposite the PTC heating assemblies 12, a connection chamber 30 is formed, which is surrounded by a control housing 32 comprising a control housing cover 34, which is connected to the housing upper part 6 in a sealed manner via a seal 36. A first printed circuit board 38 is located in the connection chamber 30, which accommodates the contact tongues 18 and groups the individual PTC heating assemblies 12 into heating circuits

[0045] In the control housing 32, a second printed circuit board characterized by reference sign 40 is provided, which is equipped with electronic components not shown in detail. Reference sign 42 characterizes a module shown in more detail in further FIG. 3 et seq. which is part of the control device characterized by reference sign 44 in FIG. 1.

[0046] Next to the module 42, FIG. 3 schematically shows the partition wall 28 from which a cooling element 46 projects in the direction of the connection chamber 30. This cooling element 46 forms a flat cooling surface 48. The cooling elements 46 are extended into the heating chamber 8 and form heat sinks 49 there. In extension of the cooling surface 48 and adjacent thereto, the housing upper part 6 also forms form-fit segments 50 on the side of the cooling element, which also protrude as slightly conical projections from the partition wall 28 presently schematically shown flatly.

[0047] The module 42 includes a hold-down device 52 that is formed as an elongated plastic component and forms form-fit mating segments 54 at its respective ends, which can positively cooperate with the form-fit segments 50 to position the hold-down device 52 relative to the housing upper part 6 and thus the control housing 32.

[0048] With reference sign 56, a positioning frame is characterized that forms a plurality of accommodations 58 for power switches 60. Each power switch 60 has three contact pins, characterized by reference sign 62, that are bent about 90 degrees approximately centrally and have a contact-side section 64 that extends substantially perpendicular to the major extension of the printed circuit board 40.

[0049] As FIG. 4 conveys, the hold-down device 52 has lateral detents 66 that encompass the positioning frame 56 on the underside. The side of the module 42 facing the printed circuit board 40 is referred to as the underside. Corresponding to these detents 66, the positioning frame 56 has ramp surfaces 68 on its upper side against which the detents 66 slide in the course of assembly when the hold-down device 52 is clipped to the positioning frame 56.

[0050] As can be seen from FIGS. 4 and 5, the accommodations 58 are substantially adapted to the dimensions of the power switches 60. On the underside, the positioning frame 56 forms an opening 70 in which the power switches 60 are each exposed. The opening 70 is bounded by a web 72 projecting toward the opening 70, which forms a support 74 for the power switch 60. FIGS. 4 and 5 furthermore show a spring device configured as a silicone spring 76 in the form of a hollow body. The silicone spring 76 is configured as a short piece of tubing and is pushed onto a pin 78 formed by the hold-down device 52, resulting in a form-fit connection between the silicone spring 76 and the hold-down device 52, via which the silicone spring 76 is fixed at right angles to its spring force relative to the hold-down device 52.

[0051] In the course of assembly, the individual components are first provided. Then the silicone spring 76 can be pushed onto the respective pins 78 in order to provide the hold-down device 52 with the spring devices. In parallel, the individual power switches 60 are inserted into the accommodations 58 assigned to them. For this purpose, the positioning frame 56 has a window, characterized by reference sign 80 in FIG. 5, which allows the power switch 60 to be lowered into the accommodation 58 without impairing the alignment of the contact pins 62. After the respective power switches 60 have been assembled, they rest on the support 74. The hold-down device 52 is then approached to the positioning frame 56. In the process, the detents 66 slide past the ramp surfaces 68. The detents 66 are spread and spring back on the underside of the positioning frame 56, forming a form-fit connection between the hold-down device 52 and the positioning frame 56. As part of this joining motion, the silicone springs 76 are accommodated between the hold-down device 52 and the power switches 60, slightly pretensioned if necessary. The module 42 thus produced is then assembled in the control housing 32. For this purpose, the module 42 is approached to the housing upper part 6. In the process, the cooling element 46 penetrates the opening 70 and is applied against the power switches 60 in a heat-conducting manner. An insulating layer, for example in the form of a polyimide film or a ceramic layer, is usually inserted beforehand between the cooling surface 48 and the power switches 60 to prevent direct electrical contact between the power switch 60 and the cooling element 46. The joining motion may be guided by the interaction of the form-fit segments 50 with the form-fit mating segments 54. This may result in pre-positioning of the module 42 relative to the cooling element 46.

[0052] Subsequently, screws characterized by reference sign 82 are screwed into the housing upper part 6. These have the effect of fixing the hold-down device 52 to the housing upper part 6 and thus compressing the silicone springs 76 and accordingly applying the power switches 60 under pretension. Obviously, the opening is appropriately dimensioned so that the cooling element 46 can easily immerse into the positioning frame 56. Cross beams 84 of the positioning frame 56, which bound the individual accommodations 58 in the longitudinal direction of the hold-down device 52 and separate the respective accommodations 58 from one another, allow a corresponding movement. These cross beams 84 are reduced in height compared to the longitudinal beams 86 drawn in FIG. 5.

[0053] FIGS. 6 to 9 illustrate an alignment element of a plastic material characterized by reference sign 90 in FIG. 5. This serves to facilitate insertion of the contact-side section 64 of the contact pin into the printed circuit board 40. The alignment element 90 has a passage 92 which is aligned with a plug-in slot 94 for the respective contact pin 62 within the printed circuit board 40. The plug-in slot 94 is created by a connecting piece 96 which is electrically contacted with at least one strip conductor of the printed circuit board 40 and which is shown in FIGS. 6 and 8. The details of this connection are described in EP 2 236 330 A1 and counterpart U.S. Pat. No. 8,803,036, both of which are incorporated by reference. This connecting piece 96 lies basically flatly on the upper side of the printed circuit board 40. Only upwardly curved radii 98 of retaining webs which engage in bores of the printed circuit board 40 project slightly beyond the otherwise flat surface of the connecting pieces 96.

[0054] As can be seen in particular from FIGS. 8 and 9, the alignment element 90 has a significantly widened opening 100 around the passage 92 on the side facing away from the printed circuit board 40 compared to the dimensions of the passage 92. This opening 100 merges into the passage 92 without a shoulder via inwardly inclined ramp surfaces 102. The alignment element 90 is mounted on the printed circuit board 40 such that the passage 92 is precisely aligned with the plug-in slot 94 within the printed circuit board 40. For this purpose, the alignment element 90 comprises positioning pins 104 that extend through a positioning bore 106 within the printed circuit board 40 and project beyond the printed circuit board 40 on the underside. The positioning pins 104 extend from a protrusion that forms a contact surface 108, which is provided annularly around the positioning pin 104. The alignment element 90 is applied against the printed circuit board 40 via the contact surfaces 108. As can be seen from FIGS. 6 and 7, two positioning pins 104 and corresponding positioning bores are provided for each alignment element 90. Through this interaction, elements of a form-fit connection 107 are already provided by which the alignment element 90 is held transversely to the printed circuit board 40 in a form-fit manner and is fastened in this sense.

[0055] As can be seen in particular from FIGS. 6, 7, and 8, the alignment element 90 further has a latching leg 110 that forms a latching surface 112 abutting against the underside of the printed circuit board 40. This latching leg 110 also clips against the printed circuit board 40. The latching leg 110 is tethered by two connecting webs 114 that abut against the front surface of the printed circuit board 40 with a certain transverse spacing. By this configuration, the printed circuit board is encompassed at the edge by the alignment element 90.

[0056] As FIG. 5 illustrates, the free ends of the positioning pins 104 abut against the partition wall 28. In this way, the alignment element 90 is supported locally in the area of the passage 92, which mechanically relieves the printed circuit board 40 when the contact pins 62 are inserted.

[0057] As can be seen from FIG. 6, the alignment element 90 shown there has a plurality of passages 92 with corresponding openings 100 and ramp surfaces 102. The comparison of this illustration with FIG. 3 conveys that a single alignment element 90 is provided for each power switch 60. Thus, the number of passages 92 per alignment element 90 corresponds to the number of contact pins 62 of the power switch 60. FIG. 3 conveys four alignment elements 90 connected in series side by side with the printed circuit board 40.

[0058] In the course of assembling the module 42, the individual contact pins 62 with their contact-side sections 64 are aligned with the plug-in slots 94 via the respective ramp surfaces 102 of the corresponding alignment elements 90. Any misalignment is usually compensated for by the elasticity of the contact pins 62.