Heat generating element with connection structure

Abstract

A heat generating element includes at least one PTC element, contact sheets flatly lying against the PTC element on either side, a housing which forms at least one opening for receiving the at least one PTC element and which has a terminal side at which contact tongues allocated to the contact sheets are exposed. The device also has a wedge element with a broader and a narrower end face which are connected to each other via first and second wedge surfaces, the first wedge surface extending in parallel to one of the contact sheets and lying against it with a slide plate being inserted, and the second wedge surface being exposed at the outer side of the housing. A heat generating element less susceptible to damages during assembly has a slide plate connected to the housing.

Claims

1. A heat generating element comprising: a PTC element, a first contact sheet flatly lying against the PTC element on a first side thereof, a second contact sheet flatly lying against the PTC element on a second side thereof, a housing which forms an opening for receiving the PTC element and which has a terminal side at which contact tongues allocated to the contact sheets are exposed, and a wedge element with a broader end face and a narrower end face which are connected to each other via first and second wedge surfaces, the first wedge surface extending in parallel to one of the contact sheets and lying against the one contact sheet with a slide plate being inserted therebetween, the slide plate having opposing spring arms, and the second wedge surface being exposed at the outer side of the housing, wherein a portion of the slide plate is connected with a securing opening of the housing so that the slide plate is held in a non-slidable manner that prevents a relative movement between the slide plate and the housing, and wherein the wedge element is held between the opposing spring arms and the portion of the slide plate.

2. The heat generating element according to claim 1, wherein the slide plate is connected to the housing with a form-fit.

3. The heat generating element according to claim 1, wherein the portion of the slide plate is a securing bracket which is received in the securing opening formed through the housing.

4. The heat generating element according to claim 3, wherein the securing opening is allocated to the narrower end face of the wedge element.

5. The heat generating element according to claim 1, wherein the slide plate is connected with the housing at opposite end regions of the housing.

6. The heat generating element according to claim 1, wherein, through the slide plate, the wedge element is secured to the housing.

7. The heat generating element according to claim 1, wherein the contact sheets are secured to the housing after formation thereof.

8. The heat generating element according to claim 1, wherein at least one of the contact sheets has a bent-over tongue received in an insertion opening of the housing.

9. The heat generating element according to claim 8, wherein at least one latching projection which is latched with the housing projects from a surface of the tongue oriented essentially at right angles to a locating surface for the PTC element.

10. A heat generating element comprising: a PTC element, a first contact sheet flatly lying against the PTC element on a first side thereof and a second contact sheet flatly lying against the PTC element on a second side thereof, a housing which forms an opening for receiving the PTC element, which forms a latching projection, and which has a terminal side at which contact tongues allocated to the contact sheets are exposed, and a wedge element with a broader end face and a narrower end face which are connected to each other via first and second wedge surfaces, the first wedge surface extending in parallel to one of the contact sheets and lying against the one contact sheet with a slide plate being inserted therebetween, the slide plate having opposing spring arms, and the second wedge surface being exposed at the outer side of the housing, wherein the slide plate is connected to the housing with a form-fit at an end thereof allocated to the broader end face of the wedge element by a latching connection which has at least one resilient latching web formed by the slide plate and received by the latching projection, wherein the slide plate is provided with a securing bracket received within a securing opening of the housing so that the slide plate is held in a non-slidable manner that prevents a relative movement between the slide plate and the housing, and wherein the wedge element is held between the opposing spring arms and the latching connection provided by the slide plate.

11. The heat generating element according to claim 10, wherein the latching web protrudes over a front end of a sliding surface allocated to the wedge element and supporting it flatly.

12. The heat generating element according to claim 10, wherein the latching projection is centrically disposed at the housing and integrally formed to the housing.

13. The heat generating element according to claim 10, wherein the latching web grips over the wedge element.

14. A heat generating element comprising: a PTC element, a first contact sheet flatly lying against the PTC element on a first side thereof, a second contact sheet flatly lying against the PTC element on a second side thereof, a housing which forms an opening for receiving the PTC element and which has a terminal side at which contact tongues allocated to the contact sheets are exposed, and a wedge element with a broader end face and a narrower end face which are connected to each other via first and second wedge surfaces, the first wedge surface extending in parallel to one of the contact sheets and lying against the one contact sheet with a slide plate being inserted therebetween, the slide plate having opposing spring arms, and the second wedge surface being exposed at the outer side of the housing, wherein a securing bracket of the slide plate is inserted into a securing opening of the housing so as to hold the slide plate in a non-slidable manner that prevents a relative movement between the slide plate and the housing, and wherein the wedge element is held between the opposing spring arms and the securing bracket of the slide plate.

15. The heat generating element according to claim 14, wherein the slide plate is connected to the housing with a form-fit.

16. The heat generating element according to claim 14, wherein the securing opening is allocated to the narrower end face of the wedge element.

17. The heat generating element according to claim 14, wherein the slide plate is connected with the housing at opposite end regions of the housing.

18. The heat generating element according to claim 14, wherein, through the slide plate, the wedge element is secured to the housing.

19. The heat generating element according to claim 14, wherein the contact sheets are secured to the housing after formation thereof.

20. The heat generating element according to claim 14, wherein at least one of the contact sheets has a bent-over tongue received in an insertion opening of the housing.

21. The heat generating element according to claim 20, wherein at least one latching projection which is latched with the housing projects from a surface of the tongue oriented essentially at right angles to a locating surface for the PTC element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details and advantages of the present invention can be taken from the following description of an embodiment in connection with the drawing. In the drawings:

(2) FIG. 1 shows a perspective plan view onto the embodiment from a first upper side;

(3) FIG. 2 shows a perspective plan view onto the embodiment from a second upper side;

(4) FIG. 3 shows a perspective view similar to FIG. 2 while the slide plate is being connected;

(5) FIG. 4 shows a perspective plan view similar to FIG. 2 after the final assembly of the embodiment;

(6) FIG. 5 shows a longitudinal section along the central longitudinal axis of the completely mounted embodiment shown in FIG. 4, and

(7) FIG. 6 shows a longitudinal section along a line extending in parallel to the central longitudinal axis which intersects the tongue of a contact sheet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(8) FIG. 1 shows a housing of one embodiment designated with reference numeral 2 while this housing 2 is being connected with a first contact sheet 4. The housing 2 forms an opening 6 over the inner periphery of which spacer elements 8 protrude which are integrally formed at the housing 2 and have an essentially pyramidal shape, where the surfaces of the spacer elements 8 extending between a plane edge 10 of the opening 6 formed by the housing 2 and the tip of the spacer element 8 are of a concave shape. These spacer elements 8 are used for placing PTC elements against them which are designated with reference numeral 12 in FIG. 2. The spacer elements 8 retain the PTC elements 12 at a distance to the edge 10 and accordingly enlarge the leakage current path.

(9) In a side view, the housing 2 has an essentially wedge-shaped design with a front narrow end 14 and a broader end which forms a terminal side 16 of the housing 2. The opening 6 is defined by lateral faces 18 which are provided on either side of the opening 6 and extend in parallel to each other. These lateral faces 18 completely surrounding the opening 6 are surrounded, in the longitudinal direction of the housing 2 and at the front end 14, by a slightly broadened external edge 20 which protrudes over the lateral faces 18 on both sides and has a wedge-shaped design in the longitudinal direction of the housing 2, i.e. it has a smaller width at the front end 14 than at the terminal side 16. At the terminal side 16, the housing 2 furthermore forms a surrounding and broadened collar 22 which externally protrudes over the contour of the outer edge 20 at the terminal side 16 and forms a support surface 24 by which the housing 2 installed in a pocket of an electric heating device is supported at its upper side on a heater housing of the electric heating device, as is known from EP 1 921 896 A1.

(10) At the front end 14, the lateral face 18 provided there and extending transversely to the longitudinal extension of the housing 2 is penetrated by two insertion openings 26, 28. The insertion opening seen in the front in FIG. 1 and designated with reference numeral 26 serves to fix the contact sheet 4 shown in FIG. 1. For this, the latter includes a tongue 30 which protrudes over a front lateral face 32 of the contact sheet 4 and is formed by punching and bending. The tongue 30 accordingly has a smaller width than the contact sheet 4 in the region of the front lateral face 32 which protrudes slightly over the tongue 30 to the front—as seen in FIG. 1—and considerably to the rear. The tongue 30 is bent by 90° with respect to a locating surface 34 for the PTC elements 12 formed by the contact sheet 4 and protrudes inwards over this locating surface 34. The tongue 30 has an externally directed latching surface 36 extending at right angles to the locating surface 34 and over which two latching projections 38 protrude. The latching projections 38 are formed by punching the sheet material forming the contact sheet 4 and protrude over the latching surface 36 as convexly shaped latching noses.

(11) The insertion opening 26 passes over, via a convexly curved mouth section 40, into the opening 6 which serves for locating a curved transitional region 42 between the locating surface 34 and the tongue 30. The mouth section 40 is located lower than the lateral face 18, so that in an installed condition, the contact sheet 4 is disposed flush with respect to the lateral face 18.

(12) A contact lug 46 protrudes over a rear lateral face 44 of the contact sheet 4 at its end opposed to the tongue 30, which is, just like the insertion lug, provided with an essentially smaller width compared to the allocated lateral face 44 by punching it free and protrudes over it. At its free end, the contact lug 46 forms a contact tongue 48 via which the electrical connection to the contact sheet 4 is accomplished and which projects over the housing 2 at the terminal side 16. Between this contact tongue 48 and the locating surface 34 of the contact sheet 4, it forms a locating projection 50 which is provided by cutting out a step in the contact lug 46. For receiving a longitudinal region of the contact lug 46, the lateral face 18 is interrupted by a mounting 52 the base of which extends in parallel to the lateral face 18 and forms a locating surface for the contact lug 46. The edge 10 of the housing 2 that laterally defines the mounting 52 forms a locating shoulder 54 which is allocated to the locating projection 50 such that the latter abuts against it when the contact tongue 48 is inserted into a through hole 56 recessed at the housing 2, thus stopping the introduction motion. In this position, the locating projection 50 abuts against the locating shoulder 54 like a swivel joint. By a swiveling motion about this point, the tongue 30 is necessarily swiveled into the insertion opening 26 and fixed therein with a form-fit by cooperation of the latching projections 38 with a locking projection 58 formed on the housing side (cf. FIG. 6).

(13) As can be in particular seen in FIG. 6, the through hole 56 is formed by an obliquely oriented lead-through channel 60. This oblique lead-through channel 60 is formed by a flattening 62 oriented towards the center—in the width direction—and to the outside, which extends from the lateral face 18 and a flattening 64, which extends in parallel thereto and is provided opposite to it, and which is formed at a wall of the collar 22 internally defining the through hole 56. For forming the lead-through channel 60, only the flattening 64 might be provided and the oblique surface 62 omitted.

(14) In the width direction of the embodiment, the oblique lead-through channel 60 correspondingly extends from the lateral face 18 to the outside towards the terminal side 16 towards the center in the width direction. By this, the introduction of the contact lug 46 through the through hole 56 is facilitated when the contact sheet 4 is oriented obliquely to the lateral face 18. The walls limiting the through hole 56 furthermore lead to an orientation of the contact sheet 4 with its longitudinal edges 66 in parallel to the allocated edges 20 of the housing 2, so that the contact sheet 4 is already oriented, after the contact lug 46 has been inserted into the through hole 56, such that the tongue 30 is flush with the insertion opening 26.

(15) After the contact sheet 4 has been connected with the housing 2 in the above described manner, in the course of the assembly, the housing 2 is rotated, so that the side shown at the top in FIG. 1 is at the bottom. This position is illustrated in FIG. 2. Now, several, in the present case four, PTC elements 12 are introduced into the opening 6 closed at the bottom side by the contact sheet 4, and they are placed onto the locating surface 34 of the contact sheet 4. Then, a further contact sheet 68 formed essentially identically to the contact sheet 4 is oriented at the housing 2 in the manner described above with reference to FIG. 1 and latched with the latter. The contact sheet 68 is essentially identical to the contact sheet 4, the difference being that spring tongues 70 formed by punching and bending are formed facing the individual PTC elements 12 for improving electric contacting, the spring tongues 70 protruding over a plane locating surface 72 of the contact sheet 68.

(16) As is illustrated in FIGS. 1 and 2, between the latching surface 18 and the outer edge 20, a U-shaped groove 74 is recessed. This groove 74 surrounds the contact sheet 4 and 68, respectively, mounted in the manner described above in a U-shape and serves to receive a sealing compound 76 which is introduced into the groove 74. This sealing compound 76 can have sticky properties and serves the sealing and optionally also fixing of an insulation layer designated with reference numeral 78 to the outer side of the contact sheet 4 and 68, respectively. This insulation layer 78 in the present case has a two-layer structure with a silicone film and a glass fiber mat connected to it. Such an insulation layer 78 exhibits high electric strength and can be manufactured with an exact thickness as an essentially incompressible insulation layer 78.

(17) After the insulation layer 78 has been applied onto the lateral faces 18, the contact sheets 4 and 68, respectively, are insulated against the surrounding area. Then, a slide plate designated with reference numeral 80 is placed onto the in FIG. 2 upper side. At its end allocated to the front end 14 of the housing 2, this slide plate 80 has two securing brackets 82 which are each separately formed essentially identical to the tongues 30, the difference being that only one latching projection 38 protrudes over each of the securing brackets 82. Corresponding to the two securing brackets 82 provided in the width direction one next to the other, securing openings 84 are recessed at the housing 2. The slide plate 80 is introduced with its securing brackets 82 into the allocated securing openings 84 in the manner described above with reference to the contact sheet 4 and connected with the housing 2 with a form-fit. As is illustrated in FIG. 6, the securing openings 84 are slightly broadened upwards, so that the slide plate 80 can be swiveled about the pivot formed between the securing opening 84 and the securing bracket 82 within limits. After the securing brackets 82 have been introduced into the securing openings 84, the slide plate 80 assumes the position shown in FIG. 3. Then, the slide plate 80 is placed against the housing 2 with its whole surface.

(18) At its front end 86 facing the terminal side 16, the slide plate 80 comprises a latching web 88 which is formed by punching and bending the sheet material forming the slide plate 80, and a sliding surface 90 formed by the slide plate 80, and it has a hook-like design, so that the latching web 88 forms a first section 92 extending essentially at right angles to the sliding surface 90 and a second section 94 also extending at right angles thereto and in parallel to the sliding surface 90 to the inside. For increasing the flexural strength of the latching web 88, the latter is penetrated by a bead 96 formed by bending and extending in the longitudinal direction of the housing 2, the bead being bent to the outside. The second section 94 has a free end broadening like a funnel towards the outside.

(19) By punching and bending, flanks 98 are formed in the upper third of the slide plate 80, i.e. in the region allocated to the terminal side 16, the flanks limiting the sliding surface 90 at the edge but in the mounted state not protruding over the lateral faces 18 to a greater extent than the wedge-shaped outer edges 20 at the level of the corresponding flanks 98. At the terminal side, the flanks 98 pass over into spring arms 10 which are cut free with respect to the sliding surface 90 and bent to the inside.

(20) On the side shown in FIGS. 2 to 4, the collar 22 is provided with two large through holes 102 between which a support web 104 is integrally formed at the housing 2 which forms an internally projecting latching projection 106 at its free end. The latching projection 106 lies within an enveloping surface around the collar 22.

(21) When the slide plate 80 is swiveled from the preliminary orientation shown in FIG. 3 to the final position shown in FIGS. 4 to 6, the latching web 88 is urged to the inside by the latching projection 106 and springs back when the final position of the slide plate 80 is reached, so that the slide plate 80 is also retained to the housing 2 with a form-fit at the terminal side 16.

(22) Now, a wedge element designated with reference numeral 108 is placed onto this slide plate 80 connected in this manner with the housing 2 at opposite end regions (cf. FIGS. 4 to 6). The wedge element 108 has a broader end face designated with reference numeral 110 which is allocated to the terminal side 16, and a narrower end face designated with reference numeral 112 which is allocated to the front end 14. The wedge element 108 has such a width that the wedge element 108 is non-positively held between the spring arms 100. In the starting position shown in FIG. 4, the wedge element 108 is furthermore gripped over by the second section 94 of the latching web 88 and correspondingly held between this section 94 and the sliding surface 90 in a form-fit. In this starting position, a first wedge surface designated in FIG. 6 with reference numeral 114 is in parallel to the sliding surface 90 which in turn extends in parallel to the contact sheet 68, whereas a second wedge surface designated with reference numeral 116 is exposed at the outer side of the housing 2. In the starting position shown in FIG. 6, this second wedge surface 116 is still slightly underneath the contour given by the outer edge 20. By shifting from the right to the left (according to FIG. 6) and due to the wedge-shaped design of the wedge element 108 with an angle of about 3°, the wedge element 108 finally protrudes over this contour and accordingly interlocks the embodiment of a heat generating element 120 illustrated in FIGS. 4 to 6 in a conical pocket of an electric heating device. On the side opposite the wedge element 108, the insulation layer 78 is exposed at the housing 2 and is approximately flush with the contour of the edge 20 provided at this side. Usually, the insulation layer 78 slightly protrudes over this edge.

(23) As illustrates in particular FIG. 5, the front free end of the second section 94 of the latching web 88 is still within the support surface 24, so that the positioning of the heat generating element 120 at the heater housing is not affected by the mounting of the wedge element 108. The insertion of the wedge element is done by introducing two tool projections through the through hole 102. The wedge element 108 has a cavity at its broadened end 110, so that the corresponding tools are well positioned at the wedge element 108.