Electric Heating Device and Method for Its Production

Abstract

An electric heating device comprises a housing with a partition wall which separates a connection chamber from a heating chamber for dissipating heat and from which at least one PTC heating element with a heater casing protrudes in the direction toward the heating chamber. The at least one PTC element and conductor tracks are supported in the heater casing in an insulated manner. The heater casing is sealed against the partition wall by way of a seal arranged in a receptacle of the partition wall circumferentially surrounding the heater casing. A press ring is arranged in the receptacle and surrounds the heater casing circumferentially, securing the seal in the receptacle. A method of forming such an electric heating device also is disclosed.

Claims

1. An electric heating device comprising: a housing having a partition wall which separates a connection chamber from a heating chamber for dissipating heat and from which at least one PTC heating element with a heater casing protrudes toward the heating chamber; at least one PTC element and conductor tracks that are supported in the heater casing, the conductor tracks being electrically connected to the PTC element in the connection chamber and being configured to energize the PTC element with different polarities, wherein the heater casing is sealed against the partition wall by way of a seal arranged in a receptacle of the partition wall circumferentially surrounding the heater casing; and a press ring that is arranged in the receptacle, that circumferentially surrounds the heater casing, and that secures the seal in the receptacle.

2. The electric heating device according to claim 1, wherein the PTC element and the conductor tracks are received in a shielded manner in the heater casing, and wherein the press ring is electrically conductive and electrically connects the heater casing to a ground terminal of the housing.

3. The electric heating device according to claim 1, wherein the press ring and the seal are realized in a unitary component.

4. The electric heating device according to claim 1, wherein the press ring is arranged between the seal and the heating chamber.

5. The electric heating device according to claim 1, wherein the press ring is secured in the receptacle by press-fit stemming the housing.

6. The electric heating device according to claim 1, wherein the press ring has several contact projections on an outer circumferential surface thereof that extend in a direction of insertion of the receptacle and that abut, at least in part, under plastic deformation in the receptacle.

7. A method for producing an electric heating device, the heating device including a housing having a partition wall which separates a connection chamber from a heating chamber for dissipating heat and from which at least one PTC heating element with a heater casing protrudes toward the heating chamber, at least one PTC element and conductor tracks being supported in the heater casing, the conductor tracks being electrically connected to the PTC element in the connection chamber and being configured to energize the PTC element with different polarities, the method comprising: introducing and the PTC heating device into a receptacle of the partition wall such that the PTC heating device protrudes from the partition wall in a direction toward the heating chamber; and introducing a press ring into the receptacle and securing the press ring in position in the receptacle.

8. The method according to claim 7, further comprising securing the press ring in position by press-fit stemming the housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further details and advantages of the present invention shall become apparent from the following description of an embodiment in combination with the drawing, in which:

[0019] FIG. 1 shows a perspective explosion view of the embodiment of an electric heating device;

[0020] FIG. 2 shows a longitudinal sectional view of the PTC heating device (of the embodiment without a seal;

[0021] FIG. 3 shows a perspective side view of a detail of the electric heating device before the PTC heating device is joined;

[0022] FIG. 4 shows the detail according to FIG. 3 in an enlarged view when the PTC heating device is joined;

[0023] FIG. 5 shows a view according to FIG. 4 at the end of the joining process of the PTC heating device which is still received in the setting tool;

[0024] FIG. 6 shows a view of FIG. 4 or 5 after the joining process of the PTC heating device once the setting tool has been removed;

[0025] FIG. 7 shows a perspective side view of the PTC heating device after the press-fit stemming process; and

[0026] FIG. 8 shows a top view onto the PTC heating device after the press-fit stemming process.

DETAILED DESCRIPTION

[0027] FIG. 1 shows an embodiment of an electric heating device 100 with a multi-part housing which comprises a housing lower part 102 made of plastic material and a housing upper part 104 formed integrally from metal by way of die casting.

[0028] The housing lower part 102 is trough-shaped and surrounds a heating chamber 106, to which inlet and outlet ports 110 projecting from a base 106 are provided.

[0029] Illustrated between the housing upper part 104 and the housing lower part 102 in FIG. 1 is a plurality of PTC heating devices 112 which within a heater casing 111 closed circumferentially and at the underside comprise a PTC element 113 and conductor tracks 115, which are electrically contacted with the PTC element 113, cf. FIG. 2. The conductor tracks 115 are electrically connected by way of contact strips 114. The PTC heating devices 112 are held in a plug-contacted manner in receptacles 116 provided for this purpose in a partition wall 117 of the housing upper part 104. Provided in this receptacle 116 is also a seal 119 which circumferentially surrounds the heater casing 111 and is pressed into the receptacle 116.

[0030] Details of this configuration are described in EP 3 334 242 A1 which originates from the applicant.

[0031] Further elements of the heating device 100 are shown between the housing lower part 102 and the housing upper part 104. A high-voltage plug element is denoted by reference numeral 118 and screwed to the housing lower part 104 and comprises contact elements projecting into a connection chamber 120 of the housing upper part 104. These contact elements are electrically connected to a printed circuit board denoted by reference numeral 12 which can be accommodated in the trough-shaped housing upper part 104. Reference numeral 124 denotes a seal which seals the housing lower part 102 against the housing upper part 104 and therefore the heating chamber 106.

[0032] A contacting device 130 is arranged above the housing upper part 104 and below the printed circuit board 122 and electrically connects all the contact strips 114 and groups individual PTC heating devices 112 to form heating circuits. An electrical connection between the contacting device 130 and the printed circuit board 122 is established by way of contact strips 132 projecting from the contacting device 130. Connected to the circuit board 142 and protruding therefrom is a control signal plug element illustrated by reference numeral 134. This control signal plug element 134 is screwed against the circuit board 122.

[0033] A further circumferential seal 136 and a control housing cover 138 with which the connection chamber 120 of the housing upper part 104 is covered and sealed are shown above the printed circuit board 122. The control housing cover 138 is made of metal in order to shield together with the housing upper part 104 against electromagnetic radiation which arises from the switching the power current within the control housing 104, 136, 138. A support frame 140 is arranged between the control housing cover 138 and the circuit board 122 and supports compression elements 142 between itself and the circuit board 122 in order to, for example, press power transistors mounted on the circuit board 122 against cooling surfaces which are connected in a thermally conductive manner to cooling domes extended into the heating chamber 106. The cooling surfaces are connected to the power transistors in a thermally conductive manner.

[0034] After the assembly, connecting rods 144 engage behind locking projections 145 which are provided on the housing lower part 102 and the housing upper part 104 in order to connect the two parts 102, 104 captively and in a positive-fit manner to one another. Details on this are described in EP 2 796 804 A1.

[0035] The control housing cover 138, together with the housing upper part 104 and the seal 136, forms a control housing 146. Due to their metallic materials, the control housing cover 138 and the housing upper part 104 form a shielding around the control device 148 which is accommodated in this control housing 146 and is substantially formed by the printed circuit board 122. A connecting bolt 150 protrudes from the control housing 146 in the direction of the plug elements 118, 134. This connection pin 150 is used to connect the metallic control housing 146 to a ground phase and is screwed to the control housing 146.

[0036] The assembly of the PTC heating device 112 in the receptacle 116 arises in particular from the following description of FIGS. 3 to 8.

[0037] Where FIG. 3 shows a side view in an exploded illustration with the housing upper part 102, the partition wall 117 of which forms a plurality of receptacles 116 into which the PTC heating devices 112 are to be inserted. One of the PTC heating devices 112 is shown in FIG. 3 flush with a setting tool 200. The PTC heating device 112 evidently bears the seal 119 which is already mounted on the heater casing 111.

[0038] As can be seen from FIG. 4, the PTC heating device 112 is first inserted into the associated receptacle 116. The seal 119 is there pressed into the receptacle. Already this results in sufficient sealing of the PTC heating device 112 in the associated receptacle 116.

[0039] The setting tool 200 bears a press ring 202 at its front end. This press ring 202 is arranged at the front end of the chamber-shaped setting tool 200. The chamber of the setting tool 200 is configured such that it can basically completely accommodate the heating device 112 (cf. FIG. 5). A holder, not shown in detail, of the setting tool for releasably attaching the press ring 202 is provided with deformation projections 204 directly adjacent to the press ring 202 and in a direction opposite to the direction of insertion marked with E. When the setting tool 200 is slipped over the PTC heating device 112 together with the press ring 202, the press ring 202 is pushed, firstly, into the receptacle 116 and pressed in at the same time. Contact projections 206 provided on the press ring 202, extending in the direction of insertion E and protruding beyond the otherwise smooth outer circumferential surface of the press ring 202 claw into the inner wall of the receptacle 116. In the present case, the press ring 202 is made entirely of metal. It is in electrical contact with the housing upper part 102 due to the direct contact with the inner circumferential surface of the receptacle 116. However, it is also in contact with the outer circumferential surface of the heater casing 111 even after having been pressed into the receptacle 116. Electrical contact is established between the heater housing 111 and the upper housing part 102 by pressing in the press ring 202. The heater casing 111 is accordingly electrically integrated into the shielding of the housing upper part.

[0040] During the insertion motion of the setting tool 200, the deformation projections 204 are pressed against the front edge of the receptacle 116, which leads to a plastic deformation of the edges of the receptacle 116. As a result of this press-fit stemming, the material initially extending exclusively in the direction of insertion E and defining the receptacle 116 is also deformed radially inwardly and in the direction toward the heater casing 111. After the press-fit stemming process, parts of the partition wall 117 engage over the press ring 202 which is thereby secured in the receptacle 116 in a positive-fit manner.

[0041] The respective deformation regions are identified in FIGS. 7 and 8 as press-fit stemming deformations 208. The press-fit stemming deformation 208 is deformed in the direction of insertion E downwardly and also radially inwardly relative to the free edge of the receptacle 116, the edge being identified by reference numeral 210. As can be seen, adjacent receptacles 116 can share a common wall (cf. FIG. 6) so that several previously inserted press rings 202 are secured in a positive-fit manner in the associated receptacle 116 as described above when the edge 210 is press-fit stemmed.