ELECTRIC HEATING DEVICE

Abstract

The invention relates to a device (10) for electrically heating a fluid, said device comprising: - a body (12) comprising at least one fluid circulation chamber (14) and an opening (16), - a heating element (20) configured to be introduced into the chamber (14) in an axial direction (A), the heating element being provided with a heating portion (22) arranged in the fluid circulation chamber (14) and a closure element (24) configured to close the opening (16) of the body (12), - a sealing member (30) interposed between the body (12) and the closure element (24), said sealing member (30) being configured to be compressed between a first portion (32) of said closure element (24) and a bearing surface (34) of said body (12), one and / or the other of the first portion (32) and the bearing surface (34) being smooth. Figure for abstract: Figure 1.

Description

Title of the invention: ELECTRIC HEATING DEVICE Technical field of the invention

[0001] The invention relates to a device for electrically heating a fluid, in particular an electric heating device intended for a motor vehicle. Technical background

[0002] Electric fluid heating devices are used in the automotive industry to heat a fluid. In this sense, electric fluid heating devices are known comprising a body delimiting a circulation chamber for the fluid to be heated. Said body comprises an opening through which a heating element allowing the heating of this fluid is introduced into the body. The fluid is in particular a heat transfer fluid, such as a mixture of water and glycol.

[0003] To ensure the sealing of the circulation chamber, the opening is closed by a closing element. A sealing member is interposed between the closing element and the body.

[0004] The closure element is introduced axially into the opening, so that a portion of this closure element is arranged opposite an internal bearing surface of the body. The sealing member is interposed between this portion of the closure element and the internal bearing surface of the body.

[0005] Conventionally, the sealing member is produced in the form of a simple seal which is received in one or more grooves which are formed in the portion of the closure element and the bearing surface of the body facing each other.

[0006] In either case, the installation of such a seal therefore requires the creation of a groove to hold it in place. The creation of such a groove involves, on the one hand, machining in the closure element and in the bearing surface, which is in itself a costly operation. On the other hand, the creation of such a groove requires, when it is made in the closure element, having a closure element of sufficient thickness to be able to carry out this machining, which also increases the manufacturing cost of such a device, because it involves having a solid closure element obtained by casting or forging.

[0007] There is therefore a real need for a heating device making it possible to achieve a reliable seal between the closure element and the bearing surface, at reduced cost. Summary of the invention

[0008] The invention meets this need by proposing an electric heating device

[0009]

[0010]

[0011]

[0012]

[0013]

[0014] making it possible to improve the insulation between the sealing element and the body, while maintaining satisfactory sealing. For this purpose, the invention proposes a device for electrically heating a fluid, said device comprising: - a body comprising at least one fluid circulation chamber, and an opening, - a heating element configured to be introduced into the chamber, the heating element having a heating portion disposed in the fluid circulation chamber and a sealing element configured to seal the opening of the body, - a sealing member interposed between the body and the closure element, said sealing member being configured to be compressed between a first portion of said closure element and a bearing surface of said body, one and / or the other of the first portion and the bearing surface being smooth. It will be understood that by "smooth" we mean a surface without protrusions and / or without a groove. The use of parts having smooth surfaces, namely parts without protrusions and / or grooves, opposite the sealing members allows their cost to be reduced. In addition, a good seal is maintained by choosing to use a sealing member configured to be compressed between such smooth surfaces of the body and / or the closure element. According to various additional characteristics of the invention, which may be taken together or separately and which form as many embodiments of the invention: - the opening opens into a support face of said body, - the heating element is configured to be introduced through the opening into the chamber in an axial direction, - the sealing element is stamped, - the device is configured to limit an axial displacement of said sealing member between shoulders formed respectively on said body and said closure element, - said body and said closure element are kept at a distance from each other on the chamber side by a clearance, - said play is a transverse play, in particular radial, - the first portion extends substantially axially, - the bearing surface extends substantially axially so that the radial clearance separates, along the axial direction, the first portion of the sealing element and the bearing surface, - the sealing member comprises a single-body seal, - the joint comprises at least two protrusions spaced axially from one another the other, forming sealing barriers, the joint comprises three or four protrusions spaced axially from each other, the joint, the bearing surface and the first portion are parts of revolution in the axial direction, the seal is annular, the growths extend radially, each protrusion extends towards the bearing surface and / or towards the first portion of the closure element, the seal comprises an annular portion extending axially in contact with one of the first portion and the bearing surface, the protrusions are shaped as lips extending to the other of the first portion and the bearing surface, each protrusion has an apex which is in contact with said bearing surface and / or said first portion of the closure element, each protrusion comprises a first apex and a second opposite apex, the first apex being in contact with the first portion of the closure element and the second apex being in contact with the bearing surface of the body, the seal comprises an annular portion extending axially and at least two, in particular four, lobes extending from the annular portion both towards the bearing surface and towards the first portion of the closure element,the seal extends over at least 80%, in particular over at least 90% of the axial length of the first portion and over at least 80%, in particular at least 90% of the axial length of the bearing surface, the maximum thickness of the seal, before it is placed in the body, is greater than the clearance between the bearing surface and the first portion, the maximum thickness of the seal corresponds to the thickness of a lobe, the annular portion of the seal has a thickness less than the clearance between the bearing surface and the first portion, to allow the protrusions to deform when the seal is compressed, the sealing member comprises a first and a second seal adjacent to each other, , the first portion of the closure element is inserted inside the body, the bearing surface is arranged around the first portion of the closure element, the closure element carries the heating portion of the heating element, the opening is crossed by at least two electrical terminals of the element heating. the first portion of the closure element is tubular, for example cylindrical, in particular in the form of a right circular cylinder, the bearing surface is cylindrical, in particular in the form of a right circular cylinder, the seal is arranged around the first portion of the closure element, the body and the closure element are made of two different metallic materials, the body is made of an aluminum alloy and / or the closure element is made of stainless steel, the sealing member is electrically insulating, the opening is provided in a support face of said body, the body comprises a counterbore, extending the opening towards the chamber, into which the seal(s) and the first portion of the sealing element are inserted, the body comprises a first shoulder face against which the or one of the seals is likely to bear axially, the counterbore is delimited, on the chamber side, by the first shoulder face, the first shoulder face is turned towards the bearing face of the body, the counterbore comprises, at its junction with the bearing face of the body, a chamfer capable of allowing the seal to be inserted into the groove, the closure element comprises at a first end of the first portion, a second portion which borders the first portion and which is shaped as a collar, the second portion of the sealing element is supported against the support face, the collar forms a second shoulder surface against which the or another of the seals is likely to bear axially, the second portion is fixed to said bearing face, the joint extends over at least 80%, in particular at least 90% of the length of the counterbore, the closing element comprises, at a second end of the first portion, a third portion shaped as a transverse partition which closes the first portion, said third portion carries one or more electric heating members forming the heating portion, said third portion is crossed by at least two connection terminals of the electrical terminals of said electric heating member, - the connection terminals of the heating element protrude from the sealing element, at the opening, on the side opposite the chamber, - the device comprises two parallel circulation chambers formed in the body and each receiving at least one said electric heating element, the circulation chambers opening into the support face of said body, - each chamber communicates with the exterior of the body via a supply channel formed in the body substantially opposite the bearing face, - each chamber communicates with the other chamber of the body via an internal transfer channel formed in the body substantially close to the bearing face. Brief description of the figures

[0015] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the detailed explanatory description which follows, of at least one embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the appended schematic drawings among which:

[0016] [Fig-1] [Fig.l] is an exploded perspective view of a heating device electric according to a first embodiment of the invention;

[0017] [Fig.2] [Fig.2] is a sectional view through plane 2-2 of [Fig.l];

[0018] [Fig.3] [Fig.3] is a detail view of [Fig.2] illustrating the positioning of a seal for the electric heating device according to the first embodiment of the invention;

[0019] [Fig.4] [Fig.4] is a detailed perspective view cut through plane 2-2 of [Fig.l];

[0020] [Fig.5] [Fig.5] is a sectional view through plane 5-5 of [Fig.l];

[0021] [Fig.6] [Fig.6] is a half-sectional view through plane 2-2 of [Fig.l] of the organ sealing, shown mounted in the device.

[0022] [Fig.7] [Fig.7] is a partial, cut-away perspective view of the joint of [Fig.6], in its free state. Detailed description of the invention

[0023] [Fig. 1] shows a device 10 for electrically heating a fluid produced in accordance with the invention. Said fluid is, for example, a heat transfer fluid such as a mixture of water and antifreeze, in particular glycol.

[0024] The device 10 comprises a body 12 which is for example made by molding an aluminum alloy, such as cast aluminum. As illustrated in Figures 1, 2, 4 and 5, the body 12 comprises at least one chamber 14 for circulation of the fluid. A opening 16 of this chamber 14 opens into a support face 18 of the body 12.

[0025] A heating element 20 is configured to be introduced into the chamber 14, preferably through the opening in the chamber 14 in an axial direction A of said chamber 14. As illustrated in [Fig.l], the axial direction A here corresponds to the direction of introduction of the heating element 20 into the body 12.

[0026] The heating element 20 is provided with a heating portion 22 which is arranged in the fluid circulation chamber 14 when it is in place in the chamber 14, and a closure element 24 which is configured to close the opening 16 of the body 12. The body 12 and the closure element 24 are advantageously made of different materials. The closure element 24 is here preferably made of stainless steel. The closure element 24 is preferably stamped.

[0027] In the embodiment, which has been shown here, the device 10 comprises two parallel circulation chambers 14 formed in the body 12, which each receive at least one said electric heating element 20, the two circulation chambers 14 opening into the same bearing face 18 of the body 12.

[0028] As illustrated in Figures 1 and 2, each chamber 14 communicates fluidically with the exterior of the body 12 via a channel 26a, 26b which is formed in the body 12 substantially opposite the bearing face 18. The channels 26a, 26 are respectively a supply channel 26a and an evacuation channel 26b. Furthermore, as illustrated in Figures 1 and 5, each chamber 14 communicates with the other chamber 14 of the body 12 via an internal transfer channel 28 formed in the body 12 substantially close to the bearing face 18. The fluid enters one of the chambers 14 of the device via a supply channel 26a, passes through this chamber 14, passes into the other chamber 14 via the transfer channel 28, passes through the other chamber 14 and exits via the discharge channel 26b.

[0029] To ensure the sealing of each chamber 14, a sealing member 30 is interposed between the body 12 and the closure element 24. According to the invention, this sealing member 30 is configured to be compressed between a first portion 32 of the closure element 24 and a bearing surface 34 of the body 12, one and / or the other of the first portion 32 and the bearing surface 34 being smooth.

[0030] The absence of grooves or protrusions in said body and / or in said closure element makes it possible to reduce the manufacturing costs of the device 10 by limiting the number of machining operations carried out. Furthermore, this arrangement makes it possible to use a closure element 24 which is, as has been seen, preferably stamped, and consequently all the less expensive to manufacture.

[0031] More particularly, the first portion 32 of the closure element 24 is inserted inside the body 12.

[0032] Advantageously, the mounting of the sealing member 30 between the first portion smooth 32 of the closure element 24 and / or the smooth bearing surface 34 of the body 12 makes it possible, unlike a conventional assembly in which the sealing member 30 is received in a groove of the closure element or of the body, to maintain the portion 32 of the closure element 24 of the body with 24 at a distance with a substantial clearance J between the first portion 22 of the closure element 24 and the smooth bearing surface 34 of the body 12, as shown in Figures 3 and 4. As a result, thanks to the clearance J, transverse to the axial direction A, which is introduced between the closure element 24 and the body 12, any contact between the closure element 24 and the body 12 on the side of the chamber 14, that is to say in the part of the body 12 bathed in fluid, and they are kept at a relatively high distance.

[0033] The sealing member 30 is also electrically insulating. The closure element and the body are thus isolated at the level of the circulation chamber 14, which makes it possible to avoid corrosion phenomena due to the formation of electrochemical couples between the body 12 and the closure element 24.

[0034] More particularly, the body 12 comprises for its part a counterbore 36, comprising the bearing surface 34, which extends substantially axially opposite the first portion 32, so that said transverse clearance J separates, along the axial direction, the first portion 32 of the closure element 24 and the bearing surface 34. The bearing surface 34 is therefore arranged around the first portion 32 of the closure element 24. The first portion 32 and the bearing surface 34 are preferably both smooth.

[0035] Without limiting the invention, the first portion 32 of the closure element 24 and the bearing surface 34 are parts of revolution in the axial direction. The first portion 32 of the closure element 24 and the bearing surface 34 are cylindrical, in particular in the form of right circular cylinders. The sealing member 30 is produced, in addition, in the form of a part of revolution in the axial direction, namely a substantially annular or cylindrical seal. The sealing member 30 will therefore be called a seal in the remainder of this description. The transverse clearance J is therefore also a radial clearance.

[0036] Furthermore, the device 10 is configured to limit an axial displacement of the sealing member or seal 30 between shoulders 38, formed respectively on the body 12 and the closure element 24.

[0037] For this purpose, the bearing surface 34 and / or the counterbore 36 extends the opening 16 in the direction of the chamber 14, in which the seal 30 and the first portion 32 of the closure element 24 are inserted. As illustrated in FIGS. 2 and 4, the counterbore 36 is delimited, on the side of the chamber 14, by a first shoulder face 38 which is turned towards the bearing face 18 of the body 12. The seal 30 is capable of bearing axially against this first shoulder face 38 in order to limit the risks of damage. fitting of the seal 30 towards the chamber 14. On the opposite side, the counterbore 36 is delimited by the bearing face 18 of the body 12. The counterbore 36 comprises, at its junction with the bearing face 18 of the body 12, a chamfer 50 which is capable of allowing and / or facilitating the introduction of the seal 30 into the counterbore 36.

[0038] The first portion 32 of the closure element 24 is advantageously tubular, in particular due to the production of the closure element 24 by stamping. The closure element 24 comprises at a first end of the first portion 32, a second portion 40 which borders the first portion 32, and which is shaped as a collar. The second portion 40 is here connected by a radius to said first portion 32. This radius advantageously forms a second shoulder surface for said seal 30, which is capable of bearing axially against this second shoulder surface in order to limit the risks of the seal 30 becoming loose in a space formed in the vicinity of the chamfer 50.

[0039] The second transverse collared portion 40 here bears on the bearing face 18 of the body 12. More particularly, this collar 40 is fixed to the bearing face 18 of the body 12. To ensure its fixing, the second collared portion 40 preferably comprises holes 44 intended to allow the passage of fixing screws 46 which are received from the threads 48 of the body 12.

[0040] At a second end of the first tubular portion 36, the closure element 24 comprises a third portion 42 which is shaped as a transverse partition which closes the first tubular portion 32.

[0041] The opening is crossed by electrical terminals 43 of the heating element 20. For this purpose, the closure element 24 carries the heating portion 22 of the heating element 20. More particularly, the third portion 42 carries one or more electrical heating members forming the heating portion 22. The third portion 42 is crossed by at least two terminals 52 for connecting the electrical terminals 43 of the heating portion 22. In particular, these terminals 52 pass through holes 54 formed in the third portion 42 in a collar, as shown in [Fig.2].

[0042] According to the invention, as illustrated more particularly in [Fig. 6], according to a first embodiment of the sealing member 30, the latter is preferably produced in the form of a single-body seal 30. As a variant (not shown), according to a second embodiment of the sealing member 30, the latter could also be produced in the form of a first and second single-body seals adjacent to each other, or of a plurality of single-body seals juxtaposed axially.

[0043] In the preferred embodiment of the invention, however, the single single-body seal 30 comprises at least two, and in particular three or four, protrusions 56, axially spaced from one another, as shown in [Fig. 6]. Due to the compression of the seal 30, the protrusions 56 are compressed in contact with the first portion 32 and / or of the bearing surface 34. The protrusions 56, axially spaced from one another, form successive sealing barriers which prevent the fluid from escaping from the chamber 14 towards the closure element 24, so that the heat transfer fluid circulating in the chamber 14 in practice never reaches the part of the closure element 24 in contact with the body 12, namely here the collar 40.

[0044] Preferably, the seal 30 comprises three or four protrusions 56 spaced axially from one another. This number is adequate to ensure good sealing. The protrusions 56 extend radially.

[0045] According to one embodiment (not shown) of the protrusions, each protrusion extends either towards the bearing surface 34 or towards the first portion 32 of the closure element 24. In this first embodiment of the protrusions, the seal 30 comprises an annular portion extending axially in contact with one of the first portion 32 and the bearing surface 34 and lip-shaped protrusions extending to the other of the first portion 32 and the bearing surface 34.

[0046] All the protrusions may be in contact with the first portion 32 or all the protrusions may be in contact with the bearing surface 34.

[0047] According to another variant, a first group of protrusions may be in contact with the first portion 32 and a second group of protrusions may be in contact with the bearing surface 34. The protrusions of the first group and of the second group may succeed one another, for example alternately.

[0048] However, according to the preferred embodiment of the protrusions 56 which has been shown in [Fig. 6], each protrusion 56 extends both towards the bearing surface 34 and towards the first portion 62 of the closure element. Each protrusion 56 has a vertex 58 which is in contact with the bearing surface 34 or the first portion 32 of the closure element 24.

[0049] Each protrusion thus comprises a first apex 58a and a second opposite apex 58b, the first apex 58a being in contact with the first portion 32 of the closure element 24 and the second apex 58b being in contact with the bearing surface 34 of the body 12.

[0050] The protrusions 56 can take any shape capable of ensuring good sealing. However, preferably, in this second embodiment of the protrusions 56, the seal 30 here comprises an annular portion 60, shown in dotted lines in [Fig. 6], extending axially and at least two, in particular four lobes 62 extending from the annular portion both towards the bearing surface 34 and towards the first portion 32 of the closure element. In this case, the maximum thickness of the seal 30 corresponds to the thickness of a lobe 62.

[0051] Preferably, the seal 30 extends over at least 80%, in particular over at least 90%. of the axial length of the first portion 32 and over at least 80%, in particular at least 90% of the axial length of the bearing surface 34. The joint also extends over at least 80%, in particular at least 90% of the length of the counterbore 36.

[0052] As seen in [Fig.6], the seal 30, once mounted, is compressed. It will therefore be understood that the maximum thickness of the seal 30, before its installation in the body 12, is greater than the clearance J between the bearing surface 34 and the first portion 32. Similarly, the annular portion 60 of the seal has a thickness E less than J than the clearance between the bearing surface 34 and the first portion 32, to allow the protrusions 58, and therefore the lobes 62, to deform when the seal 30 is compressed.

[0053] [Fig.7] illustrates the joint of [Fig.6], before assembly, in the free state.

Claims

Claims

1. Device (10) for electrically heating a fluid, said device comprising: - a body (12) comprising at least one fluid circulation chamber (14), and an opening (16), - a heating element (20) configured to be introduced into the chamber (14) in an axial direction (A), the heating element being provided with a heating portion (22) arranged in the fluid circulation chamber (14) and a sealing element (24) configured to seal the opening (16) of the body (12), - a sealing member (30) interposed between the body (12) and the sealing element (24), said sealing member (30) being configured to be compressed between a first portion (32) of said sealing element (24) and a bearing surface (34) of said body (12), one and / or the other of the first portion (32) and the surface of bearing (34) being smooth.

2. Heating device (10) according to the preceding claim, wherein said closure element (24) is stamped.

3. Device (10) according to one of the preceding claims, configured to limit an axial displacement of said sealing member (30) between shoulders (38, 40) formed respectively on said body (12) and said closure element (24).

4. Device (10) according to one of the preceding claims, in which said body (12) and said closure element (24) are kept at a distance from each other on the chamber side (14) by a clearance (J).

5. Device (10) according to the preceding claim, in which said clearance (J) is transverse, in particular radial.

6. Device (10) according to one of claims 4 or 5, in which the first portion (32) extends substantially axially, and in which the bearing surface (34) extends substantially axially opposite said first portion (32) so that said radial clearance (J) separates, along the axial direction (A), the first portion (32) of the closure element (24) and the bearing surface (34),

7. 7. Device (10) according to one of the preceding claims, in which said sealing member (30) comprises a single-body seal (10) comprising at least two and in particular three or four protrusions (58), axially spaced from one another.

8.

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10.

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12.

13. 8. Device (10) according to one of claims 1 to 6, wherein said sealing member (30) comprises a first and a second seal adjacent to each other. Device (10) according to one of the preceding claims, in which the sealing member (30) is electrically insulating. Device (10) according to one of the preceding claims, in which the opening (16) is provided in a bearing face (18) of said body, Device (10) according to one of the preceding claims, in which the closure element (24) comprises at a first end of the first portion (32), a second portion (40) which borders the first portion (32), which is shaped as a collar Device according to the preceding claim, in which the second portion (40) of the closure element (24) bears against the bearing face (18).

13. Device (10) according to the preceding claim, in which: - the body (34) comprises a counterbore (36), extending the opening (16) in the direction of the chamber (14), in which the sealing member (30) and the first portion (32) of the closure element (24) are inserted, said counterbore (36) being delimited, on the side of the chamber (14), by a first shoulder face (38) facing the bearing face (18) of the body (14) against which the or one of the seals (30) is capable of bearing axially, - the second portion (40) of the closure element forms a second shoulder surface against which the or another of the seals (30) is capable of bearing axially.

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