Exhaust gas heat exchanger with latching contours

Abstract

An exhaust gas heat exchanger may include a housing and a heat exchanger block arranged therein, the heat exchanger block including tube plates and a tube bundle having a plurality of flat tubes held at longitudinal ends of the flat tubes in rim holes formed in a complementary manner thereto in the tube plates. A first flow path for exhaust gas may extend in the flat tubes, and a second flow path for coolant may extend around the flat tubes and within the housing. The housing may include a plurality of latching contours, which interact with a plurality of counterpart latching contours arranged on an associated tube plate to fix the tube plates and the heat exchanger block on the housing.

Claims

1. An exhaust gas heat exchanger comprising: a housing and a heat exchanger block arranged therein, the heat exchanger block including tube plates and a tube bundle having a plurality of flat tubes held at longitudinal ends of the flat tubes in rim holes formed in a complementary manner thereto in the tube plates; wherein a first flow path for exhaust gas extends in the plurality of flat tubes and a second flow path for coolant extends around the plurality of flat tubes and within the housing; wherein a plurality of latching contours in the form of latching hooks are provided on the housing, the plurality of latching contours interacting with a plurality of counterpart latching contours each in the form of a rim along an external edge of an outer surface of an associated tube plate in which the rim holes are formed, each latching contour extending linearly from the housing to a distal end of the latching contour in a direction of the tubes to latch to the external edge in a direction transverse to the direction of the tubes such that the plurality of latching contours stops the associated tube plate from moving laterally and longitudinally to fix the tube plates and the heat exchanger block on the housing; and wherein at least one of the latching hooks includes a plurality of legs extending from the housing in the direction of the tubes and being spaced apart from each other, and a cross member at a distal end of the hook connecting the plurality of legs, the cross member including a latch portion that projects from the plurality of legs in a direction transverse to the direction of the tubes at the distal end of the hook to latch to the external edge via the latch portion.

2. The exhaust gas heat exchanger according to claim 1, wherein the housing and the tube plates are formed from metal.

3. The exhaust gas heat exchanger according to claim 1, wherein the housing and the tube plates are at least one of soldered and welded together.

4. The exhaust gas heat exchanger according to claim 3, wherein the housing and the tube plates are formed from metal.

5. The exhaust gas heat exchanger according to claim 1, wherein the plurality of latching contours are arranged at least partially circumferentially at a rim of the housing such that the associated tube plate is clamped in place in between.

6. The exhaust gas heat exchanger according to claim 5, wherein the housing and the tube plates are at least one of soldered and welded together.

7. The exhaust gas heat exchanger according to claim 1, wherein the plurality of latching contours are formed in one piece with the housing.

8. The exhaust gas heat exchanger according to claim 7, wherein the housing and the tube plates are at least one of soldered and welded together.

9. A method for producing an exhaust gas heat exchanger, comprising: providing a housing having a plurality of latching contours in the form of latching hooks, a plurality of flat tubes and a first tube plate and a second tube plate, the first tube plate and the second tube plate each having a plurality of rim holes and a plurality of counterpart latching contours each in the form of a rim along an external edge of an outer surface of an associated tube plate in which the rim holes are formed, the plurality of counterpart latching contours arranged to interact with the plurality of latching contours of the housing, each latching contour extending linearly from the housing to a distal end of the latching contour; fixing the first tube plate on one side of the housing via the plurality of latching contours and the plurality of counterpart latching contours of the first tube plate by latching a corresponding latching hook to the external edge of the first tube plate; introducing the plurality of flat tubes into the plurality of rim holes in the first tube plate and positioning the plurality of flat tubes in the housing; placing the second tube plate on an opposite side of the housing such that the plurality of flat tubes pass into the plurality of rim holes in the second tube plate; pressing the second tube plate onto the housing until the plurality of latching contours latch together with the plurality of counterpart latching contours of the second tube plate and fix the second tube plate on the housing by latching a corresponding latching hook to the external edge of the second tube plate; and at least one of soldering and welding the first tube plate and the second tube plate to the housing; wherein at least one of the latching hooks includes a plurality of legs extending from the housing in the direction of the tubes and being spaced apart from each other, and a cross member at a distal end of the hook connecting the plurality of legs, the cross member including a latch portion that projects from the plurality of legs in a direction transverse to the direction of the tubes at the distal end of the hook to latch to the external edge via the latch portion.

10. The method according to claim 9, wherein the housing and the tube plates are formed from metal.

11. The method according to claim 9, wherein the plurality of latching contours are arranged at least partially circumferentially at the rim of the housing such that the associated tube plate is clamped in place in between.

12. The method according to claim 9, wherein the plurality of latching contours are formed in one piece with the housing.

13. An exhaust gas heat exchanger comprising: a housing formed from metal having a plurality of latching contours in the form of latching hooks arranged at least partially circumferentially at a rim of the housing, each latching contour extending linearly from the housing to a distal end of the latching contour; a heat exchanger block having a plurality of flat tubes; and at least two tube plates formed from metal, each of the at least two tube plates having a plurality of rim holes and a plurality of counterpart latching contours each in the form of a rim along an external edge of an outer surface of an associated tube plate in which the rim holes are formed, the external edge being arranged to receive a corresponding latching hook thereon to fix the at least two tube plates and thus the heat exchanger block to the housing; wherein the plurality of flat tubes are held at their longitudinal ends by the plurality of rim holes in the at least two tube plates; wherein a first flow path for exhaust gas extends in the plurality of flat tubes and a second flow path for coolant extends around the plurality of flat tubes and within the housing; and wherein at least one of the latching hooks includes a plurality of legs extending from the housing in the direction of the tubes and being spaced apart from each other, and a cross member at a distal end of the hook connecting the plurality of legs, the cross member including a latch portion that projects from the plurality of legs in a direction transverse to the direction of the tubes at the distal end of the hook to latch to the external edge via the latch portion.

14. The exhaust gas heat exchanger according to claim 13, wherein the housing and the at least two tube plates are at least one of soldered and welded together.

15. The exhaust gas heat exchanger according to claim 13, wherein the plurality of latching contours are formed in one piece with the housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings, in each case schematically,

(2) FIG. 1 shows a side view of an exhaust gas heat exchanger according to the invention,

(3) FIG. 2 shows a front view of the exhaust gas heat exchanger according to the invention with a tube plate,

(4) FIG. 3 shows a sectional illustration through a latched connection between the housing and tube plate of the exhaust gas heat exchanger.

DETAILED DESCRIPTION

(5) According to FIGS. 1 to 3, an exhaust gas heat exchanger 1 according to the invention, which can be used for example in the region of an internal combustion engine 2 of a motor vehicle, has a housing 3 with a heat exchanger block 4 arranged therein. The heat exchanger block 4 has a tube bundle having a plurality of flat tubes 5 which are held at their longitudinal ends in rim holes 6, formed in a complementary manner thereto, in tube plates 7, 8. In this case, a first flow path for exhaust gas extends in the flat tubes 5 themselves, while a second flow path for coolant extends in a known manner around the flat tubes 5 and within the housing 3. According to the invention, in order to fix the tube plates 7 on the housing 3, latched connections are now provided, specifically latching contours 9 which interact with counterpart latching contours 10 arranged on an associated tube plate 7, 8 and thus fix the two tube plates 7, 8 and the heat exchanger block 4 on the housing 3.

(6) On viewing the latching contours 9 according to FIGS. 1 to 3, it is possible to see that they are formed, in a particularly simply designed case, as latching lugs 11, while the counterpart latching contours 10 are formed as a recess or simply as an outer rim or rim 12 of the tube plate 7, 8. It is clear here that the counterpart latching contours 10 do not have to be channels, depressions or the like, but can also be formed by a simple planar region of the tube plate 7, 8, for example a planar rim region. Specifically, this means that the counterpart latching contour 10, for example the rim 12, can transition in a surface-flush manner into the otherwise planar tube plate 7, 8. In this case, the housing 3 and the tube plates 7, 8, just like the flat tubes 5, are formed from metal, for example from aluminium, wherein such a configuration made of aluminium not only has the advantage of it being possible to form the exhaust gas heat exchanger 1 easily but also has the advantage of achieving high heat transfer on account of the high thermal conductivity of aluminium. A sealed connection between the housing 3 and the tube plates 7, 8 or the flat tubes 5 and the tube plates 7, 8 can take place for example by soldering or welding.

(7) In order to be able to fix the individual components, in particular the two tube plates 7, 8, immovably during the subsequent sealing process, that is to say for example the operation of welding or soldering to the housing 3, the latching contours 9 are provided according to the invention. Via such latching contours 9 and counterpart latching contours 10 arranged on the tube plates 7, 8, in particular the previously necessary welding frames or soldering frames, which were not only heavy and thus difficult to handle, but which also required a high cycle time and thus increased manufacturing or production costs, can be dispensed with entirely.

(8) On viewing the latching contours 9 according to FIGS. 1 and 2, it is possible to see that they are arranged at least partially circumferentially at the rim of the housing 3, such that the associated tube plate 7, 8 is clamped in place in between. The individual latching contours 9, which are configured as latching hooks 11 in the present case, thus provide a stop in the plane direction of each tube plate 7, 8, and also orthogonally thereto.

(9) In order to be able to produce the latching contours 9 cost-effectively, they can be formed in one piece with the housing 3, in particular produced in a common pressure casting operation. Of course, purely theoretically, a separate configuration of the individual latching contours 9, for example as clips, is also conceivable. Such clips could be dispensed with entirely after the welding/soldering process, but require increased assembly effort.

(10) The exhaust gas heat exchanger 1 according to the invention is produced as follows: first of all, the metal housing 3, a plurality of flat tubes 5 and two tube plates 7, 8 are provided, wherein a first tube plate 7 is fixed on the housing 3 on one side of the housing 3 via the housing-side latching contours 9. Subsequently, the flat tubes 5 are introduced into the associated rim holes 6 in the tube plate 7 and are positioned in the housing 3. Next, the second tube plate 8 on the opposite side is placed on the housing 3 such that the flat tubes 5 pass into the associated rim holes 6 in the second tube plate 8 and are held thereby. Subsequently, the second tube plate 8 is pressed against the housing 3 until the latching contours 9 engage behind the counterpart latching contours 10 on the second tube plate 8 and thus fix the tube plate 8 on the housing 3. In this now preassembled state, the subsequent sealing process, i.e. soldering in a soldering furnace or welding, can take place.

(11) By means of the latching contours 9 according to the invention and the associated counterpart latching contours 10, the individual components 7, 8 can be pre-fixed easily to the housing 3, and at the same time fixing during a subsequent soldering/welding process can be achieved without previously necessary soldering frames/welding frames that are difficult to handle and expensive being necessary for this purpose.