SE542234C2

SE542234C2 - A method for manufacturing of an expansion tank

Info

Publication number: SE542234C2
Application number: SE1650141A
Authority: SE
Inventors: Mikael Karlsson; Tomas Klingberg
Original assignee: Scania Cv Ab
Priority date: 2016-02-05
Filing date: 2016-02-05
Publication date: 2020-03-17
Also published as: DE102017000612A1; SE1650141A1

Abstract

The present invention relates to an expansion tank and a method for manufacturing such an expansion tank. The expansion tank comprising at least two tank parts (1, 2) which in a connected state form an expansion tank with a primary inner A first tank part (1) of said tank parts (1, 2) comprises at least one attaching portion (1i) for optional attachment of a first portion (4a) of a volume occupying unit (4) which in an attached state reduces the primary inner volume of the expansion tank when the tank parts (1, 2) are in a connected state..

Description

A method for manufacturing of an expansion tank BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates to a method for manufacturing of an expansion tank.

The coolant in a cooling system occupies a larger volume when it is warm than when it is cold. To cater for a change of volume of the coolant during operation, the cooling system is provided with an expansion tank. The expansion tank takes the form of a confined space which contains air and a certain amount of coolant. High demands are made on a cooling system cooling a combustion engine in a vehicle in order to reduce fuel consumption and emissions from the combustion engine. An optimized cooling system requires an expansion tank having an inner volume which varies with the required cooling capacity of the cooling system. The required cooling capacity of a cooling system varies with the capacity of the combustion engine. Furthermore, cooling system can be used to cool other components and mediums in a vehicle such as, for example, charge air, recirculating exhaust gases, refrigerant in an air conditioning system, gearbox oil, and retarder oil. Thus, the required cooling capacity of cooling system may vary widely for different kinds of vehicle. As a consequence, expansion tanks are manufactured in a relatively large number of different sizes.

It is known to manufacture expansion tanks by two prefabricated tank halves which are joined together. The two tank halves can be produced in an injection molding process. However, injection molding tools are expensive and it is costly to provide separate injection molding tools for each different sized expansion tank.

US 2007/0235458 shows a modular liquid reservoir comprising a plurality of shell sections that in an assembled state define a fluid tight reservoir volume. The reservoir includes a pair of end cap shells which may be joined together. It is possible to arrange an expansion shell section between the pair of end cap shells in order to form a reservoir of a larger size.

DE 102007 029 024 shows a volume changeable container for liquid in a vehicle. The volume-changeable container has a flexible area in a wall of the container. The flexible area is arranged in such a way that it is pushed in or pulled out so that a recess is developed when pushing and a bulge is developed when pulling.

SUMMARY OF THE INVENTION The object of the present invention is to provide a method for manufacturing of an expansion tank for coolant in a cooling system, which makes it easy to change the inner volume of the expansion tank.

The above mentioned object is achieved by the method according to claim 1. The expansion tank is formed by at least two tank parts which in a connected state form an expansion tank with a primary inner volume. Preferably, the primary inner volume is adapted to a cooling system of a high capacity. A first tank part may comprise one or several attaching portion for optional attachment of a first portion of volume occupying unit. Consequently, it is possible to attach or not to attach a volume occupying unit to each attaching portion of the first tank part. Each volume occupying unit attached to the first tank part decreases the inner volume of the expansion tank. The use of such volume occupying units with a well-defined volume makes it easy reduce the primary inner volume of the expansion tank to a suitable smaller inner volume with a high accuracy. Furthermore, the same tank parts may be used to manufacture expansion tanks of different inner volumes which significantly reduces the tool costs for manufacturing of the tank parts.

According to an embodiment of the invention, a second tank part of said tank parts comprises at least one portion for attachment of a second portion of a volume occupying unit. In this case, the volume occupying unit will be attached to the first tank part as well as to the second tank part. As a consequence, the volume occupying unit obtains a secure attachment in the expansion tank.

According to an embodiment of the invention, the attaching portion of the first tank part and the attaching portion of the second tank part are designed as projecting portions. The projecting portion may be an arbitrary shaped projecting portion such as a pin-shaped portion. The first portion and the second portion of the volume occupying unit may comprise a recessed portion configured to receive the projecting portion of the tank parts. Alternatively, the tank parts may comprise recessed portions and the volume occupying member may comprise projecting portions of a complementary design.

According to an embodiment of the invention, the first tank part comprises a wall of the expansion tank and the second tank part comprises an opposite wall of the expansion tank. The first tank part may comprise a vertical side wall of the expansion tank and the second tank part may comprise an opposite vertical side wall of the expansion tank. In this case, a volume occupying unit may have an extension between the side walls.

According to an embodiment of the invention, the first tank part comprises a first tank half of the expansion tank and the second tank part comprises a second tank half of the expansion tank. In this case, the first tank half and the second tank half may have a substantially mirrored design. However, it is possible to manufacture the first tank part and the second tank part such they contains different sized parts of the expansion tank. Furthermore, it is possible to form the expansion tank by more tank parts than two.

According to an embodiment of the invention, the volume occupying unit is shaped as a right circular cylinder. Such a volume occupying unit has a circular circumference which facilitates the air flow past the volume occupying member in the expansion tank. Furthermore, it is easy to attach such a shaped occupying member to the first tank part and the second tank part because it is possible to attach it in an arbitrary angular position.

According to an embodiment of the invention, the expansion tank may enclose at least two volume occupying units of different volumes. In this case, volume occupying members of different size is used, which further facilitates the reduction of the inner volume of the expansion tank to a suitable size with a high accuracy.

According to an embodiment of the invention, the expansion tank includes a connecting area where the prefabricated parts are sealingly connected to each other. Since an expansion tank contains coolant and air with a positive pressure, it is important that the tank parts a sealingly connected to each other in a relatively strong manner. Preferably, the tank parts a sealingly connected to each other by heat welding.

BRIEF DESCRIPTION OF THE DRAWINGS In the following preferred embodiments of the invention are described, as examples, with reference to the attached drawings, in which: Fig. 1 shows a first tank part of an expansion tank according to the invention, Fig. 2 shows a second tank part of an expansion tank according to the invention, Fig. 3 shows a cross section view of the first tank part and the second tank part in a connected state, Fig. 4 shows a volume occupying unit according to a first embodiment, Fig. 5 shows a volume occupying unit according to a second embodiment and Fig. 6 shows a flowchart according to a method for manufacturing of an expansion tank.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Fig. 1 shows a first tank part 1 of an expansion tank. The expansion tank is preferably used in a cooling system cooling a combustion engine in a vehicle. The first part 1 comprises a first half of the expansion tank. The first tank part 1 comprises a first side wall 1a of the expansion tank, a portion 1b of an upper wall of the expansion tank, a portion 1c of a bottom wall of the expansion tank, a portion 1d of a second side wall of the expansion tank and a portion 1e of a third side wall of the expansion tank. The walls 1a-1e of the first tank part 1 define a substantially bowl-shaped body having a first inner space. A plurality of inner wall sections 1g is arranged in the inner space of the first tank part 1. A number of mounting members 1h are arranged on the outside of the wall portions 1b, 1d, and 1e. A plurality of first attaching portions 1i are arranged on an inner surface of the first side wall 1a. In this case, each first attaching portion 1i comprises a projecting portion having an extension from an inner end fixedly arranged on the inner surface of the first side wall 1a to a free end arranged at a distance from the inner surface of the first side wall 1a. A connection unit 1j for attachment of a static line is arranged at the bottom wall portion 1c. Further connection units 1k are arranged at a lower part of the second wall portion 1d for attachment of deaeration lines for deaeration of specific parts of the cooling system.

Fig. 2 show a second tank part 2 of the expansion tank. The second part 2 comprises a second half of the expansion tank. The second tank part 2 comprises a fourth side wall 2f of the expansion tank, a portion 2b of the upper wall of the expansion tank, a portion 2c of the bottom wall of the expansion tank, a portion 2d of a second side wall of the expansion tank and a portion 2e of the third side wall of the expansion tank. The walls portions 2b-2f of the second tank half 2 defines a substantially bowl-shaped body having a second inner space. The second inner space comprises a plurality of inner wall sections 2g which together with the inner wall sections lg of the first tank part 1 form flow passages for the coolant and the air in the expansion tank. Furthermore, the inner wall sections lg, 2g add strength to the first tank part 1 and the second tank part 2.

A number of mounting members 2h are arranged on the outside of the wall portion 2b, 2d, 2e configured to come in contact with the mounting members 1h of the first tank part 1. The mounting member 1h, 2h comprises holes for a bolt or the like for mounting of the expansion tank in a suitable position in a vehicle. A plurality of second attaching portions 2i are arranged on an inner surface of the fourth side wall 2f. Each second attaching portion 2i comprises a projecting portion having an extension from an inner end fixedly arranged on the inner surface of the fourth side wall 2f to a free end arranged at a distance from the inner surface of the fourth side wall 2f. Each second attaching portion 2i of the second part 2 is arranged in an opposite position to a first attaching portions li of the first part 1. In this case, the second tank part 2 is a mirror copy of the first tank part 1 except that it lacks connection units 1j, 1k. The tank parts 1, 2 are prefabricated units. Each tank part 1, 2 can be produced in an injection molding process by, for example, a propene plastic or another suitable material.

Fig. 3 shows a cross section view of the first tank part 1 and the second tank part 2 in a connected state. However, the inner wall sections 1g, 2g of the tank halves are not shown. The two tank parts 1, 2 are joined together by heat welding along a connection area 3. The first side wall la of the first tank part 1 and the fourth side wall 2f of the second tank part 2 form opposite side walls in the expansion tank. The first inner space of the first tank half 1 and the second inner space of the second tank half 2 defines together a primary inner volume of the expansion tank. Two volume occupying units 4 occupy a part of the primary volume of the expansion tank. The volume occupying members 4 reduce the inner volume of the expansion tank receiving the coolant and the air. Fig. 4 shows one such volume occupying unit 4 more in detail. The volume occupying unit 4 is shaped as a right circular cylinder. It comprises a first connecting portion in the form of a first recessed portion 4a located at a first end surface and a second connecting portion in the form of a second recessed portion 4b located at a second end surface. The first recessed portion 4a is configured to receive one of the first projecting portions li of the first tank part 1 and the second recessed portion 4b is configured to receive an opposite arranged second projecting portion 2i of the second tank part 2.

Fig. 5 shows an alternative embodiment of a volume occupying unit 4. Also in this case the volume occupying unit 4 is shaped as a right circular cylinder. The volume occupying member 4 comprises a first connecting portion in the form of a first projecting portion 4c at a first end surface and a second connecting portion in the form of a second projecting portion 4d at a second end surface. The first projecting portion 4c is configured to be received in a not shown complimentary shaped recessed portion of the first tank part and the second projecting portion 4d is configured to be received in a not shown complementary shaped recessed portion of the second tank part 2.

Fig 6 illustrates a flowchart of a method for manufacturing of the expansion tank. The method starts at step 10. At step 11, at least two prefabricated tank parts 1, 2 are received which are to form the expansion tank in a connected state. The prefabricated tank parts 1 can be produced in an injection molding process by, for example, a suitable plastic material. By means of information of the capacity of the cooling system, it is evaluated, at step 12, if the primary inner volume of the expansion tank is to be reduced or not.

If it is evaluated, at step 12, that the primary inner volume of expansion tank formed by the prefabricated parts 1, 2 is too large for the cooling system, the primary inner volume of the expansion tank is to be reduced. At step 13, there is access to a plurality of volume occupying units 4 which can be attached to the first part 1. The volume occupying units 4 may be of the same size or varying sizes. It is evaluated how many volume occupying members 4 to be attached to the first parts 1, 2 and probably the size of the volume occupying members 4. The first recessed connecting portion 4a of each volume occupying members 4 are attached on a respective first projecting attaching portion 1i of the first tank part 1. When all volume occupying members 4 have been attached to the first tank part 1 the method continues at step 14. At step 14, the second tank part 2 are moved towards a connected state with the first tank part 1. During this movement, the second projecting attachment portions 2i of the second tank part 2 is introduced into a respective second recessed connection portion 4b of the volume occupying members 4. When the first tank part 1 and the second tank part 2 have reached a connected state, the volume occupying members 4 are securely fastened in the inner space formed by the first tank part 1 and the second tank part 2. At step 15, a sealed connection 3 is provided between the tank parts 1, 2. An expansion tank with a reduced inner volume is now ready to be mounted in the vehicle.

If instead, at step 12, the primary inner volume of expansion tank formed by the prefabricated parts 1, 2 is of a suitable size for the cooling system, the method continues at step 15. At step 15, the prefabricated parts 1, 2 are heat welded together such that a sealed connection 3 is performed between the tank parts 1, 2. The expansion tank is now ready to be mounted in the vehicle without any volume occupying members 4.

The possibility to reduce the inner volume of an expansion tank with an arbitrary number of volume occupying members 4, makes it possible to provide expansion tanks with a variable inner volume in a simple manner. Furthermore, it is possible to use the same tank parts in all expansion tanks. As a consequence, the cost for injection moulding tolls for the including tank parts is low. The volume occupying members 4 may have a relatively simple design and be manufactured to a low cost. The volume occupying members 4 may be manufactured of the same material as the tank parts 1, 2.

The invention is not restricted to the described embodiment but may be varied freely within the scope of the claims.

Claims

1. A method for manufacturing of an expansion tank, wherein the method comprises the step of - receiving at least two tank parts (1, 2) of an expansion tank which in a connected state form an expansion tank with a primary inner volume, - evaluating whether the primary inner volume of the expansion tank should be reduced, - providing such a possible reduction by attaching at least one volume occupying unit (4) to a first tank part (1) of said tank parts (1, 2), - attaching the volume occupying unit (4) to a second tank part (2) of said tank parts (1, 2) and - providing a sealed connection between the tank parts (1, 2).

2. A method according to claim 1, wherein the method comprises the step of - attaching the volume occupying unit (4) to the second tank part (2) when said parts (1, 2) are moved to the connected state.

3. A method according to claim 1 or 2, wherein the first tank part (1) comprises at least one attaching portion (1i) for optional attachment of a first portion (4a, c) of a volume occupying unit (4) which in an attached state reduces the primary inner volume of the expansion tank when the tank parts (1, 2) are in the connected state.

4. A method according to claim 3, wherein the second tank part (2) comprises at least one attaching portion (2i) for attachment of a second portion (4b, d) of a volume occupying unit (4).

5. A method according to claim 4, wherein the attaching portion (1i) of the first tank part (1) and the attaching portion (2i) of the second tank part (2) are designed as projecting portions.

6. A method according to claim 5, wherein the first portion (4a) and the second portion (4b) of the volume occupying unit (4) are designed as recessed portions configured to receive a respective projecting portion (li, 2i) of the first tank part (1) and the second tank part (2).

7. A method according to any one of the preceding claims 4 to 6, wherein the first tank part (1) comprises a wall (1a) of the expansion tank and the second tank part (2) comprises an opposite wall (2f) of the expansion tank.

8. A method according to claim 7, wherein the volume occupying unit (4) has an extension between the wall (la) of the first tank part (1a) and the opposite wall (2f) of the second tank part (2) in an attached state.

9. A method according to any one of the preceding claims, wherein the first tank part (1) comprises a first tank half of the expansion tank and the second tank part comprises a second tank half (2) of the expansion tank.

10. A method according to any one of the preceding claims, wherein the volume occupying unit (4) is shaped as a right circular cylinder.

11. 1 1. A method according to any one of the preceding claims, wherein the expansion tank is made to enclose at least two volume occupying units (4) of different volumes.

12. A method according to any one of the preceding claims, wherein the expansion tank includes a connecting area (3) where the tank parts (1, 2) are sealingly connected to each other.