Drawn cup-type heat exchanger

Abstract

A structure of a drawn cup-type heat exchanger of improved pressure tightness is provided. A drawn cup-type heat exchanger is configured by stacking in plural number a long and thin tube element containing an inner fin inside a pair of cup plates. The cup plates have a flat containing portion containing the inner fin and a pair of cup portions communicating with both end portions of the containing portion; a circulation hole for communicating fluid into each of tube elements to be stacked is formed in the cup portions; and, to position both end portions in a longitudinal direction of the inner fin to be contained in front of the circulation hole of the cup portions, a corner portion is formed at at least one end portion in a width direction at both extremities in a longitudinal direction of the containing portion.

Claims

1. A drawn cup-type heat exchanger configured by stacking a plurality of a long and thin tube elements each containing an inner fin inside a pair of cup plates, wherein each of the cup plates has a flat containing portion containing the inner fin and a pair of cup portions communicating with both end portions of the containing portion; a circulation hole is formed in each of the cup portions for communicating fluid into each of the tube elements; and, to position both end portions in a longitudinal direction of the inner fin so as to contain the inner fin in the containing portion in front of the circulation hole of the cup portions, a corner portion is formed at at least one end portion in a width direction at both extremities in a longitudinal direction of the containing portion; wherein side walls of the cup portions of adjacent ones of the cup plates overlap so that there are outer side walls and inner side walls and pairs of the adjacent cup plates having overlapping side walls form respective ones of the tube elements; wherein a height of the inner side wall of each overlapping pair of the side walls does not exceed a height of the inner fin contained in the tube element formed by the cup plates having the overlapping pair of the side walls; wherein a step is formed on an inner face of the outer side wall of each overlapping pair of the side walls by an outward bend formed on the outer side wall, and a free edge of the inner side wall of the overlapping pair of the side walls is in contact with at least a part of the outward bend forming the step; and wherein the outward bend forming the step on the inner face of the outer side wall with which the free edge of the inner side wall is in contact is only at longitudinal extremities of the cup plates.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 illustrates a partially exploded perspective view showing in an exploded state a part of plural tube elements to be stacked, in an embodiment of the heat exchanger of the present invention.

(2) FIG. 2 illustrates a partial side cross-sectional view showing a state where respective tube elements in FIG. 1 are stacked each other.

(3) FIG. 3 illustrates a plan cross-sectional view seen along a arrow in FIG. 2.

(4) FIG. 4 illustrates a partial side cross-sectional view showing a state where respective tube elements are stacked each other, which is a second embodiment of the heat exchanger of the present invention.

(5) FIG. 5 illustrates a plan cross-sectional view seen along a V-V arrow in FIG. 4.

(6) FIG. 6 illustrates a partial side view showing a third embodiment of the present invention.

(7) FIG. 7 illustrates a plan view of the same.

(8) FIGS. 8A and 8B illustrate a principal part-enlarged cross-sectional view of the same.

(9) FIG. 9 illustrates a principal part cross-sectional view of the same.

(10) FIG. 10 illustrates a partial side cross-sectional view showing a state where respective tube elements are stacked each other in a conventional heat exchanger.

(11) FIG. 11 illustrates a plan cross-sectional view seen along a VII-VII arrow in FIG. 10.

DESCRIPTION OF EMBODIMENTS

(12) Next, an embodiment of a tube element that is a component of the heat exchanger of the present invention will be explained on the basis of the drawings. FIG. 1 illustrates a partially exploded perspective view showing in an exploded state a part of plural tube elements to be stacked, and FIG. 2, FIG. 3 illustrate a state where the tube elements 1 in FIG. 1 are stacked. Meanwhile, in a case where respective members in each drawing in embodiments of the present invention are approximately the same as respective members in above-described FIG. 10, FIG. 11, the same symbols as those in FIG. 10, FIG. 11 are given and duplicated explanations will be omitted as far as possible.

(13) In FIG. 1, the tube element 1 is configured of an upper side cup plate 2a and a lower side cup plate 2b, each of which is long and thin, and an inner fin 3 interposed between both cup plates 2a, 2b. Then, an outer peripheral edge of the cup plate 2a on the upper side is fitted to an inner peripheral of the cup plate 2b on the lower side. The peripheral edge of the cup plate 2b on the lower side is formed with a step and the outer peripheral edge of the peripheral edge expands outward, an expanding portion 8b guiding smoothly an edge portion of the cup plate 2a on the upper side. Furthermore, an outer fin 7 is arranged between respective tube elements 1 stacked vertically. Meanwhile, what is shown on the lowermost side is a bottom plate 8, which has the same planar shape as that of the cup plate 2b on the lower side. In this example, on a bottom surface of cup portions at both ends in the longitudinal direction of this bottom plate 8, a circular convex portion 8a is formed toward the upper direction in the stacking direction, but the circular convex portion 8a may be omitted. The cup plates 2a, 2b, the inner fin 3 and the outer fin 7 have metallic quality of material such as aluminum alloy or stainless steel, and, as to the shape of the inner fin 3, known fins such as an offset fin can be used.

(14) In a state where a pair of cup plates 2a, 2b are arranged vertically while facing each other, a containing portion 4 having a square shape in plan view is formed at the central portion in the longitudinal direction of these, and at both end portions in the longitudinal direction thereof, a cup portion 5, which has a flat cup-like shape with a rectangular-circular planar shape and a height higher than the containing portion 4, is formed. The inner fin 3 is arranged inside the containing portion 4 of the cup plates 2a, 2b. Furthermore in the bottom of the cup portion 5, a circulation hole 6 in an approximately circular shape for circulating fluid in the stacking direction is formed. Note that the circulation hole 6 is formed coaxially for each of a vertical pair of the cup plates 2a, 2b.

(15) The width of the containing portion 4 of the cup plates 2a, 2b is formed slightly larger than the width of the cup portions 5 communicating with both end portions thereof. Then corner portions 9 are formed in four portions at the boundary between both end portions in the longitudinal direction of the containing portion 4 and the rectangular portion of the rectangular-circular portion of the cup portion 5. In this embodiment, each of the corner portions 9 inclines relative to the longitudinal direction of the cup plates 2a, 2b, but the corner portion 9 may be formed orthogonally instead of the inclination.

(16) As shown in FIG. 3, both portions in the width direction of extremities in the longitudinal direction of the inner fin 3 is positioned in a state of being in contact with a pair of corner portions 9 of the containing portion 4.

(17) As shown in FIG. 2, the cup portions 5 facing each other are in a state where the side faces 10 along the circulation direction of the circulation hole 6 in respective cup portions 5 overlap each other. In the drawing, a step portion 11 is formed outward on the side face 10 of the cup portion 5 on the lower side, and the end portion of the side face 10 rising from the step portion 11 is expanded outward to form there the expanding portion 8b. Moreover, the end portion of the side face 10 of the cup plate 2a lying on the inside in the overlap does not project into the other cup plate 2b side exceeding the height of the inner fin 3. Note that, in FIG. 1, these step portions 11 and outward expansion of the end portion of the side face 10 are omitted for the purpose of avoiding complication of the drawing.

(18) As a consequence of forming a state where the side faces 10 are overlapped each other as described above, the joining portion between the cup portions 5 is made to be small to configure a compact heat exchanger. Moreover, by expanding outward the end portion of the side face 10 to form the expanding portion 8b, it is possible to guide the edge portion of the side face 10 of the cup plate 2a on the upper side to the expanding portion 8b. Consequently, a fitting operation of the side faces 10 thereof is easy to improve the operating efficiency thereof.

(19) Moreover, since the end portion of the side face 10 of the cup plate 2a does not project into the other cup plate 2b side exceeding the height of the inner fin 3, it is possible to make the end face of the side face 10 of the cup plate 2a even on an approximately the same plane over the entire circumference of the cup plate 2a, while making the same conform the end face of the side face 10 in the containing portion 4, to thereby improve molding processability by press processing and a material yield of the cup plate 2a.

(20) In a state as positioned in FIG. 2, FIG. 3, each of members configuring the tube element 1, and the outer fin 7 etc. are joined integrally by brazing. In a case where a heat exchanger is configured of an aluminum material, a cladding material covered with a brazing material can be used as a plate.

(21) FIG. 4, FIG. 5 illustrate, in accordance with FIG. 2, FIG. 3, a second embodiment of the tube element 1 in the heat exchanger of the present invention. A different point of this embodiment from the embodiment in FIG. 2, FIG. 3 is that both extremities in the longitudinal direction of the inner fin 3 contained in the containing portion 4 of the tube element 1 slightly project into the inside of the cup portion 5 from the containing portion 4, and the embodiment is formed while other points are in the same way as the above-described Example.

(22) In this embodiment, a length in the longitudinal direction of the inner fin 3 is set to be slightly longer than the length in the longitudinal direction of the containing portion 4. Then as shown in FIG. 4, the extremity of the inner fin 3 projects into the inside of the cup portion 5 by the slightly longer amount. As a consequence of forming a fillet by brazing on the projecting part, joining areas between the cup plates 2a, 2b and the inner fin 3 increase more and stress concentration at the joining portion is relaxed to thereby improve pressure tightness more. As to the projecting amount, for example, in a case where an offset fin is used for the inner fin 3, several pitches or less of the offset pitch (dimension from a certain offset to the subsequent offset) suffice, and less than one pitch may be acceptable. The projecting part receives pressure of fluid, and therefore an excess projection causes snapping of the inner fin 3 at the part. Meanwhile, as another positioning method, four corners of the inner fin 3 may be formed in a shape conformed to the inclined face of the corner portions 9 of the cup plates 2a, 2b as shown in FIG. 5 to position the cup plates 2a, 2b and the inner fin 3 with both inclined faces.

(23) Next, FIG. 6 illustrates a partial side view of a third embodiment of the present invention, FIG. 7 illustrates a plan view of the same, FIGS. 8A, 8B illustrate a principal part-enlarged cross-sectional view of the same, and FIG. 9 illustrates a cross-sectional view along A-A in FIG. 7. Different points of this embodiment from the above-described embodiment are shapes of the step portion 11a and the side face 10 seated on it. In the A-A cross-sectional position in FIG. 7, the step portion 11a evaginates to the outside in a radius direction and is formed as in FIG. 8A, on which a lower end face 10a of the side face 10 of the other cup plate is seated. In this case, the side face 10 evaginates outward so that the lower end face 10a thereof is aligned with the step portion 11a.

(24) As a consequence of performing joining by brazing in a state where the lower end face 10a of the side face 10 of the other cup plate is in contact with the bottom of the step portion 11a as described above, even in a case where a compressive load is applied in the stacking direction of each of the cup plates 2a, 2b to secure the contact of these members in a joining process, the load is supported with the step portion 11a so as not to cause displacement or deformation in the fitting portion of the cup plates 2a, 2b that form vertically a pair with each other.

(25) On the other hand, in the cross-sectional position of B-B in FIG. 7, the step portion 11 is formed, as in FIG. 8B, in the same shape as that in the embodiment in above-described FIG. 4.

(26) As a consequence of forming the step portion 11a supporting the load only in a limited vicinity of the extremity in the longitudinal direction of the cup plate in this way, it is possible to make the evagination of the cup plate minimum and to secure sufficiently the opening area of the circulation hole, and a heat exchanger with a small size, low circulation resistance and good assemblability can be provided.

INDUSTRIAL APPLICABILITY

(27) The present invention can be utilized for a heat exchanger of a drawn cup-type such as an oil cooler.

REFERENCE SIGNS LIST

(28) 1: tube element

(29) 2a: cup plate

(30) 2b: cup plate

(31) 3: inner fin

(32) 4: containing portion

(33) 5: cup portion

(34) 5a: step portion

(35) 6: circulation hole

(36) 7: outer fin

(37) 8: bottom plate

(38) 8a: circular convex portion

(39) 8b: expanding portion

(40) 9: corner portion

(41) 10: side face

(42) 10a: lower end face

(43) 11: step portion

(44) 11a: step portion