JP6292844B2 - Heat exchanger - Google Patents

Description

  The present invention relates to a so-called multi-plate heat exchanger in which a plurality of flat tubes serving as flow paths for the first fluid are stacked and a gap serving as a flow path for the second fluid is secured between the flat tubes. Regarding improvement.

  As a so-called multi-plate heat exchanger, as described in Patent Document 1, for example, an oil flow path is formed inside by joining an oval first plate and a second plate to each other at the periphery thereof. There has been known an oil cooler that includes a formed flat tube and is formed by stacking a plurality of flat tubes in a plurality of stages such that a gap serving as a cooling water flow path is formed between the flat tubes. This type of oil cooler is used, for example, in a form housed in a case provided in a cylinder block of a large engine, and the engine coolant is forcibly circulated in the case, while oil is contained in the oil cooler. The oil is cooled and oil is cooled by heat exchange between the two.

  The first plate and the second plate are made of a so-called clad material, for example, and are joined to each other with the fin plate sandwiched therebetween by brazing by heating in a furnace. That is, the peripheral edge of the first plate and the peripheral edge of the second plate are abutted and brazed to each other, and the first plate and the second plate are disposed on both upper and lower surfaces of the fin plate inside the oil passage. Each of the two plates is brazed.

  Then, between the flat tubes of each stage, the peripheral edge of the opening serving as the oil inlet and oil outlet of each plate is formed one step higher in a boss shape on one plate, and this is sequentially connected to form a stack. An oil inlet passage and an oil outlet passage that are continuous in the direction are formed, whereby the oil passages in the respective flat tubes communicate with each other. The oil inlet passage and the oil outlet passage are respectively connected to an oil inlet and an oil outlet provided in a mounting flange of the oil cooler.

JP 2001-90518 A

  In the conventional heat exchanger as described above, each flat tube has a certain width, whereas there is one opening provided at the end of the flat tube. As a fluid flow distribution, there is a tendency that only the central portion of the flat tube flows linearly from the opening at one end serving as the inlet of each flat tube to the opening at the other end serving as the outlet. Therefore, the entire width of the flat tube cannot be effectively used for heat exchange, and there is room for improvement in terms of heat exchange efficiency.

  Also, if a plurality of openings are provided at each end of the flat tube, the oil flow is divided or merged in order to connect to an oil inlet or outlet which is generally a single opening. A connector made of a separate member is required, the configuration becomes complicated, and the oil inlet or outlet may be enlarged.

The present invention is a heat exchanger in which a flat tube whose inside is a flow path for a first fluid is stacked in a plurality of stages via a gap which is a flow path for a second fluid, A first plate and a second plate joined to each other at the periphery, and a fin plate sandwiched between the first plate and the second plate, and two adjacent flat tubes, An opening provided at each end in the longitudinal direction of the second plate of one flat tube and an opening provided at each end in the longitudinal direction of the first plate of the other flat tube are mutually connected. In the heat exchanger in which the first fluid flows in the longitudinal direction of each flat tube through these openings, which are communicated with each other by being joined,
At each end in the longitudinal direction of the first plate in the lowermost flat tube, a single opening serving as a fluid inlet or a fluid outlet of the heat exchanger is formed as the opening.
At each end in the longitudinal direction of the second plate combined with the first plate, as the opening, a pair of openings are arranged side by side in the width direction of the flat tube,
The pair of openings in the second plate are such that the opening edges of the adjacent portions form a straight line along the longitudinal direction of the flat tube, and the opening edges of the portion toward the longitudinal center of the flat tube are A straight line along the width direction is formed, and a corner portion constituted by these two straight line portions is located in a single opening of the first plate when projected in the stacking direction. Yes.

  In the heat exchanger configured as described above, the first fluid flows through a single opening in the lowermost flat tube on the equipment side through which the first fluid such as oil flows. Part of the inflowing first fluid flows in the longitudinal direction in the lowermost flat tube and flows out from the single opening at the other end to the device side. The other part of the first fluid that has flowed in flows into the second-stage flat tube through the opening of the second plate. At this time, in the second plate and the corresponding second-stage flat tube, there is a pair of openings arranged in the width direction of the flat tube, and a pair of openings serving as outlets at the other end. Therefore, the first fluid flows in the flat tube with widening in the width direction. Therefore, heat exchange is performed more efficiently in the entire width direction of the flat tube.

  That is, according to the present invention, the flow from the single opening to the pair of openings is divided or the flow from the pair of openings to the single opening is merged inside the lowermost flat tube. There is no need for a connector made of members.

  Here, when a single opening of the first plate and a pair of openings of the second plate are projected in the laminating direction of the flat tubes, the passage resistance between the two is influenced by the degree of overlap between the two. The The larger the area where both overlap, the more smoothly the first fluid flows. In the present invention, the pair of openings of the second plate are non-circular and are constituted by a linear opening edge along the longitudinal direction of the flat tube and a linear opening edge along the width direction of the flat tube. The corner is located within a single opening in the second plate. Therefore, compared with a case where the pair of openings are circular, the area overlapping with the single opening is increased, and the first fluid flows smoothly.

  In a preferred embodiment, the remaining part of the pair of openings has an arc shape.

  Moreover, in one preferable aspect, the edge part of the longitudinal direction of the said fin plate has comprised the linear form along the width direction of a flat tube, and is located along the opening edge of a pair of opening part.

  In a preferred embodiment, the second and subsequent flat tubes are provided with a pair of openings at each end corresponding to the second plate of the lowermost flat tube.

  According to this invention, the first fluid can be allowed to flow in a form that is widened in the width direction of the flat tube, and the heat exchange efficiency can be improved without an unnecessary increase in passage resistance. Moreover, since the flow is expanded in the width direction inside the lowermost flat tube, the connection structure between the equipment and the heat exchanger may be complicated, and the size of each part including the heat exchanger may be increased. Absent.

  Further, it is possible to secure a large area where a single opening in the first plate overlaps with a pair of openings in the second plate, and to reduce the passage resistance of the first fluid.

The perspective view of the oil cooler used as one Example of this invention. The front view of the oil cooler. Explanatory drawing which shows the state which accommodated the oil cooler in the case. The exploded perspective view of the flat tube of the lowest step. The exploded perspective view of the flat tube after the 2nd step. Sectional drawing of the principal part of the flat tube along the AA line of FIG. The perspective view which expands and shows a part of fin plate. The top view which shows the one end part of an upper side plate. The perspective view which similarly shows the one end part of an upper plate. The top view which shows the one end part of an oil cooler from the lower side.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  1 and 2 show a multi-plate oil cooler 1 as an embodiment of a heat exchanger according to the present invention. The oil cooler 1 is used for cooling lubricating oil of a large engine, and a plurality of flat tubes 2 each having an oil flow path 11 (see FIG. 6) are stacked, and a gap between the flat tubes 2 is provided. It becomes the cooling water flow path 12 (refer FIG. 6). In addition, it is possible to increase / decrease the heat exchange capacity | capacitance as the oil cooler 1 by changing the step number of the flat tube 2 laminated | stacked, and the step number of the flat tube 2 is set according to required heat exchange capacity | capacitance. As shown in FIG. 3, the oil cooler 1 is used in a state where the oil cooler 1 is accommodated in a case 10 in which cooling water (W) flows in the longitudinal direction. For example, the case 10 may be configured as a recess in a part of the cylinder block of the engine, or may be a separate independent box.

  As shown in FIGS. 1 and 2, the oil cooler 1 has a plurality of flat tubes 2, a pair of mounting flanges 3 that respectively constitute oil inlets and outlets, and a plurality of flat tubes 2. A pair of reinforcing plates 4 disposed to face the flange 3. In the following description, in order to facilitate understanding, the terms “upper” and “lower” are used on the basis of the vertical postures shown in FIG. 1 and FIG. That is, the side where the mounting flange 3 is located is called the lower part of the oil cooler 1, and the direction where the reinforcing plate 4 is located is called the upper part of the oil cooler 1, but the mounting posture of the oil cooler 1 in an actual vehicle is arbitrary. Yes, it is not limited to the posture as shown in FIGS.

  The flat tube 2 has an elongated strip shape as a whole so that oil flows in the longitudinal direction, and has a substantially arc shape in which both ends are gently curved. The mounting flange 3 disposed at each end of the flat tube 2 in the longitudinal direction has a relatively thick plate shape such as a rhombus or an ellipse, and has a circular opening 6 serving as an oil inlet or outlet from the engine side. It has in the center and has a pair of mounting holes 7 at both ends. The reinforcing plate 4 has an edge shape corresponding to the arc shape of the end portion of the flat tube 2 and has a relatively thick plate shape.

  As shown in FIGS. 4 and 5, one flat tube 2 includes a lower plate 21 serving as a first plate, an upper plate 22 serving as a second plate, and a fin plate 23 disposed therebetween. , Consisting of three. Each of these plates 21, 22, 23 and the mounting flange 3 and the reinforcing plate 4 are made of a metal plate such as stainless steel or iron, and are temporarily assembled in a predetermined state, and then heated in a furnace to integrate each part. It is brazed. The plates 21, 22, 23 and the like are made of a so-called clad material obtained by coating the surface of the base material with a brazing material, but a separate brazing material may be used at the time of brazing.

  The lower plate 21 of each stage of the flat tube 2 has the same configuration except for the lower plate 21A of the lowermost flat tube 2 shown in FIG. 4, and is positioned with the upper plate 22 as shown in FIG. For this reason, except that the peripheral edge rises slightly as a flange 31 over the entire circumference, it basically has a flat thin plate shape. A pair of substantially circular openings 25 are formed at both ends in the longitudinal direction of the lower plate 21, and the pair of openings 25 are arranged side by side in the width direction of the lower plate 21. Yes. The opening edge of the opening 25 is bent downward and slightly protrudes as a short cylindrical portion 32 for positioning with the upper plate 22 of another flat tube 2 positioned below. Further, at both ends of the lower plate 21 in the longitudinal direction, end protrusions 24 that protrude downward in a circular boss shape are provided. The end protrusion 24 is located outside the opening 25 in the longitudinal direction, and is located between the pair of openings 25 in the width direction of the flat tube 2.

  In the lower plate 21A of the lowermost flat tube 2, as shown in FIG. 4, one circular opening 25A is formed at each end in the longitudinal direction. Similar to the lower plate 21 of the other steps, a flange 31 is provided on the periphery. The opening 25A in the lowermost flat tube 2 has the center of the circle positioned at the center in the width direction of the flat tube 2 so as to partially overlap the pair of openings 25, and the pair of openings The opening area is larger than the individual opening area of the portion 25. The opening 25A corresponds to the circular opening 6 of the mounting flange 3, and the peripheral edge of the opening 25A is bent downward to form a short cylindrical tubular portion 26. As shown in FIG. 1, the mounting flange 3 is brazed to the lower surface of the lower plate 21 </ b> A of the lowermost flat tube 2, and the cylindrical portion 26 is formed inside the circular opening 6 of the mounting flange 3. It is fitted around the circumference.

  A pair of locking claws 26a for positioning the mounting flange 3 are cut and raised on both sides of the opening 25A. In addition, the lowermost lower plate 21A in the illustrated example includes a plurality of embosses 27 in order to avoid sticking to a jig (not shown) used during brazing in the furnace.

  As shown in FIGS. 4 and 5, the upper plate 22 of the flat tube 2 of each stage slightly rises as a flange 33 over the entire circumference, and the flange 33 is formed on the lower plate 21 (21 </ b> A). The outer shape of the lower plate 21 (21A) is slightly smaller than that of the lower plate 21 (21A) so as to closely fit inside the flange 31. A pair of substantially circular openings 28 is formed at each end in the longitudinal direction of the upper plate 22 corresponding to each pair of openings 25 at both ends of the lower plate 21. The periphery of the opening 28 is bent so as to be raised one step upward, thereby forming a boss portion 29 surrounding each opening 28 in an annular shape. In other words, the substantially circular boss portion 29 is formed to project upward, and the opening 28 is formed at the center thereof.

  In addition, a fin plate accommodating portion 30 that accommodates a rectangular fin plate 23 is formed in the middle in the longitudinal direction of the upper plate 22 so as to be recessed upward. The fin plate housing portion 30 has a rectangular shape with a dimension corresponding to the rectangle of the fin plate 23 and has a depth corresponding to the thickness of the fin plate 23. As a result, the upper plate 22 has a shallow dish shape in which the joint surface 22 a facing downward is left on the periphery and the center portion is recessed as the fin plate housing portion 30. A pair of openings 28 at each end is adjacent to the end of the fin plate housing 30 and the internal space of the boss 29 is in communication with the internal space of the fin plate housing 30. In other words, the end portion in the longitudinal direction of the fin plate housing portion 30 that has a step-like depression shape with respect to the joining surface 22 a formed from the reference surface of the base material opens toward the internal space of the boss portion 29. . And the guide wall 34 is provided in the form which extended a part of flange 33 further upwards at the side of a pair of opening part 28. As shown in FIG. As shown in FIG. 1, the guide wall 34 has an elongated strip shape along the longitudinal direction of the flat tube 2 and projects in the stacking direction (that is, upward) of the flat tube 2.

  Further, end projections 35 projecting upward in a circular boss shape are provided at both ends of the upper plate 22 in the longitudinal direction, corresponding to the end projections 24 of the lower plate 21. The end protrusion 35 is located on the outer side in the longitudinal direction of the boss 29 surrounding the opening 28, and is located between the pair of openings 28 in the width direction of the flat tube 2.

  In addition, a large number of embosses 36 projecting upward in a truncated cone shape or a hemispherical shape are formed in an intermediate portion in the longitudinal direction serving as a bottom wall of the fin plate housing portion 30. The top of the emboss 36 is at a height that matches the top surface of the boss 29 around the opening 28.

  As shown in FIGS. 4 and 5, the fin plate 23 has a rectangular shape with a simple outer shape, and has a size that fits into the fin plate accommodating portion 30. As shown in FIG. 7 in an enlarged view, a portion of the fin plate 23 is provided with a number of slits in a single base material to form a number of strips having a constant width. It consists of corrugated fins that are bent in a rectangular or U-shape, and in particular, it consists of offset corrugated fins in which the positions of the corrugations of adjacent strips are shifted from each other by a half pitch. In the present invention, the configuration of the fin plate 23 is not limited to the offset corrugated fin.

  The lower plate 21 (21A) and the upper plate 22 configured as described above are joined to each other by brazing with the fin plate 23 sandwiched therebetween. That is, the flange 33 of the upper plate 22 is fitted inside the flange 31 of the lower plate 21 (21A), and the joint surface 22a on the periphery of the upper plate 22 is superimposed on the upper surface of the lower plate 21, so that they are brazed together. Is done. Therefore, the fin plate accommodating portion 30 having a dish-like shape is covered with the flat lower plate 21 (21A), thereby forming a sealed oil flow path 11. The fin plate 23 is bent as a corrugated fin and has a space in the vertical direction. The lower surface of the fin plate 23 is brazed to the lower plate 21, and the upper surface is brazed to the upper plate 22.

  As a whole, the oil cooler 1 has a plurality of flat tubes 2 laminated together and brazed integrally as described above. At this time, the boss 29 around the opening 28 of the upper plate 22 in the flat tube 2 at a certain stage is brazed and joined to the periphery of the opening 25 of the lower plate 21 in the flat tube 2 adjacent thereto. Similarly, the top of the emboss 36 of the upper plate 22 is brazed to the lower surface of the lower plate 21. Furthermore, the end projections 24 and 35 located at both ends are butted together and brazed. As a result, a gap serving as the cooling water flow path 12 is ensured between the upper plate 22 of a certain stage and the lower plate 21 of the upper stage, while the openings 28 and the lower plate 21 of the upper plate 22 are secured. The opening 25 is connected to communicate with each other. As described above, in the state where the flat tubes 2 are stacked in a plurality of stages, the cylindrical oil ports 37 are constituted by the opening portions 25 and 28 and the boss portions 29, and each of the flat tubes 2 is formed by the oil ports 37. A continuous flow path is formed in the laminating direction that connects the internal oil flow paths 11 to each other. The upper end of the oil flow path that is continuous in the stacking direction is closed by the reinforcing plate 4. Alternatively, the upper plate 22 in the uppermost flat tube 2 may be configured so as not to include the opening 28.

  At the time of brazing, the cylindrical portion 32 at the periphery of the opening 25 of the lower plate 21 is fitted into the opening 28 of the upper plate 22 so that the upper plate of the upper plate and the upper plate of the lower plate The plate 22 is positioned relative to each other.

  In the lowermost flat tube 2, as shown in FIG. 4, a lower plate 21A having a single opening 25A and an upper plate 22 having a pair of openings 28 are combined to form a single opening 25A. The attachment flange 3 is attached to the lower surface side of the. FIG. 10 illustrates the part of the mounting flange 3 from the lower surface side. As illustrated, a part of the pair of openings 28 faces the single opening 25A. Therefore, the oil flowing from the single opening 25A is divided into the pair of openings 28 on the oil inlet side, and the oil from the pair of openings 28 is transferred to the single opening 25A on the oil outlet side. It flows together.

  As described above, the oil cooler 1 assembled integrally by brazing as described above is used in a state of being accommodated in the case 10 through which cooling water flows (see FIG. 3). Cooling water (W) forcedly circulated by a water pump (not shown) on the engine side flows along the longitudinal direction of the case 10. The oil flows from one end in the longitudinal direction to the other end using the circular opening 6 of one mounting flange 3 as an inlet and the circular opening 6 of the other mounting flange 3 as an outlet. The oil flow direction may be forward or reverse with respect to the coolant flow direction.

  Next, the configuration around the oil port 37 at the end of the flat tube 2 which is the main part of the present invention will be described in more detail. In addition, in the oil cooler 1 of the present embodiment, in order to eliminate the directionality of each of the plates 21, 22, and 23 and facilitate processing and assembly, both ends have the same configuration (that is, symmetrical shape). ing.

  As described above, the upper plate 22 has the rectangular fin plate accommodating portion 30 corresponding to the fin plate 23, and is overlapped on the lower surface of the upper plate 22 so that the flat lower plate 21 covers the fin plate accommodating portion 30. It has been. Therefore, the flat tube 2 is not swelled in a region outside the fin plate housing portion 30 in the longitudinal direction of the flat tube 2, and is basically based on the plate thickness of the upper plate 22 and the plate thickness of the lower plate 21. It becomes the thin part 38 which becomes. Therefore, in the state where a plurality of flat tubes 2 are stacked as the oil cooler 1, the gap in the stacking direction that becomes the cooling water flow path 12 is narrow in the region of the fin plate housing portion 30, and compared with this in the thin portion 38. It will be wide. When viewed as the individual flat tubes 2, the height position of the upper surface of the fin plate housing portion 30 is relatively higher than the height position of the upper surface of the thin portion 38.

  The pair of oil ports 37 (that is, the boss portions 29) rises in a cylindrical shape in an independent manner in the thin-walled portion 38, and a part of the outer periphery (specifically, the portion near the center in the longitudinal direction of the flat tube 2). The fin plate accommodating portion 30 is continuous. As a result, an inter-port passage 40 extending from the thin wall portion 38 to the end of the fin plate housing portion 30 is formed between a pair of adjacent oil ports 37. That is, the inter-port passage 40 extends from the end of the flat tube 2 in a concave groove shape in the longitudinal direction of the flat tube 2. An inclined surface that smoothly connects the height position of the thin wall portion 38 and the height position of the upper surface of the fin plate housing portion 30 to the boundary portion between the fin plate housing portion 30 and the end portion of the inter-port passage 40. 40a is provided. In the example of illustration, although the said inclined surface 40a has comprised the circular arc surface which touches the upper surface of the thin part 38 smoothly, a linear inclined surface may be sufficient.

  On the side edge side of the flat tube 2, the base portion of the side wall of the boss portion 29 constituting the oil port 37 serves as a port side guide wall 29 a from the outer peripheral surface of the boss portion 29 toward the end portion of the fin plate housing portion 30. The flat tube 2 extends in the width direction. Further, the end portions of the fin plate accommodating portion 30 have corner portions 30a that form an angle of approximately 90 ° at both ends in the width direction of the flat tube 2 in order to position the internal fin plate 23, and Between the corner portion 30 a and the oil port 37 (boss portion 29), an extension portion 30 b is formed by extending the bottom wall of the fin plate housing portion 30 in the longitudinal direction of the flat tube 2. The extended portion 30b has an outer shape defined by the outer peripheral surface of the upper half of the boss portion 29 and the port side guide wall 29a. Inside the flat tube 2, the extended portion 30b is used to accommodate the fin plate. A substantially triangular space that is continuous with the rectangular space in the portion 30 is formed. In addition, the height position of the thin portion 38 and the height position of the upper surface of the fin plate accommodating portion 30 are smoothly connected to the side edge of the extension portion 30b, that is, the region where the port side guide wall 29a and the extension portion 30b intersect. An inclined surface 41 is provided. The inclined surface 41 may be, for example, a linear inclined surface, or may be an inclined surface made of an appropriate curved surface.

  On the other hand, on the side of the oil port 37, as described above, the guide wall 34 is provided by extending a part of the flange 33 further upward. The guide wall 34 is formed in a range straddling at least the end portion (that is, the corner portion 30a) of the fin plate housing portion 30 in the longitudinal direction of the flat tube 2, and in the illustrated example, as shown in FIG. The one end 34a is located slightly outside (that is, closer to the end) than the center of the boss 29 or the opening 28, and the other end 34b is slightly outside (ie, the end) from the center of the emboss 36 closest to the end. It is located near the department.

  The guide wall 34 provided in this manner is opposed to the port side guide wall 29a extending from the oil port 37 with an appropriate interval. Thereby, in a state where the plurality of flat tubes 2 are stacked, a space surrounded by the guide wall 34, the port side guide wall 29a, and the two upper and lower thin portions 38, that is, the nozzle portion 42 is formed. The nozzle portion 42 is formed as a long and narrow space along the longitudinal direction of the flat tube 2, one end opens toward the longitudinal end portion of the flat tube 2, and the corner portion 30 a is located at the other end. . Further, since the port-side guide wall 29a has a shape that gradually expands in the width direction of the flat tube 2, the nozzle portion 42 has a tapered shape, although it is slight.

  As shown in FIGS. 1 and 2 and the like, the upper edge of the guide wall 34 is basically not in contact with the upper flat tube 2 and is extended as far as possible without touching it. Yes.

  Therefore, the cooling water introduced into the case 10 flows between the flat tubes 2 along the thin-walled portion 38 at the end, passes through between the adjacent two-stage fin plate accommodating portions 30, and exits the cooling water. Flows to the side. At this time, at the end portion on the cooling water inlet side, the flowing cooling water collides with the cylindrical oil port 37 and diverts to the left and right, and passes through the pair of left and right nozzle portions 42 and the central inter-port passage 40. Flows downstream. In the nozzle portion 42, the periphery is surrounded by the guide wall 34, the port-side guide wall 29 a, and the two upper and lower thin portions 38, so that the cooling water flows linearly along the longitudinal direction of the flat tube 2. Guided and flows downstream at high speed.

  On the other hand, the oil flows from the circular opening 6 of one mounting flange 3 serving as an oil inlet through a single opening 25A of the flat tube 2 at the bottom, and a part thereof is in the longitudinal direction of the flat tube 2. Along with flowing along, the remaining portion flows into a pair of openings 28 and is supplied to the flat tube 2 at the other stage. In the second and subsequent flat tubes 2, the oil flows from the pair of openings 25 in the longitudinal direction of the flat tubes 2, so heat exchange is performed by effectively utilizing the entire width of the flat tubes 2. The heat-exchanged oil flows in the stacking direction through a pair of openings 25 and 28 at the other end, and finally merges into a single opening 25A to form a circle on the other mounting flange 3 serving as an oil outlet. It flows out from the opening 6.

  Therefore, in the above embodiment, the oil can be flowed in the form of expanding in the width direction of the flat tube 2 without complicating the configuration of the oil inlet or outlet connected to the oil cooler 1, and heat exchange Efficiency can be improved.

  Here, in the said Example, a pair of opening part 28 of the upper side plate 22 which opposes the single opening part 25A is non-circular, and a pair of opening parts 25 and 28 of the flat tube 2 after the 2nd step | stage. Has a similar non-circular shape. FIG. 8 shows a pair of openings 28 of the upper plate 22, and as shown in the figure, the opening edges 28 a of adjacent portions form a straight line along the longitudinal direction of the flat tube 2, and the flat tube 2. The opening edge 28b of the part which goes to the longitudinal direction center of this forms the linear form along the width direction of the flat tube 2. As shown in FIG. A corner portion 28c formed by these two linear portions 28a and 28b having an angle of 90 ° is rounded along an arc having a relatively small radius. In addition, the opening edge 28d of the remaining portion of the opening 28 has an arc shape with the straight opening edges 28a and 28b as tangents. In other words, each opening 28 has a basic shape of a circle centered on the point O1, and the above-described linear opening edges 28a and 28b extend as tangents to the circle, respectively.

  Then, in the flat tube 2 at the lowermost stage, when projected in the stacking direction, as shown in FIG. 10, the corner portion 28c constituted by the two linear portions 28a and 28b has the lower plate 21A. Are located within a single opening 25A. The opening 25A of the lower plate 21A has a circular shape centered on the point O2, and has an opening area larger than each opening area of the opening 28 of the upper plate 22. However, the sum total of the opening areas of the pair of openings 28 is larger than the opening area of the single opening 25A. Further, the center O1 of the basic circle of the pair of openings 28 is located on the outer side in the longitudinal direction of the flat tube 2 with respect to the center O2 of the circle of the opening 25A. In other words, as shown in FIG. 10, the opening 28 as a whole is located at a position shifted from the opening 25 </ b> A to the outside in the longitudinal direction of the flat tube 2. Thereby, the width direction center part of the edge part of the fin plate 23 is exposed in the opening part 25A.

  As described above, the corner portion 28c composed of the two linear portions 28a and 28b has a shape extending to the outer peripheral side from the basic circle as compared with the basic circle of the opening 28 with the point O1 as the center. Therefore, as a result of the corner portion 28c overlapping with the single opening portion 25A, a larger overlapping area between the opening portion 25A and the opening portion 28 can be obtained as compared with the case where the pair of opening portions 28 are formed into a simple circle. .

  On the other hand, an inter-port passage 40 is formed between the boss portions 29 constituting the pair of oil ports 37 having the openings 28 as described above, and this inter-port passage 40 is the main flow path of the cooling water. It has become one of the. If the diameter of the opening 28 or the boss 29 is set large and the inter-port passage 40 is narrowed, the flow in the cooling water passage 12 between the flat tubes 2 is deteriorated.

  According to the configuration of the corner portion 28c including the linear portions 28a and 28b as in the above-described embodiment, it is possible to enlarge the overlapping area with the opening 25A without narrowing the inter-port passage 40 at all.

  Moreover, in the said Example, the remaining opening edge 28d which does not overlap with the opening part 25A is circular arc shape, and the boss | hub part 29 surrounding this also becomes a cylindrical surface. Therefore, the flow of the cooling water flowing along the thin wall portion 38 becomes smooth, and a relatively large cooling water passage cross-sectional area viewed along the direction of the cooling water flow can be secured. If the opening 28 and the boss 29 are rectangular in plan view, the cooling water passage sectional area viewed along the direction of the cooling water flow is narrowed and the cooling water flow collides. When doing so, a smooth flow cannot be obtained.

  Further, in the above embodiment, since the end of the fin plate 23 is located adjacent to the linear portion 28b of the opening 28, the size of the fin plate 23 that provides a substantial heat exchange area can be ensured to the maximum. This is advantageous in terms of heat exchange efficiency. Moreover, the fin plate 23 can be made into a simple rectangular shape, and processing and formation become easy.

  Moreover, since the center O1 of the basic circle of the pair of openings 28 is located on the outer side in the longitudinal direction of the flat tube 2 with respect to the center O2 of the circle of the single opening 25A, the position of the mounting flange 3 (in other words, For example, the size of the fin plate 23 can be ensured larger than the outer dimension of the oil cooler 1.

  Moreover, in the said Example, the substantially triangular space which followed the rectangular space in the fin plate accommodating part 30 is formed in the inside of the flat tube 2 by the port side guide wall 29a and the extension part 30b which comprise the nozzle part 42. FIG. . As a result, for example, on the oil inlet side, an oil passage that gradually expands in the width direction from the internal space of the oil port 37 (boss portion 29) toward the end face of the fin plate 23 is configured, and the passage resistance of the oil is reduced. In addition, the flow distribution can be made uniform.

  As mentioned above, although one Example of this invention was described in detail based on drawing, this invention is not limited to the said Example, A various change is possible. For example, in the present invention, the shape of the boss portion 29 and the presence or absence of the guide wall 34 are arbitrary. Moreover, it can apply not only to an oil cooler but to various heat exchangers.

DESCRIPTION OF SYMBOLS 1 ... Oil cooler 2 ... Flat tube 3 ... Mounting flange 10 ... Case 11 ... Oil flow path 12 ... Cooling water flow path 21 ... Lower plate 22 ... Upper plate 23 ... Fin plate 25, 25A ... Opening 28 ... Opening 29 ... Boss part 34 ... Guide wall 36 ... Emboss 37 ... Oil port

Claims (4)

A heat exchanger in which a flat tube whose inside is a flow path of a first fluid is stacked in a plurality of stages through a gap which is a flow path of a second fluid, and each flat tube is mutually connected at the periphery The first and second plates joined together, and the fin plate sandwiched between the first and second plates, and two adjacent flat tubes are one flat tube. The opening provided at each end in the longitudinal direction of the second plate and the opening provided at each end in the longitudinal direction of the first plate of the other flat tube are joined together. In the heat exchanger in which the first fluid flows in the longitudinal direction of each flat tube through these openings,
At each end in the longitudinal direction of the first plate in the lowermost flat tube, a single opening serving as a fluid inlet or a fluid outlet of the heat exchanger is formed as the opening.
At each end in the longitudinal direction of the second plate combined with the first plate, as the opening, a pair of openings are arranged side by side in the width direction of the flat tube,
The pair of openings in the second plate are such that the opening edges of the adjacent portions form a straight line along the longitudinal direction of the flat tube, and the opening edges of the portion toward the longitudinal center of the flat tube are A straight portion along the width direction is formed, and a corner portion constituted by these two straight portions is located in a single opening of the first plate when projected in the stacking direction . Heat exchanger.   The heat exchanger according to claim 1, wherein the remaining part of the pair of openings is circular.   The heat exchange according to claim 1 or 2, wherein an end portion of the fin plate in a longitudinal direction forms a straight line along a width direction of the flat tube and is located along an opening edge of the pair of openings. vessel.   The heat exchanger according to any one of claims 1 to 3, wherein the second and subsequent flat tubes include a pair of openings at each end corresponding to the second plate of the lowermost flat tube. .

Images