heat exchanger

Abstract

To improve heat exchange performance of a heat exchanger.SOLUTION: A heat exchanging part 30 has a plate 31 where recesses 31a provided inside a flow path formation part 32 face each other to form a flow path part 33. The flow path part 33 is disposed offset so that it does not overlap in a lamination direction the flow path part 33 of another heat exchanging part 30 adjacent in the lamination direction. The flow path formation part 32 has a flow path expansion part 41 whose height H in the lamination direction is larger than 1 / 2 pitch P of the heat exchanging part 30 adjacent in the lamination direction. In an offset direction of the flow path part 33, length L2 of a joint 31c where each of a pair of plates 31 is joined is smaller than length of projections 31b on the opposite surface of the recesses 31a forming the flow path part 33, and a flow path cross-sectional area of lubricating-oil between the joint 31c and an apex of the flow path expansion part 41 is smallest at a position where the flow path expansion part 41 is installed. The lubricating-oil circulates among a plurality of heat exchanging parts 30 so as to cross outside a plurality of flow path expansion parts 41.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a heat exchanger. [Background technology]

[0002] Patent document 1 discloses a heat exchanger in which multiple embossments are formed in areas of a heat exchange element where no communicating flow paths are formed, so that the communicating flow paths abut the adjacent heat exchange elements, thereby maintaining the spacing between the adjacent heat exchange elements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-151392 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the heat exchanger described in Patent Document 1, there are many portions in the heat exchange member where no communicating flow passages are formed, which may result in reduced heat exchange performance.

[0005] The present invention has been made in consideration of the above problems, and has an object to improve the heat exchange performance of a heat exchanger. [Means for solving the problem]

[0006] According to one aspect of the present invention, a heat exchanger includes a pair of header tanks and a plurality of heat exchange units stacked in a stacking direction, each having a flow path forming portion forming a flow path portion therein through which a first fluid flows, and exchanging heat with a second fluid flowing outside, wherein each of the heat exchange units has a pair of plates stacked in the stacking direction such that recesses provided inside the flow path forming portion face each other to form the flow path portion, and the flow path portion is offset in the stacking direction so as not to overlap with the flow path portion of another heat exchange unit adjacent in the stacking direction, The forming portion has a flow path expansion portion whose height in the stacking direction is greater than 1 / 2 the pitch of adjacent heat exchange portions in the stacking direction, and in the offset direction in which the flow path portions are offset, the length of the joint portion where the pair of plates are joined to each other is shorter than the length of the convex portion on the opposite side of the concave portion that forms the flow path portion, and at the position where the flow path expansion portion is provided, the flow path cross-sectional area of ​​the second fluid between the joint portion and the top of the flow path expansion portion is smallest, and the second fluid circulates between the multiple heat exchange portions so as to cross the outside of the multiple flow path expansion portions. [Effects of the Invention]

[0007] In the above embodiment, the flow path section through which the first fluid flows in the heat exchange section is offset from the flow path section of another heat exchange section adjacent to the heat exchange section in the stacking direction so as not to overlap in the stacking direction, and the flow path forming section has an expanded flow path section whose height in the stacking direction is greater than half the pitch of the heat exchange sections adjacent to the heat exchange section in the stacking direction. Therefore, in the area where the expanded flow path section is provided, the heat exchange area is increased by the size of the expanded flow path section, and the flow path of the second fluid is narrowed, thereby increasing the flow rate of the second fluid. This increases the amount of heat exchange between the first fluid flowing through the flow path section inside the expanded flow path section and the second fluid flowing outside. This improves the heat exchange performance of the heat exchanger. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an external perspective view of a heat exchanger according to an embodiment of the present invention, viewed obliquely from above. [Figure 2]FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, illustrating the first bypass prevention member on the bottom surface of the heat exchanger. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1, illustrating the second bypass prevention member on the side surface of the heat exchanger. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1, and is a perspective view showing one of the plates. [Figure 5] FIG. 5 is a diagram showing a cross section of the heat exchanger taken along line VV in FIG. [Figure 6] FIG. 6 is a cross-sectional view of the heat exchanger taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a configuration diagram illustrating a modified example of the state in which the heat exchanger is attached to the vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0009] A heat exchanger 100 according to an embodiment of the present invention will be described below with reference to the drawings.

[0010] First, the overall configuration of the heat exchanger 100 will be described with reference to FIGS.

[0011] Fig. 1 is an external perspective view of the heat exchanger 100 seen from diagonally above. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1, illustrating the first bypass prevention member 13 on the bottom surface of the heat exchanger 100. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1, illustrating the second bypass prevention member 14 on the side surface of the heat exchanger 100.

[0012] 1, the heat exchanger 100 is mounted on a vehicle 1. Specifically, the heat exchanger 100 cools lubricating oil for lubricating and cooling a power transmission device 2 mounted on the vehicle 1 by exchanging heat with cooling water circulating outside. The heat exchanger 100 is a so-called microtube heat exchanger, which will be described later, with a flow path height of 1.0 mm or less.

[0013] The power transmission device 2 is, for example, a transmission that changes the speed and transmits power from a drive source, or an electric drive device that has an electric motor and a reducer, etc. Here, the cooling water corresponds to the first fluid, and the lubricating oil corresponds to the second fluid.

[0014] The power transmission device 2 is provided with a mounting portion 3 formed in a recessed shape. A heat exchanger 100 is inserted into the mounting portion 3. The mounting portion 3 has a side portion 3a and a bottom portion 3b (see FIGS. 2 and 3). The side portion 3a has an inlet 3c through which lubricating oil flows in, and an outlet (not shown) through which the lubricating oil flows out after passing through the heat exchanger 100. The lubricating oil flows through the mounting portion 3 so as to pass linearly through the heat exchanger 100 attached to the mounting portion 3.

[0015] The heat exchanger 100 comprises a core 10, a cover member 11 as a first end member, a bottom plate 12 as a second end member (see Figures 2 and 3), a first bypass prevention member 13 (see Figure 2), and a second bypass prevention member 14 (see Figure 3).

[0016] The core section 10 has a pair of header tanks 20 and multiple heat exchange sections 30. The core section 10 exchanges heat between the lubricating oil and the cooling water flowing in a direction intersecting (here, substantially perpendicular to) the lubricating oil. A first bypass prevention member 13 is provided on the bottom surface of the core section 10. A second bypass prevention member 14 is provided on the side surface of the core section 10.

[0017] The core 10 is arranged so that the heat exchange section 30 is provided on the flow path between the inlet 3c and the outlet through which the lubricating oil flows, and the header tank 20 is provided at a position away from the flow path between the inlet 3c and the outlet. This increases the flow rate of the lubricating oil flowing through the heat exchange section 30, thereby improving the heat exchange performance of the heat exchanger 100.

[0018] Hereinafter, the direction in which the plates 31 (see Figure 2) constituting the multiple heat exchange sections 30 are stacked will be referred to as the "stacking direction," the direction in which the cooling water flows within the heat exchange section 30 will be referred to as the "cooling water flow direction," and the direction in which the lubricating oil flows between adjacent heat exchange sections 30, which is a direction that intersects the flow direction (here, approximately perpendicular), will be referred to as the "lubricating oil flow direction" or "offset direction."

[0019] The header tanks 20 are provided upstream and downstream in the cooling water flow direction of the core section 10. One of the header tanks 20, provided upstream of the core section 10, is connected to a cooling water inlet 11a. The other header tank 20, provided downstream of the core section 10, is connected to a cooling water outlet 11b.

[0020] As shown in FIG. 2, a plurality of heat exchange units 30 are provided, stacked at equal intervals (equal pitch) in the stacking direction. Each heat exchange unit 30 has a pair of plates 31 stacked in the stacking direction. The heat exchange unit 30 has a flow path forming portion 32 (see FIG. 4) that forms a flow path portion 33 therein through which cooling water flows. The heat exchange unit 30 exchanges heat with the lubricating oil flowing outside. The specific configuration of the heat exchange unit 30 will be described in detail later with reference to FIGS. 4 to 6.

[0021] The lid member 11 is attached to one end of the core portion 10 in the stacking direction. The lid member 11 secures the core portion 10 from one end. The lid member 11 is attached to the power transmission device 2 so as to sandwich a sealing member (not shown). The lid member 11 closes the space between the mounting portion 3 of the power transmission device 2 and the outside. A cooling water inlet 11a that allows cooling water to flow into the core portion 10 and a cooling water outlet 11b that allows cooling water to flow out from inside the core portion 10 are connected to the lid member 11.

[0022] 1, the cooling water inlet 11a is a pipe for introducing cooling water into the core section 10. The cooling water inlet 11a is connected to the cover member 11, and allows cooling water flowing from the outside to flow into the core section 10. The cooling water that flows into the core section 10 from the cooling water inlet 11a flows through the header tank 20 so as to spread throughout the entire flow path section 33 (described later) in the core section 10.

[0023] The cooling water outlet 11b is a pipe for discharging the cooling water from the core portion 10. The cooling water outlet 11b is connected to the cover member 11, and causes the cooling water that has flowed through each flow path portion 33 to flow out to the outside via the header tank 20.

[0024] As shown in FIG. 2, the bottom plate 12 is attached to the other end of the core unit 10 in the stacking direction. The bottom plate 12 fixes the core unit 10 from the other end. The bottom plate 12 separates the lubricating oil flowing through the power transmission device 2 from the cooling water flowing through the core unit 10 to prevent them from mixing. A first bypass prevention member 13 is provided on the bottom plate 12.

[0025] The first bypass prevention member 13 is a sealing plate that is installed at an angle to the lubricating oil flow direction. The first bypass prevention member 13 is a flat plate made of metal such as an aluminum alloy. Specifically, the first bypass prevention member 13 is installed so that the more upstream in the lubricating oil flow direction the first bypass prevention member 13 is, the farther away from the bottom plate 12 in the stacking direction. The upstream end of the first bypass prevention member 13 is fixed to the bottom plate 12 by brazing or the like.

[0026] When the first bypass prevention member 13 is attached to the attachment portion 3, its upstream end in the lubricating oil flow direction abuts against the bottom surface portion 3b, and the first bypass prevention member 13 is deformed to reduce the inclination angle with respect to the bottom plate 12. As a result, the first bypass prevention member 13 is fixed in a state where it is pressed against the bottom surface portion 3b.

[0027] The first bypass prevention member 13 blocks the flow of lubricating oil to prevent a bypass flow from occurring, in which the lubricating oil flows downstream between the core portion 10 and the bottom surface portion 3b without passing through the core portion 10 from upstream in the lubricating oil flow direction. As the lubricating oil flows through the first bypass prevention member 13, the lubricating oil hits the inclined surface and is further pressed against the bottom surface portion 3b. Therefore, the first bypass prevention member 13 can improve sealing performance by utilizing the flow of the lubricating oil.

[0028] 3, the second bypass prevention member 14 is a comb-shaped member attached to the side surface of the core unit 10. The second bypass prevention member 14 is a flat plate made of metal such as an aluminum alloy. The second bypass prevention member 14 is integrally formed by brazing or the like while attached to the core unit 10.

[0029] The second bypass prevention member 14 has a seal portion 14a and multiple insertion portions 14b. The seal portion 14a is inserted between the side end surface of the core portion 10 and the side surface portion 3a of the mounting portion 3 to fill the gap. The insertion portions 14b are inserted between adjacent heat exchange units 30 in the stacking direction to fill the gap. The insertion portions 14b are also inserted between the heat exchange unit 30 at one end in the stacking direction and the cover member 11, and between the heat exchange unit 30 at the other end in the stacking direction and the bottom plate 12 to fill the gap.

[0030] The second bypass prevention member 14 blocks the flow of lubricating oil to prevent a bypass flow from occurring, in which the lubricating oil flows downstream between the core portion 10 and the side surface portion 3a without passing through the core portion 10 from upstream in the lubricating oil flow direction. The second bypass prevention member 14 is provided at each end of the first bypass prevention member 13 in the cooling water flow direction. This allows the first bypass prevention member 13 and the second bypass prevention member 14 to prevent the occurrence of a bypass flow of the lubricating oil.

[0031] Next, a specific configuration of the heat exchange section 30 will be described with reference to FIGS.

[0032] Fig. 4 is a view corresponding to a cross section taken along line IV-IV in Fig. 1, and is a perspective view showing one of the plurality of plates 31. Fig. 5 is a view showing a cross section of the heat exchanger 30 taken along line VV in Fig. 4. Fig. 6 is a view showing a cross section of the heat exchanger 30 taken along line VI-VI in Fig. 4. Note that Fig. 4 only shows the vicinity of one header tank 20 on the upstream side in the cooling water flow direction, but the vicinity of the other header tank 20 on the downstream side in the cooling water flow direction is configured in the same way.

[0033] As shown in Fig. 4, the heat exchange section 30 has a flow path forming section 32. As shown in Fig. 5 and Fig. 6, the heat exchange section 30 has a pair of plates 31 stacked in the stacking direction.

[0034] The plates 31 are stacked in the stacking direction to integrally form the header tank 20 and the heat exchange section 30. This allows the header tank 20 and the heat exchange section 30 to be integrally formed simply by stacking and brazing the plates 31, thereby reducing the manufacturing cost of the heat exchanger 100.

[0035] The plates 31 constituting the same heat exchange section 30 are stacked in opposite stacking directions. The pair of plates 31 are formed to have shapes that are plane-symmetrical with respect to their mating surfaces. In this case, the pair of plates 31 may be formed to have the same shape. In this case, the manufacturing cost of the heat exchanger 100 can be reduced. The pair of plates 31 may have the same shape only for the flow path forming sections 32, and the positions of the header tanks 20 may be different. In other words, it is sufficient that the plates 31 constituting the same heat exchange section 30 have at least the same shape for the flow path forming sections 32.

[0036] The flow path forming portion 32 forms a flow path portion 33 inside thereof through which the cooling water flows. The flow path forming portion 32 has a plurality of straight flow path portions 40 and a plurality of communication flow paths 50.

[0037] The height (channel height) of the flow path section 33 in the stacking direction is 1.0 mm or less. Specifically, the channel height He (see FIG. 6) of the channel expansion section 41, which has the greatest channel height in the flow path section 33, is 1.0 mm or less. In other words, the heat exchanger 100 is a so-called microtube heat exchanger.

[0038] 6, the flow path portion 33 is arranged offset in the stacking direction from the flow path portion 33 of another heat exchanger 30 adjacent to it in the stacking direction so as not to overlap with it in the stacking direction. Specifically, the flow path portion 33 is arranged offset in the lubricating oil flow direction from the flow path portion 33 of another heat exchanger 30 adjacent to it in the stacking direction.

[0039] 4, the straight flow path section 40 is a flow path through which cooling water flows linearly. The flow path height at the position where the straight flow path section 40 intersects with a communication flow path 50 (described later) is the same as the flow path height at other parts of the communication flow path 50. The straight flow path section 40 has a flow path expansion section 41, a transition section 42, and a throttle section 43.

[0040] 6, the height H [mm] of the expanded flow path section 41 in the stacking direction is greater than ½ [mm] of the pitch P between adjacent heat exchange sections 30 in the stacking direction. This increases the flow path height of the flow path section 33 in the expanded flow path section 41. Therefore, even when the heat exchanger 100 is a microtube heat exchanger, clogging of the cooling water flow path section 33 during brazing can be suppressed.

[0041] Generally, microtube heat exchangers are manufactured by arranging thin tubes with a diameter of 1.0 mm or less at intervals. In contrast, in heat exchanger 100, the lubricating oil flow path is only partially narrowed at the position where enlarged flow path section 41 is provided, so by simply managing the dimensions at this position, it can be manufactured in the same way as a normal heat exchanger that is not a microtube heat exchanger.

[0042] The lubricating oil flows between the multiple heat exchange sections 30 so as to cross the outside of the multiple enlarged flow path sections 41. The cross-sectional area of ​​the lubricating oil flow path is smallest where the enlarged flow path sections 41 are provided. In the area where the enlarged flow path sections 41 are provided, the heat exchange area increases by the size of the enlarged flow path sections 41, and the smaller cross-sectional area of ​​the lubricating oil flow path increases the flow rate of the lubricating oil.

[0043] In this way, the flow path section 33 through which the coolant flows in the heat exchange section 30 is offset so as not to overlap with the flow path section 33 of another heat exchange section 30 adjacent in the stacking direction, and the expanded flow path section 41 has a height H [mm] in the stacking direction that is greater than 1 / 2 [mm] of the pitch P between adjacent heat exchange sections 30 in the stacking direction (H>P / 2). That is, the inclined surfaces of convex sections 31b (described later) of the expanded flow path sections 41 provided in each of adjacent heat exchange sections 30 overlap in the lubricating oil flow direction.

[0044] Therefore, in the portion where the expanded flow path section 41 is provided, the heat exchange area is increased by the size of the expanded flow path section 41, and the flow rate of the lubricating oil increases as the lubricating oil flow path becomes narrower. This increases the amount of heat exchanged between the cooling water flowing through the flow path section 33 inside the expanded flow path section 41 and the lubricating oil flowing outside. This improves the heat exchange performance of the heat exchanger 100.

[0045] The transition section 42 gradually changes the height of the flow path section 33 to the height of the flow path expansion section 41. Specifically, the transition section 42 is formed obliquely in the cooling water flow direction, and gradually changes the flow path cross-sectional area of ​​the straight flow path section 40. The transition section 42 is inclined so as to change linearly from the height H [mm] of the flow path expansion section 41 to the height P / 2 [mm] of the communicating flow path 50 downstream of the flow path expansion section 41. On the other hand, the transition section 42 is inclined so as to change linearly from the height P / 2 [mm] of the communicating flow path 50 to the height H [mm] of the flow path expansion section 41 upstream of the flow path expansion section 41.

[0046] By providing the transition sections 42 on both the upstream and downstream sides of the enlarged flow path section 41, the change in the flow path cross-sectional area in the flow path section 33 can be made gentler, and abrupt changes in the flow path cross-sectional area can be prevented.

[0047] The throttle section 43 is provided at the connection portion with the header tank 20. The throttle section 43 has a smaller flow path cross-sectional area than other portions of the flow path section 33. Specifically, the throttle section 43 is formed obliquely in the cooling water flow direction, and gradually changes the flow path cross-sectional area in the straight flow path section 40. The throttle section 43 is inclined so as to change linearly from the height P / 2 [mm] of the communicating flow path 50 to the height H [mm] of the flow path expansion section 41 downstream of the header tank 20. On the other hand, the transition section 42 is inclined so as to change linearly from the height H [mm] of the flow path expansion section 41 to the height P / 2 [mm] of the communicating flow path 50 downstream of the flow path expansion section 41.

[0048] The provision of the throttle section 43 makes it possible to gently change the cross-sectional area of ​​the flow path in the flow path section 33 and prevent a sudden change in the cross-sectional area of ​​the flow path. In addition, the flow velocity of the cooling water changes when the cooling water passes through the throttle section 43, which has the effect of disturbing the flow of the cooling water.

[0049] The communicating flow paths 50 communicate adjacent straight flow path sections 40 to allow cooling water to flow between them. The flow path height of the communicating flow paths 50 is P / 2 [mm]. That is, the entire communicating flow paths 50, including the positions where they intersect with the straight flow path sections 40, are formed to have the same flow path height.

[0050] By providing the communicating flow paths 50, the coolant is guided from the straight flow path portion 40 with a high coolant pressure to the straight flow path portion 40 with a low coolant pressure, and the flow rate of the coolant can be made uniform in the multiple straight flow path portions 40. This prevents a decrease in the heat exchange performance in some of the straight flow path portions 40, and improves the heat exchange performance of the entire heat exchanger 100.

[0051] Furthermore, the protrusions 50a of the communication channels 50 of the plates 31 adjacent in the stacking direction are in contact with each other in the stacked state and are joined by brazing (not shown), thereby ensuring an appropriate gap dimension in the stacking direction between the plates 31 that form the lubricating oil channels.

[0052] The pair of plates 31 constituting the heat exchange unit 30 have recesses 31a formed inside the flow path forming portion 32 facing each other to form a flow path portion 33. The plates 31 have recesses 31a, protrusions 31b, and joint portions 31c.

[0053] The recess 31a is formed in a concave shape on one of the flat surfaces by pressing the plate 31.

[0054] The protrusion 31b is formed in a protruding shape on the other flat surface by press working the plate 31. A recess 31a is formed on the back surface of the protrusion 31b.

[0055] The joint portion 31c is formed continuously from the enlarged flow path portion 41 formed by the recessed portion 31a and the protruding portion 31b. The joint portion 31c is a flat portion for joining a pair of plates 31 that constitute the same heat exchange portion 30. The joint portions 31c of the pair of plates 31 that constitute the heat exchange portion 30 are joined together by brazing.

[0056] In the offset direction (lubricant flow direction) in which the flow path sections 33 are offset, the length L2 [mm] of the joint section 31c where the pair of plates 31 are joined together is smaller than the length L1 [mm] of the convex section 31b on the surface opposite to the concave section 31a that forms the expanded flow path section 41 (L1>L2). That is, the inclined surfaces of the convex sections 31b of the expanded flow path sections 41 provided in adjacent heat exchange sections 30 overlap in the stacking direction.

[0057] This allows the heat exchange performance of the entire heat exchanger 100 to be improved by increasing the length L1 of the convex portion 31b that constitutes the flow path expansion section 41, which contributes to improving the heat exchange performance, and by decreasing the length L2 of the joint portion 31c, which contributes little to improving the heat exchange performance.

[0058] The angle α [deg] of the plate 31 inclined from the joint 31c toward the enlarged flow path portion 41 is an acute angle.

[0059] By setting the angle α at which the plate 31 is inclined to an acute angle, the change in the flow path cross-sectional area in the flow path portion 33 is made gentler, and a sudden change in the flow path cross-sectional area can be prevented, thereby suppressing the generation of turbulence in the cooling water.

[0060] Next, a modified example of the state in which the heat exchanger 100 is attached to the vehicle 1 will be described with reference to FIG.

[0061] FIG. 7 is a configuration diagram illustrating a modified example of the state in which the heat exchanger 100 is attached to the vehicle 1. In FIG.

[0062] As shown in FIG. 7, the mounting portion 3 provided on the power transmission device 2 is provided at an angle to the flow of lubricating oil.

[0063] The core 10 is arranged such that the heat exchange section 30 is provided on the flow path between the inlet 3c and the outlet 3d through which the lubricating oil flows, and the header tank 20 is provided at a position away from the flow path between the inlet 3c and the outlet 3d. This increases the flow rate of the lubricating oil flowing through the heat exchange section 30, thereby improving the heat exchange performance of the heat exchanger 100.

[0064] The mounting portion 3 has a plurality of folded portions 5 at positions away from the flow path between the inlet 3c and the outlet 3d, thereby preventing the occurrence of a bypass flow in which the lubricating oil flows downstream from upstream without passing through the core portion 10 of the heat exchanger 100.

[0065] According to the above embodiment, the following effects are achieved.

[0066] The heat exchanger 100 comprises a pair of header tanks 20 and a plurality of heat exchange sections 30 stacked in the stacking direction, each having a flow path forming section 32 that forms a flow path section 33 inside through which cooling water flows, and performing heat exchange with lubricating oil flowing outside, and each heat exchange section 30 has a pair of plates 31 stacked in the stacking direction so that recesses 31a provided on the inside of the flow path forming section 32 face each other to form the flow path section 33, and the flow path section 33 is offset in the stacking direction so as not to overlap with the flow path section 33 of another heat exchange section 30 adjacent in the stacking direction, and the flow path forming section 32 has a flow path expansion section 41 whose height H [mm] in the stacking direction is greater than 1 / 2 (P / 2 [mm]) of the pitch P [mm] between adjacent heat exchange sections 30 in the stacking direction.

[0067] According to this configuration, the flow passages 33 through which the coolant flows in the heat exchanger 30 are offset from the flow passages 33 of adjacent heat exchangers 30 in the stacking direction so as not to overlap with the flow passages 33 of adjacent heat exchangers 30 in the stacking direction. The expanded flow passages 41 have a height H [mm] in the stacking direction that is greater than half the pitch P [mm] between adjacent heat exchangers 30 in the stacking direction (H > P / 2). Therefore, in the area where the expanded flow passages 41 are provided, the heat exchange area is increased by the size of the expanded flow passages 41, narrowing the lubricating oil flow passage and increasing the flow rate of the lubricating oil. This increases the amount of heat exchanged between the coolant flowing through the flow passages 33 inside the expanded flow passages 41 and the lubricating oil flowing outside. This improves the heat exchange performance of the heat exchanger 100.

[0068] The flow path forming portion 32 further includes a transition portion 42 that gradually changes the height of the flow path portion 33 to the height of the flow path enlarged portion 41 .

[0069] According to this configuration, the provision of the transition section 42 makes it possible to make the change in the flow path cross-sectional area of ​​the flow path section 33 gentler, thereby preventing the flow path cross-sectional area from changing suddenly.

[0070] The flow path forming portion 32 also has a throttle portion 43 at the connection portion with the header tank 20, the flow path cross-sectional area of ​​which is smaller than that of the other portion of the flow path portion 33.

[0071] According to this configuration, the flow rate of the cooling water changes when the cooling water passes through the throttle portion 43, which has the effect of disturbing the flow of the cooling water.

[0072] In addition, in the offset direction (lubricant flow direction) in which the flow path section 33 is offset, the length L2 [mm] of the joint 31c where the pair of plates 31 are joined to each other is smaller than the length L1 [mm] of the convex portion 31b on the opposite side of the concave portion 31a that forms the flow path section 33 (L1>L2).

[0073] According to this configuration, the heat exchange performance of the entire heat exchanger 100 can be improved by increasing the length L1 of the convex portion 31b that constitutes the flow path expansion portion 41, which contributes to improving the heat exchange performance, and by decreasing the length L2 of the joint portion 31c, which does not contribute to improving the heat exchange performance.

[0074] Furthermore, at the position where the enlarged flow path portion 41 is provided, the cross-sectional area of ​​the flow path for the lubricating oil is minimum.

[0075] According to this configuration, in the portion where the enlarged flow path section 41 is provided, the heat exchange area is increased by the size of the enlarged flow path section 41, and the flow rate of the lubricating oil increases as the cross-sectional area of ​​the lubricating oil flow path decreases.

[0076] The angle α [deg] of the plate 31 inclined from the joint 31c toward the enlarged flow path portion 41 is an acute angle.

[0077] According to this configuration, by setting the angle α at which the plate 31 is inclined to an acute angle, the change in the flow path cross-sectional area in the flow path portion 33 is gradual, and a sudden change in the flow path cross-sectional area can be prevented, thereby suppressing the generation of turbulence in the cooling water.

[0078] In addition, the flow path forming section 32 has a plurality of straight flow path sections 40 having flow path expansion sections 41 through which cooling water flows linearly, and a communicating flow path 50 that connects adjacent straight flow path sections 40 so that cooling water can flow between them, and the flow path height (P / 2) at the position where the straight flow path section 40 intersects with the communicating flow path 50 is the same as the flow path height (P / 2) at other parts of the communicating flow path 50.

[0079] According to this configuration, the provision of the communicating flow paths 50 allows the coolant to be guided from the straight flow path portion 40 with a high coolant pressure to the straight flow path portion 40 with a low coolant pressure, thereby making the flow rate of the coolant uniform in the multiple straight flow path portions 40. This prevents a decrease in the heat exchange performance in some of the straight flow path portions 40, and improves the heat exchange performance of the entire heat exchanger 100.

[0080] Furthermore, the lubricating oil flows between the plurality of heat exchange sections 30 so as to cross the outside of the plurality of enlarged flow path sections 41 .

[0081] With this configuration, when the lubricating oil flows between the heat exchange sections 30, it passes through the outside of the expanded flow path sections 41. This increases the heat exchange area by the size of the expanded flow path sections 41, narrowing the lubricating oil flow path and increasing the flow rate of the lubricating oil. This improves the heat exchange performance of the heat exchanger 100.

[0082] The plates 31 are stacked in the stacking direction to integrally form the header tank 20 and the heat exchange section 30 .

[0083] According to this configuration, the header tank 20 and the heat exchange section 30 can be integrally formed simply by stacking and brazing the plates 31, so that the manufacturing cost of the heat exchanger 100 can be reduced.

[0084] Furthermore, the protrusions 50a of the communication channels 50 on the plates 31 adjacent to each other in the stacking direction are joined to each other.

[0085] This configuration makes it possible to ensure an appropriate gap dimension in the stacking direction between the plates 31 that form the flow path of the lubricating oil.

[0086] The first fluid is cooling water, and the second fluid is lubricating oil.

[0087] According to this configuration, when the lubricating oil for lubricating and cooling the power transmission device 2 of the vehicle 1 is cooled by the cooling water, it is possible to improve the heat exchange performance.

[0088] The height of the flow path section 33 in the stacking direction is 1.0 mm or less.

[0089] According to this configuration, when the heat exchanger 100 is a so-called microtube heat exchanger, the heat exchange performance can be improved.

[0090] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. [Explanation of symbols]

[0091] 100 heat exchanger 1 vehicle 2. Power transmission device 20 Header Tank 30 Heat exchange section 31 Plate 31a Recess 31b Convex part 31c joint 32 Flow path forming section 33 Flow path section 40 Straight flow path section 41 Flow path expansion section 42 Transition part 43 Constriction section 50 Connecting flow path

Claims

1. 1. A heat exchanger comprising: A pair of header tanks; a plurality of heat exchange units stacked in a stacking direction, each having a flow path forming portion forming a flow path portion therein through which a first fluid flows, and performing heat exchange with a second fluid flowing outside; Equipped with Each of the heat exchange units has a pair of plates stacked in the stacking direction so that recesses formed inside the flow path forming unit face each other to form the flow path unit, the flow path portion is offset in the stacking direction so as not to overlap with the flow path portion of another heat exchanger adjacent to the heat exchanger in the stacking direction, the flow path forming portion has a flow path expansion portion whose height in the stacking direction is greater than half the pitch of the heat exchange portions adjacent to each other in the stacking direction, In an offset direction in which the flow path portion is offset, a length of a joint portion where the pair of plates are joined to each other is shorter than a length of a convex portion on a surface opposite to the concave portion that forms the flow path portion, a cross-sectional area of ​​a flow path for the second fluid between the junction and a top of the flow path enlargement portion is minimum at a position where the flow path enlargement portion is provided; the second fluid flows between the plurality of heat exchange sections so as to cross the exteriors of the plurality of enlarged flow path sections; heat exchanger.

2. 2. The heat exchanger of claim 1, The flow path forming portion is a plurality of straight flow path portions each having the enlarged flow path portion and through which the first fluid flows linearly; a communication flow path that connects adjacent straight flow path portions to each other so that a first fluid can flow therethrough; and a flow path height at a position where the straight flow path section intersects with the communicating flow path is the same as a flow path height at other portions of the communicating flow path; heat exchanger.

3. 3. The heat exchanger according to claim 2, The convex portions of the communication flow paths of the plates adjacent to each other in the stacking direction are joined to each other. heat exchanger.

4. 4. A heat exchanger according to any one of claims 1 to 3, The first fluid is cooling water and the second fluid is lubricating oil. heat exchanger.

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