Core structure of housingless-type oil cooler
A housingless-type oil cooler includes cooling elements having first and second plates coupled with together, an oil return tube vertically arranged through a core portion, and a heat-transfer suppressing means. The cooling elements are piled up in a vertical direction of the core portion to alternately form cooling water chambers and oil chambers so that the adjacent cooling water chambers are fluidically connected through a cooling water passage and the adjacent oil chambers are fluidically connected through an oil passage. The oil return tube discharges oil introduced from one side of the core portion toward its other side through the oil chambers and the oil passages. The heat-transfer suppressing means is arranged between the oil chambers and the oil return tube to suppress heat transfer between the oil flowing in the oil chambers and the oil flowing in the oil return tube.
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1. Field of the Invention
The present invention relates to a core structure of a housingless-type oil cooler which has a plurality of plates piled up to form cooling water chambers and oil chambers therebetween without an additional housing so as to cool oil flowing through the oil chambers.
2. Description of the Related Art
Conventional oil coolers are used for and attached to, for example, automatic transmissions to cool oil thereof. Some of the conventional ones are constructed to have an oil tube forming an oil chamber and arranged in a cooling water chamber formed between a housing of the oil cooler and the oil tube. The other conventional ones are, what is called, a housingless-type oil cooler, which is constructed to have a plurality of plates to alternately form cooling water chambers and oil chambers therebetween for removing a housing, thereby decreasing its manufacturing costs and dimensions.
Specifically, such the housingless-type oil cooler has a core portion where a plurality of first plates and a plurality of second plates are piled up alternately with each other in a vertical direction of the core portion to alternately form cooling water chambers and oil chambers. The adjacent cooling water chambers are fluidically connected with each other through a cooling water passage, and the adjacent oil chambers are fluidically connected with each other through an oil passage. An oil return tube is provided to penetrate the core portion to allow oil to flow from the one side of the core portion toward the other side thereof. Such conventional oil coolers are disclosed in Japanese patents laid-open publication No. (Tokkaihei) 7-286786, No. (Tokkaihei) 11-351778, and No. 2002-277177.
The above known conventional core structures of the housingless-type oil coolers, however, encounter a problem in that coolability of the oil cooler deteriorates because the low-temperature oil, which is cooled by the cooling water in the cooling water chamber while it flows in the oil chambers, is reheated due to heat transfer from high-temperature oil in the oil chamber through a wall of the oil return tube while it flows through the oil return tube.
It is, therefore, an object of the present invention to provide a core structure of a housingless-type oil cooler which overcomes the foregoing drawbacks and can improve coolability of oil in the oil cooler.
SUMMARY OF THE INVENTIONAccording to a first aspect of the present invention there is provided a core structure of a housingless-type oil cooler including a plurality of first plates, a plurality of second plates, an oil return tube, and a heat-transfer suppressing means. The first plates are arranged alternately with the second plates so that the first plates and the second plates are piled up in a vertical direction of a core portion to alternately form cooling water chambers and oil chambers. The adjacent cooling water chambers are fluidically connected with each other through a cooling water passage, and the adjacent oil chambers are fluidically connected with each other through an oil passage. The oil return tube is arranged in the vertical direction through the core portion to discharge oil introduced from one side of the core portion toward the other side of the core portion through the oil chambers and the oil passages. The heat-transfer suppressing means is arranged between the oil chambers and the oil return tube to suppress heat transfer between the oil flowing in the oil chambers and the oil flowing in the oil return tube.
Therefore, the heat-transfer suppressing means suppresses the heat transfer from high-temperature oil in the oil chamber to the oil in the return oil tube through a wall of the oil return tube while it flows through the oil return tube. This can suppress rise in heat of the oil in the oil return tube and keep it be at the low temperature, thereby improving coolability of the oil cooler.
Preferably, the heat-transfer suppressing means is a heat-transfer suppressing chambers that are arranged between the oil chambers and the oil return tube and are fluidically connected with the cooling water chambers.
Therefore, the heat-transfer chambers suppress heat transfer between the oil flowing in the oil return tube and the oil flowing in the oil chambers, thereby improving coolability of the oil cooler. In addition, the cooling water in the heat-transfer cools the oil flowing through the oil return tube, further improving the coolability.
Preferably, the cooling water in the heat-transfer suppressing means is a heat-transfer suppressing chambers that are arranged between the oil chambers and the oil return tube and are filled with air.
Therefore, the air, having a low heat-transfer coefficient, in the heat-transfer chambers suppresses heat transfer between the oil flowing in the oil return tube and the oil flowing in the oil chambers, thereby improving coolability of the oil cooler.
BRIEF DESCRIPTION OF THE DRAWINGSThe objects, features and advantages of the present invention will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:
Throughout the following detailed description, similar reference characters and numbers refer to similar elements in all figures of the drawings, and their descriptions are omitted for eliminating duplication.
Referring to
The housingless-type oil cooler AA includes a core portion 1, an upper cover 4 covering a top portion of the core portion 1 sandwiched between an upper casing 2, a lower casing 3, and a oil return tube 6 fixed to the core portion and penetrating through a center axis thereof.
As shown in
The upper cover 4 is formed like a dish, and covers a top portion of the upper casing 2 to form an oil tank chamber 5 defined between the upper cover 4 and the upper casing 2. The upper cover 4 is formed at its center position with a fixing hole 4c in a circular cross-section, as shown in
As shown in
The lower casing 3 is formed like a disc, and is provided with an oil introducing port 3a at a position away from its center position, and also with a fixing hole 3b at the center position. The oil introducing port 3a is formed to have a circular cross-section, and fluidically communicates between the oil passage 16a and a not shown automatic transmission. The lower casing 3 is formed with an O-ring groove 3c, for receiving a not shown O ring, at its bottom surface so as to ensure a gap between the lower casing 3 and the automatic transmission to be liquid-tight when they are assembled with each other.
The oil return tube 6 is formed in a circular cylinder shape, and is inserted in the fixing holes 2b and 3b of the upper and lower casings 2 and 3, respectively, to be fixed to wall portions forming the fixing holes 2b and 3b so that its upper opening is located in the oil tank chamber 5 and its lower opening is located inside the automatic transmission.
On the other hand, as shown in
The core portion 1 is constructed so that a plurality of cooling elements are piled up in the vertical direction between the upper casing 2 and the lower casing 3. Each cooling elements has a first plate 11, a second plate 12 coupled with the first plate 11, and an inner fin 13 arranged between the first and second plates 11 and 12.
As shown in
In addition, as shown in
The second plate 12 is, as shown in
In addition, as shown in
The first to fifth cylindrical portions 12a to 12e of the second plate 12 are arranged to correspond with the first to fifth cylindrical portions 11a to 11e of the first plate 11, respectively.
The inner fin 13 is an offset fin in the first embodiment, but may be used another type one. The inner fin 13 is formed with first to fifth through-holes 13a to 13e corresponding to the first to fifth cylindrical portions 11a to 11e of the first plate 11 and to the first to fifth cylindrical portions 12a to 12e of the second plate 12.
The first plate 11 and the second plate 12 are coupled with each other, containing the inner fin 13 therein, to form an inner space therebetween for containing the inner fin 13, thereby forming the cooling element. The inner space forms an oil chamber 15 as shown in
The second and third cylindrical portions 11b and 11c of the first plate 11 and the second and third cylindrical portions of the next second plate 12 are fitted with each other, as shown in
On the other hand, the second plate 12 and its adjacent first plate 11 are also coupled with each other to form a cooling water chamber 17 therebetween as shown in
Incidentally, the second plate 12 is provided with a plurality of dimples 12f, four dimples 12f in the first embodiment, near the first cylindrical portion 12a on its bottom surface. The dimples 12f are not indispensable in the invention.
The second plate 12 and the next first plate 11 are kept predetermined-interval away from each other in the vertical direction by contacting the bending portion 14 with the bottom surface of the first plate 11 and connecting the dimples 12f with the upper surface of the next first plate 12.
As shown in
In addition, instead of the first plates 11 arranged at predetermined columns, the core portion 1 is provided between the adjacent first plates 11 with blocking-off plates 19, which has a blocking-off portion 19a at positions corresponding one of the second and third cylindrical portions 11b and 11c of the first plate 11. The block-off portions 19a contact on the upper surface of the next first plate 11 so that the first and second plates 11 and 12 are keep away from each other.
As shown in
The lower-most first plate 11 has no cylindrical portions, and is formed at its center position with a hole through which the oil return tube 6 can pass.
As shown in
Incidentally, each part of the housingless-type oil cooler AA is made of aluminum, and at least one side part of jointing parts is provided with a clad layer (a blazing sheet) thereon. Then, this temporarily assembled oil cooler AA is conveyed into a not-shown heating furnace to be heat-treated so as to be integrally formed by blazing the jointing parts. Thus assembled oil cooler AA is attached to the automatic transmission by using a bolt 9. The bolt 9 has a head to be pressed on an upper surface of the adapter member 10 at its top, and a screw portion 9a to be screwed into a screw hole of the automatic transmission at its bottom. The bolt 9 passes through a fixing hole 10a of the adapter member 10 and the oil return tube 6 in a state where there is formed a space as an oil return passage 6a for fluidically communicating the oil tank chamber 5 and a not-shown oil inlet port of the automatic transmission between the inner surface of the oil return tube 6 and the outer peripheral surface of the bolt 9.
Incidentally, the oil cooler AA may be attached to the automatic transmission by using bolts screwed into screw holes of flange portions radially projecting from the lower casing 3. In this case, the adapter member 10 is removed and the fixing hole 4c of the upper casing 4 is blocked off.
The operation of the housingless-type oil cooler AA having the core structure of the first embodiment will be described.
The cooling water is introduced into the cooling-water passage 18a through the cooling-water introducing pipe 7, and fills up each cooling-water chamber 17, then flowing out through the cooling-water passage 18b, where its flow direction is indicated by arrows in
On the other hand, high-temperature oil is introduced into the oil passage 16a through oil introducing port 3a, and then is changed its flow direction by the block-off plates 19, winding its way as indicated by arrows in
In the first embodiment, the oil flowing through the oil return tube 8 is prevented from receiving heat from the high temperature oil flowing in the oil passages 16a and 16b, because the heat-transfer suppressing chambers 20 filled with the cooling water are located therebetween to block off the heat transfer therebetween. This improves coolability of the oil cooler AA.
In addition, the cooling water in the heat-transfer suppressing chambers 20 cools the oil flowing through the oil return passage 6a, further improving the coolability of the oil cooler AA.
Next, a core structure of a housingless-type oil cooler of a second embodiment according to the present invention will be described with reference to the accompanying drawings.
As shown in
On the other hand, a second plate 12 has a first cylindrical portion 12a projecting downward, not having a bending portion like the first embodiment.
The first plate 11 and the second plate 12 are coupled with each other, containing an inner fin 13 therebetween, to form a cooling element. A plurality of the cooling elements are piled up in a vertical direction to form a core portion 1 of the oil cooler BB as shown in
In the assembled core portion 1, the bending portions 21 formed on the first cylindrical portions 11a of the first plates 1 and an outer surface of the oil return tube 6 are contacted with each other to form rooms as heat-transfer suppressing chambers 22 between the first cylindrical portions 11a and the outer surface of the oil return tube 6. The heat-transfer suppressing chambers 22 are arranged around the oil return tube 6 and are filled with the air for suppressing the heat transfer between the oil flowing in the oil return tube 6 and high-temperature oil flowing in oil chambers 15. The heat-transfer suppressing chamber 22 corresponds to a heat-transfer suppressing means of the present invention.
The other parts of the second embodiment are similar to those of the first embodiment, and their descriptions are omitted. The operation of the oil cooler BB having the core structure of the second embodiment is also similar to that of the first embodiment, and its description is omitted.
The air in the heat-transfer suppressing chambers 22 suppresses the heat transfer between the oil flowing in the oil return tube 6 and high-temperature oil flowing in oil chambers 15, because a heat transfer coefficient is low, thereby improving coolability of the oil cooler BB.
While there have been particularly shown and described with reference to preferred embodiments thereof, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.
The number of the cooling elements may be set arbitrarily, and positions and the numbers of the block-off plates 19 may be set arbitrarily according to need.
The heat-transfer chambers 22 filled with the air are formed by inwardly bending a peripheral portion of the end portion of the first cylindrical portion 11a formed on the first plate 11 to contact the peripheral portion on the outer surface of the oil return tube 6 in the second embodiment. Instead of the bending portion 21 of the first cylindrical portion 11a, as shown in
Instead of the annular projecting portion 23, as shown in
As described above, configurations of the first and second plates 11 and 12 and the oil return tube 6 may be set arbitrarily as long as they can form a heat-transfer suppressing chamber.
The entire contents of Japanese Patent Application No. 2005-343871 filed Nov. 29, 2005 are incorporated herein by reference.
Claims
1. A core structure of a housingless-type oil cooler comprising:
- a plurality of cooling elements, each of the cooling elements including a first plate and a second plate that are coupled with each other, the cooling elements being piled up in a vertical direction of a core portion to alternately form cooling water chambers and oil chambers so that the adjacent cooling water chambers are fluidically connected with each other through a cooling water passage and the adjacent oil chambers are fluidically connected with each other through an oil passage;
- an oil return tube that is arranged in the vertical direction through the core portion to discharge oil introduced from one side of the core portion toward the other side of the core portion through the oil chambers and the oil passages; and
- a heat-transfer suppressing means that is arranged between the oil chambers and the oil return tube to suppress heat transfer between the oil flowing in the oil chambers and the oil flowing in the oil return tube.
2. The core structure according to claim 1, wherein
- the heat-transfer suppressing means is a heat-transfer suppressing chambers that are arranged between the oil chambers and the oil return tube and are fluidically connected with the cooling water chambers.
3. The core structure according to claim 1, wherein
- the heat-transfer suppressing means is a heat-transfer suppressing chambers that are arranged between the oil chambers and the oil return tube and are filled with air.
Type: Application
Filed: Nov 28, 2006
Publication Date: Jun 7, 2007
Applicant:
Inventor: Norimitsu Matsudaira (Tokyo)
Application Number: 11/604,876
International Classification: F28F 3/08 (20060101);