JPH11159974A - Oil cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil cooler suitable for reduction in size. SOLUTION: A water side inner fin 102d and an oil side inner fin 102c are rectangular waveform, the fins 102c and 102d are brazed to a tube 103d, with the water-side inner fin 102d thicker than the oil-side inner fin 102c. So, with no degradation in pressure-resistance of an oil cooler, the oil-side inner fin 102c can be thinner for reduced pressure drop in the tube 103d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil cooler for cooling engine oil by performing heat exchange between cooling water of a water-cooled engine and engine oil circulating in the water-cooled engine. It is valid.

[0002]

2. Description of the Related Art The structure of an oil cooler is, for example,
As described in Japanese Patent Application Laid-Open No. 10-357, a cooling water passage and an oil passage are partitioned by a core plate to form an oil passage (tube) in the cooling water passage, and cooling water and an engine are provided on both surfaces (both passages) of the core plate. This is a brazed offset fin that promotes heat exchange with oil.

[0003]

By the way, in recent years, the number of devices arranged in an engine room has been increasing, and in addition, the cabin has been expanded without increasing the size of the vehicle. In order to achieve this, the clearance (clearance) between the devices provided in the engine room is reduced.

[0004] However, when the gap between the devices becomes small,
Since the assemblability (mountability) of each device is degraded and the production cost of the vehicle may increase, the demand for miniaturization of each device is increasing. Therefore, the inventors have tried to reduce the size of the oil cooler by reducing the fin pitch and fin height of the offset fins and increasing the density of the fins. It was found that the fins were not suitable for increasing the density of the fins in terms of processing speed and life of the press die.

[0005] As is well known, engine oil is
It circulates through the engine and lubricates and cools the moving parts such as pistons and camshafts.If the density of the fins is increased unnecessarily, the pressure loss in the oil cooler increases, and the engine oil Cannot be supplied to every corner of the vehicle, which may cause a problem of burning of the engine.

In order to solve this problem, it is conceivable to reduce the pressure loss in the oil passage by reducing the thickness of the fin on the oil passage side. However, if the thickness of the fin on the oil passage side is simply reduced, A new problem occurs in that the pressure resistance (mechanical strength) is reduced. Further, since the oil passage is formed in the cooling water passage, for example, when the thickness of the fins on both passages is made equal as described in the above publication, when the fins are heated during brazing, The temperature rise characteristics differ between the two fins. For this reason, the fin on the side of the cooling water passage where the degree of temperature rise becomes large melts (erosion occurs).
Therefore, a brazing defect occurs.

The present invention has been made in view of the above circumstances, and has as its object to provide an oil cooler suitable for downsizing.

[0008]

The present invention employs the following technical means to achieve the above object. Claim 1
In the inventions described in Nos. 1 to 6, the water-side fin (102d) and the oil-side fin (102c) are corrugated (corrugated), and these fins (102d, 102c)
Is brazed to the tube (103d), and the thickness (tw) of the water-side fin (102d) is adjusted to the oil-side fin (1).
02c) is characterized in that it is larger than the thickness (to).

First, since the fins (102c, 102d) are corrugated (corrugated), the fins (102c, 102d) are formed by a roller forming method similarly to the corrugated fins used in heat exchangers such as radiators and condensers. 102
d) can be molded. For this reason, a fin having a smaller fin pitch can be formed as compared with an offset type fin formed by press forming, so that the pressure resistance (mechanical strength) of the tube (103d) can be reduced like a multi-hole tube of a capacitor. The fins can be improved, and the density of the fins can be further increased.

Therefore, the thickness (to) of the oil-side fin (102c) can be reduced in order to reduce the pressure loss in the tube (103d) without impairing the pressure resistance of the tube (103d). Second, the thickness (tw) of the water-side fin (102d) is set to the oil-side fin (1d).
02c), the temperature increase of the water-side fin (102d) can be prevented from increasing more than the temperature increase of the oil-side fin (102c) during brazing. The erosion of 102d) can be prevented, and poor brazing of both fins (102c, 102d) can be prevented.

As described above, according to the present invention, it is possible to reduce the size of the oil cooler without impairing the quality of the oil cooler such as brazing properties and pressure resistance. By the way, since the water-side fin (102d) is always in contact with the cooling water, the water-side fin (102d) is more easily corroded than the oil-side fin (102c). For this reason, for example, when both fins (102d, 102c) have the same thickness,
Naturally, the corrosion of the water-side fin (102d) proceeds faster than that of the oil-side fin (102c). Therefore, the life of the oil cooler is determined by the life of the water-side fin (102d) which is easily corroded.

On the other hand, according to the present invention, the thickness (tw) of the water-side fin (102d) is smaller than that of the oil-side fin (1d).
Since the life of the water-side fin (102d), which is easily corroded, can be extended since the thickness (to) is larger than the thickness (to) of the oil cooler 02c), the life of the oil cooler can be extended. The thickness (tw) of the water-side fin (102d) is desirably 1.05 times or more the thickness (to) of the oil-side fin (102c).

The thickness (t) of the water-side fin (102d)
w) is an oil-side fin (1).
It is preferable that the thickness (to) is not less than 1.10. The dimensions of each part of the oil-side fin (102c) are defined by the fin height (ho).
Is 1 to 3 mm, and the thickness (to) of the fin is 0.05 to
0.3 mm, the fin pitch (fpo) is 4 mm or less, and the thickness (tp) of the tube (103d) is 0.2 m.
m or more.

The dimensions of each part of the water-side fin (102d) are, as described in claim 5, a fin height (hw) of 1 to 3 mm and a fin thickness (tw) of 0.05 to 0.05.
0.3 mm, fin pitch (fpw) 2-4 mm
It is desirable that In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means of embodiment mentioned later.

[0015]

(First Embodiment) FIG. 1 is a sectional view of an oil cooler 100 according to the present embodiment, and the oil cooler 100 is fixed to a wall surface of a water-cooled engine body (hereinafter abbreviated as engine). Is what is done.

Reference numeral 101 denotes a cylindrical filter element (hereinafter, abbreviated as a filter) for filtering foreign matter in engine oil (hereinafter, abbreviated as an oil) circulating in the engine, and 102 denotes an engine cooling water (hereinafter, abbreviated as a filter). An oil cooler core (hereinafter abbreviated as a core) that performs heat exchange between the oil and the cooling water. This core part 102
Is a core plate 102 press-formed into a predetermined shape.
A core unit (core unit) formed by brazing an oil-side inner fin 102c in the form of a rectangular wave (rectangular corrugate) between the core plates 102a, 102b.
02b in the thickness direction and brazed (see FIG. 2).

That is, the two core plates 102a, 102
b, an oil passage (tube) through which the oil flows and a cooling water passage 103c through which the cooling water flows through the core portion 102
103d and an oil passage (tube) 103d in the cooling water passage 103c. And between each core unit, a cooling wave side inner fin 102d of a rectangular wave shape (rectangular corrugated shape) is brazed to each core plate 102a, 102b, and the thickness tw of the water side inner fin 102d is set to the oil side inner fin. The thickness is larger than the thickness to of the fin 102c.

Further, both inner fins 102c, 102
As shown in FIG. 3, a well-known louver 103e, which makes cooling water and oil meander on both the front and back surfaces of the inner fins 102c and 102d, as shown in FIG.
c and 102d are integrally cut and raised. By the way,
At the time of brazing the core part 102 and the filter bracket 105, as shown in FIG. 1, the engine mounting surface 104a of the bracket part 104 is on the lower side, and the core plates 102a, 102b, and both inner surfaces of which are covered with brazing material on both front and back surfaces. The brazing is performed in a state where the fins 102c and 102d and the partition member 103 are stacked in this order. As a result, gravity acts on the core portion 102, so that the core portion 102
Can be reliably brazed.

Reference numeral 103 denotes a space in which the core unit 102 is provided (hereinafter, this space is referred to as a core space) 103.
a partition member made of metal (aluminum in the present embodiment) that partitions the space 103a and the space 103b in which the filter 101 is provided (hereinafter, this space is referred to as a filter casing portion) 103b. The member is integrally brazed to a metal (aluminum in this embodiment) bracket member 104 for fixing the member to the engine. Hereinafter, the integrally brazed partition member 1 will be described.
03 and the bracket member 104 are collectively referred to as a filter bracket 105.

The core space 103a is
2 as well as a part of a passage 102c of the cooling water flowing through the core 102. For this reason, the core part 102 is connected to the filter bracket 105 (partition member 10).
3 and the inner wall of the bracket member 104). Reference numeral 102e denotes an inflow opening through which the cooling water flows, and 102f denotes an outflow opening through which the cooling water having undergone heat exchange in the core portion 102 flows out.
A connection pipe 102g for connecting an external pipe (not shown) is brazed to 102f.

Reference numeral 106 denotes a rubber check valve for preventing oil flowing into the filter casing 103b through the core 102 from flowing back to the core 102, and 107 denotes a filter which is filtered by the filter 101. This is a pipe part for allowing the oil to flow through the center of the core part 102 and return to the engine. A rubber seal member 108 is disposed between the tube 107 and the filter 101 to seal the gap between the two.

Reference numeral 109 denotes a disc spring-shaped elastic member for pressing the filter 101 toward the partition member 103;
The elastic member 109 is provided on the filter casing 103b.
Is pressed by a lid 110 that closes the opening. In addition. The lid 110 is screwed to the filter casing 103b (bracket 104), and the gap between the two 110 and 103b is sealed by an O-ring 111. Reference numeral 104b denotes a bolt hole into which a bolt (not shown) for fixing the filter bracket 105 (bracket portion 104) to the engine is inserted.
104b is a two-sided width with which a tool such as a spanner is engaged when turning the lid 110.

Incidentally, the oil cooler 1 according to the present embodiment
When the filter 101 is replaced at 00, the lid 11
Remove the filter 101 and replace it. Next, features of the present embodiment will be described. According to the present embodiment,
First, since the inner fins 102c and 102d have a rectangular wave shape, both the inner fins 102c and 102d can be formed by a roller forming method, similarly to the corrugated fins used in heat exchangers such as radiators and condensers. it can.

For this reason, a fin having a smaller fin pitch can be formed as compared with an offset type fin formed by press forming. Therefore, like a multi-hole tube of a condenser, the pressure resistance strength of the tube (oil passage) 103d is reduced. Mechanical strength) and the density of the fins can be further increased. Therefore, the thickness to of the oil-side inner fins 102c can be reduced in order to reduce the pressure loss in the tube 103d without impairing the pressure resistance of the tube 103d.

Second, the thickness tw of the water-side inner fin 102d is set to the thickness to of the oil-side inner fin 102c.
Since the temperature of the water-side inner fins 102d is increased during brazing,
Since it is possible to prevent the temperature from increasing more than 2c, it is possible to prevent erosion of the water-side inner fins 102d and to prevent poor brazing.

As described above, according to the present embodiment, the size of the oil cooler 100 can be reduced without deteriorating the quality of the oil cooler 100 such as brazing property and pressure resistance. The thickness tw of the water-side inner fin 102d is equal to the thickness t of the oil-side inner fin 102c.
water inner inner fin 10
Since the life of 2d can be extended, the life of the oil cooler 100 can be extended.

The thickness tw of the water-side inner fin 102d is desirably 1.05 times or more the thickness to of the oil-side inner fin 102c. And more desirably, the thickness tw of the water side inner fin 102d
Is 1. The thickness to of the oil-side inner fin 102c is 1.
10 times or more. The oil side inner fins 10
The dimensions of each part of 2c are such that the fin height ho is 1 to 3 mm, the fin thickness to is 0.05 to 0.3 mm, the fin pitch fpo is 4 mm or less, and the tube 103d
The thickness tp of the (core plates 102a, 102b) is set to 0.
Desirably, it is 2 mm or more (see FIGS. 4 to 9).

The dimensions of each part of the water side inner fin 102d are such that the fin height hw is 1 to 3 mm, the fin thickness tw is 0.05 to 0.3 mm, and the fin pitch f is
It is desirable that pw be 4 mm or less (see FIGS. 4 to 9). FIG. 4 shows the fin thicknesses to and tw of 0.1 m.
m and the thickness tp of the tube 103d is set to 0.6 mm, the louver 103e brazing material flows and the louver 103
This is an examination result in consideration of the fact that e is closed.

Although the cooling water is filled on the core space 103a side and the oil on the filter casing portion 103b side with the partition member 103 interposed therebetween, the partition member 103 and the bracket portion 104 are brazed by brazing. Since they are integrated, as described in, for example, European Patent No. 631804A1 (January 4, 1995),
There is no need to interpose a plurality of O-rings in order to ensure the tightness between 03a and 103b.

Therefore, the number of parts of the oil cooler can be reduced, so that the manufacturing cost of the oil cooler 100 can be reduced, and the number of O-rings, which are consumable parts, can be reduced. Thus, the burden on the vehicle user can be reduced. Also,
Since the number of parts of the oil cooler 100 can be reduced, the size of the oil cooler 100 can be reduced, and the mountability of the oil cooler 100 on a vehicle can be improved.

(Second Embodiment) As shown in FIG. 10, an oil cooler 400 according to this embodiment
A cooling water passage 401 through which cooling water flows is formed by the partition member 103 and the bracket member 104. As a result, the amount of heat exchange between the cooling water and the oil can be increased, so that the oil temperature can be further reduced. As a result, the life of the oil can be extended, so that the life of the oil can be extended.

In the above-described embodiment, the inner fins 102c and 102d have a rectangular wave shape. The present invention is not limited to this, and may have a sine wave shape. Further, in the above-described embodiment, the core unit 102 is a so-called exterior oil cooler in which the core unit 102 is located outside the engine. However, in the present invention, the core unit 102 is provided inside the engine (water jacket (cooling water passage) of the engine). ), Which is a so-called interior type oil cooler.

[Brief description of the drawings]

FIG. 1 is a sectional view of an oil cooler according to a first embodiment.

FIG. 2 is a perspective view of a core part.

FIG. 3 is a sectional view of both inner fins.

FIG. 4 is a graph showing a relationship between an oil (oil) side heat transfer coefficient and a fin height.

FIG. 5 is a graph showing a relationship between a thickness of a core plate (tube) and a stress generated in the core plate.

FIG. 6 is a graph showing the relationship between oil flow resistance and inner fin thickness.

FIG. 7 is a graph showing a relationship between a stress generated in an inner fin and a fin pitch.

FIG. 8 is a graph showing the relationship between the stress generated in the core plate and the thickness of the core plate.

FIG. 9 is a graph showing the relationship between thermal resistance and core plate thickness.

FIG. 10 is a sectional view of an oil cooler according to a second embodiment.

[Explanation of symbols]

102a, 102b: core plate, 102c: oil side inner fin, 102d: water side inner fin, 1
03c: cooling water passage, 103d: tube.

Claims (5)

[Claims] 1. Heat exchange is performed between cooling water of a water-cooled engine and engine oil circulating in the water-cooled engine,
An oil cooler for cooling the engine oil, wherein the casing is provided in a casing (105) constituting a cooling water passage (103c) through which the cooling water flows, and the engine oil is provided in the cooling water passage (103c). A flowing tube (103d); a wavy water-side fin (102d) brazed to the outer wall of the tube (103d);
The corrugated oil-side fins (1) brazed to the inner wall of d)
02c), wherein the thickness (tw) of the water-side fin (102d) is larger than the thickness (to) of the oil-side fin (102c). 2. The thickness (t) of the water-side fin (102d)
w) is the thickness (t) of the oil-side fin (102c).
2. The method according to claim 1, wherein the value is 1.05 times or more of o).
The oil cooler described in. 3. The thickness (t) of the water-side fin (102d)
w) is the thickness (t) of the oil-side fin (102c).
2. The method according to claim 1, wherein the difference is at least 1.10 times of o).
The oil cooler described in. 4. A louver (103e) is formed on the oil-side fin (102c) to meander the engine oil on both front and back sides of the oil-side fin (102c), and the fin height of the oil-side fin (102c) is increased. Sa (ho)
Is 1 to 3 mm, and the thickness (to) of the oil-side fin (102c) is 0.1 mm.
And a fin pitch (fp) of the oil-side fin (102c).
o) It is 4 mm or less, and the thickness (tp) of the tube (103d) is 0.2 mm
The oil cooler according to any one of claims 1 to 3, characterized in that: 5. The fin height (hw) of the water-side fin (102d) is 1 to 3 mm, and the thickness (tw) of the water-side fin (102d) is 0.05.
Fin pitch (fpw) of the water-side fin (102d).
5. The oil cooler according to claim 4, wherein the length is 4 mm or less.