JPH0721394B2 - Automotive heat exchanger - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat exchanger for automobiles, and is particularly effective when used as an oil cooler for cooling engine oil for automobiles.

[Prior art and its problems]

It has been conventionally known that an oil cooler for cooling engine oil for automobiles is arranged in a lower tank of a radiator for automobiles, and the engine oil is cooled by engine cooling water. For example, Japanese Utility Model Laid-Open No. 55-3140 discloses that an oil cooler is fixed to a resin wall of a lower tank of a radiator.

In this conventional type heat exchanger, as shown in FIG. 2, the oil cooler 5 was brazed to the nipple 7, and the nipple 7 was held by the lower tank 4 via the O-ring 11. The nipple 7 is fixed to the wall surface of the resin tank 4 by the first nut 6. A pipe 9 for inflowing (outleting) engine oil is arranged at the tip of the nipple 7, and the pipe 9 is crimped to the nipple 7 by a fixing nut 8.

However, according to the study by the present inventors, it was confirmed that the flow of oil flowing into the oil cooler or the flow of oil discharged from the oil cooler may be obstructed by the pipe portion.

As a result of examination by the present inventors regarding the reason for inhibition, the following reason was recognized. The nipple 7 and the pipe 9 are formed of a soft metal material with respect to the nut 8 in order to enhance the metal contact property. For example,
The nipple 7 and the pipe 9 are made of brass, and the nut 8 is made of a steel material. Further, in a heat exchanger for a vehicle, the nut is required to have a sufficient tightening force in order to keep a good watertightness for a long period of time because it is subjected to vibrations of the vehicle. Therefore, the nut 8 may be tightened on the nipple 7 with an excessive load. In such a case, since the nipple 7 is softer than the nut 8, there is a possibility that the nipple 7 may be crushed inward as shown by A portion in FIG.

That is, the tip of the nipple has an inclined surface 71, and the tip of the pipe 9 has a tapered shoulder portion 91 corresponding to the inclined surface 71. Further, the nut 8 is also formed with a tapered pressing portion 81 so that the tapered shoulder portion 91 can be pressed by surface contact. in this way,
Since each of the nut 8, the pipe 9, and the nipple 7 has an inclined portion, the inclined surface 81 of the nut 8 may cause the tip portion A of the nipple 7 to bend inward.

In this way, the inward bending of the tip of the nipple reduces the inner diameter of the nipple passage 72. Therefore, the tip portion A gives flow resistance to the fluid flowing through the nipple 7.

[Problems to be Solved by the Invention]

The present invention has been devised in view of the above points, and a pipe,
It is an object of the present invention to prevent a large flow resistance from being given to the fluid flowing inside the fluid passage portion of the nipple.

[Configuration and operation]

In order to achieve the above object, in the present invention, a shoulder portion that contacts the nipple is formed at the end of the pipe, and a cylindrical portion is formed in the vicinity of this shoulder portion. Then, the diameter of the cylindrical portion is set to be a predetermined amount larger than the diameter of other portions of the pipe. Therefore, according to the present invention, the inner diameter of the portion of the nipple and the pipe that comes into contact with the nipple is larger than the inner diameter of the other portion of the pipe.

As a result, even if the tip portion of the nipple bends inward, the inner diameter of the nipple portion does not become smaller than the inner diameter of other portions of the pipe.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. Third
The figure shows an automotive radiator in which the heat exchanger of the invention is used. In the figure, 100 is an upper tank and 104 is a lower tank, both of which are made of glass fiber reinforced nylon resin. A tube 103 is arranged between the upper tank 100 and the lower tank 104, and a radiating fin 105 is arranged between the tubes 103. In addition, an inlet pipe 101 is formed in the upper tank 100, and engine cooling water of a vehicle running engine (not shown) flows into the upper tank 100 through the inlet pipe 101. On the other hand, an outlet pipe 106 is formed in the lower tank 104, and the engine cooling water flows out from the outlet pipe 106 to the vehicle running engine side.

An injection hole 108 is further formed in the upper tank 100, and the engine cooling water is injected through the injection hole 108.

This radiator for an automobile distributes engine cooling water introduced from an inlet pipe 101 to each tube 103 in an upper tank 100. When flowing through each tube 103, the engine cooling water exchanges heat with the cooling air sent from a cooling fan (not shown), and the temperature of the engine cooling water is lowered. In this heat exchange, the heat exchange efficiency is increased by the radiation fins. The engine cooling water cooled when passing through the tube 103 flows into the lower tank 104, and then flows out from the outflow pipe 106 to the engine side. Therefore, the relatively low-temperature engine cooling water after cooling flows into the lower tank 104.

In this lower tank 104, as shown in FIG. 1, a double pipe type oil cooler 5 is arranged. Oil cooler 5
Is made of a metal having good heat conductivity, such as brass, and engine oil flows between the inner pipe 51 and the outer pipe 52. A brass nipple 7 is brazed to the outer tube 52. The nipple 7 is
It is composed of a brim portion 73 and a cylindrical portion 74, and the cylindrical portion projects outward from a communication hole 109 formed in the lower tank 104. In addition, the collar 73 of the nipple 7 and the lower tank 104
The space between and is kept watertight by the O-ring 11.

A screw is provided on the outer surface of the cylindrical portion 74 of the nipple 7, and the first nut 6 is screwed into this screw portion, and the lower tank 104 is secured by the first nut and the collar portion 73 of the nipple 7. It has a structure of sandwiching.

The tip of the cylindrical portion 74 of the nipple 7 is formed with an inclined surface 71 that is inclined outward. The tapered shoulder 91 formed at the end of the pipe 9 comes into surface contact with this inclined surface. And
In this state, the pipe 9 is pressed against and held by the nipple 7 by the nut 8. That is, the nut 8 is screwed with the threaded portion formed on the outer surface of the cylindrical portion 74 of the nipple 7, and the tapered surface 81 formed on the nut 8 causes the pipe 9 to move.
The tapered shoulder portion 91 of the nipple 7 can be pressed against the inclined surface 71 side of the nipple 7.

A portion of the pipe 9 adjacent to the tapered shoulder portion 91 is a cylindrical portion 20. The outer shape of the cylindrical portion is larger than the outer shapes of the other parts of the pipe 9 by a predetermined amount. For example, in this example, the outer diameter of the cylindrical portion is 12 mm, and the outer diameter of the other pipe portions is 10 mm.

A portion of the nut 8 facing the cylindrical portion 20 serves as a cylindrical holding portion 83. This cylindrical holder
83 and the cylindrical portion of the pipe 9 face each other with a very small clearance.

The pipe 9 is bent at a portion adjacent to the cylindrical portion. That is, the pipe 9 is formed with an arcuate portion 95. Further, an end portion of the pipe 9 opposite to the tapered shoulder portion 91 is led out by a predetermined amount to form a retaining portion 96. A rubber material hose (not shown) is connected to the retaining portion. Then, engine oil for an automobile engine is introduced into the pipe 9 through the rubber material hose.

Next, the assembly process of the heat exchanger will be described.

In the heat exchanger of this example, first, the nipple is brazed to the oil cooler 5, and in that state, the oil cooler and the nipple 7 are carried into the lower tank 104, and the tubular portion 7 of the nipple 7
4 is projected outward from the communication hole 109 of the lower tank 104.
In that state, the first nut is tightened to fix the nipple 7 and the oil cooler 5. In that state, pipe 9
The tapered shoulder portion of is contacted with the tip inclined surface 71 of the nipple 7. After that, the nut 8 is inserted from the other end side bulging portion 96 side of the pipe onto the pipe 9 (state shown in FIG. 4).

Here, in the heat exchanger of this example, since the nut 8 and the cylindrical holding surface 83 have almost the same diameter as the outer diameter of the cylindrical portion 20 of the pipe 9, the diameters of other parts of the pipe 9 are different. Rather, the inner diameter of the cylindrical holding portion of the nut 8 is larger. Therefore, in the heat exchanger of this example, it is possible to assemble the nut 8 on the pipe 9 after that even when the pipe 9 is held at the predetermined position. Further, in the heat exchanger of this example, a predetermined sufficient gap is formed between the inner diameter of the nut 8 and the outer diameter of the pipe 9 at a portion other than the cylindrical portion 20. Therefore, as shown in FIG.
Even if the circular hole portion 95 is bent in a small upright position, the nut 8 can be properly assembled. In other words,
Even when the assembly width L in FIG. 4 is small, the nut 8 can be assembled in the heat exchanger of this example.

Next, at the time of this assembling, the effect of this example will be described in comparison with the assembling of the conventional pipe 9 having no cylindrical portion. FIG. 5 shows a conventional pipe shape without the cylindrical portion 20. That is, in the conventional pipe 9,
Since it does not have a large-diameter cylindrical portion, the inner diameter of the cylindrical holding portion 83 of the nut 8 must match the outer diameter of the pipe 9 in the entire length of the pipe 9. Therefore, it is impossible to assemble the nut 8 to the pipe 9 after molding the pipe 9.

Therefore, in the conventional case, the tapered shoulder portion 91 is formed by expanding the end portion of the pipe 9 with the nut 8 inserted in the pipe 9 in advance. Therefore, the conventional pipe 9
Then, in order to expand the pipe with the nut 8 assembled,
The predetermined holding part M was required. Therefore, the assembly length L becomes very large as shown in FIG. Further, in the conventional pipe 9, since there is almost no difference between the pipe outer diameter and the nut inner diameter, it is not possible to form the small upright circular hole-shaped portion 95 in the pipe 9.

As described above, in the heat exchanger of this example, the nut 8 can be assembled to the pipe 9 after the pipe 9 is molded, so that the assembly length L of the pipe 9 is greatly reduced. .

The heat exchanger assembled as described above is then
A rubber material hose is connected to the end of the pipe 9.

Then, it flows into the oil cooler 5 from the engine oil introduced from the rubber material hose and the pipe 9 through the passage portion 72 of the nipple 7. While the engine oil flowing into the oil cooler passes through the oil cooler 5,
The engine cooling water in the lower tank 104 is heat-exchanged to cool the oil cooler. The oil cooler that has finished cooling flows out to the pipe 9 side from the nipple 7 formed on the other end side of the oil cooler.

Although only one nipple and the pipe 9 are shown in FIG. 1, a nipple and a pipe having the same shape are formed on the other end side of the oil cooler 5.

Here, the heat exchanger of this example is arranged in the engine room of the automobile together with the radiator for the automobile. Therefore,
You will be strongly affected by the vibration of the car.

Oil cooler 5, nipple 7, nut 8 and pipe 9
Are fixed to the lower tank 104 of the radiator, so that they are placed on the same vibrometer as the radiator. On the other hand, the hose connected to the pipe 9
Further, a metal pipe (not shown) will be connected and placed on another vibrometer. Therefore, a large bending stress is generated in the pipe 9 due to the vibration of the automobile.

However, in the heat exchanger of this example, even if such a large bending moment is generated, the seal between the pipe 9 and the nipple 7 can be well achieved over a long period of time.

That is, in the heat exchanger of this example, the end portion of the pipe is a cylindrical portion with a large diameter, and further, a tapered locking shoulder portion is formed outside the cylindrical portion. . Therefore, in this example, the pressure receiving area of the locking shoulder portion is large. In this way, since the nut 8 is crimped to the locking shoulder portion having a large pressure receiving area, the holding force of the pipe 9 becomes sufficient. Moreover, the pipe 9 of this example has a cylindrical portion having a larger diameter than the other parts of the pipe 9, and since the cylindrical portion 20 is held by the nut 8, the holding in the cylindrical portion is performed. The power is also sufficient.

This is particularly effective when the diameter of the pipe 9 other than the cylindrical portion 20 is reduced. That is, if the pipe 9 has a small diameter, the holding force is small no matter how much the nut 9 holds. However, as in this example, if the pipe 9 has a large diameter cylindrical portion, the holding force of the cylindrical portion 20 and the nut 8 is sufficiently large even if the diameter of the pipe 9 itself is small. Maintained at.

Further, in the heat exchanger of this example, since the pipe has the large-diameter cylindrical portion, the stepped portion 97 is formed between the cylindrical portion and the other portion of the pipe. Due to the presence of the stepped portion 97, the strength of the entire pipe can be improved. Thus, improving the strength of the pipe 9 is
Can be made thinner, which in turn leads to a reduction in overall weight.

Moreover, in the heat exchanger of this example, the inner diameters of the cylindrical portion 20 and the passage portion 72 of the nipple 7 are larger than the inner diameters of the other portions of the pipe 9 by a predetermined amount. Even if the tip of is bent inward,
It does not give flow resistance to the oil flowing through the pipes and nipples. That is, even if the tip portion of the nipple 7 is bent inward and the opening area at that portion is reduced, it is still larger than the sectional view of the other portion of the pipe 9, and as a result, the tip portion of the nipple 7 is reduced. Distribution resistance in the department is no longer an issue.

In the example described above, the arc-shaped portion 95 of the pipe 9 has a temperature of about 90 ° C.
Although it is assumed to be bent, it goes without saying that it may be bent at 90 ° C or higher. In the above example, the nipple 7 and the pipe 9 are made of brass, but other materials,
For example, it may be made of aluminum alloy or the like.

〔The invention's effect〕

As explained above, in the heat exchanger of the present invention, 1. The influence of the flow resistance due to the bending of the tip of the nipple can be eliminated.

2. The mounting length L of the pipe 9 can be reduced.

3. The pressure receiving area of the tapered shoulder at the end of the pipe can be increased to increase the mounting force of the pipe.

4. Since a large-diameter cylindrical portion is formed at the end of the pipe, the area of contact between the pipe and the nut increases, and the pipe is firmly held.

5. Since the cylindrical portion is formed on the pipe, a step is formed at the end of the cylindrical portion, and as a result, the strength of the pipe is improved.

And so on.

[Brief description of drawings]

1 is a sectional view showing an embodiment of the heat exchanger of the present invention, FIG. 2 is a sectional view showing a conventional heat exchanger, and FIG. 3 is a radiator to which the heat exchanger shown in FIG. 1 is attached. FIG. 4 is a front view, FIG. 4 is an explanatory view showing an assembled state of the heat exchanger shown in FIG. 1, and FIG. 5 is an explanatory view showing an assembled state of the conventional heat exchanger shown in FIG. 5 ... Heat exchanger body, 7 ... Nipple, 8 ... Nut, 9 ... Pipe, 2
0 ... Cylindrical part, 71 ... Inclined surface, 91 ... Tapered shoulder part, 95 ... Bent part, 104 ... Lower tank.

Claims (4)

[Claims] 1. A heat exchanger main body disposed in a tank of an automobile radiator, a nipple connected to the heat exchanger main body and protruding outward from a wall surface of the radiator tank, and a tip of the nipple. A pipe for coming in and out of the heat exchange body through the nipple, and a fixing nut for fixing the pipe to the nipple,
A surface of the nipple that contacts the pipe is an inclined surface, and an end surface of the pipe that contacts the nipple is a tapered shoulder that corresponds to the inclined surface, and the end of the pipe is the same. A cylindrical portion having a predetermined diameter larger than the outer shape of the other portion of the pipe is formed near the tapered shoulder portion, and the inner surface of the nut is formed so as to contact the large diameter portion of the pipe. A heat exchanger for automobiles, which has been characterized. 2. The heat exchanger for an automobile according to claim 1, wherein the pipe is bent and formed at a portion other than the cylindrical portion. 3. The heat exchanger for an automobile according to claim 1, wherein the cylindrical portion of the pipe has a large diameter of about 2 mm larger than the outer shape of the other portion of the pipe. A heat exchanger for automobiles, which is characterized in that 4. The heat exchanger for an automobile according to claim 1, wherein the nipple and the pipe are made of a metal material softer than the nut. .