Patent Application
20090095761
The present invention relates to a pressure type reserve tank, and in particular relates to a structure thereof with improved pressure resistance.
Conventionally, in order to properly adjust the amount of coolant and internal pressure in a radiator used for a motor vehicle or the like, technology is known, in which a pressure type reserve tank is provided in a coolant circuit connecting between an engine and the radiator. Such technology is disclosed in Japanese utility model application laying-open No. (Jikkaisho) 61-94232 and Japanese patent application laying-open No. (Tokkaihei) 6-146883.
The pressure type reserve tank of this kind is provided with a pressure cap for blocking out an inner space thereof from open air so as to apply pressure to an interior of the reserve tank, thereby obtaining a sealing structure that can perfectly seal up coolant contained therein.
Therefore, the pressure type reserve tank is different from an open type one, in that the coolant is circulated in the coolant circuit, having the pressure type reserve tank as a part thereof, in a state that the coolant is free from contact with the open air so that the coolant can be prevented from reduction of its quantity due to its vaporization and also prevented from its degradation due to contact and reaction with the open air.
On the other hand, as shown the conventional reserve tank disclosed in the latter related art, the reserve tank is normally constructed so that an interior space of the reserve tank is defined into a plurality of chambers in a lattice arrangement by using a plurality of partition wall portions. The partition wall portions defining each chamber are formed with a slit through which the gas-liquid mixed coolant can freely flow between the adjacent chambers, so that the gas and the liquid can be separated from each other when the gas-liquid mixed coolant flows through the slit. As described above, the pressure type tank can separate the gas contained in the coolant circuit into the gas and the liquid, thereby providing effects of improving gas-liquid separation performance and others relative to those obtained by using the open type one.
The conventional pressure type reserve tank, however, encounters a problem in that stress concentration could occur in a specific portion of the partition wall portions due to application of the internal pressure, because the interior space is divided into chambers arranged in the lattice arrangement by using the plurality of partition wall portions formed with the slits. This stress concentration could cause a crack and/or destruction of the partition walls.
In order to remove such damages, measures conceivable to improve rigidness of the partition wall portions would be obtainable by using a partition wall formed to be larger in thickness and/or by reducing the length of the slits thereof. However, the former measures causes its material cost and weight to be increased, and the latter measures causes the gas-liquid separation performance to be deteriorated, due to lower amount of the coolant that comes and goes between the adjacent chambers.
The present invention is made to remove the above-described problems, and its object is to provide a pressure type reserve tank which can decrease stress concentration due to internal pressure in the pressure type reserve tank and improve a gas-liquid separation performance thereof.
According to an aspect of the present invention there is provided a pressure type reserve tank, which includes a liquid-tight outer circumferential wall portion which contains liquid in a sealed state, a central wall portion which is shaped in a substantially circular cylinder to form a central chamber therein and is arranged in the center of an inner space of the outer circumferential wall portion, and a plurality of partition wall portions which radially extend from the central wall portion to the outer circumferential wall portion to define a plurality of outer circumferential chambers formed between the central wall portion and the outer circumferential wall portion and around the central chamber. A plurality of slits is provided on the central wall portion to fluidically communicate the central chamber and the outer circumferential chambers with each other.
In the pressure type reserve tank of the present invention, there are provided the central wall portion, arranged in the center of the reserve tank, and the partition wall portions, radially extending from the central wall portion to the outer circumferential wall portion to define the plurality of outer circumferential chambers, where the slits are formed on the central wall portion to fluidically communicate the central chamber and the outer circumferential chambers. Therefore, the internal pressure to be applied can be uniformly dispersed from the central wall portion to the outer circumferential wall portions, so that the stress concentration due to the internal pressure can be avoided. In addition, the slit can be set to have a most appropriate length thereof, thereby increasing the gas-liquid separation performance in the pressure type reserve tank of the present invention.
Hereinafter, a pressure type reserve tank of an embodiment according to the present invention will be described with reference to the accompanying drawings.
First, an entire construction of the pressure type reserve tank of the embodiment will be described.
As shown in
As shown in
First to fourth slits 6a to 6d are formed, to be vertically long, on a lower portion of the upper circular-cylinder portion 3 at their positions which are away from portions connecting the upper circular-cylinder portion 3 and the upper partition wall portions 4a to 4d with each other, having a predetermined depth (a slit length) of the slits 6a to 6d. These first to fourth slits 6a to 6d fluidically communicate the first upper tank chamber 5a with the second to fifth upper tank chambers 5b to 5e, respectively.
An inlet port P1 is formed in shape of a cylinder, laterally projecting from the outer circumferential wall portion 1a, so as to fluidically communicate with an interior of the second upper tank chamber 5b, and a pressure-cap attachment port C1 is formed in a shape of a cylinder, projecting upward from the outer circumferential wall portion 1a, so as to fluidically communicate with the fourth upper tank chamber 5d.
As shown n
First to fourth slits 10a to 10d are formed, to be vertically long, on an upper portion of the lower circular-cylinder portion 7 at their positions which are away from portions connecting the lower circular-cylinder portion 7 and the lower partition wall portions 8a to 8d with each other, having a predetermined depth (a slit length) of the slits 10a to 10d. These first to fourth slits 10a to 10d fluidically communicate the first lower tank chamber 9a with the second to fifth lower tank chambers 9b to 9e, respectively.
The first to fourth slits 6a to 6d of the upper vessel 1 and the first to fourth slits 10a to 10d are formed at the positions where they are free from an overlapped relationship therewith when the upper vessel 1 and the lower vessel 2 are coupled with each other.
An outlet port P2 is formed in a shape of a cylinder, laterally projecting from the lower outer circumferential wall portion 2a to fluidically communicate with the fourth lower tank chamber 9d.
Incidentally, the upper circular-cylinder wall portion 3 and the lower circular-cylinder wall portion 7 correspond to a central wall portion of the present invention.
The upper vessel 1 and the lower vessel 2 are made of plastic material, and they are formed by using upper and lower dies so that the tank main body TA is integrally formed by the following manufacturing processes. The flange portion F1 of the upper vessel 1 and the flange portion F2 of the lower vessel 2 are faced with each other, and then the both flange portions F1 and F2, the upper and lower circular-cylinder wall portions 3 and 7, and the upper partition wall portions 4a-4d and 8a-8d are heated to be melted to be joined with one another at an adhesion portion PK as shown in
Therefore, as schematically shown in
Incidentally, the chamber 13a corresponds to a central chamber of the present invention, and the chambers 13b to 13e correspond to outer circumferential chambers of the present invention.
As shown in
Therefore, the inner space of the tank main body TA of the embodiment is divided into the plurality of chambers 13a to 13e by the upper and lower outer circumferential wall portions 1a and 2a, the circular-cylinder wall portion 11 arranged in the center of the internal space, and the partition wall portions 12 radially extending from the circular-cylinder wall portion 11 to the outer circumferential wall portions 1a and 1b. The slits 6a to 6d and the slits 10a to 10d are provided so that the chamber 13a formed in the circular-cylinder wall portion 11 can fluidically communicate with the chambers 13b to 13e adjacent to the chamber 13a through the slits 6a to 6d and the slits 10a to 10d.
The thus-constructed pressure type reserve tank is installed, in parallel with the radiator 21, in a coolant circuit CC which fluidically connects an engine 20 and a radiator 21 with each other so as to flow coolant CL therebetween.
Specifically, the inlet port P1 of the pressure type reserve tank is fluidically connected with a coolant-discharge-side part, where the coolant CL is discharged from the engine 20, of the coolant circuit CC, while the outlet port P2 is fluidically connected with an intermediate portion, which is located between a thermostat 22 and a water pump 23, of a coolant-flow-in-side part, where the coolant CL flows in the engine, in the coolant circuit CC.
Next, the operation of the pressure type reserve tank of the embodiment will be described.
A pressure cap C attached to the pressure-cap attachment port C1 keeps the internal pressure in the inner space of the tank main body TA at approximately 1 Kg/cm2 for example. The gas-liquid mixed coolant CL entering the chamber 13b from the inlet port P1 flows into the chamber 13a through the slits 6a and 10a, and then the coolant CL in the chamber 13a is separated and flows into the chambers 13c to 13e at the same time through the slits 6b to 6d and 10b to 10d, respectively. The gas and the liquid are substantially separated from each other while the coolant CL passes through the chambers 13a to 13e, and then the coolant CL is discharged from the outlet port P2.
In this process, the internal pressure is can be uniformly dispersed at the central wall portion 11 and the outer circumferential wall portions 1a and 1b, so that the stress concentration due to the internal pressure can be avoided because the inner space of the tan main body TA is divided into the plurality of chambers 13a to 13e by the circular-cylinder wall portion 11 and the partition wall portions 12 which extend from the circular-cylinder wall portion 11 to the outer circumferential wall portions 1a and 2a.
The pressure type tank body of the embodiment has the following effects.
In the pressure type reserve tank of the embodiment, the inner space of the tank main body TA is divided into the plurality of chambers 13a to 13e by the circular-cylinder wall portion 11, which is formed in a substantially circular cylinder and arranged in the center of the inner space, and the partition wall portions 12 which extend from the circular-cylinder wall portion 11 to the outer circumferential wall portions 1a and 2a. This can remove the stress concentration due to the internal pressure, improving the gas-liquid separation performance of the reserve tank.
In this case, although the circular-cylinder wall portion 11 tends to decrease its rigidness due to the existence of the slits 6a to 6d and 10a to 10d, its rigidness can be sufficiently improved by using the partition wall portions 12 for supporting the circular-cylinder wall portion 11. This enables the circular-cylinder wall portion 11 to be free from a crack and/or destruction therein even when the circular-cylinder wall portion 11 and the partition wall portions 12 have the same thicknesses as those of the conventional ones or when they have thicknesses smaller than those of the conventional ones.
In addition, the coolant CL in the chamber 13a flows into the chambers 13c to 13e through the slits 6b to 6d and 10b to 10d at the same time, where the gas-liquid mixed coolant CL can be gas-liquid separated efficiently because of the simultaneous communications of the coolant CL in a gas-liquid state, not sequential communication thereof, thereby further improving the gas-liquid separation performance.
Although the embodiment has been explained as described above, the present invention is not limited to the above-described embodiment and it includes its design change or modification.
For example, the number of the divided chambers formed in the tank main body TA can be set appropriately, and the configuration, the number and positions of the slits can also be set appropriately.
In addition, although the circular-cylinder wall portion 11 might be changed into, for example, a hexagonal-cylinder wall portion or an octagonal-cylinder wall portion, it is not desirable to form angled corners because of stress concentration on the corners. In such the cases, their corners are preferably formed to be rounded so as to avoid the stress concentration in the corners.
The entire contents of Japanese Patent Application No. 2005-318623 filed on Nov. 1, 2005 are incorporated herein by reference.
The pressure type reserve tank of the present invention is adaptable to a tank, inner space of which is sealed and pressurized, for separating gas, such as air, from liquid medium such as coolant, where the tank is used for a radiator of a motor vehicle or the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-318623 | Nov 2005 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2006/320527 | 10/16/2006 | WO | 00 | 5/12/2008 |
