JPH11105864A - Structure of water subtank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve appearance without overflow at joining faces and to prevent occurrence of stress concentration by a method wherein a recessed groove running round along the joining face for absorbing parts melting and flowing on occasion of joining by heat is provided at one of the joining faces of divided parts. SOLUTION: At joining faces of a tank upper part 2 and a tank lower part 3, flanges 2f and 3f respectively projecting outward from the tank are provided, and a recessed groove 5 in a semi-circular section running round along the joining faces is provided at the joining face 3a of the tank lower part 3 on a position coming close to the outside from the center. A notch 6 opened toward the outer circumferential part and running round is provided at the joining face 2a of the tank upper part 2 on a position coming close to the outside from a position corresponding to the recessed groove 5. With the joining faces 2a and 3a pressed together for joining by heating, melted parts flow toward the inside and the outside of the joining faces. However, the outward flow is absorbed by the recessed groove 5 provided at the position coming close to the outside from the center while overflow fills up the notch 6 and is prevented from projecting toward the outside further.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a water sub-tank which is used for a cooling system of an engine, is made of resin, is divided into a plurality of parts, and the joint surfaces of the divided parts are heated and pressed together to be integrated.

[0002]

2. Description of the Related Art Conventionally, it is used for a cooling system of an engine,
As shown in FIG. 5, in a water sub-tank 1 in which a tank upper part 2 having an inlet and a tank lower part 3 are integrally joined by resin molding by dividing into upper and lower parts, upper and lower parts 2 and 3 are joined by joining surfaces 2a and 3a are thermocompression-bonded, and protruding portions 8 and 9 are generated inside and outside the joint surface. The protruding portions 8 and 9 not only have poor appearance, but also cause stress concentration and serve as starting points for cracks. That is, as shown in FIG. 8, the tank 1 is expanded by the internal pressure p acting thereon, so that the outside of the tank becomes a tensile stress, and a stress concentration indicated by a symbol a occurs in the protruding portion 8. Also, if unevenness is also formed on the outer peripheral portion of the protruding portion 8, stress concentration occurs, so it is necessary to delete it. Note that the inner protruding portion 9 is on the compression side, and there is no particular problem.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a water sub-tank structure that does not protrude from the joint surface when heating and joining the divided portions of the tank, improves appearance, and does not cause stress concentration. It is intended to be.

[0004]

According to the present invention, there is provided a water sub-tank structure in which a plurality of divided surfaces are formed, and the joint surfaces of the divided portions are heat-pressed together to form a unit. A concave groove is formed along the joining surface to absorb a portion eluted when the joint is heated.

[0005] The concave groove is provided so as to be shifted outward from the center of the joint surface.

Alternatively, the concave groove is provided near the center of the joint surface.

Providing a concave groove near the center is suitable when the width of the joint surface is small.

[0008] Further, a notch opened in the outer peripheral portion is provided on the other joint surface outside the position facing the concave groove.

[0009] Further, in addition to the above-mentioned concave groove on the outer side, a concave groove is further provided on the inner side.

The cross-sectional shape of the groove is either a semicircle or a triangle.

Therefore, according to the present invention, since the divided portions of the water sub-tank divided into a plurality of parts are integrally joined, when the joint surface is heated and pressed, the melted portion of the joint surface is formed inside and outside. Although flowing in the direction, it is absorbed by the concave groove and the protrusion is suppressed. If the concave groove is provided outward from the center, it can be prevented from protruding to the outside of the tank, and if it is used together with the notch on the opposing joint surface, the protruding part will fit inside the notch and it will look good And concentration of stress can be prevented.

Further, if a concave groove is added inward in addition to the concave groove on the outer side, it is possible to prevent the tank from protruding inward. In addition, a concave groove may be provided in the vicinity of the center for a narrow joint surface where no flange is formed at the joint. If the cross-sectional shape of the concave groove is a semicircular shape or a triangular shape, it is possible to avoid the occurrence of stress concentration due to a void remaining at a corner as in a rectangular groove.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, flanges 2f, 3f projecting outward from the tank are provided at the joint between the tank upper part 2 and the tank lower part 3, respectively. And
The joint surface 3a of the tank lower part 3 is provided with a semicircular concave groove 5 having a semicircular cross-section that goes outward from the center and goes around the joint surface. A notch 6 which is open to the outer peripheral portion is provided near the outer side of the position facing the lower groove 5.

FIG. 2 shows a state after the joining.
The joining surfaces 2a and 3a are heated during joining, and when pressed, the melted portion flows inward and outward of the joining surface, but the outward flow is a concave groove provided outward from the center. Since it is absorbed at 5, the protrusion fills the notch 6 and its outward projection is prevented. Further, in this embodiment, since the concave groove 5 is provided on the outer side, the protrusion 9 to the inside of the tank cannot be completely stopped.
When the internal pressure is applied to the tank 1, it becomes the compression side.
There are no cracks.

In this embodiment, the amount of protrusion of the flanges 2f, 3f is 1 t with respect to the thickness t of the tank.
Approximately 1.5 t, the cross-sectional radius r of the concave groove 5 is 0.25 t
<R <0.5t may be set. And the concave groove 5 is
If the cross section is made into a semicircular or triangular shape, the entire groove is not buried and a gap is not generated at a corner.

The second embodiment shown in FIG. 3 is a case in which the flange of the joining portion of the tank 1 is small, and a concave groove 5A having a triangular cross section is provided near the center of the joining surface 3a of the tank lower portion 3A. Is provided.

Further, in the third embodiment shown in FIG. 4, when there is no flange at the joint, the joining of the tank upper and lower portions 2B, 3B is increased so that the joining area is increased without increasing the tank thickness t. The surfaces 2c and 3c are inclined, and the lower joint surface 3c is provided with a concave groove 5B having a triangular cross section.

The fourth embodiment shown in FIG. 5 is different from the embodiment shown in FIG. 1 in that a concave groove 5C is provided on the inner side in addition to the concave groove 5 on the outer side. As a result, protrusion to the inside of the tank is also prevented.

[0019]

The present invention is constructed as described above, and the portion melted at the time of thermocompression bonding is absorbed by the concave grooves provided on the joint surface of the divided upper and lower portions of the tank, and particularly, the outward portion is applied to the outside of the tank. The protrusion can be prevented, and the work of shaving the protruding portion, which has been conventionally performed, becomes unnecessary. As a result, the appearance can be improved, and the stress concentration does not occur and the strength can be prevented from lowering.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state before joining of an embodiment of a structure of a joining portion of a water sub-tank of the present invention.

FIG. 2 is a cross-sectional view showing a state after the bonding in FIG. 1;

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

FIG. 5 is a sectional view showing a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a conventional water sub tank.

FIG. 7 is a cross-sectional view showing the joint of FIG. 6;

FIG. 8 is a view for explaining stress concentration occurring in the protruding portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Water subtank 2, 2A, 2B ... Tank upper part 3, 3A, 3B ... Tank lower part 2a, 2b, 2c ... Joint surface 3a, 3b, 3c ... Joint surface 5, 5A, 5B, 5C ... concave groove 6 ... notch 8, 9 ... protruding part

Claims (6)

[Claims] 1. A structure of a water sub-tank which is divided into a plurality of parts, and the joint surfaces of the divided parts are heat-pressed and integrated with each other to form a part which elutes when heated and joined to one of the joint surfaces of the divided parts. A structure of a water sub-tank, wherein a concave groove is provided along the joint surface for absorption. 2. The structure of a water sub-tank according to claim 1, wherein said concave groove is provided outward of a center of a joining surface. 3. The structure of a water sub tank according to claim 1, wherein said concave groove is provided near a center of a joining surface. 4. The structure of a water sub-tank according to claim 1, wherein a cutout is formed in an outer peripheral portion of the other joint surface outside a position facing the concave groove. 5. The structure of the water sub-tank according to claim 2, wherein a concave groove is further provided on the inner side in addition to the concave groove on the outer side. 6. The structure of a water sub-tank according to claim 1, wherein a cross-sectional shape of said groove is one of a semicircle and a triangle.