JPS59109791A - Method to joint two parts made of the same synthetic resin constituting heat exchanger - Google Patents

Abstract

PURPOSE:To heighten the reliability in a heat exchanger, by preventing air-tight and liquid-tight performances in a jointed area from lowering because bubbles are produced in this area, by forming a fitting groove in the bottom of a recessed groove which is provided on the outer periphery at the foot of a short cylinder, a little separated from the short cylinder, over the full length of a recessed groove, and by fitting the part of an annular body into the fitting groove. CONSTITUTION:An annular body 11 is heated by energizing a high frequency induction coil, and the jointed part is cooled to be solidified after part of a part 7 and resin on the inside of a recessed groove 10 are melted. Part of an annular body 11 is fitted into a fitting groove 15 which is provided on the bottom of a recessed groove 10, being located a little separated from the outer periphery at the foot of a short cylinder 9. With such an arrangement, a gap 16 is provided between the internal periphery of an annular body 11 and the outer periphery of a short cylinder 9, while a gap 17 is provided between the outer periphery of an annular body 11 and the inside of a recessed groove 10 on the side of external periphery.

Description

[Detailed Description of the Invention] (+ Shibayashi Field) This invention is applicable to heat exchangers such as a synthetic resin tank and a synthetic resin valve body in a heat exchanger that can be used as a heater core for a car heater, for example. This invention relates to an improvement in a method of joining synthetic resin parts that constitute an exchanger.

(Background technology) For example, as shown in Fig. 1, a heat exchanger used as a heater core has a synthetic resin material at the lower end of a core part 3 consisting of a large number of fins 1.1 and through pipes 2, 2. A lower tank 4 is provided, and the two wheels are also provided with an upper tank 5 made of synthetic resin. The upper tank 5 is provided with an inlet pipe (or outlet pipe) 6 and a circular valve body 7 that also serves as the outlet pipe (or inlet pipe). When used as a heater core to heat air, hot water is sent from the inlet pipe 6 into the upper tank 5, and this hot water is sent into the lower tuck 4 through a part of the liquid passage pipe 2, and then into the lower tank. 4, returns to the tank 5 through the remaining liquid passage pipe 2, and is discharged through the valve body 7. To adjust the degree of heating of the air,
A lever 8 provided on the valve body 7 is rotated to swing a butterfly valve inside the valve body 7, thereby changing the hot water passing area of the valve body 7 and changing the amount of hot water sent to the core part 3.

By the way, in the heat exchanger configured and operated in this way, when the valve body 7 for adjusting the amount of hot water is fixed to the upper tank 5,
Conventionally, bolts and pads were used, and the fluid tightness between both members 7.5 was maintained by an O-ring.

However, fixing the valve body 7 to the tank 5 in this way increases the number of parts required, makes the assembly work troublesome, and the O-ring is relatively expensive, as well as the heat exchanger. Production costs will increase.

In order to eliminate such inconveniences, the present inventor first invented a method for easily joining synthetic resin parts without using O-rings (Japanese Patent Application No. 16867/1986).
No. 0). In this method, as shown in FIG. 2, a short cylindrical part 9 is formed on the outer wall trj of a tank 5 made of synthetic resin, and a short cylindrical part 9 is formed on the outer periphery of the base of the short cylindrical part 9. A ring body 11 made of ferromagnetic metal material is installed inside the gate structure 10.
After inserting the tank 5 and the valve body 7, which is made of a rotating material and has a circular tube shape, it is fitted onto the short round part 9, and the high frequency induction coil 12 provided near the ring body 11 is energized to close the ring body. This heat generation melts the resin around the ring body 11, that is, the melted part 13 at the lower end of the valve body and the inner surface of the gate structure 10, and the resin eluted from the melted part 13 flows into the groove 10. The resin flows into the groove 10 and mixes with the resin eluted from the inner surface of the groove 10.
After cooling and solidifying, the tank 5 and the valve body 7 are joined in a liquid-tight manner. Further, the excess resin (extremely small M) that does not fit into the groove 10 enters between the lower surface of the flange portion 14 and the outer wall surface of the tank, where it cools and solidifies, thereby bonding both surfaces.

Note that the sum of the volume of the molten part 13 and the volume of the annular body 11 should be slightly larger than the volume of the groove 10, and furthermore, in order to stably connect the tank 5 and the valve body 7, , the diameter of the ring body 11 is about half the radius W of the groove 10,
The depth D of 0 and the height H of the fused portion 13 are formed to be approximately equal, and the width W of the fused portion 13 is formed to be a little smaller than the width W of the groove 10 (for example, about w - heat W). In addition, the valve body 7
The inner diameter (usually about 20 m/m) is slightly smaller than the outer diameter of the short cylindrical part 9 (for example, about 0.1 to 0.2 m/m).
It is formed large so that the valve body 7 can be easily fitted onto the short cylindrical part 9 when the valve body 7 is joined to the tank 5.

However, the bonding method of the previous invention configured as described above still has the following disadvantages. That is,
When the annular body 11 generates Joule heat in the groove 10 and melts the surrounding synthetic resin, bubbles are generated in the molten resin, but as shown in FIG. When the resin comes into contact with the outer circumferential surface of the base, the molten resin containing bubbles enters the gap between the outer circumferential surface of the short cylindrical portion and the inner circumferential surface of the valve body 7, hardens within this gap, and closes the gap. This will reduce the airtightness and liquidtightness of the area.

In order to prevent the synthetic resin containing air bubbles from entering the gap between the short cylindrical part and the valve body and hardening, the inner peripheral surface of the ring body 11 and the outer peripheral surface of the short cylindrical part 9 must be Is it effective to provide a gap of 1 minute between the ring body 11 and the ring body 11?
When inserting into the concave groove IO, a part of the inner circumferential surface of the ring body 11 comes close to the outer circumferential surface of the short cylindrical part 9, which prevents the air-tightness and liquid-tightness of this part from decreasing W. Can not.

(Objective of the present invention) The present invention constitutes a heat exchanger that can prevent the above-mentioned air bubbles at the joints and decrease in liquid tightness to obtain a highly reliable heat exchanger. The purpose is to provide a method for joining synthetic resin parts.

(Structure of the present invention) The method of joining the synthetic resin parts constituting the heat exchanger of the present invention is an improvement of the joining method according to the previous invention as described above. A fitting groove extending over the entire length of this concave groove lO is formed at a portion slightly away from the short cylindrical portion 9 on the bottom surface of the gate structure 10 provided on the outer periphery of the base of the short cylindrical portion 9 in order to insert the ring. By fitting a portion of the body 11 into this fitting groove, a portion of the ring body 11 is prevented from coming close to the outer peripheral surface of the short cylindrical portion 9 during welding work.

(Embodiments of the present invention) Next, the present invention will be explained in more detail while explaining the illustrated embodiments.

FIG. 3 is an enlarged sectional view corresponding to section B in FIG. 2, showing the process of joining the synthetic resin tank 5 and the valve body 7 by the method of the present invention. At the part of the tank 5 where the valve body 7 is to be attached, there is a short cylindrical part 9 that communicates the inside and outside of the tank 5.
is formed □, and this short cylindrical part 9 is formed on the outer surface of the tank 5.
An annular groove 10 is formed at the base of the holder. A fitting groove 15, which is further recessed than the groove 10, is located at a portion slightly away from the outer peripheral surface of the short cylindrical portion 9 on the bottom surface of the groove 10.
It is formed over the entire length of 0. □Annular body made of ferromagnetic metal material (iron, ferromagnetic metal, and alloys thereof) inserted into the groove 10 (the cross-sectional shape is not limited to the square shown in the figure, and may be rectangular or circular). The lower end of the ring body 11 is fitted into the fitting groove 15, and there is a ring gap 16 between the outer peripheral surface of the base of the short cylindrical part 9 and the inner peripheral surface of the ring body 11. An annular gap 17 is formed between the outer circumferential surface of the groove 10 and the outer circumferential inner surface of the groove 10 . The other constituent parts and the relationship in size of each part are the same as in the case of the previous invention described above.

'' The operation for joining the tank 5 and the valve body 7, which are configured as a series, is the same as in the case of the previous invention shown in FIG. That is, as shown in FIGS. 2 and 3, with the groove 10 on the outer wall of the tank opened upward, the ring body 11 is inserted into the groove lO and fitted into the fitting groove 15. Next, the valve body 7 is fitted onto the short cylindrical portion 9, and the lower end surface of the fused portion 13 at the lower end of the valve body 7 is brought into contact with the ring body 11. Next, when the high-frequency induction coil 12 is energized, an induced current is induced in the annular body 11 and the annular body 11 generates Joule heat, which melts the synthetic resin around the annular body 11, that is, the melted part 13 at the lower end of the valve body and the groove 10.
Melt the inside of the body. Of the synthetic resin melted in this way, the synthetic resin eluted from the molten part 13 at the lower end of the valve body flows into the groove 10 and mixes with the synthetic resin eluted from the inner surface of the groove 10, so that it is cooled and solidified. After that is the tank and valve body 7
and are liquid-tightly joined. Further, the excess synthetic resin that does not fit into the groove 1o enters between the lower surface of the flange portion 14 and the outer wall surface of the tank, cools and solidifies, and then adheres both surfaces. Same as in case. In this way, when generating heat in the ring body 11 to melt the surrounding synthetic resin,
The bubbles generated in the molten resin are separated from the resin within the gaps 16 and 17 formed on the inner and outer circumferential sides of the ring body, and are separated from the resin in the gaps between the valve body 7 and the short cylindrical portion 9 or Because it is discharged through the gap between the lower surface of the flange 14 and the outer wall of the tank,
After the resin cools and hardens, no air bubbles remain in the joint, and the joint remains airtight and liquid-tight.

In addition, in the above-mentioned embodiment, the case where a synthetic resin tank and a synthetic resin valve body are joined is shown.
The method of joining synthetic resin parts of the present invention is not limited to such parts, but can also be used for joining other parts. For example, when joining a synthetic resin seat plate and a synthetic resin tank by the joining method of the present invention, a vertical wall-shaped cylindrical portion is formed on the upper surface of the seat plate near the outer periphery, and the outer periphery of this cylindrical portion is further increased. Concave groove l for inserting the ring body 11 into the recessed part
O, and a fitting groove 15 may be provided at the bottom of this groove 10.

(Effects of the present invention) Since the method of joining the synthetic resin parts constituting the heat exchanger of the present invention is configured and operates as described above, it is possible to prevent defects from occurring in the joint due to air bubbles generated during joining. This can be effectively prevented and a highly reliable heat exchanger can be obtained.

[Brief explanation of the drawing]

Figure 1 is a front view of the heat exchanger equipped with a valve body, and Figure 2 is an enlarged view of the state in which the first connection method is implemented, with section A in Figure 1 rotated 90 degrees counterclockwise. FIG. 3 is an enlarged sectional view corresponding to section B in FIG. 2 showing an embodiment of the present invention. fin, 2 liquid pipes, 3: core, 4: lower tank, 5
・Upper tank, 6: Inlet pipe, 7: Valve body, 8 Nilever, 9:
Short cylindrical part, 10: Concave groove, 11: Annular body, 12 Two high frequency induction coils, I3: Melting part, 14: Flange part, 15: Fitting groove, 16.17° gap. Patent Applicant: Japan Radiator Co., Ltd. 1st Representative Kinzo Koyama (and 1 other person)

Claims (1)

[Claims] Two synthetic resin parts that form part of the heat exchanger (
5) A method for airtightly joining (7) to a power source, in which a short cylindrical part (9) is formed on the wall of one part (5) through which it can be passed inside and outside the part (5), and this short tube part (9) is formed on the wall of one part (5). A ring made of a ferromagnetic metal material (
After inserting 11), insert 1 with the same material as the other part (5).
．． )-shaped other part (7) is fitted onto the short cylinder part (9), and a high-frequency induction coil (
12) to generate heat in the annular body (11), which melts the resin in a part of the one component (7) and the inner surface of the groove (10), and then cools and solidifies the heat exchanger. In the method of joining synthetic resin parts together, a fitting groove (15) provided at the bottom of the groove (10) at a portion slightly away from the outer circumferential surface of the base of the short cylindrical portion (9) is provided. By fitting a part of the ring body (11), the inner peripheral surface of the ring body (11) and the short cylindrical part (
9), and a gap (17) between the outer circumferential surface of the ring body (II) and the outer circumferential inner surface of the groove (10).
) The bonding strength between the synthetic resin parts that make up the heat exchanger is 1 person.