JP7142760B1 - Hot plate welding method and fuel supply device manufacturing method - Google Patents

Abstract

An object of the present invention is to obtain a resin structure that is small in size and has high welding strength. A melting step of bringing a hot plate (81) into contact with each welding surface (2fw) to melt the surface of the welding surface (2fw), a retreating step of withdrawing the hot plate (81) from the welding surface (2fw), and welding surfaces (2fw) whose surfaces are melted. A welding step is included in which the objects to be welded are butted against each other and welded together. Before the welding step, at least one of the welding surfaces 2fw is formed into a shape that is inclined along the thickness direction Dt so as to open toward the part. [Selection drawing] Fig. 1

Description

The present application relates to a hot plate welding method and a manufacturing method of a fuel supply device.

2. Description of the Related Art Vehicles use a fuel supply device that is arranged in a fuel tank that stores fuel and that supplies the fuel in the fuel tank to the outside. A fuel supply system includes major components such as a fuel pump that discharges fuel, a fuel filter that filters the fuel discharged from the fuel pump, and a pressure regulator that adjusts the pressure of the fuel discharged from the fuel pump. Among them, the fuel pump and the fuel filter are handled as an integral unit called a filter assembly (ASSY) housed in a housing. Then, for example, in the case of a motorcycle, the filter assembly described above is supported by a support member with respect to a cover member that closes an opening provided in the bottom wall of the fuel tank.

Here, the housing of the filter assembly described above is formed of a cap and a case made of the same resin material. Specifically, after the fuel pump and fuel filter are accommodated inside the case, the case and the cap are butted against each other and joined by hot plate welding to form a partition wall with the outside and to form a fuel passage inside (for example, See Patent Document 1.).

JP 2011-117323 A (Paragraph 0019, FIGS. 1 and 2)

In addition to being exposed to fuel at all times, the fuel supply system is always used under high pressure in the fuel passage, so in addition to initial strength, long-term resistance to fuel swelling and creep is required. . However, in hot plate welding, irregularities are generated on the welding surfaces of the case and the cap, which are parts to be welded, and air may be caught in the welding interface. There is a problem that the entrapped air remains as voids in the welding interface, and this causes a decrease in welding strength (creep life). In order to ensure the welding strength, it is conceivable to increase the welding width, but in this case, there is a risk that the size of the product will increase.

The present application discloses a technique for solving the above problems, and an object of the present application is to obtain a compact resin structure with high welding strength, particularly a compact and highly reliable fuel supply device.

The hot plate welding method disclosed in the present application comprises: a melting step of bringing a hot plate into contact with each of the welding surfaces forming a pair of resin objects to be welded, and melting the surfaces of the welding surfaces forming the pair; a retracting step of retracting the hot plate from the welding surface; and a welding step of bringing the pair of welding surfaces with the melted surfaces against each other to weld the objects to be welded together. At least one of the pair of welding surfaces is arranged so that when the welding surfaces come into contact with each other, a gap formed adjacent to the contact portion opens toward either end in the thickness direction of the plate material. is formed into an inclined shape that is inclined from one end portion to the other end portion in the thickness direction before the welding step.

According to the hot plate welding method disclosed in the present application, since the welding surface is inclined, entrainment of air into the welding interface can be prevented, and a compact resin structure with high welding strength can be obtained.

FIGS. 1A to 1F are cross-sectional views showing the state of the vicinity of the welding surface of the objects to be welded at each stage for explaining the hot plate welding method according to the first embodiment. FIG. 2 is a schematic diagram showing the installation state of the fuel supply device in the fuel tank and the flow of fuel according to the first embodiment; 1 is a perspective view showing an external configuration of a fuel supply device according to Embodiment 1; FIG. 4A to 4F are cross-sectional views showing the state of the vicinity of the welding surface of the objects to be welded at each stage for explaining the hot plate welding method according to the comparative example. FIG. 4 is a graphical representation showing the relationship between tensile stress and time until creep failure of resin structures with different connection states. 1 is a flow chart for explaining a hot plate welding method according to Embodiment 1 and a method for manufacturing a fuel supply device using the same. FIG. 2 is an exploded perspective view showing the configuration of a filter assembly, which is a main component of the fuel supply system according to the first embodiment and manufactured by a hot plate welding method; 8A and 8B are a schematic diagram and a plan view of a hot plate, respectively, showing a configuration including a mold when hot plate welding the cap to the case in the manufacturing method of the fuel supply device according to the first embodiment. . 9A to 9F are cross-sectional views showing the state of the vicinity of the welding surface of the object to be welded at each stage, for explaining the hot plate welding method according to the modification of the first embodiment. FIGS. 10A to 10F are cross-sectional views showing the state of the vicinity of the welding surface of the object to be welded at each stage for explaining the hot plate welding method according to the second embodiment. FIGS. 11A to 11F are cross-sectional views showing the state of the vicinity of the welding surface of the object to be welded at each stage for explaining the hot plate welding method according to the modification of the second embodiment.

Embodiment 1.
FIGS. 1A to 1F, FIGS. 2 to 7, and FIGS. 8A and 8B show a hot plate welding method according to the first embodiment, a fuel supply device manufacturing method using the same, and the configuration and operation of the fuel supply device. 1A to 1F show the states of the portions near the welding surfaces of the case and cap, which are the objects to be welded, at each stage, perpendicular to the thickness direction of the plate material of the member and along the butting direction. 1 is a cross-sectional view along a cross-sectional plane; FIG.

FIG. 2 is a schematic cross-sectional view showing the installation state of the fuel supply device in the fuel tank and the flow of fuel, FIG. 3 is a perspective view showing the external configuration of the fuel supply device, and FIGS. 1A to 1F are cross-sectional views corresponding to FIGS. 1A to 1F, respectively showing the states of the vicinity of the welding surface of the object to be welded at each stage, for explaining the hot plate welding method according to the comparative example; FIG. Furthermore, in order to compare the strength of a resin structure such as a filter assembly, FIG. Figure 2 is a diagram in graphical form showing relationships;

6 is a flow chart showing the manufacturing process of the filter assembly for explaining the hot plate welding method, FIG. 7 is an exploded perspective view showing the structure of the filter assembly manufactured by the hot plate welding method, and FIG. In the manufacturing process of the filter assembly that constitutes the manufacturing method of the device, a schematic diagram showing the configuration including the mold when hot plate welding the cap to the case, FIG. 1 is a plan view when viewed from .

A hot plate welding method, a manufacturing method of a fuel supply device using the same, and a fuel supply device according to the first embodiment will be described below with reference to the drawings. A filter assembly as a resin structure will be described. As shown in FIG. 2, the fuel supply device 1 including the filter assembly 5 manufactured using the hot plate welding method has the cover member 3 inserted into the insertion port (opening 921) provided in the bottom wall of the fuel tank 920. is fixed and members other than the cover member 3 are accommodated in the fuel tank 920 .

As functional parts involved in the operation of the fuel supply device 1, a primary filter 4 for removing contaminants floating in the fuel 930 in the fuel tank 920, and through the primary filter 4, the fuel is sucked and pressurized. A fuel pump 51 for discharging is provided. Further, for example, a secondary filter 52 for removing contaminants in the high-pressure fuel discharged from the fuel pump 51, and discharging surplus fuel to limit the pressure of the fuel discharged from the fuel pump 51 to a limiting pressure. A pressure regulator 6 is provided to keep the

Among the functional parts, the fuel pump 51 and the secondary filter 52 are accommodated in the housing 2 configured by hot-plate welding a resin case 22 and a cap 21 to form the filter assembly 5 . A fuel passage is formed in the filter assembly 5 during hot plate welding.

On the other hand, as shown in FIG. 3, the lid member 3 forming part of the outer shape of the fuel supply device 1 includes a disk portion 3b that closes the opening 921 from the outside of the fuel tank 920, and a portion on the inner peripheral side of the disk portion. , and an annular portion 3c extending toward the inside of the fuel tank 920, forming a cylindrical shape with a bottom. Then, the filter assembly 5 is fitted into the annular portion 3c, and is held by a supporting member such as a snap fit (not labeled) so that the filter assembly 5 does not come off. At the same time, it also functions as a lid that closes the opening 921 of the fuel tank 920 and forms a flow path leading to the injector 910 . A fuel level sensor (not shown) may be provided outside the housing of the fuel supply device 1 .

Assuming the above configuration, the flow of the fuel 930 in the fuel supply device 1 will be described with reference back to FIG. After passing through the primary filter 4 , the fuel 930 pressurized by the fuel pump 51 passes through the flow path (fuel passage) inside the filter assembly 5 , passes through the secondary filter 52 , and is pressure-fed to the injector 910 . At this time, surplus fuel that is not consumed by injector 910 is returned from pressure regulator 6 into fuel tank 920 via a return passage (not labeled) branching from the passage leading to injector 910 . As a result, the fuel consuming device such as the injector 910 can be supplied with fuel 930 at a constant pressure in just the right amount.

Prior to explaining the hot plate welding method and the manufacturing method of the fuel supply device 1 for realizing the above configuration, an outline of a general hot plate welding method and its problems will be explained. In hot plate welding, the butt surfaces of the resin members to be welded are brought into contact with the surface of the hot plate heated to the softening point of the resin molded product or higher, and melted. It is a bonding method that integrates by crimping and cooling in that state.

As a comparative example, the case 22 and the cap 21, which are members to be welded when forming the housing 2 of the filter assembly 5, are formed by general hot plate welding will be described with reference to FIGS. 4A to 4F. In the figure, parts corresponding to the configuration used in the hot plate welding method of the present application, but different from the hot plate welding method of the present application are denoted by "R" at the end of the reference numerals.

In the hot plate welding, the case 22 and the cap 21 are attached to a jig (not shown), and are positioned so that the welding surfaces 22fw and the abutting surfaces to be the welding surfaces 21fw are opposed to each other with a gap. After that, as shown in FIG. 4A, a plate (hot plate 81R) heated to a softening point or higher of the member to be welded moves between the parts. Further, by bringing the case 22 and the cap 21 closer to each other and bringing the welding surface 22fw and the welding surface 21fw into contact with the hot plate 81R as shown in FIG. 4B, the temperatures of the welding surfaces 22fw and 21fw are lowered. The surface is melted by heating above the softening point.

Thereafter, as shown in FIG. 4C, the case 22 and the cap 21 are moved away from the hot plate 81R, and the hot plate 81R is withdrawn from the gap between the cap 21 and the case 22. Then, as shown in FIG. When the retraction is completed, the case 22 and the cap 21 are brought closer to each other again, and as shown in FIG. 4D, the melted welding surfaces 22fw and 21fw are brought into contact with each other. Then, as shown in FIG. 4E, when the cap 21 is pressed against the case 22, the welding surfaces 22fw and 21fw are welded. As the pressure is further applied, as shown in FIG. 4F, the contact points PbR with the outer peripheral surfaces 22fx and 21fx of the welding interface BwR move along with the burr 2bR in the thickness direction of the partition wall (plate material) between the welding surfaces 22fw and 21fw. Shows some progress towards the outside of Dt.

At this time, in the hot plate welding according to the comparative example, when the welding surface 21fw and the welding surface 22fw separate from the hot plate 81R (FIG. 4C), the welding surface 21fw and the welding surface are pulled by the surface 81fR of the hot plate 81R. Unintended unevenness 2r occurs on 22fw. By being pressed in this state, a gap GpR is formed between the welding surfaces 21fw and 22fw (FIG. 4D), and air bubbles Ba may remain in the middle portion of the welding interface Bw in the thickness direction Dt (FIG. 4E). ).

By increasing the applied pressure in the state shown in FIG. 4E, even if the movement of the contact Pb to the outside can be promoted, there is a gap GpR that does not lead to the outside, so the bubble Ba that has no escape route is trapped inside the thickness direction Dt. , and remains as a void 2v. Next, the strength of a structural material containing air bubbles inside in the thickness direction Dt will be described with reference to FIG. In the figure, the vertical axis indicates the tensile stress applied to the test piece, and the horizontal axis indicates the time until creep fracture.

As a first comparative example, C1 is a test piece in which air bubbles Ba are involved in the welding interface Bw during welding and remain as voids 2v. The resulting test piece is C2, and the seamless test piece is C3 as a reference example. Compared to the second comparative example (C2) in which the voids 2v did not remain (discovered later in the analysis), the test body in which the voids 2v remained as in the first comparative example (C1) .

Then, when a test piece is formed by hot plate welding according to the comparative example, the bonding state varies from the state like the first comparative example to the state like the second comparative example, and a structure having stable strength is formed. it was difficult to On the other hand, in the hot plate welding method of the present application, by configuring as follows, it is possible to stably form a welded resin structure while preventing the generation of the void 2v as in the second comparative example. can. Description will be made with reference to the flow chart of FIG.

Also in the hot plate welding method of the present application, first, as shown in FIG. 7, the fuel pump 51 and the secondary filter 52 are incorporated into the case 22 as preparation of the members to be welded (step S100). The prepared case 22 and cap 21 are attached to jigs 82a and 82b, respectively, as shown in FIG. 8A, and positioned so that the welding surfaces 22fw and 21fw of the respective welding surfaces are opposed to each other with a space therebetween. (Step S200), the hot plate welding method begins.

Then, as shown in FIG. 1A, a hot plate 81 heated to a temperature equal to or higher than the softening point of the member to be welded is moved between the parts in the advancing/retreating direction Dmp. Here, in Embodiment 1, as shown in FIG. 8B, the concave portion 81fc of the surface 81f of the hot plate 81, which is inclined in the butting direction Db, corresponds to the area where the welding surface 21fw and the welding surface 22fw are projected. provided all around. Although FIG. 8B does not show a cross section, hatching shows the region where the concave portion 81fc is formed.

In addition, in the drawing, for the sake of simplification, only the welding surface 22fw and the welding surface 21fw constituting the plate material portion as the partition of the housing 2 are projected onto the hot plate 81, and the concave portion 81fc is formed along one oval pattern. Although the example which formed is shown, it does not restrict to this. Needless to say, there may be a concave portion 81fc formed along a pattern of projecting the welding surface 52fw with the secondary filter 52 to form a fuel passage in the housing 2, for example. Furthermore, there may be recesses 81fc formed along a pattern of projecting a plurality of required welding surfaces, such as a pattern of projecting an open curve that is the direction in which the plate member extends including straight lines.

That is, on the surface 81f of the hot plate 81, the welding surface 22fw and the welding surface 21fw (collectively referred to as the welding surface 2fw when not distinguished) face each other. A recess 81fc is formed. Therefore, in this movement, the hot plate 81 is positioned so that the position of the formation pattern of the concave portion 81fc, which is the inclined portion, matches the curved pattern on which the welding surface 2fw is projected (step S210).

In the positioned state, the jigs 82a and 82b are moved in the vertical direction Dmd (FIG. 8) to bring the case 22 and the cap 21 closer to each other, so that the welding surfaces 22fw and 21fw are separated as shown in FIG. 1B. They are brought into contact with the concave portion 81fc of the hot plate 81, respectively. Then, the temperatures of the welding surface 22fw and the welding surface 21fw are heated to the softening point or higher, and the surface portions are melted (step S220).

When a predetermined melting state (for example, contact time management) is achieved, the case 22 and the cap 21 are moved away from the hot plate 81 as shown in FIG. 1C (step S230). Further, the hot plate 81 is moved in the advancing/retreating direction Dmp to retreat from the gap between the cap 21 and the case 22 (step S240). Then, the welding surface 22fw and the welding surface 21fw follow the concave portion 81fc and are positioned inside the respective end portions (the outer peripheral surface 21fx and the inner peripheral surface 21fi, the outer peripheral surface 22fx and the inner peripheral surface 22fi) in the thickness direction Dt. A convex portion 2p protruding is formed.

When the retraction is completed, the case 22 and the cap 21 are brought closer to each other again, and as shown in FIG. 1D, the welding surfaces 22fw whose surfaces are melted and the welding surfaces 21fw are brought into contact with each other. At this time, the protrusions 2p located in the intermediate portion first come into contact with each other with both ends (gap Gp) in the thickness direction Dt being open.

Then, as shown in FIG. 1E, when the cap 21 is pressed against the case 22, the welding surfaces 22fw and 21fw are welded. As the pressure is further applied, as shown in FIG. 1F, the points of contact Pb with the outer peripheral surfaces 22fx and 21fx of the welding interface Bw start from the convex portion 2p and follow the burr 2b in the thickness direction Dt as the partition wall (plate material). progress toward the outside of the

In other words, the contact between the welding surfaces 2fw starts from the convex portion 2p located in the middle portion in the thickness direction Dt, and ends at both ends (outer peripheral surface 2fx (outer peripheral surface 21fx, outer peripheral surface 22fx) side and inner peripheral surface 2fi (inner peripheral surface 2fx). Therefore, even if air enters the welding interface Bw, air bubbles will flow out from inside the welding interface Bw as the burr 2b extends to both ends. As a result, it is possible to stably form a structure in which the gap 2v does not remain at the weld interface Bw, as in the second comparative example. , it is possible to both ensure strength (creep resistance) and suppress product size increase.

Modification.
In the above-described embodiment, an example in which the hot plate is provided with the concave portion as an inclination in order to form the convex portion protruding in the central portion in the thickness direction on the welding surface has been described. In this modified example, an example will be described in which an inclined portion is provided in a region facing the welding surface of the hot plate so as to form an inclined surface that is inclined from one side to the other in the thickness direction of the welding surface. FIGS. 9A to 9F are for explaining a hot plate welding method according to a modification of the first embodiment, and the portions near the welding surfaces of the case and cap, which are objects to be welded corresponding to FIGS. 1A to 1F, are shown. 3 is a cross-sectional view taken along a cutting plane perpendicular to the thickness direction of the members and along the butting direction, respectively, showing states in each stage of .

In the modification, of the surface 81f of the hot plate 81, the inclined portion 81ft that is inclined in the butting direction Db is the welding surface 21fw and the welding surface 22fw of the surface 81f of the hot plate 81, similarly to the description with reference to FIG. 4B. is provided over the entire circumference with respect to the projected image of Therefore, in the movement of the hot plate 81 in the modified example as well, as shown in FIG. The hot plate 81 is positioned (step S210).

In the positioned state, the jigs 82a and 82b are moved in the vertical direction Dmd to bring the case 22 and the cap 21 closer to each other, and as shown in FIG. is brought into contact with the sloping portion 81ft. Then, the temperatures of the welding surface 22fw and the welding surface 21fw are heated to the softening point or higher, and the surface portions are melted (step S220).

When the predetermined molten state is achieved, as shown in FIG. 9C, the case 22 and the cap 21 are moved away from the hot plate 81 (step S230). Further, the hot plate 81 is moved in the advancing/retreating direction Dmp to retreat from the gap between the cap 21 and the case 22 (step S240). Then, on each welding surface 2fw, an inclined surface 2t that is inclined from one end (outer peripheral surface 2fx) to the other end (inner peripheral surface 2fi) in the thickness direction Dt following the inclined portion 81ft is formed. there is

When the retraction is completed, the case 22 and the cap 21 are brought closer to each other again, and as shown in FIG. 9D, the melted welding surface 22fw is brought into contact with the tip 21e of the welding surface 21fw and the tip 22e. At this time, while one end (outer peripheral surface 2fx) side (gap Gp) in the thickness direction Dt is open, the tip portions 21e and 22e located on the other end (inner peripheral surface 2fi) side first come into contact with each other.

Then, as shown in FIG. 9E, when the cap 21 is pressed against the case 22, the welding surfaces 22fw and 21fw are welded. As the pressure is further applied, as shown in FIG. 9F, the outer peripheral surface 21fx of the welding interface Bw and the contact point Pb on the outer peripheral surface 22fx side opposite to the front end portion 21e and the front end portion 22e move along the inclined surface 2t. , progressing outward.

That is, since the inclined surface 2t of the welding surface 22fw and the inclined surface 2t of the welding surface 21fw are formed so that the inclinations are symmetrical, one side in the thickness direction Dt is opened. As a result, the contact between the welding surfaces 2fw starts from the tips 21e and 22e located on the other end (inner peripheral surface 2fi) side in the thickness direction Dt and progresses toward the one end (outer peripheral surface 2fx) side. Become.

Therefore, even if air enters the welding interface Bw, the expansion of the burr 2b toward the (outer peripheral surface 2fx) side makes it easier for air bubbles to escape from the inside of the welding interface Bw, ensuring a predetermined welding width. can do. As a result, even in this modified example, it is possible to stably form a structure in which no gap 2v remains at the weld interface Bw, as in the second comparative example, thereby ensuring strength (creep resistance) and increasing the size of the product. It is possible to achieve both suppression.

Embodiment 2.
In the first embodiment, an example has been described in which the welding surface perpendicular to the butting direction is deformed into a shape having a convex portion or an inclined surface depending on the shape formed on the hot plates. In Embodiment 2, an example will be described in which the welding surface is formed in advance into a shape corresponding to a convex portion or an inclined surface before being deformed by a hot plate.

10A to 10F are for explaining the hot plate welding method according to the second embodiment. 3 is a cross-sectional view taken along a cutting plane perpendicular to the thickness direction of the member and along the butting direction, respectively, showing the state of . It should be noted that the configuration is the same as that of Embodiment 1 except that the shape of the welding surface is formed in advance, and the description of the same portions is omitted, and FIGS. 2 to 8 used in Embodiment 1 are used. .

Also in the hot plate welding method and the fuel supply device manufacturing method according to the second embodiment, the fuel pump 51 and the secondary filter 52 are incorporated into the case 22 as preparation of the members to be welded (step S100). Then, the case 22 and the cap 21 that have been prepared are attached to the jigs 82a and 82b, respectively, and positioned so that the welding surfaces 22fw and 21fw are opposed to each other with a gap (step S200), The hot plate welding process begins.

At this time, in the second embodiment, as shown in FIG. 10A, the welding surfaces 21fw and 22fw are formed in a convex shape in advance so that the central side protrudes from the outside in the thickness direction Dt. Further, on the surface 81f of the hot plate 81, similarly to the first embodiment, concave portions 81fc inclined in the butting direction Db are provided in portions corresponding to the curved patterns corresponding to the respective welding surfaces 2fw.

In the positioned state, the jigs 82a and 82b are moved in the vertical direction Dmd to bring the case 22 and the cap 21 closer to each other, so that the welding surfaces 2fw are brought into contact with the concave portions 81fc of the hot plate 81 as shown in FIG. 10B. Let At this time, since the welding surfaces 22fw and 21fw are formed in a convex shape in advance, the entire surfaces contact the concave portion 81fc in the thickness direction Dt. Therefore, the temperatures of the welding surface 22fw and the welding surface 21fw are uniformly heated to the softening point or higher in the thickness direction Dt, and the surface portions are melted (step S220).

Then, as shown in FIG. 10C, the case 22 and the cap 21 are moved away from the hot plate 81 (step S230), and the hot plate 81 is moved in the advancing/retreating direction Dmp so that the gap between the cap 21 and the case 22 is closed. evacuate from the part (step S240). In this case also, the welding surface 22fw and the welding surface 21fw follow the concave portion 81fc, and in the thickness direction Dt, the respective wall surfaces (the outer peripheral surface 21fx and the inner peripheral surface 21fi, the outer peripheral surface 22fx and the inner peripheral surface 22fi) are A protruding portion 2p having a protruded inner portion is formed. However, since the welding surface 22fw and the welding surface 21fw are formed in a convex shape in advance, the size of the burr 2b is smaller than that in the first embodiment.

When the retraction is completed, the case 22 and the cap 21 are brought closer to each other again so that the melted welding surface 22fw and the welding surface 21fw are brought into contact with each other as shown in FIG. 10D. Then, as shown in FIG. 10E, when the cap 21 is pressed against the case 22, the welding surfaces 22fw and 21fw are welded. As the pressure is further applied, as shown in FIG. 10F, the points of contact Pb with the outer peripheral surfaces 22fx and 21fx of the welding interface Bw extend outward in the thickness direction Dt from the protrusion 2p along with the burr 2b. do.

At this time, even if air enters the welding interface Bw, since the convex portion 2p is formed, air bubbles are easily released from the inside of the welding interface Bw as the burr 2b expands. Width can be secured. As a result, as in the second comparative example, it is possible to stably form a structure in which no gap 2v remains in the weld interface Bw portion, thereby ensuring both strength (creep resistance) and suppression of product size increase. becomes possible. Furthermore, since the generation (size) of the burr 2b is suppressed, further miniaturization can be expected.

Modification.
In this modification, as in the modification of Embodiment 1, a hot plate having an inclined portion inclined from one side to the other in a portion corresponding to the projected image of the welding surface is used, and the hot plate deforms the welding surface. An example in which the welding surface is formed in advance in a shape corresponding to the inclined surface at the previous stage will be described. FIGS. 11A to 11F are for explaining a hot plate welding method according to a modification of the second embodiment. 3 is a cross-sectional view taken along a cutting plane perpendicular to the thickness direction of the member and along the butting direction, respectively, showing states in each stage of .

In the modification of Embodiment 2, as shown in FIG. 11A, the welding surface 21fw and the welding surface 22fw are aligned with the inclined portion 81ft provided on the hot plate 81 so as to be inclined from one side to the other side in the thickness direction Dt. molded. Then, the heating plate 81 is positioned so that the position of the formation pattern of the inclined portion 81ft, which is an inclined portion, matches the projected image of the curved pattern on each welding surface 2fw (step S210).

In the positioned state, the jigs 82a and 82b are moved in the vertical direction Dmd to bring the case 22 and the cap 21 closer to each other, and as shown in FIG. is brought into contact with the sloping portion 81ft. At this time, since the welding surfaces 22fw and 21fw are formed in an inclined shape in advance in accordance with the inclined portion 81ft, the entire surfaces come into contact with the inclined portion 81ft in the thickness direction Dt. Therefore, the temperatures of the welding surface 22fw and the welding surface 21fw are uniformly heated to the softening point or higher in the thickness direction Dt, and the surface portions are melted (step S220).

When the predetermined molten state is achieved, as shown in FIG. 11C, the case 22 and the cap 21 are moved away from the hot plate 81 (step S230). Further, the hot plate 81 is moved in the advancing/retreating direction Dmp to retreat from the gap between the cap 21 and the case 22 (step S240). Then, the welding surface 22fw and the welding surface 21fw follow the inclined portion 81ft to form an inclined surface 2t inclined from one side (the outer peripheral surface 2fx side) to the other side (the inner peripheral surface 2fi side) in the thickness direction Dt. . However, since the welding surface 22fw and the welding surface 21fw are formed to be inclined in advance, the size of the burr 2b is smaller than that of the modified example of the first embodiment.

When the retraction is completed, the case 22 and the cap 21 are brought closer to each other again, and as shown in FIG. Then, as shown in FIG. 11E, when the cap 21 is pressed against the case 22, the welding surfaces 22fw and 21fw are welded. As the pressure is further increased, as shown in FIG. 11F, the contact point Pb on one side of the welding interface Bw (the side opposite to the tip portions 21e and 22e) extends outward along the inclined surface 2t.

At this time, even if air enters the welding interface Bw, since the slanted surface 2t is formed, as the burr 2b extends, air bubbles can easily escape from the inside of the welding interface Bw. Width can be secured. As a result, even in this modified example, it is possible to stably form a structure in which no gap 2v remains in the weld interface Bw portion, as in the second comparative example, thereby ensuring strength (creep resistance) and increasing the size of the product. It is possible to achieve both suppression of erosion. Furthermore, since the generation (size) of the burr 2b is suppressed, further miniaturization can be expected.

It should be noted that although the present application has described exemplary embodiments, the various features, aspects, and functions described in the embodiments are not limited to application of particular embodiments, but alone. , or in various combinations applicable to the embodiments. Accordingly, numerous variations not illustrated are envisioned within the scope of the technology disclosed herein.

For example, an example in which the recessed portion 81fc or the inclined portion 81ft is provided on both sides of the hot plate 81 has been shown, but the present invention is not limited to this, and may be provided only on one side. Furthermore, although an example has been shown in which the welding surface is formed in advance in accordance with the concave portion 81fc or the inclined portion 81ft, the welding surface may be formed only on one of them. If only one side is inclined, there is a possibility that the effect of removing air bubbles will be reduced compared to the case where both sides are inclined, but there is an advantage that the labor for processing can be saved.

Moreover, although the example which heats the welding surface 21fw and the welding surface 22fw using the hot plate 81 of 1 sheet was shown, it does not restrict to this. For example, different hot plates 81 may be used for the welding surface 21fw and the welding surface 22fw, respectively, and may be separately aligned and heated. It is possible.

Alternatively, if the surface of the welding surface 2fw can be shaped to be convex or inclined along the thickness direction Dt during melting (step S250), high-strength bonding can be achieved. Therefore, as an example that can be easily realized, an example in which the hot plate 81 is provided with the recessed portion 81fc or the inclined portion 81ft is shown, but the present invention is not limited to this. can be formed to be convex or inclined along the thickness direction Dt.

Furthermore, in the welding step (step S250), when the welding surfaces 2fw are butted against each other in a state where the surfaces are melted, the gap Gp adjacent to the first contact point is located at either end (outer circumference) in the thickness direction Dt. It suffices if it is open to the surface 2fx or the inner peripheral surface 2fi). As long as the conditions are satisfied, the shape is not limited to the exemplified convex shape (convex portion 2p) or inclined shape (inclined surface 2t).

As described above, according to the hot plate welding method according to the present embodiment, the hot plates 81 are brought into contact with the welding surfaces 2fw forming pairs of the resin objects to be welded (the cap 21 and the case 22). a melting step (steps S200 to S220) of melting the surfaces of the welding surfaces 2fw forming a pair, a retraction step of withdrawing the hot plate 81 from the pair of welding surfaces 2fw (steps S230 to S240), and a pair of welding surfaces in which the surfaces are melted A welding step (step S250) is included in which the surfaces 2fw are brought into contact with each other and the objects to be welded (the cap 21 and the case 22) are welded together. , the pair of welding surfaces so that the gap Gp formed adjacent to the contact portion opens toward either end (the outer peripheral surface 2fx side, the inner peripheral surface 2fi side) in the thickness direction Dt of the plate material. At least one welding surface (for example, welding surface 21fw) of 2fw is formed into a shape that is inclined along the thickness direction Dt before the welding step (step S250). As a result, the contact point Pb between the gap Gp and the welding interface Bw advances outward in the thickness direction Dt as the butting occurs, so that no gap remains in the welding interface Bw, and a strongly bonded resin structure can be formed. can.

In particular, at least one of the pair of welding surfaces 2fw has a convex shape (convex portion 2p ), or formed in an inclined shape (inclined surface 2t) inclined from one end to the other end in the thickness direction Dt, so that they are formed adjacent to the contact portions (the convex portions 2p, the tip portions 21e and 22e). The gap Gp is reliably opened toward one of the ends in the thickness direction Dt (the side of the outer peripheral surface 2fx, the side of the inner peripheral surface 2fi).

At this time, the surface (surface 81f) of the hot plate 81 facing one of the welding surfaces is provided with a concave portion 81fc corresponding to the convex shape (convex portion 2p) corresponding to the curved pattern on which the one welding surface is projected, or An inclined portion 81ft corresponding to the inclined shape (inclined surface 2t) is formed in a pattern, and in the melting step (step S220), one welding surface is pressed against the patterned concave portion 81fc or inclined portion 81ft, If the convex shape (the convex portion 2p) or the inclined shape (the inclined surface 2t) is formed, the convex shape (the convex portion 2p) or the convex shape (the convex portion 2p) or It can be formed into an inclined shape (inclined surface 2t).

At this time, one welding surface should be molded into a shape corresponding to a convex shape (projecting portion 2p) or an inclined shape (inclined surface 2t) before the melting process (steps S200 to S220). , the burr 2b is suppressed, and the size can be further reduced.

A step of installing a fuel pump 51 that pressurizes and discharges fuel 930 into the case 22, which is one of the objects to be welded, and a fuel filter (secondary filter 52) that removes foreign matter from the high-pressure fuel discharged from the fuel pump 51 (step S100), and the case 22 in which the fuel pump 51 and the fuel filter (secondary filter 52) are incorporated, using the above-described hot plate welding method (steps S200 to S250), the cap 21 which is the other of the objects to be welded and forming the filter assembly 5 in which the fuel pump 51 and the fuel filter (secondary filter 52) are accommodated. It is possible to obtain the fuel supply device 1 that can withstand the discharge pressure and is compact and highly reliable.

1: fuel supply device 2: housing 2fi: inner peripheral surface 2fw: welding surface 2fx: outer peripheral surface 2p: convex portion 2t: inclined surface 21: cap 21fi: inner peripheral surface 21fw: welding Surface 21fx: Outer peripheral surface 22: Case 22fi: Inner peripheral surface 22fw: Welding surface 22fx: Outer peripheral surface 3: Lid member 4: Primary filter 5: Filter assembly 51: Fuel pump 52: Secondary Next filter (fuel filter) 6: Pressure regulator 920: Fuel tank 81: Hot plate 81f: Surface 81fc: Concave portion 81ft: Inclined portion Bw: Welded interface Dt: Thickness direction Gp: Gap Pb :contact.

Claims (5)

A melting step of bringing a hot plate into contact with each of the paired welding surfaces of the resin objects to be welded to melt the surfaces of the paired welding surfaces;
a retraction step of retracting the hot plates from the pair of welding surfaces;
In the welding step, when the pair of welding surfaces are in contact with each other, the pair of welding surfaces is arranged such that a gap formed adjacent to the contact portion opens toward either end in the thickness direction of the plate material. A hot plate welding method, wherein at least one of the welding surfaces forming the . Before the welding step, the other welding surface of the pair of welding surfaces has an inclined shape that is inclined from one end to the other end in the thickness direction so that the inclination is symmetrical with the one welding surface . 2. The hot plate welding method according to claim 1, wherein the plate is molded. At least a surface of the hot plate facing the one welding surface is formed with an inclined portion corresponding to the inclined shape corresponding to a curved pattern obtained by projecting the one welding surface,
3. The hot plate according to claim 1, wherein in the melting step, the one welding surface is pressed against the pattern-formed inclined portion to form the inclined shape. Welding method. 4. The hot plate welding method according to claim 3, wherein at least one of said welding surfaces is formed into a shape corresponding to said inclined shape before said melting step. a step of installing a fuel pump that pressurizes and discharges fuel into a case that is one of the objects to be welded, and a fuel filter that removes foreign matter from the high-pressure fuel discharged from the fuel pump; and A cap, which is the other of the objects to be welded, is welded to the incorporated case by using the hot plate welding method according to any one of claims 1 to 4, and the fuel pump and the fuel filter are provided inside. forming a filter assembly containing
A method of manufacturing a fuel supply device, comprising:

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