JP4658905B2 - Reservoir tank and molding method thereof - Google Patents

Description

  The present invention relates to a reservoir tank that stores hydraulic fluid to be supplied to a hydraulic master cylinder and a molding method thereof, and more specifically, a reservoir tank in which a cap is attached to a reservoir body formed of synthetic resin with a screw and molding thereof Regarding the method.

Conventionally, in the case where a cap is attached to the upper opening edge of a synthetic resin reservoir body, the screw is inserted into a screw mounting hole provided in the cap, and the female screw portion or nut provided in the screw insertion portion formed in the reservoir body is A cap is attached to the reservoir body by screwing the front end side of the screw (see, for example, Patent Document 1).
Japanese Utility Model Publication No.4-2153

  However, in the above-described reservoir tank, when the reservoir body is molded, the portion where the screw insertion portion is provided becomes thick, and there is a possibility that sink marks may occur. In particular, in the above-described reservoir tank, since the bracket for mounting the vehicle body is formed in the portion provided with the screw insertion portion, the portion provided with the screw insertion portion becomes thicker and easily causes sink marks. It was. In order to prevent this sink, some of the reservoir body corresponding to the screw insertion part has a groove formed on the side surface. However, it does not look good and the design is lowered, and dirt may accumulate in the groove. there were.

  Accordingly, an object of the present invention is to provide a reservoir tank that can prevent the occurrence of sink marks and can be molded satisfactorily and is excellent in design, and a molding method thereof.

To achieve the above object, according to the present invention, a reservoir body is formed by inserting a cap that closes a liquid storage chamber of a reservoir body at a top opening edge of a synthetic resin reservoir body, and a screw inserted through a screw mounting hole provided in the cap. In the reservoir tank screwed and attached to the nut provided in the reservoir body, the wall thickness of the reservoir body is the same as the wall thickness of the side wall of the reservoir body, and the outer diameter of the nut A large screw insertion portion projecting from the upper end to the lower end of the reservoir body, and a screw insertion hole is formed through the screw insertion portion in the vertical direction, and the nut mounting groove is formed in the middle portion of the screw insertion portion in the vertical direction. the Ru Tei characterized in that formed in the horizontal direction by crossing the screw insertion hole so as to form by opening the outer surface of the side wall of the reservoir body.

Further, the present invention provides the reservoir body with a screw inserted into a screw mounting hole provided in the cap in order to attach a cap for closing the reservoir chamber of the reservoir body to the upper opening edge of the reservoir body made of synthetic resin. Cavity formed by a plurality of molds including a male body that forms the reservoir chamber side of the reservoir body and a female mold that forms the outer surface of the reservoir body. in the molding process of the reservoir tank according to the invention for molding by injecting a resin, the male outer surface over the upper end of the reservoir body to the lower end groove large screw insertion portion forming portion than the outer diameter of the nut a recessed, to protrude in the vertical direction intermediate portion to the female first core from the side of the screw insertion hole forming portion to form the direction of the nut mounting groove intersecting a plate-like of the screw insertion hole forming portion Together with the to the screw insertion hole forming portion and the screw insertion hole forming portion corresponding to the position of the female in the male, from the pin of the same diameter to form a screw insertion hole in the center of the screw insertion portions formed part respectively projecting a second core on the same axis made, that injecting the resin into the distal end surface of the second core said first said cavity at each of the upper and lower surfaces while being contact of the core It is characterized by.

  According to the present invention, since the portion that forms the screw insertion portion does not become thicker than the other portion of the reservoir body, it is possible to obtain a good synthetic resin reservoir tank with a simple structure and no sink. it can. Further, the side surface of the reservoir body can be formed in a substantially flat shape only by forming a nut mounting groove, so that a clean appearance can be obtained and design can be improved.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 is a sectional view taken along the line II in FIG. 4, FIG. 2 is a sectional view taken along the line II-II in FIG. 5, FIG. 3 is an enlarged sectional view of the main part of the reservoir tank, FIG. 6 is a side view, FIG. 7 is an explanatory view showing the use state of the reservoir tank, FIG. 8 is a cross-sectional side view for explaining the molded state of the reservoir body, and FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. .

  As shown in FIG. 7, the reservoir tank 1 according to this embodiment is attached to a master cylinder 11 used in a brake device 10 for a rear wheel of a bar handle vehicle, and has an upper opening edge of a reservoir body 2 made of synthetic resin. A cap 4 is attached to 2 a using screws 3 and 3.

  The reservoir body 2 is formed in a rectangular parallelepiped box shape whose upper side is opened by opposed short side walls 2b, 2b, long side walls 2c, 2c, and a bottom wall 2d, and a liquid storage chamber 5 for storing hydraulic fluid is formed therein. The Screw insertion portions 2e and 2e larger than the outer diameter of the nut 6 project from the short side walls 2b and 2b on the liquid storage chamber side, and screw insertion holes 2f and 2f are formed vertically at the screw insertion portions 2e and 2e. It penetrates in the direction. A mounting groove 2g of a nut 6 that is screwed into the screw 3 is opened at the intermediate portion in the vertical direction of each screw insertion portion 2e and opens to the outer surface of the short side walls 2b, 2b, and crosses the screw insertion hole 2f in the horizontal direction. Each is formed.

  The mounting groove 2g is arranged at a position where the internal thread formed on the inner peripheral surface of the nut 6 is continuous with the screw insertion hole 2f when the nut 6 is mounted by contacting the inner wall of the innermost groove of the mounting groove 2g. The dimension between the inner surfaces of the upper and lower walls is set substantially equal to the thickness of the nut 6. Furthermore, locking projections 2h are provided on both side walls at positions where the nut 6 is in contact with the outer surface of the nut 6 in a state where the nut 6 is mounted in the innermost portion. When the nut 6 is mounted in the mounting groove 2g from the opening of the mounting groove 2g, the locking projection 2h is elastically deformed by the press contact of the peripheral surface of the nut 6, and the nut 6 is locked. The size of the nut 6 mounted in the innermost part of the nut 6 is elastically restored to the original shape, and can be pressed into the mounting groove 2g until it contacts the inner wall of the mounting groove 2g. When the projecting portion 2h abuts, the nut 6 is held at the innermost portion to prevent the nut 6 from coming off.

  In addition, thin two level detection windows 2i and 2i that allow the amount of hydraulic fluid to be visually recognized are formed on the two opposing corner surfaces of the reservoir body 2, and the level detection windows 2i and 2i are not provided. A bracket 2j for mounting a vehicle body protrudes from the short side wall 2b of the corner portion, and a protruding pipe portion 2k for connecting a hose for supplying hydraulic fluid to the master cylinder 11 is provided on the bottom wall 2d of the other corner portion. Is formed.

  The cap 4 is made of a metal such as an aluminum alloy, closes the liquid storage chamber 5 of the reservoir body 2, and has a rectangular shape in plan view that can be polymerized on the upper opening edge 2a. Screw mounting holes 4a and 4a are formed at positions corresponding to the screw insertion holes 2f and 2f formed in the reservoir body 2.

  As shown in FIG. 7, the reservoir tank 1 formed in this way has a flange 7 of the diaphragm 7 on the upper opening edge 2 a of the reservoir body 2 in a state where the working fluid is stored in the liquid storage chamber 5 of the reservoir body 2. The parts 7a and the cap 4 are overlapped, and the screws 3 and 3 inserted through the screw mounting holes 4a and 4a of the cap 4 are inserted into the screw insertion holes 2f and 2f of the reservoir body 2, respectively. Are screwed onto the nuts 6 and 6, whereby the cap 4 and the diaphragm 7 are assembled together. The reservoir tank 1 is attached to the vehicle body via a bracket 2j, and a hose 12 connected to the hydraulic fluid supply pipe 11a of the master cylinder 11 is connected to the protruding pipe portion 2k.

  In the master cylinder 11, a cylinder body 11b is opened at a lower tip side to form a cylinder hole 11c, and a piston 13 is movably inserted in the cylinder hole 11c. A push rod 15 pivotally attached to a brake pedal 14 serving as a brake operator is movably disposed on the distal end side of the cylinder hole 11c, and the piston 13 is supported on the push rod 15. A hydraulic chamber 16 is defined between the bottom wall of the cylinder hole 11c and the piston 13, and the hydraulic fluid supply pipe 11a is provided on one side of the peripheral wall of the cylinder body 11b. The hydraulic fluid can be supplied from the reservoir tank 1 into the cylinder hole 11c.

  Next, a method for forming the reservoir body 2 will be described with reference to FIGS. The reservoir body 2 is formed by combining a plurality of molds including a male mold 20a that forms the liquid storage chamber 5 side (inner surface) of the reservoir body 2 and a female mold 20b that forms the outer surface of the reservoir body 2. Resin is injected into the cavity 21 of the mold 20 and molded.

  A screw insertion portion forming portion 20c for forming a screw insertion portion 2e larger than the outer diameter of the nut 6 from the upper end to the lower end of the reservoir body 2 is formed on each short side outer surface of the male mold 20a in the vertical direction. Each groove is recessed. Further, a plate for forming a mounting groove 2g of the nut 6 in a direction crossing the screw insertion hole forming portion 20c on the side surface of the female mold 20b facing the intermediate portion in the vertical direction of the screw insertion portion forming portion 20c. Each of the first cores 22 has a protruding shape.

  Further, the central portion of the screw insertion portion forming portion 20c is located at the center portion of the screw insertion portion forming portion 20c in the male die 20a and the position corresponding to the central portion of the screw insertion portion forming portion 20c of the female die 20b. Second cores 23a and 23b made of pins of the same diameter for forming the screw insertion holes 2f project on the same axis, and the outer peripheral surfaces of the second cores 23a and 23b and screw insertions. A space for forming the screw insertion portion 2e is formed between the inner peripheral surface of the portion forming portion 20c. The protruding lengths of the second cores 23a and 23b are such that the lower end surface of the second core 23a and the upper end surface of the second core 23b respectively contact the upper and lower surfaces of the first core 22 during mold clamping. It is formed to touch.

  Resin is injected into the cavity 21 formed by combining the molds including the male mold 20a, the female mold 20b, the first core 22 and the second cores 23a and 23b formed as described above, and the male mold 20a and the female mold 20a. The reservoir body 2 having the above-described structure is formed by opening the mold 20b and extracting the first core 22 and the second cores 23a and 23b.

  As described above, the reservoir tank according to the present embodiment is provided with the screw insertion portion extending from the upper end to the lower end of the tank body, and the screw insertion hole is provided so as to penetrate the screw insertion portion in the vertical direction. Since the thickness of the part is substantially the same as the thickness of the reservoir body, only the periphery of the screw insertion part will not be thick, so the reservoir tank is made of synthetic resin and has a simple structure and no sink marks. Can be obtained. Further, the side surface of the reservoir body can be formed in a substantially flat shape only by forming the nut mounting groove, so that the appearance is neat and the design can be improved.

  Note that the reservoir tank of the present invention is not limited to a rectangular parallelepiped box shape as in the above-described embodiment, but can be applied to a cylindrical reservoir tank. Further, the present invention is not limited to the one applied to the rear wheel brake device as in the above-described embodiment, but can also be used for a synthetic resin reservoir tank assembled to a master cylinder used in the front wheel brake device.

It is II sectional drawing of FIG. It is II-II sectional drawing of FIG. It is a principal part expanded sectional view of the reservoir tank which shows one example of this invention. It is a front view of a reservoir tank similarly. It is also a plan view. It is a side view similarly. It is explanatory drawing which similarly shows the use condition of a reservoir tank. It is a cross-sectional side view for demonstrating the shaping | molding state of a reservoir main body. It is IX-IX sectional drawing of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Reservoir tank, 2 ... Reservoir main body, 2a ... Upper opening edge, 2b ... Short side wall, 2c ... Long side wall, 2d ... Bottom wall, 2e ... Screw insertion part, 2f ... Screw insertion hole, 2g ... Mounting groove, 2h ... Locking projection, 2i ... level detection window, 2j ... bracket, 2k ... projecting tube, 3 ... screw, 4 ... cap, 4a ... screw mounting hole, 5 ... liquid storage chamber, 6 ... nut, 7 ... diaphragm, DESCRIPTION OF SYMBOLS 10 ... Rear wheel brake device, 11 ... Master cylinder, 11a ... Hydraulic fluid supply pipe, 11b ... Cylinder body, 11c ... Cylinder hole, 12 ... Hose, 13 ... Piston, 14 ... Brake pedal, 15 ... Push rod, 16 ... Hydraulic chamber, 20 ... mold, 20a ... male, 20b ... female, 20c ... screw insertion part forming part, 21 ... cavity, 22 ... first core, 23a, 23b ... second core

Claims (2)

At the upper opening edge of the reservoir body made of synthetic resin, a cap for closing the reservoir chamber of the reservoir body was attached by screwing a screw inserted into a screw mounting hole provided in the cap into a nut provided in the reservoir body. In the reservoir tank, a screw insertion portion having a wall thickness on the inner side of the reservoir body of the reservoir body that is the same as the wall thickness of the reservoir body and larger than the outer diameter of the nut is provided at the lower end from the upper end of the reservoir body. A screw insertion hole is formed through the screw insertion portion in the vertical direction, and a nut mounting groove is formed on the outer surface of the side wall of the reservoir body in the middle portion of the screw insertion portion in the vertical direction. And a reservoir tank formed in a horizontal direction so as to cross the screw insertion hole . In order to attach a cap that closes the reservoir chamber of the reservoir body to the upper opening edge of the synthetic resin reservoir body, a screw inserted through a screw mounting hole provided in the cap is screwed into a nut provided in the reservoir body. The reservoir body of the reservoir tank to be attached is injected into a cavity formed by a plurality of molds including a male mold that forms the reservoir chamber side of the reservoir body and a female mold that forms the outer surface of the reservoir body. The reservoir tank molding method according to claim 1 , wherein a screw insertion portion forming portion larger than the outer diameter of the nut is recessed in a groove shape on the outer surface of the male mold from the upper end to the lower end of the reservoir body, thereby projecting the plate-shaped first core forming the direction of the nut mounting groove intersecting the screw insertion hole forming portion of the female side of the vertically intermediate portion of the screw insertion hole forming portion, the In a screw insertion hole forming portion and the screw insertion hole forming portion corresponding to the position of the female in the mold, during the second consisting of a pin of the same diameter to form a screw insertion hole in the center of the screw insertion portions formed part Resin is injected into the cavity in a state in which the cores are respectively projected on the same axis, and the tip surface of the second core is in contact with the upper and lower surfaces of the first core, respectively. Reservoir tank molding method.

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