JPH07227918A - Molded article and its manufacture - Google Patents

Abstract

PURPOSE:To form with high accuracy a non-deformable spiral undercut channel on the outer peripheral face of a molded article by a method wherein a hollow body on which a cut slot with a width being at least the width of the recessed channel and the same direction is formed, is fixed integrally on the outer periphery of a cylindrical body wherein a recessed channel is formed in the long direction of the outer peripheral face under a condition where the recessed channel and the cut slot are communicated with each other. CONSTITUTION:A cut slot 2 formed on the outer peripheral face of the hollow body 1 and a recessed channel 8 formed on the outer peripheral face of a cylindrical body 7 are formed in such a way that both directions and pitches are the same and both are piled up one above another. In addition, the width (b) of the recessed channel 8 is formed to be wider than the width (a) of the cut slot 2. A cylindrical body 7 is inserted into the hollow body 1 thus formed in such a way that the cut slot 2 and the recessed channel 8 are piled up one above another and both the hollow body 1 and the cylindrical body are integrally bonded by using an adhesive means. A rotor 14 having bearing parts 3 and 9 on its both ends and a spiral undercut channel 13 in the long direction of the outer peripheral face is obtd. thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article having a groove, particularly a spiral groove, on its surface, such as a rotor of an agitator in an electric vacuum cleaner, and a method for producing the same.

[0002]

2. Description of the Related Art A conventional molded product and its manufacturing method will be described with reference to FIGS. 6 to 8 by taking a rotor for an agitator of an electric vacuum cleaner as an example.

In the longitudinal direction of the surface of the rotor 18 of the agitator 17 shown in FIG. 6, as shown in FIG. 7, the width of the opening 19 is narrower than that of the inside 20, and the groove 21 has a sectional shape.
A groove having a so-called convex cross section (hereinafter referred to as an undercut groove) is formed in a spiral shape, and a brush blade 22 made of a flexible material such as rubber is provided in the undercut groove 21. The thick portion formed on the base is fitted and held (see FIG. 7).

At both ends of the rotor 18, as shown in FIG. 8, a pulley 23 to which the rotation of a driving unit such as a motor is transmitted via a belt and a rotor 18 are freely rotatable with respect to the floor suction port body. A bearing portion having a shaft 24 and the like which is axially supported is formed.

In this case, the rotor 18 is formed into a rod-shaped body having an undercut groove 21 on the surface by so-called profile extrusion molding, and at that time, the extrusion die is rotated at the outlet of the molding body of the molding apparatus. The undercut groove 21 is formed in a spiral shape in the longitudinal direction by imparting a twist to the rod-shaped body (see Japanese Patent Publication No. 2-12567). In the molding of the rotor 18, the extrusion molding means is used because it has a spiral undercut groove 21 in the longitudinal direction of the outer peripheral surface thereof, and other molding means do not use a mold template. This is because the spiral undercut groove 21 cannot be formed.

[0006]

A conventional molded article having an undercut groove is formed by using a deformed mold as described above and extruding while molding the deformed mold. Therefore, it is suitable for molding a continuous rod-shaped molded product having the same cross-sectional shape, but in the case of a molded product having a plurality of portions having different cross-sectional shapes, such as the rotor for an agitator in the vacuum cleaner described above, , If there are bearings at both ends and the cross-sectional shapes of both ends and the central part are different and the overall cross-sectional shape is not the same, multiple parts with different cross-sectional shapes are molded at the same time. It will be impossible. In this case, regarding the shape of the bearing portions at both ends, it is necessary to form the rod-shaped body and then process the both end portions by post-processing such as cutting to form the bearing portion. There was a problem that the process of was complicated.

In addition, in order to form a spiral undercut groove, when it is necessary to give a twist to the rod-shaped body, the formed rod-shaped body may be twisted while being rotated by an extrusion die or the like. It becomes necessary, and therefore the molding speed is lowered, or it is difficult to maintain the rod-shaped body straight in the longitudinal direction, that is, it becomes difficult to maintain so-called straightness, and deformation of the undercut groove is likely to occur, Further, there is a problem that it becomes difficult to maintain the accuracy of the sectional shape.

Further, in the molded product thus obtained, when the straightness is not maintained and the undercut-like groove is deformed, this is caused by, for example, a rotor for an agitator of a vacuum cleaner. When it is used in a rotating body, there is a problem that runout easily occurs.

Further, when molding by extrusion molding,
It becomes difficult to form a hollow chamber in the thick part of the center of the molded product to reduce the weight, and the resin material applicable to extrusion molding has low fluidity, and only synthetic resins with high rigidity are targeted, It is impossible to use any kind of synthetic resin as a molding material, and as a result, there is a problem that the molded product is limited in terms of physical properties, application range and the like.

The present invention makes it possible to easily maintain the accuracy of the shape even in the case of a molded product having a different cross-sectional shape, and to be used as a rotating body which is easy to maintain the straightness and has no runout. The purpose of the invention is to provide a molded product having an uncut undercut groove on the outer peripheral surface, and by molding by injection molding, the range of synthetic resins that can be used as a material is expanded. It is an object of the present invention to provide a method for producing a molded product, which facilitates molding and formation of an undercut groove, and can improve the physical properties of the molded product and expand the range of application.

[0011]

In order to achieve the above object, in the molded article of the present invention, the outer periphery of the cylindrical body having a groove formed in the longitudinal direction has a width narrower than that of the groove. In addition, a hollow body having a notch formed in the same direction is integrally fixed in a state where the groove and the notch are communicated with each other to form an undercut groove on the outer peripheral surface.

Further, the concave groove and the notch are formed in a spiral shape in the longitudinal direction of the outer peripheral surface of the cylindrical body and the hollow body at the same pitch to form a spiral undercut groove on the outer peripheral surface of the molded product. Further, at least one of the cylindrical body and the hollow body may be formed by a plurality of members divided in the longitudinal direction.

In order to achieve the above object, in the method for producing a molded product according to the present invention, a cylindrical body having a groove on the outer peripheral surface in the longitudinal direction, and a width narrower than the groove and having the same longitudinal direction. Each of the hollow bodies having the notched groove is injection-molded, and then the tubular body and the hollow body are integrally fitted in a state where the recessed groove and the notched groove are overlapped and communicated with each other, thereby forming an undercut groove. A molded product having the outer peripheral surface in the longitudinal direction is manufactured.

When the molded product is manufactured as described above, if the concave groove and the notch are spirally formed at the same pitch in the longitudinal direction of the outer peripheral surface of the cylindrical body and the hollow body, the longitudinal direction of the outer peripheral surface of the molded product. It is possible to form a spiral undercut groove, and at least one of the cylindrical body and the hollow body can be formed by a plurality of members divided in the longitudinal direction.

[0015]

In the molded product constructed as described above, the undercut groove is formed by the concave groove formed on the outer peripheral surface of the cylindrical body and the notch formed in the hollow body, that is, the undercut groove is Since it is composed of two separately formed parts that are not undercut, the template at the time of molding becomes easy, and molding other than profile extrusion molding is possible.

As a result, even in the case of a molded product having a different cross-sectional shape depending on the part, it can be molded by injection molding once without requiring post-processing, and the deformation of the groove does not occur. It can be satisfactorily maintained, and when the molded product is a rod-shaped product, the straightness can be accurately maintained.

When the undercut groove is spirally formed in the longitudinal direction of the outer peripheral surface of the molded product, the groove is composed of two parts, so that the twisting step in the molding step becomes unnecessary and the molding speed is increased. It is possible to maintain the straightness accurately without any decrease in

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, a rotor for an agitator of an electric vacuum cleaner will be described with reference to FIGS.

FIG. 1 is a transverse cross-sectional view of a hollow body forming the outer peripheral portion of a rotor. Reference numeral 1 is a hollow body, 2 is a notch (width a) spirally formed in the longitudinal direction of the outer peripheral surface of the hollow body 1, Reference numeral 3 denotes a bearing portion formed at one end of the hollow body 1, and includes a pulley 4 integrally formed with the hollow body 1 and a shaft 5 having an end embedded in the hollow body 1. The hollow body 1 is made by injection molding using nylon as a material, and the bearing portion 3 is formed with a hollow portion 6 by performing hollow injection molding by gas injection.

FIG. 2 is a cross-sectional view of a cylindrical body which constitutes the inner portion of the rotor. 7 is a cylindrical body, 8 is a longitudinal direction of the outer peripheral surface of the cylindrical body 7,
A groove (width b, b> a) formed in a spiral shape and wider than the width of the slit 2 is a bearing portion formed at one end of the tubular body 7, and a shaft 11 having an end portion embedded in the tubular body 7. I have it. This cylindrical body 7 is also formed by injection molding of nylon,
The hollow portion 12 is formed by hollow injection molding by gas injection.

The notch 2 formed on the outer peripheral surface of the hollow body 1 and the concave groove 8 formed on the outer peripheral surface of the tubular body 7 are formed in a spiral shape with the same direction and pitch and overlapping each other. In addition, the width b of the groove 8 is notched.
Is formed wider than the width a of the cut groove 2
An undercut groove 13 is formed when these are overlapped.

Therefore, the hollow body 1 formed as described above
Then, the tubular body 7 is fitted so that the slit 2 and the concave groove 8 overlap each other, and both the hollow body 1 and the tubular body 7 are integrally fixed by using an adhesive or an adhesive means such as ultrasonic fusion. ,
As shown in FIG. 3, a rotor 14 having bearing portions 3 and 9 on both ends and a spiral undercut groove 13 in the longitudinal direction of the outer peripheral surface is obtained, and the undercut groove 13 is flexible. An agitator can be obtained by fitting the base portion 16 of the flexible brush blade 15 and fixing the brush blade 15 in the undercut groove 13 (see FIG. 4).

In the above description, the bearings 3 and 9 having different cross-sectional shapes from the central portion are formed at one end of the hollow body 1 and the cylindrical body 7, respectively, but as shown in FIG. It is also possible to form the bearing portions 3 and 9 at both ends of the tubular body 7 and form the hollow body 1 into a simple hollow tubular shape so that the hollow body 1 is fixed to the middle portion of the tubular body 7. In this case, the hollow body 1 needs to be formed by at least two or more members divided in the longitudinal direction as described later.

Further, in the above, the hollow body 1 or the cylindrical body 7 is used.
Has described the case of forming into a hollow shape or a cylindrical shape by one-time injection molding. However, a member having a shape divided into a plurality of pieces in the longitudinal direction at the surface including the center line of the hollow body 1 or the cylindrical body 7 is injection-molded. However, it is also possible to form a hollow shape or a cylindrical shape by combining and fixing these plural members integrally. Then, when only the hollow body 1 is composed of a plurality of members as in the case where the rotor 14 is shown in FIG. 5, the cylindrical body 7 is formed by injection molding, and the hollow body is formed on the outer peripheral surface of the cylindrical body 7. It is effective to fix and manufacture a plurality of members constituting the body 1.

Since the molded product constructed as described above is formed by integrally fixing the hollow body 1 and the cylindrical body 7 formed by injection molding, the precision of the shape of the molded product is maintained accurately. Can also be undercut groove 1
Since 3 is formed as a groove having a uniform cross-sectional shape without being deformed, the brush blade 15 can be accurately maintained, and twisting is required even when the undercut groove 13 is spirally formed in the longitudinal direction. Since it is not necessary to additionally form, the center line of the rod-shaped rotor 14 is straight, the straightness is maintained, there is no runout, and the undercut groove 13 is not deformed, and an agitator is obtained. .

Further, since the bearing portions 3 and 9 can be formed at the same time when the hollow body 1 and the cylindrical body 7 are formed, a post-processing step for forming them, which is required in the conventional case, is unnecessary, and the steps are simplified. .

Further, since the hollow body 1 and the tubular body 7 can be formed by using different synthetic resins, the hollow body 1 and the tubular body 7 can be given various characteristics. For example, the hollow body 1 If it is made of a soft synthetic resin and the cylindrical body 7 is made of a synthetic resin having strength and durability,
The outside is soft, the inside is strong and durable,
An agitator can be obtained without damaging the floor or the like.

[0028]

Since the present invention is constructed as described above, it has the following effects.

Since the undercut groove formed on the outer peripheral surface of the molded product is composed of the concave groove formed on the outer periphery of the cylindrical body and the notch formed on the hollow body, a groove without deformation can be formed. Moreover, the precision of the cross-sectional shape of the molded product is good.

Furthermore, since injection molding is possible, the straightness can be accurately maintained, and even in the case of a molded product having a non-uniform cross-sectional shape in which the cross-sectional shape varies from part to part,
It is possible to easily obtain a molded product which has a high shape accuracy and does not require post-processing and can be used for a rotating body or the like having no center runout.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a hollow body that constitutes an outer peripheral portion of a rotor for an agitator of an electric vacuum cleaner according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a tubular body that constitutes an inner portion of the rotor for an agitator.

FIG. 3 is a cross-sectional view of the agitator rotor.

FIG. 4 is a vertical cross-sectional view of a main part of the agitator rotor.

FIG. 5 is a transverse cross-sectional view showing another modified example of the agitator rotor.

FIG. 6 is a side view of an agitator of a conventional electric vacuum cleaner.

FIG. 7 is a vertical sectional view of the agitator.

FIG. 8 is a cross-sectional view of a rotor of the agitator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow body 2 Cut line 7 Cylindrical body 8 Recessed groove 13 Undercut groove

Claims (8)

[Claims] 1. A cylindrical body having a groove formed in a longitudinal direction of an outer peripheral surface thereof, and a tube fixed to an outer periphery of the cylindrical body, the width being narrower than the groove.
Also, a molded product having a hollow body in which cut lines having the same direction are formed in the longitudinal direction of the outer peripheral surface and a groove having a convex cross section formed by the concave groove and the cut lines. 2. The molded product according to claim 1, wherein the groove and the notch are formed in a spiral shape having the same pitch in the longitudinal direction of the cylindrical body and the hollow body. 3. The cylinder body is composed of a plurality of members.
Alternatively, the molded article described in 2. 4. The molded article according to claim 1, wherein the hollow body is composed of a plurality of members. 5. A cylindrical body having a concave groove in the outer peripheral surface longitudinal direction, and a hollow body having a narrower width than the concave groove and having a notch in the same direction in the outer peripheral surface longitudinal direction are respectively injection-molded, and then said A method for manufacturing a molded product, wherein the hollow body is integrally fixed to the outer periphery of a cylindrical body, and a groove having a convex cross section is formed on the surface by the concave groove and the cut line. 6. The method for producing a molded article according to claim 5, wherein the recessed grooves and the notches having the same pitch are spirally formed in the longitudinal direction of the outer peripheral surfaces of the cylindrical body and the hollow body. 7. The method for producing a molded article according to claim 5, wherein the cylindrical body is formed by a plurality of members. 8. The method for producing a molded article according to claim 5, wherein the hollow body is formed by a plurality of members.