JP2001150498A - Method for molding article having toothed part on surface, method for molding gear, double helical gear as well as method and apparatus for molding double helical gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for molding component having engaging part such as double helical gear or the like with a resin material. SOLUTION: The method for molding an article having a toothed part on the surface comprises the steps of forming a cavity for molding the article from a fixed side mold member for transferring a molding body, a movable side mold member and a pair of rotatable dowel members for transferring the toothed part, injecting and cooling a resin material in the cavity, separating the molding from the fixed side mold member by rotating the dowel members in association with opening of the movable side mold member, and then releasing the molding from the movable side member by rotating the dowel members, thereby molding the article. Thus, the double helical gear of the molding can be separated from the mold by rotating the dowels when released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the formation of a molded product such as a helical gear or the like having a tooth portion for screwing to a surface thereof.

In particular, the present invention relates to a forming method and a forming apparatus suitable for forming a bevel gear.

[0003] Further, the present invention, when a helical gear is used in the drive system, the vibration, noise, or abnormal wear of the gear generated during the transmission of the driving force due to the contact with the bottom of the tooth due to inappropriate backlash. The present invention relates to a wheel mechanism having a preventive means, a wheel mechanism, a molding method thereof, and a molding apparatus.

[0004] Further, the present invention relates to a gear mechanism of a helical gear that gives a degree of freedom to a thrust position of the gear when meshing a pair of helical gears.

[0005]

2. Description of the Related Art Japanese Patent No. 2879336 discloses a prior art relating to a method of manufacturing a bevel gear and a technology of a manufacturing apparatus.
There is an official gazette.

The patent publication discloses a method for manufacturing a helical gear, comprising two mold halves corresponding to the two halves of the gear, each of these mold halves being associated with one half of the gear. It has a corresponding mold cavity and an inner mating surface, which sealingly engages the inner mating surface of the other mold half, the two mating surfaces of both mold halves corresponding to the central plane of the gear. It is configured to be.

[0007] Further, the mold configuration of this publication is configured such that the gears rotate at the stage of drawing out the molded product.

[0008]

In the case of the helical gear, the teeth meshing with the mating gear have a relatively opposite twist angle, so that the thrust in the thrust direction at the time of transmitting the driving force of the gear train structure is reduced. It has the property of canceling out.

[0009] Like a bevel gear, the tooth portion is characterized in that the tooth portion twist angles are directed in directions opposite to each other from the center portion of the tooth portion, and are formed of a molding material such as a resin material. In the case of molding, it is difficult to match the phases of the teeth having the twist angles that are opposite to each other.

[0010] If the phases of the tooth portions of the torsion angles that are opposite to each other are shifted in manufacturing, the gear function as the helical gear cannot be realized.

The helical gear is employed in various driving machines, and its application to a fixing unit of an image forming apparatus can be considered from the transmission characteristic of the driving force.

Considering a fixing device incorporated in an image forming apparatus such as a copying machine, a laser beam printer, a facsimile machine, etc., FIGS. 1 and 2 show an example of a main configuration of the fixing device. Is a pressure roller, 102 is a planar heater, and 104 is a thin film formed in a cylindrical shape.

The pressure roller 100 has a silicone sponge (rubber) layer 100 around an aluminum core 100A.
B is formed into a roller shape, and its outer peripheral surface is a PPA tube 1
The structure is covered with 00C, and the surface is excellent in elasticity.

The planar heater 102 has a heater holder 106.
The heater holder 106 is fixed to the spring member 10.
8, the thin film 104 is disposed in parallel with the pressure roller 100 with the thin film 104 interposed therebetween and pressed against the pressure roller 100.

Heater holder 1 including planar heater 102
06 to the pressure roller 100, the pressure roller 10
0 of the silicone sponge layer 100B is elastically deformed,
A nip 110 having a certain width is formed between the pressure roller 100 and the thin film 104.

A driven gear 112 is attached to the metal core 100A of the pressure roller 100, and meshes with a driving gear 114 for transmitting a driving force.

The fixing device energizes and heats the planar heater 102 to pass a recording medium, such as paper, onto which a toner image has been transferred in the image forming section of the image forming apparatus, through the nip section 110, thereby generating heat and pressure. To fix the toner image on the recording medium.

In the fixing device having the above-described structure, the thin film 104 is rotationally driven by frictional force via the recording medium passing through the nip 110, and the rotation speed of the thin film 104 is equal to the speed of the recording medium passing through the nip. The speed is constant.

The pressure roller 100 slightly fluctuates in speed according to the meshing frequency of the driving gear and the driven gear.
The vibration propagates to the recording medium.

Further, the vibration generated in the fixing device propagates to the transfer device side of the image forming apparatus, which causes a transfer deviation of the meshing frequency of the driven gear.

When a helical gear or a helical gear is used, the meshing ratio of the gears can be increased, and the vibration generated in the fixing device can be reduced.

Further, in the case where the helical gear is used, no thrust force is generated by the transmission of the driving force, so that it is possible to prevent the thrust force from being applied to the pressure roller.

Further, in the case where the teeth having no gap (interval) are engaged with the joining surfaces of the two halves having different torsion directions of the teeth, such as a helical gear, the joining surfaces of the respective gears are engaged. If the positions of the two teeth in the thrust direction are not determined so as to exactly match each other, problems such as vibration, noise generation, and malfunction due to abnormal wear of the gears may occur.

The bevel gears 112, 1 according to one embodiment of the present invention
As shown in FIGS. 2, 3 and 4, reference numeral 14 is used to form engaging portions (200C, 300C) to be described later with a distance between the teeth between the bevel gears and the gears.

With this configuration, the above problem can be solved. In order to injection-mold such a bevel gear with a resin material, it is necessary to devise a cavity configuration for molding the engaging portion and a releasing operation after the bevel gear is molded in a molding die member. Becomes

The above-mentioned prior art patent registration number 2
In the case of the method of molding a herringbone gear described in US Pat. No. 879,336, the mold consists of two mold halves corresponding to the two halves of the gear, each of which is provided on one half of the gear. A respective bevel gear formed in two mold halves, having a corresponding mold cavity and an inner mating surface, said inner mating surface being in sealing engagement with the inner mating surface of the other mold half; It is intended to guarantee the accuracy of the phase of the tooth portions of the mutual gears.

However, in the case of the formation of the helical gear, the phase accuracy between the teeth of the helical gear is accurately formed only by the accuracy in assembling the mold member for forming the helical teeth. Must be guaranteed to a fairly high accuracy.

Further, in forming a bevel gear having a shape having an engagement portion and a shaft portion between the teeth of the bezel to which the present invention is to be applied, a method and a device for the forming device are devised. is necessary.

In the case of the molding method disclosed in the above-mentioned prior document, the helical gear of the molded article is configured to rotate the gear of the molded article at the time of releasing operation.
There is a possibility that the physical resistance between the mold member and the molded product is increased and the molded product is deformed.

In particular, there is an effect of the deformation action of the formed tooth shape.

Further, when the gear is released from the movable side of the mold half simultaneously with the opening of the mold member in the release operation, there is mechanical play (asobi) between the components of the mold mechanism. There is a time difference between the rotation operation of the gear and the ejector operation due to the opening of the mold, and the teeth of the molded product may be deformed.

One of the objects of the present invention is to provide an image forming apparatus which does not affect image accuracy such as transfer deviation caused by vibration of gears on a driving side and a driven side of a fixing device of the image forming apparatus.
Also, a gear for suppressing the generation of thrust force by drive transmission, and
It is to propose a gear mechanism and a method of manufacturing the gear.

An object of the present invention is to propose a forming method and a forming apparatus suitable for forming a helical gear provided with a backlash assurance function section (engaging section) at a central position of the tooth section as described above. is there.

Further, the present invention relates to a configuration of a bevel gear suitable for a constituent unit of an image forming apparatus, a molding method, and a molding apparatus for the reasons described above.

[0035]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a method for molding a molded article having teeth on its surface, comprising a fixed mold member for transferring a molded article main body and a movable mold. Forming a cavity for molding the molded article from a pair of rotatable piece members that transfer the mold member and the tooth portion, injecting a resin material into the cavity, and cooling, to form the movable-side mold member. With the opening, the rotation of the rotating piece member is separated from the fixed mold member, and subsequently, the mold release operation is performed from the movable mold member by rotating the rotating piece member. A molding method of a molded article having a tooth portion on a surface characterized by molding is proposed.

In the molding method of the invention proposed above, the helical gear of the molded product is held in a non-rotating state in the molding die member.

Further, as a gear used in a unit of the image forming apparatus, a bevel gear characterized in that an undercut portion is formed at the center of a tooth portion of the bevel gear is proposed.

Further, the present invention relates to a method of forming a bevel gear having an undercut portion formed at a central portion of a tooth portion, comprising a pair of rotary piece members for transferring the tooth portion disposed on a fixed and movable mold member. A slide member for forming the undercut portion is provided between the movable mold members, and when the movable mold member is opened, the rotary piece member is rotated in conjunction with the movement of the slide member to release the molded product. The above object is achieved by proposing a method of forming a bevel gear, which is characterized by being formed as described above.

The fixed mold member and the movable mold member are provided with cavities for forming helical gears, and a pair of rotary piece members for transferring the teeth of the helical gears are arranged on each of the mold members. A slide member forming an undercut portion at the center of the tooth portion of the bevel gear is disposed between the rotary piece members, and the mold is formed in conjunction with the movement of the slide member during a mold opening operation. The present invention proposes a method of forming a bevel gear, which is characterized in that a releasing operation is performed in a non-rotating state.

There is also an embodiment in which only one of the rotating piece members is rotated.

Further, a pair of rotating piece members separated at the center of the tooth portion for transferring the tooth portion of the helical gear and fixed-side and movable-side mold members for forming the gear body are provided. In the case of a mold operation, the manufacture of the above-mentioned helical gears is proposed by a proposal of a molding apparatus characterized by comprising means for rotating and driving the rotary piece member for holding and moving a molded product on a movable mold member during a mold operation. I do.

One aspect of the present invention is an apparatus for molding a molded article having a tooth portion on a surface, wherein a pair of rotating piece members are provided on a fixed mold member and a movable mold member, and the rotating piece member is provided with a pair of rotating piece members. A molding device for a molded product having teeth on the surface, characterized in that a slide member for forming an undercut portion on the surface of the molded product is disposed therebetween.

Further, the present invention proposes an embodiment of the forming apparatus, wherein the forming apparatus is a forming apparatus for forming a helical gear, and is provided with positioning means for determining a relative position of the pair of rotary pieces. .

Further, there is provided a molding apparatus according to the above aspect, further comprising a position releasing means for the positioning means of the molding apparatus.

The slide member is moved in conjunction with the opening operation of the movable mold member, and the molded product is held by the movable mold member in accordance with the movement of the slide member to perform the mold opening operation. There is an embodiment of a molding apparatus characterized by the following.

Further, in order to form and manufacture the helical gear from a resin material, the phases of the fixed-side and the movable-side mold members and the teeth of the helical gear at the center of the teeth are aligned. Although it is necessary, one of the present invention has a molding die member, and a rotating piece member which forms a cavity in which a tooth portion transfer portion for molding the bevel gear is formed together with the die member. Means for solving the above-mentioned problems are provided by a device for forming a bevel gear, characterized by comprising means for positioning the phase of the mutual gear portion of the bevel tooth at the center of the tooth of the bevel gear. Was planned.

Further, a pair of teeth forming rotary piece members for forming relative teeth of the bevel gear and a regulating member for regulating the relative position of the tooth forming rotary piece members are provided. The above-mentioned problem is solved by proposing an apparatus for forming a bevel gear.

In the above apparatus, the regulating member is a member for forming an undercut portion at the center of the tooth portion of the formed helical gear. suggest.

The present invention further provides a pair of helical gears on the driving side and the driven side, wherein an engaging portion is formed at the center of each of the helical gears. It contributes to improving the performance of the device.

Further, the present invention proposes an embodiment of the bevel gear, wherein the restricting portion is manufactured by molding a resin material having an undercut portion in the center of the tooth portion of each of the bevel gears.

Further, the present invention relates to a pair of helical gears, wherein each of the helical gears has an engaging portion other than the meshing portion of the tooth portions of the pair of helical gears. We propose a pair of bevel gears that are equipped with these.

One aspect of the present invention is to manufacture a gear for preventing vibration generated by a gear mechanism of a driving / driven mechanism used in the above-described image forming apparatus, and in particular, to manufacture a bevel gear capable of eliminating a thrust force by the driving mechanism. Proposed method and manufacturing equipment,
Contribute to image accuracy.

[0053]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment of the present invention will be described below with reference to FIGS.

FIGS. 3 and 4 are explanatory diagrams of a driven helical gear 200 and a driving helical gear 300 of the helical gear employed in the driving mechanism of the fixing device.

The driven helical gear 200 shown in FIG. 3 has teeth 200A, 200B and teeth 200A, 200B whose inclination angles of the teeth are opposite to each other from the center position.
Undercut-shaped engaging portion 20 formed at an intermediate position of
0C and a gear shaft 200D.

The driving helical gear 300 shown in FIG. 4 has teeth 300A, 300B and teeth 300A, 300B whose inclination angles of the teeth are opposite to each other from the center position.
Undercut-shaped engaging portion 30 formed at an intermediate position between
0C and a gear shaft 300D.

Each tooth portion is engaged with 200A and 300A,
The tooth portions 200B and 300B mesh with each other, and each engaging portion 200C
And 300C engage.

The engaged state is shown in FIGS.

The engaging portion 30 of the driving bevel gear 300
0C is an engaging portion 200C of the driven side bevel gear 200.
Is formed so as to be in contact with and engaged with.

FIGS. 5 to 9 show the driven bevel gear 20.
It is a figure explaining main part composition of a molding device when molding and manufacturing 0 with a resin material.

FIG. 5 is an explanatory view of the configuration of the main part of the molding apparatus according to the present invention. The fixed mold member 1 and the movable mold member 2 are shown.
Indicates a closed state.

FIG. 6 is a sectional view of a main part taken along the line AA of FIG.

FIG. 7 is an explanatory view of the state in which the mold is opened from the mold closed state in FIG. 5, and FIG. 8 is a sectional view taken along the line AA in the mold open state.

FIG. 9 is an explanatory diagram of the configuration of the control device of the present embodiment.

In the figure, reference numeral 4 denotes a fixed mold (piece).
A mold holding member of member 1, a runner bush holding member 6,
Reference numeral 8 denotes a fixed mold plate member, and reference numeral 10 denotes a runner.

Reference numeral 12 denotes a holding member for the movable mold (piece) member 2, 14 denotes a movable mold plate member, 16 denotes an ejector plate, and 18 denotes an ejector pin.

Reference numerals 20 and 22 denote rotating piece members which are features of the molding apparatus of the present invention.

The rotating piece members 20 and 22 are respectively disposed on the outer peripheral position side of the fixed mold member 1 and the movable mold member 2 and have a ring shape. Are provided with support members 24 and 26 for supporting the rotating pieces.

The rotating piece members 20 and 22 are fixed to the fixed mold member 1 and movable by rotating support members (bearings) 28 and 30 provided between the rotating piece members and the support members 24 and 26, respectively. Each is rotatably supported between the side mold members.

The rotating piece members 20 and 22 form a cavity space for forming a bevel gear of a molded product by the fixed mold member 1 and the movable mold member 2. Surfaces 20A and 22A facing the cavity space 22
Is formed to form a tooth shape of the helical gear when the molded product is a helical gear. Tooth portions 20A, 22A on the tooth portion transfer surface of the rotating piece members 20, 22
Are configured such that the inclination direction of each tooth portion forms the tooth portion (200A, 200B) of the aforementioned bevel gear 200.

The rotating piece member is made of SKD (die steel), and each mold member is made of SKH (high-speed steel).

Reference numerals 32 and 34 denote slide members for forming the undercut-shaped engaging portion 200C formed at the center of the teeth of the bevel gear of the molded product.
As shown in the figure, the upper and lower two plate members are configured to abut each other, and the tip of the plate member in the direction of the mold member (central portion) is formed into a half-shape so as to avoid the cylindrical portion of the bevel gear body of the molded product. Has formed.

The slide members 32, 34 are arranged so as to be sandwiched between the side surfaces 24A, 26A of the rotary piece support members 24, 26, and are interlocked with the opening operation of the mold by the angular pins 36, 38, so that the slide members 32, 34 It is configured to open and close.

In order to inject and solidify the helical gear into a mold with a molding material such as a resin material as in the present invention, the shape of the tooth portion of the helical gear is adjusted by the rotating pieces 20 and 22 having the above-described structure. Molded, and as described below, the undercut portion 2
A configuration is employed in which the mold opening operation is performed while the rotation of the molded product is restricted by the movement of the slide members 32 and 34 for molding 00C.

The teeth 200A and 200B of the helical gear are not simple in shape, the teeth are inclined (twisted), and the directions of the twists are opposite to each other with the center of the teeth as a boundary. In the case of forming the tooth portions 200A and 200B of the helical gear, it is necessary to devise a method for strictly defining the phase of the mutual tooth portion of the molded portion formed by the driving mold member.

Therefore, in the embodiment of the present apparatus,
Means are provided for determining the phase of each tooth of the formed bevel gear.

In this embodiment, the phasing of the tooth portions is determined by using the pin mounting holes 22B and 24B of the rotary pieces 20 and 22 as reference holes, and the positioning of the tooth forming portions 20A and 22A relative to each other. Is performed.

The positioning means will be described with reference to FIG.

FIG. 6 is a sectional view taken along the line AA in FIG. 5, and shows cylinder means 4 as means for determining the fixed position of the rotary piece member 20 arranged at the outer peripheral position of the movable mold member 2.
0 and 42 are provided, and positioning pins 40B and 42B are attached to the tip of the piston member of the cylinder. The positioning pins 40B and 42B are pins formed at the outer peripheral positions of the rotary piece members 22 and 24. Removable hole 22B,
24B is configured to be detachable in conjunction with cylinder operation.

A similar pin attaching / detaching hole is also provided on the fixed rotating piece member 22 so that the positioning pins 40B and 42B act simultaneously with the rotation positioning of the rotating piece member 20.
A rotating piece positioning means is arranged.

The positioning pin is provided with a sensor S-1 for detecting a pin operating position.
Check the proper position of the positioning pin by the signal of 1.
Accordingly, an operation of determining whether or not the phase adjustment of the rotating piece members 20 and 22 is appropriate is performed.

FIG. 9 shows a control device of the apparatus of the present embodiment. The driving means 44 for the movable mold member, the ejector pin operating means 46 for taking out the molded product, and the resin material injection control means 4 are shown.
8. Cylinder control means 50 of positioning pins 40, 42 for phase adjustment of the rotating piece members 20, 22;
It comprises a control means 52 for the positioning pin position confirmation sensor and a control means 54 for controlling the whole.

Next, the operation of the first embodiment will be described.

Each of the members is set to a molding ready state while the mold is closed as shown in FIGS.

The resin material used for manufacturing the helical gear of this embodiment is polyphenylene sulfide (PPS).

As a gear forming material for transmitting a driving force by screwing in a bevel gear or the like, a resin material such as polyacetal (POM) or nylon (PA) can be used in addition to the above-mentioned polyacetal.

In the mold closed state shown in FIGS. 5 and 6, the positioning pins 40B and 42B on the fixed side and the movable side are engaged with the positioning holes 22B and 24B of each rotating piece, and the confirmation operation is performed by a signal from the sensor control means 52. Is performed.

Thus, the fixed and movable rotary piece members 2
The phases of the 0,22 tooth portions match.

After the mold is closed as shown in FIGS. 5 and 6, a molten material of the resin material is injected from an injection cylinder (not shown) connected to the runner, and the molten resin material is injected into the fixed mold member, the movable mold, and the like. The mold member is filled in the cavity formed by each rotating piece member and the slide member.

After injecting a predetermined volume of the molten resin material, a constant pressure is maintained in the mold, and a cooling process of the resin material in the cavity is performed by injecting and circulating a cooling medium into a cooling pipe (not shown).

After the elapse of the solidification time of the injection resin to the predetermined hardness in the cooling step, the operation proceeds to the release operation of the molded product.

The releasing operation is performed by driving the movable mold member in the direction of arrow A in the figure by the movable mold driving means.

The opening operation of the movable-side mold member is executed by moving the movable-side mold plate member and the movable-side mold mounting member in the direction of the arrow A shown in the drawing by the mold driving means 44. The members 32, 34 move in the directions C, D away from the abutting position, as shown in FIGS. 7 and 8, corresponding to the inclination angles of the angular pins 36, 38.

At this time, the tip portions 32A, 34A of the half portions of the slide members 32, 34 are engaged with the bevel gear resin portion of the molded product as a molded portion of the undercut portion at the center of the bevel gear of the molded product. State, the slide member 3
The movement of the mold members 2 and 34 in the opening directions C and D generates a force in the direction of pressing against the movable mold member 2, and the restriction of the positioning pin is released, so that the movable mold member 2 of this molded product is released. The urging force on the fixed die member 1 induces the rotation of the rotating piece member 20 located at the outer peripheral position of the fixed mold member 1.

By this series of operations, the helical gear of the molded product moves non-rotatably with the movable mold member, and one tooth of the helical gear molded by the fixed mold member is rotated by the rotating piece member. The release operation is performed from the fixed-side mold member and the fixed-side rotating piece member by the operation.

In the state shown in FIGS. 7 and 8 at the position where the opening operation of the movable mold member is completed, the bevel gear of the molded product is completely separated from the fixed side.

In the separation completion position shown in FIGS. 7 and 8, the slide members 32 and 34 are located at positions completely deviated from the undercut position of the molded product, but are prevented from falling off by the movable-side rotating piece holding member. And regulates the end of the rotating piece member 22.

Subsequently, the ejector pin is pushed out by the operation of the ejector driving means 46, and the bevel gear of the molded product exerts a force in the direction of the arrow B shown in the figure by the ejecting action of the ejector pin. The movement of the article in the B direction is permitted by the rotation of the rotary piece member 22.

After the mold is opened by the above-described operation, the process is performed without the rotation of the helical gear of the molded product in the mold until the release of the molded product is completed.

In the structure of the apparatus shown in the first embodiment, the rotating piece members 20 and 22 are configured to rotate and drive both. However, one piece member may be configured to be in a non-rotating state. .

Description of Second Embodiment FIGS. 10 to 14 are explanatory diagrams of a second embodiment of the present invention.

FIGS. 10 and 11 are explanatory diagrams of the mold closing state of the molding apparatus, and FIGS. 12 and 13 are explanatory diagrams of the mold opening state.

FIG. 14 is a control block diagram of each means of the second embodiment.

In the figure, reference numeral 60 denotes a fixed mold (piece).
A member, 62 is a fixed side mold plate member, 64 is a sprue bush holding member, and 66 is a fixed side mold holding member.

Reference numeral 68 denotes a movable mold (piece) member, 70 denotes a movable mold plate member, 72 denotes a movable mold holding member, 74 denotes an ejector plate member, and 76 denotes an ejector pin.

Reference numerals 78 and 80 denote tooth members for forming a tooth portion of a bevel gear which are arranged at the outer peripheral positions of the fixed die member 60 and the movable die member 68, respectively. Portions 78A, 8 to be fitted to the outer peripheral surfaces of mold members 60, 68
0A, portions 78B and 80B forming a molding cavity for forming the teeth, and portions 78C fitted via holding members 82 and 84 and bearing members 86 and 88 for holding the rotating pieces. 80C or the like.

The pair of fixed and movable rotary members 78 and 80 together with the mold members 60 and 68 and a slide member 90 described later constitute a cavity for forming a bevel gear.

The rotating piece members 78 and 80 form a pair, and the teeth of the teeth forming cavity have a shape in which the inclination angles of the helical gears are different from each other. It is necessary to adjust the phase of the rotating piece member, and a phase adjusting means is provided.

The phase adjusting means includes slide members 90 and 14
0, a fixed stopper member 92 and the like.

The slide members 90 and 140 are in the form of a pair of plates, and the butting portion at the tip constitutes a cavity portion 90A for forming an undercut portion (engaging portion) at the center of the tooth portion of the formed bevel gear. are doing.

The slide member 140 is shown in FIG.
The upper portion is formed with an engaging portion 140A for engaging with a driving means 96 for driving the undercut member to open and close.

The fixed stopper member 92 has a ring shape, and a part of the ring portion is cut out to form a cut-out portion 92A.

The fixed stopper 92 is fixed to the holding members 82 and 84 with the slide members 90 and 140 interposed therebetween.

In the closed state of the mold shown in FIG. 10, the two slide members 90 and 140 are in the closed position.

The rotating piece members 78 and 80 have abutment surfaces 90C of the slide members 90 and 140 on their outer peripheral sides.
Protrusions 78C and 80C that engage with the slide members 90 (not shown) are provided. When the slide member 90 moves in the closing direction, the protrusions 78C and 80C are pressed to rotate the rotating piece members 78 and 80. Manipulate.

Each rotating piece member is rotated in conjunction with the lowering operation of the slide member to the closed position, and the phase adjustment of the cavity for forming the teeth of each rotating piece member is automatically performed at the closing position of the mold. Done in

Next, the operation of the second embodiment will be described.

As shown in FIGS. 10 and 11, when each of the mold members is in the closed position, the slide member is positioned at the closed position by the driving means 96, whereby the rotating piece members 78 and 80 are moved to the positions shown in FIGS. As shown in FIG. 7, the rotation operation of the slide member to the phase adjustment position by the butting surface 90C is performed.

The cavity space for forming the bevel gear includes a fixed mold member 60, a movable mold member 68, a pair of rotating pieces 78 and 80, and a pair of slide members 90 and 14.
0.

Injection of the molten resin material from an injection cylinder (not shown) is performed by the injection control means 132 by the control operation of the control means 130, and the resin material is filled into the cavity. A cooling step is performed by maintaining a constant pressure on the material and supplying a cooling medium to a cooling pipe (not shown).

After the cooling step, a mold release operation of the molded product is performed.

The movable side moves in the direction of arrow C in the figure by opening the movable side mold member.

At the same time, the slide driving means 96 moves the slide members 90 and 140 in the direction of arrow D.

By the mold opening operation in the direction C on the movable side and the operation of moving the slide member in the direction D, the butted surface 90C of the undercut molding portion of the slide member 90 presses the molded article against the movable side. With the action and the action of regulating the rotation of the molded article, the engagement between the projections 78C, 80C of the rotating piece members 78, 80 and the abutting surfaces of the slide members is released. It rotates in response to movement with the side mold member.

At the mold opening end position, the molded product is completely separated from the fixed mold.

Thereafter, the release operation of the molded product from the movable mold member by the ejector pin of the ejector control means 134 is performed, and the release operation of the molded product is completed.

After the mold release operation is completed, after the work of cleaning the inside of the mold cavity, the operation of closing the movable mold and the operation of returning the slide member to the molding start position by the driving means are performed.

In conjunction with the operation of returning the slide member to the molding start position, the phase adjustment of the tooth cavities of the rotary pieces 78 and 80 is automatically performed.

In the above embodiment, the case of forming the driven side gear 200 shown in FIG. 3 has been described. However, the driving gear 300 shown in FIG. What is necessary is just to change into the shape of the said engaging part 300C of the driving helical gear 300.

That is, in the case of the first embodiment, the cavity surface at the distal end of the slide member 32 may be formed in a shape corresponding to the engaging portion of the gear 300.

[0131]

According to the present invention, there is provided a method for molding a molded article having teeth on its surface, comprising a fixed mold member for transferring a molded article main body, a movable mold member and a pair of molds for transferring the teeth. Forming a cavity for molding the molded article from the rotatable piece member, injecting a resin material into the cavity, and performing a cooling step. With the opening of the movable mold member, the rotation of the rotary piece member By operation, the molded product is separated from the fixed mold member, and subsequently, the mold is formed by performing a releasing operation by rotating the rotary piece member from the movable mold member. By the method of molding a molded article having a tooth portion on the surface, the bevel gear of the molded article can be separated and taken out of the mold without rotating during the releasing operation.

Further, according to the present invention, a bevel gear characterized in that an undercut portion was formed at the center of the tooth portion of the bevel gear was obtained.

Further, when the bevel gear of the present invention having the above structure is used for a driving force transmission mechanism, it is possible to give a degree of freedom of a thrust position for meshing a pair of bevel gears.

One aspect of the present invention is to provide a method for forming a bevel gear in which an undercut portion is formed at the center of a tooth portion.
A slide member (undercut molding member) for molding the undercut portion is provided between a pair of rotary piece members for transferring the tooth portions disposed on the fixed and movable mold members, and a movable member for the movable mold member is provided. Forming a bevel gear, wherein the rotating member is rotated in conjunction with the movement of the slide member (the undercut forming member) during the opening operation to release the molded product; Managed to get the way.

Further, according to the present invention, the fixed mold member and the movable mold member are provided with cavities for forming helical gears, and a pair of rotating piece members for transferring the tooth portions of the helical gears are provided in each of the molds. A slide member forming an undercut portion at the center of the tooth portion of the bevel gear is disposed between the rotating piece members, and is formed in conjunction with the movement of the slide member during a mold opening operation. The method of forming a bevel gear is characterized in that the bevel gear is operated to be released in a non-rotating state, thereby increasing the forming accuracy of the engaging portion of the undercut portion at the center of the tooth portion of the bevel gear. I was able to do things.

FIG. 15 shows an apparatus configuration in which a pair of helical gears manufactured by the method and apparatus for manufacturing a helical gear according to the present invention are used as a driving mechanism of a fixing device of an image forming apparatus.

By employing the helical gear mechanism according to the present invention, the gear meshing ratio can be increased without generating thrust force, vibration caused by gear meshing can be suppressed, and image misalignment can be eliminated. I was able to.

That is, when the helical gear manufactured according to the present invention is in a meshing engagement state between the helical gear on the driving side and the helical gear on the driven side, as shown in FIGS. By maintaining the engaged state between the undercut forming part 200c and the undercut forming part 300C of the driving gear, the backlash is appropriately maintained,
Vibration generated between the gears can be suppressed.

Further, in the assembled state of the driven side helical gear 200 and the driving side helical gear 300 as a driving mechanism, the undercut portion 3 of the driving side gear 300 under the dimensional permissible conditions for the assembly of the gear 200 and the gear 300.
00D and the undercut portion 200 of the driven gear 200
It is sufficient that the alignment of C coincides with the center position state as shown in FIG. 17, but as shown in FIG. 16 or FIG.
There may be a case where the alignment position is shifted left and right.

Even in such a case, in the case of a helical gear having an engaging portion between each inclined tooth portion according to the present invention, the dimension of the engaging portion can be adjusted within an allowable range. Thus, vibration and noise during gear engagement could be suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a fixing device of an image forming apparatus.

FIG. 2 is a side view in the P direction of FIG. 1;

FIG. 3 is an explanatory view of a configuration of a bevel gear formed by the present invention.

FIG. 4 is an explanatory diagram of a configuration of a bevel gear formed by the present invention.

FIG. 5 is an explanatory view of a state in which a molding apparatus mold is closed.

FIG. 6 is an explanatory view of a cross section taken along line AA of FIG. 1;

FIG. 7 is an explanatory view of a state in which a mold of the molding apparatus is opened.

FIG. 8 is an explanatory view of a cross section in the AA direction of FIG. 1;

FIG. 9 is a control block diagram of the first embodiment.

FIG. 10 is an explanatory view of a state in which a mold of the molding apparatus is closed.

FIG. 11 is an explanatory view of a cross section taken along line BB of FIG. 10;

FIG. 12 is an explanatory view of a state where a mold of the molding apparatus is opened.

FIG. 13 is an explanatory view of a section taken along line BB of FIG. 11;

FIG. 14 is a control block diagram of the second embodiment.

FIG. 15 is a configuration diagram of a fixing device incorporating the helical gear mechanism according to the present invention.

FIG. 16 is an explanatory diagram of the operation / effect of the helical gear of the present invention.

FIG. 17 is an explanatory diagram of the operation / effect of the helical gear of the present invention.

FIG. 18 is an explanatory diagram of the operation / effect of the helical gear of the present invention.

[Explanation of symbols]

 1, 60 Fixed mold (piece) member 2, 62 Movable mold (piece) member 4, 66 Fixed mold holding member 6 Runner bush 8 Fixed mold plate member 12 Holding member 14 Movable mold plate member 16 Ejector Plate 18 Ejector pin 20, 22, 78, 80 Rotating piece member 24, 26, 82, 84 Supporting member 28, 30, 86, 88 Bearing 20A, 22A Tooth cavity 32, 34, 90, 90 of rotating piece Slide member 36, 38 Angular pin 40, 42 Cylinder means 40B, 42B Positioning pin 44 Die driving means 46 Ejector operating means 48 Injection controlling means 50 Cylinder controlling means 92 Fixed stopper 200 Driven side helical gear 300 Drive side helical gear

Continued on the front page (72) Inventor Jun Nakagaki 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 3J030 AB01 AC03 AC10 BA06 BC08 4F202 AA23 AA29 AH12 AR07 CA11 CB01 CK32 CK43 CK55 CM01

Claims (20)

[Claims] 1. A method for molding a molded article having a tooth portion on a surface, comprising: a fixed mold member for transferring a molded article main body, a movable mold member, and a pair of rotatable mold members for transferring the tooth portion. A cavity for molding a molded article having the tooth portion is formed from the bridge member, a resin material is injected into the cavity, and a cooling step is performed. By operation, the molded product is separated from the fixed mold member, and subsequently, the mold is formed by performing a releasing operation by rotating the rotary piece member from the movable mold member. A method for molding a molded article having a tooth portion on a surface. 2. The apparatus according to claim 1, wherein the pair of bridge members hold one of the bridge members in a non-rotating state.
A molding method of the molded article according to the above. 3. A molding method of a gear having a tooth portion on a surface, comprising: forming a fixed mold piece member, a movable mold piece member, and a tooth portion of a movable gear for molding a gear body of a molded product. A rotatable rotating piece member to be molded, and a fixed piece member that forms the teeth of the fixed-side gear fixed to the fixed-side mold piece member, form the cavities of the gears. Injection of the resin material, through a cooling step, with the opening of the movable-side mold piece member, perform separation of the molded product gear from the fixed-side mold piece member by rotating the rotary piece member, A method of forming a gear, characterized in that molding is performed by performing a releasing operation of a molded product gear from a movable-side mold piece member by rotating the rotating piece member. 4. The method according to claim 3, wherein the gear is a helical gear. 5. A bevel gear characterized in that an undercut portion is formed in the center of a tooth portion of the bevel gear. 6. A helical gear having a pair of helical gears on a driving side and a driven side, wherein an engaging portion is formed at a central portion of each of the helical gears. 7. The hatch according to claim 4, wherein the engaging portion is manufactured by molding a resin material having an undercut portion in a central portion of a tooth portion of each of the hatch gears. gear. 8. A pair of helical gears, wherein the helical gears further include an engaging portion other than the meshing portion of the teeth of the pair of helical gears, wherein the engaging portions engage with each other. A pair of mountain gears. 9. The bevel gear is formed by a molding process using a resin material, and the engaging portion is formed between teeth of each of the bevel gears by undercut molding. The bevel gear according to claim 8, wherein 10. A pair of helical gears composed of a driven side and a driving side, wherein a toothed portion of the helical gear is provided between teeth.
A bevel gear characterized in that an intermediate portion is provided for enabling the respective bevel gears to move in the axial direction of the bevel gear. 11. A method of forming a bevel gear having an undercut portion formed at a central portion of a tooth portion, wherein the method comprises a pair of rotary piece members for transferring the tooth portion disposed on a fixed and a movable mold member. A slide member for forming the undercut portion is provided, and when the movable mold member is opened, the rotary piece member is rotated in conjunction with the movement of the slide member to release the molded product. A method of forming a bevel gear, characterized in that it is formed by molding. 12. A fixed mold member and a movable mold member are provided with cavities for forming helical gears, and a pair of rotary piece members for transferring tooth portions of the helical gears are arranged on each of the mold members. A slide member forming an undercut portion at the center of the tooth portion of the bevel gear is disposed between the rotary piece members, and the mold is formed in conjunction with the movement of the slide member during a mold opening operation. A method of forming a bevel gear, comprising releasing a gear in a non-rotating state. 13. A pair of rotating piece members separated at the center of the tooth portion for transferring the tooth portion of the helical gear, and fixed-side and movable-side mold members for forming the gear body. A molding apparatus, comprising: means for rotating and driving said rotating piece member for holding and moving a molded product on a movable mold member during a mold operation. 14. An apparatus for molding a molded article having a tooth portion on a surface, wherein a pair of rotating piece members are provided on a fixed mold member and a movable mold member, and the molded article is provided between the rotating piece members. A molding device for a molded article having a tooth portion on a surface, wherein a slide member forming an undercut portion is disposed on the surface. 15. The molding apparatus according to claim 14, wherein said molding apparatus is a molding apparatus for molding a helical gear, and further comprising positioning means for determining a relative position between said pair of rotary piece members. . 16. The molding apparatus according to claim 14, further comprising a position releasing means for said positioning means of said molding apparatus. 17. A moving operation of the slide member in conjunction with an opening operation of the movable mold member, and holding the molded product on the movable mold member in accordance with the movement of the slide member to perform a mold opening operation. The molding apparatus according to claim 14, wherein the molding is performed. 18. An apparatus for molding a bevel gear from a resin material, comprising a molding member and a cavity formed with a tooth part transfer portion for molding the bevel gear together with the mold member. And a means for positioning the phase of the mutual gear portion of the toothed teeth at the center of the teeth of the toothed gears. . 19. A rotary member having a pair of teeth forming rotary members for forming relative teeth of a bevel gear, and a restricting member for restricting a relative position of the teeth forming rotary member. A device for forming a bevel gear. 20. The apparatus according to claim 18, wherein the restricting member is a member that forms an undercut portion at a central portion of a tooth portion of the formed helical gear.