JPH10249877A - Molding apparatus of long axis member and its molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding apparatus and method for a long axis member having a light weight and small bending deformation of a low cost by providing a satisfactory show in an external appearance. SOLUTION: The molding apparatus for a long axis member comprises a mold having at least a body cavity 28 for forming a body 22, first and second axis cavities, a resin casting unit 32 for casting hollow forming medium for forming a hollow part along a central axis via a first axis cavity 29, a mold resin casting unit 31 provided at a cavity side from the unit 32, and an excess resin receiving cavity 34 receiving excess resin in the cavity by casting the hollow forming medium of the molten resin charged in the cavity, a medium casting unit for casting predetermined pressure hollow forming medium from the unit 32, and a resin charging unit 40 for charging the molten resin in the cavity from the unit 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin material having a hollow portion substantially concentric with a central axis and extending long in the direction in which the central axis extends. The present invention relates to a molding device and a molding method for a long-axis member in which through holes are formed at both ends in the direction to communicate the hollow portion to the outside, and the through holes are substantially concentric with the central axis. More specifically, a small-diameter shaft portion is formed at both ends of a main body portion having a hollow portion extending substantially in the direction in which the central axis extends substantially concentrically with the center axis, and the hollow portion communicates with the outside through the shaft portion. The present invention relates to a molding device and a molding method of a long-axis member in which a hole is formed and whose through hole is substantially concentric with a central axis.

[0002]

2. Description of the Related Art When a long shaft member is cut from a synthetic resin round bar, the cost of a synthetic resin material used for manufacturing the long shaft member increases and the weight of the long shaft member increases. Further, in the long shaft member used for transporting the toner and the like, a plurality of spiral protrusions constituting a screw for transporting the toner and the like are provided at intervals on the outer periphery of the main body, and both ends of the main body in the axial direction are provided. Since the shaft portion must be provided in the, the shape of the article is complicated. When such a long shaft member is cut from a synthetic resin round bar, the shape of the article is complicated, so that the number of processing steps is increased and the product cost is increased accordingly.

Therefore, there is known a technique of integrally molding the entire long shaft member (see Japanese Patent Application Laid-Open No. 5-208460). In this technology (gas injection method),
As shown in FIG. 32, the molded product cavity 1 of the molding die
A gate 2 for supplying a synthetic resin material in a molten state is provided substantially on the extension of the central axis O0 of the above, and a gas supply pipe (gas supply nozzle) 3 is connected to the gate 2 from a direction substantially perpendicular to the gate 2. .

In this technique, a predetermined amount of a synthetic resin in a molten state to be injected into a molded product cavity 1 is measured, and a gate 2
After the synthetic resin material 4 in the molten state is supplied from, pressurized gas is injected from the gas supply pipe 3 into the synthetic resin material 4 in the molten state. Then, the synthetic resin material 4 in the molten state is pressed and spread over the entire inner surface of the molding die by the pressure of the pressurized gas. As a result, a hollow long-axis member having the same outer surface shape as the inner surface shape of the molding die is formed.

[0005] That is, as shown in FIG.
1 having a hollow portion 5 elongated in a direction in which the body portion 1 extends.
And a long shaft member 8 having a shaft portion 7 smaller in diameter than the main body portion 6 at both ends of the main body portion 6.

[0006]

However, in the long shaft member 8 formed by this kind of technique, the pressurized gas supplied from the gas supply pipe 3 bends at a substantially right angle and flows into the molded product cavity 1. Therefore, bending deformation due to uneven thickness is likely to occur in the long shaft member 8 as a molded product. In addition, a through hole 9 for communicating the hollow portion 5 to the outside is generated on the outer peripheral surface of one of the pair of shaft portions 7 based on the supply of the pressurized gas, which is not preferable in appearance.

A metal shaft may be used for the shaft portion 7 of the long shaft member 8 in order to receive rotational power. Long shaft member 8 provided with metal shaft 7 at one end
In the case of molding, for example, as shown in FIG. 34, a metal shaft 7 is inserted into the molded product cavity 1 on the side far from the gate 2 and the synthetic resin material 4 in a molten state is removed from the gate 2 shown in FIG. After the injection, a pressurized gas is supplied from the gas supply pipe 3. However, the amount of the molten resin actually measured in each molding cycle varies.

[0008] The hollow ratio fluctuates based on the variation in the measurement. That is, the molten resin is injected into this molding die by measuring 70% of the cavity volume so as to have a hollow ratio of about 30% of the volume of the molded product. Therefore, when the amount of the molten resin is large, the gate 2 of the molded product cavity 1
A pool portion 10 of the synthetic resin material 4 in a molten state is formed near the metal shaft 7 far from the metal shaft 7, and the synthetic resin material in the molten state in the pool portion 10 is hard to be solidified, the molding cycle time is prolonged, and the product cost is reduced. Higher problems occur. Further, when the synthetic resin material in the molten state of the pool portion 10 is solidified, the molded product is deformed due to a large amount of shrinkage of the pool portion 10, and the dimensional accuracy is deteriorated. In addition, when the synthetic resin material in the molten state of the pool portion 10 is cured, the portion of the completed long shaft member 8 becomes a thick portion, which is not preferable.

On the other hand, when the amount of the molten resin is small,
The thickness near the metal shaft 7 far from the gate 2 is reduced.

A metal shaft 7 is provided at both ends of the long shaft member 8.
When insert molding is used, as shown in FIG.
The gate 2 and the gas supply pipe 3 must be provided in a direction orthogonal to the central axis O0. Also in this case, the pressurized gas supplied from the gas supply pipe 3 bends at a substantially right angle and flows into the molded product cavity 1, so that the molded product is deformed due to uneven wall thickness. In addition, since the pool portion 10 is generated in the vicinity of the metal shaft 7 far from the gate 2,
There is a similar problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an apparatus and a method for forming a long shaft member which has good appearance, is inexpensive, is light in weight, and has little bending deformation. Is to do.

[0012]

According to a first aspect of the present invention, in order to solve the above-mentioned problems, a main body made of a synthetic resin material is substantially concentric with a center axis and extends in a direction in which the center axis extends. A hollow portion is provided inside, and a first shaft portion and a second shaft portion each having a diameter smaller than that of the main body portion are formed at both ends of the main body portion. Each hollow portion communicates the hollow portion to the outside. An apparatus for forming a long-axis member in which a through-hole is formed and the through-hole is substantially concentric with the central axis, wherein the main body is molded with a cavity central axis corresponding to the central axis of the main body. A main body cavity, first and second shaft cavities for molding the first and second shafts, and a hollow forming medium for forming the hollow along the central axis on the first shaft. A medium injection section to be injected through an internal cavity, and a cavity more than the medium injection section. A resin injecting portion for injecting molten resin provided on the side of the cavity, and an excess resin in the cavity formed by the injection of the hollow forming medium among the molten resin filled in the cavity; A molding die having at least an excess resin receiving cavity received through, a medium injection device for injecting the hollow forming medium at a predetermined pressure from the medium injection unit,
A resin filling device for filling the cavity with the molten resin at a predetermined pressure from the resin injection unit.

According to a second aspect of the present invention, there is provided an apparatus for forming a long shaft member,
The resin filling device is controlled by a control device that injects a predetermined amount of the molten resin into the cavity by a predetermined pressure, and then controls the stopping pressure to such a degree that the molten resin stops at the resin injection unit. After the injection of the predetermined amount of molten resin into the cavity by the resin filling device is completed, the medium injection pressure is controlled by a medium control device that injects the hollow forming medium, and the medium injection pressure is equal to or higher than the stop pressure. I have.

According to a third aspect of the present invention, there is provided an apparatus for forming a long shaft member,
After the injection of the predetermined amount of the molten resin from the resin filling device into the cavity is completed, the hollow forming medium is injected into the molten resin, and the inner surface of the molten resin formed as a hollow by the hollow forming medium is stabilized. And a medium injection control device for operating the medium injection device.

According to a fourth aspect of the present invention, there is provided an apparatus for forming a long shaft member,
The stability of the inner surface of the molten resin is such that the temperature of the inner surface of the molten resin existing at a location communicating with the molten resin present in the first shaft portion cavity and the molten resin present in the main body cavity is equal to or lower than the softening point. Is determined by the temperature.

According to a fifth aspect of the present invention, there is provided an apparatus for forming a long shaft member,
After the hollow forming medium is injected from the first shaft cavity to the second shaft cavity through the main body cavity by the medium injection device, the removing device removes the hollow forming medium from the hollow portion.

According to a sixth aspect of the present invention, there is provided an apparatus for forming a long shaft member,
The total amount of the molten resin injected by the resin injection device and the injection amount of the hollow forming medium injected by the medium injection device is the volume of the main body cavity formed in the molding die and the volume It is not less than the sum of the volumes of the first and second shaft cavities.

According to a seventh aspect of the present invention, there is provided an apparatus for molding a long shaft member,
The hollow forming medium is a gas or a liquid.

[0019] The apparatus for forming a long shaft member according to claim 8 is
An insert member having a through hole concentric with the center of the shaft portion is installed in the first shaft portion cavity or the second shaft portion cavity.

According to a tenth aspect of the present invention, in the molding apparatus for a long shaft member, an insert member having a through hole concentric with the center of the shaft portion is provided in the first shaft portion cavity and the second shaft portion cavity. Features.

It is preferable that the through holes according to the eighth and tenth aspects have a conical shape whose diameter gradually increases toward the main body cavity.

13. The apparatus for molding a long shaft member according to claim 12, wherein a temperature adjusting member is disposed near the medium injection portion, and the temperature adjusting member is a molten resin of the medium injection portion filled from the resin filling device. Is controlled by a temperature controller so as to maintain a molten state.

14. The apparatus for molding a long shaft member according to claim 13, wherein the temperature control device is configured such that at least the hollow forming medium passes through a molten resin filled in the first shaft portion cavity and the main body cavity is formed. It operates until it is injected into the molten resin filled therein.

According to a fourteenth aspect of the present invention, the main body made of a synthetic resin material has therein a hollow portion which is substantially concentric with the central axis and extends in the direction in which the central axis extends. A first shaft portion and a second shaft portion having a smaller diameter than the main body portion are formed in the portion, and a through hole is formed in each of the shaft portions so as to communicate the hollow portion to the outside, and the through hole is connected to the central shaft. A molding device for a substantially concentric long axis member, wherein a main body cavity having a cavity center axis corresponding to the central axis of the main body to form the main body, and the first and second shafts are formed. First and second shaft cavities, a medium injection unit for injecting a hollow forming medium for forming the hollow along the central axis through the first shaft cavity, and a medium injection unit. The resin injection part for the molten resin injection provided on the cavity side A molding die having at least an extra resin receiving cavity for receiving, through the second shaft portion cavity, extra resin that becomes excess in the cavity by injecting the hollow forming medium among the molten resin filled in the cavity. A medium injection means for injecting the hollow forming medium at a predetermined pressure from the medium injection section, and a resin filling means for filling the molten resin into the cavity at a predetermined pressure from the resin injection section. Have.

According to a fifteenth aspect of the present invention, the main body made of a synthetic resin material has therein a hollow portion which is substantially concentric with the central axis and extends in the direction in which the central axis extends. A first shaft portion and a second shaft portion having a smaller diameter than the main body portion are formed in the portion, and a through hole is formed in each of the shaft portions so as to communicate the hollow portion to the outside, and the through hole is connected to the central shaft. An apparatus for forming a substantially concentric long-axis member, comprising: a body cavity having a cavity center axis corresponding to the center axis of the body to mold the body, and formed at both ends of the body. First and second shank cavities for molding the first and second shank portions, and a hollow forming medium for forming the hollow portion along the central axis are injected through the first shank cavities. A medium injection section, provided on the cavity side with respect to the medium injection section; A resin injection portion for injecting the molten resin, and receiving through the second shaft portion cavity, in order to receive, of the molten resin filled in the cavity, excess resin that becomes excess in the cavity due to the injection of the hollow forming medium. A molding die having an excess resin receiving cavity, and a medium outlet for allowing the hollow forming medium to flow out from the opposite side of the excess resin receiving cavity from the side communicating with the second shaft portion cavity; A medium injection device for injecting the hollow forming medium at a predetermined pressure from a medium injection portion, and a resin filling device for filling the molten resin into the cavity at a predetermined pressure from the resin injection portion. ing.

In the apparatus for molding a long shaft member according to claim 16, the medium outflow portion is opened by opening / closing means when the molten resin filled in the excess resin receiving cavity is in a desired hardened state, and the medium outflow portion is opened. The hollow forming medium flows out through the section.

In a preferred embodiment of the present invention, the resin filling device injects a predetermined amount of the molten resin into the cavity by a predetermined pressure, and then stops the molten resin at the resin injection portion. The medium injection device is controlled by a control device having a stationary pressure of about a predetermined level. The pressure is controlled, and the medium injection pressure is equal to or higher than the stop pressure and the molten resin filled in the excess resin receiving cavity is in a desired hardened state. The molding device for a long shaft member according to claim 15, wherein the pressure is set so that the pressure can flow out.

In the molding device for a long shaft member according to the present invention, the resin filling device injects a predetermined amount of the molten resin into the cavity by a predetermined pressure, and then the molten resin stops at the resin injection portion. The medium injection device is controlled by a control device having a stationary pressure of about a predetermined level. The pressure is controlled, and the medium injection pressure is equal to or higher than the stop pressure and is set to a pressure at which the hollow forming medium can flow out to the outflow portion through the molten resin filled in the excess resin receiving cavity.

According to a preferred embodiment of the present invention, the main body made of a synthetic resin material has therein a hollow portion which is substantially concentric with the central axis and extends in the direction in which the central axis extends. First and second shaft portions having a smaller diameter than the main body portion are formed in the portion, and a through hole is formed in each of the shaft portions to communicate the hollow portion to the outside, and the through hole is substantially concentric with the central axis. A method of molding a long-axis member, wherein a resin injection is formed at one end of a main body cavity having a center axis of a cavity corresponding to the center axis of the long-axis member and molding the long-axis member. A resin injecting step of injecting a synthetic resin material in a molten state into a portion from a direction intersecting the central axis; While pressing against the inner wall of the cavity and forming a hollow part The main body cavity is moved from one end to the other end, and the excess molten synthetic resin material is guided from the other end of the main body cavity to the extra resin receiving cavity, and A hollow forming medium injecting step of maintaining a predetermined pressure, and cooling and hardening at least the inner surface and the outer surface of the synthetic resin material in the molten state, and thereafter, a take-out step of taking out a molded product from the cavity, I do.

A method of forming a long shaft member according to a nineteenth aspect is characterized in that a removing step of removing the hollow forming medium in the hollow portion is provided between the hollow forming medium injecting step and the removing step. I do.

According to a twentieth aspect of the present invention, in the method for forming a long shaft member, the hollow forming medium in the hollow portion is taken into consideration in consideration of the dimensional accuracy of the long shaft member and the degree of progress of the curing of the molten synthetic resin material. A time for keeping the pressure constant is set.

According to a twenty-second aspect of the present invention, in the method for molding a long shaft member, the hollow forming medium is injected immediately before or immediately after the injection of the molten synthetic resin material is stopped.

According to a twenty-second aspect of the present invention, a main body made of a synthetic resin material has therein a hollow portion which is substantially concentric with a central axis and extends in the direction in which the central axis extends, and both ends of the main body. First and second shaft portions having a smaller diameter than the main body portion are formed in the portion, and a through hole is formed in each of the shaft portions to communicate the hollow portion to the outside, and the through hole is substantially concentric with the central axis. A molding method for molding a main body portion and first and second shaft portions of the long shaft member having a cavity center axis corresponding to the center axis of the long shaft member. The synthetic resin material in a molten state is injected into a resin injection portion provided on the first shaft portion cavity side of the cavity from a direction intersecting with the central axis, and a gas is injected by a gas nozzle from a direction parallel to the central axis. A molten synthetic resin material is pressed against the inner wall of the molding cavity. It is moved toward the second shaft portion cavity while attaching and forming the hollow portion, and the excess molten resin due to the formation of the hollow portion is guided to the excess resin receiving cavity through the second shaft portion cavity, and the inside of the hollow portion is formed. By holding the gas at a predetermined pressure and cooling and curing the molten resin, thereafter, degassing the inside of the hollow portion, taking out a molded product from the molded product cavity, and cutting unnecessary portions of the molded product, It is characterized in that the long shaft member is formed.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an apparatus and a method for forming a long shaft member according to the present invention will be described.

[0035]

Embodiment 1 In FIG. 1, reference numeral 20 denotes a long shaft member. The long shaft member 20 has a cylindrical main body 21 formed of a synthetic resin material. The main body portion 21 is substantially concentric with the central axis O1 and extends in the direction in which the central axis O1 extends.
2 inside. At both ends of the main body 21, the main body 21
First and second cylindrical portions 23 having a smaller diameter than the cylindrical shape are formed. Each shaft portion 23 is formed with a through hole 24 that communicates the hollow portion 22 to the outside. This through-hole 24 has a central axis O1.
And almost concentric. On the outer periphery of the main body 21, a plurality of spiral projections 25 forming a transfer screw are formed at intervals. The through-hole 24 is formed by injecting a synthetic resin material in a molten state into a molding die described later, and then injecting a gas as a hollow forming medium by a gas injection method from a direction parallel to the central axis O1. As the hollow forming medium, a liquid can be used in addition to a gas (gas).

FIG. 2 shows a mold for molding the long shaft member 20 shown in FIG. 1. In FIG. 2, reference numeral 26 denotes a fixed mold, and 27 denotes a movable mold. A body cavity (molded product cavity) 28 corresponding to the body 21 is formed between the fixed mold 26 and the movable mold 27. This body part cavity 28
Has a cavity center axis O2 corresponding to the center axis O1 of the main body 21. First and second shaft portion cavities (molded product cavities) 29, 3 corresponding to the first and second shaft portions made of a synthetic resin material are provided at both ends of the main body cavity 28, respectively.
0 is formed. At one end of the main body cavity 28, a gas nozzle (medium injection part) 32 for injecting gas from a gas pressure source into the main body cavity 28 is provided substantially concentrically with the central axis O2. Also, the main body cavity 28
A resin injection portion 31 for injecting a synthetic resin material in a molten state is formed between the gas nozzle 32 and the cavity 29. An injection passage 3 for injecting a synthetic resin material in a molten state into the fixed mold 26 from a direction (a direction orthogonal to) the direction in which the gas is injected from the gas nozzle 32 into the resin injection section 31.
3 are formed. An excess resin receiving cavity 34 for receiving an excess of the molten synthetic resin material injected from the resin injection unit 31 is provided at the other end of the main body cavity 28.
Are formed. The excess resin receiving cavity 34 communicates with the main body cavity 28 with the connection passage 35 and the second shaft cavity 30 interposed therebetween. The extra resin receiving cavity 34 is substantially concentric with the central axis O1. A concave portion 36 for forming the projection 25 is formed on the inner peripheral wall of the main body cavity 28.

In this molding die, a synthetic resin material in a molten state is injected into the resin injection portion 31 through the injection passage 33, and gas is supplied to the main body cavity 28 from the direction of the central axis O2. The synthetic resin material 4 in the molten state is moved toward the extra resin receiving cavity 34 while being pressed against the entire inner surface of the main body cavity 28 by the pressure of the pressurized gas. The excess molten synthetic resin material that is not used as the long shaft member 20 is pushed out from the central axis direction toward the excess resin receiving cavity 34 by the pressure of the gas. The material 4 is distributed almost uniformly. As a result, FIG.
As shown in Fig. 7, a hollow molded product 20 'having the same outer shape as the inner shape of the molding die is formed.

This molded product 20 ′ has a thick portion 31 ′ corresponding to the resin injection portion 31, a thick portion 35 ′ corresponding to the connection portion 35, and a surplus portion 34 ′ corresponding to the extra resin receiving cavity 34. The long shaft member 20 is completed by cutting the molded product 20 ′ at the points indicated by arrows A and A.

For details of the method of forming the long shaft member 20, see the forming method of the embodiment described later.

[0040]

Embodiment 2 FIGS. 4 to 11 show a second embodiment of the long shaft member 20 according to the present invention. 4 to 11, at least one of the shaft portions 23 of the long shaft member 20 is a metal shaft 23 'for receiving rotational power.

FIG. 4 shows a metal shaft 2 at one end (one end) of the main body cavity 28 on the side close to the gas nozzle 32.
The long shaft member 20 formed by inserting 3 'as an insert member is shown. FIG. 5 shows the long shaft member 20 formed by inserting the metal shaft 23 ′ as an insert member at the end (the other end) of the main body cavity 28 on the side closer to the extra resin receiving cavity 34. . FIG. 6 shows the long shaft member 20 formed by inserting metal shafts 23 ′ into both ends of the main body cavity 28 as insert members. The metal shaft 23 'is cylindrical and has a through hole 24 in its axial direction. Here, the metal shaft 23 'is used as the insert member, but a material different from the synthetic resin material forming the main body 21 may be used as the insert member, and the insert member is not limited to metal.

As the molding die, the same one as shown in FIG. 2 can be used. In this case, at least one of the first and second shaft cavities 29 and 30 has a metal shaft 2.
3 'is installed.

That is, the metal shaft 23 ′ is inserted at one end of the main body 21, and the second shaft 23 is formed at the other end of the main body 21 by a synthetic resin material. In the case of FIG. 4), the insert member 23 ′ is installed in the first shaft cavity 29 existing at one end of the main body cavity 28 for molding the main body 21. The gas from the gas pressure source is supplied to the metal shaft 23.
′ Through the through hole 24.

A long shaft member 2 having a metal shaft 23 ′ inserted into the other end of the main body 21 and a first shaft 23 formed of a synthetic resin material at one end of the main body 21.
In the case of 0 (see FIG. 5), the insert member 23 ′ is installed in the second shaft portion cavity 30 existing at the other end of the main body portion cavity 28 for molding the main body portion 21. Further, the extra resin receiving cavity 34 is
′ Through the through hole 24.

In the case of the long shaft member 20 in which metal shafts 23 'are inserted at both ends of the main body 21 (see FIG. 6), the inserts are inserted into both the first and second shaft cavities 29, 30. A member 23 'is installed. Gas nozzle 32
Is communicated with the main body cavity 28 through the through hole 24 of the metal shaft 23 ′ installed in the first shaft cavity 29, and the extra resin receiving cavity 34 is inserted into the insert member 23 installed in the second shaft cavity 30. ´ through hole 2
4 and communicate with the main body cavity 28. The through-hole 24 of the metal shaft 23 'is installed substantially concentrically with the central axis O2. The diameter of the through hole 24 is the same from the end face of the metal shaft 23 ′ exposed from the main body 21 to the end face embedded in the main body 21.

The method of forming the long shaft member 20 shown in FIGS. 4 to 6 will be schematically described with reference to the drawings shown in FIGS. 7 to 10.

FIGS. 7 to 10 show the main unit 2.
5 shows a method of forming a long shaft member 20 (see FIG. 5) in which a metal shaft 23 'is provided at the other end of the long shaft member 20.

First, as shown in FIG. 7, the molten synthetic resin material 4 is injected into the resin injection section 31 from the resin injection passage 33. Then, the synthetic resin material 4 in a molten state is injected from the resin injection part 31 to the one end of the main body part cavity 28 via the first shaft part cavity 29. The injection of the molten synthetic resin material 4 is stopped with a predetermined amount of the molten synthetic resin material 4 injected into the main body cavity 28. That is, the injection of the synthetic resin material 4 in the molten state is stopped by a short shot, or immediately before the injection, a pressurized gas is injected from the gas nozzle 32 into the resin injection unit 31 as shown in FIG.

The molten synthetic resin material 4 is deprived of heat from the contact surface of the molding die and solidified by cooling. However,
The progress of cooling and solidification of the central portion of the synthetic resin material 4 in the molten state is slower than that of the contact surface. Therefore, the synthetic resin material 4 in the molten state at the central portion where cooling and solidification is slow is moved while expanding toward the other end of the main body cavity 28 by the pressure of the pressurized gas. Due to the pressure of the pressurized gas, the synthetic resin material 4 in the molten state passes through the other end of the main body cavity 28, the through hole 24 of the metal shaft 23 ', and the connection passage 35 as shown in FIG. Is moved toward the extra resin receiving cavity 34. Further, the synthetic resin material 4 in the molten state is compressed by the pressure of the pressurized gas into the body portion cavity 2
8, and a hollow portion 22 is formed therein. The change in the hollow ratio is caused by the extra resin receiving cavity 34.
Is absorbed by

Since the synthetic resin material 4 in the molten state is guided to the extra resin receiving cavity 34 through the through hole 24 of the metal shaft 23 ', the through hole 2 of the metal shaft 23'
4 is covered with the synthetic resin material 4 integral with the main body 21. Therefore, the metal shaft 23 'at the other end of the main body 21 and the main body 21
Therefore, the contact area with the contact hole increases, and the tensile strength in the axial direction increases.

The molded product 20 'taken out of the molding die
As shown in FIG. 10, since the meat portions 31 'and 35' and the surplus portion 34 'are integrally formed, these are cut to form the long shaft member 20 shown in FIG.

FIG. 11 shows a long shaft member 20 in which metal shafts 23 ′ are inserted into both ends of a main body cavity 28.
FIG. 7 is an explanatory view in the case of molding (see FIG. 6). When the long shaft member 20 shown in FIG. 6 is formed, a predetermined amount of the synthetic resin material in a molten state is passed through the through hole 24 of the metal shaft 23 ′ installed in the first shaft cavity 29. 28. Then, immediately before or immediately after the injection of the molten synthetic resin material is stopped, gas is injected into the main body cavity 28 through the through hole 24 of the metal shaft 23 '. The inner peripheral wall forming the through hole 24 of the metal shaft 23 ′ installed in the first shaft portion cavity 29 is covered with the synthetic resin material 4 integrated with the main body 21. Therefore, the contact area between the metal shaft 23 'at one end of the main body 21 and the main body 21 also increases, and the tensile strength in the axial direction increases.

[0053]

Third Embodiment FIGS. 12 to 15 show a third embodiment of the long shaft member 20 according to the present invention. This FIG. 12 to FIG.
In this embodiment, both ends of the shaft portion 23 of the long shaft member 20 are formed as metal shafts 23 ′ for receiving rotational power, and the diameter of the through hole 24 of the metal shaft 23 ′ is
′ Continuously increases from the end face exposed to the outside to the end face embedded in the main body 21.
That is, the inner peripheral wall that forms the through hole 24 of the metal shaft 23 ′ has a conical shape (tapered shape).

To form the long shaft member 20, FIG.
A metal shaft 23 'having a tapered through-hole 24 is set in the cavities 29, 30 as shown in FIG.
Next, as shown in FIG. 14, the tapered through hole 2
The synthetic resin material 4 in a molten state is injected into the main body cavity 28 through 4. Since the cross-sectional area of the through hole 24 increases toward the body cavity 28, FIGS.
The pressure loss can be reduced as compared with the case of using the metal shaft 23 'having the shape shown in FIG.
Can be injected.

Next, in FIG. 15, a gas is injected from the direction of the central axis O2, and the synthetic resin material 4 in a molten state is spread all over the corners of the main body cavity 28. Even when the gas is injected, the cross-sectional area of the through-hole 24 is
8, the pressure loss can be reduced, and gas can be injected into the main body cavity 28 with little loss of gas pressure. That is, since the gas is injected while spreading toward the main body cavity 28, the gas is injected into the main body cavity 2.
It will flow into Sooms in 8.

In the metal shaft 23 ′ set in the cavity 30 existing at the other end of the main body cavity 28, the cross-sectional area of the through hole 24 is
8, the pressure becomes narrower as the synthetic resin material 4 in the molten state is pushed into the excess resin receiving cavity 34 because the width becomes narrower toward the excess resin receiving cavity 34. The synthetic resin material in the state is smoothly moved to the extra resin receiving cavity 34.

In this embodiment, the tapered through hole 24
Body 21 with metal shaft 23 ′ having
Are provided on both sides of the tapered through hole 24.
May be provided on only one of the shafts, and the other shaft may be made of a synthetic resin material.

[0058]

Fourth Embodiment FIGS. 19 and 20 show a long axis member 20 in which a helical projection 25 formed on the outer periphery of a main body 21 along its longitudinal direction is asymmetric in the circumferential direction with respect to a center axis O1. ing. In the case of the long shaft member 20, as shown in FIG. 19, the center O 1 ′ of the hollow portion 22 and the plurality of protrusions 25
20 is shifted from the center axis O1 which is the center of the contour shape of the portion of the main body portion 21, and as shown in FIG. 20, the protrusion missing portion 21 'of the main body portion 21 tends to be thick.
This is because the synthetic resin material 4 in the molten state on the side where the projections are formed is large, so that the synthetic resin material 4 in the molten state existing on the side where the projections are formed is hardly cooled and hardened. For this reason, the main body 21 may be bowed, and the long shaft member 20 may be bent.

Therefore, as shown in FIGS. 16, 17 and 18, the main body 21 having a plurality of projections 25 formed thereon is provided.
The lightening portion 36 is formed from one side to the other in the longitudinal projection forming region 21A on the outer peripheral surface of the above. Accordingly, the center of the contour of the main body 21 is aligned with the center axis so that the center O1 'of the hollow portion 22 and the center of the contour of the main body 21 where the plurality of protrusions 25 are formed coincide with each other. It is shifted from O1.

As described above, a plurality of asymmetric projections 25
Is formed from one side of the main body 21 where the
If the lightening portion 36 is formed, the thickness of the main body portion 21 becomes uniform from one side to the other side at a portion where the plurality of asymmetrical projections 25 are formed, so that the straight length is reduced. The shaft member 20 can be formed.

That is, the protrusion forming portion 21B is present in the longitudinal protrusion forming region 21A at a predetermined interval in the longitudinal direction, within a predetermined circumferential angle range, and at a position outside the predetermined angular range, the protrusion missing portion is provided. There is a projection non-forming portion as 21 '. Therefore, if the lightening portion 36 having an outer peripheral surface lower than the outer peripheral surface of the base of the projection forming portion 21B is formed in the non-projection forming portion of the longitudinal projection forming region 21A, the cross-sectional thickness of the non-projection forming portion is reduced. The cross-sectional thickness of the projection forming portion is substantially the same.

[0062]

[Embodiment 5] Fig. 21 is a schematic view of the entire configuration of a molding device for a long shaft member 20 according to the present invention.

In FIG. 21, reference numeral 40 denotes an injection molding machine main body (resin filling device or resin filling means). A hopper 41 is provided in the injection molding machine main body 40, and solid pellets 42 are stored in the hopper 41. The pellets 42 are supplied in a predetermined amount to a pressure melting chamber 42b of a cylinder 42a, and are converted into a synthetic resin material 4 'in a molten state by a screw rod 42c. The molten synthetic resin material 4 ′ is guided to the resin injection section 31 through the resin injection paths 43 and 33 of the fixed mold 26. The molding dies 26 and 27 near the gas nozzle 32 and the main body cavity 2
As shown in FIG. 22, a water cooling passage (temperature control member) 44 for controlling the temperature in the vicinity of the gas nozzle and a water cooling passage (temperature control member) for controlling the temperature of the main body cavity are provided in the vicinity of the molding die 8. A passage (temperature control member) 45 is formed. The temperature of the cooling water supplied to the water cooling passage 44 is 5
The temperature is set to 0 degrees, and the temperature of the cooling water supplied to the water cooling passage 45 is set to 10 degrees. Thus, the cooling temperature of the molding dies 26 and 27 near the gas nozzle 32 is set to a higher temperature than the cooling temperature of the molding dies near the main body cavity 28. The temperature of the temperature adjusting member is controlled by temperature adjusting means 40B and 40C described later.

This is based on the following reasons.

The molten synthetic resin material 4 is cooled by contact with the inner peripheral wall of the main body cavity 28. However, gas is supplied to the central portion of the synthetic resin material 4 in a molten state, and is not forcibly cooled. Therefore, if the molten synthetic resin material 4 is cooled only depending on the contact with the inner peripheral wall of the main body cavity 28, a long cooling time is required and the molding cost of the long shaft member 20 is increased. Therefore, in general, a molding cycle is shortened by forcibly cooling a molding die using a cooler (chiller).

However, if the temperature of the molding die near the gas nozzle 32 is to be cooled at the same temperature as that of the molding die near the main body cavity 28, the molten synthetic resin material Even if the pressurized gas is injected because the hardening of the synthetic resin material 4 due to cooling progresses too much, the synthetic resin material 4 in the molten state does not expand, and a hollow portion may not be formed in the synthetic resin material 4 in the molten state.

In order to suppress the curing speed of the molten synthetic resin material 4 near the gas nozzle 32 while shortening the molding cycle of the long shaft member 20, the molding dies 26, 27 near the gas nozzle 32. The cooling temperature of the part
The temperature was set to be higher than the cooling temperature of the molding die near the main body cavity 28.

The reason that the temperature of the cooling water supplied to the water cooling passage 45 is set to 10 degrees is that if the mold is cooled at a temperature lower than this, the cooling and solidification of the synthetic resin material 4 in the molten state proceeds. The movement stops before the synthetic resin material 4 in the molten state does not reach the excess resin receiving cavity 34,
This is because the desired shape of the long axis member 20 cannot be obtained.

The reason why the temperature of the cooling water supplied to the water cooling passage 44 is set to 50 degrees is that if the mold is cooled at a temperature lower than this, cooling and solidification of the synthetic resin material 4 in the molten state proceeds. This is because even if the pressurized gas is injected, the synthetic resin material 4 in the molten state does not expand, and the pressurized gas is hardly injected into the main body cavity 28. On the other hand, if the mold is cooled at a temperature higher than this, the temperature of the mold near the gas nozzle 32 is too high, and
Fluidity is increased. Therefore, when a gas is injected, the synthetic resin material 4 in a molten state may be blown off by the injection of the gas. Therefore, the temperature of the synthetic resin material 4 in the molten state in the vicinity of the gas nozzle 32 is set to 50 ° C. as a temperature at which the temperature is equal to or higher than the glass transition point and no blow-off occurs due to gas injection.

Control of start and end of injection filling for each molding cycle, control of water supply of cooling water to the injection molding machine main body 40, water cooling passages 44 and 45, injection of gas into the main body cavity 28, and The control for degassing is C
Performed by the PU. The CPU opens the molding die,
These controls are performed in conjunction with mold clamping.

That is, as shown in FIG. 23, the CPU executes the injection molding machine main body 40, the molding die driving means 40A, and the like via the input output interface.
The main body cavity temperature control means 40B, the gas nozzle vicinity temperature control means 40C, and the gas injection and gas release means (medium injection device) 40D are controlled.

The temperature control means (temperature control device) 40
B and 40C are operated at least until the hollow forming medium passes through the molten resin filled in the first shaft portion cavity 29 and is injected into the molten resin 4 filled in the main body cavity 28.

[0073]

Embodiment 6 The details of the method of forming the long shaft member 20 by this forming apparatus will be described below.

In the sixth embodiment, the case where the long shaft member 20 shown in FIG. 5 is formed is described. However, the present invention can also be applied to the molding of the long shaft member 20 shown in FIGS. 1, 4, 6, and 12.

First, as shown in FIG. 24A, the metal shaft 23 'is set in a molding die, and the die is closed (see step S1 in FIG. 25). Then, the synthetic resin material 4 in a molten state is injected into the main body cavity 28 at a predetermined pressure (see steps S2 and S3 in FIG. 25). That is, the synthetic resin material 4 in a molten state is injected by a short shot.

As the synthetic resin material 4, for example, ABS is used. If the viscosity of the synthetic resin material 4 in the molten state is too low, the mass of the synthetic resin material 4 in the molten state is broken through by the pressurized gas, and the pressurized gas is released from the main body cavity 28.
And a molded product 20 'having a desired shape cannot be obtained. On the other hand, if the viscosity of the synthetic resin material 4 in the molten state is too high, the synthetic resin material 4 in the molten state does not swell smoothly due to the pressurized gas, and a desired hollow molded product 20 'cannot be obtained.
Further, it is necessary to consider the rigidity of the long shaft member 20 'as a finished product. Thus, here, glass fibers are mixed with ABS resin. The glass fiber content was 30% by weight. The fiber length of the glass fiber is 3m on average
m, the fiber diameter is 13 μm on average.

When the moldability was evaluated using the ABS resins having different viscosities (international test method standard (abbreviated as ASTM)), the following results were obtained.

Here, the product name N manufactured by Techno Polymer Co., Ltd.
A comparison was made between two types of ABS resins, C411-G30 and NC100-G30. In each case, the glass fiber content was 30% by weight. Product name NC411-G
No. 30 has a viscosity of 12.0 g / min at a melt flow rate of 220 degrees and 98 N, and has a high viscosity. On the other hand, the product name NC100-G30 has a melt flow rate of 220.
The viscosity is 40.0 g / min under low temperature and 98 N, and the viscosity is low.

A molding experiment was performed on these two types of ABS. As a result, uneven thickness occurred in the ABS resin having a high viscosity of the synthetic resin material 4. AB with low viscosity of synthetic resin material 4
In S resin, uneven thickness did not occur.

This is because, as shown in FIG. 26A, when the viscosity of the synthetic resin material 4 is high, the gas inflow direction is bent relative to the central axis O2 near the resin injection portion 31. Can be On the other hand, as shown in FIG. 26B, when the viscosity of the synthetic resin material 4 is low, the gas pressure overcomes the viscosity of the synthetic resin material 4, and the gas inflow direction becomes parallel to the central axis O2. it is conceivable that.

The temperature of the synthetic resin material 4 in the molten state is, for example, 240 degrees. The injection amount of the synthetic resin material 4 in the molten state is desirably about 70% of the volume of the main body cavity 28. However, the injection amount of the molten resin injected by the resin injection device and the injection of the medium by the medium injection device. The sum of the injection amount of the hollow forming medium and the volume of the main body cavity 28 formed in the molding die and the first and second shaft cavities 29 and 30 need only be equal to or greater than the total.

Next, as shown in FIG. 24B, a gas is injected into the resin injection portion 31 from the direction of the central axis O2 immediately before or immediately after the injection of the molten synthetic resin material 4 is stopped. Then, the synthetic resin material 4 in the molten state is moved toward the extra resin receiving cavity 34 while expanding, and the synthetic resin material 4 in the molten state is spread over the entire inner surface of the main body cavity 28. By the injection of the gas from the direction of the central axis O2, a hollow portion 22 extending long in the direction of the central axis O2 is formed. The extra molten synthetic resin material 4 is guided to the extra resin receiving cavity 34, thereby absorbing the fluctuation of the hollow ratio.

The gas pressure is 50 to 300 kg / cm ^2.
Can be selected within the range, but here, 110 kg /
The injection was performed at a pressure of cm ² . If the gas pressure is too low, a molded article 20 ′ having a sufficiently hollow shape cannot be obtained. If the gas pressure is too high, the pressurized gas breaks through the molten synthetic resin material 4 and leaks into the main body cavity 28. The molded product 20 'having the desired shape cannot be obtained.
Preferably, a predetermined pressure of cm ² is applied.

Then, the gas pressure is maintained for a certain time.
As a result, the molten synthetic resin material 4 spread over the entire inner surface of the main body cavity 28 is cooled and solidified (FIG. 2).
5 steps S4 and S5). Here, the long shaft member 2
The gas pressure holding time was set to 40 seconds, taking into account the dimensional accuracy of 0 and the shortening of the molding cycle. At least, the surface of the molded article 20 'is cooled to the glass transition point temperature or lower, and when the molded article 20' is protruded, the molded article 20 'is not deformed due to shrinkage after removing the molded article 20'.
Need to be cooled and cured in a mold.

That is, the gas pressure holding time and the molded product 20 ′
The relationship shown in the graph of FIG. In FIG. 27 (a),
The horizontal axis represents the gas holding time and the vertical axis represents the dimensional accuracy of the long shaft member 20. Here, the rotational runout of the long shaft member 20 was used as the dimensional accuracy of the long shaft member 20.

That is, the needle is brought into contact with the outer peripheral surface of the main body 21 with reference to the first and second shafts 23,
The maximum amount of change of the needle when the was rotated once was measured.

In FIG. 27A, the code Q0 is
This is a characteristic curve showing the relationship between the gas pressure holding time and the dimensional accuracy of the molded product 20 ′. In the region Q 1 where the pressure holding time is short, the cooling and solidification of the synthetic resin material 4 in the molten state is insufficient. When the product 20 'is removed from the mold, the molded product 20'
Is greatly deformed by cooling and solidification of the synthetic resin material 4, and the dimensional accuracy of the molded product 20 'is reduced. Also, as shown in FIG. 27B, the main body cavity 2 near the gas nozzle 32 is formed.
A part of the synthetic resin material in the molten state, which has not been cooled and solidified, in the gas nozzle 3 by the wind pressure at the time of degassing described later.
2, the gas nozzle 32 may be clogged.

On the other hand, in the region Q2 where the dwell time is long, the dimensional accuracy of the long shaft member 20 is improved. However, biting of the molded product due to shrinkage of the molded product is increased, and mold release failure occurs when removing the molded product 20 ′. Therefore, the molded product 20
It may break when removing '.

Therefore, the pressure holding time of the gas in the hollow portion 22 is set in consideration of the dimensional accuracy of the long shaft member 20 and the degree of progress of the hardening of the molten synthetic resin material.

During the holding of the gas, the pellets 42 are weighed on the side of the molding machine main body 40 for the production of the next molded article. At this time, in order to improve the measurement accuracy, a back pressure (in the injection passage 33 of the resin injection section 31) is applied to the synthetic resin material 4 'in the molten state stored in the pressurized melting chamber 42b on the molding machine main body 40 side by the screw rod 42c. (The pressure at which the molten resin stays). When the back pressure P0 is higher than the gas holding pressure P1, as shown in FIG.
A part of the synthetic resin material 4 ′ in the molten state existing in the injection passage 33 leaks out to the resin injection part 31 and closes a part of the through hole 24. Therefore, the gas holding pressure P1 is set to the back pressure P
Set larger than 0. As described above, when the gas holding pressure P1 is set to be higher than the back pressure P0, FIG.
As shown in the figure, the molten synthetic resin material 4 ′ existing in the injection passage 33 is pushed into the injection passage 33 and
4 can be prevented from being blocked. This stopping pressure is determined by the CPU
(Control device).

That is, the injection pressure of the medium injection device 40D is also controlled by the CPU, and this pressure P1 is higher than the stop pressure P0. The operation of the medium injection device 40D is preferably performed until the inner surface of the molten resin 4 is stabilized.

The stability of the inner surface of the molten resin 4 is based on the fact that the temperature of the inner surface of the molten resin existing at a position communicating with the molten resin existing in the first shaft portion cavity 29 and the molten resin existing in the main body cavity. It is determined by a temperature below the softening point.

Next, as shown in FIG. 24 (c), since the gas pressure in the hollow portion 22 is much higher than the external pressure,
Hollow portion 22 of molded product 20 'cooled and solidified in a molding die
The gas accumulated inside is extracted from the gas nozzle 32 (FIG. 25
S6 and S7). The medium injection device 40D also functions as a device for removing the gas.

Then, the molded product 20 'is removed from the molding die (see S8 in FIG. 25).

Next, as shown in FIG. 23 (d), unnecessary parts of the molded product 20 'are cut to complete the long shaft member 20 shown in FIG. 24 (e).

[0096]

Seventh Embodiment FIGS. 29, 30 and 31 show another embodiment of a molding apparatus and a molding method for a long shaft member according to the present invention.

In this embodiment, a hollow forming medium outflow portion (hole or pipe) 40E which is open to the inner wall of the extra resin receiving cavity 34 is provided in the fixed mold 26. The reason why the hollow forming medium outflow portion 40E is provided in the fixed mold 26 is that the configuration is simple.

[0098] The hollow forming medium outflow portion 40E may have a configuration in which the tip 40G protrudes into the hollow 34 'of the extra resin receiving cavity 34. Hollow forming medium outlet 40E
An opening / closing valve (outflow opening / closing control means) 40F is provided in the middle of the process. The opening and closing valve 40F is controlled by the CPU so that the hollow 34 'has a desired size.
To prevent the gas from flowing out of the hollow forming medium outflow portion 40E for a certain period of time, the on-off valve 40F is closed. When the tip 40G of the hollow forming medium outflow portion 40E is flush with the inner wall surface of the extra resin receiving cavity 34, the CPU determines that the gas does not escape from the hollow forming medium outflow portion 40E due to the gas piercing the molten resin 4 due to the gas pressure. The opening / closing valve 40F may be opened when it is hardened.

In this embodiment, the gas is allowed to flow out in a direction perpendicular to the gas injection direction. However, the hollow forming medium outflow opening at the innermost wall surface 40H at the innermost part in the gas injection direction of the extra resin receiving cavity 34. When the molten resin spreads over the inner surfaces of the molded product cavities 28, 29, and 30 to form the molded product 20 'having a desired shape and the inner surface of the molten resin is in a desired hardened state, the gas is supplied. The pressure of the gas in the hollow portion 22 is increased by the injection / degassing means 40D, and the gas is pierced through the molten resin filled in the excess resin receiving cavity 34 and the gas is discharged into the hollow forming medium outlet 40E.
May be drained from In this case, the gas injection / gas release means 40D functions as a gas pressure variable means.

FIG. 31 shows a molding method according to this embodiment.
As shown in (a), it is preferable to inject the molten resin 4 into the molded article cavity with the open / close valve 40F opened by the CPU, but the molten resin 4 may be poured with the open / close valve 40F closed. .

Next, as shown in FIG.
To close the open / close valve 40F, and pressurized gas is injected into the molten resin in the molded product cavity. Since the hollow forming medium outlet 40E is closed by the opening / closing valve 40F, the gas is prevented from flowing out from the hollow forming medium outlet 40E, and a molded article having a desired shape is formed. Next, after a lapse of a predetermined time, the opening and closing valve 40F is opened by the CPU as shown in FIG. As a result, the gas flows out of the hollow forming medium outlet 40E. The remaining steps (FIG. 31)
(D) and FIG. 31 (e) are the same as the steps described above, and thus the description thereof will be omitted.

[0102]

According to the molding apparatus and the molding method for a long shaft member according to the present invention, a hollow forming medium is injected from the center axis direction of a molded product cavity to expand a molten synthetic resin material while forming a molded product cavity. Pressing to form a hollow portion, and guiding the excess molten synthetic resin material in the molded product cavity to the extra resin receiving cavity, thereby discharging the excess molten synthetic resin material from the molded product cavity. It is possible to manufacture a long-axis member with good accuracy and little bending deformation.

Further, since the holding pressure of the hollow forming medium in the hollow portion is set to be larger than the back pressure (resting pressure) of the molding machine main body side, the holding pressure of the hollow forming medium from the forming machine main body side is maintained. This prevents the molten synthetic resin material from flowing in and closing the through hole.

Further, since the dwell time is selected in consideration of the dimensional accuracy of the long shaft member and the degree of progress of the curing of the synthetic resin material in the molten state, the occurrence of molding defects can be avoided as much as possible.

In a molding apparatus in which the cooling temperature in the vicinity of the gas nozzle of the molding die is set higher than the cooling temperature in the vicinity of the molded product cavity, the melting cycle in the vicinity of the gas nozzle is reduced while shortening the molding cycle of the long shaft member. The curing speed of the synthetic resin material in the state can be suppressed, and when the gas is injected into the synthetic resin material in the molten state, the gas can be smoothly injected into the synthetic resin material in the molten state.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a long shaft member according to the present invention.

FIG. 2 is a partial sectional view of a mold for molding the long shaft member shown in FIG.

FIG. 3 is a longitudinal sectional view of a molded product formed by a molding die for a long shaft member shown in FIG. 2;

FIG. 4 is a longitudinal sectional view of a long shaft member according to the present invention, showing a long shaft member in which one shaft portion is made of an insert member.

FIG. 5 is a longitudinal sectional view of the long shaft member according to the present invention, and shows the long shaft member in which the other shaft portion is made of an insert member.

FIG. 6 is a longitudinal sectional view of a long shaft member according to the present invention, showing a long shaft member in which shaft portions at both ends are made of an insert member.

FIG. 7 is a partial cross-sectional view of the molding die for the long shaft member shown in FIG. 5, showing a state in which a synthetic resin material in a molten state is injected into a molded product cavity.

FIG. 8 shows a state in which a pressurized gas is injected into the molten synthetic resin material shown in FIG. 7 to expand the molten synthetic resin material.

9 is a partially enlarged sectional view of the vicinity of an extra resin receiving cavity of the molding die shown in FIG.

FIG. 10 is a longitudinal sectional view showing a molded product molded by a molding die of the long shaft member shown in FIG. 7;

FIG. 11 is a longitudinal sectional view showing an example of a forming process of a long shaft member in which shaft portions at both ends are made of an insert member.

FIG. 12 is a cross-sectional view of the long shaft member according to the present invention, showing the long shaft member made of an insert member having shaft portions at both ends having tapered through holes.

13 is a partial vertical sectional view of a molding die used for molding the long shaft member shown in FIG.

14 is a partial cross-sectional view of the molding die for the long shaft member shown in FIG. 12, showing a state in which a synthetic resin material in a molten state is injected into a molded product cavity.

15 shows a state in which a pressurized gas is injected into the molten synthetic resin material shown in FIG. 14 to expand the molten synthetic resin material.

FIG. 16 is a longitudinal sectional view of another embodiment of the long shaft member according to the present invention, in which a rotationally asymmetric projection is formed in a circumferential direction of the long shaft member, and a part of the long shaft member is lightened. .

FIG. 17 is a sectional view taken along the line XX of FIG. 16;

18 is a detailed perspective view showing the entire shape of the long shaft member shown in FIG.

FIG. 19 is a longitudinal sectional view of a long shaft member having a rotation asymmetric projection formed in a circumferential direction of the long shaft member, and shows the long shaft member without a lightening;

FIG. 20 is a cross-sectional view taken along line YY of FIG. 19;

FIG. 21 is an explanatory view showing a schematic configuration of a molding apparatus used for molding a long shaft member according to the present invention.

FIG. 22 is a partially enlarged view of the molding die shown in FIG. 21 and is an explanatory view of a water cooling passage.

FIG. 23 is a block diagram illustrating a relationship between a CPU and each control unit.

FIG. 24 is an explanatory view showing an example of a molding method of a long shaft member according to the present invention, wherein (a) shows a state in which a synthetic resin material in a molten state is injected into a molded product cavity of a molding die; (B) shows a state in which a pressurized gas is injected into the molten synthetic resin material, the pressure is maintained for a predetermined time, and the material is cooled and solidified,
(C) shows a state in which the pressurized gas present in the hollow part of the molded article formed by cooling and solidifying is degassed,
(D) is a cross-sectional view of the molded product taken out of the molding die, and (e) shows a long shaft member formed by cutting an unnecessary portion of the molded product.

FIG. 25 is a flowchart showing steps of a method of forming a long shaft member.

26A and 26B are enlarged views of the vicinity of a gas nozzle of a molding die, wherein FIG. 26A shows a gas flow path when a synthetic resin material used for molding the long shaft member has a high viscosity, and FIG. 2 shows a gas flow path when the viscosity of a synthetic resin material used for molding of the resin is low.

FIGS. 27A and 27B are explanatory diagrams illustrating the relationship between the gas holding pressure time and the dimensional accuracy of the long shaft member, and FIG. 27A is a characteristic curve diagram illustrating the relationship between the gas holding pressure time and the dimensional accuracy of the long shaft member. (B) is a partially enlarged view of a molding die near a gas nozzle, and is an explanatory view for explaining a problem when the gas holding time is short.

FIG. 28 is an enlarged view of the vicinity of a gas nozzle of a molding die for explaining a relationship between a back pressure applied to a synthetic resin material in a molten state on a molding machine main body side and a holding pressure of a pressurized gas;
(A) shows a state in which the resin injection portion is closed because the back pressure is higher than the holding pressure of the pressurized gas, and (b) shows that the back pressure is lower than the holding pressure of the pressurized gas. Thus, a state in which the resin injection portion is not closed is shown.

FIG. 29 is an explanatory view showing another embodiment of a molding device for a long shaft member according to the present invention, and showing a schematic configuration of a molding device used for molding a long shaft member according to the present invention.

FIG. 30 is a block diagram showing another embodiment of the long shaft member forming apparatus according to the present invention, showing the relationship between the CPU and each control means.

FIG. 31 is an explanatory view showing another example of a method of molding a long shaft member according to the present invention, wherein (a) shows a state in which a synthetic resin material in a molten state is injected into a molded product cavity of a molding die. (B) shows a state in which a pressurized gas is injected into the molten synthetic resin material, the pressure is maintained for a predetermined time, and the material is cooled and solidified,
(C) shows a state in which the gas of the pressurized gas existing in the hollow portion of the molded product formed by the cooling and solidification flows out,
(D) is a cross-sectional view of the molded product taken out of the molding die, and (e) shows a long shaft member formed by cutting an unnecessary portion of the molded product.

FIG. 32 is a partial cross-sectional view showing a step of forming a long shaft member using a conventional long shaft member forming die.

FIG. 33 is a cross-sectional view showing an example of a long shaft member formed by a conventional long shaft member molding die.

FIG. 34 is a partial cross-sectional view showing a step of forming a long shaft member having an insert member inserted at one end using a conventional long shaft member molding die.

FIG. 35 is a cross-sectional view showing a step of forming a long shaft member having insert members inserted at both ends using a conventional long shaft member molding die.

[Explanation of symbols]

 4: Synthetic resin material in a molten state 20: Long shaft member 21: Main body 22: Hollow hole 23: Shaft 23 ': Metal shaft 24: Through hole 28: Main body cavity 32: Gas nozzle 34: Extra resin receiving cavity O1 ... Center axis of rotation O2 ... Center axis of cavity

Claims (22)

[Claims] 1. A main body formed of a synthetic resin material has a hollow portion extending substantially in a direction substantially concentric with a central axis and extending in a direction in which the central axis extends. A first shaft portion and a second shaft portion having a small diameter are formed, and a through hole is formed in each of the shaft portions to communicate the hollow portion to the outside; and the through hole is substantially concentric with the central axis. A molding device having a cavity center axis corresponding to the central axis of the body portion to mold the body portion, and a first and a second body for molding the first and second shaft portions. A second shaft cavity, a medium injection unit for injecting a hollow forming medium for forming the hollow along the central axis through the first shaft cavity, and a medium injection unit provided on the cavity side with respect to the medium injection unit. Resin injection part for injection of molten resin, and A molding die having at least an extra resin receiving cavity for receiving, through the second shaft portion cavity, an extra resin that becomes excess in the cavity due to the injection of the hollow forming medium from the charged molten resin; A medium injecting device for injecting the hollow forming medium at a predetermined pressure from a resin filling device for filling the molten resin into the cavity at a predetermined pressure from the resin injecting section. Shaft member forming device. 2. The resin filling device is controlled by a controller that injects a predetermined amount of molten resin into a cavity by a predetermined pressure, and then sets a stop pressure at which the molten resin stops at the resin injection section. The medium injection device is configured such that the medium injection pressure is controlled by a medium control device that injects the hollow forming medium after the predetermined amount of the molten resin is injected into the cavity by the resin filling device, and the medium injection pressure is stopped. The molding device for a long shaft member according to claim 1, wherein the pressure is equal to or higher than the pressure. 3. After the injection of a predetermined amount of molten resin from the resin filling device into the cavity is completed, the hollow forming medium is injected into the molten resin, and the hollow resin is hollowed out by the hollow forming medium. The molding device for a long shaft member according to claim 1, further comprising a medium injection control device that operates the medium injection device until the inner surface of the long axis is stabilized. 4. The stability of the inner surface of the molten resin is determined by the first
It is characterized in that the temperature of the inner surface of the molten resin present at a place communicating with the molten resin present in the shaft cavity and the molten resin present in the main body cavity becomes a temperature equal to or lower than the softening point. The apparatus for forming a long shaft member according to claim 3. 5. A removal method for removing the hollow forming medium from the hollow portion by injecting the hollow forming medium from the first shaft portion cavity through the main body portion cavity to the second shaft portion cavity by the medium injection device. The apparatus for forming a long shaft member according to claim 1, further comprising an apparatus. 6. The total of the filling amount of the molten resin injected by the resin filling device and the injection amount of the hollow forming medium injected by the medium injection device is the main body portion formed in the molding die. 2. The molding device for a long shaft member according to claim 1, wherein the length of the long shaft member is equal to or greater than the sum of the volume of the cavity and the volumes of the first and second shaft cavities. 7. The apparatus according to claim 1, wherein the hollow forming medium is a gas or a liquid. 8. The long shaft member according to claim 1, wherein an insert member having a through hole concentric with the center of the shaft portion is installed in the first shaft portion cavity or the second shaft portion cavity. Molding equipment. 9. The apparatus for forming a long shaft member according to claim 8, wherein the through hole has a conical shape whose diameter gradually increases toward the main body cavity. 10. The first shaft cavity and the second shaft cavity.
2. An insert member having a through hole concentric with the center of the shaft portion is installed in the shaft cavity.
A molding device for forming a long shaft member according to item 1. 11. The long shaft member forming apparatus according to claim 10, wherein the through hole has a conical shape whose diameter gradually increases toward the main body cavity. 12. A temperature control member is disposed in the vicinity of the medium injection section, and the temperature adjustment member is controlled by a temperature control device such that the molten resin of the medium injection section filled from the resin filling device maintains a molten state. The apparatus for forming a long shaft member according to claim 1, which is controlled. 13. The temperature control device, wherein at least the hollow forming medium passes through the molten resin filled in the first shaft portion cavity and is injected into the molten resin filled in the main body cavity. The apparatus for forming a long shaft member according to claim 12, wherein the apparatus operates. 14. A main body formed of a synthetic resin material has therein a hollow portion which is substantially concentric with the central axis and extends in the direction in which the central axis extends, and is provided at both ends of the main body with respect to the main body. A first shaft portion and a second shaft portion having a small diameter are formed, and a through hole communicating the hollow portion to the outside is formed in each of the shaft portions,
A molding device for a long-axis member, wherein the through-hole is substantially concentric with the central axis, wherein a main-body cavity having a cavity central axis corresponding to the central axis of the main body to mold the main body; Medium for injecting first and second shaft cavities for molding first and second shafts and a hollow forming medium for forming the hollow along the central axis through the first shaft cavities. An injection portion, a resin injection portion for injecting molten resin provided on the cavity side with respect to the medium injection portion, and an extra portion in the cavity due to injection of the hollow forming medium among the molten resin filled in the cavity. A molding die having at least an extra resin receiving cavity for receiving extra resin through the second shaft portion cavity, and injecting the hollow forming medium at a predetermined pressure from the medium injecting portion. A medium injection means, the molding apparatus of longitudinal members of the molten resin at a predetermined pressure from the resin injection portion and a resin filling means for filling in the cavity. 15. A main body formed of a synthetic resin material has therein a hollow portion which is substantially concentric with the central axis and extends in the direction in which the central axis extends. A first shaft portion and a second shaft portion having a small diameter are formed, and a through hole communicating the hollow portion to the outside is formed in each of the shaft portions,
A molding device for a long-axis member, wherein the through-hole is substantially concentric with the central axis, wherein a main-body cavity having a cavity central axis corresponding to the central axis of the main body to mold the main body; First and second shank cavities for molding first and second shank portions formed at both end portions of the main body portion, and a hollow forming medium for forming the hollow portion along the central axis. A medium injection portion to be injected through the first shaft portion cavity, a resin injection portion for injection of molten resin provided on the cavity side with respect to the medium injection portion, and the hollow forming medium of the molten resin filled in the cavity. For receiving the extra resin that becomes extra in the cavity due to the injection of the resin, the extra resin receiving cavity received through the second shaft cavity, and the second shaft cavity of the extra resin receiving cavity. A molding die having a medium outflow portion for allowing the hollow forming medium to flow out from the side opposite to the side communicating with the tee, and for injecting the hollow forming medium at a predetermined pressure from the medium injection portion. A molding device for a long shaft member, comprising: a medium injection device; and a resin filling device for filling the molten resin into the cavity at a predetermined pressure from the resin injection portion. 16. The medium outflow portion is opened by opening / closing means when the molten resin filled in the excess resin receiving cavity is in a desired cured state, and the hollow forming medium flows out through the medium outflow portion. 16. The method according to claim 15, wherein
A molding device for forming a long shaft member according to item 1. 17. The resin filling device is controlled by a control device that injects a predetermined amount of molten resin into a cavity by a predetermined pressure and then sets a stop pressure at which the molten resin stops at the resin injection section. The medium injection device is configured such that the medium injection pressure is controlled by a medium control device that injects the hollow forming medium after the predetermined amount of the molten resin is injected into the cavity by the resin filling device, and the medium injection pressure is stopped. 16. The pressure which is higher than the pressure and at which the hollow forming medium can flow through the molten resin to the outflow portion when the molten resin filled in the excess resin receiving cavity is in a desired cured state. A molding device for forming a long shaft member according to item 1. 18. A main body portion formed of a synthetic resin material has a hollow portion extending substantially in the direction in which the central axis extends substantially concentrically with the central axis, and both end portions of the main body portion are located closer to the both ends than the main body portion. First and second shaft portions having a small diameter are formed, and a through hole is formed in each of the shaft portions so as to communicate the hollow portion to the outside, and the long hole member is formed such that the through holes are substantially concentric with the central axis. A method comprising the steps of: forming a cavity center axis corresponding to the center axis of the long axis member, and intersecting the center axis with a resin injection portion formed at one end of a main body cavity for molding the long axis member. A resin injecting step of injecting a synthetic resin material in a molten state from a direction in which the synthetic resin material in a molten state is injected from a direction parallel to the central axis to press the molten synthetic resin material against an inner wall of the main body cavity; The main body cavity while forming a hollow portion Moving from one end toward the other end, leads to a synthetic resin material extra molten state from the other end of the body portion the cavity in excess resin receiving cavity,
A hollow forming medium injecting step of maintaining the pressure of the hollow forming medium at a predetermined value, and cooling and hardening at least the inner surface and the outer surface of the synthetic resin material in the molten state, and thereafter, taking out a molded product from the cavity. A method for forming a long shaft member, comprising: 19. The molding of a long shaft member according to claim 18, wherein a removing step of removing the hollow forming medium in the hollow portion is provided between the hollow forming medium injection step and the removing step. Method. 20. A time for keeping the pressure of the hollow forming medium in the hollow portion constant is set in consideration of the dimensional accuracy of the long shaft member and the degree of progress of the curing of the synthetic resin material in the molten state. The method for forming a long shaft member according to claim 18. 21. The method according to claim 18, wherein the hollow forming medium is injected immediately before or immediately after the injection of the synthetic resin material in the molten state is stopped. 22. A main body formed of a synthetic resin material has therein a hollow portion which is substantially concentric with the central axis and extends in the direction in which the central axis extends, and is provided at both ends of the main body with respect to the main body. First and second shaft portions having a small diameter are formed, and a through hole is formed in each of the shaft portions so as to communicate the hollow portion to the outside, and the long hole member is formed such that the through holes are substantially concentric with the central axis. A method comprising: a first shaft cavity of a molding cavity having a cavity center axis corresponding to a center axis of the long shaft member and forming a main body portion and first and second shaft portions of the long shaft member. A synthetic resin material in a molten state is injected into a resin injection portion provided on the side from a direction intersecting with the central axis, and a gas nozzle is injected from a direction parallel to the central axis by a gas nozzle to remove the synthetic resin material in the molten state. While pressing against the inner wall of the molded product cavity, the hollow part is While moving toward the second shaft cavity, the excess molten resin due to the formation of the hollow portion is guided to the excess resin receiving cavity through the second shaft cavity, and the gas in the hollow portion is maintained at a predetermined pressure. Then, the molten resin is cooled and hardened, and thereafter, the inside of the hollow portion is degassed, a molded product is taken out from the molded product cavity, and unnecessary parts of the molded product are cut to form the long shaft member. A method for forming a long shaft member, characterized by comprising: