Patent Application
20160089832
The present invention relates to a resin bonding device having a resin melting injection device for melting a plurality of plastic pellets into resin in a melting device in a heated state and injecting the molten resin and an adapter, the resin bonding device being capable of bonding a first member and a second member to each other speedily and airtightly by the molten resin injected from the resin melting injection device.
Generally, there are screw-type and plunger-type injection devices. As representative examples, a screw-type injection device is disclosed in the patent literature 1 and a plunger-type injection device is disclosed in the patent literature 2. As disclosed in these literatures, the injection device is mainly formed of a cylinder and a screw. Pellets are injected from a hopper provided in the cylinder and are conveyed to the injection nozzle side by rotation of the screw inside the cylinder, while they are heated and melted. Then, the molten resin is gathered at the tip end of the nozzle and injected so that the molten resin is conveyed to a die.
Generally, plastic pellets (hereinafter referred simply as “pellets”) are made from plastic (synthetic resin), and the heat conductivity is 0.07 to 0.20 kcal/m·hr·° C. This is one several hundredth to one several thousandth of the heat conductivity of metal. In view of this, the pellets are approximately heat insulating material. Accordingly, even if the pellets are given a sufficient amount of melting heat to be melted, the heat is hard to reach the inside of the pellets (centers of the pellets), and it takes much time to heat the pellets completely.
Therefore, it is difficult to shorten the time from when each pellet is melted sufficiently and to when resin molding is produced. The pellets need to be melted for a relatively long time in the cylinder and the working efficiency is not good. Besides, in the injection device, each solid of the pellets is heated and moved to the injection side by rotation of the screw, and at this time, a part of many pellets is pressed against the inner wall of the cylinder.
In other words, the pellets are pressed by the inner wall of the cylinder. Then, the surface of the solid of each pressed pellet is partially in contact with the inner wall of the cylinder and melting of each pellet is restricted to a part of the pellet solid in contact with the cylinder. The pellets kneaded in the cylinder by the screw are moved away from the inner wall of the cylinder for a short time and therefore, the pellets are not heated sufficiently and pellet solids are not melted as a whole, resulting in mixture of melted parts and non-melted parts of the pellets.
As the pellets are pressed against the inner wall of the cylinder by screw in a repeated manner, the pellets are completely melted, and when melted pellets are conveyed toward the nozzle, the amount of resin pooled in the cylinder is equal to or more than several tens of times of the amount that is needed for one injection so that an unnecessary amount of pellets remains in the cylinder.
Besides, when the molten resin passes through a gap between the screw and the cylinder, the resin suffers mechanical damage. Particularly, such a problem is often caused when melting pellets with glass fibers and the screw may be worn. Further, as each pellet is partially melted at random, it is inevitable that the like pellets may remain everlastingly in the cylinder. Accordingly, the operation may become particularly difficult when changing pellet materials in the cylinder.
As a substitute as such a screw type, there is a plunger-type injection device. Such a plunger type is simple in structure and is likely to be downsized. For the plunger type, it does not have the defect that the screw may be worn. The patent literature 2 discloses the plunger type injection device having the most basic structure, which is configured to have a head-cut conical shaped heating cylinder having a plurality of through holes, an injection plunger, a supply tube and so on. The injection plunger is used to convey a synthetic resin material to the heating cylinder to be injected. However, the injection device of the patent literature 2 also has various problems.
In the patent literature 2, the injection plunger and the head-cut conical shaped heating cylinder are formed to have different diameters at their facing surfaces, and the diameter of the injection plunger is formed slightly one size smaller than the diameter of the heating cylinder at the facing portion. In addition, there is formed an air space surrounded by the tip end of the injection plunger, the heating cylinder, a tip end part of the injection plunger and a supply tube, and this air space is a larger area than the area at the tip end of the injection plunger.
Accordingly, the melted synthetic resin material is once pushed into the air space by the injection plunger, but even when the injection plunger further moves toward the heating cylinder, the synthetic resin material is not able to flow into the through holes of the heating cylinder efficiently and some material may remain in the air space without flowing into the heating cylinder. Then, the residual synthetic resin material in the air space may become an obstacle to a synthetic resin material that is to be newly supplied into the through holes of the heating cylinder. And, there may arise a problem of mixture of the synthetic resin material to be newly supplied and residual resin remaining for a long time to be deteriorated.
Then, the applicant of the present application has developed an injection device in a molding machine which is capable of eliminating the inconveniences of the injection plunger and the head-cut conical shaped heating cylinder and performing the pellet resin melting step and the molten resin injection step extremely efficiently, as disclosed in the patent literature 3. According to this patent literature 3, there has been provided an epoch-making invention that only by pressing a lump of pellets by the plunger, it is possible to cause the pellets to pass through a plurality of cone-shaped holes of the melting device thereby to melt the pellets into molten resin and inject the molten resin simultaneously.
According to this invention, in the melting step of melting pellets, the pellets pass through a plurality of cone-shaped holes of a heated melting device with a predetermined pressure and when the pellets go out of the outlet, the pellet solid becomes molten resin. That is, the melting speed and the injection speed are set to be the same in consideration of the quality of pellet material, viscosity of molten resin, melting temperature, pressure, melting speed, injection speed, flow rate and so on. With this invention, melting is very accelerated in terms of the melting speed. Further, as compared with conventional injection devices, the injection device has been remarkably miniaturized successfully and other application purposes have been proposed.
In the patent literature 3, disclosed is the invention for bonding appropriate members by the injection device. This bonding device uses a conventional injection device and has a major drawback that bonding is difficult to perform smoothly due to a complicated gate part and a small hole diameter. Particularly, there are demands for use of a miniaturized resin melting injection device and successful resin bonding of at least two members with excellent airtightness, without use of rivet, bolt and nut, welding or the like.
Then, the problem to be solved by the invention (purpose of the present invention) is to provide a resin bonding device having a miniaturized resin melting injection device and an adapter, capable of successful bonding of first and second members speedily and airtightly with use of resin that is injected from the resin melting injection device.
In order to solve the above-mentioned problem, the present inventor have pursued studies diligently and reached the present invention. That is, a first aspect of the present invention is a resin bonding device comprising: a resin melting injection device having: a cylinder having an outlet member formed at a tip-end injection side in a longitudinal direction, a stopper part provided at a rear side, and a pellet supply opening provided in an intermediate position between the stopper part and the outlet member for supplying plastic pellets; a melting device having a plurality of melting holes formed communicating from inflow-side large openings to outflow-side small openings in the longitudinal direction of a device main body, the melting device having a diameter equal to an inner diameter of the cylinder; a heating unit for heating the melting device; and a drive unit for causing the melting device to move in a reciprocating manner, wherein the outflow-side small openings of the melting device face the outlet member, the melting device operates as a plunger in the cylinder, and a return travel by the drive unit is configured to correspond to a melting step of melting the plastic pellets and an outward travel by the drive unit is configured to correspond to an injection step of molten resin, in the cylinder, an opening and closing valve is provided between the outlet member and the melting device, and the opening and closing valve is configured to open the outflow-side small openings of the melting device in the melting step and to close the outflow-side small openings of the melting device in the injection step; and an adapter for applying the molten resin injected from the outlet member, to at least one side surface of a first member and a second member and preventing the molten resin from escaping to resin-bond the first member and the second member to each other.
A second aspect of the present invention is characterized in that, in the first aspect, the adapter comprises a first adapter and a second adapter, the first adapter has an insertion opening formed therein for inserting a nozzle part for injecting the molten resin generated in the resin melting injection device, and back surfaces of the first adapter and the second adapter are formed to have stopper surfaces for closing connection holes formed respectively in the first member and the second member and for preventing the molten resin from escaping.
A third aspect of the present invention is characterized in that, in the first aspect, the adapter comprises a first adapter and a second adapter, the first adapter has an insertion opening formed therein for inserting a nozzle part for injecting the molten resin generated in the resin melting injection device, and a back surface of the first adapter or the second adapter is formed to have a recess part for closing connection holes formed in the first member and the second member and for forming a bulged part of larger diameter than a diameter of the connection holes.
A fourth aspect of the present invention is characterized in that, in the first aspect, the adapter comprises a first adapter and a second adapter, the first adapter has an insertion opening formed therein for inserting a nozzle part for injecting the molten resin generated in the resin melting injection device, and back surfaces of the first adapter and the second adapter are formed to have recess parts for closing connection holes formed respectively in the first member and the second member and for forming bulged parts of larger diameter than a diameter of the connection holes.
A fifth aspect of the present invention is characterized in that, in the first aspect, the adapter is formed as a first adapter, the first adapter has an insertion opening formed therein for inserting a nozzle part for injecting the molten resin generated in the resin melting injection device and is formed to prevent the molten resin from escaping, a back surface of the first adapter is formed to have a recess part for closing a connection hole formed in the first member and for forming a bulged part of larger diameter than a diameter of the connection hole and the first member and the second member are bonded to each other by the molten resin.
A sixth aspect of the present invention is characterized in that, in the first aspect, the adapter comprises a first adapter and a second adapter, the first adapter has an insertion opening for injection of the molten resin, inner surfaces of the first adapter and the second adapter are formed to have a groove that surrounds the first member and the second member around and the groove is formed to communicate with the insertion opening.
A seventh aspect of the present invention is characterized in that, in the first or second aspect, a gate pin is provided inside the outlet member, and when the molten resin is being injected, the gate pin and a nozzle part are opened, and when injection is finished, the gate pin and the nozzle part are closed.
An eighth aspect of the present invention is characterized in that, in the seventh aspect, the gate pin is always controlled to close the nozzle part by an elastic force, a tip end of the gate pin is formed as a tapered part and a tip end inner shape of the nozzle part is formed as an injection tip end opening corresponding to the tapered part.
A ninth aspect of the present invention is characterized in that, in the first or second aspect, the adapter comprises a first adapter and a second adapter, the resin melting injection device comprises a plurality of resin melting injection devices, the first adapter or the second adapter has an insertion opening formed therein for inserting a nozzle part for injecting the molten resin generated in the resin melting injection device and a back surface of the first adapter or the second adapter is formed to have a resin connector for closing connection holes formed in the first member and the second member and to have a stopper surface for preventing the molten resin from escaping.
A tenth aspect of the present invention is a resin bonding device comprising: a resin melting injection device having: a cylinder having an outlet member formed at a tip-end injection side in a longitudinal direction, a cylindrical plunger with a stopper part provided at a rear side, and a pellet supply opening provided in an intermediate position between the plunger and the outlet member for supplying plastic pellets; a drive unit for causing the plunder to move in an axial direction in a reciprocating manner, a melting device having a plurality of melting holes formed communicating from inflow-side large openings to outflow-side small openings in the longitudinal direction of a device main body; a nozzle that is provided at an injection side of the cylinder; and a heating unit for heating the melting device, wherein the melting device is arranged between the plunger and the outlet member, and the plastic pellets supplied from the pellet supply opening flow into the inflow-side large openings by pressure of the plunger and flow out from the outflow-side small openings as molten resin; and an adapter for applying the molten resin injected from the outlet member, to at least one side surface of a first member and a second member and preventing the molten resin from escaping to resin-bond the first member and the second member to each other.
According to the present invention, a resin melting injection device for melting a plurality of plastic pellets into resin in a heated melting device and injecting the melted resin and an adapter are used to bond a first member and a second member to each other with molten resin injected from the resin melting injection device, which brings about a great advantage of enabling speedy, airtight and waterproof bonding.
Particularly, in an experimental example, when many pellets are stacked in the cylinder, pressure is applied and thereby, the pellets filled up in the cylinder do not flow back, but are pressed by each other to pass through a plurality of melting holes communicating from inflow-side large openings to outflow-side small openings. With this process, the pellets are melted to be molten resin effectively.
The pressed multiple pellets are able to be conveyed directly and with almost no wastes, to a plurality of inflow-side large openings of the melting holes of the melting device. Accordingly, multiple pellets between the fixed or movable stopper part and the inflow-side surface part of the melting device are able to be conveyed continuously. The pellets pressed between the stopper @art and the inflow-side surface part of the melting device and inserted via the inflow-side large openings of the melting holes are surrounded by the inner circumferential wall surfaces of the melting holes. Since the melting holes are each formed like a cone-shaped channel or a channel with a narrowed end, the pressing force becomes larger as the pellets move toward the outflow-side small openings, and the pellets are heated and melted to be small.
The melting device itself is heated at the melting temperature of the pellets by the heating unit so that pellets become melted. At this time, the whole circumference of each pellet is surrounded by the inner circumferential wall surface of the melting hole and the pellet is able to be melted in balance and approximately evenly from the outer circumferential part to the center. Besides, in the process where each pellet moves from the inflow-side large opening to the outflow-side small opening, as the device main body has large heat capacity, once the device main body is heated to the high temperature, the melting device heats the pellets and keeps the sufficient melting temperature irrespective of the temperatures of melted pellets.
Then, each pellet is melted approximately evenly from the outer circumference to the center, pressed by following pellets that are continuously inserted via the inflow-side large opening and thereby, is able to move toward the outflow-side small opening of the melting hole. During this movement, the pellet continues to be melted, when the pellet passes through the approximately middle portion of the melting hole in the axial direction (longitudinal direction), the pellet is almost melted, and also with the melting heat of the melting device, surrounding pellets continue to be melted in an accelerated manner. Near the outflow-side small openings, the pellets are completely melted at the highest temperature and are polled in the cylinder as molten resin.
Thus, according to the present invention, the melting device has melting holes each with a narrowed tip end in the device main body. As the multiple pellets pressed from the pellet storage area of the cylinder are inserted into the inflow-side large openings at the large opening side of the many melting holes with narrowed tip ends heated at the melting temperature by the heating unit, the pellets are melted in balance and as the melting device has large heat capacity, it is able to be kept at the high temperature. With this structure, the melting is accelerated with higher melting speed and the molten resin is pooled at the outlet member side.
Particularly, in the melting device, the temperature of resin is maximized at the outflow-side small openings by the heating unit. As the temperature of resin is optimized and maximized just before injection, it is possible to minimize the time duration where the resin is in the high-temperature state and also possible to prevent the resin from being deteriorated, thereby resulting in molding of high quality. That is, the melting device is configured to be able to increase the temperature of the resin to be optimal in the last stage of resin melting and just before injection.
Until the resin is injected into the adapter, the melting device is once heated to the high temperature by the heating unit and the high temperature is kept by the large heat capacity. Then, the melted pellets are also kept at sufficiently high melting temperatures without being decreased in temperature, thereby resulting in production of molten resin from pellets of excellent quality. When the molten resin is injected into the adapter, the resin is immediately solidified by circumferential walls or the like of the first and second members at ordinary temperatures thereby to be able to bond the first and second members to each other speedily and airtightly. Such solidification speed is different from that of a bond or joint member.
According to the second aspect, if the connection holes are formed respectively in the first and second members, the resin bonding is able to be completed instantaneously by the operation of injecting molten resin into the connection holes via the adapter. In the case of hard synthetic resin, bonding can be strengthened. Further, the adapter is implemented with a simple structure, thereby enabling inexpensive manufacturing.
According to the third aspect, if the connection hole of the first member or the second member is formed as a female screw, the present invention is able to be implemented as a resin bolt bonding structure advantageously.
According to the fourth aspect, as the connection holes are formed respectively in the first and second members and the recess parts are provided for forming bulges parts of larger diameter than the diameter of the connection holes, it is possible to perform rivet-like bonding simply and speedily.
According to the fifth aspect, particularly, if the second adapter is omitted and the connection hole of the second member is formed as a female screw, the present invention is able to be implemented as a resin bolt bonding structure. Besides, if a metal bolt of the second member is installed, the present invention is able to be implemented as a resin nut (hexagon cap nut) bonding structure.
According to the sixth aspect, if any connection hole is not provided in the first and second members, it is possible to bond the first and second member to each other. Even when the first and second members are bonded with a given space therebetween, it is possible to achieve favorable bonding. Bonding is, of course, possible when the first and second members are plate materials, and bonding is also possible even when the first and second members are round bars or square bars.
According to the seventh aspect, as the gate pin structure is used, it is possible to define the boundary between the nozzle part and the injected molten resin clearly, which brings about the effect of enabling resin bonding in an orderly manner. The same effect is also achieved in the eighth aspect.
According to the ninth aspect, particularly when the plural resin melting injection devices are arranged, they are able to be used as a plurality of hot runners with a corresponding number of nozzle parts, which produces a merit of enabling large-scaled resin bonding simply and speedily. That is, the resin connectors or the like are able to be configured in the front and back surfaces of the first and second members. According to the tenth aspect, when the melting device is of fixed type, the pellets melt, while, molten resin is injected from the tip end of the outlet member. With this structure, it is possible to perform melting and injection almost together.
With reference to the drawings, embodiments of the present invention will be described below. As illustrated in
Materials of the first member 91 and the second member 92 may be metal, glass, resin, timber or the like, and generally, they are often metal. The material of the first member 91 and the material of the second member 92 are often the same, but may be different depending on the use application. That is, they are aluminum and iron, iron and plastic, or the like.
Since the resin bonding device according to the present invention has high injection performance, there is a wide variety of available materials from low-temperature melting resin (general-purpose plastic, ABS, polyethylene, polypropylene and so on) to high-temperature melting resin (engineering plastic, polyamide, polycarbonate, polyimide and so on) and various materials are selectable depending on the use application. Colors are also selectable appropriately depending on the product.
The resin melting injection device according to the first embodiment has a movable stopper 6, as illustrated in
As illustrated in
As illustrated in
At the end of the cylinder 1 (lower end in figures) of the resin melting injection device A, the outlet member 5 is provided, and inside the outlet member 5, there are provided a stopper part 6 and the melting device 2 moving in a reciprocating manner. The inside of the stopper part 6 is formed like a cylinder, and at the tip end (lower end in figures), a plate-shaped stopper surface 61 is provided to be slidable on the inner surface of the cylinder 1 so as to provide a sealing state. The drive unit 3 of the melting device 2 is provided with a reciprocating motion bar 34. All over the stopper surface 61, there may be provided a heat insulating material 61a made of synthetic resin.
In other words, the outlet member 5 is mounted on the one-end side (lower end in
As for a material of the cylinder 1, it needs to be heated quickly and is preferably iron or stainless steel containing iron in large amounts. The cylinder 1 is configured to have a cylinder main body 11 that is formed in an elongated shape, and a tubular supply tube 12 that is connected from a pellet supply opening 11a formed near the stopper part 6.
The supply tube 12 is formed to communicate with a hopper 18 where pellets p, p are stored. The supply tube 12 is connected to the hopper via a part that is formed integral with the cylinder 1 and a pipe appropriately formed in an arc shape. The cylinder main body 11 is a cylindrical member and has an approximately column-shaped space surrounded by an inner-circumferential side surface part 11b.
The thickness of the cylinder main body 11 is preferably about 2 mm. The hopper 18 is able to store a large number of pellets p, p and the charged pellets p, p are conveyed via the supply tube 12 and the pellet supply opening 11a to the cylinder main body 11.
Though it is not illustrated specifically, the pellets p, p may be press-charged to the supply tube 12 by a screw or an air pressure device. The cross section of the cylinder 1 is a circle, but may be a distorted circle or ellipse. In such a case, accurate reciprocating movement is possible without rotating the melting device 2 of the same shape.
At one end side (lower end) in the axial direction (longitudinal direction) of the cylinder main body 11, the outlet member 5 is mounted. The outlet member 5 is configured with a nozzle part 51, a funnel part 52 and a connecting part 53. The nozzle part 51 is formed of an injection outlet end 51a and a base part 51b (see
The injection outlet end 51a is formed narrow with a small diameter, and the base part 51b is formed with a larger diameter with a step provided between the injection outlet end 51a and the base part 51b. In the first adapter 81 of the adapter 8, an insertion hole 81a is formed to have the nozzle part 51 fit therein. The connecting part 53 of the outlet member 5 is formed to have a screw structure (outer screw, inner screw) thereby to be detachable from the cylinder main body 11. The material of the nozzle part 51 preferably has excellent heat conductivity and is desired to be, specifically, beryllium copper or copper.
The melting device 2 has an approximately cylindrical device main body 21 in which a large number of melting holes 22, 22 are formed (see
As illustrated in
An outer circumferential side surface of the device main body 21 is called circumferential side surface 21c. As described above, the device main body 21 is an accurate cylindrical shape such that the diameter D2a of the inflow-side surface part 21a is equal to the diameter D2b of the outflow-side surface part 21b at any position in the axial direction of the circumferential side surface 21c (see
That is, the following equation is satisfied (see
D2a=D2b
Next, the melting holes 22 are formed in the axial direction (longitudinal direction) of the device main body 21 (see
In the present invention, the cone shape of each melting hole 22 is preferably a circular cone and the diameter of the melting hole 22 is formed to be gradually smaller (see
Besides, the small opening side of each melting hole 22 is called outflow-side small opening 22b (see
Then, the inflow-side large opening 22a is located at the inflow-side surface part 21a of the device main body and faces (is opposite to) the stopper part 6 (see
As described above, inflow-side large openings 22a, 22a of a large number of melting holes 22, 22 are arranged in the inflow-side surface part 21a of the melting device 2. In the inflow-side surface part 21a, as it faces the stopper part 6 and the pellets p, p flow into the inflow-side large openings 22a, the inflow-side surface part 21a is called inflow side of the melting device 2.
In addition, as illustrated in
When each melting hole 22 is a cone-shaped hole, the cross sectional shape orthogonal to the axial direction (longitudinal direction) is a round shape at any position (see
Each outflow-side small opening 22b has such a diameter that molten resin q obtained by melting the pellets p, p into liquid can flow, which diameter is about 1 to 1.5 mm. The melting hole 22 has a cross section along the axial direction (longitudinal direction) that is in an approximately tapered shape. That is, it is a cone shape along the axial direction (longitudinal direction), and if it is in a pyramid shape, the shape may be quadrangular pyramid or triangular pyramid. Or, a combined shape of the quadrangular pyramid and triangular pyramid may be used as well. The melting holes 22 of this type are such that the inflow-side large openings 22a of the cone-shaped melting holes 22 are formed in a polygonal shape more than triangular shape and the outflow-side small openings 22b are in a round shape.
In
The drive unit 3 is formed of a motor drive part 31 equipped with a reducer, pinion gear 32 and a rack shaft 33. Or, though it is not shown, it may be a drive unit 3 for moving a rod in a reciprocating manner by driving of a motor drive part 31 equipped with a reducer and a ball screw and ball screw nut driving. An end of the rack shaft 33 or the rod end is connected to a reciprocating motion bar 34.
As illustrated in
The motor drive part 31 is formed of a brushless motor, stepping motor or the like and is able to perform drive control with high accuracy and to control the time of the melting step and the time of the injection step of molten resin q separately in consideration of the material of pellets. Consequently, it is possible to assure sufficient time for resin melting and complete the injection step of its molten resin q efficiently and extremely rapidly and for a short time.
For example, by setting the time of the melting step to about 30 to 60 seconds and the time of the injection step of molten resin to about 1 second, there is produced an advantageous effect of being able to complete the injection and resin bonding process efficiently and extremely quickly and for a short time. Particularly, use of the brushless motor is preferable for setting the time of the melting step to be longer and controlling the time of resin bonding repeatedly and accurately.
The heating unit 4 is a member for heating the melting device 2 from the outer surface of the cylinder main body 11. The heating unit 4 is formed into a tubular shape to exhibit excellent heat conductivity to the melting device 2. Specifically, the heating unit 4 may be an IH heater in a wound shape to exhibit a sufficient amount of heat.
The heating unit 4 serves to heat the melting device 2 that moves in a reciprocating manner inside the cylinder main body 11 inside the cylinder 1. Specifically, the heating unit 4 is preferably an electromagnetic induction, that is, IH (induction heating) coil, and the heating unit 4 is formed by winding IH coil around a resin or ceramic heat insulating coil bobbin.
The shape of the bobbin is configured such that the distance between the IH coil and the outer side surface of the cylinder main body 11 becomes optimal. Input power is preferably variable from 0 to 1 Kw by a controller. The cylinder 1 is equipped with a thermocouple so that the temperature of the cylinder 1 is able to be set to an appropriate value. As another type of the heating unit 4, a band heater may be used. The heating unit 4 is not limited to the unit described above and may be any heating unit as far as it is able to be used in the present invention.
The heating unit 4 is fixedly mounted on the cylinder main body 11 and is configured to hold the heat source sufficiently in terms of the heat amount of the melting device 2 even if it moves in a reciprocating manner by drive unit 3. This is because, the heating unit 4 is generally set at the position shown in
Further, the melting device 2 is provided with a heat insulation process according to need, which is described specifically below. The reciprocating motion bar 34 of the drive unit 3 is inserted movably in a center through hole 21d that passes through the centers of the outflow-side surface part 21b and the inflow-side surface part 21a of the melting device 2. That is, the inner diameter of the center through hole 21d is formed to be slightly larger than the diameter of the reciprocating motion bar 34 and not in contact with the reciprocating motion bar 34. Further, at the center positions of the outflow-side surface part 21b and the inflow-side surface part 21a of the melting device 2, recesses parts 21a1 and 21b1 are formed.
In the recesses parts 21a1 and 21b1, there are arranged circular plate shaped support pieces 25, 25 made of a ceramics or polyimide heat insulating material. The support pieces 25, 25 are fixed to the reciprocating motion bar 34. Specifically, first, one of the support pieces 25, 25 is inserted onto the reciprocating motion bar 34, and then, the tip end side of the reciprocating motion bar 34 passes through the center through hole 21d of the melting device 2. Then, the one support piece 25 is arranged in the recess part 21a1 of the inflow-side surface part 21a of the melting device 2.
In this state, the other support piece 25 and a circular plate 71 are fit onto a collar member 72, which is then fit on a tip-end side small-diameter part 34a of the reciprocating motion bar 34. The collar member 72 is made from iron, stainless steel or the like. Besides, a nut 34c is fit on a screw part 34b of the tip-end side small-diameter part 34a of the reciprocating motion bar 34 thereby to fix the melting member 2 to the reciprocating motion bar 34. That is, the melting device 2 is fixed to the reciprocating motion bar 34 via the support pieces 25, 25 out of direct contact with the reciprocating motion bar 34. Therefore, the reciprocating motion bar 34 is able to be in such a heat insulation state that it receives almost no heat from the melting device 2.
With this configuration, the heat source generated in the melting device is configured not to be transferred to the reciprocating motion bar 34 made of metal (mainly, stainless steel) inside the cylinder 1. Thus, heat insulation of the melting device 2 is achieved for the purpose of using heat of the melting device 2 only for melting of the pellets p, p in melting. Accordingly, the heat insulating member (support pieces 25 or cylindrical collar 35) is provided between the melting device 2 and the reciprocating motion bar 34.
In particular, when the diameter of each outflow-side small opening 22b Of the melting device 2 is much smaller than the diameter of the inflow-side large opening 22a (see
As the internal configuration of the melting device 2, an opening and closing valve 7 is provided where necessary (see
Specifically, the opening and closing valve 7 is configured to close the tip end of the melting device in the outward step, or release (open) it in the return travel. More specifically, the opening and closing valve 7 is formed of a circular plate 71 and the collar member 72 with a collar 73. The collar member 72 with collar 73 is located in front of the outflow side surface part 21b of the melting device 2 and the opening and closing valve 7 is provided at the tip end of the reciprocating motion bar 34 to be slightly movable between the collar 73 and the outflow-side surface part 21b, via the collar member 72.
The diameter D7 of the circular plate 71 is formed to be smaller than the diameter D2b of the outflow-side surface part 21b (see
D7<D2b(=D2a)
This is because in the return step, the molten resin q is able to flow more easily than on the outer circumferential part of the opening and closing valve 7.
The above-mentioned structure is explained simply below. The opening and closing valve 7 is provided between the outlet member 5 and the melting device 2 and the opening and closing valve 7 is configured to have a circular plate 71 moving close to or away from the outflow-side small opening 22b of the melting device 2. The circular plate 71 is formed to have a smaller diameter than the diameter of the melting device 2.
In the circular plate 71 in the opening and closing valve 7, a plurality of through holes 71a is formed as illustrated in
In another embodiment of the opening and closing valve 7, as illustrated in
In the injection step, when the melting device 2 equipped with the opening and closing valve 7 charges molten resin q into the die, particularly, the molten resin q inside the outlet member 5 becomes under high pressure and may flow backward. Therefore, the opening and closing valve 7 is configured to be always under elastic pressure by an elastic member 75 as compression spring.
In another embodiment of the circular plate 71 of the opening and closing valve 7, though it is not shown, the circular plate 71 may be configured such that it is configured to have the same diameter as the diameter D2b of the outflow-side surface part 21b of the melting device 2 and notches are formed at plural points (for example, four points) on the circumferential edge of the circular plate 71. Each notch is formed in a U shape or horizontal U shape.
In the collar member 72 illustrated in
With the thus-configured collar member 72 and opening and closing valve 7, the circular plate 71 is configured to be able to move close and away between the collar 73 of the collar part 72 and the melting device 2. Specifically, assuming the thickness of the circular plate 71 is t, the distance between the collar and the surface of the melting device becomes thickness t+a, and the above-mentioned movement of the circular plate 71 is enabled within the range of a (see
Next description is made about the pellet melting step and theory. First, before the melting step, as illustrated in
Then, when the melting step is set ON, the return step starts by the drive unit 3 and many pellets p, p in the pellet storage area W are compressed between the inflow-side surface part 21a of the melting device 2 and the stopper part 6, as illustrated in
In general, the size of each inflow-side large opening 22a is such that a pellet p of average size is wholly inserted into the inflow-side large opening 22a (see
Accordingly, the pellets p inserted from the inflow-side large openings 22a move from the inflow-side large openings 22a toward the outflow-side small openings 22b, while each pellet p melts toward its center (see
Then, as the pellet p moves in the melting hole 22 toward the outflow-side small opening 22b, the pellet p is melted and its size is decreased gradually (see
In other words, each pellet p is surrounded approximately evenly by the inner circumferential wall part of the melting hole 22 and is always kept close to or in contact with the inner circumferential surface part (see
Further, as illustrated in
Further, as illustrated in
Thus, as the pellets p moves from the inflow-side large openings 22a of the melting holes 22 toward the outflow-side small openings 22b, melting of the pellets is advanced, melting is completed near the outflow-side small openings 22b or just before the outflow-side small openings 22b, and the pellets are liquefied (see
As described above, in the return step started by the drive unit 3, there occurs pressure f, f between the pellets p, p in the pellet storage area W, the pellets p, p are compressed, and each pellet p inserted from the inflow-side large opening 22a of the melting hole 22 is always surrounded by the inner circumferential wall surface of the melting hole 22 while it is moving toward the outflow-side small opening 22b. Therefore, the pellets p are melted by the heating unit 4, and as illustrated in
As the plural pellets p, p are able to be melted only in almost required amount, the materials are prevented from being exposed to long-time, heat and mechanical stress in the cylinder main body 11. Accordingly, it is possible to produce resin products of high quality. In addition, the injection device of the present invention is high in melting efficiency and there is no need to charge the materials excessively, thereby achieving downsizing of the device and power saving and resource saving. Further, as the temperature becomes an injection optimum temperature and highest temperature at the melting final step just before the injection, it is possible to minimize the time duration of resin at high temperatures and thereby to produce resin molding of good quality.
In the above-described structure, the melting device 2 is of the movable type and the stopper part 6 is of the fixed type. However, the melting device 2 may be of the fixed type and the stopper part 6 may be of the movable type. In this embodiment, as illustrated in
By these pressure stopper surface 63a, outer peripheral surface part 63b and rear side end part 63c, the movable cylinder 63 is formed into a cylindrical shape. The movable cylinder 63 is configured not to rotate in its circumferential direction and is also configured to move in a reciprocating manner in the axial direction (longitudinal direction) by rotation of the outer screw shaft 36 (see
As described above, the movable cylinder 63 is configured only to move in the axial direction (longitudinal direction) in the cylinder main body 11 while being prevented from rotating in its circumferential direction (see
The rear side end part 63c of the movable cylinder 63 has a through hole, in which an inner screw part is formed. The inner screw part fits with the outer screw shaft 36 of the drive unit 3 and by rotation of the outer screw shaft 36, the pressure stopper surface 63a and the movable cylinder 63 move in a reciprocating manner in the axial direction (longitudinal direction) inside the cylinder main body 11. The material of the movable cylinder 63 is iron or stainless steel, but is not limited to these. The material of the movable cylinder 63 may be any material as far as it meets the requirements for heat resistance and durability.
By movement of the movable cylinder 63 toward the melting device 2, the pellets p, p are pressed into the melting holes 22 via the inflow-side large openings 22a formed in the inflow-side surface part 2a of the melting device 2 (see
Particularly, when the melting device 2 is of the fixed type, the pellets p, p are being melted, while molten resin is injected from the tip end of the outlet member 5. With this process, it is advantageously possible to complete resin bonding (described later) instantaneously. With this melting device 2 of the fixed type, generation of molten resin coincides with injection of molten resin. Therefore, rotation of the outer screw shaft 36 of the drive unit 3 is controlled in accordance with the amount of bonded resin and the feed amounts of the first member 91 and second member 92 that are resin-bonded together are controlled thereby to enable mass production.
In the above description, the plural pellets p are supplied continuously from the pellet supply opening 11a, however, a predetermined amount of pellets p may be supplied, as illustrated in
A lower end part of the shutter plate 16a is inserted into a groove part 12a formed at the bottom of the supply tube 12 to block the pellet supply opening 11a so that flow of the plural pellets p flowing into the supply tube 12 can be shut down. When using such a shutter mechanism 16, the flow rate and the flowing time of the pellets p are considered to control the time to open or close the shutter plate 16a. With this structure, it is possible to control the amount of pellets p to be supplied from the hopper 18 appropriately.
As described above, as the pellets are melted in desired melting amounts and injected, there is an advantageous effect of being able to process them in a well-ordered manner. The stopper part 6 of the configuration illustrated in
Next description is made about the structure of the adapter 8. The adapter 8 is fundamentally configured to have a first adapter 81 and a second adapter 82. The first embodiment of the adapter 8 is formed of the first adapter 81 and the second adapter 82 as illustrated in
In back surfaces of the first adapter 81 and the second adapter 82, there are formed stopper surfaces 81b, 82b for closing connection holes 911 and 921 formed in the first member 91 and the second member 92 to be resin-bonded to each other, respectively, and for preventing the molten resin q from escaping. Specifically, when the upper and lower surfaces of the first member 91 and the second member 92 are flat surfaces, the stopper surfaces 81b, 82b are merely formed as flat surfaces.
In the case of the adapter 8 according to the first embodiment, the back surface (bottom surface) of the first adapter 81 and the back surface (upper surface) of the second adapter 82 are only formed as the flat stopper surfaces 81b, 82b, the connection holes 911 and 921 formed in the first member 91 and in the second member 92, respectively, are provided with enlarged holes 911a, 921a and tapered holes 911b, 921b for preventing detachment.
The embodiment of
As illustrated in
In the case of the modification to the adapter 8 according to the first embodiment, as illustrated in
When the first member 91 and the second member 92 are thus resin-bonded, and then, if the first member 91 and the second member 92 are to be separated temporarily, the resin hardened in resin bonding may be used as a headless screw. If the first member 91 and the second member 92 are finally to be disassembled, as the molten resin q is used, the resin is heated above the melting temperature of the resin so that the bonding is destroyed thereby to make the first member 91 and the second member 92 disassembled easily.
The adapter 8 according to the second embodiment is comprised of the first adapter 81 and the second adapter 82, as illustrated in
In the second adapter 82, a flat surface for closing the connection hole 921 as the screw hole formed in the second member 92, and it is formed as the stopper surface 82b as the surface for preventing the molten resin q from escaping. In this case, the first member 91 and the second member 92 are bonded to each other by a resin bolt. If disassembling is requested, it is advantageously possible to disassemble the first member 91 and the second member 92 by loosening the resin bolt, which is hardened in resin bonding, and also possible to return them into an original state.
In a modification to the adapter 8 according to the second embodiment, as illustrated in
In the second adapter 82, there is formed a recess part 82e for closing the connecting hole 921 formed in the second member 92 and for forming a bulged part 82e that corresponds to a bolt head of larger diameter than the diameter of the connecting hole 921. The flat surface excluding the recess part 82e is formed as the stopper surface 82b for preventing the molten resin q from escaping. Also in this case, the first member 91 and the second member 92 are bonded to each other by a resin bolt. If disassembling is requested, it is advantageously possible to disassemble the first member 91 and the second member 92 by loosening the resin bolt, which is hardened in resin bonding, and also possible to return them into an original state.
The adapter 8 according to the third embodiment is comprised of the first adapter 81 and the second adapter 82, as illustrated in
Specifically, in the embodiment, the connecting holes 911, 921 formed, respectively, in the first member 91 and the second member 92 for resin bonding are closed, while bulged resin parts Q1 are formed at the upper and lower ends of the overlapping connecting holes 911, 921. The molten resin q functions as a rivet as a whole thereby to allow bonding (adhesion). According to the present invention, as far as the first member 91 and the second member 92 are prepared, it is possible to resin-bond the first member 91 and the second member 92 instantaneously and with high airtightness and high water-tightness.
In addition, in a modification to the third embodiment, as illustrated in
The bolt head of the resin bolt may be hexagonal head, square head or bolt head that fits to the hexagonal wrench. Or, the metal nut 67 also may be of any shape such as square or octagonal. Also in this embodiment, if disassembling of the first member 91 and the second member 92 is desired, it is advantageously possible to disassembly the first member 91 and the second member 92 by loosening the resin bolt, which is hardened in resin bonding. As the metal nut 67 is used, it is possible to allow strong bonding and also possible to return them into an original state. If the metal nut 67 is not welded, there is a merit of facilitating disassembling as a whole.
According to the fourth embodiment, the adapter 8 is comprised only of the first adapter 81, as illustrated in
At that time, in the second member 92, there is formed a hole part 92d as a screw hole. When high strength is required, the hole part needs to be formed relatively deeper. With this structure, it is possible to eliminate the need to provide the second adapter 82. The connecting hole 911 of the first member 91 is formed as a simple hole. In the embodiment of this type, only one adapter is used thereby to achieve cost saving.
In a modification to the fourth embodiment, as illustrated in
The resin hexagon cap nut may be any shape, such as hexagon, square or shape that fits to the hexagonal wrench. Or, the metal bolt 68 also may be of any shape such as square or octagonal. Also in this embodiment, if disassembling of the first member 91 and the second member 92 is desired, it is advantageously possible to disassembly the first member 91 and the second member 92 by loosening the resin hexagon cap nut, which is hardened in resin bonding. Particularly, as the metal bolt 68 is used, it is possible to allow strong bonding and also possible to return them into an original state. If the metal bolt 68 is not welded, there is a merit of facilitating disassembling as a whole.
In the case of
The adapter 8 according to the fifth embodiment is comprised of the first adapter 81 and the second adapter 82, as illustrated in
Particularly, in the inner surface of the second adapter 82, there is also formed a groove 82n that extends to surround the first member 91 and the second member 92 around. The groove 82n is configured to communicate with the groove 81n of the first adapter 81. With this structure, it is possible to bond the first member 91 and the second member 92 to each other even if there is no hole and no notch. Besides, if disassembling is desired, it is possible to disassembly the first member 91 and the second member 92 by heating them above the melting temperature of the resin-bonded molten resin q and melting the resin. That is, it is possible to return the first member 91 and the second member 92 in to an original state.
In a modification to the fifth embodiment, as illustrated in
Further, as illustrated in
In the sixth embodiment, as illustrated in
In a second adapter 82, a recess part 82e is formed for closing the connection holes 921 formed in the second member 92 and also for forming a bulged part corresponding to a bolt head of larger diameter than the diameter of the connection hole 921. The flat surface excluding the recess part 82e is formed as the stopper surface 82b for preventing the molten resin q from escaping. Also in this case, the first member 91 and the second member 92 are bonded to each other by a resin bolt. Particularly, the second adapter 82 is formed to have a large width.
A third adapter 83 is provided on the first member 91 slightly apart from the first adapter 81. That is, as illustrated in the right side of
The flat surface excluding the recess part 83c is formed as a stopper surface 83b for preventing the molten resin q from escaping. In the third adapter 83, the flat surface is formed only for closing the connection hole 921 as a screw hole formed in the second member 92, which surface is also formed as the stopper surface 82b for preventing the molten resin q from escaping. In this case, the first member 91 and the second member 92 are bonded to each other by resin bolts.
In the seventh embodiment, as illustrated in
In the first member 91 and second member 92 like thin plates, sheets or the like, connection holes 912, 921 are formed as long holes at three parts between the two plates. That is, three holes are formed within the widths of the recess parts 81s, 82s. In addition, in the first adapter 81, two insertion openings 81a are formed each for inserting the nozzle part 51 for injecting the molten resin q generated in the resin melting injection device A. The product is manufactured as illustrated in
Particularly, when the resin connectors q81, q82 are wide and large sized, temperature control is required. Therefore, as illustrated in
As illustrated in
Further, between the upper end (rear end) of the gate pin 55 and the upper end of the accommodating part 56a, a compression spring is provided to always urge the gate pin 55 downward elastically. The inner diameter of an injection tip end opening 51a1 of the injection opening 51a of the nozzle part 51 is formed to fit in the same plane with the tapered part 55a of the gate pin 55 with no gap provided therebetween. And, a most part of the tapered part 55a is configured to be located within the injection opening 51a.
Next description is made about the operation state of the gate pin opening mechanism. In such a structure, when the outlet member 5 part is fully charged with molten resin q under pressure, the pressed molten resin q is moved all around the tapered part 55a of the gate pin 55. Then, as illustrated in
When injection is finished, the pressure on the molten resin q becomes lost and the gate pin 55 is elastically urged downward by the compression spring 57 thereby to close the injection tip end opening 51a1. As this gate pin opening mechanism is provided, the resin hardened by resin bonding and molten resin q within the outlet member 5 part are separated excellently thereby to accomplish resin bonding in an orderly manner.
In the embodiment as illustrated in
The first adapter 81, the second adapter 82 and the third adapter 83 thus described up to this point are all flat plate-shaped adapters, which shape fits the first member 91 and the second member 92. However, the adapter shape is not limited to a flat plate and may be any of various shapes that can fit the right angle, corner, curved plate, square bar, round bar, sheet and so on.
Further, the material of the first adapter 81 and the second adapter 82 may be metal, glass, resin, timber or the like, but it is often metal. The material of the first adapter 81 and the material of the second adapter 82 are often the same, but may be different depending on the use application or the material of the first member 91 and the second member 92, and for example, they may be aluminum and iron, iron and plastic, or the like.
Regarding the device for installing the resin melting injection device A, as explained with reference to
The present invention enables an extremely wide variety of resin bonding of two or more members and exhibits extremely high industrial applicability in various manufacturing industry.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-123256 | Jun 2013 | JP | national |
This application is a continuation application of International Patent Application No. PCT/JP2014/065298 filed on Jun. 10, 2014, which claims priority to Japanese Patent Application No. 2013-123256 filed on Jun. 11, 2013, the entire contents of which are incorporated by reference in their entirety herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2014/065298 | Jun 2014 | US |
| Child | 14964692 | US |
