JPS59371B2 - Rotating body manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for manufacturing a rotating body made of rubber or resin by press-fitting a curable liquid raw material of rubber or resin into a substantially closed cylindrical mold and then curing the raw material; Regarding the device.

A rotating body made of rubber or resin (...roller,
Although it includes an endless belt, it will be simply referred to as a roller for the sake of explanation.

), it is easier to manufacture and easier to mass produce than mechanical processing, and it is also possible to stably supply rollers of the same specification. The actual situation is that the law is advantageous and is widely used.
In such a molding method, liquid rubber (for example, silicone rubber, thiokol rubber, chloroprene rubber, butadiene rubber, uranium rubber, etc., materials that are liquid before curing and exhibit rubber-like elasticity after curing) or elastic epoxy. By devising the reactive molecular chains, we can create elastomers that are liquid before the reaction and harden and exhibit elasticity after the reaction, as well as Stir-V soaptadiene block polymers (SBS), thermoplastic polyurethanes, and thermoplastic polyurethanes that melt and soften when heated. Polyether-polyester block polymers, trans-1|4-polyisoprene, thermoplastic polyolefins, thermoplastic elastomers such as butyl-grafted ethylene, and even methyl methacrylate, 6-nylon, general-purpose epoxies, etc. are liquid before curing. A so-called casting resin, etc., which becomes solid after hardening, is used as a raw material and hardens in a mold to form a molded product. Conventionally, cast molding methods using this type of liquid rubber or resin include the split mold method explained based on FIGS. 1 and 2, and the split mold method explained based on FIGS. 3 and 4.
A typical example of the casting method using a seamless cylindrical mold, which will be explained based on the drawings, is well known.

FIG. 1 schematically shows a cross section of a split mold.

The roller core shaft 1 is clamped and fixed between an upper mold 2 and a lower mold 3 (of course, the core shaft 1 may be hollow and pipe-shaped). A curable liquid raw material of rubber or resin is injected from either of these sources. Thereafter, for example, if RTV type silicone rubber is used, it is allowed to solidify at room temperature. When polyatofluoroethylene is used, it is heated and melted into a liquid, which is then cooled and solidified after casting. Incidentally, 5 is a mold space corresponding to the thick part of the roll to be molded, and the dotted line L1 indicates the seam of the split molds. After casting and solidifying the liquid rubber or resin as described above, the mold is removed to obtain a resultant as shown in the second figure. In the figure,
6 is a thick portion of hardened or solidified rubber or resin. T
a,Tb,? c occurs due to the joint shape of the split mold. This is the so-called burr. Since the occurrence of such burrs is almost unavoidable in the manufacturing method using the mold shown in Figure 1, the mold space is made in advance to be X larger than the specified roller diameter and length, so that the resulting product has the specified dimensions ( Secondary stressing such as grinding is applied until the point (shown as dotted line L2) is finished. Another conventional method is explained with reference to FIG.

This method has been evaluated as a method for eliminating burrs caused by the use of split molds. In the figure, 8 is a seamless cylindrical type,
One side end 8a has an opening 10 into which a roller core shaft 9 can be inserted and fixed, and the other side end 8b has one injection port 11 left. Liquid rubber or resin is injected into the mold space 12 through the injection port 11, where it solidifies or hardens. Thereafter, the mold is demolded to obtain a resultant product as shown in the fourth figure. Incidentally, 13 is a thick portion of rubber or resin, and a wave 1 surface remains on at least one side end 13/. Therefore, it is finished by grinding to the dotted line L3 position. 9 is a roller core shaft.

According to the conventional method described above, it is extremely common for rotating bodies to have various types of defects as described below.

In other words, since the conventional method is simply a casting method, Fig. 5A, 2b
As schematically shown in the cross section of the roller shown in FIG. 1, many pinholes or voids remain in the thick portion 14 after molding. for example,
In the figure, 15 is a pinhole generated on the surface of the roller thick part 14, 16 is a bubble generated and remaining in the thick part 14, and 17 is a bubble generated near the interface between the roller core shaft 18 and the second thick part 14. , 19 are air bubbles generated and remaining on the surface of the thick portion 14, which are larger in diameter and depth than the pinhole 15. Also, a large number of bubbles, such as 20, may be generated and remain in succession. 16', 17', 20' are bubbles 5, respectively.
16, 17, and 20 show concave portions on the roller surface caused by the rollers.

The defects shown in FIGS. 5A and 5B described above frequently occur in common with the conventional manufacturing method described based on FIGS. 1 and 3 described above. The following FIG. 6 mainly explains the defects that occur frequently in the three conventional manufacturing methods described based on FIG. 3 above. On the circumferential surface of the roller thick portion 21, band-shaped recesses such as 22 and 23, which are formed in a band shape in the longitudinal direction of the roller, can be seen. 24 is a crack-shaped recess formed on the end face of the thick portion 21, and four recesses such as 24/ are left on the peripheral surface of the roller.

Incidentally, 25 is the roller core shaft. If such a defect exists in a roller, for example, when the roller is used for fusing copy materials, it may cause uneven pressure and fixing failure, or when used for the purpose of conveyance, it may cause the conveyed material to meander. This causes inconveniences such as not being able to convey accurately, causing the conveyed items to wrap around each other, and causing wrinkles. In addition, the speed of the transmission roller is not fixed, resulting in loss of reliability in use. Furthermore, as a coating roller, it has a fatal drawback in various applications, such as the inability to apply uniformly.
The present invention eliminates most of the drawbacks of such conventional methods, and provides a manufacturing device that can stably supply high-precision rotating bodies at a high yield without requiring any secondary stress such as grinding. The main purpose is to provide

In short, the present invention for achieving such an object comprises a cylindrical mold, and two side molds that are connected to both ends of the mold to substantially seal the inside of the cylindrical mold, and one of the side molds has a cylindrical mold. A rotating body, characterized in that a press-fitting means for press-fitting a curable liquid raw material into the cylindrical mold is integrally connected, and the press-fitting means is connected to the inside of the cylindrical mold via a check valve. This is the manufacturing equipment. The present invention will be specifically described below with reference to the drawings.

FIG. 7 is a sectional view schematically showing the manufacturing apparatus of the present invention. In the figure, 26 is a seamless cylindrical shape made of a rigid body such as metal, and if the liquid raw material for the roller to be obtained contracts when it hardens or solidifies, it is necessary to adjust the diameter and length of the roller to the required specified diameter and length. Use a mold whose inner diameter and length are calculated in advance to account for the shrinkage rate. Conversely, when using a liquid raw material that expands, it is common to use a mold sized to take into account the expansion rate. Furthermore, since the shape of the inner surface of the cylindrical mold somewhat controls the shape of the outer circumferential surface of the resulting roller, the inner surface 26' of the cylindrical mold 26 should preferably be mirror-finished to a surface roughness of lμ or less. 27 is a pedestal for fixing the cylindrical mold 26 and the roller core shaft 28 in a predetermined positional relationship.

Reference numeral 29 denotes an upper mold used together with the pedestal 27 to hold the cylindrical mold 26 and the roller core shaft 28 in a predetermined positional relationship.

The pedestal 27 and the upper mold 29 have core bearing parts 30 and 3, respectively.
1 is provided. Moreover, the cylindrical mold 26 and the pedestal 27 are 3
At the 2nd position, the cylindrical shape 26 and the upper die 29 can be joined at the 33rd position using screws or the like. Note that the joint portions 32 and 33 are provided with air escape portions 34 and 35, respectively. 36 is a liquid raw material 3 made of rubber or resin
7, the top lid 38 of which has an opening 39;
It leads to a conduit 40 inside the cradle 27 .

41 is a bottom plate for pushing up the liquid raw material 37 with a pressure P, and is provided with a movable sealing mechanism 42 such as an O-ring.

Incidentally, 43 is a space corresponding to the thick part of the roller to be obtained, and 44 is an opening for injecting the liquid raw material 37. In the conventional method, since the liquid raw material 37 is injected from the top of the mold at normal pressure, air bubbles are trapped in the liquid raw material at that time.
As a result, voids and pinholes are left in the cured product.

In addition, the liquid raw material itself, for example, RT-type silicone rubber, is usually applied by mixing two liquids, the main agent and the catalyst.
The curing reaction proceeds rapidly and the viscosity increases, making defoaming almost impossible even under reduced pressure. This often results in the defects mentioned above. On the other hand, in the present invention, the bottom plate 4 equipped with the movable ceiling 42
With the top lid 38 removed, a liquid raw material, for example, rubber as the main ingredient, [trade name, KE-12RTV silicone rubber; manufactured by Shin-Etsu Chemical] 10 is placed in the space 45 of the container 36 containing 10
A mixture of 0 parts by weight and 0.5 parts by weight of catalyst is used. Next, the container 36 is sealed with the upper lid 38, and the liquid raw material 37 is sealed.
After degassing, the pedestal 27 is connected to the upper lid 38.
Furthermore, after installing the core shaft 28 and the seamless cylindrical mold 26 at predetermined positions on the pedestal 27, they are fixed by being held down by the upper mold 29 under pressure P2. A base treatment is applied to the core shaft 28 as necessary to increase the adhesive force with the thick part to be molded. Note that the pressure P2 is the internal pressure when the mold space 43 is filled with the liquid raw material 37. Must be bigger.

In this example, a seamless metal cylindrical mold with an inner diameter of 30.35φ and a length of 321 mm was used. In this state, the bottom plate 41 was gradually pushed up at a pressure of about 30 k9/Cm2, and the liquid raw material 37 was press-fitted into the mold space 43 through the opening 44 via the opening 39 and the conduit 40. At this time, the escape parts 34 and 35 are designed to allow low viscosity substances such as air to pass through, but not to allow high viscosity liquids such as silicone rubber liquid raw materials to pass therethrough. In this state, when the bottom plate 41 is further pushed up, the check valve 46 operates in a state where the internal pressure of the mold space 43 and the pushing pressure P1 are balanced, and the mold space 43 remains pressurized until the internal pressure is increased until the liquid raw material hardens. is maintained. In the present invention, an appropriate push-up pressure P1 should be selected depending on the viscosity of the liquid raw material used, and according to the knowledge obtained by the present inventors, the viscosity is 1 to 1.
For liquid raw material of 50 poise, approximately 1 to 10k9/
C! For liquid raw materials with N2 pressure of 50 poise or more, it is approximately 10k9/C! By press-fitting with N2 or more and maintaining that pressure at least until hardening, it is possible to obtain a high-precision roller without pinholes or voids as described above. In other words, if the above-mentioned press-in pressure and internal pressure until curing are maintained, even if the liquid raw material is incompletely defoamed or if air is trapped in the mold, the gas and liquid will be separated. Since the viscosity relationship between gas and liquid is that only gas becomes extremely mobile, it is properly discharged through the relief parts 34 and 35 until the liquid raw material solidifies or hardens.
This is because no air bubbles are left in the thick part of the roller. Next, in this example, the press-fitting conditions were as specified above, and the product was left for two days at 25° C. and 65% relative humidity.

Thereafter, as shown in Figure 8, a required pressure P3 was applied to the core shaft 28 to remove the mold, yielding a silicone rubber roller with a roll outer diameter of 30.0 φ and a roll thickness of 320 mm. There are no discernible pinholes or holes in the thick rubber portion 47 of such a roller, and some burrs 48 remain on the end surface of the thick roller portion 47 on the pedestal 27 side; This does not affect the performance of the roller, and since the diameter of the opening 40 is specified to be smaller than the roller wall thickness, the connection between the cylindrical mold 26 and the pedestal 27 after curing is completed. When removing, threads are cut at the same time, and secondary processing of the roller end face is not required. Furthermore, in the manufacturing method of the present invention, the hardened roller is removed from the cylindrical mold 26 as shown in FIG. It is preferable to perform mold treatment.

Furthermore, apart from the previous example, when a thermoplastic resin such as polytetrafluoroethylene is used as the liquid raw material,
The same method as described above can be carried out by adding heating and cooling means to the container 36, cylindrical mold 26, etc. of the above apparatus.

As described in detail above, according to the present invention, a rotating body made of rubber or resin that fully satisfies the required performance as a rotating body for various uses can be easily manufactured without requiring any particular secondary processing. be able to.

Furthermore, the manufactured rotary body does not cause uneven contact or clogging with foreign matter during pressure welding, and is very effective. In the embodiment described above with reference to the drawings, only the method for manufacturing a roller-like rotating body is described, but the present invention is of course fully applicable to a method for manufacturing an endless belt. be.

[Brief explanation of the drawing]

1 and 3 are schematic cross-sectional views of a manufacturing apparatus shown to explain a conventional method for manufacturing a rotating body, FIG. 2 is a schematic diagram showing a rotating body obtained in the first illustrated example, and FIG. The figure is a schematic diagram showing the rotating body obtained in the third illustrated example, Figures 5A, b, and 6.
The figure is a schematic diagram illustrating defects in a rotating body obtained by the conventional method, FIG. 7 is a sectional view showing an outline of the manufacturing apparatus of the present invention, and FIG.
The figure is an explanatory diagram of a part of the usage mode of the present invention. In the figure, 26......cylindrical type, 27......
cradle, 28... core shaft, 29... upper mold, 30, 31... core bearing part, 32, 33...
...Joint part, 34, 35...Escape, 36.
...Container, 37...Liquid raw material, 38...
...Top lid, 39...Opening, 40...
... Conduit, 41 ... Bottom plate, 42 ... Movable ceiling, 43 ... Mold space, 4411 opening ~ 4611 Check valve) Pl9P2'P3 ...
pressure.

Claims (1)

[Claims] 1 Comprising a cylindrical mold and two side walls connected to both ends of the mold to substantially seal the inside of the cylindrical mold, one side of the side mold having a press-fitting means for press-fitting a curable liquid raw material into the cylindrical mold. An apparatus for manufacturing a rotating body, characterized in that the press-fitting means is connected to the inside of the cylindrical mold through a check valve.