JPH0136593Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a rotary joint that connects an extruder and a die.

Conventionally, a rotary joint as shown in FIG. 1 has been proposed as this type of joint. This rotary joint a is the first
As shown in the figure, it consists of an inlet side main body b and an outlet side main body c, and the upper part of the resin passage d provided inside the inlet side main body b is connected to an extruder (not shown), and the lower part is also not shown in the figure. The lower end is closed with a screw plug e. f and g are seals and bearings, which are interposed between the outlet side body c and the inlet side body b, and their flange portions are connected to the step end face of the inlet side body b, the end face of the outlet side body c, and the outlet side body They are each held between the end face of c and washer h. This washer h is fitted into the screw plug e, and the nut i
The bearing g is tightened by a disc spring l fixed in such a manner that the amount of deflection can be freely adjusted with a washer k, and the tightening force is used to connect the bearing g to the outlet side main body c, and the outlet side main body c to the bearing f. f is brought into close contact with the main body b on the inlet side. As mentioned above, the required sealing performance of the sealing surface of the seal/bearing f, g interposed between the outlet side main body c and the inlet side main body b of this rotary joint a is determined by the resin pressure in the resin passage d. to be influenced.

That is, when the resin pressure becomes higher than the set pressure, the sealing performance provided by the amount of deflection of the disc spring 1 is reduced, and there is a risk that resin leakage may occur.

When this resin leakage occurs, it is necessary to tighten and adjust the nut i each time, which poses problems in operability and productivity.

In addition, instead of this operation, if you take the maximum resin pressure into account and tighten it strongly from the beginning, a large rotational force is required to rotate the outlet side main body c, which may cause problems such as inability to rotate or galling on the sealing surface. occurs.

This invention solves these problems,
An inlet body has a resin passage connected to the extruder at one end, and a communication hole provided at the other end of the resin passage opens toward the die, and the body is fitted onto the outside of the inlet body through a seal and bearing member. a rotatable outlet body, a through hole that connects the outlet body to a communication hole in the inlet body, and a pressing member that presses the seal/bearing member in the axial direction through an elastic member to seal the body. In the rotary joint, the seal/bearing member is a bush divided in the axial direction of the resin passage, an elastic member is installed between the outlet side main body and the bush, and the opposing outer peripheral walls of both bushes are provided. The present invention relates to a rotary joint characterized in that a thin wall portion is formed on the rotary joint.

The present invention will be described below with reference to illustrated embodiments.

In Figures 2 to 4, reference numeral 1 denotes an inlet side main body, which has an inverted L-shaped resin passage 2 inside, and an inlet side opening of the passage is connected to an extruder (not shown) via a connecting pipe 4. There is. A large number of communication holes 6 are bored radially in multiple stages in the side wall on the exit side of the passage 2. 7 and 8 are two-part bushings that serve as seals and bearing members; main body 1 on the inlet side;
It is rotatably and slidably fitted around the outer periphery of the The bushes 7 and 8 are made of a non-lubricated bearing material such as heat-resistant resin or other oil-less bearings having the same effect, and have a lapping shape on the mutually opposing outer circumferential walls that gradually decreases in thickness toward the outside. A thin wall portion 9 is formed and a flange portion 10 is provided. When the resin pressure in the resin passage 2 increases, a thrust force in the direction of arrow A is applied to the bushes 7 and 8 due to the resin pressure, as shown in FIG. 4, but this thrust force changes in proportion to the resin pressure. The thin portion 9 is expanded outward by the resin pressure and comes into contact with the inner periphery of the outlet side main body 3 to form a sealing surface B (see FIG. 4) on the outer periphery of the bushes 7 and 8.

Reference numeral 3 denotes an exit side main body, in which an elastic member such as a disc spring 12 is installed between the concave portions 11 at both ends and the flanges 10 of the bushes 7 and 8, and pins 13 fixed at both ends are attached to the flanges 10 of the bushes 7 and 8. Hole 1 formed in
3, so that it can slide in the axial direction with respect to the bushes 7, 8, and can rotate integrally with the bushes 7, 8 with respect to the inlet side main body 1.

A cap 15 is attached to the cylindrical part 16 of the main body 1 on the inlet side with bolts 17, etc., and is attached to the circumferential wall 1.
8 is brought into contact with the bush 8 and the disc spring 12 is bent to press the bush 7 against the inlet side main body 1 to form seal surfaces C and D.

Reference numeral 19 denotes a resin passage, which is formed in the outlet side main body 3 and connects an annular passage 20 formed between the bushes 7 and 8 to a connecting pipe 11 that extends to a die (not shown). In the figure, 21 is a heater, and 22 is a plug.

In this embodiment configured in this way, the molten resin supplied from the connecting pipe 4 flows through the resin passage 2, passes through the communication hole 6, is guided from the annular passage 20 and the resin passage 19 to the connecting pipe 5, It is supplied to a die (not shown).

As the die moves, the outlet main body 3 rotates integrally with the bushes 7 and 8 relative to the inlet main body 1, but the above-mentioned feeding state is maintained at this time as well.

In addition, as shown in FIG. 2, the outer peripheral wall 1 of the cap 15
8 is brought into contact with the bush 8 and the elastic member 12 is pre-flexed to provide an appropriate initial sealing pressure, so that the outer circumferential wall 18 of the cap 15 and the bush 8
A sealing surface C is formed between the ends of the bush 7 and a sealing surface D is formed between the end of the bush 7 and the main body 1 on the inlet side.

Here, when the resin pressure in the resin passage 2 becomes higher than the initial setting sealing pressure, the thrust force in the direction of arrow A is increased by the resin pressure as shown in FIG.
However, since this thrust force changes in proportion to the resin pressure, a sealing pressure commensurate with the resin pressure is generated on the sealing surfaces C and D, making it possible to prevent resin leakage.

Also, when the resin pressure increases, bushes 7 and 8
The resin pressure that also acts on the thin-walled portion 9 causes the thin-walled portion 9 to bend and expand outward, so that a sealing pressure commensurate with the resin pressure is generated on the sealing surface B, making it possible to prevent resin leakage. can.

As described in detail in the embodiments above, the present invention has a seal/bearing member divided into bushes,
Thin-walled parts are formed on the opposing outer peripheral walls of these bushes, and an elastic member is installed between these bushes and the main body on the outlet side, so that even if the resin pressure in the resin passage changes, it will be able to match the resin pressure. Appropriate sealing pressure can be obtained, eliminating the risk of resin leakage.

Therefore, the conventional operation of tightening and adjusting the nut every time resin leaks is no longer necessary, improving operability and productivity. Furthermore, since it is not necessary to tighten the nut strongly from the beginning with a large expectation of the maximum resin pressure, a large driving force is not required to rotate the outlet side main body, and economical efficiency is also improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional example, Figs. 2 to 4 show an embodiment of the present invention, Fig. 2 is a sectional view thereof, and Fig. 3 is a sectional view taken along the line of Fig. 2. ,
FIG. 4 is a partially enlarged sectional view of the FIG. 2 section. 1: Inlet side main body, 2: Resin passage, 3: Outlet side main body, 7, 8: Bush, 9: Thin wall portion, 12: Elastic member.

Claims (1)

[Scope of utility model registration request] An inlet body has a resin passageway connected to the extruder at one end, and a communication hole provided at the other end of the resin passageway opens to the die side, and a seal and bearing member is connected to the outside of the inlet body. A fitted and rotatable outlet side body, a through hole connecting the outlet side body to a communicating hole in the inlet side body, and the seal/bearing member are pressed in the axial direction via an elastic member to seal. In the rotary joint equipped with a pressing member, the seal-cum-bearing member is a bush divided in the axial direction of the resin passage,
A rotary joint characterized in that an elastic member is installed between the outlet side main body and the bush, and a thin wall portion is formed on the opposing outer peripheral wall of the bush.