JP2006183609A - Seal means and ejector having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal ring with high seal performance which solves the problem of seal leakage in an ejector such as a conventional gear pump. <P>SOLUTION: A seal means 20 comprises a plurality (four) of seal rings 20a-20d for preventing unvulcanized rubber from leaking in a direction of a rotational shaft 12 of a gear pump or an extruder. The seal rings are sequentially arranged outward along the rotational shaft 12 with a minute space of 0.03 mm or less between neighboring seal rings. The rotational shaft 12 has step differences. The inside diameter of the seal ring is formed so that the seal ring arranged on the outside of the rotational shaft 12 has a smaller inside diameter according to the step differences. In the pressurized unvulcanized rubber, a flow is blocked due to flow resistance by a gap between seal rings and a gap between each seal ring and a step difference part. In the ejector such as a gear pump, the pressurized fluid such as a rubber material is completely prevented from leaking through the seal means. A breakage or the like of a bearing in the ejector by leaked fluid is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a discharge device such as a gear pump, a rubber extruder, or the like, and to a discharge device including a plurality of stages of seal rings that prevent fluid leakage in the direction of the rotation axis, and a discharge device including the seal device. is there.

In a gear pump that extrudes a highly viscous material such as unvulcanized rubber or an extruder that directly attaches a gear pump to the tip of the extruder and discharges the rubber with a gear pump and extrudes it from a die. Various kinds of sealing means are applied to the rotating shaft so that a material such as rubber filled in is not leaked to the outside.
As such sealing means used in the gear pump, various types are known as schematically shown in FIG.
That is, (1) using an O-ring in which a seal made of an elastic body is hermetically arranged around a rotating shaft (for example, refer to Patent Document 1), (2) used for a gear motor similarly. An elastic body such as an oil seal is arranged in a sealing manner around the rotation axis (see Patent Document 2), (3) A non-elastic body is arranged in a sealing manner around the rotation axis, and the elasticity of the metal is utilized. Metal seals, (4) labyrinth seals (see Patent Document 3) are known.

  However, in these conventional sealing means, when a highly viscous fluid such as unvulcanized rubber is to be discharged by, for example, a gear pump, a rubber or the like is generated from a physical gap between these seals and the outer wall of the rotary shaft housing portion. It is unavoidable that a part of the gas pump leaks out, so that there is a problem that the gear pump bearing is damaged by the leaked rubber or the like.

  Therefore, in a conveying device such as a highly viscous rubber, as shown in FIG. 4 which is a longitudinal sectional view as viewed from above, the gear side shaft end portions 112a, 112b and 113a, 113b of the gear shaft are disposed inside. There are provided the return feed lines 120, 121, 122, 123 formed in a spiral shape, whereby the pressurization that has entered the gap between the shaft end portions 112a, 112b, 113a, 113b and the gap plates 103, 105 It is known that the rubber material is again fed back into the working air space between the gears of the transport mechanisms 102 and 103 (see Patent Document 4).

In this device, in order to prevent the leaked rubber from damaging the bearing, the feed efficiency of the return feed line is not sufficient, and if the material enters the gap, the leaked rubber material is returned to the return pipe line. 120, 121, 122, 123 are collected in the storage chambers 114a, 114b, 114c, 115a, 115b, 115c formed between the bearings 108, 109, 110, 111 and lead-out conduits 116, It is necessary to derive from 117 to the outside of the apparatus. For this reason, there is a problem in that the apparatus becomes complicated and expensive because a helical return path and a separate outlet chamber from the storage chamber or the storage chamber must be provided on the rotation shaft of the gear.
JP-A-11-62852 JP 2003-214359 A JP-A-10-47260 JP-A-5-340359

The present invention has been made to solve the problem of seal leakage in such a conventional discharge device such as a gear pump. The purpose of the present invention is to pressurize a pressurized fluid such as a rubber material in the discharge device such as a gear pump. It is possible to completely prevent leakage from the fluid and to eliminate damage to the bearing of the discharge device due to the leaked fluid.

The invention of claim 1 is a sealing means for preventing leakage of fluid in the direction of the rotation axis of the discharge device, wherein the seal means is provided with a step so as to have a smaller diameter outward from the discharge mechanism of the discharge device. It is characterized by comprising a plurality of seal rings having an inner diameter corresponding to the diameter of the rotating shaft and arranged at a predetermined minute interval with respect to the rotating shaft.
According to a second aspect of the present invention, in the sealing means according to the first aspect, the plurality of seal rings are arranged so as to be independently rotatable around the rotation shaft, and are provided at a predetermined distance from a step side surface of the rotation shaft. It is characterized by being arranged at a minute interval.
According to a third aspect of the present invention, in the sealing means according to the first or second aspect, the predetermined minute gap is 0.03 mm or less.
According to a fourth aspect of the invention, there is provided the sealing means according to any one of the first to third aspects, further comprising means for pressing the plurality of seal rings against each other.
A fifth aspect of the present invention is the sealing means according to any one of the first to fourth aspects, wherein the fluid is unvulcanized rubber.
A sixth aspect of the present invention is a discharge device comprising the sealing means according to any one of the first to fifth aspects.

(Operation) Pressurization such as pressurized unvulcanized rubber is performed by setting a gap between seal rings mounted on a rotating shaft of a discharge device such as a gear pump to a predetermined minute interval that is preferably 0.03 mm or less. Even if fluid flows in between the seal rings, it can be prevented from passing through.
In particular, a step is provided on the rotary shaft of the discharge device, and the inner diameter of the seal ring is formed correspondingly to the step of the rotary shaft from the discharge mechanism of the fixed discharge device to the outside, that is, the bearing. Even if the pressurized fluid flows into the seal ring close to the discharge mechanism, the inflow of the seal ring in the next stage is narrowed by the inflow, and the inflow of the pressurized fluid can be surely prevented. The minute gap between the circumferential surface of the stage seal ring prevents the pressurized fluid from leaking more reliably.

According to the present invention, it is preferable that the pressurized fluid leaked from the discharge mechanism cannot pass between the seal rings even if the plurality of seal rings enter the seal area along the rotation axis. Since it is formed at a minute interval of 0.03 mm or less, leakage can be completely blocked, and troubles such as damage to the bearing do not occur. Further, since the sealing means is composed of a plurality of stages of seal rings having different inner diameters corresponding to the steps of the rotating shaft, it is preferably 0 between the step side surface of the rotating shaft and the circumferential surface of the next stage seal ring. A small gap of 0.03 mm or less can reliably prevent the leakage of pressurized fluid.
Furthermore, from the viewpoint of required sealing performance and cost, it is possible to set the optimum step of the rotating shaft and the number of steps of the seal ring corresponding thereto, and complete sealing performance can be obtained while minimizing the cost.

An embodiment of a sealing means according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a gear pump that is a constant-volume discharge device provided with a sealing means according to the present embodiment. The gear pump 1 includes a gear 10 constituting a fixed amount discharge mechanism, a rotary shaft 12 integrally connected to the gear 10, a bearing 14 attached to a housing 16 for supporting the rotary shaft 12, and the gear 10. The seal means 20 is provided between the seal means 20 and the bearing 12. The seal means 20 is provided between the seal means 20 and the bearing 12. 12 and a collar 18 fitted in the shaft hole 19 of the gear pump housing 16 to engage with the outermost seal ring end side surface of the plurality of stages of seal rings and press the seal rings against each other. ing.

  FIG. 1B is an enlarged cross-sectional view of a part (in a circle) of the seal ring 20 of FIG. 1, and the seal rings 20 a, 20 b, and 20 c are steps 12 a, 12 b, and 12 c of the rotating shaft 12, respectively. Corresponding to the above, the inner diameter of the gear 10 becomes smaller in order from the outer side toward the outer side. By reducing the inner diameter of each seal ring 20 to such an extent that it is arranged outside the apparatus, a seal can be formed between each seal ring 20 and the stepped portion of the rotary shaft 12. Further, in this configuration, since the shaft diameter of the rotating shaft 12 is closer to the gear 10 side, a portion where a large torque acts on the rotating shaft can be reinforced, and as a result, a large torque can be transmitted. There are advantages.

  Here, experience has shown that when the gap between the seal rings 20 is 0.03 mm or less, the pressurized unvulcanized rubber cannot pass through the gap, so the minute gap is 0.03 mm or less. It is preferable to make it.

FIG. 2 is an enlarged cross-sectional view showing a part of the sealing means 20 shown in FIG.
The sealing means 20 is shown here as having three stages of seal rings 20a-20c. That is, the seal rings 20a to 20c are arranged concentrically with the rotary shaft 12, and the inner diameters thereof are directed to the bearing direction in correspondence with the steps 20a to 20b of the rotary shaft 12 of the gear 10 constituting the discharge mechanism. The outer diameters are formed to be equal to each other, and the outer diameters are successively reduced.

  The first to third seal rings 20a to 20c are arranged with a minute gap of 0.03 mm or less, for example, and are closely arranged with the same minute gap with respect to the respective steps 12a and 12b of the rotating shaft 12. Has been. Further, the collar 18 (FIG. 1) presses the outer periphery of the seal ring 20 c in the direction of the gear 10, so that the seal rings 20 a to 20 c and the seal rings 20 a to 20 c and the stepped portion of the rotary shaft 12. The gaps between 12a and 12b can also be reliably held in the minute gap state.

  In the gear pump having the sealing means configured as described above, a part of the pressurized unvulcanized rubber flows out along the rotating shaft 12 of the gear pump, passes between the first seal ring 20a and the rotating shaft 12, Furthermore, when the minute gap between the first seal ring 20a and the second seal ring 20b of the sealing means 20 is forced open and flows into the second seal ring 20b, the unvulcanized rubber flows into the second seal ring 20b. The gap with the third seal ring 20c is closed by being strongly pressurized by the inflow pressure of rubber.

  In addition, in order for the unvulcanized rubber that has passed between the first seal ring 20a and the rotary shaft 12 to enter the outside, that is, the bearing side, the second seal ring 20b and the step 12a of the rotary shaft are in contact with each other. It must pass through the gap, and this portion is also held in the minute gap of 0.03 mm or less as described above, and thus cannot pass through. Even if there is a leakage, the unvulcanized rubber closes the gap between the second seal ring 20b and the step 12a of the rotating shaft 12 with its own pressure, that is, the discharge pressure of the gear pump acting on itself. Therefore, it does not flow out beyond the third seal ring 20c. If leakage still occurs, it is possible to increase the number of steps of the rotating shaft and the number of steps of the seal ring 20 as necessary. Therefore, the unvulcanized rubber that has flowed in passes through the passage formed by the minute gaps and becomes a bearing. It is completely prevented from flowing to the side.

  As described above, in the sealing means according to the present embodiment, the gap between the seal rings is set to such a small size that the pressurized rubber cannot pass through in the first place, and the unvulcanized rubber leaks outside through these gaps. Although it does not, even if it forcibly passes a part of the seal ring, the rubber has the effect of completely blocking the intrusion of the subsequent rubber by closing the seal ring with its own pressure, As in the prior art, there is no problem of leaking in the direction of the rotary shaft 12 of the gear pump and damaging the bearing 14.

It is a longitudinal cross-sectional view of the gear pump to which the sealing means of this invention is applied. It is an expanded sectional view of a sealing means. It is sectional drawing which shows the conventional sealing means. It is the longitudinal cross-sectional view which looked at the conventional pressurization conveyance apparatus from the top.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gear pump, 10 ... Gear pump gear, 11 ... Feed roll, 12 ... Rotary shaft of gear pump, 12a-12c ... Step part of rotary shaft, 14 ... Bearing, ..Gear pump housing, 18 ... collar, 19 ... shaft hole, 20 ... sealing means. 20a-20d ... Seal ring.

Claims (6)

Seal means for preventing fluid leakage in the direction of the rotation axis of the discharge device,
The sealing means has an inner diameter corresponding to the diameter of the rotary shaft provided with a step so as to become a small diameter outward from the discharge mechanism of the discharge device, and is arranged at a predetermined minute interval from the rotary shaft. A sealing means comprising a plurality of seal rings. The sealing means according to claim 1,
The sealing means, wherein the plurality of seal rings are disposed so as to be independently rotatable around the rotation shaft, and are disposed at a predetermined minute distance from a step side surface of the rotation shaft. The sealing means according to claim 1 or 2,
The sealing means characterized in that the predetermined minute gap is 0.03 mm or less. The sealing means according to any one of claims 1 to 3,
Sealing means comprising means for pressing the plurality of seal rings against each other. The sealing means according to any one of claims 1 to 4,
The sealing means characterized in that the fluid is unvulcanized rubber.   A discharge device comprising the sealing means according to any one of claims 1 to 5.

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