KR20120002135A - Ptfe oil seal with no adhesive and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A glueless PTFE(PolyTetra Fluoro Ethylene) oil seal and a manufacturing method thereof are provided to simplify a manufacturing process for an oil seal and reduce the contamination of a mold by attaching rubber and PTFE resin without an adhesive. CONSTITUTION: A glueless PTFE oil seal(100) comprises a support frame(120), a rubber rib(110), and a PTFE resin rib(130). The rubber rib comprises a main body(111) which surrounds at least a part of the support frame and a dust lip part(116) which surrounds a part of the exterior of a rotary shaft by being extended from the main body. The resin rib comprises an adhesive part(131) which is directly attached to the rubber rib without an adhesive and a main rib part(136) which is extended from the adhesive part and surrounds a part of the exterior of the rotary shaft.

Description

PTFE OIL SEAL WITH NO ADHESIVE AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to an oil seal, and is applied to a vehicle, a machine tool, and the like, and relates to a non-adhesive PTFE oil seal and a manufacturing method thereof for preventing leakage of working oil.

The oil seal is to prevent oil leakage in a general rotating device. The oil seal has a variety of structures depending on the type of rotating device. The oil seal used to prevent leakage of the rotating shaft generally includes a support frame, a main body, and a spring.

The support frame is made of a metal material and serves to support the oil seal, which is embedded in the body or coupled to one side of the body. The main body is formed to surround the outer surface of the rotating shaft, a lip is formed on the inner side of the main body. The spring is disposed on the outer surface of the main body such that the lip and the rotating shaft contact, and the lip is elastically pressed toward the rotating shaft. An example of the oil seal may be a crankshaft seal used in an automobile engine.

The main body of the crankshaft seal has been composed of an acrylic rubber composition, but recently, due to the miniaturization of the engine, severe operating environment due to high performance, and development of engine oil that can be used for a long time, the fluorine rubber composition having excellent heat resistance and oil resistance This is applied a lot.

By the way, the said fluororubber composition is expensive. Accordingly, price competitiveness is low.

In addition, the oil seal includes a spring, there is a problem that the spring is separated from the body in the process of being assembled to the rotating shaft or transported. In addition, the conventional oil seal has a problem in that the manufacturing cost increases because the spring must go through the process of producing the spring, the process of coupling the spring to the body.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a non-adhesive PTFE oil seal excellent in oil resistance and heat resistance, and a method of manufacturing the same, as a low cost material.

Another object of the present invention is to provide a non-adhesive PTFE oil seal which does not require a spring and a manufacturing method thereof.

A non-adhesive PTFE oil seal according to a preferred embodiment of the present invention for achieving the above object is an oil seal that prevents leakage of oil between the housing and a rotating shaft that rotates with respect to the housing, the support frame, a rubber lip, Resin granules. The support frame is rigid. The rubber lip includes a main body portion disposed to surround at least a portion of the support frame, and a dust lip portion extending from the main body portion to surround a portion of an outer surface of the rotation shaft. The resin lip includes an adhesive part bonded to the main body of the rubber lip, and a main lip part extending from the adhesive part to surround a part of the outer surface of the rotating shaft, and is made of PTFE material.

In this case, the main lip of the resin lip is a plate shape located closer to the center of the rotation axis than the dust lip of the rubber lip, the insertion portion is formed in the body portion of the rubber lip so that the adhesive portion of the resin lip is inserted and seated. Can be.

In addition, the main lip may be formed to extend from the adhesive portion in contact with the rotating shaft 3mm to 8mm.

In addition, a plurality of groove grooves may be formed in a portion of the main lip contacting with the rotating part.

 The non-adhesive PTFE oil seal may not include a separate spring.

According to another aspect of the present invention, there is provided a method for preparing a non-adhesive PTFE oil seal, comprising: preparing 80 to 95 parts by weight of tetrahydrofuran, 1 to 10 parts by weight of naphthalene, and 1 to 10 parts by weight of metal sodium to prepare a mixed solution, and a plate Immersing a resin lip made of a PTFE material of the shape into the mixed solution to activate a surface, and removing residual tetrahydrofuran and residual naphthalene from the resin lip after the deposition, the resin lip, and an acrylic material The rubber lip and the support frame are bonded.

In this case, the step of adhering the resin lip, the acrylic rubber which is a rubber lip material, and the support frame is preferably made through a vulcanization mold.

In addition, in the step of adhering the resin lip, the rubber lip, and the support frame, it is preferable to form groove grooves in a portion in contact with the rotation axis of the resin lip.

 In addition, the step of activating the surface by immersing the resin lip in the mixed solution, it is possible to immerse the resin lip in the mixed solution for 10 to 30 minutes.

In addition, the step of removing the residual tetrahydrofuran and residual naphthalene from the resin lip, natural drying the resin lip for 1 to 2 hours, washing the resin lip with running water, and drying 2 to 7 times It may include repeating the steps.

In another aspect of the present invention, the non-adhesive PTFE oil seal is an oil seal which prevents leakage of oil between a crankshaft housing and a crankshaft that rotates with respect to the crankshaft housing. A rubber lip of acrylic rubber material including a main body portion disposed to surround the frame, a dust lip portion extending from the main body portion to surround a portion of an outer surface of the crankshaft, and a separate adhesive portion of the main body of the rubber lip And a resin lip made of PTFE material including a directly bonded adhesive part and a main lip part extending from the adhesive part to surround a part of the outer surface of the crankshaft.

According to the present invention, by incorporating a low-cost rubber and a PTFE resin and applying it in place of the fluororubber composition, the manufacturing cost is low, and oil resistance and heat resistance are excellent.

In addition, by adhering the rubber and the PTFE resin without the adhesive, the oil seal manufacturing process is simplified, and mold contamination due to the adhesive is reduced.

In addition, in the non-adhesive PTFE oil seal according to the present invention, the spring is omitted, so that the spring is not separated from the rubber lip in the process of being mounted between the rotating shaft and the housing or transported, and manufacturing cost is reduced.

1 is a perspective view showing a portion of the non-adhesive PTFE oil seal according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the non-adhesive PTFE oil seal shown in FIG. 1. FIG.
Figure 3 is a flow chart illustrating a non-bonded PTFE oil seal manufacturing method according to a preferred embodiment in another aspect of the present invention.
Figures 4a to 4d is a conceptual diagram showing each step of the non-bonded PTFE oil seal manufacturing method of the present invention.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a perspective view showing a portion of a non-adhesive PTFE oil seal according to an embodiment of the present invention, Figure 2 is a cross-sectional view of the non-adhesive PTFE oil seal shown in FIG.

1 and 2, the adhesive-free PTFE oil seal 100 according to the present invention to prevent the leakage of oil between the housing 10 and the rotating shaft 20 that rotates relative to the housing 10 Silver comprises a rubber lip 110, a support frame 120, and a resin lip 130.

The rubber lip 110 is interposed between the housing 10 and the rotation shaft 20 to prevent leakage. The rubber lip may be made of a soft rubber material, for example, an acrylic rubber composition.

The rubber lip 110 includes a main body 111 and a dust lip 116. The main body 111 is interposed between the housing 10 and the rotation shaft 20. The body portion is fixedly bonded to the support frame 120 to be described later.

The dust lip 116 extends from the main body 111 so as to surround a part of the outer surface of the rotation shaft 20. The dust lip portion 116 is continuously formed in a lip shape along the circumference of the rotation shaft 20.

The dust lip part 116 protrudes from the main body part 111 to the rotation shaft 20 to prevent the dust contained in the atmosphere from flowing between the housing 10 and the rotation shaft 20. The dust lip portion 116 is formed outside the main lip portion 136 which will be described later, and is continuously formed in a lip shape along the circumference of the rotation shaft 20. Here, the outer means the direction away from the oil-filled area in the housing 10. Accordingly, while the rotation shaft 20 rotates with respect to the dust lip portion 116 of the rubber lip, it is possible to prevent the main lip portion 136, which will be described later, from being worn by foreign matter.

The dust lip 116 is preferably formed to be elastically deformed by interference with the rotation shaft 20. This is to increase the effect of preventing foreign matter from flowing between the rotation shaft 20 and the dust lip portion 116.

As shown in FIG. 1, an example of the shape of the dust lip 116 for this purpose may be inclined at a predetermined angle toward the rotation shaft 20. This structure allows the dust lip 116 to increase the sealing effect between the housing 10 and the rotation shaft 20. As described above, in the non-adhesive PTFE oil seal 100 of the present invention, the dust lip portion 116 and the rotation shaft 20 are contacted by a predetermined area by interference with each other to seal the rubber lip 110 and the rotation shaft 20. To be able.

The support frame 120 is bonded to the main body 111. The support frame 120 allows the shape of the rubber lip 110 made of a soft material to be maintained. The support frame 120 may be formed in an annular shape, and the center of the support frame 120 is formed to pass through the rotation shaft 20. The support frame 120 is preferably formed of a rigid material, for example, a metal material, so as to increase the effect of supporting the rubber lip 110.

The resin lip 130 includes an adhesive part 131 and a main lip part 136. The adhesive part 131 is adhesively formed on the main body part 111 of the rubber lip. In this case, the main body portion 111, the insertion groove 112 is formed in the portion corresponding to the adhesive portion 131 is inserted and seated, the adhesive portion 131 is inserted into the insertion groove 112. It can be arranged so as not to protrude outward.

The main lip portion 136 extends from the adhesive portion 131 and is formed to surround a part of the outer surface of the rotation shaft while having a clearance with the dust lip portion 116. The main lip 136 prevents the working oil operating along the rotation shaft 20 from escaping to the outside.

An example of the working oil may be engine oil applied to a crankshaft of an automobile. The engine oil circulates outside the crankshaft, thereby minimizing frictional losses of the crankshaft, which translates the reciprocating motion of the piston into rotational motion due to the explosion of the in-cylinder mixer in an internal combustion engine such as a gasoline engine or a diesel engine.

In this case, the resin lip 130 is made of PTFE (PolyTetra Fluoro Ethylene) resin. The PTFE resin has excellent heat resistance and oil resistance at least at the same level as fluorine rubber. Therefore, oil leakage can be properly prevented even in harsh ambient environments.

In addition, by contacting with the outside relatively in contact with the oil, the dust strip portion requiring a relatively low oil resistance and heat resistance is made of an acrylic rubber composition. The material cost of the acrylic rubber is lower than the material cost of the fluororubber.

The present invention uses a large portion of a conventional body made of fluorine rubber as an acrylic rubber which is a relatively inexpensive material, and locally uses a PTFE resin only at a portion requiring oil resistance and heat resistance in contact with a rotating shaft. Therefore, the cost to manufacture the non-adhesive PTFE oil seal of the present invention is lower than that of fluorine rubber, resulting in excellent price competitiveness.

In addition, the resin lip 130 may be manufactured in a plate shape of a PTFE resin material. Since the PTFE resin has an elastic force, a portion of the plate becomes an adhesive portion, and the other portion is bent along the rotation axis to form a main lip portion. This simplifies the shape structure of the rubber lip and the resin lip.

On the other hand, the area (H) that the main lip 136 and the rotating shaft 20 is in contact is preferably formed to be 3mm to 8mm. When the main lip 136 is in contact with the rotating shaft 20 by 3 mm or less, the contact area between the main lip 136 and the rotating shaft 20 is reduced, and thus cannot serve as a sealing role, and the friction force is small to separate You will need a spring. In addition, when the main lip 136 is in contact with the rotation shaft 20 by 8 mm or more, the friction force with the rotation shaft 20 is increased, thereby generating sliding heating between the rotation shaft and the oil seal, thereby causing the main lip 136 to be in contact with the rotation shaft 20. Can promote hardening. The main lip 136 may be in sufficient contact with the rotating shaft 20 to prevent leakage of oil between the housing 10 and the rotating shaft 20.

The non-adhesive PTFE oil seal 100 according to the present invention having the above structure does not require a spring for pressing the main body 111 toward the rotating shaft 20. This is because the main lip portion 136 of the resin lip 130 is sufficiently in contact with the rotating shaft. Accordingly, the non-adhesive PTFE oil seal 100 according to the present invention does not occur when the spring is separated from the rubber lip 110 in the process of being mounted or transported between the rotating shaft 20 and the housing 10. In addition, the non-adhesive PTFE oil seal 100 according to the present invention manufactures a spring, and the process of mounting the spring on the rubber lip 110 is omitted, thereby reducing the manufacturing cost.

On the other hand, it is preferable that a plurality of groove grooves 137 are formed in a portion of the main lip 136 in contact with the rotating part. The grooves 137 are to increase the sealing effect of the main lip 136. As an example of the groove grooves 137 for this purpose, it is formed concave at regular intervals from the surface in contact with the rotating shaft 20. In addition, the groove grooves 137 are continuously formed along the circumference of the rotation shaft 20. That is, the groove grooves 137 are formed in a ring shape at regular intervals.

In another modification of the groove 137, the groove 137 may be concave in a screw shape. The screw line is preferably formed to be inclined in a direction opposite to the direction in which the rotating shaft 20 rotates along the circumference of the rotating shaft 20. This shape is such that the oil between the main lip 136 and the rotating shaft 20 does not flow out to the outside by the main lip 136 while the rotating shaft 20 is in contact with the main lip 136 and rotates. This is to allow inflow. Here, the inside is an area filled with oil in the housing 10.

When groove grooves 137 are formed in the main lip portion, the dust lip also serves to prevent the foreign matter from filling the groove grooves 137.

The adhesive portion 131 is preferably bonded to the body portion of the rubber lip without a separate adhesive. That is, in order to bond between the PTFE resin and the acrylic rubber, an adhesive may be used in general, but in this case, the adhesive may be filled in the grooves 137 or overcoated. When the adhesive is filled in the groove grooves 137, the sealability is lowered as if the groove grooves 137 are not present. Moreover, when the said adhesive agent is apply | coated excessively, the height of the interface surface between the groove grooves 137 will change, and sealing property will fall.

To this end, the resin lip 130 is preferably etched before adhering to the rubber lip 110.

According to the present invention, the adhesive part 131 is directly adhered to the main body part 111 without an adhesive, thereby solving the above problem. To this end, the rubber lip and the resin lip 130 can be simultaneously vulcanized in the same vulcanization mold, and can be bonded without an adhesive. When the acrylic rubber composition of the rubber lip 110 material and the PTFE resin of the resin lip 130 are put into the vulcanization mold and heat and pressure are applied for a predetermined time, the rubber lip and the resin lip 130 are bonded to each other. . This will be described later in detail.

Hereinafter, in another aspect of the present invention, a method for producing a non-adhesive PTFE oil seal of the above structure will be described.

In the method for preparing a non-adhesive PTFE oil seal of the present invention, as shown in FIG. 3, 80 to 95 parts by weight of tetrahydrofuran, 1 to 10 parts by weight of naphthalene, and 1 to 10 parts by weight of metal sodium are mixed to prepare a mixed solution. Step (S10), and by immersing the resin lip made of the plate-shaped PTFE material in the mixed solution, to activate the surface (S20), and after the deposition, to remove the residual tetrahydrofuran and residual naphthalene from the resin lip And a step (S40) of adhering the resin lip, the rubber lip of the acrylic rubber material, and the support frame without a separate adhesive.

  According to the present invention, after activating the surface of the PTFE resin, it can be adhered to the acrylic rubber without adhesive. Through this, the bonding process is eliminated, thereby simplifying the process. In addition, although the treatment is required after the adhesion treatment within the effective period, the adhesion period is eliminated, so that the effective period becomes longer. In addition, mold contamination due to the adhesive is prevented. In addition, the adhesive can prevent the filling and over-application into the groove of the resin lip 130 at the source, thereby ensuring the sealing property.

Each step will be described in detail with reference to FIGS. 4A to 4D. First, as shown in FIG. 4A, 80 to 95 parts by weight of tetrahydrofuran (THF, Tetrahydrofuran), 1 to 10 parts by weight of naphthalene, and 1 to 10 parts by weight of the metallic sodium is mixed to prepare a mixed solution 210. In this case, after the said tetrahydrofuran, naphthalene, and metal sodium are put into the mixing container 200, it can mix by stirring for 8 to 10 hours. This dissolves sodium and naphthalene.

Thereafter, as shown in FIG. 4B, the resin lip 130 is immersed in the mixed solution 210 to activate the surface. In this case, the resin lip 130 has a plate shape as a PTFE resin. When the resin lip 130 is deposited, chemical etching occurs by the mixed solution. When the chemical etching occurs, the resin lip surface is activated, and thus can be bonded without a separate adhesive in the bonding step to be described later.

In this case, the time for depositing the resin lip in the mixed solution is preferably 10 minutes to 30 minutes. This is because if the time is 10 minutes or less, the etching does not occur sufficiently, and if it exceeds 30 minutes, the surface activation proceeds too much, which hinders the bonding process.

Thereafter, as shown in FIG. 4C, a step of removing residual tetrahydrofuran and residual naphthalene from the resin lip is performed. This is to remove residual solids. Residual solids are preferably removed before the bonding step, since they interfere with proper bonding in the subsequent bonding step.

To this end, as shown in FIG. 4c, the resin lip 130 is naturally dried for 1 to 2 hours, the resin lip is washed with running water 220, and the drying is repeated 2 to 7 times. The steps can be performed. Through the natural drying step, the residual liquid can be removed by volatilization. In particular, residual tetrahydrofuran in the residual liquid can be removed.

In addition, the step of washing the resin lip 130 with running water and repeating the drying step 2 to 7 times is to remove the residual solids and the absorbed content inside the resin lip with gas. In other words, when the resin lip is washed with running water, residual solids are removed. In addition, when the washed resin lip 130 is dried for 3 hours or more, preferably about 4 hours at ambient conditions of 100 ℃, it is possible to remove the absorbed water as a gas inside the PTFE resin material. By repeating the above steps several times, it is possible to remove residual solids and PTFE internal absorbents that hinder adhesion.

Thereafter, as shown in FIG. 4D, the rubber lip 110, the support frame 120, and the resin lip 130 are made of an adhesive without adhesive.

In this case, the bonding step may be performed together with the vulcanization process in the vulcanization mold. That is, the support frame 120 and the resin lip 130 are mounted in the cavity formed between the upper plate 2 and the lower plate 3, and the acrylic rubber is inserted into the rubber lip position. After that, if heat is applied for a predetermined time through the vulcanization process, the rubber lip 110 and the resin lip 130 can be fixed without an adhesive. In this case, the working temperature in the vulcanization mold may be 200 ° C to 250 ° C, and the vulcanization time may be 30 seconds to 60 seconds.

Meanwhile, an uneven portion may be formed in the lower plate such that groove grooves are formed in a portion in contact with the rotating shaft of the resin lip 130. Through this, the resin lip 130 is coupled with the rubber lip 110 and simultaneously grooves the grooves. It can be formed.

According to the present invention, the PTFE material is etched and surface activated, and the adhesive is bonded to the acrylic rubber in the vulcanization mold, thereby eliminating a separate adhesive.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

100: non-adhesive PTFE oil seal
110: rubber lip
111: main body
116: dust lip
120: support frame
130: resin lip
131: adhesive
136: main rib
137: groove groove

Claims (10)

An oil seal for preventing leakage of oil between a housing and a rotating shaft rotating relative to the housing,
Rigid support frame;
A rubber lip made of a rubber material including a main body portion disposed to surround at least a portion of the support frame, and a dust lip portion extending from the main body portion to surround a portion of an outer surface of the rotating shaft; And
A resin lip made of PTFE (PolyTetra Fluoro Ethylene) material including an adhesive part directly bonded to the main body of the rubber lip without an adhesive, and a main lip part extending from the adhesive part to surround a part of the outer surface of the rotating shaft;
Non-adhesive PTFE oil seal comprising a. The method of claim 1,
The main lip of the resin lip has a plate shape located closer to the center of the rotation shaft than the dust lip of the rubber lip,
Non-adhesive PTFE oil seal, characterized in that the insertion groove is formed in the main body portion of the rubber lip so that the adhesive portion of the resin lip is inserted and seated. The method of claim 2,
The main lip portion is a non-adhesive PTFE oil seal, characterized in that extending from the adhesive portion in contact with the rotating shaft 3mm to 8mm. The method of claim 2,
Non-adhesive PTFE oil seal, characterized in that the portion in contact with the rotating portion of the main lip portion is formed with a plurality of groove grooves. The method of claim 1,
And the housing is a crankshaft housing, and the rotating shaft is a crankshaft that rotates with respect to the crankshaft housing. As a method of manufacturing a non-adhesive PTFE oil seal having the structure of any one of claims 1 to 5,
Preparing a mixed liquid by mixing 80 to 95 parts by weight of tetrahydrofuran, 1 to 10 parts by weight of naphthalene, and 1 to 10 parts by weight of metallic sodium;
Immersing a resin lip made of a plate-shaped PTFE material in the mixed solution to activate a surface;
Removing residual tetrahydrofuran and residual naphthalene from the resin lip after the deposition; And
Bonding the resin lip, an acrylic rubber lip, and a support frame;
Non-adhesive PTFE oil seal manufacturing method comprising a. The method of claim 6,
And the step of adhering the resin lip, the acrylic rubber which is a rubber lip material, and the support frame is performed through a vulcanization mold. The method of claim 6,
In the step of adhering the resin lip, the rubber lip, and the support frame, a groove of a non-adhesive PTFE oil seal, characterized in that for forming a groove groove in a portion of the PTFE resin. The method of claim 6,
The step of activating the surface by immersing the resin lip in the mixed solution, immersing the resin lip in the mixed solution for 150 minutes to 30 minutes, characterized in that the method for producing a non-adhesive PTFE oil seal. The method of claim 6,
Removing residual tetrahydrofuran and residual naphthalene from the resin lip,
Naturally drying the resin lip for 1 to 2 hours; And
Washing the resin lip with running water and repeating the drying step 2 to 7 times;
Non-adhesive PTFE oil seal manufacturing method comprising a.

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