JPH0886362A - Seal structure of bearing portion - Google Patents

Abstract

PURPOSE: To provide the seal structure of a bearing portion whose durability is high by restraining the generation of frictional heat by making slide smooth by sliding each seal ring between the inside surfaces of each recessed groove of a drive shaft through each resin film of a low friction coefficient. CONSTITUTION: In a case in which a drive shaft 1 and a housing 2 are rotated relatively, a seal ring 6 in a seal groove 1b follows the housing 2 and is rotated due to radial difference between its inner and outer peripheries. This seal ring 6 slides in the state of being pressingly contacted to the bottom surface and the low pressure side surface of the seal groove 1b at the drive shaft 1 through a resin film 5. The frictional coefficient of polytetrafluoroethylene to be used for the resin film 5 is extremely lower than that of polyphenylenesulfide which is the resin material of the drive shaft 1, so the seal ring 6 slides very smoothly and the generation of frictional heat is sufficiently small, and even in the case of the resin material being used for the drive shaft 1, the durability of the seal structure of a bearing portion can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial bearing portion in which a shaft and a bearing rotate relative to each other, and to a seal structure for sealing the movement of fluid through the bearing portion.

[0002]

2. Description of the Related Art When a rotational force is taken out from the inside of various kinds of equipment, or when a rotating device portion provided inside the equipment is rotationally driven from the outside, a rotary shaft is inserted into a circular hole formed in a casing of the equipment. It is necessary to take out the rotational force or drive the internal rotating device by this rotating shaft. In a device equipped with such a rotary drive mechanism, the internal pressure is often high, so that the high-pressure fluid existing in the casing does not leak outside, and the outer surface of the rotary shaft and the inner circumference of the circular hole are prevented. It is necessary to provide a seal device for the bearing to maintain the sealability between the surfaces.

FIG. 6 is a schematic view showing a seal structure of a bearing portion which has been conventionally used. In this seal device, a drive shaft 1 is provided in a circular hole 2c formed in a housing 2 constituting the device.
And the concave groove 1b is formed over the entire outer surface of the drive shaft 1.
And the seal ring 6 is fitted in the groove 1b to seal the groove. This seal ring 6
Is formed of an elastic material such as rubber as an annular body having an X-shaped cross section,
The structure is such that the inner peripheral edge is fitted into a groove 1b formed on the outer peripheral surface of the drive shaft 1 over the entire circumference thereof and slidably contacted with each other with a slight gap therebetween. A flat plate ring-shaped backup ring is inserted into the groove 1b so as to be adjacent to the seal ring 6 so that the seal ring 6 is biased by the pressure in the device and fits into the gap of the bearing portion. In some cases, measures are taken to prevent this.

[0004]

Here, the above-mentioned bearing seal is used.
Focusing on the bearing portion in the ring structure, as shown in FIG. 7, the outer peripheral surface of the seal ring 5 is the bearing 2 a of the housing 2.
The peripheral length (2πr ₁ ) of the surface in contact with the inner peripheral surface of is larger than the peripheral length (2πr ₂ ) of the surface in which the inner peripheral surface of the seal ring 6 contacts the bottom surface of the seal groove 1b of the drive shaft 1. Therefore, since the friction resistance is larger on the outer peripheral surface side of the seal ring 6, the seal ring 6 slides between the seal ring 6 and the bottom surface of the seal groove 1b and is driven by the housing 2 side. Also,
When the difference in rotation speed becomes large and the pressure inside the equipment becomes high, the seal ring 6 is urged to the side opposite to the high pressure side (low pressure side) as shown in FIG. 1
Sliding also occurs between the side surface on the low pressure side in b. When such sliding occurs, frictional heat is generated due to slippage between the seal ring 6 and the bottom surface of the seal groove 1b or the side surface on the low pressure side.

By the way, in the conventional seal device for a bearing, both the drive shaft 1 and the housing 2 are made of a steel material having extremely high heat resistance.
No problem occurred even if frictional heat was generated inside. However, recently, there has been a demand for reducing the weight by making the drive shaft 1 side used in the drive device synthetic resin. And when performing such resinization,
Since the drive shaft 1 transmits power, a resin material having high mechanical strength such as PPS (polyphenylene sulfide) is selected.

However, since the resin material such as PPS whose material is selected with priority given to the strength standard cannot obtain sufficiently high heat resistance, when it is used as the drive shaft 1, When frictional heat is generated due to the sliding as described above, as shown in FIG. 8, the resin material on the bottom of the seal groove 1b and the side surface on the low-pressure side may become uneven due to wear or thermal deformation, which may reduce the sealing effect. There was a problem that there is. For example, in the bearing seal structure shown in FIG. 6, when the relative rotation speed of the drive shaft 1 and the housing 2 is set to a low speed of 50 rpm in a room temperature environment, a test is performed.
In this case, there is no particular problem because the amount of frictional heat generated is small, but when the rotation speed is increased to a high speed of 1000 rpm, the sliding portion becomes hot and the seal groove 1b is formed in a short time.
An uneven shape will be generated inside. Further, in an atmosphere of 100 ° C. or higher, uneven shapes may occur in the seal groove 1b even at a relatively low speed.

In view of the above-mentioned circumstances, the present invention provides a bearing portion which can withstand sliding with the seal ring by coating the sliding surface of the synthetic resin drive shaft with the seal ring with fluororesin or the like. It is intended to provide a seal structure.

[0008]

In order to solve the above-mentioned problems, the seal structure of the bearing has a shaft member made of a resin material and a metal which is relatively rotatable by fitting the shaft member. A bearing portion formed of a bearing member made of a material, wherein a seal groove is formed in the fitting portion of the outer peripheral surface of the shaft member over the entire circumference in the circumferential direction, and a ring-shaped seal made of an elastic body. The ring is inserted into this seal groove,
In a seal structure in which the inner and outer peripheries of the shaft are brought into pressure contact with the bottom surface of the seal groove and the inner peripheral surface of the bearing member, at least the sliding surface of the shaft member on the inner side surface of the seal groove with the seal ring is made of a resin material of the shaft member. Is also coated with a protective resin material having a low friction coefficient and / or high heat resistance.

Further, the seal structure of the bearing portion is constituted by a shaft member made of a resin material and a bearing member made of a metal material which is fitted in the shaft member and is relatively rotatable. A seal groove is formed in the fitting portion of the inner peripheral surface of the bearing member over the entire circumference in the circumferential direction, and a ring-shaped seal ring made of an elastic body is inserted into the seal groove, In a seal structure in which the inner and outer peripheries of the shaft member and the bottom surface of the seal groove are brought into pressure contact with each other, at least the surface of the outer peripheral surface of the shaft member facing the seal groove of the bearing member has more friction than the resin material of the shaft member. It is characterized by being coated with a protective resin material having a low coefficient and / or a high heat resistance.

Further, the shaft member is made of polyphenylene sulfide, and the protective resin material is polytetrafluoroethylene.

[0011]

[Operation] When the shaft member and the bearing member rotate relative to each other,
The seal ring in the seal groove is driven by the bearing member to rotate due to the difference in inner and outer radii, and slides with respect to the shaft member. However, in the means, the inner surface of the seal groove of the shaft member on which the seal ring slides is coated with the protective resin material, and in the means, the outer peripheral surface of the shaft member on which the seal ring slides is protected by the protective resin material. Is coated by. Here, when the protective resin material has a low coefficient of friction, the friction resistance of the seal ring becomes smaller than that when sliding on the original resin material of the shaft member, so that the sliding becomes smooth. At the same time, the generation of frictional heat is suppressed, and it is possible to prevent the sliding portion of the shaft member from being worn or thermally deformed. Further, when the protective resin material has high heat resistance, the original resin material of the shaft member can be protected against the frictional heat generated by the sliding of the seal ring.

In a further means, PPS having a high mechanical strength and relatively high heat resistance is used as the resin material of the shaft member, and a protective resin material for coating is used.
Since a fluororesin (for example, polytetrafluoroethylene resin) having a friction coefficient sufficiently lower than that of PPS and high heat resistance is used, the friction resistance is small even at high speed rotation and can withstand sliding with the seal ring even in a high temperature atmosphere. It may be a resin bearing seal.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention. FIG. 1 is a partial vertical sectional view of a seal structure of a bearing portion of the present invention, and FIG. 2 is a part showing a seal structure of the bearing portion. FIG. 3 is an enlarged vertical sectional view, and FIG. 3 is a partial sectional perspective view showing a drive shaft and a seal ring. The constituent members having the same functions as those of the conventional example shown in FIGS. 6 to 8 are designated by the same reference numerals.

In this embodiment, a seal structure of a bearing portion in a drive unit will be described. The seal structure of the bearing portion includes a drive shaft 1 which is a shaft member, and a housing 2 which is a bearing member which is fitted with the drive shaft 1 and is relatively rotatable.
Consists of The housing 2 is a substantially cylindrical bearing member made of steel, and the fitting holes formed at both ends serve as bearings 2a, and the pressure chamber 2b having a large inner diameter is formed between the bearings 2a. Has been formed. On the other hand, the drive shaft 1 is a shaft member made of PPS (polyphenylene sulfide), and both sides thereof are fitted into both bearings 2 a of the housing 2 with a clearance fit, and are relatively rotatable with the housing 2. Then, as described with reference to FIG. 6, in the pressure chamber 2b, the spline 2c and the spline 1a are formed on the inner peripheral surface of the housing 2 and the outer peripheral surface of the drive shaft 1, respectively, and the outer plate 3 and the inner plate 4 are formed. Are engaged and silicone oil is filled with a small amount of air.

The housing 2 may be made of a metal material other than steel. The drive shaft 1 may be made of a resin material having high mechanical strength other than PPS.

A seal groove 1b is formed on the outer peripheral surface of the drive shaft 1 facing the bearings 2a of the housing 2 along the entire circumference in the circumferential direction. Then, as shown in detail in FIG. 2, PTFE (polytetrafluoroethylene), which is a fluororesin, is formed on the inner surface of the seal groove 1b.
Is coated to form a resin film 5. PT
FE is a resin material having a friction coefficient sufficiently lower than that of PPS used for the drive shaft 1 and high heat resistance. This P
The TFE coating is performed by applying a fluororesin-based coating material and curing it, but it is also possible to coat it by sticking a PTFE sheet or the like. The resin film 5 formed by this coating needs to be formed at least on the bottom surface on the inner side surface of the seal groove 1b and the side surface on the opposite side (low pressure side) from the pressure chamber 2b, but in the figure, it is on the pressure chamber 2b side (high pressure side). Side) is also formed on the side surface.
Further, the resin coating 5 may be formed not only on the inner side surface of the seal groove 1b but also on the outer peripheral surface of the drive shaft 1 around it.

A seal ring 6 formed by molding an elastic material such as rubber into a ring shape having an X-shaped cross section as shown in FIG. 3 is inserted into the seal groove 1b. Since the width between the inner and outer circumferences of this seal ring 6 is slightly thicker than the depth of the seal groove 1b, when the drive shaft 1 is fitted into the bearing 2a of the housing 2, the inner and outer circumferences thereof are sealed. And the inner peripheral surface of the bearing 2a. Therefore, the silicone oil with which the pressure chamber 2b is filled is sealed by this seal ring 6, thereby forming the seal structure of the bearing portion. In addition, the seal ring 6 is
As shown in FIG. 2, when the pressure inside the pressure chamber 2b becomes high, it is urged to the low pressure side. Therefore, this seal ring 6
Is pressed against the bottom surface of the inner side surface of the seal groove 1b and the side surface on the low-pressure side, so that it always contacts these surfaces via the resin coating 5.

By the way, in the seal groove 1b, in order to prevent the seal ring 6 from being caught in the gap between the seal ring 6 and the bearing 2a when the seal ring 6 is urged to the low pressure side, A flat ring backup ring may be inserted. In this case, since the seal ring 6 is pressed against the low-pressure side surface of the seal groove 1b via the backup ring, it is not always necessary to form the resin coating 5 on the low-pressure side surface. However, in this case, it is preferable that the backup ring is made of the same resin material as the resin coating 5.

The seal ring 6 is not limited to an X ring having an X-shaped cross section, and a lip seal having a U-shaped cross section or a D ring having a D-shaped cross section may be used. Also,
The cross-sectional shape of the seal groove 1b is not limited to the rectangular shape shown in the drawing, but may be an appropriate concave shape according to the shape of the seal ring 6.

In the seal structure of the bearing portion having the above structure, when the drive shaft 1 and the housing 2 rotate relatively, the seal ring 6 in the seal groove 1b is driven by the housing 2 due to the difference in the inner and outer radii. And then rotate. Therefore, the seal ring 6 slides while being pressed against the bottom surface of the seal groove 1b of the drive shaft 1 and the side surface on the low pressure side via the resin coating 5. However, this resin coating 5
Is a resin material of the drive shaft 1
Since the coefficient of friction is extremely lower than that of PS, the seal ring 6 slides very smoothly and frictional heat is sufficiently reduced.

As a result, according to the seal structure of the bearing portion of this embodiment, the seal ring 6 slides smoothly through the resin coating 5, so that the abrasion of the inner surface of the seal groove 1b due to this slide is reduced. In addition, the generation of frictional heat is suppressed, so that the occurrence of thermal deformation can be prevented. Therefore, there is no fear that the inner surface of the seal groove 1b will be uneven due to such wear and thermal deformation, and the sealing effect will be reduced. Even when a resin material is used for the drive shaft 1, the durability of the seal structure of the bearing portion is reduced. It becomes possible to improve the sex.

As a result of conducting a comparative experiment between the seal structure of the bearing portion of this embodiment and a conventional seal structure using PPS for the drive shaft 1, either the drive shaft 1 or the housing 2 is kept in a room temperature environment. When the relative speed was set to 50 rpm, which was a low speed, in both cases, the uneven shape due to wear or thermal deformation was hardly generated on the inner surface of the seal groove 1b. But,
When the relative rotation speed test of low speed 50 rpm, medium speed 100 rpm, and high speed 1000 rpm was performed for 3 seconds in the atmosphere of high temperature 150 ° C., in the conventional example, the concavo-convex shape was generated in all cases. In each of the examples, the uneven shape hardly occurred. Therefore,
The seal structure of the bearing portion of this embodiment can be sufficiently used for a short time even under the severe condition of 1000 rpm in the atmosphere of 150 ° C.

4 and 5 show a second embodiment of the present invention. FIG. 4 is a partial longitudinal sectional view of a seal structure of a bearing portion of a drive unit, and FIG. 5 is a seal structure of the bearing portion. FIG. The first shown in FIG. 1 and FIG.
Constituent members having the same functions as those in the embodiments are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the seal structure of the bearing portion in the seal structure of the bearing portion similar to that of the first embodiment will be described. However, here, the case where the seal groove shown in the first embodiment is formed on the bearing 2a side of the housing 2 is shown.

As shown in FIG. 4, the seal grooves 2 are formed on the inner peripheral surfaces of both bearings 2a of the housing 2 over the entire circumference.
d is formed. The seal rings 6 similar to those of the first embodiment are inserted into the seal grooves 2d,
The inner and outer circumferences thereof are pressed against the bottom surface of the seal groove 2d and the outer peripheral surface of the drive shaft 1 to form a seal structure. A backup ring may be inserted into the seal groove 2d on the low pressure side of the seal ring 6.

As shown in detail in FIG. 5, the outer peripheral surface of the drive shaft 1 facing the seal groove 2d of the housing 2 is coated with PTFE similarly to the inner surface of the seal groove 1b in the first embodiment. Thus, the resin coating 5 is formed. The resin coating 5 may also be formed on another portion of the outer peripheral surface of the drive shaft 1.

In the seal structure of the bearing portion having the above structure, when the drive shaft 1 and the housing 2 rotate relative to each other, the seal ring 6 follows the housing 2 to rotate, and the resin on the outer peripheral surface of the drive shaft 1 rotates. It slides while being pressed against the coating 5. However, the PT used for this resin coating 5
Since FE has a coefficient of friction extremely lower than that of PPS, which is a resin material of the drive shaft 1, the seal ring 6 slides very smoothly, and friction heat is sufficiently generated.

As a result, even in the case of the seal structure of the bearing portion of this embodiment, the seal ring 6 smoothly slides through the resin coating 5 to suppress the generation of frictional heat, so that it is driven by wear or thermal deformation. There is no risk that the outer peripheral surface of the shaft 1 will be uneven and the sealing effect will be reduced, and the durability of the seal structure of the bearing portion can be improved even when a resin material is used for the drive shaft 1.

The resin coating 5 preferably has a lower friction coefficient and a higher heat resistance than the resin material of the drive shaft 1, and the drive shaft 1 shown in the first and second embodiments is made of PP.
The optimum combination is one in which S is used and PTFE is used for the resin coating 5. However, this resin coating 5 is
Other resin materials may be used as long as they have a friction coefficient lower than that of the above resin material. In addition, polyamide (P) having higher heat resistance than the resin material used for the drive shaft 1
It is also possible to use a resin material such as A) type or polyimide (PI) type. In this case, the effect of suppressing the generation of frictional heat cannot be expected so much, but the occurrence of thermal deformation due to this frictional heat can be prevented, so that it is possible to prevent the drive shaft 1 from becoming uneven. Further, depending on the resin material of the drive shaft 1, it is possible to use a urethane (PUR) resin material for the resin coating 5.

In the above first and second embodiments, the seal structure of the bearing portion of the drive device is shown, but any other seal structure can be used as long as it is a seal structure for sealing the fluid in the rotating bearing portion. It can also be applied to the seal structure of the bearing portion.

[0031]

As is apparent from the above description, according to the seal structure of the bearing portion of the present invention, the friction resistance when the seal ring slides is reduced by the protective resin material coated on the shaft member, Alternatively, since the resin material of the shaft member is protected from the frictional heat generated by sliding, it is possible to prevent the sliding effect of the shaft member from being worn or thermally deformed and the sealing effect from being deteriorated. The effect of being able to raise.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention and is a partial vertical cross-sectional view of a seal structure of a bearing portion.

FIG. 2 shows a first embodiment of the present invention and is a partially enlarged vertical sectional view showing a seal structure of a bearing portion.

FIG. 3 is a partial sectional perspective view showing a drive shaft and a seal ring according to the first embodiment of the present invention.

FIG. 4 shows a second embodiment of the present invention and is a partial vertical cross-sectional view of the seal structure of the bearing portion.

FIG. 5 shows a second embodiment of the present invention and is a partially enlarged vertical sectional view showing a seal structure of a bearing portion.

FIG. 6 shows a conventional example and is a longitudinal sectional view of a seal structure of a bearing portion.

FIG. 7 shows a conventional example and is a partially enlarged vertical sectional view showing a seal structure of a bearing portion.

8 is a partially enlarged vertical cross-sectional view showing a conventional example and showing a case where a concavo-convex shape is generated on the inner side surface of the seal groove in FIG.

[Explanation of symbols]

 1 Drive shaft 1b Seal groove 2 Housing 2d Seal groove 5 Resin coating 6 Seal ring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Higashi 663 Minoshima, Arita-shi, Wakayama Mitsubishi Cable Industries, Ltd.Minoshima Works (72) Inventor Daimei Matsui 663 Minoshima, Arita, Wakayama Mitsubishi Cable Industries, Ltd. Minoshima Works

Claims (3)

[Claims] 1. A bearing portion comprising a shaft member made of a resin material and a bearing member made of a metal material which is fitted into the shaft member and is relatively rotatable, the outer peripheral surface of the shaft member. A seal groove is formed in the fitting portion of the entire circumference in the circumferential direction, and a ring-shaped seal ring made of an elastic body is inserted and fitted in the seal groove, and the inner and outer circumferences of the seal groove and the bottom surface of the seal groove In a seal structure that is pressed against the inner peripheral surface of the member, at least the sliding surface of the inner surface of the seal groove of the shaft member with the seal ring has a lower friction coefficient than the resin material of the shaft member and / or heat resistance. Sealing structure for bearings, characterized by being coated with a highly protective resin material. 2. A bearing portion composed of a shaft member made of a resin material and a bearing member made of a metal material which is fitted into the shaft member and is relatively rotatable, the inner circumference of the bearing member. A seal groove is formed in the fitting portion of the surface over the entire circumference in the circumferential direction, and a ring-shaped seal ring made of an elastic body is inserted and fitted in the seal groove, and the inner and outer circumferences of the seal groove are the outer peripheral surface of the shaft member. In the seal structure in which the seal groove and the bottom surface of the seal groove are pressed against each other, at least the surface of the outer peripheral surface of the shaft member facing the seal groove of the bearing member has a lower friction coefficient and / or heat resistance than the resin material of the shaft member. Sealing structure for the bearing part, which is coated with a highly protective resin material. 3. The seal structure for a bearing according to claim 1, wherein the shaft member is made of polyphenylene sulfide, and the protective resin material is polytetrafluoroethylene.