JPH10318375A - Seal ring for rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress that oil invades between an outer peripheral surface of a seal ring and a cylinder, and suppress abrasion by setting a gradient of an outer peripheral surface which abuts on the cylinder to a specified angle, when the diameter of a seal ring for a rotor arranged in an annular groove formed on a shaft is enlarged by fluid pressure. SOLUTION: In a seal ring 30 arranged in an annular groove 22 of a shaft 20 which is rotatably housed in a cylinder 10, a gradient of an outer peripheral surface 32 on the basis of a pressure receiving surface 34a on which an action of fluid pressure P is applied is suppressed to ±1 deg. and less, and it is suppressed that the fluid pressure P is applied between the outer peripheral surface 32 and the cylinder 10. Since an area of contact the outer peripheral surface 32 of the seal ring 30 with the cylinder 10 is larger than an area contact an end surface (a temporary pressure receiving surface) 34b with an inner wall surface 24 of a shaft 20, the seal ring 30 is not rotated unless the fluid pressure P is not applied between the outer peripheral surface 32 and the cylinder 10. It is thus possible to solve such a problem that the cylinder 10 is damaged by rotary sliding of the seal ring 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal ring used for sealing a fluid between a relatively rotating shaft and a cylinder, for example, an automatic transmission (AT, CVT) of an automobile and the like. Also, the present invention relates to a sealing technique for a rotating body in a power steering device or the like.

[0002]

2. Description of the Related Art In a torque converter, an oil pump, a hydraulic clutch, an oil distributor, and the like of an automatic transmission such as an AT car and a CVT car, hydraulic fluid leaks into a relative rotating portion between a stationary member and a rotating member. A seal ring is adopted to control the pressure. FIG. 9A showing an example thereof.
The shaft (2) is rotatably housed in a cylinder (1) as a stationary member, and a seal ring (3) is arranged in an annular groove (2a) formed on the outer peripheral surface of the shaft (2). is there. The cylinder (1) has a through-hole (1b) connected to a hydraulic pressure introduction pipe (4) to introduce hydraulic oil from outside. An oil discharge passage (2b) communicating with the outer peripheral surface is formed inside the shaft (2).

The seal ring (3) has a rectangular cross section and a shaft (2).
And is arranged in the annular groove (2a) of FIG.
Ended expandable ring with an abutment (cut) (3p). Accordingly, when hydraulic oil is introduced from the oil introduction pipe (4), as shown in FIG. 9B, the hydraulic pressure (P) is applied to one end surface (pressure receiving surface: 3a) and the inner peripheral surface (3) of the seal ring (3). 3b), the other end surface (anti-pressure receiving surface: 3c) of the seal ring (3) is pressed against the inner wall surface (2b) of the annular groove (2a), and the diameter of the seal ring (3) is increased. The outer peripheral surface (3d) is pressed against the inner peripheral surface (1a) of the cylinder (1). Thereby, the rotating shaft (2)
A seal is made between the cylinder and the cylinder (1).

[0004] In addition to having a sufficient sealing property, the seal ring (3) does not damage the mating material (cylinder (1) and / or shaft (2)) with which the seal ring slides.
It is required not to increase the torque in order to improve fuel efficiency.

[0005]

Heretofore, when a mating member with which a seal ring is in contact is soft, a method of performing sealing while allowing an appropriate oil leak for lubrication has been generally adopted. However, in recent years, a soft material such as an ADC (aluminum alloy for die-casting) has been frequently used for a cylinder and / or a shaft in accordance with a demand for a lightweight AT, and a mating material with which the seal ring comes into contact is such a soft material. In such a case, there is a limit to preventing damage to the partner material while reducing the amount of oil leak.

[0006] Therefore, the object of the present invention is based on the finding that the mating member of the seal ring is damaged due to the rotational sliding of the seal ring, and based on the finding that the seal ring does not cause the rotational slide. Therefore, even if the mating material is a soft material, the material is not damaged.

[0007]

SUMMARY OF THE INVENTION A seal ring for a rotating body according to the present invention is injection-molded from a synthetic resin, and is a seal ring having an end which can be expanded and contracted, so that it is incorporated into an annular groove formed on the outer peripheral surface of a shaft. In order to seal between the cylinder and the shaft rotatably housed in the cylinder, it is disposed in an annular groove formed in the shaft and expanded by fluid pressure. The inclination of the outer peripheral surface in contact with the cylinder is set to ± 1 ° or less.
By making the gradient of the outer peripheral surface of the seal ring ± 1 ° or less, it becomes difficult for oil to enter between the outer peripheral surface of the seal ring and the cylinder. As a result, rotational sliding does not occur between the cylinder and the seal ring, and rotational sliding occurs between the inner wall surface of the annular groove of the shaft and the end surface of the seal ring. Therefore, wear of the cylinder made of the soft material is suppressed.

Here, the direction of the gradient of the outer peripheral surface of the seal ring does not matter. That is, it may be either a downward slope toward the end face (pressure receiving surface) on the side receiving the action of the fluid pressure or a downward slope toward the end face (anti-pressure receiving face) on the side not receiving the action of the fluid pressure. .

A second aspect of the present invention is characterized in that the cross-sectional shape of the outer peripheral surface of the rotary body seal ring is concave. In this case, the oil is held in the concave portion on the outer peripheral surface of the seal ring, which is useful for lubrication when the seal ring slides with respect to the cylinder, which is advantageous in reducing the wear of the cylinder.

The invention of claim 3 is characterized in that the hardness of the seal ring for the rotating body is HRM 70 or more.
In order to reduce the wear of the seal ring itself, because the seal ring slides between the shaft without rotating and sliding on the cylinder, and because the seal ring may slide on the cylinder. Appropriate hardness is required.

According to a fourth aspect of the present invention, the synthetic resin is one synthetic resin selected from the group consisting of an aromatic polyetherketone resin, a polyarylene sulfide resin, an aromatic polyimide resin, and a polyamideimide resin. There is a feature.

[0012] The invention of claim 5 is characterized in that the seal ring for the rotating body is manufactured by heat setting after injection molding. In the heat setting step, the molded product after injection molding is inserted into a ring gauge and heated with the cylindrical body inserted inside the molded product, so that the outer peripheral surface of the molded product is pressed against the inner peripheral surface of the ring gauge. Therefore, the outer peripheral surface of the molded product is plastically deformed in accordance with the inner peripheral surface of the ring gauge, and the gradient of the outer peripheral surface is as small as possible in the heat-fixed seal ring as the final product.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below, taking as an example a case where a cylinder is stationary and a shaft rotates. Contrary to this, the case where the shaft is stationary and the cylinder rotates may be used, and it goes without saying that the present invention can be applied to any part where the shaft and the cylinder make a relative rotational movement.

FIG. 1 shows an embodiment of the present invention, which is disposed in an annular groove (22) formed on the outer peripheral surface of a shaft (20) rotatably housed in a cylinder (10). Figure 2 shows a somewhat exaggerated cross section of the seal ring (30) shown. The basic configuration is the same as that of the conventional seal ring (3) described with reference to FIGS. 9 and 10, except that the gradient (Δθ) of the outer peripheral surface (32) is set to ± 1 ° or less. ing. That is, both end faces (34a, 34
b), the gradient of the outer peripheral surface (32) with respect to the end surface on the side receiving the action of the fluid pressure (P), that is, the outer peripheral surface (32) with respect to the pressure receiving surface (34a) is suppressed to ± 1 ° or less, and the outer peripheral surface (32) (10) makes it difficult for the fluid pressure to act. Fluid pressure acts on the pressure receiving surface (34a) and the inner peripheral surface (36) of the seal ring (30), and the seal ring (30) is formed on the anti-pressure receiving surface (34b) by the annular groove (22) of the shaft (20). Pressed against one of the inner wall surfaces (24) and the outer peripheral surface (3).
It is pressed against the cylinder (10) in 2). Normal,
The contact area between the outer peripheral surface (32) of the seal ring (30) and the cylinder (10) is the end surface (anti-pressure receiving surface: 34b) of the seal ring (30) and the inner wall surface (24) of the shaft (20).
The seal ring (30) is hard to rotate unless fluid pressure acts between the outer peripheral surface (32) and the cylinder (10). Therefore, even when the material constituting the cylinder (10) is a soft material such as an ADC, there is no possibility that the cylinder (10) is damaged by the rotational sliding of the seal ring (30).

As used herein, the term "soft material" means, for example, an aluminum alloy such as ADC, a cast metal such as spheroidal graphite cast iron,
Any material such as surface-hardened and surface-nitrided products such as steels containing carbon-based materials such as S-C and SCM-based materials, or hardened low-hardness products, and resin materials may be used. Means that the surface hardness is, for example, Brinell hardness (measurement condition example, standard material 10 mm sphere, load 3000 kgf).
It is a soft metal-based material having a hardness of 0 to 500, specifically 70 to 300, and about 75 to 200 depending on the type of the metal-based material. Note that the measurement conditions in parentheses above are preferable measurement conditions, and may be measured by another measurement method.

As shown in FIGS. 2 (a) and 2 (b), if the cross-sectional shape of the outer peripheral surface (32) of the seal ring (30) is made concave, the shape shown in FIGS. Hydraulic pressure (P) is larger than that of the seal ring (30)
Hard to act on. Moreover, in this case, the concave portions (32a, 32b) formed on the outer peripheral surface (32) serve as oil reservoirs, and contribute to lubrication when the seal ring (30) slides on the cylinder (10), for example. I do.

The seal ring (30) has ends, and the shape of the abutting portions (38i) (38j) facing each other is a composite step shape. That is, FIG.
As shown in (b), the rectangular cross section at the abutment part is shaped like a square.
At the time of division, at least one or a pair of protrusions (38m) are formed on two rectangular cross-sections of one of the abutments (38i) on the outer peripheral surface (32) side of the seal ring (30).
And a notch (38n), and the other notch (38q) and the protrusion are fitted to the other abutment (38j) and the one protrusion (38m) and the notch (38n), respectively. (38p) is formed. Then, the protrusion (38m) and the notch (38q), and the notch (38n) and the protrusion (38p) are fitted to each other, and the abutments (38i) and (38j) are fitted. A pair of protrusions (3
8p) and (38m) seal ring
It is preferable to be able to be incorporated into a shaft or the like regardless of the pressure receiving surface side and the counter pressure receiving surface side. As described above, in the case of the end seal ring, if the abutting shape is used, the fluid leakage amount is very small, so it can be said that it is excellent, but other abutting shapes, for example, step cut, angle cut, straight The opening may have any shape such as cut.

In the case of a seal ring having an abutting portion, as shown in FIG. 6, at least a butt portion of the outer peripheral surface of the sealing ring abutting portion as shown in FIG. In particular, the outer peripheral end (38r) of the protrusion (38m) (38p) at the seal ring abutment may have a gentle curved shape or chamfered shape.

By adopting such a shape, it can be expected that abnormal wear of the cylinder (10) due to the abutting edge of the seal ring can be prevented. The dimension of such a gentle curved shape (13r) or chamfered shape is, for example, 1 to 50% of the outer diameter of the seal ring, preferably 5%.
If the amount is about 25%, it is considered that the cylinder (10) is less likely to be damaged by the edge of the outer peripheral butted portion of the seal ring abutment.

The surface roughness (arithmetic mean roughness) of the surface of the seal ring (30) in contact with the mating member is, for example, 0.1 to 2.0.
It is set to 5 μmRa, preferably 0.1 to 1.5 μmRa, more preferably 0.3 to 1.3 μmRa, still more preferably 0.7 to 1.0 μmRa. The surface having such a surface roughness may be either a surface facing the soft material or a surface facing a member harder than the soft material. However, in order to prevent damage to the soft material, at least the soft surface is used. It is preferable that the surface roughness of the surface in contact with the material is within the above range.

The material constituting the seal ring (30) is not particularly limited as long as it has heat resistance. For example, the following heat-resistant synthetic resin material can be used.

(A) polyetherketone resins such as polyethernitrile resins, polycyanoarylether resins, polyetheretherketone resins, (whole) aromatic thermoplastic polyimide resins, polyamideimide resins,
A group consisting of polyarylene sulfide-based resins such as polyamide 4-6 resin or polyphenylene sulfide resin (these have high heat resistance, high flame resistance, excellent mechanical and oil resistance, chemical resistance, and injection moldability. 90 to 50% by weight of any one resin selected from the group consisting of: a resin used for forming a seal ring; 10 to 50% by weight of a reinforcing fiber such as a carbon fiber; A main component is 2 to 25% by weight of at least one kind of lubricity imparting agent such as a fluorine-based resin such as a resin, or a molybdenum-based compound such as molybdenum disulfide, and if necessary, 10 to 40% by weight of powdered talc. Resin composition.

(B) polyetherketone resins such as polyethernitrile resins, polycyanoarylether resins, polyetheretherketone resins, (all) aromatic thermoplastic polyimide resins, polyamideimide resins,
90-50% by weight of any one resin selected from the group consisting of a polyarylene sulfide-based resin such as polyamide 4-6 resin or polyphenylene sulfide resin, 10-50% by weight of a reinforcing fiber such as a carbon-based fiber,
2 to 25% by weight of at least one kind of lubricity-imparting agent such as a fluorine-based resin such as a regenerated ethylene tetrafluoride resin or a molybdenum-based compound such as molybdenum disulfide, if necessary; 10-4
A resin composition containing 0% by weight as a main component.

(C) 30 to 82% by weight of the above heat-resistant synthetic polymer (polyetherketone resin, polyarylene sulfide resin, etc.), 5 to 45% by weight of reinforcing fiber such as carbon fiber, and fluorine resin, or And a resin composition containing at least one or more lubricating agents such as molybdenum compounds such as molybdenum disulfide.

(D) The above heat-resistant synthetic polymer (polyetherketone resin, polyarylene sulfide resin, etc.)
30 to 82% by weight, 5 to 45% by weight of reinforcing fiber such as carbon fiber, 2 to 25% by weight of fluorine resin such as recycled tetrafluoroethylene resin, and if necessary, 10 to 40% by weight of powdered talc A resin composition comprising:

(E) The above heat-resistant synthetic polymer (polyetherketone resin, polyarylene sulfide resin, etc.)
30 to 82% by weight, 5 to 45% by weight of reinforcing fiber such as carbon fiber, 2 to 25% by weight of fluorine resin such as regenerated tetrafluoroethylene resin, and if necessary, molybdenum compound 1 such as molybdenum disulfide 1 A resin composition containing 10% by weight and, if necessary, 10 to 40% by weight of powdered talc.

(F) 10 to 40% by weight of the above powdery talc
A mixture containing 10 to 40% by weight of a calcium powder filler in place of the above.

(G) A mixture of 5-45% by weight of aromatic polyamide fiber instead of 5-45% by weight of carbon fiber.

(H) 5 to 45% by weight of an aromatic polyamide fiber is blended in place of 5 to 45% by weight of the carbon fiber, and calcium-based filler 10 is replaced in place of 10 to 40% by weight of powdered talc. A resin composition containing about 40% by weight.

These resin composition groups have a normal use atmosphere temperature of, for example, normal temperature (20 to 25 ° C.) or more, specifically 80 to 300 ° C., practically 100 to 200 ° C., and a fluid such as oil. It is preferable because it shows good sliding characteristics even when sliding under pressure.

When the filler has an average particle size of, for example, 1 to 50 μm, preferably 5 to 25 μm, the filler is substantially uniformly dispersed and compounded in the resin composition. For example, the ADC 12) is considered to be less damaging.

Concretely, a seal ring comprising the above composition
Explaining the characteristics of the injection molded article, for example, the melting point is 28
0-480 ° C, heat distortion temperature is ASTM D-648
(1.81 MPa) at 230 to 430 ° C,
Further, the flexural strength is 100 under the condition of ASTM D-790.
~ 300MPa, preferably 100 ~ 150MPa, song
Under the conditions of ASTM D-790.
20000 MPa, preferably 4000 to 20000 M
Pa, hardness is ASTM D785 (Rockwell hardness,
M60 to M120, preferably M70
~ M100, linear expansion coefficient by TMA method (1-5) x 1
0^-Five/ ° C, preferably (1.5-3.5) × 10 ^-Five/ ° C
At least one of the physical property values in the range, preferably
Of three or more, more preferably all
It is preferably a molded article. The above measurement method is
Although this is a preferred measurement method, it is
Instead, any measurement method may be used.

If the melting point and the heat distortion temperature are at the above-mentioned level, for example, when the hydraulic clutch in the AT is in use and the temperature is 8
The temperature rises to 0 to 180 ° C, and the seal ring is used for the piston (rotating shaft) and cylinder (housing) of the hydraulic clutch.
Sufficient heat resistance can be expected even when heated by rotating and sliding with a mating material such as. Further, if the bending strength and the bending elastic modulus are at the above-mentioned levels, it is expected that the seal ring can be prevented from being damaged in relation to the configuration of the present invention. If the surface hardness is about the above, the hydraulic pressure becomes, for example, 0.5 to 2.5 MPa during use of the hydraulic clutch, so that even if the seal ring is pressed against the piston or cylinder of the hydraulic clutch by the hydraulic pressure, it is not sufficient. It is considered that mechanical properties such as creep resistance can be maintained for a long time. If the coefficient of linear expansion is about the above, the amount of dimensional change is small at low temperature, normal temperature, and high temperature, so that the amount of oil leak is substantially constant under each temperature condition.

The resin composition having the above physical properties and an apparent melt viscosity of 10 ² to 10 ⁵ poise at a shear rate of 10 ² to 10 ⁴ (sec ^-1 ) in the molten state is obtained. Suitable for injection moldability and preferred. With such a melt viscosity, for example, the width (B) and the thickness (T) of the rectangular cross section of the seal ring are 1 to 3 mm, preferably 1.4 to
2.6 mm, outer diameter (D) is 10 to 300 m
m, preferably a seal ring having a relatively long developed length of 25 to 150 mm can be formed by injection molding.

Here, the skin layer of the seal ring injection-molded body after the heat treatment is useful for improving the mechanical strength and wear resistance of the seal ring injection-molded body. When the member surface slides in contact, it is expected that a soft counterpart material having relatively low hardness may be damaged depending on the use conditions. In order to avoid such a situation, the reinforcing layer may be removed by surface processing such as cutting, and the surface on which such cutting has been performed and the soft material mating member may slide.

The carbon-based fiber is a pitch-based fiber, PAN
System, carbonaceous, or graphitic, for example, a fiber diameter of about 4 to 20 μm and a fiber length of about 10 to 1 μm.
If it is 000 μm, preferably 10 to 500 μm, it is suitable because it is uniformly dispersed in the resin composition and sufficiently reinforced.

In consideration of appropriate mechanical properties such as elastic modulus and tensile strength, aggressiveness to a counterpart material such as a cylinder and a shaft, and fluidity of a resin composition at the time of molding, the average carbon fiber diameter is about 1 μm.
Preferably, the fiber length is 0 to 20 μm and the fiber length is about 10 to 500 μm. Further, in order to obtain a sliding material in oil having particularly excellent wear resistance, it is preferable to employ a material having an average fiber diameter of 10 μm or more. The average fiber diameter of the carbon fibers varies depending on the raw material, but pitch fibers correspond to carbon fibers having an average fiber diameter of 10 μm or more. Since the pitch-based carbon fiber has preferable strength and hardness characteristics, it can be expected that both a suitable reinforcing effect of the seal ring and a point that the soft mating member is not damaged are achieved.

When the PAN-based carbon fiber and the pitch-based carbon fiber are compared, the tensile strength of the PAN-based carbon fiber is 2400 MPa, while that of the pitch-based carbon fiber is 590 to 980 MPa.
And the tensile modulus is 200 to 500 GP in the PAN system.
a is 30-300 GP for pitch type
a, and 30 to 40 GPa, and there is a large difference in mechanical strength between the two, but there is no problem as the seal ring according to the present invention. However, in consideration of the damage to the soft material, those made of pitch-based carbon fibers are preferable.

A small amount of PAN-based carbon fiber may be mixed with the carbon fiber, and the average fiber diameter of all the used carbon fibers does not necessarily need to be 10 μm. When a small amount of PAN-based carbon fiber is mixed, the wear resistance of the seal ring is improved, and the seal ring is less likely to be broken when incorporated into a shaft. However, it is considered that the mixing ratio of the PAN-based carbon fiber is limited to 30% by weight.

The proportion of the carbon fiber in the total composition is 5 to 50% by weight. If the amount is less than 5% by weight, the mechanical strength and abrasion resistance of the resin composition are not improved, and if the amount is more than 50% by weight, the melt fluidity is remarkably reduced and the injection moldability is deteriorated.

Further, virgin PTFE powder or recycled P
Better results are obtained with TFE powder. Playback P
Since the TFE powder is a powder obtained by baking the virgin material once and then pulverizing it, it does not significantly increase the melt viscosity of the resin composition as when PTFE of the virgin material is added to the resin composition. And does not hinder injection moldability. The recycled PTFE powder has an average particle size of 1 to 1.
Since it is fired once at a thickness of 50 μm, preferably 3 to 30 μm, it is an additive that can provide a stable molded product without any dimensional change, shape change or cracking of a resin molded product mixed with this.

The perfluoro-based fluororesin has a structure in which all or all of the carbon atoms constituting the skeleton molecular chain are surrounded by fluorine atoms by incorporating a small amount of oxygen atoms. Fluorine resin has the highest heat resistance and excellent properties such as coefficient of friction, non-adhesion, oil resistance, and chemical resistance among fluorinated resins. For example, PTFE resin which is a raw material of recycled PTFE powder Is mentioned. The thermal decomposition temperature of the PTFE resin is 508 to 5
It is 38 ° C, and has excellent heat resistance.

The blending ratio of the above-mentioned recycled PTFE powder and other perfluoro fluororesins in the total composition is preferably 2 to 25% by weight. If it is less than 2% by weight, the sliding properties of the resin composition will not be improved, and the problem of damage to the sliding partner cannot be solved. If the amount is more than 25% by weight, there is a problem that the moldability is deteriorated. It is also conceivable that a molybdenum compound such as molybdenum disulfide may play an auxiliary role in improving the sliding characteristics similarly to the fluorine-based resin.

[0044]

EXAMPLE A polyetheretherketone resin (PEEK), which is a kind of polyetherketone resin excellent in heat resistance, mechanical properties, etc., is used as a main material (to prevent the compounding ratio from being less than 50% by weight). , Average fiber diameter 5-20μ
m, a pitch-based carbon fiber (CF) 5 having an average fiber length of 10 to 500 μm and moderate strength, elastic modulus and hardness.
Polytetrafluoroethylene (PTFE), talc, mica, calcium carbonate, molybdenum disulfide, molybdenum disulfide, -100%, preferably 1-70 μm, average particle size of 摺 動 25% by weight, sliding property, releasability and dispersibility Raw materials including 5 to 35% by weight of a solid lubricant such as tungsten as a filler material are dry-mixed using a mixer, melt-extruded with an extruder, granulated, and then injected with an injection molding machine. Injection pressure 80 ~ 120MPa, cylinder temperature 320 ~
Under a condition of 420 ° C. and a mold temperature of 160 to 200 ° C., injection molding is performed by defining a predetermined size and shape so that a longitudinal section becomes substantially rectangular, and then heat-treated at 180 to 280 ° C., and dimension measurement, and A bending strength test was performed.

In the injection molding, the injection pressure is 20
-200 MPa, preferably within the range of 50-150 MPa, the cylinder temperature is controlled within the range of 250-450 ° C., the temperature around the nozzle is within the range of 300-500 ° C., and the mold temperature is set at 1
100 to 200 ° C, 120 to 20 on average in the cavity
It is preferable to control the temperature within the range of 0 ° C. and perform injection molding. If the injection pressure is too low, it is difficult to obtain a molded body having sufficient mechanical strength, which may cause voids and sink marks.If the injection pressure is too high, an excessive load is applied to the injection molding machine and the molded body, and warpage and molding may occur. This is because it is easy to cause separation failure. Further, if the cylinder temperature is too low, the thermoplastic resin does not melt sufficiently and causes a short shot, and if the cylinder temperature is too high, it tends to cause sink marks and mold release failure due to rapid cooling during cooling. The outer diameter (D) of the seal ring is 45 mm, the outer surface width (B) is 2 mm, and the wall pressure (T) is 2 m, which is mainly orthogonal to the outer surface width (B), by injection molding.
m seal ring was manufactured.

The materials used in the examples are as follows.

PEEK: 50% by weight (ICC UK)
Pitch CF: 20% by weight (Kureha Chemical: Kureha M2)
07S, average fiber diameter 14.5 μm) Recycled PTFE: 10% by weight (KT300 manufactured by Kitamura Co., Ltd.)
H, average particle size: 25 to 30 μm) Talc: 20% by weight (Matsumura Sangyo Co., Ltd .: crown talc average particle size: 11 μm) The synthetic resin used as the main material is PEEK.
In addition, polyphenylene sulfide resin (PPS),
Thermoplastic polyimide resin (TPI), polyamide imide resin (PAI), (all) aromatic liquid crystal polyester resin (LCP), and the like. The physical properties of the molded product containing PEEK as a main material were as follows. (Brackets indicate preferred test methods, but are not limited to these measurement methods.) Melting point: 330 to 340 ° C (ASTM D-2117, D
SC method) Thermal deformation temperature: 270 to 290 ° C. (ASTM D648
(1.81 MPa) Glass transition point: 140 to 150 ° C. Flexural strength: 120 to 130 MPa (ASTM D-79)
0) Flexural modulus: 9000 to 10000 MPa (ASTM)
D-790) Hardness (Rockwell hardness): M75 to M80 (ASTM)
D-785) Linear expansion coefficient: (1.6 to 3) × 10 ⁻⁵ / ° C. (TMA method) Heat treatment such as annealing heat treatment is performed at a temperature equal to or higher than the glass transition point of the binding heat-resistant resin material and the melting point of the molded material. It is preferable to carry out at a temperature within the range of less than, specifically, for example, as in the present embodiment, the glass transition point or higher, and the heat deformation temperature of 5 to 40 ° C.
The heating may be performed at a temperature not higher than 10 ° C., preferably at a temperature not higher than 10 ° C. and 30 ° C. If the heat treatment temperature is lower than the glass transition point, it will not be crystallized, or it will take a lot of time for the crystallization to proceed, and the efficiency will be poor. Difficult to get. If the heat treatment temperature is equal to or higher than the melting point or exceeds the above-mentioned temperature, the heat resistant binder resin is melted or remarkably softened, so that it cannot be formed as a seal ring-shaped molded product or it is difficult to maintain dimensional accuracy.

The surface shape and surface roughness of the sliding surface of the oil seal ring and its mating die surface or the mating material that slides tightly are defined as the maximum roughness (Rmax) and the arithmetic average roughness (Rmax). According to an evaluation method defined by JIS, such as Ra) and ten-point average roughness (Rz), if it is about 0.1 to 25 μm, preferably about 0.1 to 10 μm, it has excellent slidability and mold releasability. It will be. The surface of the manufactured seal ring had an arithmetic average roughness (Ra) of 0.1 to 3.2 μm.

The molded product (3) obtained by the injection molding described above
0 ′) is at the abutment (38i, 38) as shown in FIG.
j) are separated from each other and have no radial overlap between them. Then, as shown in FIG. 8, using a jig (40) composed of a cylindrical body (42) made of synthetic resin or rubber and a ring gauge (44), the above molded product (30 ′) is attached to a ring gauge ( 44)
The cylindrical body (42) is adjusted and inserted into a state having a small clearance (loose fit) inside the molded product (30 '). By having the minute clearance, the setting when the seal ring molded product (30 ') is mounted on the jig before and after the heat treatment becomes easy. The ring gauge (44) is, for example, HRC20 to 60 in Rockwell hardness (C scale), and HRC4 in a heat-treated product such as quenching.
The surface roughness of the inner peripheral surface is the same as described above (0 to 60).
01 to 3.2S (Ra)). In addition, axis (2)
Are about the same hardness. The resin constituting the columnar body (42) is a substance having a larger coefficient of thermal expansion than the ring gauge (44), for example, a resin or a polymer substance such as an elastomer having a larger coefficient of thermal expansion than the ring gauge (44). Forcible force is applied from the inside of the molded product (30 ') by thermal expansion. Rubber hardness (Hs) for elastomeric polymers
Is about 60 to 100, preferably about 65 to 90, and it is considered preferable to obtain good elastic forcing. If the rubber strength is too high, the molded product (3
It is difficult to insert the cylindrical body (42) inside 0 ′), and if the rubber hardness is too low, it is too soft, so that it is difficult to obtain an appropriate elastic force.

In the present invention, the cylindrical body (42) is mainly composed of PTFE as a fluorine-based resin having excellent heat resistance and non-adhesiveness. In order to improve heat deformation resistance and creep resistance, glass fiber or carbon fiber is used. A resin composition containing the same filler (about 5 to 30% by weight) as the filler, including fibers, graphite, aromatic polyimide resin powder and the like, was used. The linear expansion coefficient of the cylindrical body (42) made of such a composition is about (5 to 50) × 10 ⁻⁵ / ° C., and the linear expansion coefficient of the seal ring molded product (30 ′) made of the composition is obtained. (1.6-3) × 10 ⁻⁵ / ° C. and the coefficient of linear expansion of the metal ring gauge (44) (about 1-3) × 10 ⁻⁵ / ° C.
Therefore, the outer peripheral surface (32) of the seal ring molded product (30 ') is pressed against the inner peripheral surface of the ring gauge (44), and the outer peripheral surface of the seal ring molded product (30') is Within the range of the gradient of. Such a heat treatment temperature is adjusted to about 200 to 300 ° C. in PEEK. Since the cylindrical body (42) is excellent in non-adhesiveness and mainly composed of PTFE having a large coefficient of thermal expansion, the cylindrical body (42) and the seal ring molded product (3) during the high-temperature heat treatment.
0 ′) is not fused.

As described above, the entire jig (40) including the molded product (30 ') is put into an electric furnace or the like, and the molded product (3) is placed.
0 ′) above the glass transition point of the base resin, for example PE
In EK, the molded product (30 ') is heated and set to a temperature of about 140 ° C. or more to perform heat fixing. Thus, a composite step-cut type seal ring (30) as described above, which is a final product, is obtained.

In the structure shown in FIGS. 1A and 1B, the material of the cylinder (10) as the stationary member is an aluminum alloy for die casting (ADC12), and the material of the shaft (20) as the rotating member is carbon steel (S45C). , The sliding surface roughness of both was 3.2S (3.2R).
a) In the following, a test was conducted by changing the rotation behavior of the seal ring (30) by changing the gradient (Δθ) of its outer peripheral surface. FIG. 4 shows the result, in which the vertical axis represents the relative rotation ratio between the cylinder and the seal ring, and the horizontal axis represents the gradient (Δθ). As can be seen from the test results shown, the slope (Δ
Until θ) is about 1 °, the seal ring hardly rotates, but when the gradient (Δθ) exceeds about 1 °, the rotation ratio sharply increases and the seal ring starts rotating with the shaft. In other words, when the slope exceeds about 1 °, the seal ring rotates relative to the cylinder. In addition, as shown in FIG. 1C, the outer peripheral surface of the seal ring has a reverse gradient, that is, a gradient (downward gradient) toward an end surface (back pressure receiving surface) on the side (back pressure side) not receiving the action of hydraulic pressure. -Δθ), hydraulic pressure does not enter between the seal ring and the cylinder, so that the seal ring and the cylinder do not rotate relative to each other. Further, if the inclination is within the range of the predetermined angle, the seal ring can be incorporated into the shaft groove regardless of the hydraulic pressure side and the back pressure side, which is advantageous in terms of ease of assembling and handling of the seal ring.

FIG. 5 shows the leakage amount when the shaft (rotation speed: 8000 rpm, oil pressure: 1.0 MPa) was operated for 100 hours for each of the above embodiment (FIG. 1) and a comparative example of the conventional cast iron seal ring. In the graph, the vertical axis represents the leak amount (ml / min), and the horizontal axis represents the temperature (° C.).
In the case of the embodiment, the leak amount hardly changes, whereas in the case of the comparative example, the leak amount is large from the beginning of rotation, and further increases as the temperature rises. This means that when the oil enters between the seal ring and the cylinder, hydraulic pressure acts on the outer peripheral surface of the seal ring and the seal ring is relatively rotated. The fact that the abrasion of the cylinder is 5 μm or less in the example but 40 to 50 μm in the comparative example also supports this.

[0054]

As described above, the seal ring for a rotating body of the present invention is a seal ring that is injection-molded from a synthetic resin and is endless and expandable and contractable. In order to seal between the shaft and the shaft which can be accommodated as possible, it is arranged in an annular groove formed in the shaft, and the gradient of the outer peripheral surface which comes into contact with the cylinder when the diameter is expanded by fluid pressure is set to ± 1 ° or less. Therefore, relative rotation with the cylinder hardly occurs, and damage to the soft counterpart material can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing an embodiment.

FIG. 2 is a schematic longitudinal sectional view showing a modified example.

FIG. 3 is a schematic longitudinal sectional view showing a comparative example.

FIG. 4 is a graph showing a relationship between a gradient and a ring rotation ratio.

FIG. 5 is a graph showing test results regarding the amount of leakage.

FIG. 6 is an enlarged front view of an abutting portion of a seal ring (a),
Enlarged plan view (b) and enlarged perspective view (c)

FIG. 7 is an enlarged front view (a) and an enlarged plan view (b) of an abutment portion in a molded product.

FIG. 8 is a sectional view of a heat fixing jig accommodating a molded product.

FIG. 9 is a longitudinal sectional view of a sealing device equipped with a sealing ring.

FIG. 10 is an enlarged view of a seal ring portion in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cylinder 20 Shaft 30 Seal ring 30 'Molded product 32 Outer peripheral surface 32a, 32b Depression 34a End surface (pressure receiving surface) 34b End surface (anti-pressure receiving surface) 36 Inner peripheral surface 38i, 38j Abutment 40 Heat fixing jig

Claims (5)

[Claims] 1. A seal ring, which is injection-molded from a synthetic resin and is endlessly expandable and contractable, wherein a seal is provided between a cylinder and a shaft rotatably housed in the cylinder. A seal ring for a rotating body, which is arranged in the formed annular groove and has a gradient of ± 1 ° or less on an outer peripheral surface that comes into contact with the cylinder when the diameter is expanded by fluid pressure. 2. The seal ring for a rotating body according to claim 1, wherein the cross-sectional shape of the outer peripheral surface is concave. 3. The seal according to claim 1, wherein the hardness is HRM70 or more. 4. The method according to claim 1, wherein the synthetic resin is one synthetic resin selected from the group consisting of an aromatic polyetherketone resin, a polyarylene sulfide resin, an aromatic polyimide resin, and a polyamideimide resin. Claim 1
Or 2) a seal ring for a rotating body. 5. The seal ring for a rotating body according to claim 1, wherein the seal ring is manufactured by heat setting after injection molding.