JP4515048B2 - Rotating shaft seal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary shaft seal, and more particularly to a rotary shaft seal used to seal a high-pressure fluid such as gas.
[0002]
[Prior art]
Conventionally, a rotating shaft seal 31 as shown in FIGS. 2C and 3C is known (see, for example, Patent Document 1). The general configuration of the conventional rotary shaft seal 31 was as follows. In other words, a sliding contact portion S ₀ slidably contacting the surface of the rotating shaft 32 is provided at the distal end portion 33a of the lip 33 of the rubber seal portion, and the shape of the lip 33 is substantially L-shaped from the outer case 34 to the sealed fluid side C. It was the cross-sectional shape extended | stretched in the shape. The rotary shaft seal 31 interposed between the rotary shaft 32 and the casing (not shown) surrounds the inner flange 36 of the outer case 34 and is integrated by adhesion or baking. comprising a part, the cross-sectional plane L-shaped rear support bracket 38, a rubber sealing portion of the lip 33, (from behind) from the low pressure side and the inner peripheral surface side and supports.
Conventionally, in this type of rotating shaft seal, the tip 33a of the lip 33 --- sliding contact portion S ₀ --- is brought into sliding contact with the rotating shaft 32 evenly in the circumferential direction. Efforts have been made in design and manufacturing. Therefore, it has been considered that the cylindrical support portion 38a of the back support metal fitting 38 is formed of a smooth cylindrical wall portion and has an accurate circular cross section.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-97723
[Problems to be solved by the invention]
When a high pressure is applied to the sealed fluid chamber 39, as shown in FIG. 3C, the lip tip portion 33a (sliding contact portion S ₀ ) has a large contact surface pressure P with respect to the rotating shaft 32 and has a full circumference (360 °). Contact evenly over. This makes it difficult for the lubricating oil in the sealing fluid to enter (introduce) the interface between the rotary shaft 32 and the sliding contact portion S _0, and promote wear of the lip tip portion 33 a (sliding contact portion S ₀ ). The sliding contact portion S ₀ is worn away, and the sealing performance (sealability) is abruptly deteriorated to cause external leakage of fluid. In other words, in a high-pressure environment, the tip 33a of the rubber lip 33 is pressed strongly against the rotating shaft 32 and is uniformly pressed over the entire circumference of the rotating shaft 32. Lubricating oil cannot enter the interface between the sliding contact portion S ₀ and the rotary shaft 32, increasing the frictional resistance and generating heat, resulting in a problem that the sliding contact portion S ₀ wears out early. It was.
[0005]
[Means for Solving the Problems]
Accordingly, the present invention is supported, the rubber sealing portion having an axis-orthogonal wall portion having the sliding portion in contact with the surface of the rotating shaft on the inner peripheral edge, and, the shaft center-orthogonal wall portion from the low-pressure side And a rubber that is compressed by receiving pressure, wherein the axially orthogonal wall portion of the rubber seal portion forms an annular groove on the back side corresponding to the support bracket. The annular groove is configured to block and / or absorb the flow in the inner diameter direction, and at least one of the depth dimension, the width dimension, and the radial position of the annular groove is circumferential. The contact surface pressure on the surface of the rotating shaft of the sliding contact portion is configured to be uneven in the circumferential direction.
Alternatively, a back support metal fitting having a rubber seal portion having a sliding contact portion in contact with the surface of the rotating shaft at a tip portion of the lip, and a cylindrical support portion supporting the lip of the rubber seal portion from the inner peripheral surface side. and comprising, further, the cross-sectional shape of the tubular support portion of the rear support brackets as polygonal shape, the contact surface pressure to the surface of the rotary shaft of the sliding contact portion of the tip portion of the lip circumferential direction It is configured to be non-uniform.
Alternatively, a back support metal fitting having a rubber seal portion having a sliding contact portion in contact with the surface of the rotating shaft at a tip portion of the lip, and a cylindrical support portion supporting the lip of the rubber seal portion from the inner peripheral surface side. Furthermore, the cross-sectional shape of the cylindrical support portion of the back support metal fitting is an uneven corrugated annular shape, and the contact surface pressure to the surface of the rotating shaft of the sliding contact portion of the tip end portion of the lip is set in the circumferential direction. It is configured to be non-uniform.
Alternatively, a back support metal fitting having a rubber seal portion having a sliding contact portion in contact with the surface of the rotating shaft at a tip portion of the lip, and a cylindrical support portion supporting the lip of the rubber seal portion from the inner peripheral surface side. Further, the cross-sectional shape of the cylindrical support portion of the back support metal fitting is made an annular shape with an uneven step, and the contact surface pressure to the surface of the rotating shaft of the sliding contact portion of the tip portion of the lip is measured. It is configured to be unequal in the direction.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
FIG. 1 shows an embodiment of the present invention, FIG. 1 (A) shows a longitudinal section of the main part, and FIG. 1 (B) is a simplified configuration explanatory view of the main part viewed from the direction of the axis L. The rotary shaft seal, for example, seals a fluid such as a high-pressure refrigerant on the sealed fluid chamber 21 side. In FIG. 1A, only a half of the cross section of the rotary shaft seal is shown, and the solid line indicates The free state --- not-mounted state-- is shown, and the rotating shaft 20 and the housing (casing) 22 are indicated by a two-dot chain line. In the mounted state interposed between the rotating shaft 20 and the housing 22, each part is elastically deformed.
[0007]
In FIG. 1, reference numeral 1 denotes a metal outer case having inner flange portions 2 and 3, and the outer peripheral surface of the cylindrical wall portion 4 of the outer case 1 and the sealing fluid side C (sealing fluid chamber 21 side). The rubber seal portions 5 are fixed and held integrally on both the front and rear surfaces of the inner collar portion 2 by adhesion, welding, baking, or the like. Further, a seal element 7 with a spiral groove 6 is provided on the anti-sealing fluid side (low pressure side / atmosphere side) Z from the seal portion 5. The material of the seal element 7 is preferably a fluorine resin such as PTFE.
[0008]
Reference numeral 8 denotes a support fitting having an I-shaped cross section. That is, the annular flat plate-like support fitting 8 is fitted so that the outer peripheral edge 8 a is in contact with the inner peripheral surface of the cylindrical wall portion 4 of the outer case 1. The support metal fitting 8, the first inner case 9, the second inner case 10, the sealing element 7, and the inner member 11 are sequentially held and fixed between the inner flange portions 2 and 3.
[0009]
The rubber seal portion 5 fixed integrally to the outer case 1 is a cylinder having an outer peripheral surface formed in a corrugated corrugated shape (in a free state) for elastically contacting the inner peripheral surface of the housing 22 to form a sealing action. An axial center orthogonal part having an inner cover part having a U-shaped cross section covering the front and rear surfaces of the inner cover part 2 and the inner cover part 2 extending in the inner diameter direction and having a sliding contact part 23 on the inner peripheral edge. And a wall portion 5b.
[0010]
That is, the rubber seal part 5 is provided with a shaft center orthogonal wall part 5b orthogonal to the axis L of the rotation shaft 20 (rotation shaft seal), and the inner peripheral edge of the shaft center orthogonal wall part 5b is round ( A slidable contact portion 23 having a rounded portion is formed. An annular flat plate-like support fitting 8 orthogonal to the shaft center L supports (pressure contact) the shaft center orthogonal wall portion 5b from the low pressure side --- the anti-sealing fluid side Z--.
Moreover, the axially orthogonal wall portion 5b of the rubber seal portion 5 has an annular groove 24 on the back side corresponding to (press contact) with the support fitting 8. FIG. 1B is a rear view (viewed from the direction of the axis L) showing an example of the annular groove 24.
[0011]
As will be described later, the annular concave groove 24 absorbs and / or absorbs the flow of the rubber whose axial center orthogonal wall portion 5b is compressed by receiving pressure in the inner diameter direction, that is, in the radial direction. Cut off.
In other words, the outer case 1 has the inner flange portion 2 at the inner end portion of the sealed fluid side C, and the sliding contact portion 23 is disposed on the axis orthogonal plane P ₀ including the inner flange portion 2. .
That is, since the inner flange portion 2 has a (small) thickness, the axial center orthogonal plane P ₀ is shifted in the axial direction by the (small) thickness, and there are only a plurality of them. The axial direction position of the sliding contact portion 23 is disposed on at least one orthogonal plane P ₀ . The axial direction position of the slidable contact portion 23 is defined to indicate the center of gravity position G (see FIG. 3A) of the contact pressure P at the portion slidably contacting the rotating shaft 20 at the maximum operating pressure.
[0012]
Although not shown in the drawings, it is also preferable to arrange the axial direction position of the sliding contact portion 23 in the vicinity of the axial center orthogonal plane P ₀ (not shown). Here, the vicinity means the uneven distribution of not more than 5 times the thickness of the inner flange portion 2.
Alternatively, it can be paraphrased that the axial position of the sliding contact portion 23 is disposed within the axial width dimension M of the outer case 1. However, in the present invention, the axial width dimension M is defined as a dimension including (plus) the thickness T ₁₇ of the rubber coating layer 17 on the sealed fluid side C covering the inner flange portion 2. With such a configuration, there is no portion to which the pressure from the sealed fluid side C is applied on the radially outer side of the center of gravity position G of the contact pressure (surface pressure) P distribution when the sliding contact portion 23 receives pressure. This point becomes clear when FIG. 3A is compared with the conventional FIG.
[0013]
Next, one major feature of the present invention will be described. In FIGS. 1A, 1B, 2A, 2B and 3A, 3B, the annular groove 24 is set so that its depth dimension changes in the circumferential direction. Thus, the contact surface pressure P to the surface of the rotating shaft 20 of the sliding contact portion 23 is set to be non-uniform in the circumferential direction. In FIG. 1A, a solid line indicates a shallow (small) portion D ₁ having a depth dimension of the concave groove 24, and a broken line indicates a deep (large) portion D ₂ having a depth dimension. In the example of FIG. 1 (B), shallow portions D ₁ , D ₁ , D ₁ with a central angle α of about 60 ° and a deep portion D ₂ , with a central angle β of about 60 ° and a deep size. A case where D ₂ and D ₂ are alternately arranged will be exemplified. Incidentally, setting the alpha> beta, or conversely, alpha <are also possible to set as beta, FIG 3 (B) of such deep site D ₂ in the contact pressure P of depth is small The lubricating oil in the fluid can be easily introduced and can spread over the entire circumference of the sliding contact portion 23, thereby suppressing rubber wear.
[0014]
Incidentally, in FIGS. 1 and 2A and 2B, the shape of the axial center orthogonal wall portion 5b of the rubber seal portion 5 will be additionally described. In a free state (non-mounted state), the sliding contact portion 23 is It has a circular arc shape, and continues to the contact portion with the support fitting 8 while maintaining the circular arc shape. However, the sealing fluid side C has a protruding portion 13 formed to protrude like a bird cage (triangular mountain shape).
In other words, most of the end surface 14 on the side of the sealed fluid chamber 21 of the axial center orthogonal wall 5b is a flat surface (planar), but in the vicinity of the sliding contact portion 23, it has a bird cage shape (triangular mountain shape). It has a protruding portion 13 that protrudes.
[0015]
When the slidable contact portion 23 is worn by sliding with the rotary shaft 20, it is provided so that rubber is sent (newly) from the protruding portion 13 under fluid pressure. That is, even when worn, the rubber is newly supplied from the protruding portion 13 so that the rotating shaft 20 and the slidable contact portion 23 are kept in a slidable contact state, and the sealing performance can be maintained.
[0016]
2 and 3 are arranged with the main part of the embodiment shown in FIG. 1 and the main part of the conventional example as (A), (B), and (C), respectively. 2 is a diagram for comparison in a free state, and FIG. 3 is a diagram for comparison in a pressure receiving (use) state in which fluid pressure is applied. 2 (A) and 3 (A) are cross-sections of the shallow portion D _{1 having} a depth dimension of the annular groove 24, and FIGS. 2 (B) and 3 (B) are views of the deep portion D ₂ . FIG. 2C and FIG. 3C show a conventional example.
[0017]
As apparent from FIGS. 2 and 3, the embodiment of the present invention shown in FIG. 1 has a cylindrical extending portion 33c (parallel to the axis L) and a cylindrical support portion 38a. However, when high-pressure gas pressure such as CO ₂ gas is applied (during pressure reception), the influence of the pressure does not directly affect the sliding contact portion 23 (does not affect). Therefore, as shown in the contact surface pressure distribution graph 15 shown in FIG. 3 (C), the conventional seal generates a large surface pressure, whereas the contact surface pressure distribution graph 15 shown in FIGS. 3 (A) and 3 (B). As described above, in the seal showing one embodiment of the present invention, the surface pressure is reduced and the distribution is also gentle. In FIG. 3, a two-dot chain line indicates a free state, and a solid line indicates a pressure receiving time when a fluid pressure of 6 MPa is applied.
[0018]
When the contact surface pressure was analyzed using FEM, when the fluid pressure was 6 MPa, the maximum contact surface pressure reached about 11 MPa in the conventional example of FIG. In A), about 8 MPa and about 3 MPa can be reduced. And in FIG. 3 (B), it is about 5 MPa. Although not shown, when the internal stress distribution of the rubber is analyzed by the FEM analysis, the high stress region is concentrated around the concave groove 24, but the absolute value is small in the vicinity of the sliding contact portion 23, and It was found to be distributed over a wide area. (In contrast, in the conventional example of FIG. 3 (C), the high stress region to the sliding portion S ₀ are concentrated.)
[0019]
Rotating shaft seal according to an embodiment of the present invention (and another embodiment of FIGS. 5 to 7 described later) shown in FIGS. 1 and 2A, 3B and 3A, 3B. The operation (operation) of is different from the conventional example (FIG. 3C) in that the contact surface pressure is obtained by a self-sealing effect like a general O-ring. That is, in the conventional example, the fluid pressure inward in the radial direction is directly applied to the lip tip 33a extending (largely) to the sealed fluid side C, and the pressing force due to the rubber flow in the direction of arrow F is also added. The sliding contact portion S ₀ has increased the contact surface pressure P. However, in the seal according to the embodiment of the present invention, the fluid pressure first acts on the end surface 14 of the axial center orthogonal wall portion 5b. Since the direction of the action is a direction parallel to the shaft center L, it acts as a compressive force pressed against the support member 8 orthogonal to the shaft center, and the rubber moves inward in the radial direction while being compressed and deformed. Depresses part 23 ─── indirectly ─── and exerts sealing power (sealing performance). The action (operation) corresponding to the self-sealing effect of the so-called O-ring is shown. In this way, it is possible to prevent an excessively strong pressing force from being applied. As shown in the contact surface pressure distribution diagrams 15 of FIGS. Desirable improvement in durability can be achieved.
[0020]
In addition, by having the concave groove 24, it absorbs the rubber that moves inward in the radial direction (the concave groove 24 is reduced from the two-dot chain line to the solid line) and / or radially inward. The movement is blocked, and the influence on the increase of the contact surface pressure on the sliding contact portion 23 is reduced.
[0021]
The effect of the concave groove 24 is apparent in FIG. In FIG. 4, (A) shows a case with a concave groove 24 (corresponding to FIG. 1), and (B) shows a comparative example without a concave groove 24. The contact surface pressure was analyzed using FEM analysis. A contact pressure distribution graph 15 was drawn. FIG. 4 shows the case where the fluid pressure is 6 MPa. In the comparative example, when the fluid pressure is zero, the maximum contact surface pressure P is 3 MPa or more when there is no concave groove 24 when the tightening allowance is 0.6 mm. Is also reduced. When a fluid pressure of 6 MPa is applied (pressure load state), the maximum contact surface pressure P is 9.6 MPa in the comparative example of FIG. 4B, whereas 8.5 MPa in FIG. 4A is about 1 MPa. Is also low.
[0022]
Next, FIG. 5 shows another embodiment. 5A is a longitudinal sectional view of the main part, and FIG. 5B is a rear view of the annular groove 24 viewed from a direction parallel to the axis L, and the diameter of the annular groove 24 is shown in FIG. The direction position is alternately changed for each predetermined central angle α, β.
That is, in FIG. 5A, the same reference numerals are the same as those in FIG. 1A, but the differences are as follows. That is, the solid line is the arc part D ₃ where the radial position of the concave groove 24 is close to the axis L, and the broken line is the arc part D ₄ where the radial position of the concave groove 24 is far from the axis L. D ₃ and D ₄ are alternately arranged, for example, with respective central angles α and β of about 60 °. In other words, the arc portion D ₃ with the central angle α has a small radius from the axial center point, and the circular arc portion D _{4 with the} central angle β is indicated by hatching in FIG. 5B. The radius from the point is large. Both arc portions D ₃ and D ₄ communicate with each other through a step portion to form a groove 24 in an annular shape as a whole. It should be noted that it is free to set each of the arc portions D ₃ and D ₄ to four or more, set α> β, or set α <β. In Figure 5 the arc portion D ₃ in the radial dimension from the axis point is smaller as (B), small contact surface pressure P of the sliding portion 23, the lubricating oil is easily introduced in the fluid, the sliding portion 23 total The wear of rubber can be suppressed by spreading around the circumference.
[0023]
As described above, in the embodiment of FIG. 5, the annular groove 24 changes its radial position in the circumferential direction, and the contact surface pressure P to the surface of the rotary shaft 20 of the sliding contact portion 23 is not circumferentially changed. configured so that uniform (heterogeneous) of low contact surface pressure portion (arc portion D ₃ corresponding position), and easy to introduce lubricating oil, the entire circumference sliding portion 23, the rotary shaft 20 With the rotation of the oil, the lubricating oil is distributed, the generation of frictional heat is suppressed, the early wear is prevented, and durability is improved.
[0024]
Next, FIGS. 6A and 6B show different embodiments, and correspond to FIGS. 1B and 5B described above. That is, in FIG. 6A, when viewed from the direction parallel to the axis L, the annular groove 24 is formed in a polygonal shape such as a hexagon (increase / decrease in the number of corners). In this configuration, the radial position—the distance dimension from the axial center point to each point of the concave groove 24—changes in the circumferential direction. Further, in FIG. 6B, when viewed from the direction parallel to the axis L, the annular groove 24 is a shape drawn in a concavo-convex shape based on a basic circle figure, for example, flower shape or roundness. It is a gear type, etc., with a configuration in which the radial position of the groove 24-the distance from the axial center point to each point of the groove 24-is smoothly changed in the circumferential direction. is there.
[0025]
As described above, in the embodiment shown in FIG. 6A or 6B, the annular groove 24 has a shape in which the radial position thereof changes in the circumferential direction, and the sliding contact portion 23 is formed on the surface of the rotating shaft. The contact surface pressure P is configured to be non-uniform (non-uniform) in the circumferential direction, and the position where the contact surface pressure is low (the intermediate portion of each side of FIG. 6A or the vicinity of the valley bottom of FIG. 6B) Lubricating oil is introduced from the part), and the lubricating oil is spread over the entire circumference of the sliding contact portion (with rotation of the rotating shaft) to prevent premature wear and improve durability. In addition, increase / decrease in the number of sides of the polygon in FIG. 6A and increase / decrease in the number of peaks and valleys in FIG. 6B can be freely set.
[0026]
Next, FIG. 7 shows still another embodiment. It is a figure corresponding to FIG. 1 mentioned above. That is, in FIG. 7A, the same reference numerals are the same as those in FIG. 1A, but the differences are as follows. That is, the solid line is the circular arc portion D ₅ where the width dimension of the concave groove 24 is small, and the broken line is the circular arc portion D ₆ where the width dimension is large, as shown in FIG. 7B, both arc portions D ₅ , D For example, ₆ are alternately arranged with respective central angles α and β of about 60 °. Note that it is free to set each of the arc portions D ₅ and D ₆ to four or more, set α> β, or set α <β. In FIG. 7B, the arc portion D ₆ having a large width dimension is indicated by being hatched.
[0027]
As described above, in the embodiment shown in FIGS. 7A and 7B, the width of the annular groove 24 increases and decreases (as it goes in the circumferential direction), and the contact surface pressure P is uneven in the circumferential direction. (Non-uniform), introducing the lubricating oil from the portion having a low contact surface pressure (arc portion D _{6 having} a large width), and spreading the lubricating oil over the entire circumference of the sliding contact portion 23, Prevents early wear and improves durability.
[0028]
By the way, it is also preferable to combine the above-described embodiments (FIGS. 1, 5, 6 and 7). For example, both the depth and radial position of the concave groove 24 are changed in the circumferential direction, or the depth and width dimension of the concave groove 24 are changed in the circumferential direction, or the width dimension of the concave groove 24 is changed. It is also desirable to change the radial position together in the circumferential direction (not shown).
[0029]
Next, in still another embodiment shown in FIG. 8, in the conventional example of FIG. 2 (C) and FIG. 3 (C), it has already been described with reference to FIG. 1, FIG. 5, FIG. This is an invention in which improvements are made so that the contact surface pressure P becomes uneven in the circumferential direction.
In the embodiment shown in the vertical cross-sectional view of the main part in FIG. 8A and the cross-sectional view in the main part in FIG. 8B, it is basically the same as FIG. 2C and FIG. In addition, a rubber seal portion 26 having a sliding contact portion S ₀ that contacts the surface of the rotating shaft 20 at the tip portion 33a of the lip 33 is provided, and the outer case 34 has a pair of inner flanges 36 and 37. The rubber seal portion 26 is integrally fixed to the outer case 34 by baking or bonding.
[0030]
Rear support bracket 28 for supporting the rubber sealing portion 26 from the rear side, a longitudinal L-shaped section, a cylindrical support portion 28a for supporting the inner peripheral surface of the lip 33 of the rubber sealing portion 26, the shaft And an orthogonal wall portion 28b orthogonal to the center L. And the cross-sectional shape of this cylindrical support part 28a is made non-uniform in the radial direction with respect to the (basic virtual) circle. That is, the cross-sectional shape of the tubular support portion 28a, as shown in FIG. 8 (B), the formed polygonal, the sliding portion S ₀ of the lip end portion 33a (to the surface of the rotary shaft 20) The contact surface pressure P is configured to be uneven in the circumferential direction. 8 (C) and 8 (D) show another embodiment corresponding to FIG. 8 (B). As shown in FIG. 8 (C), the cylindrical support portion 28a is formed in an uneven corrugated annular shape, As shown in FIG. 8D, it is formed in an annular shape with uneven steps. In any case, the contact surface pressure P to the surface of the rotating shaft 20 of the lip tip 33a is configured to be non-uniform (non-uniform) in the circumferential direction.
[0031]
Corner in FIG. 8 (B), the peak portions in FIG. 8 (C), the At a convexly curved portion in FIG. 8 (D), the to reduce the contact surface pressure of the sliding portion S ₀ (P), sliding Easy introduction (penetration) of the lubricating oil into the contact portion S ₀ , and with the rotation of the rotary shaft 20, the lubricating oil is spread over the entire circumference of the sliding contact portion S ₀ to prevent premature wear and durability Improves sex. In FIG. 8, reference numerals 7, 9, 10, 11 and the like are substantially the same as those in FIG.
[0032]
By the way, for each of the above-described embodiments of the present invention, the annular groove 24 of each form has a perfect circle shape, the same depth, and the same width shape, or the back support fitting 28 has a perfect circle shape, and a circular with a free state in (rather than a perfect circle) in the sliding portion 23, S ₀ itself irregularities waveform, upon insertion of the rotary shaft 20, a contact surface pressure P to the surface of the rotary shaft 20 circumferentially However, there is a problem in airtightness when the sealing fluid is at a low pressure or in a non-pressurized state.
[0033]
In addition, this invention is not limited to the above-mentioned embodiment, For example, it is set as the structure which attached the rubber lip part to the low voltage | pressure side separately from the rubber seal part 5, or two or more seal elements 7 On the contrary, the seal element 7 can be omitted, or the shape of the support fitting 8 or the number of the inner cases 9 and 10 and the inner member 11 can be changed or changed.
[0034]
1 (FIG. 2 (A) (B), FIG. 3 (A) (B)), FIG. 5, FIG. 6, and FIG. Since the pressing force does not act on the sliding contact portion 23, an excessive contact surface pressure P can be prevented, an appropriate value of the contact surface pressure P is maintained, and the lubrication state with the rotary shaft 20 is maintained well. Abrasion can be suppressed and good sealing performance (sealing performance) can be exhibited over a long period of time. It is particularly suitable for sealing high pressure gas. Furthermore, the axial dimension of the rotary shaft seal can be reduced to achieve compactness.
[0035]
【The invention's effect】
The present invention has the following remarkable effects by the above-described configuration.
(According to claim 1), the contact surface pressure P is made uneven in the circumferential direction, and lubricating oil is introduced and infiltrated between the sliding contact portion 23 and the rotary shaft 20 from the portion of the small contact surface pressure P. Thus, with rotation, the lubricating oil can be spread over the entire circumference of the sliding contact portion 23 to prevent generation of frictional heat, prevent early wear, and achieve a long life. In addition, there is an advantage that there is no problem of poor airtightness in the case where unevenness is provided on the sliding contact portion 23 itself.
[0036]
(According to claim 1 ), the support fitting 8 receives the pressure in the direction parallel to the axis L due to the fluid pressure, and moves the rubber radially inward to indirectly contact the sliding contact portion 23. Therefore, the contact surface pressure P of the sliding contact portion 23 with respect to the rotating shaft 20 can be reliably suppressed so as not to be excessive. Furthermore, the axial direction dimension of the entire rotary shaft seal can be surely reduced to achieve compactness.
Moreover, the contact surface pressure P is made uneven in the circumferential direction, and lubricating oil is introduced and infiltrated between the sliding contact portion 23 and the rotary shaft 20 from the portion of the small contact surface pressure P, and with rotation, Lubricating oil can be spread all around the sliding contact portion 23 to prevent generation of frictional heat, prevent premature wear, and achieve a long life. In addition, there is an advantage that there is no problem of poor airtightness in the case where unevenness is provided on the sliding contact portion 23 itself.
[0037]
(According to claim 2 or 3 or 4) if not suitable for high pressure as claimed in claim 1, even at quite high pressures, as unequal contact pressure P in the circumferential direction, the small contact surface Lubricating oil is applied to the sliding contact portion S ₀ from the portion of the pressure P. Between the rotary shaft 20 and the rotary shaft 20 and the sliding contact portion S _{0 as} it rotates. Lubricating oil can be spread all around, preventing the generation of frictional heat, preventing early wear, and extending the service life. And the sliding contact part S ₀ There is also an advantage that the problem of poor airtightness does not occur when unevenness is provided on itself. Moreover, it is only necessary to replace the conventional back support bracket 38 with the back support bracket 28 of the present invention among the components of the conventional product, so that the product can be easily switched.
[Brief description of the drawings]
1A and 1B are diagrams showing an embodiment of the present invention, in which FIG. 1A is a side sectional view of an essential part, and FIG.
FIG. 2 is an explanatory view for explaining an enlarged comparison of the shape of an embodiment of the present invention and a conventional example.
FIG. 3 is an explanatory diagram for comparing shapes and operations of the present invention and a conventional example.
FIG. 4 is an explanatory diagram for comparison between an embodiment of the present invention and a comparative example.
5A and 5B are diagrams showing another embodiment, in which FIG. 5A is a side cross-sectional view of the main part, and FIG. 5B is a rear view of the main part.
FIG. 6 is a main part rear view showing another embodiment of the present invention.
7A and 7B are diagrams showing still another embodiment of the present invention, in which FIG. 7A is a side sectional view of a main part, and FIG. 7B is a rear view of the main part.
FIGS. 8A and 8B are diagrams showing still another embodiment of the present invention, in which FIG. 8A is a side cross-sectional view of a main part, and FIGS.
[Explanation of symbols]
1 Outer case 5 Rubber seal 5b Axis center orthogonal wall 8 Support bracket
20 axis of rotation
23 Sliding part
24 Annular groove
26 Rubber seal
28 Rear support bracket
28a Tubular support
33 Lip
33a Tip part C Sealed fluid side L Shaft center P Contact surface pressure S ₀ Sliding part

Claims (4)

A rubber seal portion (5) having an axial orthogonal wall portion (5b) having a sliding contact portion (23) in contact with the surface of the rotating shaft (20) at the inner peripheral edge, and the axial orthogonal wall portion (5b) is provided with a shaft center orthogonal support bracket (8) that supports the low pressure side, and the shaft center orthogonal wall portion (5b) of the rubber seal portion (5 ) is the support bracket (8). An annular groove (24) is formed on the back side corresponding to the structure, and the flow in the inner diameter direction of the rubber compressed by pressure is blocked and / or absorbed by the annular groove (24), and , At least one of the depth dimension, the width dimension, and the radial position of the annular groove (24) is set so as to change in the circumferential direction, and the rotation shaft ( A rotary shaft seal characterized in that the contact surface pressure (P) to the surface of 20) is uneven in the circumferential direction. A rubber seal portion (26) having a sliding contact portion (S ₀ ) in contact with the surface of the rotating shaft (20) at the tip end portion (33a) of the lip (33 ), and a lip of the rubber seal portion (26) (33) comprises a back support fitting (28) having a cylindrical support portion (28a) for supporting the inner peripheral surface from the inner peripheral surface side ,
Furthermore, the cross-sectional shape of the cylindrical support portion (28a) of the back support fitting (28) is a polygonal shape, and the rotation shaft of the sliding contact portion (S ₀ ) of the tip portion (33a) of the lip (33) A rotary shaft seal characterized in that the contact surface pressure (P) to the surface of (20) is uneven in the circumferential direction. A rubber seal portion (26) having a sliding contact portion (S ₀ ) in contact with the surface of the rotating shaft (20) at the tip end portion (33a) of the lip (33), and a lip of the rubber seal portion (26) (33) comprises a back support fitting (28) having a cylindrical support portion (28a) for supporting the inner peripheral surface from the inner peripheral surface side,
Further, the cylindrical support portion of the rear support brackets (28) the cross-sectional shape of (28a) as uneven wave ring-like, above the tip of the lip (33) sliding contact portion (33a) (S ₀₎ A rotary shaft seal characterized in that the contact surface pressure (P) to the surface of the rotary shaft (20) is uneven in the circumferential direction. Sliding contact portion (S) that contacts the surface of the rotating shaft (20) ₀  ) At the tip end (33a) of the lip (33), and a cylindrical support portion for supporting the lip (33) of the rubber seal (26) from the inner peripheral surface side ( A back support bracket (28) having 28a),
  Furthermore, the cross-sectional shape of the cylindrical support portion (28a) of the back support fitting (28) is an annular shape with an uneven step, and the sliding contact portion (S of the tip portion (33a) of the lip (33) (S ₀  The rotary shaft seal is characterized in that the contact surface pressure (P) to the surface of the rotary shaft (20) is uneven in the circumferential direction.

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