JP2929062B2 - Rotary shaft seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary shaft seal.

[0002]

2. Description of the Related Art Generally, in a compressor for a car air conditioner, a sealed fluid is a refrigerant (a gas or a liquid dissolved in an oil or the like) and a refrigerating machine oil, and is maintained at a predetermined pressure.
Therefore, it is necessary to prevent fluid leakage when the rotating shaft is stationary and when rotating.

Therefore, a rotary shaft seal as shown in FIG. 4 has been developed. The rotating shaft seal includes a first holding bracket a,
A first seal element b of a rubber elastic body, which is coated and integrated on the first holding metal member a, a second holding metal member c, and a second holding metal member c and the first seal element b by the caulking d of the first holding metal member a. A second sealing element e made of a synthetic resin sandwiched therebetween.

The first seal element b is brought into close contact with the hole of the housing f to prevent leakage of the fluid h from the housing f side, and the first seal element b is brought into contact with the outer peripheral surface of the rotary shaft g to rotate the rotary shaft. axis of rotation g at rest of g
Fluid h leaks from the side.

Further, the second seal element e is brought into contact with the outer peripheral surface of the rotating shaft g to prevent the fluid h from leaking from the rotating shaft g when the rotating shaft g is stationary and rotating.

Further, the flat plate portion i of the first seal element b and the annular flat plate outer peripheral edge j of the second seal element e are brought into close contact with a predetermined contact surface pressure by caulking d, so that the first seal element b and the first seal element b are brought into close contact. Fluid h leakage between the two seal elements e (so-called internal leakage indicated by small arrows in FIG. 4) is prevented.

[0007]

However, the annular flat plate portion i of the first seal element b and the annular outer peripheral edge j of the second seal element e have a flat surface in a free state before assembly. ) In the assembled state, the flat surfaces come into contact with each other. Therefore, the contact surface pressure distribution becomes flat.
Therefore, caulking d is insufficient and the first sealing element b
When the contact surface pressure between the annular flat plate portion i and the annular outer peripheral edge portion j of the second seal element e decreases, as shown by the small arrow in FIG. There is a possibility that the seal element e rotates together with the rotation axis g.

Accordingly, an object of the present invention is to provide a rotary shaft seal that can prevent internal leakage, stabilize sealing performance, and prevent co-rotation of the second seal element with the rotary shaft.

[0009]

In order to achieve the above-mentioned object, a rotary shaft seal according to the present invention comprises: an outer peripheral surface of an annular first holding metal fitting having an inner flange portion at one end edge; A first seal element made of a rubber elastic material is coated on the surface of the first seal element, and an end face of the annular flat plate portion of the first seal element, which is coated on the inner end face of the inner flange, is provided with a second synthetic resin material. One end surface of the annular plate-shaped outer peripheral edge of the seal element is brought into contact with the other end surface of the outer peripheral edge of the second seal element in the direction of the flat plate portion of the first seal element with a second holding metal. Pressing, the rotary shaft seal sandwiching the second seal element, in the state before assembly by the sandwiching, on the end face of the flat plate portion of the first seal element,
An annular small convex portion protruding outward from the end face is formed , and the flat portion of the flat plate portion is formed along a mountain skirt on the inner diameter side of the small convex portion.
Forming an inner small recess recessed inward from the end face , and along the outer diameter side of the small protrusion , the end face of the flat plate portion
The outer small concave part which dented inward was formed.

[0010]

When the second holding member is pressed in the direction of the flat plate portion of the first sealing element by caulking the first holding member or the like, one end surface of the outer peripheral portion of the second sealing element is brought into contact with the first sealing element. The end surface of the flat plate portion is brought into close contact with a predetermined contact surface pressure, and the small convex portion of the flat plate portion is compressed, so that the contact surface pressure distribution between the end surface of the flat plate portion and one end surface of the outer peripheral edge is small. In the contact portion corresponding to the portion, the height is further higher than in the contact portion between flat surfaces other than the small convex portion.

[0011] Therefore, the caulking or the like is insufficient, and the contact surface pressure between the one end face of the outer peripheral edge portion of the second seal element and the end face of the flat plate portion of the first seal element is reduced as a whole. Even if it is impossible to prevent the fluid leakage from between the first seal element and the second seal element with the contact pressure at the contact portion, the contact portion corresponding to the small convex portion has a sufficient pressure to seal the fluid leakage. Since the contact surface pressure remains, internal leakage is prevented.

In addition, even if the caulking or the like is insufficient, the decrease in the clamping force at the outer peripheral edge of the second seal element is compensated for by the increase in the contact surface pressure due to the small projection, and the second seal element is rotated by the rotating shaft. It can be prevented from rotating around with.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments.

FIG. 1 shows a rotary shaft seal according to the present invention,
The rotating shaft seal is fitted between the hole 2 of the housing 1 such as a compressor case and the rotating shaft 3 and slidably contacts with the outer peripheral surface 4 of the rotating rotating shaft 3 so as to form a fluid storage chamber. The fluid M in R is sealed.

In the illustrated example, a retaining ring 5 fixed to the inner peripheral surface 2a of the hole 2 of the housing 1 prevents the rotary shaft seal from coming off.

Thus, the rotary shaft seal comprises an annular first holding member 6 having an inner flange 10 at one end edge (on the side of the fluid storage chamber R), and a first seal held by the first holding member 6. An element 7, an inverted second L-shaped annular holding metal fitting 8 fitted inside the first holding metal fitting 6, and a caulking T at the other end edge (on the low pressure side A) of the first holding metal fitting 6. A second sealing element 9 made of a synthetic resin (such as a fluororesin (PTFE) such as an ethylene tetrafluoride resin) sandwiched between the holding metal member 8 and the first sealing element 7.

The first sealing element 7 made of a rubber elastic material is coated on the outer peripheral surface 14 of the first holding metal fitting 6 and the (outer and inner) surfaces of the inner flange portion 10. Is done.

FIG. 2 shows a free state of the first seal element 7. As shown in FIGS. 2 and 1, the annular first seal element 7 has a seal lip which comes into contact with the outer peripheral surface 4 of the rotating shaft 3. Part 11 and an outer peripheral contact piece 12 abutting on the inner peripheral surface 2 a of the hole 2 and covering the outer peripheral surface 14 of the first holding member 6.
And a connecting piece 13 having a U-shaped cross section for connecting the outer peripheral contact piece 12 and the seal lip 11 and covering the surface of the inner flange 10.
And consisting of

The seal lip 11 has a substantially U-shaped cross section, and its tip end is inclined at a predetermined angle in the direction of the inner diameter and in the direction of the fluid storage chamber R. At the tip of the seal lip 11,
A sharp inner peripheral ridge portion 11a is formed to project in the inner diameter direction and to contact (slidably contact) the outer peripheral surface 4 of the rotating shaft 3 in a substantially line contact manner, and when the rotating shaft 3 is stationary, the inner peripheral protrusion 11a is formed. The ridge 11a elastically contacts and seals the fluid M. The seal lip
11 is finished as it is molded.

A plurality of outer peripheral ridges 15 are formed on the outer peripheral surface of the outer peripheral contact piece 12. The outer peripheral ridges 15 are brought into close contact with the inner peripheral surface 2 a of the hole 2, and The leakage of the fluid M from the fluid storage chamber R to the low-pressure side A on the surface 2a side is prevented.

As shown in FIG. 2 and FIG.
13 has an annular flat plate portion 16 coated on the inner end surface 10a of the inner flange portion 10 of the first holding fitting 6, and the first end surface 16a of the flat plate portion 16 that comes into contact with the second seal element 9 has a first flat surface. Holding bracket 6
An annular small convex portion 17 centered on the axis of is formed.

Further, an inner small concave portion 18 is formed along a ridge portion on the inner diameter side of the small convex portion 17, and an outer small concave portion 19 is formed along a ridge portion on the outer diameter side of the small convex portion 17. . In the illustrated example, the small convex portion 17 and the inner and outer small concave portions 18 and 19 are each formed in an arc-shaped cross section.

Next, although not shown, the second seal element 9 is in the shape of an annular flat plate in a state (free state) before the rotary shaft 3 is inserted, and its inner peripheral edge is free. The edge is on a plane orthogonal to the axis.

When inserted into the rotary shaft 3, the inner peripheral edge of the second seal element 9 is bent toward the fluid storage chamber R side (high pressure side), and is fixed to the outer peripheral surface 4 of the rotary shaft 3. The seal lip portions 22 are formed by making contact with each other at a width as shown in FIG.

On the rotating shaft contact surface 23 of the seal lip portion 22,
A plurality of concentric inclined grooves H... Centered on the axis of the annular flat second seal element 9 in the free state are formed by cutting in a lathe.

Although the groove H is closed in the free state, the inner peripheral edge of the second seal element 9 is bent as shown in FIG.
To the contact surface pressure sufficient to seal the leakage of the fluid M from the fluid storage chamber R to the low-pressure side A in a region between the grooves defined by the open grooves H. , Can be enhanced.

By the way, when the rotating shaft 3 is rotating, the seal lip 11 of the first seal element 7 is finished as it is by molding, so that the seal lip 11
Fluid M slightly leaks from between 11 and the outer peripheral surface 4 of the rotating shaft 3 to the second seal element 9 side.
It has a lubricating action for preventing wear and heat generation of the seal lip portions 11 and 22.

The groove H may be a spiral groove centered on the axis of the annular flat second seal element 9 in a free state.
The spiral groove is formed so that the fluid M is returned to the fluid storage chamber R by the action of the screw pump (pumping effect).

The one end face 20a of the (non-curved) annular flat outer peripheral portion 20 of the second seal element 9 is brought into contact with the end face 16a of the flat plate portion 16 of the first seal element 7, and the outer peripheral edge portion is formed. The inner flange portion 21 of the second holding member 8 is brought into contact with the other end surface 20b of the second member 20, and the second holding member 8 is pressed in the direction of the flat plate portion 16 by the caulking T of the first holding member 6 (see FIG. 1). Then, the outer peripheral edge 20 of the second seal element 9 is clamped.

As a result, one end face 20a of the outer peripheral edge 20 of the second seal element 9 and the end face 16a of the flat plate portion 16 of the first seal element 7 come into close contact with a predetermined contact surface pressure. The so-called internal leak, in which the fluid M leaked from the seal lip portion 11 to the second seal element 9 side leaks to the low pressure side A through the space between the first seal element 7 and the second seal element 9 as shown by the arrow F. , Can be prevented.

As shown in FIG. 3, the end face 16a of the flat plate portion 16 of the first seal element 7 and the one end face 20a of the outer peripheral edge 20 of the second seal element 9 are formed in an annular contact portion. The internal pressure can be sufficiently prevented by the surface pressure of the contact portion between the flat surfaces (indicated by reference character C). In addition, the small convex portion of the flat plate portion 16 is formed at one end surface 20a of the outer peripheral edge 20.
17 is compressed, the contact surface pressure distribution between the end face 16a and the one end face 20a sharply increases in a range corresponding to the small convex part 17, and the contact part between the small convex part 17 and the one end face 20a is sealed. Thus, the internal leakage can be reliably prevented.

At this time, the caulking T (see FIG. 1) is insufficient, and the one end face 20a of the outer peripheral edge 20 of the second seal element 9 is formed.
And the contact surface pressure of the end face 16a of the flat plate portion 16 of the first seal element 7 as a whole decreases, the surface pressure of the contact portion between the flat surfaces becomes insufficient, and the fluid M Even if it penetrates between the element 7 and the second sealing element 9,
Since a contact surface pressure sufficient to seal the leakage of the fluid M is maintained at the contact portion between the small convex portion 17 and the one end surface 20a, an internal leak can be prevented (see FIG. 3).

Further, even if the caulking T (see FIG. 1) is insufficient, the decrease in the clamping force of the outer peripheral edge 20 of the second seal element 9 is compensated by the increase in the contact surface pressure by the small convex portion 17, and The second seal element 9 can be prevented from rotating together with the rotating shaft 3.

The total volume of the inner small concave portion 18 and the outer small concave portion 19 is set to be larger than the volume of the small convex portion 17.
It is desirable to absorb enough at 18 and 19 to escape.

In this way, the small convex portion 17 which has lost the escape location prevents the close contact, and a gap is formed between the end surface 16a of the flat plate portion 16 and the one end surface 20a of the outer peripheral edge portion 20, so that the contact surface The pressure does not significantly decrease locally and does not impair the sealing performance.

It should be noted that the present invention is not limited to the above-described embodiment, and the design can be freely changed without departing from the gist of the present invention. For example, the number of the small protrusions 17, the inner small recesses 18, and the outer small recesses 19 may be plural and concentrically arranged, and the position and shape of each may be freely changed.

[0037]

Since the present invention is configured as described above, the following effects can be obtained.

In the rotary shaft seal according to the present invention, the small convex portion 17 of the flat plate portion 16 of the first seal element 7 is compressed at one end surface 20a of the outer peripheral edge portion 20 of the second seal element 9 so that the small convex portion is formed. Since the contact surface pressure shows a peak at the portion corresponding to 17, the leakage of the fluid M from the space between the first seal element 7 and the second seal element 9 to the low pressure side A can be reliably sealed, and the internal leak is prevented. it can.

The caulking T or the like of the first holding bracket 6 is insufficient.
Even if the contact surface pressure between the one end surface 20a of the outer peripheral edge 20 of the second seal element 9 and the end surface 16a of the flat plate portion 16 of the first seal element 7 is entirely reduced, the contact between the small convex portion 17 and the one end surface 20a is maintained. Since the fluid M can be prevented from leaking at the portion, the sealing performance against the internal leak is stabilized, and the co-rotation of the second seal element 9 with the rotating shaft 3 can be prevented.

The mold for molding the first seal element 7 need only be processed with molding surfaces corresponding to the small projections 17, the inner small recesses 18 and the outer small recesses 19, so that the present invention can be easily applied. Cost increase can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part showing a free state of a first seal element.

FIG. 3 is an enlarged sectional view of a main part.

FIG. 4 is a sectional view showing a conventional example.

[Explanation of symbols]

 6 First holding metal fitting 7 First sealing element 8 Second holding metal fitting 9 Second sealing element 10 Inner flange 10a Inner end surface 14 Outer peripheral surface 16 Flat plate portion 16a End surface 17 Small convex portion 18 Small internal concave portion 19 Small external concave portion 20 External peripheral edge Part 20a One end face 20b The other end face

Claims (1)

(57) [Claims] An outer peripheral surface of an annular first holding member having an inner flange portion at one end edge and a surface of the inner flange portion are covered with a first sealing element made of a rubber elastic body. The one end surface of the annular flat plate-shaped outer peripheral edge of the synthetic resin second seal element is brought into contact with the end surface of the annular flat plate portion of the first seal element coated on the inner end surface of the portion, and The other end surface of the outer peripheral edge portion of the two seal elements is pressed by a second holding metal in the direction of the flat plate portion of the first seal element, and is a rotary shaft seal holding the second seal element. In a state before assembly by attachment, the flat surface of the first seal element protrudes outward from the end surface of the flat portion.
A small convex portion is formed so as to protrude, and is recessed inward from the end surface of the flat plate portion along the skirt portion on the inner diameter side of the small convex portion.
To form a small recess within it, and along the foot of the mountain portion of the outer diameter side of the small convex portion, the rotation shaft seal, characterized in that the formation of the outer small recesses recessed inward from the end face of the flat plate portion .