JP4595793B2 - Shaft seal structure - Google Patents

Description

  The present invention relates to a shaft seal structure, and more particularly to a shaft seal structure having an oil seal for a rotating shaft and a presser plate for preventing the oil seal from coming off.

As a conventional shaft seal structure, for example, a shaft seal structure 50 using an oil seal 55 shown in FIG. 3 is known.
In this type of shaft seal structure 50, a shaft case 51 corresponding to a stationary member and a rotation shaft 53 as a shaft member that rotates with respect to the shaft case 51 are disposed, and the shaft case 51 and the rotation shaft 53 are disposed between each other. An annular gap is formed on the surface.
The oil seal 55 disposed in the annular gap is held by the shaft case 51, and the inner diameter portion of the oil seal 55 includes an annular lip portion that is in sliding contact with the outer peripheral surface 54 of the rotating shaft 53.

In FIG. 3, the right (inner) lip portion is the main lip portion 57, which prevents lubricating oil leakage from the inside of the shaft case 51.
Further, the left (outside) lip portion in FIG. 3 is a dust lip portion 58, which prevents intrusion of foreign matters such as dust and moisture from the outside of the shaft case 51.
The outer diameter portion of the oil seal 55 includes a holding portion 56 that is held by the shaft case 51.
Incidentally, this type of oil seal 55 is a general oil seal as the oil seal 55 for the rotating shaft 53, and is an oil seal 55 mounted from the outside of the shaft case 51.
Further, in the shaft seal structure 50, an annular presser plate 60 that is in contact with the outer end surface 59 of the oil seal 55 is held.
A C-ring 61 is mounted in the mounting groove 52 of the shaft case 51, and the presser plate 60 is prevented from coming off by the C-ring 61 disposed outside the presser plate 60.

  In this shaft seal structure 50, when the pressure of the lubricating oil or the mechanical force acts as an internal pressure on the oil seal 55, the oil seal 55 moves outward. At this time, the presser plate 60 moves the oil seal 55. To prevent.

On the other hand, there is an oil seal having a side lip as a related prior art.
In this type of oil seal, a main lip, a dust lip, and a side lip each correspond to a lip portion, and each lip is integrally formed.
The oil seal is prevented from coming off from the case corresponding to the stationary member by a retaining ring corresponding to the presser plate.
The side lip is slidably contacted with a flange-shaped rotating end face that is stretched in the radial direction of the shaft member (see, for example, Patent Document 1).

Furthermore, as another related art, there is a packing used for an operation valve for operating a hydraulic machine.
In this packing, a flange portion provided on a metal reinforcing ring and a dust seal provided with a dust strip are overlapped and interposed between a valve stem and a valve body by a packing presser.
That is, the dust seal having the dust lip is separated from the flange portion having the seal lip (see, for example, Patent Document 2).

As another related prior art, there is a sealing device for a reciprocating shaft.
The oil seal in this reciprocating shaft sealing device is composed of a main lip that is in close contact with the outer peripheral surface of the piston rod facing the inner side in the axial direction with a metal mounting ring, and an outer peripheral lip that seals between the outer cylinder and the rod guide. The dust seal is integrally molded with a duster rubber-like elastic material that is in close contact with the outer peripheral surface of the piston rod while facing the outside in the axial direction on a metal mounting ring. (For example, see Patent Document 3).
JP-A-8-14399 Japanese Utility Model Publication No. 56-47411 JP 2005-90569 A

In the conventional shaft seal structure shown in FIG. 3, when the internal pressure acting on the inner end surface of the oil seal is large, the radial dimension of the press plate is increased so that the press plate widely contacts the outer end surface of the oil seal. Must be set.
When the radial dimension of the presser plate is set to be large, the exposed area on the outer end face of the oil seal is relatively reduced, and for example, it is difficult to provide the side lip shown in Patent Document 1 on the oil seal.
In addition, it is conceivable to use an oil seal with a high pressure resistance even when the internal pressure is large. However, due to structural differences in the oil seal, the oil seal is installed from the inside of the shaft member. May be subject to restrictions.

  On the other hand, even when the dust seal having the dust lip shown in Patent Document 2 is separate from the flange portion having the seal lip, it is difficult to provide the side lip if the radial dimension of the packing presser is set large. It remains the same.

On the other hand, in the technique shown in Patent Document 3, a dust lip is integrally formed on another metal mounting ring separately from the oil seal in which the main lip and the outer peripheral lip are integrally formed on the metal mounting ring. Although provided, the piston rod corresponding to the shaft member is not a shaft member that rotates positively.
That is, the oil seal shown in Patent Document 3 is not an oil seal configured on the assumption that the shaft member is positively rotated, and is not an oil seal suitable for the rotation of the shaft member.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a new lip body such as a side lip when the oil seal is an oil seal applied to a rotating shaft member such as a rotating shaft. The object is to provide a shaft seal structure that can be provided independently of the oil seal.

In order to achieve the above object, according to the present invention, a stationary member and a shaft member that rotates with respect to the stationary member are arranged, and the shaft member has a flange-like shape that faces the rotating shaft and an outer end surface of the stationary member. An annular member, the annular member is bent at a plurality of locations in the outer diameter direction , an annular gap is formed between the stationary member and the shaft member, and an oil seal disposed in the gap is Held by a stationary member, an inner diameter portion of the oil seal includes an annular lip portion slidably contacting an outer peripheral surface of the shaft member, and an outer diameter portion of the oil seal includes a holding portion held by the stationary member; The oil seal is held by the holding portion by being inserted from the outside of the stationary member, and the stationary member has a shaft seal structure that holds an annular presser plate that comes into contact with the outer end surface of the oil seal. Board , Characterized in that independently of the said oil seal having an inner surface in sliding contact annular lip of said annular member.

  In the present invention, since the annular retainer plate has an annular lip body that is in sliding contact with the outer peripheral surface of the shaft member independently of the oil seal, the dimension in the radial direction of the retainer plate is set large, and the outer end surface of the oil seal Even if the exposed area in the case is relatively small, a lip body such as a side lip can be provided other than the oil seal without difficulty.

  In the present invention, in the above shaft seal structure, the lip body may be formed of a material different from the lip portion of the oil seal.

  In this case, the material of the lip body in the holding plate located outside the oil seal and the material of the lip part in the oil seal are different, so that the material can be selected in accordance with the functions required for the lip body and the lip part. it can.

  According to the present invention, when the oil seal is an oil seal applied to a rotating shaft member such as a rotating shaft, a new lip body such as a side lip can be provided independently of the oil seal.

(First embodiment)
The shaft seal structure according to the first embodiment will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing the shaft seal structure according to the first embodiment by cutting along the axial direction of the shaft member.
As shown in FIG. 1, the shaft seal structure 10 according to this embodiment includes an oil seal 22 mounted on a shaft case 11 that is a stationary member, a presser plate disposed outside the oil seal 22, and a shaft member. The rotary shaft 18 mainly includes a lip body 33 that is slidably contacted with the annular member 19 and a C ring 34 that prevents the retainer plate 32 from coming off.

[About shaft case and rotating shaft]
First, the shaft case 11 and the rotating shaft 18 will be described.
The shaft case 11 has an insertion hole 16 through which a rotating shaft 18 that rotates with respect to the shaft case 11 is inserted.
The rotating shaft 18 inserted through the insertion hole 16 is supported by a bearing (not shown) on the inner side (right side in FIG. 1) of the shaft case 11.
A flange-shaped annular member 19 facing the outer end surface 12 of the shaft case 11 is attached to the rotating shaft 18, and the annular member 19 constitutes a shaft member together with the rotating shaft 18.
The annular member 19 is a member for making it difficult for foreign matter (for example, dust and moisture) to enter from the outside of the shaft case 11, and is bent at a plurality of locations in the outer diameter direction as shown in FIG.

An annular gap is formed between the shaft case 11 and the rotating shaft 18 in the vicinity of the outside of the shaft case 11 in the insertion hole 16.
In the gap, a space portion 17 is formed that is relatively wide from the outer end surface 12 of the shaft case 11 toward the inside.
The space portion 17 is a space portion in which the oil seal 22 is accommodated, and a part of the inner peripheral surface 13 of the shaft case 11 facing the space portion 17 functions as a holding surface that holds the oil seal 22.
A part of the inner peripheral surface 13 that functions as a holding surface is a surface parallel to the axial direction of the rotating shaft 18.
A mounting groove 14 for mounting the C ring 34 is formed near the outside of the inner peripheral surface 13 of the shaft case 11 facing the space portion 17.

On the inner side in the axial direction of the space portion 17, an extending portion 15 of the shaft case 11 is formed that extends toward the rotating shaft 18 so as to reduce the diameter of the insertion hole 16.
The inner peripheral surface of the extending portion 15 is in a state of being close to and facing the outer peripheral surface 20 of the rotating shaft 18.
The inner end face 30 of the attached oil seal 22 is in contact with the outer surface of the extending portion 15, and the movement of the oil seal 22 to the inside is restricted.

[About oil seal]
Next, the oil seal 22 will be described.
The oil seal 22 is held by the shaft case 11 and is in sliding contact with the rotating rotating shaft 18.
The oil seal 22 of this embodiment includes a metal-made reinforcing ring 23 having a substantially L-shaped cross section, an elastic body 24 made of fluoro rubber surrounding the reinforcing ring 23, and a garter spring 31 that applies a tightening force to the rotating shaft 18. It consists of and.
The reinforcing ring 23 has a function of maintaining the strength of the oil seal 22 as a core material of the oil seal 22.

Since the elastic body 24 is made of fluororubber, it has excellent heat resistance. The rotating shaft 18 rotates at a high speed, and the elastic body 24 is hardly changed even if it receives heat from sliding contact with the rotating shaft 18. Absent.
The cross-sectional form of the elastic body 24 is substantially U-shaped, and the elastic body 24 has a holding portion 25 corresponding to a holding surface located on the outer periphery of the reinforcing ring 23 and a cross-sectional mountain shape set near the extending portion 15. A main lip portion 26 as a lip portion and a dust lip portion 27 as another lip portion located outside the main lip portion 26 are formed.
The holding portion 25 forms an outer peripheral surface that is held by a part (holding surface) of the inner peripheral surface 13 of the shaft case 11.
That is, the outer diameter portion of the oil seal 22 includes a holding portion 25 that is held by the shaft case 11.

The main lip portion 26 is in contact with the outer peripheral surface 21 of the rotating shaft 18 in the circumferential direction, and prevents lubricating oil leakage from the inside to the outside of the oil seal 22.
Therefore, when the rotating shaft 18 rotates, the main lip 26 comes into sliding contact with the outer peripheral surface 21 of the rotating shaft 18.
An annular groove 28 is formed on the outer peripheral side of the main lip portion 26, and a garter spring 31 is attached to the annular groove 28.
The tightening force of the garter spring 31 mounted in the mounting groove 28 is a biasing force that presses the main lip portion 26 against the outer peripheral surface 21 of the rotating shaft 18.
The dust lip part 27 is located outside the main lip part 26 and is stretched slightly outward.
The tip of the dust lip 27 abuts the outer peripheral surface 21 of the rotating shaft 18 in the circumferential direction, and prevents foreign matter (dust, moisture, etc.) from entering from the outside of the oil seal 22.
That is, the inner diameter portion of the oil seal 22 includes an annular main lip portion 26 and a dust lip portion 27 that are in sliding contact with the outer peripheral surface 21 of the rotating shaft 18.

Further, the outer end surface 29 of the elastic body 24 forms an annular flat surface perpendicular to the axial direction of the rotating shaft 18, constitutes the outer end surface of the oil seal 22, and is further elastic that is positioned inside the reinforcing ring 23. The inner end face 30 of the body 24 constitutes the inner end face of the oil seal 22.
In this embodiment, the shaft case 11 which is the inside of the oil seal 22 is filled with lubricating oil.

[About the presser plate]
Next, the presser plate 32 will be described.
In a state where the oil seal 22 is attached to the shaft case 11, the annular pressing plate 32 is disposed outside the oil seal 22.
In this embodiment, the presser plate 32 is in contact with most of the outer end surface 29 of the oil seal 22.
The holding plate 32 has an annular lip body 33 that is in sliding contact with the rotary shaft 18 independently of the oil seal 22.
As shown in FIG. 1, the presser plate 32 includes a lip body 33 formed of an elastic material.
The base portion of the lip body 33 is welded over a part of the holding plate 32 near the outer peripheral surface and a part of the outer surface near the inner peripheral surface.
The lip body 33 has a base portion to a distal end portion that is extended outward so as to be slightly away from the outer peripheral surface 21 of the rotating shaft 18, and the outer end of the lip body 33 is in contact with the inner surface of the annular member 19.
The lip body 33 prevents foreign matter entering between the annular member 19 and the shaft case 11 from entering the oil seal 22.
That is, the lip body 33 substantially functions as a side lip.
In this embodiment, the lip body 33 is made of nitrile rubber (NBR), which is inferior in heat resistance to the fluororubber used in the oil seal 22 but has excellent water resistance.

[About C-ring]
The C-ring 34 is a member for preventing the presser plate 32 from coming off and is a known member, and the C-ring 34 is mounted in the mounting groove 14 of the shaft case 11.
In this embodiment, the C-ring 34 can contact over the vicinity of the outer periphery of the outer surface of the presser plate 32.
When the oil seal 22 attempts to move inward due to internal pressure, the oil seal 22 and the presser plate 32 are restricted from moving by contacting the outer surface of the presser plate 32.

Next, a procedure for assembling each element constituting the shaft seal structure 10 according to this embodiment will be described.
First, the oil seal 22 is attached to the shaft case 11 from the outside of the shaft case 11.
Next, the pressing plate 32 faces the outside of the oil seal 22, and the C ring 34 is mounted in the mounting groove 14.
When the rotary shaft 18 is finally inserted into the insertion hole 16, the assembly of the elements constituting the shaft seal structure 10 is completed.

Next, the operation of the shaft seal structure 10 according to this embodiment will be described.
When the rotating shaft 18 rotates, the main lip portion 26 and the dust lip portion 27 in the oil seal 22 are in sliding contact with the outer peripheral surface 21 of the rotating shaft 18.
At this time, the lip body 33 in the pressing plate 32 is in sliding contact with the inner surface of the annular member 19.
Lubricating oil filled in the shaft case 11 inside the oil seal 22 is less likely to be blocked by the main lip portion 26 and leak to the outside of the oil seal 22.

On the other hand, foreign matter entering from between the annular member 19 and the shaft case 11 is first blocked by the lip body 33.
Since the lip body 33 uses a nitrile rubber excellent in water resistance, there is almost no possibility that the lip body 33 will be altered even when repeatedly exposed to moisture.
When there is foreign matter that enters the shaft case 11 beyond the lip body 33, the foreign material is blocked by the dust strip portion 27.

Incidentally, there are cases where the internal pressure acts on the oil seal 22 when the pressure of the lubricating oil is high or when a mechanical force due to a slight movement of the rotating shaft 18 in the axial direction is received.
In this case, the oil seal 22 tends to move outward with respect to the shaft case 11.
At this time, even if the oil seal 22 is about to move relative to the shaft case 11, the presser plate 32 that is prevented from coming off by the C ring 34 restricts the movement of the oil seal 22 to the outside.

According to this embodiment, the following effects can be obtained.
(1) The annular retainer plate 32 has an annular lip body 33 that is slidably in contact with the inner surface of the annular member 19 independently of the oil seal 22, but the radial dimension of the retainer plate 32 is set large. Even if the exposed area of the outer end face 29 of the oil seal 22 is relatively reduced, the lip body 33 that functions as a side lip can be provided without the oil seal 22 without difficulty.
(2) Since the material of the lip body 33 located outside the oil seal 22 is different from the material of the main lip portion 26 and the dust lip portion 27 in the oil seal 33, the lip body 33 and the main lip portion 26 A material can be selected in accordance with a function required for the strip portion 27.

( Reference example )
Next, the shaft seal structure according to the reference example will be described.
As shown in FIG. 2, each element of the shaft seal structure 40 according to the reference example has basically the same configuration as each element of the shaft seal structure 10 of the first embodiment except for the lip body.
Therefore, in the shaft seal structure 40 of the reference example , the same reference numerals used in the first embodiment are used in common for the elements common to the first embodiment, and the description of the first embodiment is used.

In this reference example , the lip body 41 provided on the presser plate 32 is provided so as to contact the outer peripheral surface 21 of the rotating shaft 18, not the annular member 19 on the rotating shaft 18.
Therefore, the lip body 41, the dust seal portion 27, and the main lip portion 26 are sequentially positioned from the outside to the inside.
The reason why the lip body 41 is brought into contact with the outer peripheral surface of the rotary shaft 18 is that the lip body 41 and the rotary shaft 18 are in sliding contact even if the rotary shaft 18 moves in the axial direction with respect to the shaft case 11. Does not change, and the lip body 41 does not leave the rotating shaft 18.
Incidentally, when the lip body 33 abuts on the inner surface of the annular member 19 as in the lip body 33 in the first embodiment, when the rotary shaft 18 moves greatly in the axial direction with respect to the shaft case 11, the lip body There is a possibility that 33 is separated from the rotary shaft 18 or the lip body 33 is excessively deformed.
In the shaft seal structure 40 according to the reference example , since the lip body 41 is in sliding contact with the outer peripheral surface 21 of the rotating shaft 18, the above problem does not occur.

The present invention is not limited to the above-described first embodiment and reference example , and various modifications are possible within the scope of the gist of the invention. For example, the following modifications may be made.
In the first embodiment and the reference example , the material of the lip body in the holding plate and the material of the lip portion in the oil seal are different from each other. However, this does not prevent the two materials from matching. In addition, the material of the elastic body of the oil seal is not limited to fluororubber, and an appropriate elastic material can be selected, and other elastic materials such as acrylic rubber may be employed for the lip body.
In the first embodiment and the reference example , the retaining plate is prevented from coming off by the C-ring attached to the shaft case. However, for example, the retaining plate may be directly attached to the shaft case and fixed. Further, the lip body is not only welded to the presser plate, but, for example, a lip body may be disposed between two presser plates and the lip body may be sandwiched between the presser plates. Any means can be used as long as it can be attached to the plate.
In the first embodiment and the reference example , application of the shaft seal structure was not specifically shown, but it can be applied to, for example, an axle near a brake in a vehicle and a rotating shaft of a drive shaft. In addition to automobiles, the present invention can be applied to industrial vehicles including cargo handling vehicles and construction vehicles.

It is sectional drawing which fractures | ruptures and shows the shaft seal structure which concerns on 1st Embodiment along the axial direction of a shaft member. It is sectional drawing which fractures | ruptures and shows the principal part of the shaft seal structure which concerns on a reference example along the axial direction of a shaft member. It is sectional drawing which fractures | ruptures and shows the principal part of the shaft seal structure which concerns on a prior art along the axial direction of a shaft member.

Explanation of symbols

10, 40, 50 Shaft seal structure 11, 51 Shaft case 12 Outer end face 13 Inner peripheral face 14, 52 Mounting groove 15 Extension part 16 Insertion hole 17 Space part 18, 53 Rotating shaft 19 Annular member 20, 21, 54 Outer peripheral face 22, 55 Oil seal 24 Elastic body 26, 57 Main lip part 27, 58 Dustrip part 32, 60 Holding plate 33, 41 Lip body 34, 61 C ring

Claims (2)

A stationary member and a shaft member that rotates with respect to the stationary member are disposed, and the shaft member includes a rotation shaft and a flange-shaped annular member that faces an outer end surface of the stationary member, and the annular member is It is bent at a plurality of locations in the outer diameter direction , an annular gap is formed between the stationary member and the shaft member, and an oil seal disposed in the gap is held by the stationary member, and the inner diameter of the oil seal The portion includes an annular lip portion that is in sliding contact with the outer peripheral surface of the shaft member, the outer diameter portion of the oil seal includes a holding portion that is held by the stationary member, and the oil seal extends from the outside of the stationary member. held by the holding portion by the insertion, the stationary member is a shaft seal structure for holding an outer edge abutting the annular holding plate of the oil seal, the pressing plate, the independently with said oil seal Shaft seal structure characterized by having an inner surface in sliding contact annular lip of Jo member.   The shaft seal structure according to claim 1, wherein the lip body is formed of a material different from that of the lip portion of the oil seal.

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