JP2000320687A - Dust seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain high sealing ability. SOLUTION: A dust seal 2 comprises a reinforcing ring 4; a sealing member 6 mounted on the reinforcing ring 4; and a lip part 66 with which the sealing member 6 is provided. An elastic ring body 7 is held in a fitted-in state on the outer peripheral surface of the sealing member 6. When the lip member 66 is fitted in the peripheral surface of a shaft 128, the lip part 66 is forced into pressure contact with the outer peripheral surface of the shaft 128 through the elastic compression force of the elastic ring body 7 in addition to its own elastic compression force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing for various machines, for example, a bearing for connecting a boom and an arm of a hydraulic shovel as a construction machine, and a bearing for connecting an arm and a bucket. The present invention relates to a dust seal applied for preventing intrusion (dust protection), waterproofing, and the like.

[0002]

2. Description of the Related Art A dust seal is used in a bearing portion of a machine, for example, a bearing portion for connecting a boom and an arm of a hydraulic shovel as a construction machine to prevent dust from entering (dustproof) or waterproof. . The bearing portion is supported by a pair of boss portions provided on the arm side and through holes having a common axis formed in each of the boss portions so as to be rotatable relative to each other via bearings. And Both ends of the shaft protrude outside each of the bosses, and the connection holes of the yoke provided on the boom side are fitted to both ends of the protruded shaft. One end of the shaft is fixed to one side of the yoke portion by fixing means. A snap ring is attached to the other end of the shaft adjacent to the other side of the yoke. The bearing is configured as described above, and the arm is supported so as to be rotatable relative to the boom.

In the above bearing, each of the bearings is constituted by a plain bearing. An annular groove extending in the circumferential direction and a plurality of grooves extending linearly in the axial direction intersecting with the annular groove are formed on the inner peripheral surface of each of the bearings,
A through hole is formed in the portion where the annular groove is formed. Each of the grooves and each of the through holes constitute a grease passage. A grease injection hole is formed in each of the bosses, and one end of each of the injection holes is open to the surface of the boss, and the other end communicates with the through hole of the corresponding bearing. Grease is injected (press-fitted) from each of the injection holes of the boss. Grease is supplied between the bearing and the shaft from each through hole of the corresponding bearing through each groove.

An annular mounting portion for dust sealing is formed at one axially outer end of each of the bosses and at one end adjacent to the axially outer one end of each bearing. A dust seal is mounted in each of the mounting sections. A typical example of the dust seal includes a reinforcing ring having an L-shaped cross section and an annular sealing member integrally attached to the reinforcing ring. The seal member includes an annular lip portion inclined and extending in a direction approaching the axial line toward a direction away from one end of the corresponding bearing in the axial direction, and an annular concave portion (recess portion) formed radially outside the lip portion. ). The sealing surface of the sealing member is defined by the inner peripheral surface of the distal end of the lip, and the inner peripheral surface of the distal end of the lip is pressed against the outer peripheral surface of the shaft by its own elastic compressive force.

[0005]

Since the sealing of the bearing portion by the above-mentioned conventional dust seal is performed only by the elastic compressive force of the lip portion of the sealing member, the binding force on the outer peripheral surface of the shaft is relatively small. Since it is small and has a large creep, the binding force changes and the initial binding force cannot be maintained, and the sealing performance is reduced. If the sealing property is reduced, the penetration of dust increases, and the durability of the bearing part is reduced. Furthermore, especially when a bearing for a long-time greasing interval is mounted as a bearing, there is a tendency that the lubricant on the sealing surface at the lip portion is gradually lost, and as a result, the friction coefficient increases. Wear is promoted. In the above-mentioned conventional dust seal, since the seal member has an annular concave portion (recess portion) on the outer side in the radial direction of the lip portion, earth and sand are easily deposited in the concave portion. When earth and sand accumulate in the recess, the possibility of intrusion from the sealing surface of the lip increases. Furthermore, when the shaft (pin) is inserted into the bearing through the lip portion of the seal member (at the time of assembling), if the tip of the shaft eccentrically contacts the concave portion of the lip portion of the seal member, the lip portion is moved. There is a possibility that it is easily inverted and damaged.

The present invention has been made based on the above-mentioned facts, and has as its object the purpose of maintaining a relatively large tightening force on the outer peripheral surface of the shaft and maintaining the initial tightening force even when creep and wear occur on the lip portion. It is an object of the present invention to provide a novel dust seal that can maintain high sealing performance.

Another object of the present invention is to provide a novel dust seal capable of reducing the coefficient of friction of the sealing surface at the lip, and thus reducing the wear of the sealing surface.

[0008] Other objects and features of the present invention are directed to embodiments of a dust seal constructed in accordance with the present invention.
It will become apparent from the following description, which is described in detail with reference to the accompanying drawings.

[0009]

According to one aspect of the present invention, a dust seal includes a reinforcing ring and an annular sealing member mounted on the reinforcing ring, the sealing member having an annular lip. In the above, an elastic ring body is fitted and held on the outer peripheral surface of the lip portion, and when the lip portion is fitted on the outer peripheral surface of the shaft to be sealed, the elastic ring body is applied in addition to its own elastic compressive force. A dust seal is provided which is brought into pressure contact with the outer peripheral surface of the shaft by elastic compression force of a body.

According to another aspect of the present invention, a dust seal including a reinforcing ring and an annular sealing member mounted on the reinforcing ring, wherein the sealing member has an annular lip portion, An elastic ring body fitted and held on the outer peripheral surface of the shaft, and an annular auxiliary seal member mounted on the reinforcing ring. The seal member and the auxiliary seal member are fitted on the outer peripheral surface of a shaft to be sealed. Then, the lip portion of the seal member is pressed against the outer peripheral surface of the shaft by the elastic compressive force of the elastic ring body in addition to the elastic compressive force of itself, and the inner peripheral surface of the auxiliary seal member is An annular gap is formed between the inner peripheral surface of the lip and the outer peripheral surface of the shaft and the inner peripheral edge of the auxiliary seal member on the side of the lip that is pressed against the outer peripheral surface of the shaft. , A dust seal characterized in that:

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. 1 to 5
, Substantially the same parts are denoted by the same reference numerals. Referring to FIG. 1, a hydraulic excavator generally designated by reference numeral 100 includes a lower traveling body 102 and a lower traveling body 102.
And an upper revolving body 104 mounted on the upper part so as to be freely rotatable. The cab 106 and the engine 1
08, a working machine 110, and the like. Work machine 110
A boom 112 whose one end is rotatably supported by the upper swing body 104; an arm 114 whose one end is rotatably supported at the other end of the boom 112; and the other end of the arm 114 Bucket 11 rotatably supported on
6 is provided. The boom 112 includes a boom cylinder 11 provided between the boom 112 and the upper swing body 104.
8, arm 114 is connected to arm 11
Arm cylinder 1 provided between arm 4 and boom 112
20, and the bucket 116 is configured to be operated by a bucket cylinder 122 provided between the bucket 116 and the arm 114.

Referring to FIGS. 1 and 2, the bearing provided between boom 112 and arm 114
And a pair of bosses 124 provided on the fourth side.
Through hole 125 having a common axis L formed in each of
And a shaft (pin) 128 which is supported via a bearing 126 so as to be relatively rotatable. Both ends of the shaft 128 are positioned to protrude outside each of the bosses 124. Yoke portions 130 provided on the boom 112 side are fitted to both end portions of the shaft 128 protruding outward from each of the boss portions 124 via connection holes 132 formed in the boom 112 side. At one end of the shaft 128, a plate member 134 constituting a part of the fixing means is integrally fixed, and the plate member 134 is also fixed to one side of the yoke part 130 by a bolt 136 constituting another part of the fixing means. Have been. A snap ring 138 is attached to an annular groove (not shown) formed in the outer peripheral portion of the other end of the shaft 128 adjacent to the other side of the yoke portion 130. Shaft 128 is boom 1
It is integrally fixed to the twelve yoke portions 130 so as not to rotate relative to each other. The bearing is configured as described above, and the arm 114 is rotatably supported with respect to the boom 112.

In the above bearing portion, each of the bearings 126 is constituted by a plain bearing known per se. Although not shown, the inner peripheral surface of each of the bearings 126 includes an annular groove extending in the circumferential direction, and a plurality of grooves intersecting the annular groove and extending linearly in the direction of the axis L. Is formed, and a through hole is formed in a portion where the annular groove is formed. Each of the above-mentioned grooves and each of the through holes constitute a passage for grease which is a lubricant. A grease injection hole (not shown) is formed in each of the bosses 124, and one end of each of the injection holes is opened on the surface of the corresponding boss 124, and the other end is formed in the through hole of the corresponding bearing 126. Communicating. Grease is injected from each of the injection holes of the boss 124. Grease is supplied between the bearing 126 and the shaft 128 through each groove from a through hole of the corresponding bearing 126.

Referring to FIG. 3 together with FIG.
An annular mounting portion 140 for the dust seal 2, which will be described later, is formed at one end of each of the outside holes 24 in the direction of the axis L and adjacent to one of the outside ends of each of the through holes 125 in the direction of the axis L. Have been. Each of the mounting portions 140 has an inner peripheral surface 142 having a larger diameter than the corresponding through hole 125.
And an annular step 14 formed between an inner end of the inner peripheral surface 142 and an outer end of the corresponding through hole 125 in the direction of the axis L.
And 4. The step portion 144 has an inner peripheral surface 142.
Is formed by an annular end face extending perpendicularly to the axis L from the inner end to the inner side in the radial direction. Mounting part 14
One end surface (outer surface) of the corresponding bearing 126 in the direction of the axis L is positioned on the radially inward extension of the step 144 at each of the zeros. Mounting part 14 as described above
0, the dust seal 2 of the present invention is mounted. The configuration of the bearing portion and the configuration of the dust seal 2 used for each of the boss portions 124 are substantially the same.

Referring to FIG. 7, the dust seal 2 of the present invention includes a metal reinforcing ring 4 and an annular seal member 6 integrally mounted on the reinforcing ring 4. In the following description, one side in the direction of the axis L means the right side in FIGS. 3, 4, 7, 8, and 11, and
The other direction means the left side in each of the drawings. Furthermore, the axis L is common to the axis of the dust seal 2, and therefore, all the annular members constituting the dust seal 2 (the reinforcing ring 4, the sealing member 6, the elastic ring body 7, the holding ring 8 described below). And the auxiliary seal member 9). The reinforcing ring 4 includes a cylindrical portion 4
2 and an annular flange portion 44 extending perpendicularly inward in the radial direction from one end of the other side of the cylindrical portion 42 in the direction of the axis L, and has an L-shaped cross section. The seal member 6 formed of a material having elasticity and wear resistance, for example, a synthetic rubber such as nitrile rubber (NBR) or polyurethane, or another synthetic resin having elasticity is parallel to the axis L of the seal member 6. A cylindrical portion 62, an annular main body 64 extending perpendicularly inward in the radial direction from one end of the other side in the direction of the axis L of the cylindrical portion 62, It has a lip 66 defining a peripheral portion, and an annular recess 68 formed radially outside the lip 66. The lip portion 66 is formed so as to extend from the other side in the direction of the axis L of the seal member 6 toward one side and incline in a direction approaching the axis L. The lip 66
The portion that is integrally connected to the inner peripheral edge of the main body 64 defines the base of the lip 66. The recess 68 is provided with the sealing member 6.
An inner peripheral surface concentric with the outer peripheral surface of the inner peripheral surface, an end surface extending at a right angle radially inward from one end on the inner side of the inner peripheral surface, and an axial line And an inclined surface 69 that extends inclining in a direction approaching. The inclined surface 69 is also the outer peripheral surface 69 of the lip 66. An outer peripheral surface 69 of the lip portion 66 is formed so as to be inclined at an inclination angle θ1 in a direction approaching the axis L.

The sealing member 6 has an outer peripheral surface of the cylindrical portion 62 on an inner peripheral surface of the cylindrical portion 42 of the reinforcing ring 4 and a main body 6.
4 (the surface opposite to the concave portion 68 in the direction of the axis L) on the side of the cylindrical portion 42 of the flange portion 44 of the reinforcing ring 4 and the body portion 6 of the lip portion 66.
4 and the flange portion 44 of the reinforcing ring 4 on the other side in the direction of the axis L.
The outer peripheral surface of the end portion protruding by the thickness of the inner surface of the flange portion 44 is integrally fixed to the reinforcing ring 4 by being baked. The surface of the flange portion 44 of the reinforcing ring 4 and the end surface of the lip portion 66 protruding from the main body portion 64 by the thickness of the flange portion 44 of the reinforcing ring 4 are positioned on the same plane orthogonal to the axis L. As is clear from the above description, the cylindrical portion 42 of the reinforcing ring 4 covers the outer peripheral surface of the sealing member 6, and the flange portion 44 of the reinforcing ring 4 is located on the other side (the side opposite to the concave portion 68) in the direction of the axis L of the sealing member 6. 2) is fixed to the seal member 6 so as to cover at least a part thereof.

The elastic ring 7 is fitted and held in the recess 68 of the seal member 6. The elastic ring body 7 formed of a material having elasticity, for example, synthetic rubber such as nitrile rubber (NBR) or other synthetic resin having elasticity,
A substantially trapezoidal cross section, and an axis L
A chamfer is formed at a corner on the other side of the direction, and the inner peripheral surface is formed of an inclined surface 7a which is inclined toward one side in the direction of the axis L and in a direction approaching the axis L. That is, the inner peripheral surface 7a of the elastic ring body 7 has the inclination angle θ in the direction approaching the axis L.
It is formed so as to extend obliquely with 2. As is clear from FIG. 7, the inclination angle θ2 of the inclined surface 7 a of the elastic ring body 7 with respect to the axis L is the inclined surface 69 of the concave portion 68, that is, the outer peripheral surface (the inclined surface) of the lip portion 66 of the seal member 6.
69 is slightly larger than the inclination angle θ1 with respect to the axis L. Corners formed between the small diameter side inner peripheral surface (the inner peripheral surface on one side in the axis L direction) 7a of the elastic ring body 7 and the end surface in the axis L direction (one end surface in the axis L direction) include:
An annular notch 7b having a substantially L-shaped cross section is formed. The notch 7b is formed by an annular end face extending substantially perpendicularly to the axis L radially outward from the tip defining the minimum diameter of the inner peripheral surface 7a, and an annular step defining the outer diameter of the annular end face. Become. The annular step is between the annular end surface of the notch 7b and one end surface of the elastic ring body 7 in the direction of the axis L, which is radially outward from the annular end surface of the notch 7b. It is formed. In a state where the elastic ring 7 is fitted (inserted) into the recess 68 of the seal member 6, the outer peripheral surface of the elastic ring 7 contacts the inner peripheral surface which is the maximum outer diameter surface of the recess 68, and the elastic ring 7 The surface on the other side in the direction of the axis L of the elastic ring 7 abuts on the end surface of the concave portion 68 which is the deepest portion in the direction of the axis L. It is positioned so as to protrude in one of the directions of the axis L, and the inner peripheral surface 7a of the elastic ring body 7 is
The outer peripheral surface 69 of the lip 66 is fitted to the outer peripheral surface.
As described above, the relationship of θ2> θ1 is defined between the inclination angle θ2 of the inclined surface 7a of the elastic ring body 7 and the inclination angle θ1 of the outer peripheral surface 69 of the lip portion 66. Is formed between the outer peripheral surface 69 and the inclined surface 7a of the elastic ring body 7 so as to gradually increase from one side to the other side in the direction of the axis L.

A plurality of the elastic ring members 7 are provided in the circumferential direction.
In this embodiment, it is divided into twelve. Specifically, as shown in FIGS. 5 and 6,
The elastic ring members 7 are composed of elastic arc members 77 having substantially the same configuration. Elastic arc member 7
Needless to say, the material and the cross-sectional shape forming each of the elastic ring members 7 are substantially the same as those of the elastic ring member 7 described above.
Are formed so as to be positioned on a plane coinciding with two straight lines extending at an angle of 30 degrees from the axis (L) of the optical disk. Therefore, the above-described annular elastic ring body 7 can be easily formed by arranging the end faces in the circumferential direction of the elastic arc members 77 in close contact with the elastic arc members 77 adjacent to each other and arranging them in an annular (circular) shape. At the same time, it is easily inserted and mounted in the annular concave portion 68 in that state.

The dust seal 2 also has a holding ring 8 for holding the elastic ring 7. The metal holding ring 8 includes a cylindrical portion 82 and an annular holding flange portion 84 extending radially inward at a right angle from one end of the cylindrical portion 82 on one side in the axis L direction. By pressing (shrink-fitting) the inner peripheral surface of the cylindrical portion 82 of the retaining ring 8 onto the outer peripheral surface of the cylindrical portion 42 of the reinforcing ring 4, the retaining ring 8 is
And the holding flange 8 of the holding ring 8.
4 is positioned so as to press the outer surface of the elastic ring body 7 in the direction of the axis L (one surface in the direction of the axis L) (FIG. 4).
reference). As a result, the elastic ring body 7 is fitted and held in the recess 68 in a state where it is slightly compressed in the direction toward the other side of the axis L direction (the direction toward the deepest part in the axis L direction of the recess 68) ( (See FIG. 4). The elastic ring body 7 is slightly compressed in the direction toward the other side of the axis L direction by the pressing flange 84 of the pressing ring 8 as described above, so that the elastic ring body 7 slightly protrudes from the open end of the recess 68 to one side in the axis L direction. The side surface is positioned substantially flush with one side surface of the seal member 6 (see FIG. 4). The cylindrical portion 82 of the press ring 8
The range in the axis L direction in which the inner peripheral surface is pressed so as to cover the outer peripheral surface of the cylindrical portion 42 of the reinforcing ring 4 is the entire range from one end on one side in the axis L direction to the other side in the axis L direction. Instead, the outer peripheral surface of the cylindrical portion 42 of the reinforcing ring 4 is defined so as to leave a partial area on the other side in the direction of the axis L. Therefore, in a state in which the inner peripheral surface of the cylindrical portion 82 of the press ring 8 is pressed so as to cover the outer peripheral surface of the cylindrical portion 42 of the reinforcing ring 4, the outer peripheral surface of the cylindrical portion 42 of the reinforcing ring 4 in the direction of the axis L is A partial area on the other side is exposed (see FIG. 4).

The dust seal 2 further includes a lip 66
And an annular auxiliary seal member 9 attached to the reinforcing ring 4 so as to be in close contact with the end surface of the seal member 6 on the base side of the seal member 6. An elastic material such as nitrile rubber (NB
R), an auxiliary sealing member 9 made of synthetic rubber such as polyurethane, or other elastic synthetic resin.
A cylindrical body 92 and an annular main body 94 extending at right angles radially inward from one end of the other side of the cylindrical part 92 in the direction of the axis L.
And The inner peripheral edge of the main body 94 is
6 toward one side of the auxiliary seal member 9 in the direction of the axis L (the side of the cylindrical portion 92 in the direction of the axis L) and the axis L
Is formed to extend slightly inclining in a direction approaching. A plurality of through holes 96 are formed in the inner peripheral edge of the main body 94 at intervals in the circumferential direction. In place of the plurality of through holes 96, a slit (not shown) extending from the inner peripheral surface to the outside in the radial direction by a predetermined width and a predetermined length and extending from one end in the axial direction to the other end is used. In some embodiments, On the inner peripheral edge of the auxiliary seal member 9, an end surface on the lip portion 66 side is provided with a wing (projecting portion) 97 extending from the end surface in the direction of the lip portion 66.
Are formed at intervals in the circumferential direction. The wing portion 97 is formed on the inner peripheral edge of the auxiliary seal member 9 in the radial direction inside of the through hole 96, and each inner peripheral surface is in contact with the inner peripheral surface of the auxiliary seal member 9, that is, the inner peripheral surface of the main body portion 94. It is configured to match. Each circumferential end surface of each of the blade portions 97 protruding in the direction of the lip portion 66 from the inner peripheral edge of the auxiliary seal member 9 is formed so as to extend in parallel with the axis L of the auxiliary seal member 9. In some embodiments, it is configured to extend obliquely toward one of the circumferential directions with respect to L.

The inner peripheral surface of the cylindrical portion 92 of the auxiliary seal member 9 configured as described above is connected to the outer peripheral surface of the cylindrical portion 42 of the reinforcing ring 4 (as described above, the inner peripheral surface of the cylindrical portion 82 of the holding ring 8 is press-fitted). The auxiliary seal member 9 is attached to the reinforcing ring 4 and the main body 94 of the auxiliary seal member 9 is fitted to the unexposed outer peripheral surface of the exposed partial area on the other side in the direction of the axis L. At least the flange portion 4 of the reinforcing ring 4
4 is positioned close to the surface on the other side in the direction of the axis L. In the embodiment, the other end in the direction of the axis L of the lip portion 66 of the seal member 6 is present on the radially inward extension of the surface of the flange portion 44 of the reinforcing ring 4. The main body 94 is also positioned closely to the one end surface of the lip 66 (see FIG. 4). With the auxiliary seal member 9 attached to the reinforcing ring 4 as described above, the diameter of the outer peripheral surface of the cylindrical portion 92 of the auxiliary seal member 9 is slightly smaller than the diameter of the outer peripheral surface of the cylindrical portion 82 of the holding ring 8. It is defined to be smaller (see FIG. 4).

Referring to FIG. 4, in the dust seal 2 assembled as described above, the outer peripheral surface of the cylindrical portion 82 of the press ring 8 is pressed into the inner peripheral surface 142 of the mounting portion 140 of the boss portion 124. As a result, the boss portion 124 is mounted on the mounting portion 140. Cylindrical part 92 of auxiliary seal member 9
Is defined to be slightly smaller than the outer diameter of the cylindrical portion 82 of the press ring 8, so that the press-fitting is performed smoothly and reliably, and the press-fitting allows the cylindrical portion 92 of the auxiliary seal member 9 to be formed.
Is not damaged. Dust seal 2 is boss 12
4, the surface of the main body portion 94 of the auxiliary seal member 9 (the surface on the other side in the direction of the axis L) while being mounted on the mounting portion 140 of FIG.
Is positioned substantially in close contact with the surface of the step portion 144 of the mounting portion 140 and the end surface on one side in the direction of the axis L of the bearing 126 located substantially flush with the surface. The lip 6
6 is positioned so as to extend in a direction away from the end face of the bearing 126 and in a direction approaching the axis L. The inner peripheral edge of the main body 94 of the auxiliary seal member 9 is also positioned so as to extend in a direction away from the end face of the bearing 126 and in a direction approaching the axis L. When the dust seal 2 is mounted on the mounting portion 140 of the boss portion 124 and the shaft 128 is not fitted, the inclination angle θ2 of the inner peripheral surface of the elastic ring body is
And the inclination angle θ1 of the outer peripheral surface of the lip portion 66,
The relationship of θ2> θ1 is maintained.

Referring to FIG. 3, after the dust seal 2 is mounted on the mounting portion 140 of the boss portion 124, the shaft 128 is inserted into the bearing 126 and assembled. When the outer peripheral surface of the shaft 128 is fitted to the seal member 6, the lip 6
The diameter of the inclined inner peripheral surface is defined so that the outer peripheral surface of the elastic ring is elastically expanded radially outward, so that the elastic ring body 7 is also compressed in the concave portion 68 via the lip portion 66. . Thus, the inner peripheral surface of the lip portion 66 is pressed against the outer peripheral surface of the shaft 128 by the elastic compressive force of the elastic ring body 7 in addition to the elastic compressive force of itself. As a result, the binding force of the lip portion 66 to the outer peripheral surface of the shaft 128 becomes larger than the conventional elastic compression force of the lip portion 66 alone,
Moreover, even if creep and wear occur on the lip 66,
Since the initial binding force can be maintained by the elastic compression force of the elastic ring body 7, high sealing performance can be maintained. Due to the ability to maintain high sealing properties,
Dust can be effectively prevented from entering, and the durability of the bearing portion can be improved. Dust seal 2
In a state where the lip 66 is fitted on the outer peripheral surface of the shaft 128, the elastic compressive force acting on the outer peripheral surface 69 of the lip 66
8 is defined to be larger than the elastic compressive force acting on the outer peripheral surface. This can be easily achieved by forming the elastic ring body 7 from a material having an elastic force larger than the elastic force of the lip portion 66.

This operation will be described in more detail with reference to FIG. 8. When the lip portion 66 is fitted to the outer peripheral surface of the shaft 128, the inner peripheral surface of the shaft 128 is moved radially outward by the interference S. The outer peripheral surface 69 is also enlarged. For this reason, the lip portion 6
6 is fastened to the outer peripheral surface of the shaft 128 with an elastic compressive force of F1. On the other hand, the elastic ring body 7 has a lip 66
By expanding the outer peripheral surface 69 radially outward,
The inner peripheral surface 7a is F2 with respect to the outer peripheral surface 69 of the lip portion 66.
Tighten with elastic compression force. The elastic force of the elastic ring 7 is made of a material having an elastic force greater than the elastic force of the lip portion 66, so that F2 / S>
The relationship of F1 / S is established. As a result, even if creep and wear occur in the lip portion 66, the initial binding force can be maintained by the elastic compressive force of the elastic ring body 7, and high sealing performance can be maintained for a long period of time. Further, intrusion of dust can be more effectively prevented than in the conventional dust seal using only the lip portion 66.

As described above, when the outer peripheral surface of the shaft 128 is fitted into the seal member 6 and the lip portion 66 is elastically expanded radially outward by the outer peripheral surface of the shaft 128, the outer periphery of the lip portion 66 The surface 69 is pressed against the inner peripheral surface 7a of the elastic ring body 7. The outer peripheral surface 69 of the lip portion 66 is formed so as to be inclined at an inclination angle θ1 in a direction approaching the axis L of the seal member 6 and the inner peripheral surface 7a of the elastic ring body 7 is inclined at an inclination angle θ2 in a direction approaching the axis L. Since it is formed so as to extend in an inclined manner, and is defined as θ2> θ1, it is possible to always obtain a high surface pressure P (see FIG. 8) appropriate at the sealing surface of the lip portion 66 and at the distal end portion. as a result,
Even if creep and wear occur in the lip portion 66, the initial binding force can be maintained by the elastic compressive force of the elastic ring body 7, and high sealing performance can be maintained for a long time. Further, intrusion of dust can be more effectively prevented than in the conventional dust seal using only the lip portion 66.

In the dust seal 2 described above,
An annular notch 7b having a substantially L-shaped cross section is formed at a corner formed between the inner peripheral surface on the small diameter side (one side of the axis L) of the elastic ring body 7 and the end surface in the axis L direction. I have. With this configuration, the compression allowance h corresponding to the interference allowance provided on the inner peripheral edge portion on the small diameter side of the inner peripheral surface 7a of the elastic ring body 7 can be sufficiently released, and as a result, the shaft 128 of the lip portion 66 The surface pressure P on the outer peripheral surface of the substrate can be set to an appropriate surface pressure P that is neither excessive nor too low (see FIG. 8).

In the dust seal 2 described above,
The elastic ring body 7 is divided into a plurality in the circumferential direction. That is, as described above, the elastic ring members 7 each have twelve elastic arc members 77 having substantially the same configuration.
And they are inserted and attached in a circular arrangement in the annular recess 68. Lip portion 66 is shaft 128
When the outer peripheral surface of the elastic ring 7 is fitted to the outer peripheral surface of the elastic ring 7, the inner peripheral surface of the elastic ring body 7 is radially outward by the compression allowance h. It is enlarged. Since the elastic ring body 7 is divided as described above,
A cantilever force due to bending acts on the notch 7b due to the compression allowance h. As a result, the shaft 128 of the lip 66
A uniform force can always be applied to the seal surface against the outer peripheral surface of the seal surface over the entire circumference thereof and over the entire region of the seal surface in the direction of the axis L. Thus, the surface pressure P of the lip portion 66 against the outer peripheral surface of the shaft 128 can be set to an appropriate surface pressure P that is neither excessive nor excessively small (see FIGS. 9 and 10). Although there is an embodiment in which the elastic ring body 7 is integrally formed, an excessively large elastic force may be generated on the inner peripheral surface on the side of the notch 7b due to the action of the hoop force. It is preferable to be configured to be divided into individual pieces.

When the shaft 128 is inserted into the bearing 126 and assembled, the inner peripheral surface of the main body 94 of the auxiliary seal member 9 is pressed against the outer peripheral surface of the shaft 128 and the lip portion 66 of the seal member 6 is pressed. An annular gap S1 is formed between the inner peripheral surface of the shaft 128, the outer peripheral surface of the shaft 128, and the side surface of the inner peripheral edge of the main body portion 94 on the lip portion 66 side. The gap S1 is formed in the through hole 96 of the main body 94 (or the through hole 96).
Through each of the slits (not shown)
It is configured to communicate with a gap S2 formed between the inner peripheral surface of the shaft 26 and the outer peripheral surface of the shaft 128. Therefore, as described above, when grease is injected from an injection hole (not shown) of the boss portion 124, the grease flows from a through hole (not shown) of the bearing 126 through a groove (not shown) of the bearing 126 to connect the bearing 126 and the shaft 128. Is supplied to the gap S2. The grease thus injected is filled in the gap S1 through each of the through holes 96 in the main body 94 of the auxiliary seal member 9 and by bending (elastic deformation) of the inner peripheral edge of the main body 94. The inclination to one side in the direction of the axis L formed on the inner peripheral edge portion of the main body portion 94 facilitates the deflection at the time of grease injection, and allows the grease to smoothly flow into and fill the gap S1. Each of the through holes 96 (or a slit (not shown) replacing the through hole 96) functions as a grease passage.

By providing the auxiliary seal member 9 as described above, grease can be interposed (reserved) in the gap S1 and thus directly inside the sealing surface of the lip portion 66 in the direction of the axis L. 6 can reduce the coefficient of friction of the sealing surface at the lip 66, thereby reducing its wear. Therefore, even when a bearing for a long-time greasing interval is mounted as a bearing, its friction coefficient can be kept low, and wear can be reduced. Since the surface pressure P of the lip 66 is higher than the surface pressure of the conventional dust seal only of the lip 66 due to the elastic ring body 7, the sealing surface of the lip 66 is required to reduce the wear of the lip 66. Although it is necessary to supply grease, the provision of the auxiliary seal member 9 as described above sufficiently achieves such a lubricating effect. Furthermore,
Grease axis L directly from bearing 126 side to lip 66
Since the pressure in the direction is prevented from acting (it also has a weir function), excessive leakage of the grease from the sealing surface of the lip 66 is prevented.

At the inner peripheral edge of the auxiliary seal member 9, the end face on the side of the lip 66 is attached to the lip 6 from the end face.
A plurality of blade portions 97 extending in six directions are formed at intervals in the circumferential direction. With such a configuration, when relative rotation occurs between the auxiliary seal member 9 and the shaft 128, a flow and a pumping action occur in the grease stored in the gap S1 (arrow f in FIG. 8 indicates the flow of the grease). Direction). As a result, the grease accumulated in the gap S1 is positively moved toward the sealing surface of the lip portion 66, and the grease spreads evenly over the entire sealing surface, and the lubrication effect of the sealing surface of the lip portion 66 is promoted. This makes it possible to more effectively reduce wear.

In the dust seal 2, the elastic ring 7 is fitted and held in the recess 68 of the seal member 6, and the outer surface in the axial direction of the elastic ring 7 is held by the holding flange 84 of the holding ring 8. Since most of it is held down and thus covered, the recess 68 is substantially filled by the elastic ring body 7 so that there is substantially no conventional open-out recess (recess). As a result, it is completely prevented that sediment accumulates in the recess 68 as in the prior art, and the accumulated sediment is also prevented from penetrating from the sealing surface of the lip 66 of the seal member 6 as in the prior art. Durability is ensured.

The lip portion 66 can be prevented from being damaged when the shaft 128 is assembled due to the fact that the concave portion does not substantially exist in the seal member 6. In other words, the dust seal 2 mounted on the left boss 124 in FIG. 2 is symmetrically positioned in the direction of the axis L with respect to the dust seal 2 mounted on the right boss 124. Therefore, in the dust seal 2 attached to the left boss portion 124 in FIG.
In a direction away from the end surface of the bearing 126 (FIG. 2)
2 to the left) and tilted in a direction approaching the axis L, while the shaft 128 is
Is assembled by being inserted from left to right in the direction of the axis L. For this reason, when the shaft 128 is inserted into the bearing 125 through the lip portion 66 of the seal member 6 of the dust seal 2 on the left side in FIG. 2 (when assembled), the tip of the shaft 128 (the right end in FIG. Lip part 6
If the lip 66 is eccentrically hit near the recess 68, and if there is an annular recess outside the lip 66 in the radial direction as in the prior art, the lip 66 may be easily inverted and damaged. Seal member 6 of dust seal 2 of the invention
In this case, the recess 68 is filled with the elastic ring body 7 and becomes substantially nonexistent, so that the portion of the recess 68 serves as a guide, and the shaft 128 can be moved without damaging the lip 66.
Is inserted.

FIG. 11 shows another embodiment of the dust seal 2 according to the present invention. In this embodiment, the seal member 6 includes a main body 64 and a lip 66, and does not include the cylindrical portion 62 in the previous embodiment. Therefore, in the sealing member 6, the outer peripheral surface of the main body 64 is formed on the inner peripheral surface of the cylindrical portion 42 of the reinforcing ring 4, and the other surface of the main body 64 in the direction of the axis L (opposite to the recess 68 in the direction of the axis L). The surface of the flange portion 44 of the reinforcing ring 4 on the side of the cylindrical portion 42 of the flange portion 44 and the other side of the lip portion 66 from the main body portion 64 in the direction of the axis L by the thickness of the flange portion 44 of the reinforcing ring 4. The outer peripheral surface of the protruding end is a flange 4
By being baked on the inner peripheral surface of the reinforcing ring 4, it is integrally fixed to the reinforcing ring 4. The annular concave portion 68 in the above embodiment is formed by the inner peripheral surface of the cylindrical portion 42 of the reinforcing ring 4, one end surface of the main body portion 64 of the seal member 6 in the direction of the axis L, and the outer peripheral surface 69 of the seal member 6. Formed by The elastic ring body 7 is provided with the recess 68 in the same manner as in the previous embodiment.
And is fitted and held on the outer peripheral surface of the lip 66 of the seal member 6. Other configurations are substantially the same as those of the above-described embodiment, and a description thereof will be omitted. As described above, the dust seal 2 has a basic configuration substantially the same as that of the above-described embodiment, except that the configuration of the seal member 6 is slightly different from that of the above-described embodiment. Therefore, FIG.
It is clear that the dust seal 2 shown in FIG. 1 can obtain substantially the same operation and effect as the dust seal 2 in the previous embodiment described with reference to FIGS. 1 to 10, and further description is omitted.

As described above, the present invention has been described in detail based on the embodiments with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and further does not depart from the scope of the present invention. Various other variations or modifications are possible. For example, in the above embodiment, the dust seal 2
Are held integrally with the reinforcing ring 4, the lip 66 and the sealing member 6, the elastic ring 7 fitted in the concave 68, and the elastic ring 7 held in the concave 68. The holding ring 8 and the auxiliary seal member 9 are provided, but there are also embodiments in which the holding ring 8 and the remaining members other than the auxiliary seal member 9 are provided. In the case of this embodiment, between the elastic ring 7 and the recess 68 of the seal member 6, locking means for holding the elastic ring 7 so as not to come out of the recess 68, for example, the outer diameter of the recess 68. And one of an annular locking protrusion or an annular locked groove formed on the outer peripheral surface of the lip portion 66 and the outer peripheral surface and the inner peripheral surface of the elastic ring body 7. It would be necessary to provide a locking means consisting of an annular locking projection or the other of the annular locked grooves. In the case of this embodiment, the dust seal 2 uses the reinforcing ring 4 to make the boss 124
Is mounted on the mounting section 140. Also in this embodiment, the initial tightening force can be maintained even if the lip portion 66 has creeping and wear, since the tightening force on the outer peripheral surface of the shaft 128 is relatively large, and as a result, high sealing performance is maintained. And the effect of preventing sediment accumulation can be achieved. In the case of the embodiment in which the dust seal 2 is formed of the remaining members except for the auxiliary seal member 9, in addition to the above-described effects, it is possible to further prevent the lip portion 66 from being damaged when the shaft 128 is assembled. The effect of is obtained.

In the above embodiment, there is also an embodiment in which the auxiliary seal member 9 is not provided with any of the plurality of through holes 96 or slits (not shown), the inclination of the inner peripheral edge portion, and the blade portion 97. Even in this case, the provision of the auxiliary sealing member 9 forms the gap S1 and stores grease at a position adjacent to the sealing surface of the lip portion 66. Therefore, the lubrication of the sealing surface of the lip portion 66 described above is performed. The effect is obtained. In this connection, an embodiment in which the elastic ring body 7 is integrally formed without being divided is also possible. When the elastic ring body 7 is integrally formed, the surface pressure of the sealing surface of the lip portion 66 may be excessively high as described above. However, by providing the auxiliary sealing member 9 together, the lip 66
Since the lubrication effect of the sealing surface of the lip portion 66 can be improved, the wear of the lip portion 66 can be sufficiently reduced as desired. In the above-described embodiment, the dust seal 2 of the present invention is applied to a bearing portion in which grease is used as a lubricant, but is not limited to this, and may be applied to a bearing portion in which high-viscosity oil is used. Applicable.

[0036]

According to the dust seal of the present invention, the binding force on the outer peripheral surface of the shaft is relatively large, and the initial binding force can be maintained even if creep and wear occur on the lip portion. The sealing property can be maintained. Further, the coefficient of friction of the sealing surface at the lip portion can be reduced, and therefore, its wear can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a hydraulic shovel including a bearing unit having a dust seal according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is an enlarged view of a portion B in FIG. 2;

FIG. 4 is a cross-sectional view partially showing a state where the dust seal shown in FIG. 3 is mounted on a mounting portion of a boss.

FIG. 5 is a partial view of a part of the dust seal shown in FIG. 4 as viewed from the right side in FIG. 4;

FIG. 6 is a perspective view of one elastic arc member constituting the elastic ring body included in the dust seal shown in FIG. 3;

FIG. 7 is an exemplary sectional view showing a part of the dust seal shown in FIG. 4 in an exploded state;

FIG. 8 is an enlarged view of a main part of FIG. 3, for explaining a part of the operation and effect of the present invention.

FIG. 9 is a schematic perspective view partially showing some components of the dust seal shown in FIG. 8, for explaining a part of the operation and effect of the present invention.

FIG. 10 is a perspective view showing a part of the elastic ring body shown in FIG. 9, for explaining a part of the function and effect of the present invention.

FIG. 11 is a view showing another embodiment of the dust seal according to the present invention, and showing the same aspect as FIG. 3;

[Explanation of symbols]

 Reference Signs List 2 dust seal 4 reinforcing ring 6 sealing member 66 lip portion 68 concave portion 7 elastic ring body 7b cutout 8 press ring 9 auxiliary seal member 77 elastic arc member 94 through hole 97 blade portion 124 boss portion 126 bearing 128 shaft L axis

Claims (10)

[Claims] 1. A dust seal comprising a reinforcing ring and an annular sealing member mounted on the reinforcing ring, wherein the sealing member has an annular lip. Is mated and held,
The lip portion, when fitted on the outer peripheral surface of the shaft to be sealed, is brought into pressure contact with the outer peripheral surface of the shaft by the elastic compressive force of the elastic ring body in addition to its own elastic compressive force. And dust seal. 2. An elastic compressive force acting on the outer peripheral surface of the lip portion of the elastic ring body in a state fitted to the outer peripheral surface of the shaft acts on the outer peripheral surface of the shaft of the lip portion. The dust seal according to claim 1, wherein the dust seal is defined to be larger than the elastic compression force. 3. An outer peripheral surface of the lip portion is formed so as to be inclined and inclined at an inclination angle θ1 in a direction approaching the axis of the seal member, and an inner peripheral surface of the elastic ring body is inclined in a direction approaching the axis. The dust seal according to claim 1, wherein the dust seal is formed so as to extend with an inclination of θ2 and is defined as θ2> θ1. 4. An annular notch having a substantially L-shaped cross section is formed at a corner formed between the inner peripheral surface on the small diameter side of the elastic ring body and the axial end surface. The dust seal according to any one of claims 1 to 3. 5. The dust seal according to claim 1, wherein the elastic ring body is divided into a plurality in the circumferential direction. 6. An annular auxiliary seal member mounted on the reinforcing ring so as to be in close contact with an end surface of the seal member on a base side of the lip portion, and an inner peripheral surface of the auxiliary seal member together with the lip portion is provided. When fitted on the outer peripheral surface of the shaft, the inner peripheral surface of the auxiliary seal member is pressed against the outer peripheral surface of the shaft and the inner peripheral surface of the lip portion, the outer peripheral surface of the shaft, and the auxiliary seal member. The dust seal according to any one of claims 1 to 5, wherein an annular gap is formed between the inner peripheral edge portion and a side surface on the lip portion side. 7. The dust seal according to claim 6, wherein an inner peripheral edge portion of the auxiliary seal member extends toward the lip portion side and inclines in a direction approaching the axis. 8. An inner peripheral edge portion of the auxiliary seal member,
8. The dust seal according to claim 6, wherein a plurality of blades extending from the end face in the direction of the lip are formed on the end face on the side of the lip at intervals in the circumferential direction. 9. The dust seal according to claim 6, wherein a plurality of through holes or slits are formed at an inner peripheral edge of the auxiliary seal member at intervals in a circumferential direction. 10. A dust seal including a reinforcing ring and an annular sealing member mounted on the reinforcing ring, wherein the sealing member is fitted and held on an outer peripheral surface of the lip portion. Elastic ring body,
An annular auxiliary seal member attached to the reinforcing ring,
When the seal member and the auxiliary seal member are fitted to the outer peripheral surface of a shaft to be sealed, the lip portion of the seal member
In addition to its own elastic compressive force, the elastic compressive force of the elastic ring body is pressed against the outer peripheral surface of the shaft, the inner peripheral surface of the auxiliary seal member is pressed against the outer peripheral surface of the shaft, and the lip is A dust seal, wherein an annular gap is formed between an inner peripheral surface of the portion, an outer peripheral surface of the shaft, and a side surface of the auxiliary seal member on the inner peripheral edge side of the lip portion.