JPH11223223A - Cup seal for needle bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maximize the life by suppressing decrease in a contact area having sufficient contact pressure to the curved surface of a neck part even though abrasion by sliding friction with the curved surface of the neck part progresses. SOLUTION: In the radial lip 24 of this cup seal 21, which is brought into contact with the neighborhood of the starting end of the curved surface 12 of the neck part of the spider shaft 3 of an universal joint, a thinned part 24a for flexing is arranged just before a position being a contact starting end to the curved surface 12 of the neck part so that an end side beyond the position being the contact start end is easily bent along the curved surface 12 of the neck part, and also the thickness of the end side being a contact terminal to the curved surface 12 of the neck part is arranged thicker than the thinned part 24a for flexing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needle bearing which is externally fitted to a spider shaft constituting a universal joint and which is attached to an inner peripheral surface of an end portion of a case to prevent intrusion of contaminants into the case and to prevent contamination of the case. The present invention relates to a needle bearing cup seal that serves to store and retain filled lubricating grease.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional example of the above-described needle bearing cup seal. The cup seal 1 is attached to an inner peripheral surface of an end portion of a case (outer ring) 6 of a needle bearing which is fitted through a needle roller 4 to an outer periphery of a spider shaft 3 constituting a universal joint such as a propeller shaft of an automobile. Thus, it prevents the entry of contaminants such as muddy water into the case 6 and stores and retains the lubricating grease filled in the case 6.

As shown in the figure, the cup seal 1 has a metal annular core 8 attached to the inner peripheral surface of the end of the case 6, and an elastic material fixed to the inner periphery of the annular core 8. And a seal body 10. The seal body 10 is provided on the neck curved surface 1 of the spider shaft 3.
A radial lip 14 in which the tip comes into contact with the vicinity of the starting end of the spider shaft 3 in an elastically deformed state;
And a side lip 15 at a position close to the terminal end, the tip of which contacts in an elastically deformed state.

The neck curved surface 12 is generally an arc surface (R surface) gradually rising from the outer periphery of the spider shaft 3. Further, the radial lip 14 of the seal body 10 described above is used.
In the natural state before being mounted on the spider shaft 3 at a predetermined position, the side lip 15 has a protruding length or a protruding portion such that a part of the distal end protrudes from the neck curved surface 12 as shown in FIG. The angle has been set. In this manner, the protrusion length and the protrusion angle of each lip are set to be larger than the dimensions of the mounting space of the cup seal 1 in the actual use state, as shown in FIG. This is to ensure that the contact pressure required for the required sealing performance is brought into contact with the predetermined position of the neck curved surface 12 in the state of being performed.

Conventionally, FIG. 7 and FIG.
As shown in the publication No. 77453 and the like, the respective lips 14 and 15 gradually increase in wall thickness toward the distal end so that the distal end flexes flexibly and the adhesion to the neck curved surface 12 is enhanced. Is reduced.

With the above configuration, the cup seal 1 is provided.
In the use state, as shown in FIG.
A seal wall for preventing intrusion of muddy water or the like into the inside is formed by the side lip 15 and the radial lip 14 so as to be doubled to enhance the reliability of the seal. In addition, around the needle rollers 4 in the case 6, at the time of maintenance and inspection, for example, lubricating grease is supplied through a lubricating oil supply groove or the like provided on the left end side (not shown) of the spider shaft 3. Filling and refilling are performed.

[0007] By filling and replenishing new lubricating grease, old lubricating grease and excess lubricating grease remaining in the case 6 are pushed out toward the lips 14 and 15 by the filling pressure, and each lip is dispensed. The lips 14 and 15 are flexed and discharged between the lips 14 and 15 and the neck curved surface 12 to the outside. The space formed between the radial lip 14 and the side lip 15 functions as a grease reservoir 17, and lubricating grease accumulated in the grease reservoir 17 is provided on each of the lips 14, 15 and the neck curved surface. 12 to reduce the sliding friction.

[0008]

By the way, each lip 1
In parts 4 and 15, the portions in contact with the neck curved surface 12 wear more due to sliding friction with the neck curved surface 12, and as shown in FIG. . This abrasion is particularly severe at the distal end of the radial lip 14 where a radial load is applied while sliding against the spider shaft 3 at high speed and a thrust load acts on the neck curved surface 12 depending on the axial dimensional tolerance and the like. Become. For example, the tip of the radial lip 14 has a thickness of t1 as shown in FIG. 8 when it is new, but is shown by t2 in FIG. 9 due to abrasion due to sliding friction with the neck curved surface 12. As described above, the thickness gradually decreases (Δt shown in FIG. 9 is a decrease due to wear).

When the thickness t2 of the tip becomes less than a certain value, the tip is easily turned up due to the pressure of muddy water invading from the outside or the vibration generated by sliding on the neck curved surface 12, As a result, the contact area having a good contact pressure decreases from S1 shown in FIG. 8 to S2 shown in FIG.
This leads to a decrease in sealing performance. In the case of the conventional cup seal 1 described above, since the thickness of each lip 14, 15 gradually decreases toward the tip, the tip of the radial lip 14 is worn down to a certain thickness or less. The problem is that the time is short, the service life is short, and replacement is required early.

[0010] Even when the lips 14 and 15 are new, the portions that are in contact with the neck curved surface 12 are:
Due to variations in dimensions of the spider shaft 3, an appropriate contact force is not always ensured. For example, the tip of the radial lip 14 has a good contact pressure in the contact area S1 as shown in FIG. 8 if the spider shaft 3 is manufactured with a predetermined size. However, when the neck curved surface 12 of the spider shaft 3 is shifted outward in the axial direction, the contact area of the radial lip 14 with the neck curved surface 12 decreases. Further, the radial lip 14 has a structure in which the wall thickness decreases toward the distal end, so that it is impossible to obtain a good contact pressure, and the pressure of muddy water intruding from the outside and the sliding with the neck curved surface 12 are reduced. Due to the vibration generated in the above, the front end portion is easily turned up and the sealing performance is lowered.

Therefore, an object of the present invention is to solve the above-mentioned problem, and even if wear due to sliding friction with the curved surface of the neck progresses, the tip of the radial lip is unlikely to be turned up by external pressure or vibration. It can be maintained for a long time to a certain degree or more, and even if the dimensions of the spider shaft vary, the tip of the radial lip is unlikely to be turned up by external pressure or vibration, and it can maintain a good contact state with the curved surface of the neck, Another object of the present invention is to provide a cup seal for a needle bearing which can suppress a decrease in a contact area having a good contact pressure with a curved surface of a neck and can prolong a life.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to provide a metal annular core attached to an inner peripheral surface of an end portion of a needle bearing case which is fitted to a spider shaft constituting a universal joint; A radial lip, the tip of which is elastically deformed in the vicinity of the start end of the neck portion curved surface of the spider shaft, the seal body being provided with a seal body made of an elastic material fixed to the inner periphery of the body; In a needle bearing cup seal having a side lip with which the tip portion contacts in an elastically deformed state at a position near the end of the neck curved surface of the neck, at least the radial lip includes:
In front of a position where the spider shaft comes into contact with the neck curved surface, a flexible thin portion for facilitating bending of the distal end side along the neck curved surface is provided, and the neck has This is achieved by a needle bearing cup seal characterized in that the thickness of the tip end, which is the terminal of contact with the curved surface, is made thicker than the flexible thin portion.

[0013] According to the above configuration, the radial lip is easy to bend its tip side along the neck curved surface before the position where the spider shaft comes into contact with the neck curved surface. To have a thin portion for flexibility,
A long contact area for contacting the neck curved surface 12 with a good contact pressure can be secured on the distal end side of the flexible thin portion, and sealing performance can be improved.

Since the tip is thickened, the tip of the radial lip may be exposed to the pressure of muddy water that enters from outside or the neck may be bent even if the wear due to sliding friction with the curved surface of the neck progresses. It is possible to extend the period of wear to a certain level or less, at which the sheet is easily turned up by the vibration generated by the sliding of. In other words, the thickness of the distal end of the radial lip can be maintained for a long period of time at a certain level or more where turning over due to external pressure or vibration is unlikely to occur, thus suppressing a decrease in the contact area having a good contact pressure on the neck curved surface. Thus, excellent sealing performance can be maintained for a long period of time, and the life can be prolonged.

In addition, since the tip portion is thickened, even if the spider shaft varies in size, the tip of the radial lip vibrates due to the pressure of muddy water penetrating from the outside or sliding with the curved surface of the neck. No longer easily flip up. That is, by increasing the thickness of the tip of the radial lip, the contact pressure at the tip can be increased,
Good contact pressure can be obtained on the neck curved surface, and excellent sealing performance can be maintained.

[0016] The radial lip may have a protrusion on the opposite side of the distal end portion from the neck curved surface, and the protrusion may increase the thickness of the distal end portion. In this way, only a part of the tip of the lip is thickened,
The middle part of the contact area on the tip side of the lip, which is less related to turning up, can avoid thickening, so that the elastic deformation of the lip tip side does not sacrifice the adhesion to the curved surface of the neck. In addition, the effect of thickening can be enjoyed, and at the same time, material can be saved.

[0017] Preferably, the entire surface of the radial lip on the neck curved surface side located on the distal end side of the flexible thin portion is formed into a smooth arc surface.
With this setting, it is possible to reduce the amount of elastic deformation of the portion in contact with the neck curved surface, and the contact pressure of the radial lip against the neck curved surface is mainly due to the elastic deformation of the flexible thin portion. Since the flexible thin portion itself does not wear due to contact with the curved surface of the neck, the initially set contact pressure can be stably maintained for a longer period, and the sealing performance can be improved. Can be improved in reliability.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a needle bearing cup seal according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 show a first embodiment of a cup seal for a needle bearing according to the present invention. The needle bearing cup seal 21 according to the first embodiment is provided with a needle roller 4 on the outer periphery of a spider shaft 3 constituting a universal joint such as a propeller shaft of an automobile.
Needle bearing case (outer ring)
Attached to the inner peripheral surface of the end of the case 6, it functions to prevent intrusion of contaminants such as muddy water into the case 6 and to store and retain lubricating grease filled in the case 6.

As shown, the cup seal 21 is
An annular core 8 made of metal is attached to the inner peripheral surface of the end of the case 6, and a seal body 23 made of an elastic material is fixed to the inner periphery of the annular core 8. The seal body 23 has an elastically deformed radial lip 24 near the beginning of the neck curved surface 12 of the spider shaft 3 and an elastically deformed state near the end of the neck curved surface 12. And has a side lip 25 with which the front end contacts.

The neck curved surface 12 is usually an arc surface (R surface) gradually rising from the outer periphery of the spider shaft 3. Further, the radial lip 24 of the seal body 23 described above is used.
In a natural state before being mounted on the predetermined position of the spider shaft 3, the side lip 25 has a protruding length or a protruding portion such that a part of the tip protrudes from the neck curved surface 12 as shown in FIG. The angle has been set. In this manner, the protrusion length and the protrusion angle of each lip are set to be larger than the dimensions of the mounting space of the cup seal 21 in the actual use state, as shown in FIG. This is to ensure that the contact pressure required for the required sealing performance is brought into contact with the predetermined position of the neck curved surface 12 in the state of being performed.

In the case of the present embodiment, the radial lip 24 is attached to the neck curved surface 12 of the spider shaft 3.
Before the position P1 which is the contact start end of the cervical portion, a flexible thin portion 24a for facilitating bending of the distal end side along the cervical portion curved surface 12 is provided.
The thickness t3 on the tip end, which is the terminal of contact with the second portion 2, is made thicker than the thickness t4 of the flexible thin portion 24a.

In the cup seal 21 described above, the radial lip 24 has a flexible thin portion 24a provided short of a position P1 which is a contact start end with the neck curved surface 12, as shown in FIG. The bending of the neck portion 12 causes the neck curved surface 12
And a long contact area S3 for making contact with a good contact pressure can be secured, and the sealing performance can be improved.

Since the tip is thickened, as shown in FIG. 3, even if the thickness of the tip is reduced by .DELTA.t due to abrasion due to sliding friction with the neck curved surface 12, the tip remains thick. The tip of the radial lip 24 has a thickness t5 sufficient to prevent the tip of the radial lip 24 from being turned up by the pressure of muddy water penetrating from the outside or the vibration generated by sliding with the neck curved surface 12, and the like. Below a certain level (for example, the thickness t in FIG. 9), which is easily turned up by the pressure of muddy water invading from the outside or the vibration generated by sliding with the neck curved surface 12.
2) It is possible to extend the period of wear.

That is, the distal end of the radial lip 24 can be maintained for a long period of time beyond a certain level where it is unlikely to be turned up by an external pressure or vibration. By maintaining the initial long contact area S3 for a long time, it is possible to maintain excellent sealing performance for a long time,
The life can be extended.

In addition, since the tip portion is thickened, even if the spider shaft 3 is displaced axially outward due to dimensional variations, an appropriate state of contact with the neck curved surface 12 is maintained. It can be prevented from being turned up by the pressure of muddy water invading from the outside, the vibration generated by sliding with the neck curved surface 12, and the like, and therefore, it is possible to have a good contact pressure with the neck curved surface 12. .

FIGS. 4 to 6 show a second embodiment of a cup seal for a needle bearing according to the present invention. The cup seal 27 according to the second embodiment includes a metal annular core 8 fitted to the inner periphery of the end of the case 6 of the needle bearing, and a seal body 28 made of an elastic material attached to the annular core 8. Consists of The seal body 28 has a radial lip 29 that makes the distal end thereof come into contact with a position near the start end of the neck curved surface 12 of the spider shaft 3 and a tip that comes into contact with a position near the end of the neck curved surface 12. The configuration including the side lip 25 and the configuration other than the radial lip 29 are the same as those of the cup seal 21 of the first embodiment described above.

Radial lip 24 in the first embodiment
Was a mode in which the thickness gradually increased from the flexible thin portion 24a toward the distal end. However, in the radial lip 29 of the second embodiment, a projection 30 is provided on the side opposite to the neck curved surface 12 at the tip end which is the end of contact with the neck curved surface 12. Part thickness t
6 is thicker than the thickness t7 of the flexible thin portion 29a on the base end side.

The flexible thin portion 29a corresponds to the flexible thin portion 24a in the first embodiment.
The spider shaft 3 is set slightly before the position P1 at which the spider shaft 3 comes into contact with the neck curved surface 12, and a portion closer to the distal end than the flexible thin portion 29a extends along the neck curved surface 12. It is slightly thinner than the surroundings to make it easier to bend.

FIG. 4 shows the cup seal 2 of the second embodiment.
7 shows a state before elastic deformation of each lip 25, 29. In FIG. 5, the tip of each lip 25, 29 is elastically deformed and is in contact with the neck curved surface 12 of the spider shaft 3, and the initial contact area S of the radial lip 29 is shown in FIG.
5 is shown. In FIG. 6, the neck curved surface 12 is shown.
5 shows a state in which each of the lips 25 and 29 is worn by the sliding friction with the above, the decrease Δt in the thickness of the tip of the radial lip due to the wear, and the remaining thickness t8.

Also in the second embodiment, as in the first embodiment, a long contact area S6 for contacting the neck curved surface 12 with a good contact pressure can be secured, and the sealing performance can be improved. In addition, by maintaining the distal end of the radial lip 29 for a long period of time at a certain level or more where it is unlikely to be turned up by external pressure or vibration, an initial contact pressure against the neck curved surface 12 can be obtained. By maintaining the long contact area S6 for a long period of time, excellent sealing performance can be maintained for a longer period, and the life can be extended.

In the case of the second embodiment, only a part of the tip of the lip is thickened.
The middle portion of the contact area on the tip side of the lip, which is less related to turning up, can avoid thickening, so that the elasticity of the lip tip side does not sacrifice the adhesion to the neck curved surface 12. In addition, the effect of thickening can be enjoyed, and at the same time, material can be saved. Even if the spider shaft 3 is displaced to the outside in the axial direction due to variation in dimensions, the tip portion is thickened as in the first embodiment, so that the spider shaft 3 has a good contact pressure against the neck curved surface 12. be able to.

The radial lips 24 and 29 in each of the above embodiments are, as shown in FIGS.
Before the spider shaft 3 comes into contact with the neck curved surface 12 and is elastically deformed, the spider shaft 3 is formed in a shape in which the contact area extends straight. However, the contact area at the tip of the radial lip is
The curved shape (curved shape shown in FIGS. 2 and 5) that is substantially equal to the curved state of the neck curved surface 12 even when not elastically deformed may be formed.

In this manner, the amount of elastic deformation of the portion that comes into contact with the neck curved surface 12 can be reduced, and the contact pressure of the radial lip 24 on the neck curved surface 12 mainly depends on the thickness of the flexible thin wall. Since the flexible thin portion itself does not wear due to contact with the neck curved surface 12, the initially set contact pressure can be stably maintained for a longer period of time. And the reliability of the sealing performance can be improved.

In each of the above-described embodiments, the side lip 25 has the conventional structure. However, the side lip is provided with a flexible thin portion like the radial lips 24 and 29 and has a tip portion. May be made thicker than the flexible thin part. By doing so, it is possible to further improve the sealing performance and extend the life of the side lip.

[0035]

According to the cup seal for a needle bearing of the present invention, the radial lip has its distal end side closer to the neck bending before the position where the spider shaft comes into contact with the neck bending surface. It has a thin portion for flexibility to make it easy to bend along the surface, and secures a long contact area that contacts the neck curved surface 12 with a good contact pressure on the tip side from the thin portion for flexibility. And sealing performance can be improved.

Since the tip portion is thickened, even if wear due to sliding friction with the neck curved surface progresses, the tip of the radial lip may be exposed to the pressure of muddy water invading from the outside or the neck curved surface. It is possible to extend the period of wear to a certain level or less, at which the sheet is easily turned up by the vibration generated by the sliding of. In other words, the distal end of the radial lip can be maintained for a long time at a certain level or more where turning over is unlikely to occur due to external pressure or vibration. The sealing performance can be maintained for a longer period, and the life can be extended.

Even if the curved surface of the cervix shifts outward in the axial direction due to variations in the dimensions of the spider shaft, the distal end portion of the radial lip is thickened without reducing the contact force. , A good contact pressure is obtained, and excellent sealing performance can be maintained.

The radial lip has a projection on the opposite end of the tip from the curved surface of the neck, and if the thickness of the tip is increased by the projection, the radius of the tip of the lip can be increased. Since only a part of the lip is thickened, the middle part of the contact area on the tip side of the lip, which is less related to turning up, can be prevented from being thickened. Without sacrificing adhesion to the curved surface,
The effect of thickening can be enjoyed, and at the same time, material can be saved.

In addition, the neck located closer to the distal end than the flexible thin portion of the radial lip such that the distal end of the radial lip is in good contact with the curved surface of the neck over a wider area. When the entire surface on the curved side of the neck is formed into a smooth arcuate surface, the amount of elastic deformation of the portion in contact with the curved side of the neck can be reduced, and the contact pressure of the radial lip against the curved side of the neck can be reduced. Is mainly set by the elastic deformation of the flexible thin portion, and since the flexible thin portion itself does not wear due to contact with the curved surface of the neck, the initially set contact pressure is increased. Stability can be maintained for a long time, and the reliability of the sealing performance can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a positional relationship between a first embodiment of a cup seal for a needle bearing according to the present invention and a universal joint to which the cup seal is attached.

FIG. 2 is a sectional view of a main part showing a state in which the cup seal according to the first embodiment of the present invention shown in FIG. 1 is attached to a universal joint.

FIG. 3 is a sectional view of a main part of the universal joint showing a state in which each lip of the cup seal of the first embodiment of the present invention shown in FIG. 1 is slid and worn.

FIG. 4 is a sectional view of a main part showing a positional relationship between a second embodiment of a cup seal for a needle bearing according to the present invention and a universal joint to which the cup seal is attached, and the like.

FIG. 5 is a cross-sectional view of a main part showing a state in which the cup seal according to the second embodiment of the present invention shown in FIG. 4 is attached to a universal joint.

FIG. 6 is a sectional view of a main part of the universal joint showing a state in which each lip of the cup seal according to the second embodiment of the present invention shown in FIG. 4 is slid and worn;

FIG. 7 is a sectional view of a main part showing a positional relationship between a conventional needle bearing cup seal and a universal joint to which the cup seal is attached.

FIG. 8 is a sectional view of a main part showing a state in which a conventional cup seal is attached to a universal joint.

FIG. 9 is a cross-sectional view of a main part of a universal joint showing a state in which each lip of a conventional cup seal is slid and worn.

[Explanation of symbols]

 Reference Signs List 3 spider shaft 4 needle roller 6 case (outer ring) 8 annular core body 12 neck curved surface 21 cup seal 23 seal body 24 radial lip 24a flexible thin portion 25 side lip 27 cup seal 28 seal body 29 radial lip

Claims (1)

[Claims] 1. A metal annular core attached to an inner peripheral surface of an end portion of a needle bearing case which is fitted onto a spider shaft constituting a universal joint, and an elastic material fixed to an inner periphery of the annular core. A radial lip, the tip of which is in an elastically deformed state near the beginning of the neck curved surface of the spider shaft, and the seal body is elastically located at a position close to the end of the neck curved surface of the spider shaft. In a cup seal for a needle bearing having a side lip with which a tip portion contacts in a deformed state, at least the radial lip is located before a position where the spider shaft comes into contact with a curved surface of a neck portion. Also has a flexible thin portion for facilitating bending of the distal end side along the curved surface of the neck, and the thickness of the distal end, which is the terminal of contact with the curved surface of the neck, is set to the above-mentioned range. Cup sealing needle bearing, characterized in that the thickening than use the thin portion.