JPH083710Y2 - Self-aligning seal structure for ball bearings with tilt function - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a seal structure for a rolling bearing that automatically aligns with the inclination of the inner and outer rings to prevent intrusion of muddy water or dust into the inside of the bearing.

[Conventional technology]

Bearings used in joints such as drive shafts of automobiles are required to have a centering function that automatically absorbs the inclination between the inner and outer wheels in order to cope with the inclination of the shaft that occurs during traveling. Therefore, in the conventional bearing,
A ball bearing is generally used in which the radius of curvature of the ball rolling surface in the groove width direction is set to be considerably larger than the radius of the ball, and the gap between the inner and outer races is increased to increase the working angle.

By the way, since the joint part of the drive shaft is arranged on the bottom surface of the vehicle body of the automobile, it is easily affected by muddy water, rainwater, dust, etc. during running. Along with the core function, a seal structure is required to prevent the intrusion of muddy water into the interior.

FIGS. 4 to 6 show a conventional example in which a ball bearing having the above-mentioned centering function is provided with a special seal structure for preventing intrusion of muddy water or the like. This seal structure is roughly classified into a non-contact type using a labyrinth gap as shown in FIG. 4 and a contact type using a contact lip as shown in FIGS. 5 and 6.

In the example of FIG. 4, bearing seals 4 for enclosing lubricating grease inside are attached to both sides of the ball rolling surface 3 between the inner ring 1 and the outer ring 2, and a metal shield plate 20 is provided outside the bearing seals 4.
A labyrinth gap 22 is formed between the outer diameter end of the shield plate 20 and the grooves 21 at both ends of the outer ring 2 to prevent intrusion of muddy water, dust and the like.

The bearing seal 4 is made of an elastic material such as rubber on the surface of the core metal 4a.
4b is attached to form an outer surface, and an inner peripheral end of the outer surface is slidably brought into contact with an outer diameter surface of the inner ring 1 to form a lip portion.

On the other hand, in the contact type example of FIG. 5, an annular lip 24 protruding outward is formed on the outer surface of the bearing seal 23, and the tip of the lip 24 is slid on the inner surface of the shield plate 25. It has a structure that prevents it from coming in contact with muddy water.

The example of FIG. 6 has the same basic structure as that of FIG. 5, but an annular recess 27 is formed on the inner surface of the shield plate 26, and a lip 29 is formed on the inclined surface 28 inside the recess 27. The difference is that the tip of the slide contact. In this case, the protruding direction of the lip 29 and the inclined direction of the inclined surface 28 intersect each other, and the lip 29 is attached in a state of being bent outward along the inclined surface 28.

In FIG. 4, 18 is a ball as a rolling element,
Reference numeral 19 indicates a cage for holding the ball 18.

[Problems to be solved by the device]

However, in the structure of FIG. 4, when the axes of the inner ring 1 and the outer ring 2 are tilted, the gap between the groove 21 of the outer ring 2 and the outer diameter end of the shielding plate 20 is changed, and the labyrinth gap 22 is changed, so that the stability is stable. There is a drawback that the labyrinth effect is not obtained.

Further, in order to improve the labyrinth effect, it is necessary to increase the length of the labyrinth gap. However, in the above structure, it is necessary to prevent the outer ring 2 and the shield plate 20 from interfering with each other when the inner and outer rings are tilted. The length l _{2 of} 22 is limited to the width of the groove 21 of the outer ring 2 and cannot be made large,
Therefore, there is a drawback that the labyrinth effect is not sufficiently obtained. The labyrinth effect can be improved by making the shape of the gap 22 complicated, but such a complicated structure has a drawback of increasing space and processing cost.

On the other hand, in the structure of FIG. 5, when the inner ring and the outer ring are inclined, the distance between the shield plate 25 fixed to the inner ring 1 and the bearing seal 23 fixed to the outer ring 2 is different in the axial direction and the radial direction of the bearing. Therefore, if the amount of interference of the lip 24 with respect to the shield plate 25 is small, a gap is created between the lips to allow muddy water to enter. However, conversely, if the amount of interference is increased to prevent a gap, the frictional force between the lip 24 and the shielding plate 25 increases, which causes a problem that rotational torque and heat generation increase.

Further, in the structure of FIG. 6, the change in the tightening amount of the lip 29 due to the inclination of the inner and outer races 1 and 2 is relatively small as compared with the example of FIG. 5, but the lip bent outward along the inclined surface 28. When the shield plate 26 is mounted or when the bearing is pushed by the inclined surface 28 during rotation of the bearing, the tip of 29 is subjected to inward compressive stress, and the outer peripheral edge is deformed inward by the stress and the wavy as shown in FIG. May cause phenomena. When such a phenomenon occurs, there is a drawback in that a gap 30 is formed between the inclined surface 28 and the indentation formed on the outer peripheral edge of the lip 29.

This invention has been made in order to solve the above-mentioned drawbacks of the prior art. The first problem is that the labyrinth length can be increased and the sealing effect can be improved in a non-contact type seal structure. To provide a different structure.

The second problem is that in the contact-type seal structure,
It is to provide a seal structure that exhibits stable sealing performance regardless of the amount of tilt of the inner and outer rings.

[Means for solving the problem]

In order to solve the above-mentioned first problem, the present invention forms the rolling surfaces of the inner ring and the outer ring with a radius of curvature larger than the radius of the ball incorporated between them, and the outer surfaces are formed on both sides of each rolling surface. In a self-aligning seal structure of a ball bearing having a tilt function in which a bearing seal made of an elastic material and a metal shield plate are sequentially provided from the inside, the shield plate is fixed to the inner ring and the inner shield plate and the outer ring. An outer shield plate to be fixed, and the free ends of both shield plates have an arc centered on the bearing center in the cross section parallel to the axis including the bearing center, or the inclination of the tangent to the arc. The structure adopts a structure in which the labyrinth gaps are formed between the bent parts by bending them so as to face each other.

Further, in order to solve the second problem, the rolling surfaces of the inner ring and the outer ring are formed with a radius of curvature larger than the radius of the ball incorporated between them, and the outer surface is made of elastic material on both sides of each rolling surface. In a self-aligning seal structure of a ball bearing having a tilt function in which a bearing seal and a metal shield plate are sequentially provided from the inside, the above-mentioned shield plate is an inner shield plate fixed to the inner ring and an outer side fixed to the outer ring. And a shield plate, and a lip that continuously projects on the circumference is formed on the outer surface of the bearing seal, and the free end portion of the inner shield plate is a sliding contact surface where the tip of the lip slides. Is formed, and the sliding contact surface is inclined at an angle of a tangent to an arc centered on the bearing center in a cross section parallel to the shaft center including the bearing center, and the free end portion of the outer shield plate and the sliding contact surface are slanted. Slightly between the outer edge of the contact surface To adopt provided with a gap structure.

[Action]

In the first means for achieving the first object, the positions of the bent portions of the inner shield plate and the outer shield plate are set so as not to interfere with the inner and outer rings, and the length of the labyrinth clearance formed in the bent portions does not contact the bearing seal. Set up to the range.

When the amount of displacement inside the bearing when the inner and outer rings are tilted is taken, the amount of displacement is proportional to the distance from the center of the bearing, and becomes smaller the closer to the center of the bearing. Therefore, when comparing the displacement of the forming portion of the labyrinth gap between the structure of the present application and the conventional structure of FIG. 4, the forming portion of the present structure is closer to the bearing center than the conventional structure in which the forming portion is located at the inner diameter of the outer ring. The amount of displacement is reduced, and therefore the length of the labyrinth gap of the present invention can be increased by the amount of reduction in the amount of displacement.

Also, by making each bent portion an arc surface centered on the bearing center or an inclined surface in the tangential direction thereof, the length of the bent portion can be increased as compared to the case where the shape is parallel to the center line of the bearing. Yes, the labyrinth gap is longer and the sealability is improved.Both bends move on the same trajectory even when the inner and outer rings are tilted, so the labyrinth gap is always kept constant and a stable labyrinth effect is obtained. .

On the other hand, in the second means for achieving the object, both the tip of the lip and the sliding contact surface are inclined at the angle of the tangent of an arc centered on the bearing center, so that when the inner and outer rings of the bearing are inclined, the sliding contact is made. The surface is displaced along its slope. Moreover, since the lip slides on the sliding contact surface following the protruding direction, almost no compressive stress acts on the tip of the lip, and the contact state between the lip and the sliding contact surface is always the same. Kept in.

Further, by providing a required gap between the free end portion of the inner shield plate and the outer end portion of the outer shield plate sliding contact surface,
Rainwater, earth and sand, etc. are prevented from being directly added to the bearing seal, and the sealability is improved.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.

In the following embodiments, the same parts as those in the structures shown in FIGS. 4 to 6 are designated by the same reference numerals and the description thereof will be omitted.

FIGS. 1 (a) and 1 (b) show an embodiment of a non-contact type seal structure. In this bearing, between the inner ring 1 and the outer ring 2 both ends, the inner shield plate 5 and the inner shield plate 5 face each other. An outer shield plate 6 is attached. Both shield plates 5 and 6 are
The metal thin plate is formed in an annular shape, and the inner peripheral edge and the outer peripheral edge are press-fitted and fixed in the grooves 7 and 8 provided in the inner ring 1 and the outer ring 2, respectively.

The free ends of the two shield plates 5 and 6 face each other substantially at the center between the inner and outer races 1 and 2, and bends 5a and 6b are formed at the ends of the shields 5 and 6 in the same inclination direction with respect to the center line of the bearing. Opposing surfaces 9 and 10 facing each other in parallel with the bent portions 5a and 6b are formed.

When the arc A centering on the center O is drawn in a cross section including the center O of the bearing and parallel to the axis, the facing surfaces 9 and 10 are inclined at the same angle as the tangent line B drawn to the arc A. It has an inclined surface and a labyrinth gap between them.
11 are formed.

The length l ₁ of the labyrinth gap 11 described above is within a range in which the tip of the bent portion 5a or the inner surface of the outer shield plate 6 does not contact the outer surface of the bearing seal 4 when the inner ring 1 and the outer ring 2 are maximally inclined. Set to maximum dimensions. Here, in FIG.
The labyrinth gaps of the embodiment are obtained by taking the amount of displacement at the forming positions of the labyrinth gaps 11 and 22 of the embodiment and the conventional structure shown in FIG. 4 when the inner and outer wheels are inclined.
The distance R ₁ from the bearing center O of 11 is smaller than the distance R ₂ from the bearing center O of the labyrinth gap 22 of the conventional structure (R ₁ <
Due to R ₂ ), the displacement amount with respect to the bearing center O is obviously smaller in the embodiment as shown in the figure. Therefore, it becomes possible to increase the length of the labyrinth gap 11 of the embodiment as compared with the conventional structure by the amount of the decrease in the above displacement,
The labyrinth effect can be improved.

In the above structure, when the axes of the inner ring 1 and the outer ring 2 are inclined, the facing surfaces 9 and 10 having the same inclination with respect to the bearing center O are formed.
Moves on the same locus with respect to the bearing center O, so that the size of the labyrinth gap 11 between them is always kept constant. Therefore, a stable labyrinth effect can be obtained regardless of the amount of inclination of the inner and outer races 1 and 2, and it is possible to reliably prevent the entry of muddy water or the like into the bearing.

In the above embodiment, the facing surfaces 9 and 10 may be formed as curved surfaces that are part of an arc centered on the bearing center O. Even in this case, since the opposing surfaces 9 and 10 move at the same distance with respect to the bearing center O, the same contact state can always be obtained.

FIG. 2 shows an example of a contact type seal structure. In this embodiment, a part of the outer surface of the elastic material of the bearing seal 12 is projected outward to form an annular lip 13. are doing.

The lip 13 is inclined so as to approach the inner ring 1 from the root to the tip 13a, and is continuously formed on the same circumference.

An inner shield plate 14 is attached between the inner and outer races 1 and 2 on the outer side of the bearing seal 12. This inner shield 14
Is a thin metal plate formed in an annular shape, the inner diameter end of which is press-fitted and fixed to the inner ring 1.

The outer diameter end of the inner shield plate 14 is a bent portion 14a that bends in the same direction as the protruding direction of the lip 13, and a sliding contact surface 15 on which the tip of the lip 13 slides on the outer surface of the bent portion 14a.
Are formed.

The sliding contact surface 15 is an inclined surface that is inclined at the same angle as the tangent line B with respect to the arc A centered on the center O in the cross section parallel to the axis including the center O of the bearing.
The contact length l ₃ between the sliding contact surface 15 and the lip 13 is such that the tip of the bent portion 14a and the bearing seal 1 when the inner ring 1 and the outer ring 2 are maximally inclined.
The distance is set to be larger than the distance between the outer surface and the outer surface of the lip 2, and the lip 13 and the sliding contact surface 15 are always in contact with each other. In this case, the lip 13 is pressed against the sliding contact surface 15 by the elastic force of the elastic material 12a.

An annular outer shield 16 is attached to the inner surface of the outer ring 2 so as to face the inner shield 14, and the inner end of the outer shield 16 has a sliding contact surface 15 of the inner shield 14. It has reached the vicinity. A slight gap 17 is provided between the tip of the outer shield plate 16 and the outer end of the sliding contact surface 15 of the inner shield plate 14. Therefore, it is possible to prevent muddy water or rainwater from directly contacting the contact portion between the lip 13 of the bearing seal 12 and the sliding contact surface 15 and to improve the sealing performance.

In the above structure, when the shafts of the inner ring 1 and the outer ring 2 are inclined and the distance between the bearing seal 12 and the inner shield plate 14 changes, the lip 13 slides on the sliding contact surface 15 along the protruding direction. , The tightening margin of the lip 13 is always kept constant. For this reason,
Torque does not increase or heat is generated at the contact portion between the lip 13 and the sliding contact surface 15, and wear of the lip 13 is suppressed to a small level.

Further, since the lip 13 slides on the sliding contact surface 15 that is inclined in the same direction as the protruding direction, almost no compressive stress is applied to the tip of the lip 13. Therefore, the lip 13 has a seventh
The waviness phenomenon as shown in the figure does not occur, and the lip 13 slides with the sliding surface 15 always keeping the same contact state.

Therefore, muddy water, rainwater, or the like that has entered the inside shield plate 14 through the gap between the inside shield plate 14 and the outside shield plate 16 is blocked by the bonding portion between the lip 13 and the sliding contact surface 15, and goes to the inside of the bearing seal 12. Are prevented from entering. The muddy water or the like flows downward along the outer surface of the lip 13 and is discharged from a gap formed between the inner shield plate 14 and the outer shield plate 16 below the bearing.

[Effect of device]

As described above, the first means of the present invention bends the inner shield plate and the outer shield plate in an arc centered on the bearing center or in a tangential direction thereof, and forms a labyrinth gap between the bent portions. Therefore, the labyrinth gap can be always kept constant no matter how the bearing is inclined, and the length of the labyrinth gap can be maximized.

In the second means of this invention, the lip of the bearing seal and its sliding contact surface are along the inclination of the bearing, and the inner shield plate and the outer shield plate are opposed to each other with a slight gap. It is possible to always keep the contact state of the same in the same state and to suppress the direct influence of rainwater or the like on the lip.

Therefore, the present invention realizes the improvement and stabilization of the sealing performance in the seal structure using the labyrinth gap and the seal structure using the contact lip, respectively. It is possible to reliably prevent such intrusion, and to provide stable bearing performance over a long period of time.

[Brief description of drawings]

FIG. 1 (a) is a vertical sectional side view showing an embodiment according to the present invention, FIG. 1 (b) is a diagram showing a main part of the same, and FIG. 2 is a vertical sectional side view showing another embodiment. The figure shows the relationship between the inclination of the bearing and the amount of displacement, FIGS. 4 to 6 are longitudinal side views showing a conventional example, and FIG. 7 is a diagram showing the ripple phenomenon of the lip. 1 ... Inner ring, 1 ... Outer ring, 3 ... Ball rolling surface, 4 ...
Bearing seal, 5 ... Inner shield plate, 6 ... Outer shield plate, 9, 10 ... Opposing surface, 11 ... Labyrinth gap, 12 ...
… Bearing seal, 13 …… Lip, 14 …… Inner shield, 15
…… Sliding surface, 16 …… Outer shield, O …… Bearing center, A
…… Arc, B …… tangent.

Claims (2)

[Scope of utility model registration request] 1. Rolling surfaces of an inner ring and an outer ring are formed with a radius of curvature larger than a radius of a ball incorporated between them, and bearing seals having an outer surface made of an elastic material on both sides of each rolling surface, and a metal. In a self-aligning seal structure of a ball bearing having a tilt function in which a shield plate made of metal is sequentially provided from the inside, the shield plate is formed by an inner shield plate fixed to the inner ring and an outer shield plate fixed to the outer ring. , The free ends of the shield plates are bent so as to face each other with a circular arc centered on the bearing center or with a tangent to the circular arc in a cross section parallel to the axis including the bearing center, A self-aligning seal structure for a ball bearing having a tilt function, characterized in that a labyrinth gap is formed between each bent portion. 2. Rolling surfaces of the inner ring and the outer ring are formed with a radius of curvature larger than the radius of the balls incorporated between them, and bearing seals having an outer surface made of an elastic material on both sides of each rolling surface, and a metal. In a self-aligning seal structure of a ball bearing having a tilt function in which a shield plate made of metal is sequentially provided from the inside, the shield plate is formed by an inner shield plate fixed to the inner ring and an outer shield plate fixed to the outer ring. A lip continuously protruding on the circumference is formed on the outer surface of the bearing seal, and a slide contact surface with which the tip of the lip slides is formed on the free end portion of the inner shield plate. In the cross section parallel to the axis including the bearing center, the contact surface is inclined at an angle of a tangent to an arc centered on the bearing center, and the free end portion of the outer shield plate and the sliding contact surface outer end portion There was a small gap between Self-aligning sealing structure of the ball bearing having a tilt function characterized.