JP2012241824A - Bearing unit with packing seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing unit with a packing seal, which prevents separation between a slinger and a core metal, while preventing damage to an encoder.SOLUTION: A slinger 10 has an overall annular shape having an L-shaped cross section, and comprises a slinger cylindrical portion 13 and a slinger disk portion 12, the slinger cylindrical portion 13 being fixed to an inner race 1. A seal ring 20 comprises an annular seal member 24 made of an elastic material and an annular core metal 21 reinforcing the seal member 24, and is fixed to an outer ring 2. The seal member 24 is made of a rubber molding. Front end edges of two side lips 25, 25 are in elastically sliding contact with the axial outside surface of the slinger disk portion 12. The front end edge of a radial lip 26 is in elastically sliding contact with the outer circumferential surface of the slinger cylindrical portion 13. The axial outer end of the slinger cylindrical portion 13 includes a stepped portion 14 which is formed by folding it inward in the axial direction, the stepped portion facing close to the axial outside surface of the radial lip 26.

Description

  The present invention includes, for example, a plurality of bearing units for rotatably supporting a vehicle wheel with respect to a suspension device, which are disposed between mutually facing peripheral surfaces of a rotation side raceway and a stationary side raceway. The present invention relates to a bearing unit with a pack seal in which an end opening of a bearing internal space in which individual rolling elements are installed is closed by a pack seal composed of a slinger and a seal ring.

  Conventionally, the bearing unit has been provided with various sealing devices to shield the inside of the bearing from the outside and keep it in a sealed state (airtight state and liquid-tight state), and by providing the sealing device, Prevents foreign matter (e.g., muddy water, dust, etc.) from entering the bearing unit from the outside, and prevents lubricant (e.g., grease, lubricating oil, etc.) enclosed inside from leaking to the outside. It is preventing.

As such a sealing device, various elastic materials (for example, rubber, elastomers, plastics, etc.) are formed on a part of an annular cored bar formed by pressing or the like such that a steel plate or the like has an L-shaped cross section. There is a contact type seal having a structure in which molecular materials are connected, and there is a non-contact type shield formed from a metal plate (steel plate) such as a stainless steel plate or an iron plate by press working or the like. Further, the contact type seal (seal ring) and the non-contact type shield (slinger) are combined so that the cross-sectional shape is substantially box-shaped (rectangular), and a contact-type sealing device (so-called pack seal) having a package structure. ) Is also known.
The pack seal not only has the advantage of having a small cross-sectional area and does not require a large installation space, but also has an excellent feature that its sealing performance is very high. It is widely used as a sealing device for bearing units (for example, hub unit bearings for supporting automobile wheels) that require a level of muddy water intrusion prevention effect.

  FIG. 6 shows an example of a conventional structure of a bearing unit for rotatably supporting a vehicle wheel with respect to a suspension device. The bearing unit 51 shown in FIG. 6 includes an outer ring 2 that is a stationary side race ring that is supported and fixed to a suspension device and does not rotate during use, and a hub that is a rotation side race ring that rotates while supporting and fixing the wheel during use. 52 are arranged concentrically with each other. And the double row outer ring raceways 54, 54 each provided on the inner peripheral surface of the outer ring 2 are stationary side tracks, and the double row each provided on the outer peripheral surface of the hub 52 is a rotary side track. Between the inner ring raceways 55 and 55, a plurality of balls 56 and 56, each of which is a rolling element, are arranged in each row. These balls 56 and 56 are held by rolls 57 and 57, respectively, so as to be freely rollable. The hub 52 includes a hub main body 53 and an inner end of the hub main body 53 in the axial direction ("inner" with respect to the axial direction refers to the center in the width direction of the vehicle in the assembled state in the automobile, as shown in FIG. On the other hand, it consists of an inner ring 1 that is externally fitted and fixed to the outside in the width direction of the vehicle. Of the inner ring raceways 55, 55, the inner ring raceway 55 on the outer side in the axial direction is on the outer peripheral surface of the intermediate portion of the hub body 53, and the inner ring raceway 55 on the inner side in the axial direction is on the outer peripheral surface of the inner ring 1. , Each is formed.

Both end openings of an annular bearing inner space 58 in which the balls 56 are installed between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 52 are respectively sealed by a seal ring 59 and a pack seal 60. It is clogged up around the perimeter.
This prevents grease existing in the bearing internal space 58 from leaking into the external space and prevents foreign matter such as moisture and dust existing in the external space from entering the bearing internal space 58. Yes.

  A pack seal 60 as shown in FIG. 6 is composed of a slinger 61 and a cored bar 62 which are arranged to face each other at a predetermined interval, and a seal member 63 interposed therebetween. In this case, both the slinger 61 and the cored bar 62 are formed in an annular shape having a substantially L-shaped cross section, and the seal member 63 is connected to the cored bar 62 to form a seal ring 64, A radial lip that is in sliding contact with the slinger 61 and two side lips are provided.

  By the way, in the sealing device of the pack seal structure, the slinger 61 and the seal ring 64 may be separated at the time of distribution or transportation before being assembled to the bearing unit. When the slinger 61 and the seal ring 64 are separated, it is necessary to reassemble the slinger 61 and the seal ring 64 at the time of assembling the bearing unit, and the assembling work of the sealing device to the bearing unit cannot be performed smoothly. There is a risk of causing a situation. In particular, the double side lip type pack seal configured as shown in FIG. 6 has a low torque and good sealing performance, but due to the reaction force of the two side lips, the slinger 61 and There is a problem that the seal ring 64 is easily separated.

  As a prior art for improving this portion, Patent Document 1 includes a retaining lip portion that extends to a position where the slinger cylindrical portion overlaps the core ring collar portion of the seal ring. A pack seal is disclosed in which the slinger and the seal ring are not separated and separated from each other in the transportation process by sandwiching the cored bar part and the seal lip member.

JP 2010-065737 A

  However, this prior art needs to vulcanize and mold the retaining lip on the slinger, which increases the manufacturing cost. In addition, when the seal ring and the slinger are combined, the grease applied in advance to the side lip on the inner diameter side (the cylindrical portion side of the slinger) is scraped off by the retaining lip. Further, there is a problem that the side lip on the inner diameter side may be reversed by the retaining lip, or the radial lip may fall on the outer side of the core metal (outside the pack seal).

  The present invention includes a pack seal that prevents the slinger and seal ring from separating during distribution and transportation before being assembled to the bearing unit, and that allows the slinger and seal ring to be combined easily and reliably. Another object is to provide a bearing unit with a pack seal.

In order to solve the above problems, a bearing unit with a pack seal according to the present invention includes a bearing unit and a pack seal.
Of these, the bearing unit includes a rotation-side raceway and a stationary-side raceway arranged concentrically with each other, and a rotation-side raceway and a stationary-side provided respectively on the mutually opposing circumferential surfaces of the rotation-side raceway and the stationary-side raceway. A plurality of rolling elements provided so as to be freely rollable between the side track and
The pack seal closes an end opening of an annular space between the circumferential surfaces facing each other of the rotation side raceway and the stationary side raceway, and includes a slinger and a seal ring.
The slinger is made by bending a metal plate, and is formed into an annular shape as a whole, and includes a cylindrical portion and a circular portion bent radially from one axial end edge of the cylindrical portion. Of these, the cylindrical portion is fitted and fixed by being press-fitted into a part of the peripheral surface of one of the rotating side raceway and the stationary side raceway.
The seal ring includes an annular cored bar and an annular seal member made of an elastic material reinforced by the cored bar, and the cored bar is formed by bending a metal plate. It is formed in an annular shape, and includes a cylindrical part and a disk part bent in a radial direction from one axial end edge of the cylindrical part, and the cylindrical part is a peripheral surface of the other race ring The tip of the plurality of seal lips constituting the seal member is in sliding contact with the surface of the slinger over the entire circumference.
Grease is applied to the seal lip, and includes two axial lips that are in sliding contact with the disk portion of the slinger, and a radial lip that is in sliding contact with the cylindrical portion of the slinger, and the axial direction of the cylindrical portion of the slinger A step portion is provided by folding back the end portion, and the radial lip faces the step portion in the axial direction.

  Further, the slinger may be provided with an annular encoder as a detected body of a sensor for measuring the rotation state of the bearing on the disk portion of the slinger.

  According to the bearing unit with a pack seal of the present invention, the folding step provided on the cylindrical portion of the slinger and the radial lip face each other in the axial direction. And the seal ring can be prevented from separating, and the slinger and the seal ring can be easily and reliably combined. As a result, there is an effect that the pack seal can be smoothly assembled to the bearing unit.

Sectional drawing which shows the structure of the bearing unit with a pack seal which concerns on 1st Embodiment of this invention. The enlarged view of the folding | turning part in FIG. Sectional drawing which shows the structure of the bearing unit with a pack seal which concerns on 2nd Embodiment of this invention. Explanatory drawing which shows the state which piled up the bearing unit with a pack seal which concerns on 2nd Embodiment. Explanatory drawing which shows the state which accumulated the bearing unit with a pack seal which concerns on the modification of 2nd Embodiment. Sectional drawing which shows the structural example of the conventional bearing unit with a pack seal.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention. The feature of this example is that the structure of the pack seal is devised, and the structure and operation of other parts are the same as those of the conventional structure shown in FIG. Is omitted or simplified, and the following description will focus on the features of this example.

  The axially inner end opening of the bearing internal space 58 (see FIG. 6) is closed over the entire circumference by the pack seal 3 fitted between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the inner ring 1. Yes. In the case of this example, the pack seal 3 includes a slinger 10 and a seal ring 20, and is configured as a structure (so-called package structure) in which the slinger 10 and the seal ring 20 are combined so that the contour shape of the cross section becomes a substantially rectangular shape. Has been.

Of these, the slinger 10 is formed by punching or bending a rust-free steel plate such as stainless steel by press forming such as burring, so that the entire slinger 10 has an L-shaped cross section and is formed into an annular shape. It consists of a slinger disc portion 12 that is bent radially outward from the axial inner end edge of the slinger cylindrical portion 13. Such a slinger 10 is fixed to the inner ring 1 by fitting the slinger cylindrical portion 13 to the outer peripheral surface of the inner end portion in the axial direction of the inner ring 1 by interference fitting (press-fit outer fitting).
The seal ring 20 includes an annular seal member 24 made of an elastic material, and an annular cored bar 21 that reinforces the seal member 24. The cored bar 21 is formed by punching or bending a metal plate by press forming and is formed into an annular shape as a whole with an L-shaped cross section. The cored bar cylindrical portion 23 and the axially outer side of the cored bar cylindrical portion 23 are formed. It consists of a cored bar part 22 bent radially inward from the end edge. The width of the pack seal 3 is reduced by bending the core bar 21 into an L-shaped cross section. Such a seal ring 20 is fixed to the outer ring 2 by fitting the cored bar cylindrical part 23 into the inner circumferential surface of the inner end part in the axial direction of the outer ring 2 by an interference fit (press fit). . Further, in this state, the tip edges of the plurality of seal lips constituting the seal member 24 are brought into sliding contact with the surface of the slinger 10 over the entire circumference.

The seal member 24 is formed of a molded body of an elastic body (for example, rubber) and is integrally fixed to the core metal cylindrical portion 23 and the core metal disc portion 22 of the core metal 20. As shown in FIG. 1, the two side lips 25, 25 are elastically slidably contacted with the axially outer side surface of the slinger disc portion 12 with the tip edge being the base metal disc portion 22 as a base, and the radial lip 26 is The tip edge is elastically slidably contacted with the outer peripheral surface of the slinger cylindrical part 13 with the cored bar part 22 as a base. Further, grease 27 is applied in the vicinity of the front edge of the side lips 25, 25, and is in sliding contact with the slinger disc portion 12 with the grease 27 applied.
An outer end portion in the axial direction of the slinger cylindrical portion 13 in the slinger 10 is folded back inward in the axial direction to form a step portion 14, and the step portion 14 is formed in a state where the slinger 10 is a single body. Further, the folding step portion 14 is positioned on the outer side in the axial direction with respect to the radial lip 26, and is in close proximity to the outer surface in the axial direction of the radial lip 26.
The step portion 14 protrudes radially outward from the slinger cylindrical portion 13 and faces the radial lip 26 in the axial direction, thereby preventing the slinger 10 and the seal ring 20 from being separated. Further, since the slinger 10 is formed with the slinger 10 as a single unit, the step 14 can be easily processed and the step 14 can be formed while suppressing deformation of the inner diameter surface of the slinger cylindrical portion 13.

  Next, the configuration of the radial lip 26 and the stepped portion 14 will be described in detail with reference to FIG. The base inner diameter dimension of the axial lip 25 located on the inner diameter side is set to be larger than the outer diameter dimension of the folding step section 14 and larger than the inner diameter dimension of the cored bar part 22. Accordingly, when the pack seal is assembled, the axial lip 25 is prevented from falling to the inner diameter side when the inner diameter side axial lip 25 passes through the folded step portion 14, and the grease 27 applied to the axial lip 25 is stepped. It is possible to prevent the portion 14 from being scraped off. Specifically, assuming that the outer diameter dimension of the folded step portion 14 is D1, the inner diameter dimension of the cored bar portion 22 is D2, and the base inner diameter dimension of the axial lip 25 located on the inner diameter side is D3, D1 <D2 <D3. And Further, if the distance between the inner diameter of the base of the radial lip 26 and the outer diameter of the folded step 14 is H, and the thickness of the radial lip 26 is T, the distance is set within the range of 2 × T ≦ H ≦ 3 × T. To do. If the distance H is less than twice the thickness of the radial lip 26, the radial lip 26 may be in a solid contact state with the step 14 when the pack is assembled, when the radial lip 26 passes through the folded step 14. . On the other hand, when the distance H is greater than three times the thickness of the radial lip 26, the rigidity of the radial lip 26 is reduced, and the effect of non-separation between the slinger 10 and the seal ring 20 is lost.

With the above configuration, it is possible to prevent the slinger and the seal ring from being separated during distribution or transportation before the pack seal is assembled to the bearing unit. Furthermore, when the slinger and the seal ring are assembled, the seal lip can be easily and surely combined without being inverted or the grease applied to the seal lip being scraped off. As a result, the pack seal can be smoothly assembled to the bearing unit without impairing the seal performance of the pack seal.
Further, a labyrinth seal is formed between the stepped portion and the radial lip, and grease leakage from the bearing internal space can be prevented. Further, since the folding step portion of the slinger cylindrical portion has high radial rigidity, the fitting force and the sealing performance between the slinger and the bearing fitting surface can be improved.

[Second Example of Embodiment]
FIG. 3 shows a second example of the embodiment of the present invention, which is an example of a pack seal with an encoder. In the case of the pack seal 3a of this example, the slinger 10a is formed by molding a rust-free magnetic steel plate, and is formed on the inner surface in the axial direction of the slinger disc portion 12 in a ring shape for constituting a rotational speed detection device. The multipolar magnet encoder 30 is fixedly attached. A magnetic sensor (not shown) is installed opposite to the encoder 30, and the rotational speed and rotation angle of the bearing can be detected by this sensor and the encoder 30 (sensor detected body). Furthermore, the chamfered portion 14 is provided with a chamfered portion 15 whose outer diameter decreases toward the radial lip 26, and the inner end surface in the axial direction of the stepped portion 14 has a smooth surface without burrs or the like. When the pack seal is combined, the chamfered portion 15 can be assembled so that the radial lip has a predetermined position and shape. Even when the radial lip 26 and the stepped portion 14 are in contact with each other during the rotation of the bearing, the radial inner lip 26 of the stepped portion 14 has a smooth surface free from burrs and the like, so that the radial lip 26 is not damaged.

Normally, as shown in FIG. 4, the pack seal 3a is packaged in a rod shape in a state of being stacked in the axial direction and shipped from a seal factory. In the bearing factory, the pack seal 3a is applied to the distribution device in the form of a rod, and is sequentially cut out by a dharma dropping method and then press-fitted into the bearing unit.
In the pack seal 3a with an encoder stacked in the axial direction, the encoder 30 of one adjacent pack seal 3a and the outer surface in the axial direction of the other pack seal 3a rub against each other, and the surface of the encoder 30 may be damaged. . Further, when the slinger 10 also serves as the back yoke of the encoder 30, one encoder 30 adsorbs the axially outer surface of the other adjacent slinger 10 and becomes more easily scratched, and the seal ring 20 and the slinger 10 are separated. It tends to occur.

In the pack seal 3a having the folded-back step portion 14 of the present embodiment, it is possible to suppress the occurrence of the above-described problems during conveyance. As shown in FIG. 4, the folding stage 14 part of the slinger 10 is partially inserted into the inner diameter of the other encoder 30 adjacent to the slinger 10 so as to be in contact with the slinger 10. With such a configuration, since the encoder 30 does not come into contact with the adjacent pack seal, it is possible to prevent scratches. In addition, since a sufficient gap is maintained between the encoder 30 and the adjacent pack seal, the magnetic force between the encoder 30 and the adjacent pack seal is weakened by the gap, and scratches and the seal ring 20 and the slinger 10 Separation can be suppressed. Furthermore, since the folding step portion 14 is easily kept in a rod winding state by the magnetic force of the encoder 30, it can be easily put into a packaging or a distribution device. In the case of the present embodiment, the pack seal distributing device may be a method of inserting and cutting out the claw for the distribution into the outer diameter side gap between the pack seals.

  The pack seal 3b in FIG. 5 is a modification of the present embodiment, and the folding step portion 14 of the slinger 10 is brought into contact with the surface of the adjacent encoder 30a by reducing the inner diameter side of the encoder 30a. The outer end portion in the axial direction of the folded step portion 14 that comes into contact with the encoder 30a has a curved surface that is smooth by bending. Hateful. Further, since the folded step portion 14 has a cylindrical shape, the end portion of the cylinder is in contact with the encoder 30a, and the cylindrical surface portion is not opposed to the encoder 30a, the adsorption force of the step portion 14 due to the magnetic force of the encoder 30a is minimized. Therefore, the generation of scratches can be suppressed.

  In each of the above embodiments, the inner ring 1 is a rotation side member and the outer ring 2 is a fixed side member. However, the present invention can be applied to the case where the inner ring 1 is a fixed side member and the outer ring 2 is a rotation side member. is there. In this case, the slinger cylindrical portion 13 is fitted to the inner diameter surface of the outer ring 2, the slinger disc portion 12 is formed inward, and the core metal cylindrical portion 23 is fitted to the outer diameter surface of the inner ring 1. At the same time, the cored bar part 22 is formed outward. Moreover, although the example applied to the bearing unit which supports the wheel of a motor vehicle was described, the pack seal | sticker of this invention is applicable also to the bearing unit of another rotation part.

  The bearing unit with a pack seal of the present invention can be applied to rotation support of a wheel.

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3, 3a, 3b Pack seal 10, 10a Slinger 12 Slinger disc part 13 Slinger cylindrical part 14 Step part 15 Chamfer part 20 Seal ring 21 Core metal 22 Core metal disk part 23 Core metal cylindrical part 24 Seal member 25 Side lip 26 Radial lip 27 Grease 30, 30a Encoder 51 Bearing unit 52 Hub 53 Hub body 54 Outer ring raceway 55 Inner ring raceway 56 Ball 57 Cage 58 Bearing inner space 59 Seal ring 60 Pack seal 61 Slinger 62 Core metal 63 Seal member 64 Seal ring

Claims (2)

A bearing unit and a pack seal;
Of these, the bearing unit includes a rotation-side raceway and a stationary-side raceway arranged concentrically with each other, and a rotation-side raceway and a stationary-side provided respectively on the mutually opposing circumferential surfaces of the rotation-side raceway and the stationary-side raceway. A plurality of rolling elements provided so as to be freely rollable between the side track and
The pack seal closes an end opening of an annular space existing between the mutually facing peripheral surfaces of the rotating side raceway and the stationary side raceway, and includes a slinger and a seal ring.
The slinger is made by bending a metal plate, and is formed into an annular shape as a whole, and includes a cylindrical portion and a circular portion bent radially from one axial end edge of the cylindrical portion. The cylindrical portion of these is fitted and fixed by press-fitting into a part of the circumferential surface of one of the rotating side raceway and the stationary side raceway,
The seal ring includes an annular cored bar and an annular sealing member made of an elastic material reinforced by the cored bar, and the cored bar is annularly formed by bending a metal plate. A cylindrical portion and a disc portion bent radially from one axial end edge of the cylindrical portion, and the cylindrical portion of the cylindrical portion is a part of the circumferential surface of the other race ring. A bearing with a pack seal, which is fitted and fixed to a portion facing the slinger at the portion, and the tip ends of a plurality of seal lips constituting the seal member are slidably contacted with the surface of the slinger over the entire circumference. In the unit,
Grease is applied to the seal lip, and includes two axial lips that are in sliding contact with the disk portion of the slinger, and a radial lip that is in sliding contact with the cylindrical portion of the slinger, and the axial direction of the cylindrical portion of the slinger A bearing unit with a pack seal, wherein a step portion is provided by folding back an end portion, and the radial lip is opposed to the step portion in the axial direction.   The bearing unit with a pack seal according to claim 1, wherein the slinger is provided with an annular encoder as a detected body of a sensor for measuring a rotation state of the bearing on a disk portion of the slinger. .

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