CN203189536U - Rolling beating unit for supporting wheel - Google Patents

Abstract

The utility model provides a rolling bearing unit for supporting wheels. The bearing unit has excellent durability and can significantly improve the ability to prevent foreign matter from entering the inner space of the bearing without increasing the rotation resistance. The labyrinth sealing lip (33) is located on the radially outer side of the main sealing lip (32a) closest to the external space, and at the same time is located on the forged surface of the rotating side flange (12) formed by cold rolling to one end and the grinding process. Radially outside of the step (20) between the sliding surfaces (21). The top of the labyrinth sealing lip (33) overlaps with the step (20) in the radial direction and is opposed to and affixed in the entire circumferential direction, so that between the inner peripheral surface of the top end of the labyrinth sealing lip (33) and the outer peripheral surface of the step (20) Form an axial labyrinth seal.

Description

Rolling bearing units for supporting wheels

technical field

The utility model relates to a rolling bearing unit for supporting automobile wheels. The rolling bearing unit supports the wheel of the vehicle to rotate freely relative to the suspension, and seals the end opening of the internal space of the bearing with a sealing ring or a combined sealing component.

Background technique

For the rolling bearing unit used to support the rotation of the automobile wheel relative to the suspension, Patent Document 1 provides the following structure: a sealing ring is provided at one end of the inner space of the bearing with rolling elements, and a combined sealing member is provided at the other end.

In order to ensure the durability of the rolling bearing unit, it is very important to improve the sealing performance of these sealing devices, prevent foreign substances from entering the bearing inner space, and at the same time try to prevent the grease filled in the bearing inner space from leaking out. On the other hand, these seals work in harsh environments with splashes of mud and water. Especially for the sealing ring, foreign substances such as muddy water move radially inward along the inner surface of the flange and enter between the main sealing lip of the sealing ring and the sliding surface of the inner surface of the flange, which may cause abnormal wear on the sliding surface and other damage. In addition, the moisture in the muddy water entering the sealed space will solidify after evaporation. Once the solid mud accumulated in the sealed space adheres to the main sealing lip, it may hinder the normal movement of the main sealing lip, and make a part of the top edge of the main sealing lip slip from The face is raised. As a result, external muddy water and other substances may enter the inner space of the bearing through the tilted part.

In order to improve the sealing performance of the combined sealing part, Patent Document 2 provides the following structure: a second sealing ring is embedded on the outer ring, and the top edge of the sealing lip of the second sealing ring is connected to the outer side of the disk part of the retaining ring (with the main sealing ring Opposite retaining ring side) the entire circumferential sliding contact. This structure can prevent foreign matter from entering the inner space of the bearing, but increases the cost due to the increased number of parts. In addition, installing the second seal ring requires space, and in order to prevent interference with other parts provided adjacent to the bearing unit, the degree of freedom in design may be limited. Furthermore, the sealing lip of the second sealing ring is added on the basis of the original sealing lip of the composite sealing part, and the added sliding contact pair will increase the rotational resistance (dynamic friction moment) of the rolling bearing unit.

patent documents

Patent Document 1 Japanese Unexamined Patent Publication No. 2007-085478

Patent Document 2 Japanese Unexamined Patent Application Publication No. 2008-151311

Utility model content

Problems to be solved by utility models

In view of the above problems, the purpose of this utility model is to provide a rolling bearing unit for supporting a wheel. The rolling bearing unit has excellent durability, and a sealing device with good sealing performance is provided at the end opening of the inner space between the ring on the stationary side and the ring on the rotating side. Significantly improve the ability to prevent foreign matter from entering the inner space of the bearing under the premise.

means of solving problems

The rolling bearing unit used to support the wheel involved in the utility model has:

an outer ring having an outer ring raceway on its inner peripheral surface;

an inner ring arranged coaxially with the outer ring, and has an inner ring raceway on its outer peripheral surface opposite to the outer ring raceway;

A plurality of rolling elements are free to roll between the raceway of the outer ring and the raceway of the inner ring.

a flange integral with the inner ring and extending radially outward from the outer peripheral surface of the inner ring by forging;

The sealing ring seals the end opening of the internal space between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring.

A sliding surface formed after grinding is provided on the outer peripheral surface of the inner ring; the sealing ring is composed of a skeleton and an elastic sealing material body, the skeleton is fixed at the end of the outer ring, and the elastic sealing material body adhere to the backbone;

The elastic sealing material body has at least one main sealing lip that contacts and slides in the circumferential direction with the sliding surface, and a labyrinth sealing lip is provided radially outside the main sealing lip, and the top end of the labyrinth sealing lip is in contact with the sliding surface. The side faces of the flange are opposite and close to each other in the circumferential direction, so as to form a labyrinth seal with the side faces of the flange.

In particular: in the rolling bearing unit for supporting wheels provided by the utility model, the side of the main part of the flange has a forged surface formed by cold rolling, and there is a step between the forged surface and the sliding surface , the top end of the labyrinth sealing lip is located radially outside the step and radially overlaps with the step.

The effect of utility model

According to the rolling bearing unit for supporting the wheel provided by the utility model, it can significantly improve the sealing performance of each sealing device, prevent foreign matter from entering the inner space of the bearing without increasing the rotation resistance, and realize the excellent durability of the rolling bearing unit.

In particular, the labyrinth sealing lip of the utility model extends further to the flange side beyond the sliding contact point of the main sealing lip of the sealing ring. Improve the labyrinth sealing effect. In addition, the flange side on the radially outer side of the step is a forged surface with radial rolling marks formed by cold rolling. Therefore, the centrifugal force when the flange rotates can make it easier to throw out the muddy water etc. on the flange in the radial direction. Therefore, foreign matter such as muddy water can be prevented from reaching the main sealing lip to the greatest extent, preventing abnormal wear of the sliding contact part of the main sealing lip, and at the same time preventing a large amount of solid mud from adhering to the main sealing lip and hindering the normal movement of the main sealing lip. Therefore, the sealing performance can be exhibited well for a long period of time, and the durability of the rolling bearing unit can be ensured. Moreover, since the labyrinth seal lip system is non-contact, the rotational resistance (dynamic friction moment) of the rolling bearing unit is not increased.

Description of drawings

Fig. 1 is a cross-sectional view of a rolling bearing unit according to the first embodiment of the present invention.

Fig. 2(a) is a side view of the inner ring in Fig. 1 .

Fig. 2(b) is a cross-sectional view along A-A direction in Fig. 2(a).

Fig. 2(c) is a side view of the outer ring in Fig. 1 .

Fig. 2(d) is a cross-sectional view along B-B direction in Fig. 2(c).

Fig. 3 is a cross-sectional view of the sealing ring in Fig. 1 .

Fig. 4 is a cross-sectional view of a modified example of the sealing ring in Fig. 1

Fig. 5 is a cross-sectional view of a rolling bearing unit according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of the sealing ring in FIG. 5 .

Fig. 7 is a cross-sectional view of the combined sealing member in Fig. 5 .

Fig. 8 is a cross-sectional view of a rolling bearing unit according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional view of the sealing ring in FIG. 8 .

Fig. 10 is a cross-sectional view of the combined sealing member in Fig. 8 .

Explanation of reference signs

1, 1a, 1b Rolling bearing units for supporting wheels

2, 2a, 2b outer ring

3, 3a, 3b inner ring

4, 4a, 4b, 4c, 4d rolling elements

5, 5a Stationary side flange

6, 6a, 6b, 6c, 6d outer ring raceway

7, 7a, 7b inner ring body

8 inner ring components

9 riveting part

10, 10a, 10b, 10c, 10d inner ring raceway

11 cage

12, 12a swivel side flange

13 bolts

14, 14a～14c sealing ring

15 interior space

16 lids

17, 17a encoder

18 sensors

19, 19a combined sealing parts

20 steps

21 sliding surface

22 annular groove

23 Guidance Department

24, 24a mounting holes

25 small path steps department

26 spline holes

27 constant velocity joint parts

28 spline shaft

29 nuts

30, 30a, 30b skeleton

31, 31a, 31b sealing material body

32a, 32b main sealing lip

33, 33a labyrinth sealing lip

34 cylindrical fitting part

35, 35a disc part

36 back and forth bending part

37 cylindrical part

38 brim

39 ribs

40, 40a retaining ring

41, 41a sealing ring

42 Cylindrical part of retaining ring

43, 43a retaining ring disc part

44 brim

45, 45a skeleton

46, 46a sealing material body

47a, 47b, 47c main sealing lip

48 sealing ring cylindrical part

49 sealing ring disc part

50 Fitting disc part

51 labyrinth sealing lip

52 labyrinth seal

53 thick wall part

54 steps

55 outer diameter side surface

56 Auxiliary sealing lip

57 inner diameter side surface

58 outside space

59 ribs

Detailed ways

1 to 3 show the first specific embodiment provided by the utility model. The rolling bearing unit 1 for supporting a wheel provided in this embodiment is an inner ring rotation type rolling bearing unit for a driven wheel. Its structure is:

The outer ring 2 is stationary, and has a rotating inner ring 3 inside the outer ring 2 . A plurality of rolling elements 4 installed between the outer ring 2 and the inner ring 3 can roll freely. A stationary side flange 5 is provided on the outer peripheral surface of the outer ring 2, and the stationary side flange 5 is supported and fixed to a suspension device (not shown in the figure). The inner peripheral surface of the outer ring 2 is provided with a double-row outer ring raceway 6 .

In addition, the inner ring 3 is composed of an inner ring body 7 and an inner ring element 8 . The inner ring element 8 is fixed to the inner ring main body 7 through the riveting portion 9 . A double-row inner ring raceway 10 is provided on the outer peripheral surface of the inner ring 3 . Described rolling element 4 has two rows, and each row has a plurality of rolling elements. The two rows of rolling bodies are respectively located between the inner ring raceways 10, 10 and the outer ring raceways 6, 6, and are held by the cages 11, 11 to roll freely.

A rotating side flange 12 is provided near the outer end of the inner ring main body 7 in the axial direction, which protrudes radially outward from the vicinity of the opening of the outer axial end of the outer ring 2 and is equipped with a plurality of bolts 13 . Bolts 13 fix a wheel hub and a brake disc constituting a brake device to the rotating side flange 12 .

In addition, the axially outer side refers to the outer side in the vehicle width direction after the rolling bearing unit is incorporated into the wheel, that is, the left side in each figure except for Fig. 2(a) and (c). The axially inner side refers to the inner side in the vehicle width direction after the rolling bearing unit is installed in the wheel, that is, the right side in each figure except Figure 2 (a) and (c).

In addition, in the illustrated embodiment, balls are used as the rolling elements. If the rolling bearing unit is used in heavy vehicles, tapered rollers are sometimes used as rolling elements.

A sealing ring 14 is installed between the inner peripheral surface of the axially outer end of the outer ring 2 and the outer peripheral surface of the inner ring 3 in the axial middle. An inner space 15 is formed between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the inner ring 3 , a plurality of rolling elements are located in the inner space 15 , and the sealing ring 14 seals the axial outer opening of the inner space 15 . Furthermore, the axially inner opening of the outer ring 2 is closed with a cover 16 . Accordingly, foreign matter such as dust and muddy water in the external space can be prevented from entering the internal space 15 . At the same time, it is possible to prevent the grease filled in the internal space 15 from leaking to the external space.

As shown in Figure 2(a) and (b), the inner ring body 7 is provided with a rotating side flange 12 on the axially outer peripheral surface of the main body 7, which extends radially outward and is aligned with the central axis of rotation. Vertically, a plurality of mounting holes 24 for fixing the bolts 13 are provided at substantially equal intervals in the circumferential direction. At the position of the pitch circle of the installation hole 24 , the rotating side flange 12 is not integrally connected in the circumferential direction. In addition, a guide portion 23 for wheel positioning is provided on the outermost side in the axial direction of the rotation side flange 12 .

The rotating side flange 12 provided on the inner ring main body 7 extends radially outward in a direction perpendicular to the central axis of rotation, is formed by cold rolling to one side and is integrated with the inner ring main body 7 . In addition, during the cold rolling process, the remaining part after pressing to one side forms the guide part 23 , and the guide part 23 is integrated and coaxial with the inner ring main body 7 .

A small-diameter stepped portion 25 is provided on the axially inner side of the inner ring main body 7 (the right side in FIG. 2( b ), and the inner ring element 8 is externally fitted and fixed to the small-diameter stepped portion 25 . The inner ring raceway 10 inside the bearing is provided on the outer peripheral surface of the inner ring element 8 , and the inner ring raceway 10 outside the bearing is arranged on the outer peripheral surface of the axial middle part of the inner ring main body 7 . The axial inner end of the inner ring main body 7 is cylindrical, and the cylindrical end (the riveting part 9 ) is expanded radially outward, and the inner ring element 8 is riveted and fixed to the inner ring main body 7 superior. In addition, besides being fixed by riveting, the inner ring element 8 may also be fixed on the axial inner side of the inner ring main body 7 by using a nut (not shown in the figure).

On the other hand, as shown in Figure 2 (c), (d), the outer ring 2 is hollow cylindrical, and the inner peripheral surface of the outer ring 2 is provided with an inner ring raceway 10 on the outer peripheral surface of the inner ring 3. , 10 correspond to the double row outer ring raceways 6,6. The stationary side flange 5 is arranged on the outer peripheral surface of the axially middle part of the outer ring 2 , which is perpendicular to the central axis and radially extends radially outward. The stationary side flange 5 is provided with a plurality of mounting holes 24a for fixing the outer ring 2 to the suspension. At the pitch circle position of the mounting hole 24a, the stationary side flange 5 is not integrally connected in the circumferential direction. Furthermore, the inner diameter of the axial inner side of the static side flange 5 (the right side of Fig. 2(d)) is a cylindrical hole, and the cover 16 is embedded and fixed in the cylindrical hole; A steering knuckle (not shown in the figure) constituting the suspension device is sleeved on the outer diameter surface of the axial inner side (the right side of Figure 2(d)), and the inner diameter of the steering knuckle faces the outer ring 2 for radial positioning .

The static side flange 5 of the outer ring 2 that is perpendicular to the central axis and radially extends radially outward is formed by cold rolling to one side and is integrated with the outer ring 2 .

In addition, the rolling bearing unit 1 is provided with a rotation speed detection device for detecting the rotation speed of the inner ring 3 (because the inner ring 3 is fixed with the wheel, the actual detection is the rotation speed of the wheel). The rotational speed detection device is composed of an encoder 17 and a sensor 18 opposite to and adjacent to the encoder 17 . The encoder 17 is fixed to the outer peripheral surface of the axially inner end portion of the inner ring element 8 and is coaxial with the inner ring 3 . The encoder 17 is a ring-shaped permanent magnet made of magnetic material, which is magnetized in its axial direction and N poles and S poles are arranged alternately at equal intervals in the circumferential direction of the tested surface. The sensor 18 detects the rotational speed of the inner ring 3 (wheel) by detecting a change in magnetic flux that occurs when the encoder 17 rotates.

As shown in FIG. 3 , the sealing ring 14 provided for sealing the axially outer end opening of the inner space 15 is composed of a skeleton 30 and a sealing material body 31 . The skeleton 30 is made of a metal plate such as a mild steel plate, and has a substantially circular shape with a sealing material body 31 adhered on its surface. Its outer diameter edge is embedded and fixed in an annular groove 22 on the inner peripheral surface of the axially outer end of the outer ring 2 .

The sealing material body 31 is made of elastic material such as rubber and is bonded and fixed with the framework 30 . It has two contacting main sealing lips 32a and 32b, and a labyrinth sealing lip 33 in the shape of a visor. The top edges of the main sealing lips 32a and 32b are respectively in sliding contact with the sliding surface 21 on the outer peripheral surface of the axially middle portion of the inner ring 3 over the entire circumference. In order to ensure the sealing performance of the main sealing lips 32a and 32b, the sliding surface 21 is ground together with the inner ring raceway 10 after heat treatment to form a smooth surface with no grinding traces in the radial or axial direction to ensure the main sealing The sealing properties of the lips 32a, 32b.

The main sealing lip 32a is arranged at the position closest to the external space, and the labyrinth sealing lip 33 is arranged on the radially outer side of the main sealing lip 32a, and its installation position is limited by the step on the inner surface of the main part of the rotating side flange 12 20. The cold-rolled surface (with rolling marks in the radial direction) and the sliding surface 21 (the main sealing lips 32a, 32b and the sliding surface) formed by grinding the flange 12 on the rotating side are formed by cold rolling to one side. 21 contact slide) is the step 20 at the junction.

The labyrinth sealing lip 33 is located radially outside of the step 20 . At the same time, the top end of the labyrinth sealing lip 33 radially overlaps the step 20 , that is, the top end of the labyrinth sealing lip 33 is located axially outside the step 20 . Furthermore, the tip inner peripheral surface of the labyrinth lip 33 and the outer peripheral surface of the step 20 are opposed to and adhered to in the entire circumferential direction. Accordingly, a labyrinth seal is formed in the axial direction between the inner peripheral surface of the top end of the labyrinth lip 33 and the outer peripheral surface of the step 20 . Also, the labyrinth seal lip 33 is inclined radially outward toward the axially outer side.

As described above, the labyrinth seal lip 33 of the rolling bearing unit 1 provided by this embodiment can effectively prevent foreign matter from entering its inner diameter side. Furthermore, even if foreign matter enters the radially inner side and adheres to the inner surface of the rotating side flange 12, the foreign matter can be easily discharged.

That is to say, because the labyrinth seal lip 33 is inclined radially outward toward the axially outer side, muddy water etc., after moving through the outer peripheral surface of the outer ring 2 to the outer peripheral surface of the labyrinth seal lip 33 , is guided to the labyrinth seal lip 33, and then flow to the ground below the bearing, thereby preventing foreign matters such as muddy water from entering the inner diameter side of the labyrinth sealing lip 33. Furthermore, even if foreign matter such as muddy water enters the inner diameter side of the labyrinth sealing lip 33, because the closer the labyrinth sealing lip 33 is to its top end, the inner diameter becomes larger. Then, under the action of the centrifugal force of the rotating side flange 12 , the foreign matter can be effectively discharged to the outer space along the inner peripheral surface of the labyrinth seal lip 33 .

Furthermore, when the workpiece is cold rolled, the friction between the workpiece and the mold causes radial rolling marks on the flange surface. Therefore, grinding is performed on the sliding surface 21 that is in sliding contact with the main seal lip. In addition, compared with hot forging, cold rolling is difficult for material to flow, and the axial inner side of the main body of the flange will form a larger corner. Therefore, there is a large space between the opening that needs to be sealed at the axially outer end of the internal space 15 and the rotating side flange 12, and foreign matter such as muddy water can easily enter. In the seal ring 14 of this embodiment, the visor-shaped labyrinth seal lip 33 completely covers the polished sliding surface 21 in the circumferential direction. Furthermore, since the top end of the labyrinth lip 33 is opposed to the step 20 , foreign matter such as muddy water can be prevented from entering the sliding surface 21 . In addition, the sliding surface 21 on the inner diameter side of the labyrinth sealing lip 33 is a polished smooth surface without rolling marks, which can prevent the occurrence of swirling airflow. On the other hand, the outer side of the step 20 of the rotating side flange 12 has radial rolling marks, and the muddy water entering the sliding surface 21 is thrown outward in the radial direction under the centrifugal force of the rotating side flange 12, and the radial rolling marks lift The throw-out effect. In addition, phosphating treatment is carried out on the workpiece during cold rolling, and the phosphating film on the cold rolling surface can prevent corrosion. In addition, the top end of the labyrinth sealing lip 33 faces the cold rolling surface, and this structure prevents the ground sliding surface 21 from being exposed to the external space at all, thereby achieving good antirust performance.

In addition, the outer ring 2 and the inner ring main body 7 formed by cold rolling have good dimensional accuracy and good surface, which can save subsequent machining and reduce costs. Furthermore, during the cold rolling process, the static side flange 5 and the rotating side flange 12 are formed by extruding to one side, and the strength of the flange is improved by work hardening. Therefore, the weight of the outer ring 2 and the inner ring main body 7 can be reduced while ensuring strength.

Fig. 4 is a modified example of the first embodiment. The frame 30a constituting the seal ring 14a of this modified example is made of a metal plate such as a mild steel plate in an L-shape, and is formed by a cylindrical fitting portion 34 and being bent radially inward from the axially outer end edge of the cylindrical fitting portion 34. The disk part 35 is composed of. The cylindrical fitting portion 34 is fitted in the inner peripheral surface of the axially outer end of the outer ring 2 with an interference fit. In this structure, the annular groove 22 does not need to be processed on the inner peripheral surface of the outer ring 2 .

[Second Specific Implementation Mode]

Fig. 5 and Fig. 6 show the second specific embodiment. The rolling bearing unit 1a provided in this embodiment rotates with an outer ring and is used for a driven wheel. Outer ring raceways 6a, 6b are provided on the inner peripheral surface of the rotating outer ring 2a; inner ring raceways 10a, 10b are provided on the outer peripheral surface of the stationary inner ring 3a. Two rows of rolling bodies 4a, 4b are provided between the outer ring raceways 6a, 6b and the inner ring raceways 10a, 10b, and each row has a plurality of rolling bodies. In addition, the present embodiment employs balls as the rolling elements.

A rotation side flange 12a extending radially outward is provided on the axially outer outer peripheral surface (left side in FIG. 5 ) of the outer ring 2a. A plurality of bolts 13 are arranged at approximately equal intervals in the circumferential direction of the rotating side flange 12a, and the bolts 13 install the wheel hub and the brake disc (not shown in the figure) on the axially outer surface of the rotating side flange 12a.

An inner ring main body 7a is provided on the outer peripheral surface of the axial middle part of the inner ring 3a, and an inner ring raceway 10b (the inner raceway of the bearing) is provided on the inner ring main body 7a, and the inner ring main body 7a is axially inner on the outer peripheral surface of the inner ring main body 7a. The end portion (the right end portion in FIG. 5 ) is provided with a stationary side flange 5a extending radially outward. In addition, a small-diameter step portion 25 is provided at an axially outer end portion of the outer peripheral surface of the inner ring main body 7 a. The inner ring element 8 is sheathed on the small-diameter stepped portion 25 . The inner ring raceway 10a (the raceway on the outer side of the bearing) is provided on the outer peripheral surface of the inner ring element 8 . The inner ring element 8 is fastened to the inner ring body 7 a by caulking the inner ring element 8 with the axially outer end portion (the caulking portion 9 ) of the inner ring body 7 a.

In this embodiment, the diameter of the inner outer ring raceway 6b of the outer ring 2a is larger than the diameter of the outer outer ring raceway 6a, and the diameter of the inner ring raceway 10b (inner raceway) of the inner ring 3a is larger than that of the inner ring raceway 10a. The (outer raceway) has a larger diameter, and the pitch circle diameter (PCD) of the inner row of balls 4b is larger than that of the outer row of balls 4a. Moreover, a pre-tightening force is applied to the two rows of balls 4a and 4b, so that each row of balls forms a contact angle with the inner and outer rings respectively and forms a back-to-back combination. In addition, the inner row of balls 4b has more balls than the outer row of balls 4a.

Furthermore, in this embodiment, the diameters of the balls in the two rows are the same. But the inner row of balls 4b can also adopt balls with a diameter smaller than the outer row of balls 4a.

The raw material of the outer ring 2a is made of spheroidized carbon structural steel to form an annular blank, which is cold rolled and forged to form an outer peripheral surface and an inner peripheral surface, and then extruded to one side to form the rotating side flange 12a . In addition, as shown in FIG. 2( a ), the rotating side flange 12 a is composed of a plurality of flanges in the circumferential direction of the outer ring 2 a, forming a so-called star flange. Furthermore, the axially outer surface of the rotating side flange 12a and the outer peripheral surface of the guide portion 23 can obtain better dimensional accuracy after cold rolling, and no further machining is required.

The raw material of the inner ring body 7a constituting the inner ring 3a is made of spheroidized carbon structural steel into a cylindrical blank, which is formed by cold rolling and forging, and extruded to one side to form the static side flange 5a. The work hardening caused by the extrusion can increase the root hardness of the stationary side flange 5a, thereby increasing the strength of the flange. On the other hand, during cold forging, the axially outer end of the inner ring main body 7a does not undergo major deformation, and its hardness is similar to that of the blank, so riveting can be easily performed to fix the inner ring element 8 .

To sum up, the rolling bearing unit 1a of this embodiment is characterized in that: the pitch circle diameter (PCD) of the inner row of balls 4b is larger than the pitch circle diameter of the outer row of balls 4a. Therefore, it is possible to increase the bearing capacity of the inner row of balls 4b while suppressing an increase in the weight of the bearing unit, thereby improving the durability of the bearing unit. In addition, no special parts are needed to fix the inner ring element 8 to the inner ring main body 7a, so the bearing structure is simplified, which is beneficial to reduce the weight and cost of the rolling bearing unit.

In the present embodiment, an internal space 15 is formed between the inner peripheral surface of the outer ring 2a and the outer peripheral surface of the inner ring 3a. As shown in FIG. 6, the axial inner opening of the internal space 15 is sealed with a seal ring 14b. The structure of the seal ring 14b is basically the same as that of the seal ring 14a in FIG. 4 . The step 20 is located at the junction of the cold-rolled surface and the ground sliding surface 21 on the axially outer surface of the stationary side flange 5a. The top end of the labyrinth sealing lip 33 a faces and is close to the step 20 . In addition, the seal ring 14b is fixed to the outer ring 2a having a rotating side raceway. Under the action of centrifugal force when the outer ring 2a rotates, the top end of the labyrinth sealing lip 33a deforms radially outward. Therefore, considering the effect of the centrifugal force, the gap between the top inner peripheral surface of the labyrinth sealing lip 33 a and the outer peripheral surface of the step 20 is smaller than that of the labyrinth sealing lip 33 in FIGS. 3 and 4 .

In addition, when the outer ring 2a is in a stationary state (when the car is parked), the top end of the labyrinth sealing lip 33a can also be slightly in contact with the step 20 (that is, they are in contact with each other but the interference is zero). Accordingly, when the vehicle is parked, the labyrinth seal lip 33a seals the sliding surface 21 to prevent entry of foreign matter. When the car is running, the labyrinth sealing lip 33a is separated from the step 20 under the action of centrifugal force to form a labyrinth seal without increasing the dynamic friction moment of the rolling bearing unit.

Fig. 7 is a modified example of the second embodiment. The combined sealing member 19 in this modified example is formed by a combination of a retaining ring 40 and a sealing ring 41 , and seals the opening of the inner space 15 in the axial direction. The retaining ring 40 is bent from a metal plate to form a substantially U-shaped ring in section, which includes:

Cylindrical portion 42 of the retaining ring;

The disc portion 43 of the retaining ring is formed by bending the cylindrical portion 42 of the retaining ring radially outward from the edge of the axial inner end;

The visor 44 is formed by bending the disc portion 43 of the stop ring from the radially outer end edge to the axially outer side.

The retaining ring 40 is externally fitted on the axial inner outer peripheral surface of the inner ring 3 a through the retaining ring cylindrical portion 42 in an interference fit manner, so that the retaining ring 40 is fixed to the inner ring 3 a. Also, the visor 44 is located radially outward of the axially inner outer peripheral surface of the outer ring 2a, while the top inner peripheral surface of the visor 44 faces the outer peripheral surface of the outer ring 2a.

The sealing ring 41 has a skeleton 45 made of sheet metal and a sealing material body 46 . The sealing material body 46 is bonded and fixed on the skeleton 45 . It includes:

a plurality of primary sealing lips (three are shown) 47a, 47b, 47c;

A visor-shaped labyrinth lip 51 constituting a labyrinth seal.

In addition, the skeleton 45 is bent from a metal plate to form a circular ring with a curved section, which includes:

sealing cylinder part 48;

The sealing disc part 49 is formed by bending the axially outer end of the sealing cylindrical part 48 radially inward;

The fitting disc portion 50 is formed by bending the axially inner end of the sealing cylinder portion 48 outward in the radial direction.

Therefore, the seal ring 41 with the skeleton 45 has its seal cylinder portion 48 embedded in the axially inner end portion of the outer ring 2a in an interference fit manner, and at the same time, the shaft of the fitted disc portion 50 The outer surface abuts against the axially inner end surface of the outer ring 2a, so that the seal ring 41 is fixed to the outer ring 2a.

In the above state, the top edge of the main sealing lip 47a contacts and slides on the axial outer surface of the disc portion 43 of the retaining ring;

On the other hand, the labyrinth lip 51 is located radially outside the main lip seal 47a, and protrudes axially inward (to the right in FIG. 7 ) from the outer peripheral edge of the axially inner end portion of the outer ring 2a. Moreover, the top end of the labyrinth sealing lip 51 and the axially outer surface of the disc portion 43 of the stop ring face and approach each other in the entire circumferential direction. Accordingly, a radial labyrinth seal with a labyrinth seal gap a is formed between the top end of the labyrinth seal lip 51 and the axially outer surface of the disc portion 43 of the stop ring. Furthermore, the radial labyrinth seal bends axially outward, and forms an axial labyrinth seal with a labyrinth seal gap b between the top outer peripheral surface of the labyrinth seal lip 51 and the inner peripheral surface of the brim 44 . Moreover, the relationship between the radial labyrinth seal gap a and the axial labyrinth seal gap b is: a<b.

Furthermore, in this embodiment, the top end of the labyrinth seal lip 51 is inclined axially inward to radially outward. At the same time, the top end of the visor 44 is inclined toward the axially outer side and radially outer side. Such a structure can make the muddy water entering the inner diameter side of the labyrinth sealing lip 51 flow radially outward along the inclined inner peripheral surface of the labyrinth sealing lip 51 under the action of the centrifugal force when the sealing ring 41 rotates, and then follow the inclination of the brim 44 The inner periphery is discharged toward the outer space. Therefore, foreign matter such as muddy water can be effectively prevented from entering the sealing space inside the main sealing lip 47a. Furthermore, it is also possible to prevent foreign matter from adhering to the outer peripheral surface of the main lip seal 47a, thereby preventing the movement of the main lip seal 47a from being impaired to reduce the sealing performance.

In the above-mentioned embodiment, the retaining ring 40 as the main sealing lip is fitted and fixed on the inner ring 3a. Compared with the structure of the sealing ring 14b shown in FIG. 6, in FIG. The main seal lip 47a extending inside can also be added, so that the sealing performance can be further improved. In addition, the labyrinth seal lip 51 can also contact and slide with the stop ring disc portion 43 in a light contact (contact with zero interference).

The structures and functions of other parts are the same as those of the first embodiment, so the same structures are marked with the same reference numerals, and no repeated text description is given.

[The third specific implementation mode]

Figures 8-10 show a third specific implementation manner. The rolling bearing unit supporting the wheel provided in this specific embodiment is an inner ring that rotates and is used to drive the wheel. It is characterized in that: a spline hole 26 is provided in the center of the inner ring 3b (inner ring main body 7b constitutes the inner ring 3b) having a rotating side raceway, and the axially outer end surface of the constant velocity joint member 27 is fixedly provided with a drive shaft. The spline shaft 28, the spline shaft 28 and the spline hole 26 are engaged with each other. In addition, the periphery of the axially outer end edge of the spline hole 26 on the inner peripheral surface of the inner ring 3 b abuts against the inner surface of the nut 29 . The method of installing on the vehicle is: engage the spline shaft 28 with the spline hole 26, screw the nut 29 and the external thread at the top of the spline shaft 28 together, and after further tightening, the inner ring 3b will pass through the nut 29 is fixed together with the spline shaft 28 and the constant velocity universal joint part 27.

The inner ring main body 7b constituting the inner ring 3b is provided with an inner ring outer raceway 10c at its axial middle part, and an inner ring with an inner ring inner raceway 10d is embedded on the outer peripheral surface of its axially inner end portion Element 8. The riveted part 9 formed after the axially inner end of the inner ring main body 7b is plastically deformed radially outward presses the inner ring element 8 tightly, so that the inner ring element 8 and the inner ring main body 7b are combined and fixed. In addition, the inner ring outer raceway 10c has a larger diameter than the inner ring inner raceway 10d.

The inner peripheral surface of the outer ring 2b is provided with double rows of outer ring raceways 6c, 6d. The outer ring outer raceway 6c has a larger diameter than the outer ring inner raceway 6d. A plurality of freely rolling balls 4c are provided between the outer raceway 6c of the outer ring and the outer raceway 10c of the inner ring, and a plurality of freely rolling balls are provided between the inner raceway 6d of the outer ring and the inner raceway 10d of the inner ring. 4d. The rows of balls 4c, 4d are respectively in contact with the inner and outer rings and given a pre-tightening force, and their contact angles are in a back-to-back combination. At the same time, the pitch circle diameter of the outer row of balls 4c is larger than the pitch circle diameter of the inner row of balls 4d. The structure of this embodiment not only prevents the rolling bearing unit from being enlarged, but also improves the bearing rigidity to ensure the stability of the vehicle when turning.

In this embodiment, the axially outer opening of the internal space 15 is sealed by the seal ring 14c, and the axially inner opening is sealed by the combined sealing member 19a. As shown in FIG. 9, the seal ring 14c is composed of a skeleton 30b and a sealing material body 31b. The skeleton 30b is formed by bending metal plates such as soft steel plates, which includes:

Fitting cylindrical part 34;

The disc portion 35a is formed by bending the edge of the axially outer end portion of the fitted cylindrical portion 34 radially outward;

The back and forth bending portion 36 is formed by bending the edge of the axially inner end portion of the fitting cylindrical portion 34 radially inward and then axially outward, in a U-shape;

The cylindrical portion 37 is formed by bending inwardly in the axial direction from the outer peripheral edge of the disk portion 35a.

The fitting cylindrical portion 34 is fitted and fixed to the inner peripheral surface of the axially outer end portion of the outer ring 2b by an interference fit. At the same time, the axially inner surface of the disc portion 35a is in contact with the axially outer end surface of the inner ring 2b through a part of the sealing material body 31b.

The sealing material body 31b is made of rubber-like elastic material, which is bonded and fixed with the frame 30b, and has main sealing lips 32a, 32b and a brim-shaped labyrinth sealing lip 33 forming a labyrinth seal. The front end edges of the main seal lips 32a and 32b are in sliding contact with the ground sliding surface 21 on the outer peripheral surface of the inner ring 3b over the entire circumferential direction.

The main sealing lip 32a is arranged at the position closest to the external space, the labyrinth sealing lip 33 is located radially outside of the main sealing lip 32a, and at the same time, the top end of the labyrinth sealing lip 33 is located radially outside of the step 20 And overlap with the step 20 in the radial direction. The top inner peripheral surface of the labyrinth sealing lip 33 is close to the outer peripheral surface of the step 20 in the entire circumferential direction. Thus, an axial labyrinth seal is formed between the inner peripheral surface of the top end of the labyrinth sealing lip 33 and the outer peripheral surface of the step 20 . In addition, the labyrinth lip 33 is inclined radially outward toward the axially outer side.

Moreover, the said sealing material body 31b covers the disk part 35a and the cylindrical part 37 of the said frame|frame 30b, and forms the visor 38. The inner diameter of the visor 38 is larger than the diameter of the outer peripheral surface of the axially outer end of the outer ring 2b, and the outer peripheral surface of the outer ring 2b, the axial inner surface of the disc portion 35a, and the inner peripheral surface of the visor 38 are in the entirety of the outer end of the outer ring 2b. The outer peripheral space is surrounded by a groove. Accordingly, it is possible to block external moisture from entering the inner side of the labyrinth sealing lip along the outer peripheral surface of the outer ring 2b. In addition, the sealing material body 31 covers the axially inner side of the disc portion 35a, and has ribs 39 on the entire circumference of the axially inner side surface of the disc portion 35a abutting against the axially outer end surface of the outer ring 2b. Accordingly, it is possible to prevent foreign matter such as muddy water from entering the internal space 15 through the fitting surface of the outer ring 2b and the sealing ring 14c.

In addition, as shown in FIG. 10 , the rolling bearing unit 1 b supporting the wheel provided by this embodiment further has a combined sealing member 19 a composed of a retaining ring 40 a and a sealing ring 41 a. The retaining ring 40a is bent from a metal plate to form an L-shaped ring, which includes a retaining ring cylindrical portion 42 and a retaining ring disc portion 43a. The retaining ring disc portion 43a is formed by bending the retaining ring cylindrical portion 42 from its axially inner end edge to radially outward. The cylindrical portion 42 of the retaining ring is externally embedded in the axially inner end portion of the inner ring 3b (the inner ring element 8 constituting the inner ring 3b together with the inner ring main body 7b) with an interference fit, and the retaining ring 40a It is then fixed on the inner ring 3b. In addition, the sealing ring 41a is composed of a skeleton 45a made of metal plate and an elastic material 46a. The elastic material 46a has a plurality of main sealing lips 47a, 47b, 47c. The frame 45 a is bent from a metal plate to form a ring with a substantially L-shaped cross-section, which includes a cylindrical portion 48 of a sealing ring and a disc portion 49 of the sealing ring. The sealing ring disc portion 49 is formed by bending the sealing ring cylindrical portion 48 from its axially outer end edge to the radially inner side. The cylindrical portion 48 of the sealing ring is embedded in the axially inner end portion of the outer ring 2b with an interference fit, so that the sealing ring 41a is fixed on the outer ring 2b. In the above state, the top end edge of the main sealing lip 47a is in sliding contact with the axially outer surface of the disc portion 43a of the retaining ring. At the same time, the main seal lips 47b and 47c are respectively in sliding contact with the outer peripheral surface of the stop ring cylindrical portion 42 over the entire circumferential direction.

In addition, the encoder 17a is adhered and fixed on the entire circumferential direction of the axial inner surface of the stop ring disc portion 43a constituting the stop ring 40a. The encoder 17a is a permanent magnet such as a disc-shaped rubber magnet or a plastic magnet formed by mixing magnetic powder into a polymer material such as rubber or synthetic resin. S poles and N poles are alternately provided. The encoder 17a encloses the outer peripheral edge of the disc portion 43a of the stop ring, and forms a labyrinth seal 52 between it and the inner peripheral surface of a part of the elastic material 46a covering the cylindrical portion 48 of the sealing ring. Furthermore, a thick-walled portion 53 is provided between the inner peripheral surface of the sealing ring cylindrical portion 48 and about half the outer diameter of the axially inner outer diameter of the sealing ring disc portion 49, and the thick-walled portion 53 is made of the elastic material 46a. A part, its axial thickness and radial thickness are greater than other parts. The axial inner end surface of the thick wall portion 53 is a disc-shaped stepped surface 54, and the section between the stepped surface 54 and the elastic material covering the inner surface of the top end of the cylindrical portion 48 of the sealing ring is a quarter of a circular arc. The outer diameter side curved surface 55 is smoothly connected. The radius of curvature of the section of the outer diameter side curved surface 55 is larger than the radial gap width of the labyrinth seal 52 . Accordingly, foreign matter that enters the outer diameter side space of the auxiliary seal lip 56 described later through the gap of the labyrinth seal 52 easily flows back into the labyrinth seal 52 .

Furthermore, the auxiliary sealing lip 56 extends from the radially inner end of the stepped surface 54 to the disc portion 43a of the retaining ring (the main sealing lips 47a-47c are integrated with the elastic material 46a). In addition, the auxiliary sealing lip 56 takes the stepped surface 54 as a root end, extends inward in the axial direction in a trumpet shape, and then makes sliding contact with the disc portion 43 a of the retaining ring. The outer peripheral surface at the root end of the auxiliary sealing lip 56 is smoothly connected with the stepped surface 54 by an inner diameter side curved surface 57 whose section is a quarter arc.

In order to make the auxiliary sealing lip 56 moderately easy to bend, and to make it easy for foreign matter entering the space on the outer diameter side of the auxiliary sealing lip 56 to flow back to the labyrinth seal 52 through the labyrinth seal 52 , it is necessary to properly limit the radius of curvature of the section of the inner diameter side curved surface 57 . Therefore, the sectional curvature radius of the inner diameter side curved surface 57 is set to be equal to or slightly larger than the thickness of the root end of the auxiliary seal lip 56 .

The auxiliary lip seal 56 is located on the outer diameter side of the main lip seal 47a called a side lip, and its purpose is to suppress adhesion of foreign matter to the main lip seal 47a, and high sealing performance is not required. However, it is important not to excessively increase the rotational resistance (dynamic friction moment) of the rolling bearing unit 1b equipped with the composite seal member 19a due to the provision of the auxiliary seal lip 56 . For this reason, the present embodiment suppresses an increase in kinetic friction torque due to the provision of the auxiliary seal lip 56 by the following means.

The cross-sectional shape of the auxiliary sealing lip 56 is wedge-shaped, and its thickness becomes smaller as it gets closer to the top edge. Such a design can reduce the stiffness of the top end of the auxiliary sealing lip 56 and suppress the increase of dynamic friction torque.

Furthermore, the thickness of the auxiliary sealing lip 56 is much smaller than that of the main sealing lip 47a. Specifically, the thickest portion (root end thickness) of the auxiliary seal lip 56 is 1/2 or less, preferably 1/3 or less, of the thinnest portion (root end thickness) of the main seal lip 47a. However, considering the convenience of forming, it is set to be more than 1/5. Such a design can reduce the rigidity of the auxiliary sealing lip 56 as a whole, and suppress the increase of the dynamic friction torque.

Furthermore, after the sealing ring 41a and the blocking ring 40a are assembled in place, the interference of the auxiliary sealing lip 56 is much smaller than the interference of the main sealing lip 47a. Such a design can make the elastic deformation amount (axial compression amount) of the auxiliary sealing lip 56 much smaller than the elastic deformation amount of the main sealing lip 47a, and at the same time, it can restrain the axis between the top edge of the auxiliary sealing lip 56 and the disc portion 43a of the retaining ring. Sliding contact stress between the outward side surfaces can suppress an increase in sliding resistance.

In addition, because the auxiliary sealing lip 56 is not required to have a high degree of sealing performance, when the car is turning, the central axis of the sealing ring 41a and the central axis of the retaining ring 40a will be inclined to each other, so even if the top of the auxiliary sealing lip 56 moves from the retaining ring disc It does not matter if the axially outer surface of the portion 43a is slightly raised (the interference is zero or there is a slight gap). In addition, the tip of the auxiliary seal lip 56 and the axially outer surface of the stop ring disc portion 43a may face each other with a slight gap in the entire circumferential direction.

In short, an auxiliary sealing lip 56 is provided between the main sealing lip 47 a and the labyrinth seal 52 , and an external space 58 is provided outside the auxiliary sealing lip 56 where it communicates with the labyrinth seal 52 . Two radially inner and outer edges of the stepped surface 54 constituting the outer space 58 are smoothly connected to two radially inner and outer peripheral surfaces of the outer space 58 through the outer radial side curved surface 55 and the inner radial side curved surface 57 respectively. Furthermore, the outer peripheral surface of the auxiliary seal lip 56 connected to the radially inner curved surface 57 is inclined toward the labyrinth seal 52 toward the tip thereof. Such a structure can change the flow direction of the foreign matter scraped into the outer space 58 after passing through the labyrinth seal 52 violently, and flow back to the labyrinth seal 52 .

To sum up, the rolling bearing unit 1b supporting the wheel provided by this embodiment is equipped with a combined sealing member 19a, so it can effectively prevent muddy water and other external foreign matter from passing through the sealing lip between the retaining ring 40a and the sealing ring 41a, and entering the main sealing lip. 47a inside the sealed space. In particular, it should be mentioned that among the main sealing lips 47a-47c, the one closest to the labyrinth seal 52 is the main sealing lip 47a. When foreign matter adheres to the outer peripheral surface of the main sealing lip 47a, the movement of the main sealing lip 47a will be affected, and its sealing performance will also be reduced. The structure provided by this embodiment can prevent foreign matter from adhering to the outer peripheral surface of the main seal lip 47a. That is to say, in the structure provided by this embodiment, since the labyrinth seal 52, the stepped surface 54 and the auxiliary sealing lip 56 are provided, the stepped surface 54 separates the axially outer side of the external space 58, and the auxiliary sealing lip 56 separates the outer space 58 from the outer space. Internally spaced. Therefore, entry of foreign matter into the inner space of the auxiliary seal lip 56 is suppressed.

The structures and functions of other parts are the same as those of the first embodiment, so the same structures are marked with the same reference numerals, and no repeated text description is given.

Industrial Applicability

The rolling bearing unit provided by the utility model is especially suitable for automobile wheels.

Claims (1)

1. A rolling bearing unit for supporting a wheel, comprising: an outer ring having an outer ring raceway on its inner peripheral surface; an inner ring arranged coaxially with the outer ring, and having an inner ring raceway on a portion of the outer peripheral surface of the inner ring opposite to the outer ring raceway; a plurality of rolling elements freely rolling between the outer ring raceway and the inner ring raceway; a flange integral with the inner ring and extending radially outward from the outer peripheral surface of the inner ring by forging; a seal ring sealing an end opening of an internal space between an inner peripheral surface of the outer ring and an outer peripheral surface of the inner ring, It is characterized by: A sliding surface formed after grinding is provided on the outer peripheral surface of the inner ring; the sealing ring is composed of a skeleton fixed at the end of the outer ring and an elastic sealing material body adhered to the skeleton; the elastic sealing The material body has at least one main sealing lip that contacts and slides with the sliding surface in the entire circumferential direction, and a labyrinth sealing lip is provided on the radially outer side of the main sealing lip, and the top end of the labyrinth sealing lip is in contact with the flange. The side faces of the flange are opposite and close to each other in the circumferential direction, thereby forming a labyrinth seal with the side faces of the flange; There is a forged surface formed by cold rolling on the side of the main part of the flange, and there is a step between the forged surface and the sliding surface, and the top end of the labyrinth sealing lip is located on the radially outer side of the step and The steps overlap radially.

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