Sealing assembly for rolling bearing and rolling bearing having such sealing assembly

Abstract

The invention relates to a sealing arrangement for a rolling bearing, in which a first angle ring for fastening to an outer ring of the bearing and a second angle ring for fastening to an inner ring of the bearing are arranged in such a way that they define an annular sealing chamber in the shape of an annular sealing box, an axial dynamic sealing part is arranged in the sealing cavity, and two radial sealing gaps are formed between the angle rings. Here, the sealing box has a radial structural height of less than 3.2 mm, which corresponds to the distance between the outer diameter of the first angle ring and the inner diameter of the second angle ring, and an axial structural width of less than 1.6 mm, which corresponds to the axial distance of the axially outer sides of the angle rings facing away from each other.

Description

Field of the Invention

[0001] The present invention relates to a sealing assembly for a rolling bearing. The present invention also relates to a rolling bearing having such a sealing assembly. The present invention also relates to a pedal support assembly having at least one such rolling bearing, the pedal support assembly being for supporting the pedal crankshaft of an electrically drivable two-wheeler. Background Art

[0002] A pedal support assembly for a bicycle is known from DE 10 2015 216 168 B3. Here, rolling bearings are arranged spaced apart axially from one another, and the rolling bearings are each fixed to the bicycle frame by rolling bearing outer rings. A pedal shaft is inserted into the inner rings of the rolling bearings. On one end side of the rolling bearing, an additional external sealing ring washer is arranged between the rolling bearing outer ring and the rolling bearing inner ring. Summary of the Invention

[0003] Accordingly, it is an object of the present invention to improve a sealing assembly, a rolling bearing, and a pedal support assembly of the aforementioned type, which can ensure a high degree of sealing and can be easily installed with a small structural space requirement.

[0004] This object is achieved by the features of claim 1 and alternatively by the features of claim 7 or 10. Other advantageous and claimed design solutions are derived from the corresponding dependent claims, the description, and the drawings.

[0005] Accordingly, a sealing assembly for a rolling bearing is proposed, wherein a first angular ring for fixing to the bearing outer ring and a second angular ring for fixing to the bearing inner ring are arranged such that they define an annular sealing chamber, the sealing chamber being in the shape of an annular sealing box, and an axial dynamic seal is arranged in the sealing chamber and two radial sealing gaps are formed between the angular rings. Here, the sealing box has a radial structural height of less than 3.2 mm and an axial structural width of less than 1.6 mm, the radial structural height corresponding to the spacing between the outer diameter of the first angular ring and the inner diameter of the second angular ring, and the axial structural width corresponding to the axial spacing between the axially facing outer sides of the angular rings.

[0006] A high degree of sealing is achieved by the double labyrinth effect of the very narrow sealing gaps. In addition, the sealing chamber defined by the sealing box is protected against direct contact with splashing water and pressurized water, such that the dynamic seal arranged in the sealing chamber ensures a high degree of additional sealing. Therefore, the proposed sealing assembly forms an efficient seal as a cartridge seal, the cartridge seal having a particularly small structural space requirement due to its small structural height and width and being applicable in thin-ring bearings. In addition, the sealing box can be easily installed, in particular by press-fitting, with the outer diameter of the first angular ring at the inner diameter of the bearing outer ring and the inner diameter of the second angular ring at the outer diameter of the bearing inner ring.

[0007] The sealing effect can preferably be further improved by the fact that the radial sealing clearances respectively have a radial clearance size of 0.3 mm or less than 0.3 mm.

[0008] In a preferred design of the present invention, the sealing cartridge can be fixed particularly simply with the outer diameter of the axially extending axial arm of the first angular ring at the inner diameter of the bearing outer ring and with the inner diameter of the axially extending axial arm of the second angular ring at the outer diameter of the bearing inner ring, preferably by press-fitting.

[0009] In a further improvement of the present invention, a first radial sealing clearance is formed between the free ends of the axial arm of the first angular ring and the radially outwardly extending radial arm of the second angular ring. Preferably, a second radial sealing clearance is formed here between the free end of the radially inwardly extending radial arm of the first angular ring and the axial arm of the second angular ring. In this way, at the first sealing clearance, the sealing cartridge can be sealed relative to the environment on the outside and dirt, as well as splashing water and compressed water, can be prevented from entering the sealing cavity. At the second radial sealing clearance, the rolling bearing can be further sealed relative to the bearing inner space, so that the rolling bearing is sealed relative to the environment by a double labyrinth effect. In addition, the radial arm of the second angular ring can simultaneously form a centrifugal disk, via which dirt and water can be thrown out by centrifugal force during rotation.

[0010] The dynamic sealing part can preferably be integrated into the sealing cavity of the sealing cartridge in a space-saving manner in a simple way as a sealing lip, and the sealing lip extends from the radial arm of the first angular ring to make axial sealing contact with the axial sealing surface on the radial arm of the second angular ring.

[0011] In order to simply fix the dynamic sealing part on the radial arm of the first angular ring, its free end is gradually narrowed axially with a reduced wall thickness, so that the dynamic sealing part can be fixed particularly space-savingly on both axial sides of the free end and connected thereto, preferably fixed on the free end as an elastomeric sealing part by vulcanization or casting.

[0012] The object according to the present invention is also achieved by a rolling bearing having the aforementioned sealing assembly. It is hereby stipulated that the sealing assembly has a sealing cartridge for sealing the radial bearing clearance formed between the bearing rings. Thereby, the above-mentioned advantages are achieved.

[0013] In addition, the rolling bearing can be implemented in a simple way as a thin-ring bearing with a small axial bearing structural width and a small radial structural height, which has a sealing cartridge as an efficient seal on one side relative to the environment.

[0014] Preferably, the axial bearing structural width is 7 mm or less than 7 mm.

[0015] Preferably, the rolling bearing has a radial structural height of 13 mm or less than 13 mm, where the radial structural height is the radial distance between the inner diameter of the bearing inner ring and the outer diameter of the bearing outer ring.

[0016] Preferably, in order to further save structural space, the bearing inner ring has a radial wall thickness of less than 1.2 mm in the region of the fixed seal box.

[0017] Alternatively, it is conceivable that the bearing outer ring has a radial wall thickness of less than 1.2 mm in the region of the fixed seal box.

[0018] In another preferred design of the proposed rolling bearing, at the outer diameter of the bearing outer ring, a sealing ring for sealing the bearing seat on a position-fixed component, especially a housing, is arranged in a radial recess, and the bearing outer ring has a radial wall thickness of less than 1.2 mm in the region of the recess. Preferably, the recess with the sealing ring is arranged in the intermediate region between the axial ends of the bearing outer ring and has the same height as the rolling element track formed on the inner diameter of the bearing outer ring.

[0019] Thus, an additional sealing part can be provided at the bearing outer ring of the rolling bearing to seal the bearing seat of the rolling bearing without additional structural space.

[0020] In another particularly space-saving and advantageous manner, balls with a ball diameter of 3.5 mm or less than 3.5 mm are provided as rolling elements.

[0021] It is also particularly advantageous that the rolling element cage for guiding the rolling elements is arranged such that there is a minimum possible radial clearance between the rolling element cage and the inner diameter of the bearing outer ring and the outer diameter of the bearing inner ring, and the radial clearance has a clearance width of 0.5 mm or less than 0.5 mm. Thereby, a shielding effect of preventing dirt particles from entering from the internal space is achieved on the axial inner side of the rolling bearing facing the internal space to be sealed. At the same time, lubricating oil is prevented from overflowing from the rolling bearing.

[0022] The aforementioned rolling bearing can have other features in the description of the sealing assembly described above.

[0023] The object of the present invention is also achieved by a pedal support assembly for supporting the pedal crankshaft of an electrically drivable bicycle, the pedal support assembly having at least one of the aforementioned rolling bearings. Thus, the above advantages are achieved. The pedal assembly can have other features in the description of the aforementioned rolling bearing and the sealing assembly described at the beginning. Description of the Drawings

[0024] Other features claimed in the present invention are derived from the following description and from the drawings further explaining the present invention. The drawings are as follows:

[0025] Figure 1 shows a sealing assembly for a rolling bearing according to the present invention,

[0026] Figure 2 shows Figure 1 a partially enlarged sectional view of

[0027] Figure 3 a sectional view of a rolling bearing having the sealing assembly,

[0028] Figure 4 a perspective view of a rolling bearing having the sealing assembly,

[0029] Figure 5 shows a pedal support assembly for an electrically drivable two-wheeler according to the present invention,

[0030] Figure 6 shows a perspective sectional view of the pedal support assembly. Detailed Description

[0031] Exemplary views in the drawings show a sealing assembly 1 for rolling bearings 2, 3 according to the present invention and rolling bearings 2, 3 having such a sealing assembly 1 according to the present invention. The drawings also exemplarily show a pedal support assembly for supporting a pedal crankshaft 31 of an electrically drivable two-wheeler, in particular a so-called electric bicycle or a so-called pedelec.

[0032] According to Figure 1 , the sealing assembly 1 has two metal corner rings 4, 5 made of sheet metal. As Figure 1 and Figure 2 shown, the corner rings are arranged between the rolling bearings 2, 3 for sealing the radial bearing clearance S formed between the bearing outer ring and the inner ring 6, 7 relative to the environment. The bearing outer ring and the inner ring 6, 7 are arranged coaxially with respect to the bearing axis 28.

[0033] The corner rings 4, 5 are each configured with two arms 8, 9 and 10, 11, and the cross-sections of the arms are arranged at right angles to each other in an L-shape. The first corner ring 4 has an axial arm 6 extending in the axial outer direction with a free end 12 and a radial arm 9 extending in the radial inner direction with a free end 13 for fixing to the bearing outer ring 6. The second corner ring 5 has an axial arm 6 extending in the axial inner direction with a free end 14 and a radial arm 9 extending in the radial inner direction with a free end 15 for fixing to the bearing inner ring 7.

[0034] The angle rings 4, 5 are arranged such that the angle rings define an annular sealing cavity 16 therebetween with their arms 8, 9 and 10, 11, in the form of an annular sealing box 17. The sealing box 17 is axially pressed onto the inner diameter of the outer bearing ring 6 (i.e., the outer circumference of the bearing shoulder 19 of the outer bearing ring 6) by its outer diameter (i.e., the outer circumference of the axial arm 8 of the first angle ring 4) and onto the outer diameter of the inner bearing ring 7 (i.e., the outer circumference of the bearing shoulder 20 of the inner bearing ring 7) by its inner diameter (i.e., the inner circumference of the axial arm 10 of the second angle ring 5).

[0035] Here, the sealing box forms a centrifugal disk with the axially outer side 21 facing the environment of the radial arm of the second angle ring 5. Through the centrifugal disk, dirt and water can be thrown out of the environment due to the centrifugal force generated during rotation.

[0036] The angle rings 4, 5 form two radial sealing gaps 22, 23 with each other. The first radial sealing gap 22 is formed between the free end 15 of the axial arm 8 of the first angle ring 4 and the radial arm 11 of the second angle ring 5. The second radial sealing gap 23 is formed between the free end 13 of the radial arm 9 of the first angle ring 4 and the axial arm 10 of the second angle ring 5. The first sealing gap 22 seals the sealing box 17 relative to the environment on the outside and prevents dirt, splash water and compressed water from entering the sealing cavity. The second radial sealing gap 23 further seals the rolling bearing 2 relative to the bearing inner space, so that the rolling bearings 2, 3 are additionally sealed relative to the environment through a double labyrinth effect.

[0037] An axially moving seal 18 is arranged in the sealing cavity 16 defined by the sealing box 17. The axially moving seal is configured as an axially sealing lip preferably made of an elastomer, which extends axially in sealing contact from the radial arm 9 of the first angle ring 4 to the axial sealing surface 25 on the axially inner side of the radial arm 11 of the second angle ring 5 in the sealing cavity 16. Preferably, for the sealing contact of the sealing lip 18, the sealing surface 25 has a special surface to reduce the contact friction.

[0038] The free end 13 of the radial arm 8 of the first angle ring 4 is retracted with a reduced wall thickness d and narrowed at the axially two sides 24, 32, so that the sealing lip 18 is firmly connected and fixed on both sides in a space-saving manner at the free end 13, preferably by vulcanization or casting on this free end.

[0039] Here, the sealing box 17 has a radial structural height h less than 3.2 mm, and this radial structural height corresponds to the radial spacing between the outer diameter of the axial arm 8 of the first angle ring 4 and the inner diameter of the axial arm 10 of the second angle ring 5.

[0040] Furthermore, the axial structural width b of the sealing cartridge 17 is designed to be less than 1.6 mm. This axial structural width corresponds to the axial spacing between the axial outer sides 21, 24 of the radial arms 9, 11 of the corner rings 4, 5, respectively, which face away from the sealing cavity 16. In this way, the sealing assembly 1 forms an efficient seal, which is a cartridge seal with particularly small structural space requirements.

[0041] The rolling bearings 2, 3 are preferably implemented as deep groove ball bearings as shown in Figure 1 , 3 and 4. The rolling bearings are torsionally connected to the outer diameter of the shafts 29, preferably the pedal crankshaft of a bicycle as shown in Figure 4 and Figure 5 , by means of the inner diameter of the bearing inner rings 7. The rolling bearings 2, 3 are configured as thin ring bearings with a bearing structural width B preferably of 7 mm or less. This bearing structural width is measured between the axial end sides of the rolling bearing 2 as shown in Figure 1 .

[0042] The sealing cartridge 17 is preferably fixed by means of a press fit, with the outer diameter of the axial arm 8 of the first corner ring 4 at the inner diameter of the bearing shoulder 19 of the bearing outer ring 6 and with the inner diameter of the axial arm 10 of the second corner ring 5 at the outer diameter of the bearing shoulder 20 of the bearing inner ring 7.

[0043] To accommodate the sealing cartridge 17, the bearing inner ring 7 has a radial wall thickness W of less than 1.2 mm in the region of the bearing shoulder 20. For this purpose, the bearing shoulder 20 is provided, for example as a groove, with a radially inwardly directed axial edge at the outer diameter towards the free outside.

[0044] At the outer diameter of the bearing outer ring 6, a sealing ring 27 in the form of an O-ring is arranged in a radially recessed portion 26 implemented as a groove. The sealing ring serves to seal the bearing housing radially at a component fixed in a position not shown. In this case, the bearing outer ring 6 has a radial wall thickness L of less than 1.2 mm in the region of the recess 26. Preferably, the recess 26 with the sealing ring 27 is arranged in an intermediate region between the axial ends of the bearing outer ring 6, at the height of the rolling element raceway 27 implemented at the inner diameter of the bearing outer ring 6. Thus, the rolling bearings 2, 3 can be implemented with an additional sealing portion 27 for sealing the bearing housing without additional structural space.

[0045] The bearing inner ring 7 is preferably fixed to the shaft 29, preferably the pedal crankshaft of a bicycle, by means of a press fit as shown in Figure 4 and Figure 5 . A seal is simultaneously achieved at the press fit between the bearing inner ring 7 and the shaft 29.

[0046] To further reduce the structural space, the ball diameter D of the rolling elements 28 is reduced. The ball diameter D is preferably 3.5 mm or less.

[0047] Therefore, the rolling bearings 2, 3 can be used as thin-ring bearings, having a small bearing width B and a small radial height H, and having the sealing device 1 and the seal housing 17 as a one-sided high-performance seal towards the external environment. The radial structural height H of the rolling bearings 2, 3 is preferably 13 mm or less than 13 mm, and the radial structural height corresponds to the radial spacing between the inner diameter of the bearing inner ring 7 and the outer diameter of the bearing outer ring 6.

[0048] The rolling element cage 35 for guiding the rolling elements 28 is implemented such that there is a minimum possible radial clearance S1 with respect to the inner diameter of the bearing outer ring 6 and with respect to the outer diameter of the bearing inner ring 7, respectively. Here, in the ideal coaxial arrangement of the rolling element cage 35 with respect to the bearing outer ring 6 and the bearing inner ring 7, the radial clearance S1 preferably has a clearance width of 0.5 mm or less than 0.5 mm, respectively. Thus, a shielding effect is achieved on the axial inner side of the rolling bearings 2, 3 towards the internal space to be sealed, preventing dust particles (especially those generated from the wear of the motor and the transmission) from entering the internal space. At the same time, the outflow of lubricating oil from the rolling bearings 2, 3 is avoided.

[0049] Figure 4 and Figure 5 shows the proposed pedal support assembly and its installation position, by way of example, on an electrically drivable two-wheeler, in particular an electric bicycle or a pedelec. In Figure 4 the pedal support assembly has a housing 34, pedal bearings in the form of two of the aforementioned rolling bearings 2, 3, a motor not shown, and a transmission not shown. The housing 34 is connected to the frame 35 of the two-wheeler, for example, a bicycle frame. The pedal crankshaft 31 is arranged transversely to the longitudinal axis of the two-wheeler and passes through the housing 34 with its axial ends. The pedal crankshaft is connected to the pedal cranks 36, 37 of the two-wheeler at its axial ends, respectively. The output at the pedal crankshaft 31 is achieved via a drive wheel 38 implemented as a sprocket.

[0050] Figure 5 shows a partial cross-sectional view of the pedal support assembly. The pedal crankshaft 31 is supported in the housing 34 via the aforementioned rolling bearings 2, 3 at its axial end sections, respectively. For this purpose, the outer ring 6 of the corresponding rolling bearings 2, 3 is supported on the inner diameter of the bearing seat 39, which is formed on the inner side of the housing 34, by its outer diameter.

[0051] The two-wheeler can be driven via the pedal cranks 36, 37 ( Figure 4 ) and the pedal crankshaft 31 and via the motor.

[0052] The housing 34 is enclosed relative to the environment. At the penetration part of the pedal crankshaft 31, it is sealed relative to the environment by rolling bearings 2, 3 with the aforementioned sealing assembly 1. Thus, the rolling bearings 2, 3, the electric motor and the transmission are protected in the housing 34 from moisture and dirt particles from the environment.

[0053] List of Reference Numerals

[0054] 1 Sealing assembly

[0055] 2 Rolling bearing

[0056] 3 Rolling bearing

[0057] 4 First angular ring

[0058] 5 Second angular ring

[0059] 6 Bearing outer ring

[0060] 7 Bearing inner ring

[0061] 8 Axial arm of the first angular ring

[0062] 9 Radial arm of the first angular ring

[0063] 10 Axial arm of the second angular ring

[0064] 11 Radial arm of the second angular ring

[0065] 12 Free end of the axial arm of the first angular ring

[0066] 13 Free end of the radial arm of the first angular ring

[0067] 14 Free end of the axial arm of the second angular ring

[0068] 15 Free end of the radial arm of the second angular ring

[0069] 16 Sealing cavity

[0070] 17 Sealing box

[0071] 18 Dynamic sealing part, sealing lip

[0072] 19 Bearing shoulder of the bearing outer ring

[0073] 20 Bearing shoulder of the bearing inner ring

[0074] 21 Axial outside

[0075] 22 Radial sealing gap

[0076] 23 Radial sealing gap

[0077] 24 Axial outside

[0078] 25 Axial sealing surface

[0079] 26 Axial recess, groove at the outer diameter of the bearing outer ring

[0080] 27 Sealing ring, sealing part

[0081] 28 Bearing axis

[0082] 29 Raceway for rolling elements

[0083] 30 Rolling element, ball

[0084] 31 Shaft, pedal crankshaft

[0085] 32 Axial inner side of the radial arm of the first angular ring

[0086] 33 Rolling element cage

[0087] 34 Position-fixed component, housing

[0088] 35 Bracket, bicycle frame

[0089] 36 Pedal crank

[0090] 37 Pedal crank

[0091] 38 Driving wheel

[0092] 39 Bearing housing

[0093] S Radial bearing clearance

[0094] d Reduced wall thickness of the radial arm of the first angular ring

[0095] h Radial structural height of the seal box

[0096] b Axial structural width of the seal box

[0097] B Axial bearing structural width

[0098] W Reduced radial wall thickness of the bearing inner ring

[0099] L Reduced radial wall thickness of the bearing outer ring

[0100] D Ball diameter of the rolling element

[0101] H Radial structural height

[0102] S1 Radial clearance

Claims

1. A sealing assembly (1) for a rolling bearing (2, 3), characterized in that: A first angle ring (4) for fixing on a bearing outer ring (6) and a second angle ring (5) for fixing on a bearing inner ring (7) are arranged so that they define an annular sealing chamber (16), the sealing chamber (16) being in the form of an annular sealing box (17), and an axial dynamic sealing portion (18) being arranged in the sealing chamber (16), and two radial sealing gaps (22, 23) being formed between the angle rings (4, 5), wherein the sealing box (17) has a radial structural height (h) of less than 3.2 mm and an axial structural width (b) of less than 1.6 mm, the radial structural height being equivalent to the distance between the outer diameter of the first angle ring (4) and the inner diameter of the second angle ring (5), and the axial structural width being equivalent to the axial distance between the axial outer sides (21, 24) of the angle rings (4, 5) which are away from each other.

2. The sealing assembly according to claim 1, characterized in that: The radial sealing gaps (22, 23) each have a radial gap size of 0.3 mm or less.

3. The sealing assembly according to any one of claims 1 or 2, characterized in that: The sealing box (17) can be pressed into the inner diameter of the bearing outer ring (6) with the outer diameter of the axial support arm (8) extending in the axial direction of the first angle ring (4), and can be fixed by pressing into the outer diameter of the bearing inner ring (6) with the inner diameter of the axial support arm (10) extending in the axial direction of the second angle ring (5).

4. The sealing assembly according to claim 3, characterized in that: A first radial sealing gap (22) is formed between the axial branch arm (8) of the first angle ring (4) and the free end (15) of the radial branch arm (11) of the second angle ring (5) extending radially outward, and a second radial sealing gap (23) is formed between the free end (13) of the radial branch arm (9) of the first angle ring (4) extending radially inward and the axial branch arm (10) of the second angle ring (5).

5. The sealing assembly according to claim 4, characterized in that: The dynamic sealing portion (18) is a sealing lip, which extends from the radial branch arm (9) of the first angle ring (4) to axially seal in contact with the axial sealing surface (25) on the radial branch arm (11) of the second angle ring (5).

6. The sealing assembly according to claim 5, characterized in that The free end (13) of the radial support arm (9) of the first angle ring (4) gradually narrows on the axial side (24, 32) with a gradually decreasing wall thickness, and the dynamic sealing part (18) is fixedly connected to the free end on the two axial sides (24, 32) of the free end (13).

7. Rolling bearing (2, 3) having a sealing assembly according to any one of claims 1 to 6, wherein: The sealing assembly (1) comprises a sealing box (17) for sealing a radial bearing gap (S) formed between bearing rings (6, 7).

8. The rolling bearing (2, 3) according to claim 7, characterized in that The bearing inner ring (7) has a radial wall thickness (W) of less than 1.2 mm in the region of the sealing box (17).

9. The rolling bearing (2, 3) according to claim 7 or 8, characterized in that A sealing ring (27) for sealing a bearing seat (39) on a fixed component (39) is arranged in a radial recess (26) at the outer diameter of the bearing outer ring (6), and the bearing outer ring (6) has a radial wall thickness (L) of less than 1.2 mm in the region of the recess (6).

10. A pedal bearing assembly for mounting a pedal crankshaft (31) of an electrically drivable two-wheeled vehicle, the pedal bearing assembly comprising at least one rolling bearing (2, 3) according to any one of claims 7 to 9.

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