EP3821145A1

EP3821145A1 - Bearing arrangement

Info

Publication number: EP3821145A1
Application number: EP19724797.6A
Authority: EP
Inventors: Volker EHLERS
Original assignee: Ebm Papst St Georgen GmbH and Co KG
Current assignee: Ebm Papst St Georgen GmbH and Co KG
Priority date: 2018-11-23
Filing date: 2019-05-14
Publication date: 2021-05-19
Also published as: CN112867869B; CN112867868A; WO2020104075A1; CN112867868B; WO2020104073A1; US20210348647A1; CN112840134A; KR20210093230A; EP3833875A1; EP3824188A1; KR20210096066A; US20210355946A1; EP3833875B1; CN210660659U; CN112867869A; US11781591B2; CN210565190U; DE202019102714U1; CN210660710U; WO2020104074A1

Abstract

The invention relates to a bearing arrangement designed as a fixed/floating bearing for a rotor of a fan, having a bearing tube, a compression spring, a shaft arranged coaxially with respect to the bearing tube and two identically formed ball bearings arranged between the bearing tube and the shaft, each ball bearing having an inner ring and an outer ring, wherein multiple different fit zones are formed axially along the bearing tube, wherein, in a first axial fit zone, one of the ball bearings as a fixed bearing is attached by its inner ring on the shaft and its outer ring is fixed with a press fit on a continuous, shoulder-free portion of the bearing tube and, in a second axial fit zone, another of the ball bearings as a floating bearing is attached by its inner ring to the shaft and its outer ring is axially displaceably arranged with a clearance fit on a continuous, shoulder-free portion of the bearing tube, wherein the compression spring is arranged in a third axial fit zone and, exerting a preload against the outer rings of the ball bearings, is positioned axially between the ball bearings and is designed to eliminate bearing play of the floating bearing.

Description

Storage arrangement

Description:

The invention relates to a bearing arrangement designed as a fixed-loose bearing for a rotor of a fan.

In the prior art it is known to use bearing tubes with fixed-floating bearing arrangements for use with cantilevered shaft loads. As a rule, a bearing tube with an inner shoulder or a geometrical shoulder for fitting a bearing is provided for bracing the bearings in an O arrangement. The first bearing is inserted into the bearing tube from one axial side, a spring and the second bearing from the other axial side. Both inner rings of the bearings are firmly connected to the shaft to be supported. The bearing assembly is up to the fleas the self-supporting preload. If the outer ring of the first bearing is fixed to it, for example by caulking, gluing or a locking ring, the bearing is defined in all directions.

With bearing tubes of this type, the bearings are machined and inserted from two sides. In addition, a geometric shoulder should be seen, which is not always desired. Furthermore, the coaxiality of the bearing seats is not optimal due to the bilateral processing

The invention has for its object to provide a bearing arrangement for a rotor of a fan with improved coaxiality of the bearing seats and simplified installation options from a single axial side.

This object is achieved by the combination of features according to claim 1.

According to the invention, a bearing arrangement is designed as a fixed-loose bearing for a rotor of a fan, with a La gerrohr, a compression spring, a shaft arranged coaxially to the bearing tube and two arranged between the bearing tube and the shaft, identically designed ball bearings each with inner ring and outer ring. Several different fit zones are formed axially along the bearing tube. In a first axial fit zone, one of the ball bearings is fixed as a fixed bearing with its inner ring on the shaft and its outer ring is fixed to a continuous, step-free section of the bearing tube with an interference fit. In a second axial fit zone, another of the ball bearings is attached as a floating bearing with its inner ring to the shaft and its outer ring is axially displaceably arranged with a clearance fit on a continuous, step-free section of the bearing tube. The compression spring is arranged in a third axial fit zone and is fer ner a preload against the outer rings of the ball bearing exerting axially positioned between the ball bearings and designed to eliminate a bearing play of the floating bearing. For this purpose, the compression spring is selected so that it has a spring force sufficient for the corresponding bearing.

The solution according to the invention dispenses with geometrical shoulders or contact shoulders on the bearing tube for the bearings, but instead provides different fitting zones for the two bearings, on the one hand as a press fit and on the other hand as a clearance fit. This enables a fully axial single-sided machining and assembly of the bearings. The coaxiality of the two bearing seats is also optimized.

The assembly is simplified because the fixed bearing, the compression spring and the floating bearing are fed from the same side and only easily monitored press processes can be used. Also no additional parts such as circlips or additives such as glue are required.

The different fit zones are preferably determined by under different tolerance zones of the inner diameter of the bearing tube. There is a clearance fit to the outer ring in the area of the compression spring and the floating bearing. In the area of the fixed bearing there is a press fit to the outer ring of the bearing. The bearing arrangement uses an outer ring-braced O arrangement

In one embodiment, the bearing arrangement provides that the third axial fit zone in the region of the compression spring corresponds to the second axial fit zone. This means that only two different fit zones need to be provided. A coarser tolerance tolerance than in the floating bearing is possible in the area of the spring.

Furthermore, an advantageous embodiment of the bearing arrangement is characterized in that an axial fit length L1 of the first fit zone of the fixed bearing is determined, that is 0.35 ^» L1 ^ D <0.5 ^» L1, where D is a Bearing tube inner diameter of the bearing tube is. In addition, an axial fit length L2 of the second fit zone of the floating bearing is preferably determined, that is 0.35 · T2 <0 <0.5 · ί2. This small axial length of the fit zones reduces the machining effort to small axial sections. The third fit zone of the compression spring is always axially between the two fit zones of the press and play fit of the two ball bearings.

In a development of the bearing arrangement, the first and second fit zones each adjoin axial edge sections of the bearing tube. Your position is therefore clear and easy to determine.

The entire axial holding force must be borne by the press connection of the outer ring of the fixed bearing to the bearing tube. In order to ensure this in a wide temperature range, a material is selected for the bearing tube that has a very similar expansion coefficient as the material of the ball bearing outer rings. In a preferred embodiment, the material of the outer rings of the ball bearings is even identical to a material of the bearing tube, for example steel.

A favorable solution also provides that the outer rings of the ball bearings and the bearing tube are made of soft magnetic steel, since unmagnetic, austenitic steels have an expansion coefficient that is too high.

For the shaft to be supported, the coefficient of expansion is of minor importance and may differ from that of the bearing tube. However, it is determined in such a way that it is similar to the coefficient of expansion of the ball bearing inner rings, that there is no impairment of the press fit or an inadmissible change in the radial internal clearance of the ball bearing.

For use with a fan, a version of the storage arrangement is also advantageous in which a collar is formed integrally in one piece in the bearing tube on an axial end portion of the bearing tube and has a receiving space for inserting a fan wheel. In addition to the bearing function, the bearing tube can therefore also determine a receptacle for the fan wheel and contribute to a compact construction with a small installation space and a small number of parts. The disclosure is thus also directed to a fan with the bearing arrangement described above.

Other advantageous developments of the invention are characterized in the subclaims or are shown below together with the description of the preferred embodiment of the invention with reference to the figures. Show it:

Fig. 1 is a perspective view of a cut layer

arrangement of a rotor of a fan; Fig. 2 shows another embodiment of a bearing arrangement of a

Rotor of a fan in a cut perspective view;

Fig. 3 shows a fan with a bearing arrangement in a sectional view.

Figures 1 and 2 show two embodiments of storage arrangement 1 executed as a fixed-floating bearing for a rotor 11 of a ventila gate.

Referring to FIG. 1, in a perspective sectional view, the bearing arrangement 1 with the bearing tube 2, a shaft 28 of a drive motor arranged coaxially in the bearing tube 2, of which only the rotor 11 is shown.

Between the bearing tube 2 and the shaft 28, two identically designed ball bearings 3, 6, each with an inner ring 4, 7 and outer ring 5, 8, are arranged, one of which serves as a fixed bearing, the other as a floating bearing. Axially between the two ball bearings 3, 6 is the compression spring 9, which exerts a spring force to eliminate the bearing play against the two outer rings 5, 8.

Different tolerance zones are formed by different tolerance zones on the inner wall surface of the bearing tube 2 in the area of the two ball bearings 3, 6. In a preferred embodiment, the fits of the two bearings are carried out as follows through different tolerance zones of the diameters:

Diameter of the shaft = 4.002 - 4.005 mm

Diameter of the inner rings 5, 7 = 3.995 - 4.000 mm Diameter of the outer rings 5, 8 = 10.995 - 11, 000 mm

Diameter bearing tube ball bearing 6 (fixed bearing) = 10.983 - 10.993 mm

Diameter bearing tube ball bearing 3 (floating bearing) = 11, 000 - 11, 011 mm

Diameter of the bearing tube in the area of the compression spring 9 = 11, 000 - 11, 04 mm

The geometric sizes are adjusted accordingly for larger or smaller versions.

The ball bearing 6 is designed as a fixed bearing, the ball bearing 3 as a floating bearing, and the arrangement can also be reversed. The inner ring 7 is fastened to the shaft 28, the outer ring 8 is fixed to a continuous section of the bearing tube 2 with no press fit. To the Bearing tube 2 is provided on the inner wall surface no contact shoulder or any other geometric paragraph. The bearing tube 2 extends continuously without a step in the axial direction, so that all components can be assembled from a single axial side. The second, identically designed ball bearing 3 is a floating bearing and also fixed to the shaft 28 with its inner ring 4. The outer ring 5 is also axially displaceable with a clearance fit on a continuous, shoulder-free section of the bearing tube 2. In the axial area of the compression spring 9 between the two ball bearings 3, 6, the third axial fit zone is provided, which in the embodiment shown corresponds to that of the fit zone of the ball bearing 3 determining the floating bearing, so that only two different fit zones are provided. The third fit zone in the area of the compression spring 9 is, however, variably adaptable and can differ from the two fit zones of the ball bearings 3, 6.

Furthermore, in the exemplary embodiment shown, the axial fit length L1 of the first fit zone of the ball bearing 6 determining the fixed bearing and the second fit zone of the ball bearing 3 determining the floating bearing are determined as 0.4 of the inner diameter of the bearing tube 2. Both fit zones are immediately adjacent to the axial edge sections of the bearing tube 2 adjacent.

At the upper axial end portion of the bearing tube 2, in the exemplary embodiment according to FIG. 1, an integral collar 25 is also formed in the bearing tube 2, which defines the receiving space 87 for inserting the fan wheel 17.

The exemplary embodiment according to FIG. 2 has the same features as that from FIG. 1, but differs in that the collar 25 is not provided on the bearing tube 2 but as a separate component. In the embodiment shown, the collar 25 is formed by a flow divider. det, which is described in more detail for Figure 3.

FIG. 3 shows a radial fan 100 with the bearing arrangement 1 from FIG. 1 in a sectional view. The radial fan 100 comprises an electric motor 92 designed as a can motor with the rotor 11 and a stator 32. The magnets of the rotor 11 are fastened to the shaft 28, which extends axially through the radial fan 100 along the axis of rotation. The fan wheel 17, which is designed as a radial fan wheel, is fastened to the shaft 28 and, during operation, axially sucks air in via its impeller blades via the inlet 69 and blows it out at the outlet 44 via the pressure connection 33. The radial fan 100 also includes this

Fan housing, which is formed by the outer part 40, the inner part 50 and the housing cover 19 in which the motor 52 is received. The printed circuit board 110 with the electronic components fixed thereon for regulating the radial fan 100 and on the housing cover 19 is fastened axially between the inner part 50 and the motor 52. The inner part 50 on the one hand forms a free space for the electronic components on a side facing the motor 52, and on the other hand it determines, together with the outer part, the spiral pressure space D on the opposite axial side of the radial fan 100 facing the outer part 40. The inner part 50 extends behind radially outside to between the outer part 40 and the housing cover 19 and is over the outer part 40 and

Housing cover 19 fixed. Seals 25 are provided in order to seal the two axial regions separated by the inner part 50. The electrical components are arranged in the free space adjacent to the pressure chamber D and thus facing the flow, whereby heat is released to the inner part 50 and thus cooling.

Radially adjacent to the fan wheel 17 is the annular one

Arranged fan flow 17 surrounding flow divider 18, which also forms the bearing tube 2. The flow divider 18 forms with the outer part 40 Ċ a diffuser in the pressure room D.

Claims

1. Bearing arrangement (1) designed as a fixed-loose bearing for a rotor (11) of a fan, with a bearing tube (2), a compression spring (9), a shaft (28) arranged coaxially to the bearing tube and two between the bearing tube (2) and the shaft (28) arranged, identically formed ball bearings (3, 6) each with inner ring (4, 7) and outer ring (5, 8), wherein several different fit zones are formed axially along the bearing tube (2), one in first axial fit zone of one of the ball bearings (3, 6) fixed as a fixed bearing with its inner ring on the shaft (28) and its outer ring fixed to a continuous, shoulder-free section of the bearing tube (2) with a press fit and in a second axial fit zone another the ball bearing (3, 6) is attached as a floating bearing with its inner ring to the shaft (28) and its outer ring is axially displaceable with a clearance fit on a continuous, paragraph-free section of the bearing tube (2), wherein the compression spring (9) is arranged in a third axial fit zone and a tension against the outer rings (5, 8) of the ball bearings (3, 6) is positioned and configured axially between the ball bearings (3, 6) and is designed to play a bearing Eliminate floating bearing

2. Bearing arrangement according to claim 1, characterized in that the different fit zones are formed by tolerance zones of an inner diameter of the bearing tube (2).

3. Bearing arrangement according to claim 1 or 2, characterized in that the third axial fit zone corresponds to the second axial fit zone.

4. Bearing arrangement according to one of the preceding claims, characterized in that an axial fit length L1 of the first pas is determined that 0.35 * L1 <D <0.5 * L1, where D is an inner diameter of the bearing tube (2).

5. Bearing arrangement according to one of the preceding claims, characterized in that an axial fit length L2 of the second fit zone of the floating bearing is determined, that is 0.35 * L2 <D <0.5 * L2, where D is a bearing tube inner diameter of the bearing tube ( 2) is.

6. Bearing arrangement according to one of the preceding claims, characterized in that the first and / or second fit zone each adjoin adjacent axial edge sections of the bearing tube (2).

7. Bearing arrangement according to one of the preceding claims, characterized in that a base material of the outer rings (5, 8) of the ball bearings (3, 6) is the same as a material of the bearing tube (2).

8. Bearing arrangement according to one of the preceding claims, characterized in that the outer rings (5, 8) of the ball bearings (3, 6) and the bearing tube (2) are formed from soft magnetic steel.

9. Bearing arrangement according to one of the preceding claims, characterized in that at one axial end portion of the bearing tube res (2) in one piece in the bearing tube (2) integrated a collar (25) is formed, which has a receiving space (87) for inserting a

Fan wheel (17).

10. Bearing arrangement according to one of the preceding claims 1-8, characterized in that a separate collar (25) is arranged on an axial end portion of the storage tube (2), which has a receiving space (87) for inserting a fan wheel (17th ) having.

11. Fan (100) with a bearing arrangement (1) according to one of the preceding claims.