DE102020130526A1 - Roller bearing arrangement, method for producing a roller bearing arrangement, electric machine and electrically operable drive train of a motor vehicle - Google Patents

Abstract

The invention relates to a rolling bearing arrangement (1), comprising a rolling bearing (2) with an inner ring (3), an outer ring (4), rolling bodies (5) and a cage (6), the inner ring (3) having an inner ring raceway (7) and the outer ring (4) has an outer ring raceway (8), the rolling elements (5) being mounted in the cage (6) so as to roll between the inner ring (3) and the outer ring (4) at a distance from one another, the cage (6) being snap cage (9) for the rolling elements (5) designed as bearing balls (10), and has a snap cage ring (11) and a plurality of snap cage pockets (12) arranged on the snap cage ring (11) for receiving the bearing balls (10).
According to the invention, the snap cage (9) is designed in several parts, with at least a first snap cage segment (13) and a second snap cage segment (14) which are accommodated in the roller bearing (2) so that they can move relative to one another.

Description

field of invention

The invention relates to a roller bearing arrangement, comprising a roller bearing with an inner ring, an outer ring, roller bodies and a cage, the inner ring having an inner ring raceway and the outer ring having an outer ring raceway, the roller bodies being mounted in a rolling manner between the inner ring and the outer ring in the cage and spaced apart from one another , wherein the cage is designed as a snap cage for the rolling elements designed as bearing balls, and has a snap cage ring and a plurality of snap cage pockets arranged on the snap cage ring for receiving the bearing balls. The invention also relates to a method for producing a roller bearing arrangement, an electric machine and an electrically operable drive train of a motor vehicle.

Background of the Invention

In general, snap cages for roller bearings, in particular for ball bearings, are known in various designs. The most common forms have a continuous solid walled snap cage ring on one side, while shell-like slotted or recessed snap cage pockets are arranged on the other side so that the snap cage pockets are resilient and the rolling elements can snap into the snap cage pockets. For example, in the DE 10 2015 214 850 A1 discloses such a solid plastic cage.

In particular in high-speed applications, such as in electric motors within a hybrid or all-electric drive train of a motor vehicle, such snap cages are exposed to high loads due to the speed.

object of the invention

It is therefore the object of the invention to provide a roller bearing arrangement which allows long-lasting and reliable operation of the roller bearing arrangement even at high speeds. It is also the object to provide a method for producing such a roller bearing arrangement. Furthermore, it is the object of the invention to realize an electrical machine with an improved roller bearing arrangement. Finally, it is also the object of the invention to provide an electrically operable drive train of a motor vehicle with an improved roller bearing arrangement.

Description of the invention

This object is achieved by a roller bearing arrangement, a roller bearing with an inner ring, an outer ring, roller bodies and a cage, the inner ring having an inner ring raceway and the outer ring having an outer ring raceway, the roller bodies between the inner ring and the outer ring being mounted in the cage in a rolling manner and spaced apart from one another , wherein the cage is designed as a snap cage for the rolling elements designed as bearing balls, and has a snap cage ring and a plurality of snap cage pockets arranged on the snap cage ring for receiving the bearing balls, the snap cage being designed in multiple parts, with at least a first snap cage segment and a second snap cage segment are mutually movably received in the roller bearing.

The at least two-part design ensures that vibration and stress peaks at high speeds of rotation of the roller bearing and snap cage can be largely avoided by allowing the snap cage segments to move constructively within the snap cage. In particular, a material failure of the snap cage that occurs at high speeds can be prevented in this way.

First, the individual elements of the claimed subject matter of the invention are explained in the order in which they are mentioned in the set of claims, and particularly preferred configurations of the subject matter of the invention are described below.

Rolling bearings can be used in particular to enable rotary movements with the lowest possible friction losses. Rolling bearings can be used in particular to fix and/or mount axles and shafts, depending on the design, absorbing radial and/or axial forces and at the same time enabling the rotation of the shaft or the components mounted on an axle in this way.

For this purpose, rolling elements are arranged between an inner ring and an outer ring of the roller bearing. Between these three main components, the inner ring, the outer ring and the rolling elements, it is usually mainly rolling friction that occurs within the rolling bearing. Since the rolling elements in the inner and outer ring can preferably roll on hardened steel surfaces with optimized lubrication, the rolling friction of such bearings is relatively low. A roller bearing can have one or more rows.

The inner ring can in particular connect the shaft accommodating the roller bearing to the roller bearing or the roller bodies. In particular, the shaft can be connected to the side of the lateral surface of the inner ring that faces the shaft, with the rolling elements of the roller bearing rolling on the inner ring raceway that is opposite this lateral surface. The inner ring can be made of a metallic and/or ceramic material. In principle, it is conceivable to design the inner ring in one piece or in multiple pieces, in particular in two pieces.

The outer ring can, in particular, connect the bearing arrangement accommodating the roller bearing to the roller bearing or the roller bodies. In particular, the bearing can be connected to the side of the lateral surface of the outer ring facing the bearing, the rolling elements of the roller bearing rolling on the outer ring raceway opposite this lateral surface. The outer ring can be made of a metallic and/or ceramic material. In principle, it is conceivable to design the outer ring in one piece or in multiple pieces, in particular in two pieces.

Depending on the type of rolling bearing, the rolling elements have the shape of a ball or a roller. They roll on the raceways of the roller bearing and have the task of transferring the force acting on a radial roller bearing from the outer ring to the inner ring and vice versa. In an axial roller bearing, the rolling elements transmit the forces acting on the axial roller bearing between the running disks. Roller-shaped rolling elements are also referred to as roller rolling elements and spherical rolling elements as bearing balls.

Roller-shaped rolling bodies can be selected, for example, from the group of symmetrical spherical rollers, asymmetrical spherical rollers, cylindrical rollers, needle rollers and/or tapered rollers. In connection with the invention, it is particularly preferred that the rolling bodies are designed as bearing balls.

The rolling elements are guided in a cage and arranged at a distance from one another, so that, for example, the friction and heat development of the rolling elements is kept as low as possible. Furthermore, the cage keeps the rolling element balls and/or rolling element rollers at a fixed distance from one another during rolling, as a result of which an even load distribution can be achieved. The cage is made of several parts.

The rolling bodies can roll within the rolling bearing, in particular on the inner ring raceway of the inner ring. For this purpose, the surface of the inner ring raceway can advantageously be designed to be correspondingly abrasion-resistant, for example also by means of a corresponding surface treatment process and/or by applying a corresponding additional layer of material.

The inner ring raceway can be flat or profiled. A profiled design of the inner ring raceway can be used, for example, to guide the rolling elements on the inner ring raceway. On the other hand, a planar formation of the inner ring raceway can, for example, allow a certain axial displaceability of the rolling elements on the inner ring raceway.

The rolling bodies can roll within the rolling bearing, in particular on the outer ring raceway of the outer ring. For this purpose, the surface of the outer ring raceway can advantageously be designed to be abrasion-resistant, for example by means of a corresponding surface treatment process and/or by applying a corresponding additional layer of material.

The outer ring raceway can be flat or profiled. A profiled design of the outer ring raceway can be used, for example, to guide the rolling elements on the outer ring raceway. On the other hand, a flat shape of the outer ring raceway can, for example, allow a certain axial displaceability of the rolling elements on the outer ring raceway.

The bearing shaft is a rotating machine element that is used to transmit rotary movements and torques. The bearing shaft is rotatably mounted in at least one roller bearing of the roller bearing arrangement. The bearing shaft can, in particular, be configured in the shape of a cylinder. A bearing shaft can, for example, also be selected from the group of solid shafts, hollow shafts, crankshafts and/or cardan shafts. It is particularly preferred that the bearing shaft is a rotor shaft of an electrical machine. The bearing shaft can also be a shaft within a hybrid or fully electrically operated drive train of a motor vehicle. It is particularly preferred that the bearing shaft has speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, very particularly preferably greater than 12,500 rpm.

Electrical machines are used to convert electrical energy into mechanical energy and/or vice versa, and generally include a stationary part referred to as a stator, stand or armature and a part referred to as a rotor or runner and arranged movably relative to the stationary part. The electric machine is in particular for use within a drive train of a hybrid or All-electrically powered motor vehicle provided.

In particular, the electrical machine is dimensioned in such a way that vehicle speeds of more than 50 km/h, preferably more than 80 km/h and in particular more than 100 km/h can be achieved. The electric motor particularly preferably has an output of more than 30 kW, preferably more than 50 kW and in particular more than 70 kW. Furthermore, it is preferred that the electrical machine provides speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, very particularly preferably greater than 12,500 rpm.

A rotor is the spinning (rotating) part of an electrical machine. The rotor comprises a rotor shaft and one or more rotor bodies arranged in a rotationally fixed manner on the rotor shaft. The rotor shaft can be hollow, which on the one hand saves weight and on the other hand allows the supply of lubricant or coolant to the rotor body.

According to a preferred embodiment of the invention, it can be advantageous for the snap cage to have an odd number of snap cage pockets, with the first snap cage segment having an even number of snap cage pockets and the second snap cage segment having an odd number of snap cage pockets. It has been shown that such a division of the snap cage segments causes the snap cage to have a particularly long service life.

Furthermore, it can be advantageous that the first snap cage segment and the second snap cage segment are formed from a plastic, as a result of which the snap cage can be designed to be particularly light and favorable in terms of manufacturing technology.

In a further development of the invention, it can also be preferred that the first snap cage segment and the second snap cage segment can be connected to one another via a connecting means, the connecting means being configured in such a way that the first snap cage segment and the second snap cage segment are arranged in the roller bearing so that they can move relative to one another. As a result, the snap cage segments - for example for transport and assembly - arranged captively together. According to a further advantageous embodiment of the invention, it may be preferable for the connecting means to be designed so that it can be severed after the snap cage has been installed in the roller bearing and/or can be removed from the roller bearing.

Furthermore, it can be advantageous that the roller bearing is provided for rotational speeds of a bearing shaft of more than 10,000 rpm, so that a particularly long service life of the roller bearing or the snap cage can be achieved for this operating range.

1. a) Herstellung eines einteiligen Schnappkäfigs,
2. b) Durchtrennen des Schnappkäfigs, so dass wenigstens ein erstes Schnappkäfigsegment und ein zweites Schnappkäfigsegment gebildet ist,
3. c) Anordnen des ersten Schnappkäfigsegments und des zweiten Schnappkäfigsegments in einer Wälzlageranordnung.

The object of the invention is also achieved by a method for producing a snap cage for use in a roller bearing arrangement, in particular according to one of claims 1 to 6, comprising the following steps:

1. a) manufacture of a one-piece snap cage,
2. b) cutting through the snap cage so that at least a first snap cage segment and a second snap cage segment are formed,
3. c) arranging the first snap cage segment and the second snap cage segment in a roller bearing assembly.

This variant of the method has the advantage that an existing manufacturing process for the snap cage, for example an injection molding process, does not have to be changed. In particular, quite expensive injection molding tools do not have to be adjusted or replaced after this. The production of the snap cage segments then takes place after the production of the one-piece snap cage by severing the snap cage. Any suitable separating method can be used for this purpose, such as cutting, sawing, laser cutting, separating welding or the like. The separation preferably takes place between two snap cage pockets.

1. a) Herstellung eines Schnappkäfigs mit wenigstens einem ersten Schnappkäfigsegment und einem zweiten Schnappkäfigsegment,
2. b) Anordnen des ersten Schnappkäfigsegments und des zweiten Schnappkäfigsegments in einer Wälzlageranordnung.

The object of the invention is also achieved by a method for producing a snap cage for use in a roller bearing arrangement, in particular according to one of claims 1 to 6, comprising the following steps:

1. a) production of a snap cage with at least a first snap cage segment and a second snap cage segment,
2. b) arranging the first snap cage segment and the second snap cage segment in a roller bearing assembly.

The advantage of this variant of the method lies in the fact that the snap cage does not need to be separated.

Furthermore, the object of the invention is achieved by an electrical machine, in particular for use within a hybrid or all-electric drive train of a motor vehicle, with a stator and a stator which is coaxial relative to the stator and rotatably arranged rotor, wherein the rotor is supported by means of two axially spaced roller bearing assemblies according to any one of claims 1 to 6. Thus, a stable bearing of the rotor for high speeds can be provided.

Finally, the object of the invention is also achieved by an electrically operable drive train of a motor vehicle comprising an electric machine, wherein at least one bearing shaft is mounted within the drive train by means of two axially spaced roller bearing arrangements according to one of claims 1 to 6

An electric axle drive train of a motor vehicle can in particular also include an electric machine and a transmission, with the electric machine and the transmission forming a structural unit. Provision can in particular be made for the electric machine and the transmission to be arranged in a common drive train housing. Alternatively, it would of course also be possible for the electrical machine to have a motor housing and the transmission to have a transmission housing, with the structural unit then being effected by fixing the transmission in relation to the electrical machine. This structural unit is sometimes also referred to as the E-axis.

character list

• 1 eine Wälzlageranordnung in einer Querschnittsdarstellung,
• 2 einen Schnappkäfig in einer perspektivischen Ansicht,
• 3 eine Lagerwelle n einer elektrischen Maschine mit zwei voneinander axial beabstandeten Wälzlagern, und
• 4 ein Kraftfahrzeug mit einem hybriden- und vollelektrischen Antriebsstrang in einer Blockschaltansicht.

The invention will be explained in more detail below with reference to drawings without restricting the general inventive idea. The drawings are only schematic in nature and are only intended for understanding the invention. Show it:

• 1 a roller bearing arrangement in a cross-sectional view,
• 2 a snap cage in a perspective view,
• 3 a bearing shaft n of an electrical machine with two roller bearings spaced apart axially, and
• 4 a motor vehicle with a hybrid and fully electric drive train in a block circuit view.

Detailed description of the drawings

The same elements are provided with the same reference numbers. The different features of the various exemplary embodiments can also be freely combined with one another within what is technically feasible.

1 shows a roller bearing arrangement 1 comprising a roller bearing 2 with an inner ring 3, an outer ring 4, rolling bodies 5 and a cage 6. The inner ring 3 has an inner ring raceway 7 and the outer ring 4 has an outer ring raceway 8. The rolling elements 5 are mounted between the inner ring 3 and the outer ring 4 in a rolling manner in the cage 6 at a distance from one another. The cage 6 is designed as a snap cage 9 for the rolling bodies 5 designed as bearing balls 10 .

The snap cage 9 is based on the 2 now explained in more detail below. The snap cage 9 consists of a snap cage ring 11 and a plurality of snap cage pockets 12 arranged on the snap cage ring 11 for receiving the bearing balls 10. The snap cage pockets 12 are arranged equidistantly along the circumference of the snap cage ring 11. The snap cage ring 11 runs in the circumferential direction or direction of rotation of the roller bearing 2 and the snap cage pockets 12 extend out of the snap cage ring 11 in the axial direction. The snap cage pockets 12 are configured in such a way that the bearing balls 10 can be arranged captively and rotatably in them.

How from the 2 It can also be seen that the snap cage 9 is designed in several parts, with a first snap cage segment 13 and a second snap cage segment 14 which are accommodated in the roller bearing 2 such that they can move relative to one another.

The Indian 2 Snap cage 9 shown has an odd number of snap cage pockets 12, with the first snap cage segment 13 having an even number of snap cage pockets 12 and the second snap cage segment 14 having an odd number of snap cage pockets 12. Both the first snap cage segment 13 and the second snap cage segment 14 are molded from an identical plastic. As a result, the roller bearing 2 is particularly suitable for rotational speeds of a bearing shaft 16 of more than 10,000 rpm.

The first snap cage segment 13 and the second snap cage segment 14 can be connected to one another via a connecting means 15, the connecting means 15 being configured such that the first snap cage segment 13 and the second snap cage segment 14 are arranged in the roller bearing 2 such that they can move relative to one another. The connecting means 15 is designed to be severable after the snap cage 9 has been installed in the roller bearing 2 and/or can be removed from the roller bearing 2 . In the exemplary embodiment shown, the connecting means 15 is designed as a clamp which, in particular, movably connects the snap cage segments 13, 14 in a form-fitting manner can. Of course, further configurations of a connecting means 15 are possible.

1. a) Herstellung eines einteiligen Schnappkäfigs 9,
2. b) Durchtrennen des Schnappkäfigs 9, so dass wenigstens ein erstes Schnappkäfigsegment 13 und ein zweites Schnappkäfigsegment 14 gebildet ist,
3. c) Anordnen des ersten Schnappkäfigsegments 13 und des zweiten Schnappkäfigsegments 14 in einer Wälzlageranordnung 1.

To produce a snap cage 9, the following method for producing a snap cage 9 for use in a roller bearing assembly 1, comprising the following steps, can be used:

1. a) Production of a one-piece snap cage 9,
2. b) cutting through the snap cage 9 so that at least a first snap cage segment 13 and a second snap cage segment 14 are formed,
3. c) arranging the first snap cage segment 13 and the second snap cage segment 14 in a roller bearing assembly 1.

1. a) Herstellung eines Schnappkäfigs 9 mit wenigstens einem ersten Schnappkäfigsegment 13 und einem zweiten Schnappkäfigsegment 14,
2. b) Anordnen des ersten Schnappkäfigsegments 13 und des zweiten Schnappkäfigsegments 14 in einer Wälzlageranordnung 1.

Alternatively, the manufacture of a snap cage 9 can include the following steps:

1. a) Production of a snap cage 9 with at least a first snap cage segment 13 and a second snap cage segment 14,
2. b) arranging the first snap cage segment 13 and the second snap cage segment 14 in a roller bearing assembly 1.

3 shows an electric machine 17, in particular for use within a hybrid or all-electric drive train 18 of a motor vehicle 19, as in FIG 4 is shown as an example. The electrical machine comprises a stator 20 and a rotor 21 which is arranged coaxially and rotatably relative to the stator 20 and which is supported by means of two roller bearing assemblies 1 which are spaced apart axially, as can be seen from FIGS 1 until 2 are known.

4 finally shows an electrically operable drive train 18 of a motor vehicle 19 comprising an electric machine 17, wherein at least one bearing shaft 16 is within the drive train 18 by means of two axially spaced roller bearing assemblies 1.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be considered as limiting but as illustrative. The following patent claims are to be understood in such a way that a mentioned feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. If the patent claims and the above description define 'first' and 'second' feature, this designation serves to distinguish between two similar features without establishing a ranking.

Reference List

1

roller bearing arrangement

2

roller bearing

3

inner ring

4

outer ring

5

rolling elements

6

Cage

7

inner ring raceway

8th

outer ring raceway

9

snap cage

10

bearing balls

11

snap cage ring

12

snap cage bags

13

first snap cage segment

14

second snap cage segment

15

lanyard

16

bearing shaft

17

electrical machine

18

powertrain

19

motor vehicle

20

stator

21

rotor

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102015214850 A1 [0002]

Claims (10)

Rolling bearing arrangement (1), comprising a rolling bearing (2) with an inner ring (3), an outer ring (4), rolling bodies (5) and a cage (6), the inner ring (3) having an inner ring raceway (7) and the outer ring (4) has an outer ring raceway (8), the rolling bodies (5) being mounted in rolling fashion between the inner ring (3) and the outer ring (4) in the cage (6) and spaced apart from one another, the cage (6) being a snap cage (9) for the rolling bodies (5) designed as bearing balls (10), and has a snap cage ring (11) and a plurality of snap cage pockets (12) arranged on the snap cage ring (11) for receiving the bearing balls (10), characterized in that the Snap cage (9) is designed in several parts, with at least a first snap cage segment (13) and a second snap cage segment (14) which are accommodated in the roller bearing (2) so that they can move relative to one another. Rolling bearing assembly (1) after claim 1 , characterized in that the snap cage (9) has an odd number of snap cage pockets (12), the first snap cage segment (13) having an even number of snap cage pockets (12) and the second snap cage segment (14) having an odd number of snap cage pockets (12) owns Rolling bearing arrangement (1) according to one of the preceding claims, characterized in that the first snap cage segment (13) and the second snap cage segment (14) are molded from a plastic. Rolling bearing arrangement (1) according to one of the preceding claims, characterized in that the first snap cage segment (13) and the second snap cage segment (14) can be connected to one another via a connecting means (15), the connecting means (15) being configured such that the first Snap cage segment (13) and the second snap cage segment (14) are arranged to be movable in relation to one another in the roller bearing (2). Rolling bearing assembly (1) after claim 4 , characterized in that the connecting means (15) after assembly of the snap cage (9) in the roller bearing (2) is designed to be severable and/or can be removed from the roller bearing (2). Rolling bearing arrangement (1) according to one of the preceding claims, characterized in that the rolling bearing (2) is provided for rotational speeds of a bearing shaft (16) of more than 10,000 rpm. Method for producing a snap cage (9) for use in a rolling bearing arrangement (1), in particular according to one of the preceding claims, comprising the following steps: a) production of a one-piece snap cage (9), b) cutting through the snap cage (9) so that at least a first snap cage segment (13) and a second snap cage segment (14) are formed, c) arranging the first snap cage segment (13) and the second snap cage segment (14) in a roller bearing arrangement (1). Method for producing a snap cage (9) for use in a rolling bearing arrangement (1), in particular according to one of the preceding claims, comprising the following steps: a) Production of a snap cage (9) with at least a first snap cage segment (13) and a second snap cage segment (14), b) arranging the first snap cage segment (13) and the second snap cage segment (14) in a roller bearing arrangement (1). Electrical machine (17), in particular for use within a hybrid or fully electric drive train (18) of a motor vehicle (19), with a stator (20) and a rotor (21) arranged coaxially and rotatably relative to the stator (20), characterized in that that the rotor (21) by means of two axially spaced roller bearing assemblies (1) according to one of Claims 1 until 6 is stored. Electrically operable drive train (18) of a motor vehicle (19) comprising an electric machine (17), wherein at least one bearing shaft (16) within the drive train (18) by means of two axially spaced roller bearing arrangements (1) according to one of Claims 1 until 6 is stored.

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