DE102013209889A1 - Method and device for relubrication of a grease-lubricated roller bearing - Google Patents

Abstract

A method for relubricating a grease-lubricated roller bearing (5, 6) of a system (1) having a drive unit (2) has the following features: - at least one operating parameter of the roller bearing (5, 6) is recorded, - at least one operating parameter of the drive unit (2 ) is recorded, - on the basis of the different operating parameters relating to both inside and outside the rolling bearing (5, 6), aging of the grease contained in the rolling bearing (5, 6) is determined and a signal for relubrication of the rolling bearing (5, 6) generated.

Description

Field of the invention

The invention relates to a method for relubrication of a grease-lubricated bearing and a device suitable for carrying out such a method.

Background of the invention

From the WO 2011/025430 A1 For example, a method and system for determining and executing correct automatic relubrication for a number of bearings is known. In particular, the relubrication system should be suitable for grease-lubricated bearings. In order to determine data for automatic relubrication, bearing load, bearing temperature and bearing speed are recorded and taken into account in a procedure for the determination of relubrication parameters.

Various devices and methods for rolling bearing lubrication, which also detect storage temperatures are, for example, from US 5,060,760 A. , from the US 2004/0197040 A1 , as well as from the DE 199 47 458 A1 known. In the latter two cases, vibrations or noises are measured in addition to temperatures.

The DE 10 2009 036 228 B4 discloses a method for load-oriented lubrication of tribological systems in which geometric conditions such as shape, mounting position and dimensions of active surfaces of individual components of such systems are taken into account. Taking these influences into account, expectancy values for the wear state of a lubricant that depend on the operating time are determined.

From the EP 1 250 550 B1 For example, there is known a method of determining the condition of the grease in a bearing using a model in which a relationship is established between the type of grease and the type of bearing. Furthermore, the bearing temperature, the speed of the bearing and the load on the bearing are taken into account in the model.

The EP 0 854 314 B1 discloses a method for supplying a rolling bearing with a lubricant which is supplied in solid, pasty or liquid form. The rolling bearing is, for example, a bearing of a godet in a textile machine. Within a textile machine, various bearings can be supplied intermittently with lubricant, depending on recorded operating data.

Another lubricant distribution system is from the EP 2 101 102 A2 known. This lubricant distribution system, which is intended for the lubrication of bearings or joints in machines, has a pressure monitor with at least two pressure measuring cells. The pressure monitor is thus able to detect pressures in various supply lines of the lubricant distribution system.

Object of the invention

The invention has for its object to improve the relubrication of grease-lubricated bearings the relation between the cost of obtaining relevant information during storage operation on the one hand and the match of Nachschmierparametern with the actual requirements on the other hand over the cited prior art.

Description of the invention

This object is achieved by a method for relubrication of a grease-lubricated roller bearing with the features of claim 1 and by a relubrication device with the features of claim 7. In the following in connection with the device for relubrication of a grease-lubricated rolling bearing explained embodiments and advantages of the invention apply mutatis mutandis also for the relubrication process and vice versa.

The grease-lubricated roller bearing is part of a system which also has a drive unit. The drive unit may be, for example, an electric motor, an internal combustion engine, or a drive by wind or water power. In all cases, the drive is a locally separate from the rolling bearing component of the system. As part of the process for relubrication of the bearing, at least one operating parameter of the rolling bearing, as well as at least one operating parameter of the drive unit is detected. On the basis of these different internal or external storage operating parameters, an aging state of the grease contained in the rolling bearing is concluded and, as required, a signal for relubrication of the rolling bearing is generated.

The invention is based on the consideration that with relubrication of highly loaded, in particular high-revolving roller bearings with grease, exact compliance with regreasing parameters is required. Both a lack of lubrication and an over-lubrication pose the risk of hot running at high speed ranges in grease-lubricated bearings. Under high speed ranges in this context speed characteristics n · dm (rotational speed n · average bearing diameter dm) of more than 1.0 million mm × min ^-1 , in particular more than 1.8 million mm × min ^-1 , understood. In order to determine the parameters of relubrication as precisely as possible, the prior art records and evaluates numerous measured values on the rolling bearing.

However, the invention proposes a fundamentally different way of doing this, in that, in addition to an operating parameter detected on the roller bearing, a further operating parameter is used to determine regreasing parameters, in particular the determination of a regreasing time and the amount of lubricating grease to be supplied, which component is located at a component spaced from the roller bearing , namely drive component, the entire, the rolling bearing comprehensive system is detected.

As an operating parameter of the rolling bearing, the rolling bearing temperature is preferably detected. In addition to the rolling bearing temperature, for example, a vibration detected on the rolling bearing can also be used as the operating parameter of the rolling bearing. If an electric motor is provided as the drive unit, its motor current is preferably detected as the operating parameter. In the case of an internal combustion engine drive, for example, the fuel consumption can be detected as operating parameters of the drive unit. With any drive, there is the possibility of detecting a torque of the drive unit as an operating parameter. An operating parameter detected in or directly on the roller bearing is generally referred to as a bearing-internal operating parameter; an operating parameter detected at the drive unit is generally referred to as out-of-process operating parameter. Sensors for detecting the various operating parameters are called corresponding to internal or external storage sensors. Of particular advantage is the fact that in many types of systems, a drive unit is already equipped with a sensor, that is, at least one external sensor, which is additionally useful for determining parameters of relubrication.

Lagerextern obtained data, in particular motor current data of an electric drive unit, can be used to set the lubrication of the rolling bearing bearing target data, such as a maximum storage temperature set. Based on such target data, a relubrication system of an industrial plant operating according to the method of the invention can, for example, automatically ensure that, with a temperature increase of 0.2 to 10% (based on the absolute temperature in Kelvin), above the setpoint temperature of the bearing (measured on the outer ring of the bearing) Rolling bearing) automatically relubricated with the correctly calculated amount of lubricant. The setpoint temperature of the rolling bearing can be dependent not only on the motor current of the drive unit, but also, for example, on a rotational speed measured either on the rolling bearing or on the drive unit and on an ambient temperature measured outside the rolling bearing. The relubrication amount is, with a dependency on internal or external storage operating parameters may be given, preferably 0.1-10% of Erstbefettungsmenge.

In a preferred embodiment of the relubricating process, the various operating parameters recorded enter into a simulation of the aging process of the lubricating grease, which comprises both chemical aging of the lubricating grease and physical aging processes. The term "chemical aging" encompasses, in particular, the oxidation of the lubricating grease, in installations in which combustion processes take place, in particular in the case of an internal combustion engine drive, possibly also a nitration and / or sulphation of the lubricating grease. Physical changes of the grease in the course of the operation of the rolling bearing, that is, physical, aging and / or stress-related state changes, in particular in the form of an increasing content of foreign substances, especially abrasive particles and water, play a role. Also caused by mechanical influences shear or separation of the lubricant is in this sense a physical aging process.

According to an advantageous development of the relubricating process, on the one hand the chemical aging processes on the one hand and the physical aging processes on the other hand are not balanced in the simulation of the aging of the lubricating grease. Furthermore, there is the possibility that at least one of the states of the lubricating grease, that is to say the chemical and / or physical state of aging, does not enter into the determination of the overall aging state of the lubricating grease in a linear manner.

The grease-lubricated bearing is, for example, a ball bearing, in particular a single or multi-row angular contact ball bearing. Likewise, the relubrication is applicable to any other types of rolling bearings, such as cylindrical roller bearings, spherical roller bearings or tapered roller bearings. Regardless of the type of rolling elements, the post-lubricated bearing can be provided for radial bearing or predominantly for receiving radial forces. Likewise, however, the relubrication method is also applicable to thrust bearings or bearings, which mainly absorb axial forces.

In a special way, the advantages of the relubricating process in high-speed roller bearings, for example spindle bearings, come into play. These are typically angular contact ball bearings, ie radial-axial bearings. In all cases, depending on the speed of the stored, in particular driven by electric motor components and dependent on the drive power steady-state temperatures can be determined during the course of the grease distribution and used for later Nachschmiervorgänge.

The speed factors in spindle bearings, like those used in machine tools, can be up to 3,000,000 mm · min ^-1 when using the Nachschmierverfahrens invention. In contrast to conventional regreasing processes, the invention serves not only to extend the service life of the grease, but also to increase the speed characteristic. The achieved here speed characteristics are in orders of magnitude, as they are otherwise at best be realized with oil / air lubrication. The high equipment cost of oil / air lubrication, such as the provision of filtered and dried air, eliminates the principle.

At the same time, basic advantages of grease lubrication compared with oil lubrication, such as the sealing effect of the grease, are used. In addition, the grease lubrication at low speeds, which may also occur in systems with high possible speeds, for example roughing in the case of a machine tool, the advantage of better lubrication in mixed friction range, since the probability of metal / metal contact by the due contained in the grease thickener more stable lubricant film is reduced. Furthermore, in the case of grease lubrication, as provided in the present case, the advantage over oil lubrication is that there is less dependence on the mounting position of the mounted components, for example the vertical or horizontal arrangement of a shaft. The relubrication method according to the invention is suitable for systems with vertical shaft, for systems with horizontal shaft, for systems with indefinite mounting position, as well as for pivoting position of a shaft.

An embodiment of the invention will be explained in more detail with reference to a drawing. Here is a simplified representation:

Short description of the drawing

1 A multiple grease-lubricated bearings, namely spindle bearings, having industrial plant.

Detailed description of the drawing

A total with the reference numerals 1 characterized industrial plant, also referred to as plant for short, comprises a drive unit only hinted at 2 , namely an electric motor drive, which is a spindle 3 a machine, of which a detail of a housing 4 is visible, drives. The housing 4 is not necessarily the case of the whole machine. Rather, it can also be a housing of a machine component, for example a spindle housing. At the plant 1 it is a machine tool. The spindle 3 is in the case 4 with the help of two rolling bearings 5 . 6 , Angular contact ball bearings, stored. The common axis of rotation of the drive unit 2 , that is, the electric motor, and the rolling bearing 5 . 6 is denoted by R.

At the rolling bearings 5 . 6 These are grease-lubricated high precision bearings. For relubrication of rolling bearings 5 . 6 are flexible cables 7 . 8th provided, which to a Fettnachschmiergerät 9 are connected. The wires 7 . 8th open into the housing 4 , Through in the housing 4 extending and each in the outer ring of the bearings 5 . 6 existing holes through the grease passes directly to the rolling elements of the two bearings 5 . 6 , A room, which both rolling bearings 5 . 6 may be sealed. As a lubricant for initial lubrication and relubrication of rolling bearings 5 . 6 is a high-speed grease suitable. These may be, for example, a lithium complex soap fat, a barium complex soap fat, a calcium complex soap fat or a fat with polyurea thickener.

The grease remover 9 is technically linked to a control and monitoring unit 10 , to which also two test leads 11 . 12 are connected, via which each measured on the outer ring bearing temperatures of the bearings 5 . 6 be recorded. About another measuring line 13 connected to the control and monitoring unit 10 is connected, speed signals are transmitted from one next to the rolling bearing 6 arranged speed sensor 14 supplied, which the rotation and / or angular position of the spindle 3 in the case 4 measures. To the control and monitoring unit 10 are also measured motor current data MD of the drive unit 2 and stored bearing data LD, which are the two not necessarily similar rolling bearings 5 . 6 relate to. The representation after 1 is to be understood symbolically; the storage of the storage data LD could, for example, also in the control and monitoring unit 10 be integrated. The motor current data MD is It deals with data required for the operation of the drive unit 2 be available anyway and thus without additional hardware overhead by the control and monitoring unit 10 and the grease remover 9 are usable. A motor current sensor 15 is part of the drive unit 2 ,

Central function of the control and monitoring unit 10 is the need-based relubrication of rolling bearings 5 . 6 with fat. It is assumed that the rolling bearings 5 . 6 maximum with the amount of grease usual for sealed bearings are first greased. For the determination of parameters of a time- and quantity-appropriate re-greasing, on the one hand, there are storage-internal operating parameters of the plant 1 detected. In the present case, these are the bearing temperatures of the rolling bearings 5 . 6 as well as directly on the rolling bearing 6 by means of the speed sensor 14 , that is, with an internal sensor, measured spindle speed 3 , Optionally processes the control and monitoring unit 10 Also signals of a special, not shown, the lubricant sensor, which on one of the bearings 5 . 6 or at each of the rolling bearings 5 . 6 is mounted as an internal sensor and, for example, according to the DE 10 2006 015 111 A1 can be constructed. Such a sensor is provided in addition to the temperature measurement for measuring the water content and the solids content in the lubricant.

On the other hand, the determination of relubrication parameters also includes out-of-process operating parameters. In the present case, this is the measured motor current of the electric drive unit 2 , Through the utilization of both an internal storage as well as an external storage sensor data obtained is a very good overall condition created to detect a drifting of operating parameters from the intended area early and reliable.

In addition, you can also get more information outside the bearings 5 . 6 for example, the presence and composition of one through the plant 1 conveyed through medium, which influences the rolling bearings 5 . 6 exercise by the control and monitoring unit 10 can be used to calculate relubrication times as well as correct amounts of added grease. Grease lubrication itself occurs by applying pressure to the grease used as lubricant only during a delivery cycle. Otherwise, the grease remains during the normal operation of the system 1 depressurized or largely depressurised in the grease remover 9 and in the pipes 7 . 8th , In this way, it is reliably prevented that the spindle bearing grease used as lubricant, which is suitable for high rotational speeds, is separated under permanent pressurization. The bearing of the spindle 3 through the rolling bearings 5 . 6 is designed for speed characteristics up to 3 million mm · min ^-1 , for example for a speed characteristic of 2.2 million mm · min ^-1 .

LIST OF REFERENCE NUMBERS

1

 investment

2

 drive unit

3

 spindle

4

 casing

5

 roller bearing

6

 roller bearing

7

 management

8th

 management

9

 Fettnachschmiergerät

10

 Control and monitoring unit

11

 Measurement line

12

 Measurement line

13

 Measurement line

14

 Speed sensor

15

 Motor current sensor

LD

 inventory data

MD

 Motor current data

R

 axis of rotation

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• WO 2011/025430 A1 [0002]
• US5060760A [0003]
• US 2004/0197040 A1 [0003]
• DE 19947458 A1 [0003]
• DE 102009036228 B4 [0004]
• EP 1250550 B1 [0005]
• EP 0854314 B1 [0006]
• EP 2101102 A2 [0007]
• DE 102006015111 A1 [0026]

Claims (10)

Method for relubricating a grease-lubricated rolling bearing ( 5 . 6 ) one a drive unit ( 2 ) ( 1 ), having the following characteristics: - at least one operating parameter of the rolling bearing ( 5 . 6 ) is detected, - at least one operating parameter of the drive unit ( 2 ) is detected, - based on the different states inside and outside the rolling bearing ( 5 . 6 ) operating parameter is an aging of the rolling bearing ( 5 . 6 ) and a signal for relubrication of the rolling bearing ( 5 . 6 ) generated. Method according to Claim 1, characterized in that the operating parameters of the rolling bearing ( 5 . 6 ) a rolling bearing temperature is detected. Method according to claim 1 or 2, characterized in that as drive unit ( 2 ) an electric motor is provided and as an operating parameter of the drive unit ( 2 ) a motor current is detected. Method according to one of claims 1 to 3, characterized in that the various detected operating parameters are included in a simulation of the aging process of the grease, which includes both a chemical aging of the grease and its physical changes. A method according to claim 4, characterized in that the chemical aging processes on the one hand and the physical aging processes, on the other hand, are weighted unequally in the simulation of the aging of the lubricating grease. A method according to claim 4 or 5, characterized in that at least one of the states of the grease, which includes chemical and physical aging states, is not linearly included in the determination of the aging state of the grease. Device for relubricating a grease-lubricated, in a system with an electric drive unit ( 2 ) built-in rolling bearing ( 5 . 6 ), having the following features: - the rolling bearing ( 5 . 6 ) has a sensor ( 14 ) for determining a first, internal, internal operating parameter, - the drive unit ( 2 ) has a sensor ( 15 ) for determining a second, out-of-process parameter, - a control and monitoring unit ( 10 ) is with both sensors ( 14 . 15 ) and to simulate an aging process of the rolling bearing grease ( 5 . 6 ) as well as to trigger a relubrication process. Apparatus according to claim 7, characterized in that a sensor ( 14 ) is provided for speed detection. Apparatus according to claim 7 or 8, characterized in that the rolling bearing ( 5 . 6 ) is designed as a ball bearing, in particular angular contact ball bearings. Device according to one of claims 7 to 9, characterized in that the rolling bearing ( 5 . 6 ) is designed as a spindle bearing, in particular a machine tool.

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