WO2007087783A1

WO2007087783A1 - Apparatus for monitoring machine elements

Info

Publication number: WO2007087783A1
Application number: PCT/DE2007/000122
Authority: WO
Inventors: Eugen Scherf; Joachim Schleifenbaum
Original assignee: Schaeffler Kg
Priority date: 2006-01-31
Filing date: 2007-01-23
Publication date: 2007-08-09
Also published as: DE102006004253A1

Abstract

The invention relates to an apparatus for monitoring machine elements, especially for bearing elements. Said apparatus comprises at least one sensor device (6) which is arranged on a movable machine element (2), monitors at least one physical property of said movable machine element (2), and outputs a value that is characteristic of said physical property. The inventive apparatus further comprises a transmitter device (11) which is disposed on the movable machine element (2) and transmits the characteristic value to a receiver device (8).

Description

Schaeffler KG Industriestraße 1 - 3, 91074 Herzogenaurach

Name of the invention

Device for monitoring machine elements

description

Field of the invention

The present invention relates to an apparatus and method for monitoring machine elements. The invention will be illustrated with reference to a cam roller drive. It should be noted, however, that the invention can also find application in other machine elements such as rolling bearing units and the like.

For oil drilling, mud pumps are used to transport the flushing fluid. These work according to the axial piston principle. In this case, the piston stroke is generated by a cam disk by rolling a cam roller mounted in a fork on the cam disk. The fork is connected to a linearly guided piston rod.

A high flow rate and a high delivery pressure require high speeds and this results in high forces on the machine elements. These forces can lead to failure of these elements, for example, as a result of vibrations. Of central importance for the function of the pump pe is the undisturbed movement of the cam rollers on the cam disc. Slippage or standstill of the cam roller leads to rapid temperature rise in the contact point and thus to increased wear. In addition, there is a risk of explosion at elevated temperature, since the lubrication of the kinematic elements takes place, inter alia, by oil mist.

The present invention is therefore based on the object to prevent the risk of failure of the pump or generally of the relevant machine element and in particular to monitor the respective affected machine element. From the state of the art, for example, it is known to monitor machine parts with regard to their vibrations. Due to this monitoring, however, no reliable slip or standstill detection of the roller is possible.

The object of the invention is achieved by the subject matter of claims 1 and 14. Advantageous embodiments and further developments are the subject of the dependent claims.

A device according to the invention for monitoring machine elements, in particular for bearing elements, has at least one sensor device which is arranged on a movable machine element and checks at least one physical property of this movable machine element. In addition, the sensor device outputs at least one characteristic value for the physical property. Furthermore, a transmitting device is provided on the movable machine element, which outputs the characteristic value to a receiving device.

The receiving device is preferably not arranged on the movable machine element. In principle, the physical property may be properties such as the rotational speed, the vibration behavior, any torsional behavior or even the temperature of the machine element. Preferably, the physical property of the machine element is the temperature of at least a portion of the machine element. By monitoring the temperature of the machine element, it is possible to detect impermissible temperature increases and to transmit these to a user. This can react accordingly and make a check of the moving machine element or the driving element.

The transmitting device preferably transmits the characteristic value wirelessly. Since the machine element is movable and, in the case of a cam roller, executes both a rotational movement and a linear movement, it makes sense to wirelessly transmit the respective temperature values. In this case, optical connections such as infrared connections, radio links, acoustic connections and the like are conceivable between the transmitting device and the receiving device.

By the device according to the invention, the cam roller can be monitored with respect to their temperature and the rotational movement.

In a further preferred embodiment, the device has an energy generating device for supplying at least the sensor device. Since the cam roller rotates, the required energy can be generated, for example, electrodynamically on the cam roller. However, it would also be possible to provide batteries or similar power supplies on the moving element. In a further preferred embodiment, the energy generating device has at least one inductive element. Particularly advantageous, a plurality of magnets or magnetic elements are provided which generate by induction a voltage or a voltage pulse, which can be used for the operation of the sensor device and preferably also of the transmitting device.

Particularly advantageously, the energy generating device has a plurality of magnets, on which a coil unit is guided past.

In a further advantageous embodiment, the device has a speed detection device. By this speed detection device, the rotational movement of the movable element can be monitored. In this way, a possible slip during the rolling movement or a blockage of the roll can be determined, for example, by a downstream evaluation device. Therefore, it can be checked whether the cam rollers run undisturbed on the cam disc.

Thus, the temperature and the rotational movement of the roller are monitored and evaluated for alarm purposes to avoid, for example, pump stoppages due to wear or explosion hazards as a result of high temperatures on the camshaft.

Since the roller rotates at a speed of up to 14 Hz and thereby displaced linearly (with a stroke of 30 mm at approx. 3 Hz), a radio-based measuring and transmission device is particularly suitable. Radio sensors with a low energy requirement are particularly advantageously selected, wherein advantageously these sensors, as mentioned above, can be supplied with the energy from the turning process itself. Particularly preferably, the energy generating device is at the same time the speed detection device or has such. This means that the speed information is preferably obtained from the voltage curve of the power generation device. Generally speaking, in this embodiment at least some of the components of the power generation device are also used by the speed detection device.

In a further preferred embodiment, the device has an energy storage device. This may be, for example, a capacitor or the like. The reason for the presence of the energy storage device is that in this way, even at a standstill of the movable element at least briefly a transmission of temperature values to the receiving device is possible.

In a further preferred embodiment, the device has a generation device for an identification signal. This identification signal is advantageously output together with the characteristic value such as the temperature value. In this way, different transmitting devices can be distinguished from one another in a receiving device and thus identified. It is also possible by the transmission of an identification signal to distinguish the signals of several temperature sensors from each other.

In a further preferred embodiment, a plurality of temperature sensors is provided, wherein the individual temperature sensors are preferably distributed substantially uniformly in the circumferential direction of the movable machine element. The critical temperature increases occur in particular in the contact areas of the cam roller with the cam disk. Therefore, it is advantageous to arrange the respective temperature sensors as far as possible outside on the cam roller. By arranging a plurality of temperature sensors in the circumferential direction of the cam roller, the temperature at the outer periphery can be determined relatively accurately.

It is possible to output the values of all temperature sensors separately. However, a mean value can be calculated and output from the individual temperature values.

The invention is further directed to a cam roller drive with a device of the type shown above.

The invention is further directed to a bearing and in particular a rolling bearing with a device of the type described above.

Finally, the present invention is directed to a method for checking machine elements, wherein in a first method step the temperature of at least one section of a movable machine element is detected by means of a sensor device arranged on the movable machine element. In a further method step, a value characteristic of this physical property is output to a transmitting device and the value is transmitted wirelessly from the transmitting device to a receiving device. This characteristic value or a characteristic signal may be a digital signal, a voltage value or the like.

Preferably, the speed of the machine element is detected in addition to the temperature of the machine element. Advantageously, at least the sensor device and particularly advantageously also the transmitting device is supplied with electrical energy by the movement of the movable machine element, wherein this energy supply is particularly advantageous inductively.

Further advantages and embodiments of the present invention will become apparent from the accompanying drawings.

Show:

Fig. 1 shows a cam roller drive with an inventive

Contraption;

2 shows a block diagram of a transmission device according to the invention;

3 is a block diagram of a power generating device according to the invention; and

Fig. 4 is a partial perspective view of a device according to the invention.

Fig. 1 shows an inventive device for monitoring machine elements, shown on a cam roller drive.

In this case, a cam roller 2 is driven by a cam disc 1. More specifically, the cam plate 1 causes the cam roller 2 on the one hand counterclockwise rotates (along the arrow P1) and on the other hand is caused by the slope 1a, a lifting movement of a fork 3 in the direction of the arrow P2. On the fork 3, a piston rod 4 is mounted on a pump cylinder (not shown). Due to the cam contour, the fork and thus also the cam roller and the pump cylinder execute a stroke movement.

The cam roller 2 forms the outer ring of a roller bearing. The reference numeral 21 refers to a bearing cage for guiding the rolling elements 22; Reference numeral 23 denotes the inner ring.

As mentioned at the outset, it is desirable to check the temperature of the cam roller 1 2 and, in particular, on the outer circumference thereof, where it comes into contact with the cam surfaces 1 a. For this purpose, a plurality of temperature sensors 6 are arranged on the cam roller. These temperature sensors are connected to a transmitting device 5, for example, individually or in series. The individual temperature sensors 6 detect the temperature of the cam roller 2 in the vicinity of the contact surface with the cam disc 1 and can be arranged directly on the roller side surface of the cam rollers or in suitable blind holes in the side surface. Advantageously, the temperature sensors are arranged close to the outer circumference of the cam rollers.

Since, as noted above, the rotational movement and the lifting movement of the cam roller 2 overlap, wireless transmission of the measuring signals and the electrical supply energy is advantageous. Therefore, the measuring signals are detected by the transmitting device 5, processed, and transmitted in a telegram to a receiver (not shown) outside the moving machine parts. It would also be possible in principle to arrange a multiplicity of transmitting devices directly at the respective temperature sensors 6.

On the other hand, the required energy for the sensor devices and the transmitting device is also generated by an energy generating device 7 on the roller side surface from the rotational movement of the roller. Alternatively, a so-called Wiegand sensor could be used.

In addition, it would also be possible to provide the power supply to the sensor devices 6 and the transmitting device 5 with the aid of batteries, which would also be arranged on the cam roller. Also could be used for energy supply solar cells or the like.

For example, temperature sensors such as NTC, PT 10000 or the like can be used as sensor devices.

FIG. 2 shows a block diagram of a transmission device 5, for example in use according to FIG. This transmitting device 5 has an HF transmitter 11, which transmits the determined temperature values or signals corresponding thereto via a radio link to a receiving device 8.

In addition, the transmitting device 5 has a microcontroller 10 with analog and digital interfaces. The individual sensor devices 6 are connected via these interfaces.

The reference numeral 9 refers to an energy storage, which serves to buffer the supply energy, so even then radio telegrams are sold at least for a limited time when the sensor device 5 is no longer supplied by the power generation device 7 when the roller is stopped.

The transmitting device 5 can be set so that it transmits measured values to the receiving device 8 at respectively predetermined time intervals. In addition, an adjustment is possible in such a way that, if necessary, these intervals are shortened. Preferably, the microcontroller 10 is woken up for a very short period of time in order to detect and process the monitoring or temperature signals. The corresponding values are then preferably transmitted to the receiving device 8 in the context of a telegram together with an identification code by means of the RF transmitter 11. For this purpose, a license-free radio frequency (ISM) is preferably used. From the receiving device, the signals are further forwarded to a (not shown) central measuring and control unit for the operation of the sludge pump.

FIG. 3 shows a block diagram of a power generation unit 7 according to the invention, and FIG. 4 shows a perspective view of the power generation unit 7. This power generation unit 7 has an energy converter 12, a voltage converter 13, a speed converter 14 and a speed comparator 15. The energy converter 12 has (see Fig. 4) one or more coils 16, which are wound on a U-shaped core 17 (see Fig. 4), and a plurality of fixed on a substantially concentric with the cam roller circular path and the fork stationary arranged permanent magnet 18 on.

These permanent magnets 18 are alternately magnetized in the embodiment shown in Fig. 4. Instead of the arrangement shown in Fig. 4, the respective magnets could also be arranged vertically thereto and thus in the form of a magnetic disk.

The coils 16 are mounted on the side surface of the roller so that they move past the respective magnet 18 as the roller rotates with a small air gap. Depending on this relative speed, a more or less high electrical voltage is induced. The voltage converter 13 (see Fig. 3) generates from this AC voltage a nearly constant DC voltage, which is applied to the energy storage 9. The coils 16 and the magnets 18 can be arranged so that an axial and / or a radial air gap field is formed, which ultimately depends on the available space.

From the induced coil voltage, which can originate either from an energy converter 13 or a separate coil, a voltage signal is generated with the aid of the speed converter 14, which provides a measure of the rotational speed. The microcontroller 10 further processes this signal together with the temperature signals. In addition, the speed comparator 15 can generate a binary signal in order to be able to signal the undershooting of a (critical) fixed speed limit and thus also a standstill. This signal is also processed by the microprocessor 10 for the radio transmission and forwarded to the receiving device. The permanent magnets 18 are arranged on a disc 19 and this in turn within an adapter unit of the fork 3, as shown in Fig. 4. The two coils 16 are opposite here two oppositely oriented permanent magnet.

Preferably, a balance mass is located on the caster roller 2 which balances the masses of the bobbins 16 and the bracket 17 on the opposite side of the cam roller 2.

It would be conceivable in this context, other types of speed measurement, such as optical devices in the form of perforated discs, mechanical signalers and the like. The present invention provides an energy self-sufficient monitoring system for the temperature and the rotational speed of a rotating bearing component, in this case in particular the cam roller on a mud pump.

All disclosed in the application documents features are claimed as essential to the invention, provided they are new individually or in combination over the prior art.

LIST OF REFERENCE NUMBERS

1 cam disc

1a slope

2 cam roller

3 fork

4 piston rod

5 transmitting device

6 sensor device

7 power generation facility

8 receiving device

9 energy storage

10 microcontroller

11 RF transmitter

12 energy converters

13 voltage transformers

14 speed converter

15 speed comparator

16 coils

17 U-shaped core

18 permanent magnets

19 disc

21 bearing cage

22 rolling elements

23 inner ring

Claims

Schaeffler KG Industriestraße 1 - 3, 91074 HerzogenaurachPatent claims

1. Device for monitoring machine elements, in particular for bearing elements, with at least one sensor device (6) which is arranged on a movable machine element (2), at least one physical property of this movable machine element (2) checked and one for this physical property outputs characteristic value and a transmitting device (5) arranged on the movable machine element (2) which outputs the characteristic value to a receiving device (8).

2. Apparatus according to claim 1, characterized in that the transmitting device (5) transmits the characteristic value wirelessly.

3. Device according to at least one of the preceding claims, characterized in that the physical property of the machine element is the temperature of at least a portion of the machine element (2).

4. Device according to at least one of the preceding claims, characterized in that the device has an energy generating device (7) for supplying at least the sensor device (6).

5. Device according to claim 3, characterized in that the energy generating device (7) has at least one inductive element (16).

6. Device according to at least one of the preceding claims 3-4, characterized in that the energy generating device (7) has a plurality of magnets

(18).

7. Device according to at least one of the preceding claims, characterized in that the device has a speed detection device (14).

8. Apparatus according to claim 7, characterized in that the energy generating device (7) serves as a speed detection device (14).

9. Device according to at least one of the preceding claims, characterized in that the device has an energy storage device (9).

10. The device according to at least one of the preceding claims, characterized in that the device comprises a generating device for an identification signal.

11.Vorrichtung according to at least one of the preceding claims, characterized in that a plurality of temperature sensors (6) is provided, wherein the individual temperature sensors (6) are preferably distributed substantially uniformly in the circumferential direction of the movable machine element (2).

12. cam roller drive with a device according to at least one of the preceding claims.

13. Bearing with a device according to at least one of the preceding claims.

14. Method for verifying machine elements with the steps

Detecting the temperature of at least a portion of a movable machine element (2) with one on the movable

Machine element (2) arranged sensor device (6).

Output of a characteristic of this physical property value to a transmitting device (5).

Wireless transmission of the characteristic value from the transmitting device (5) to a receiving device (8).

15. The method according to claim 14, characterized in that in addition to the temperature of the machine element (2) and the rotational speed of the machine element (2) is detected.

16. The method according to at least one of the preceding claims 14-15, characterized in that at least the sensor device (6) is supplied with electrical energy by the movement of the movable machine element.