GB1604990A - Bearing condition monitoring - Google Patents

Description

(54) BEARING CONDITION MONITORING (71) We, RANSOME HOFFMANN POL LARD LIMITED, a British Company of New Street, Chelmsford, Essex CMI lPU, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to rolling element bearings and more particularly to bearing condition monitoring.

According to the present invention there is provided a rolling element bearing provided with in-situ temperature monitoring means on a closure means or shield or stationary race of the bearing said monitoring means serving to provide an indication of the temperature prevailing within the region of the rolling elements to signify the operating condition of the bearing. The monitoring means can provide a reliable prediction of bearing failure by sensing excessive temperature.

The failure of a rolling element bearing can have serious consequences in many applications. Bearing failure may be caused by the ingress of dirt or foreign material, by excessive loading or by lubrication problems.

Usually bearing failure can occur quite rapidly and the detection of the faulty conditions giving rise to the failure is not always possible. A bearing made in accordance with the invention is especially useful in applications where it would not be feasible or desirable to halt the operation of the associated machinery or equipment to check the condition of a conventional bearing.

Examples of such applications include mass and process production plant, rolling mills and conveyors, pumps, motors and generators, textile machinery and automobile and aircraft engine and control mechanisms. The detection of excessive temperature by the monitoring means can indicate the onset of a faulty condition and enables the associated machinery to be temporarily halted to enable repair or replacement of the bearing in question before more serious damage can occur.

The invention may be understood more readily, and various other features of the invention may become apparent, from consideration of the following description.

Embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawing in which Figures 1 and 2 are each sectional side views of part of a rolling-element bearing constructed in accordance with the invention.

As depicted in Figure 1 of the drawing, a rolling element bearing is composed of inner and outer races 10, 11 with a plurality of rolling elements, here in the form of balls 12, retained by a cage 13 between the races 10, 11. Closure means in the form of a shield 14 extends between the races 10, 11 to seal off the interior of the bearing. In accordance with the invention, temperature monitoring means in the form of a sensor or transducer 15 is encapsulated in a flexible synthetic plastics material moulded to form a grommet 17 which snaps directly into a bore 16 in the shield 14. The transducer 15 itself may take the form of a thermistor and during operation of the bearing the change in the resistance of the thermistor, resulting from a change in temperature, may be used as a parameter to provide a control or indication signal representing the condition of the bearing. The sensor 15 may be used with control apparatus which thence indirectly senses any excessive rise in temperature indicating a faulty condition. A range of thermistors suitable for operating over a wide ambient temperature range enable the condition monitoring means to be specifically adapted to the predetermined operating environment of the bearing.

In Figure 2, like reference numerals de note like parts to Figure 2. In the bearing depicted in Figure 2, the exterior of the shield 14 supports condition monitoring means in the form of a thermochromic device 18 composed of a layer of material of a composition such as to change colour in dependence on a change in temperature. The device 18 may change colour progressively to provide a direct visual indication of temperature. Alternatively, indicia forming a scale may be provided on the exterior of the shield 14 and the device 18 may reflect ambient light from different regions thereof adjacent the scale to again register temperature. The device 18 may take the form of encapsulated liquid crystals.

A bearing made in according with the invention may have a single temperature monitoring means, such as the transducer or sensing device as described, or a plurality of individual temperature monitoring means mounted at different locations.

In general, the or each condition monitoring means can be fabricated quite cheaply and used without extensive modification of standard bearings. A reliable indication of the operating condition of a bearing can be provided by adopting monitoring means as described and bearing failure and expensive resultant damage can be prevented.

In the case where remote or automatic monitoring is desirable, the condition monitoring means of all or some of the bearings may be connected to apparatus designed to perform some control function. Such control apparatus may provide a fail safe control whereby machinery or equipment is automatically halted should the apparatus detect a fault signal derived from the condition monitoring means of any one of the bearings.

Wherein a large number of bearings are used, say in a conveyor, the control apparatus may be adapted to automatically scan the temperature monitoring means of the bearings in succession. Again the detection of a single fault condition may directly initiate the halting of the associated machinery.

WHAT WE CLAIM IS: 1. A rolling element bearing provided with in-situ temperature monitoring means on a closure means or shield or stationary race of the bearing, the operating condition of the bearing said monitoring means serving to provide an indication of the temperature prevailing within the region of the rolling elements to signify the operating condition of the bearing.

2. A bearing according to claim 1, wherein the monitoring means provides a direct visual indication of temperature.

3. A rolling element bearing substantially as described with reference to, and as illustrated in, Figures 1 or 2 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. note like parts to Figure 2. In the bearing depicted in Figure 2, the exterior of the shield 14 supports condition monitoring means in the form of a thermochromic device 18 composed of a layer of material of a composition such as to change colour in dependence on a change in temperature. The device 18 may change colour progressively to provide a direct visual indication of temperature. Alternatively, indicia forming a scale may be provided on the exterior of the shield 14 and the device 18 may reflect ambient light from different regions thereof adjacent the scale to again register temperature. The device 18 may take the form of encapsulated liquid crystals. A bearing made in according with the invention may have a single temperature monitoring means, such as the transducer or sensing device as described, or a plurality of individual temperature monitoring means mounted at different locations. In general, the or each condition monitoring means can be fabricated quite cheaply and used without extensive modification of standard bearings. A reliable indication of the operating condition of a bearing can be provided by adopting monitoring means as described and bearing failure and expensive resultant damage can be prevented. In the case where remote or automatic monitoring is desirable, the condition monitoring means of all or some of the bearings may be connected to apparatus designed to perform some control function. Such control apparatus may provide a fail safe control whereby machinery or equipment is automatically halted should the apparatus detect a fault signal derived from the condition monitoring means of any one of the bearings. Wherein a large number of bearings are used, say in a conveyor, the control apparatus may be adapted to automatically scan the temperature monitoring means of the bearings in succession. Again the detection of a single fault condition may directly initiate the halting of the associated machinery. WHAT WE CLAIM IS:

1. A rolling element bearing provided with in-situ temperature monitoring means on a closure means or shield or stationary race of the bearing, the operating condition of the bearing said monitoring means serving to provide an indication of the temperature prevailing within the region of the rolling elements to signify the operating condition of the bearing.

2. A bearing according to claim 1, wherein the monitoring means provides a direct visual indication of temperature.

3. A rolling element bearing substantially as described with reference to, and as illustrated in, Figures 1 or 2 of the accompanying drawings.