This patent appl ication claims priority from Italian patent application no . 102020000031241 filed on December 17 , 2020 , the entire disclosure of which is incorporated herein by reference . TECHNICAL FIELD

The present invention relates to a seal for a bearing, and a bearing comprising this seal .

BACKGROUND ART

Many bearings are lubricated with grease and equipped with a hermetic seal on the one side and a seal with a single lip on the other side .

The single-lip seal is configured so that grease is expelled during the normal operation of the bearing and, in particular, when the grease is topped up . This means that cleaning the used-up grease expelled from the s ingle-lip seal must be performed periodically . In some circumstances , for example in the case of large plants , such as for example a cable car, with large bearings and/or in plants located high above the ground, such as for example a wind turbine , it is very inconvenient to perform said cleaning operation of used-up and expelled grease and it requires the dismantling of some components . In this case , said operation entails high costs and maintenance times .

DISCLOSURE OF INVENTION

The aim of the present invention is , thus , to provide a seal for a bearing that reduces the drawback of the prior art .

According to the present invention, a seal for a bearing is provided . The seal comprises a tooth configured so it can be inserted into a groove of the bearing, in particular of a first element of the bearing; a first lip configured to be in sliding contact with a second element of the bearing coupled so it can rotate with the first element ; a compartment defined between the tooth and the first lip ; and a chamber coupled to the compartment so as to collect excess grease from the bearing .

Thanks to the chamber, the excess grease is accumulated in said chamber and is not expelled when the grease is topped up or the bearing is lubricated . This entails a reduction in the costs and maintenance times given that it is not necessary to clean the used-up and/or excess grease and remove the used-up grease .

According to one embodiment of the present invention, the seal comprises a second lip configured to be in contact so that it slides against the second element of the bearing, and in which the first lip is arranged between the compartment and the second lip .

According to one preferred embodiment of the present invention, the seal is annular and the chamber is toroidal .

According to one embodiment of the present invention, the seal comprises a hollow toroidal element defining the chamber .

According to one embodiment of the present invention, the tooth, the first lip, and, preferably, the second lip are made along an outer surface of the toroidal element and are connected thereto .

According to one preferred embodiment of the present invention, the chamber and the compartment are in communication with each other via first holes , preferably radial to the surface of the chamber, so that grease can flow from the compartment into the chamber . According to one embodiment of the present invention, first holes , preferably radial , are made on the hollow toroidal element so as to put the compartment in communication with the chamber inside the hollow toroidal element .

According to one embodiment of the present invention, at least one second hole , preferably radial to the surface of the toroidal element , is made on the hollow toroidal element to empty the grease accumulated in the chamber, the second hole being closable with a closing element , preferably a plug, and the closing element being configured to be removable so as to access the chamber to remove the grease , the second radial hole is preferably made along a side opposite the side on which the first radial holes are made .

Another aim of the present invention is to provide a bearing that reduces the drawback of the prior art .

According to the present invention, a bearing comprising a first seal according to one of claims 1 to 8 is provided .

According to one embodiment of the present invention, the bearing comprises : an outer first element , preferably an outer ring; and an inner second element , preferably an inner ring, which is coupled to the outer first element so it can rotate ; a groove , preferably an annular groove , is made along the outer first element or the inner second element , the tooth of the seal preferably being an annular tooth; the tooth of the seal is housed and secured within the groove .

According to one embodiment of the present invention, the first lip exerts pressure along an outer wall of the inner second element or the outer first element and the toroidal element is in contact with and exerts pressure along an outer wall of the outer first element or of the inner second element .

According to one embodiment of the present invention, the bearing is an axial one , in particular a slewing bearing .

According to one embodiment of the present invention, the bearing includes a second seal which is a hermetic seal and is located on an opposite side of the bearing with respect to the side where the first seal is located .

Another aim of the present invention is to provide a wind turbine that has lower costs and maintenance times compared to the prior art .

According to the present invention, a wind turbine is produced comprising a bearing according to one of the claims 9 to 13 .

According to one embodiment of the present invention, the wind turbine comprises a hub and at least one blade extending along an axis and coupled to the hub so it can pivot in relation to said axis so as to modi fy the wing area of the blade to be exposed to the wind; wherein the blade is coupled to the hub so it can pivot through said bearing .

Another aim of the present invention is to provide a ski li ft that has lower costs and maintenance times compared to the prior art .

According to the present invention, a cable transport system is provided comprising a cable , at least one cabin coupled to and towed by the cable , a pulley coupled to the cable so as to tow the cable , a pulley support structure , and a bearing according to one of claims 9 to 13 ; the pulley being connected to the pulley support structure so it can rotate via the bearing .

Another aim of the present invention is to provide a maintenance method for a bearing that reduces the drawback of the prior art .

According to the present invention, a method of maintaining a bearing is provided; the bearing comprising an outer first element , preferably an outer ring; an inner second element , preferably an inner ring, which is coupled to the outer first element so it can rotate ; a gap between the first element and the inner second element ; a first seal made according to any of claims 1 to 8 and arranged along a first side of the bearing and in contact with the first element and the second element ; and a second seal , preferably a hermetic seal , and arranged along a second side of the bearing opposite the first side and in contact with the first element and the second element ; the method comprising the step of : removing grease from the chamber of the first seal ; and, preferably, inj ecting grease into the gap .

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the attached drawings that illustrate some non-limiting embodiments thereof , in which :

- Figure 1 is a cross-section view, of a seal and a bearing comprising said seal produced in accordance with an embodiment of the present invention;

- - Figure 2 is an enlarged view of a detail in Figure 1 ; and

- Figure 3 is a schematic view of a detail of the seal in Figure 1 ;

- Figure 4 is a view, with parts removed for clarity, of a detail of a wind turbine on which the bearing in Figure 1 has been installed.

BEST MODE FOR CARRYING OUT THE INVENTION

Figure 1 illustrates a bearing 101 comprising: an outer ring 102; an inner ring 102, coupling spheres 104 arranged between the outer ring 102 and the inner ring 103; a seal 110 arranged along an inner annular surface 111 of the bearing 101 and a seal 112 arranged along an outer annular surface 113 of the bearing 101.

The seals 110 and 111 are arranged on opposite sides of the bearing.

In particular, the bearing 101 is an axial-type bearing, especially a slewing bearing.

With reference to Figures 1 and 2, the bearing 101 has a gap 120 that is defined between the inner ring 102, the outer ring 103, the spheres 104, and the seals 110 and 112. The gap 120 is filled with grease to lubricate the bearing.

The seal 110 is a hermetic seal; as a result, it does not allow the grease contained in the gap 120 to be expelled along the annular surface 111.

With reference to Figure 2, the seal 112 comprises a tooth 1, a first lip 2, a second lip 3, and a hollow toroidal element 4.

The ring 102 of the bearing 101 has a groove 130 made along an annular surface 131, in particular an outer side surface, of the ring 102.

The tooth 1 is inserted, and preferably fixed by way of interference, to the inside of the groove 130.

The lip 2 is coupled to the ring 103 so it can slide, in particular it is held in sliding contact with an annular surface 132, in particular an upper outer one, of the ring 103.

In addition, the first lip 2 is arranged between the second lip 3 and the tooth 1 .

The second lip 3 is arranged in a position further out than the position of the first lip 2 .

The lip 3 is coupled to the ring 103 so it can slide , in particular it is held in sliding contact with the annular surface 132 , in particular an upper outer one , of the ring 103 .

In other words , the first lip 2 and the second lip 3 exert a pressure along the annular surface 132 of the ring 103 . This pressure is exerted thanks to the fact that the toroidal element 4 is in contact and abuts against the surface 131 of the ring 102 .

The seal 112 defines a compartment 140 delimited, on one side , by the lip 2 and, on the other side , by the tooth 1 .

The compartment 140 is in communication with the gap 120 of the bearing 101 .

The seal 112 has a chamber 134 defined by an inner hollow of the seal 112 .

In particular, the chamber 134 is defined by the inner cavity of the hollow toroidal element 4 .

The chamber 134 is coupled to the compartment 140 via holes 142 radial to the surface of the chamber so that the grease can flow out from the compartment 140 towards the chamber 134 .

In use , the chamber 134 collects grease that is expelled from the gap 120 .

In particular, the grease from the gap 120 flows into the compartment 140 and, subsequently, flows into the chamber 134 via the radial holes 142 .

The seal 112 is an annular seal and the chamber 134 is toroidal . In particular, the tooth 1 , a lip 2 , and a lip 3 are annular . The groove 130 is annular . The compartment 140 is annular .

The tooth 1 , the lip 2 , and the lip 3 are made along an outer surface of the toroidal element 4 and are connected thereto .

With reference to Figure 3 , the hollow toroidal element 4 has at least one radial hole 150 for emptying the grease accumulated in the chamber 134 .

In use the radial hole 150 is closed with a closing element 151 , preferably a plug, which is configured to be removable so as to access the chamber 134 to remove the grease , the radial hole 150 is preferably made along a side opposite the side on which the radial holes 142 are made .

In one alternative embodiment to the preceding one , the seal 110 is arranged along the outer annular surface 113 of the bearing 101 and the seal 112 is arranged along the inner annular surface 111 of the bearing 101 .

In use , the excess or used-up grease is collected in the chamber 134 from which it is possible to remove it via a pump and/or a tube , removing the closing element 151 and removing the grease from the chamber 134 through the hole 150 .

In one alternative embodiment , the hollow toroidal element 4 has at least two radial holes 150 for emptying the grease accumulated in the chamber 134 .

In one alternative , non-limiting embodiment of the present invention, the excess or used-up grease is removed from the chamber 134 via a piston or fluid inserted in one of the two radial holes 150 that is pushed along the chamber 134 so that the grease is expelled from the chamber 134 through the other of the two radial holes 150 . Thanks to the chamber 134 that functions as a used-up or excess grease collection reservoir, and to the first lip 2 , and to the second lip 3 , the grease is not expel led from the seal , in particular when new grease is pumped or during normal operation and, thus , does not dirty the parts to which the bearing is connected . This simpli fies and speeds up the greasing and general bearing maintenance operations , as well as making them more economical , since it is enough to remove the grease from the chamber 134 , through the at least one hole 150 , instead of needing to clean the expelled grease that , in the prior art, dirties the parts connected to the bearing and the bearing itsel f .

More speci fically, during the bearing greasing step, the following steps are carried out : a ) the used-up grease in the chamber 134 is removed, preferably using a pump, after having removed the closing element 151 and accessing the chamber 134 through the radial hole 150 ; b ) the radial hole 150 is closed again with the closing element ; c ) the seal 110 is removed; d) grease is inj ected into the gap 120 on the side of the bearing 101 corresponding to the removed seal 110 ; e ) the seal 110 , which may be the one previously removed or a new seal 110 of the same time as the one removed, is inserted; f ) the used-up and/or excess grease in the chamber 134 is removed, preferably using a pump, after having removed the closing element 151 and accessing the chamber 134 through the radial hole 150 ; g) the radial hole 150 is closed again with the closing element .

Thanks to the steps mentioned above , the bearing 101 is greased and the used-up grease is removed quickly and inexpensively without dirtying the parts on which the bearing 101 is mounted and without needing to clean the grease expelled by the bearing as occurs in the prior art .

In another embodiment , the ring 102 is an inner one and the other ring 103 is an outer one .

In other words , the outer elements and the inner elements ( rings or surfaces and related seal s ) may be inverted without changing the substance of the invention .

A particularly advantageous application for the bearing 101 is in a wind turbine .

With reference to Figure 4 , a wind turbine 201 is illustrated, which comprises a vertical support structure 202 , for example a pylon; a nacelle 203 connected so it can rotate around the vertical support structure 202 about an axis Al ; a hub 204 connected so it can rotate around the nacelle 203 about an axis A2 ; and three blades 206 , each of which is connected so it can rotate around the hub 204 .

In addition, the wind turbine 201 comprises an electric rotating machine , in particular an electric generator connected to the nacelle 203 and to the hub 204 . In particular, a stator of the electrical generator is connected to the nacelle 203 and a rotor of the electrical generator is connected to the hub 204 .

The wind turbine 201 comprises three bearings 101 , each of which connects one of the three blades 206 to the hub 204 so it can rotate . In particular, the outer ring 102 is connected to the hub 204 and the inner ring 103 is connected to the blade 206 . In one alternative embodiment , the inner ring 103 is connected to the hub 204 and the outer ring 102 is connected to the blade 206 .

Thanks to the present invention, the bearings 101 of the wind turbine 201 do not dirty the hub 204 or other parts of the wind turbine 201 with grease , either during normal operation or when the bearings 101 are periodically greased . As a result , it is not necessary to schedule cleaning of the hub 204 or of other parts of the bearing 101 and this makes the maintenance of the wind turbine 201 more economical and quicker, even considering the si ze and di f ficulties of cleaning the hub 204 that is located at a considerable height above the ground .

In one embodiment , the wind turbine 201 comprises the bearing 101 to connect the nacelle 203 to the vertical support structure 202 . In this case , the outer ring 102 or the inner ring 103 is connected to the vertical support structure 202 and the inner ring 103 or the outer ring 102 is connected to the nacelle 203 , in particular to a base , preferably hollow, of the nacelle 203 .

In one embodiment , the wind turbine 201 comprises the bearing 101 to connect the electric rotating machine to the hub 204 .

In particular, the outer ring 102 or the inner ring 103 is connected to the electric rotating machine and the inner ring 103 or the outer ring 102 is connected to the hub 204 .

As is clear from the description, the wind turbine 201 may comprise multiple bearings 101 to connect di f ferent parts of the wind turbine rotating with each other .

Another particularly advantageous application for the bearing 101 is in a cable transport system .

A cable transport system comprises at least one cable ; one passenger transport unit , preferably multiple passenger transport units , coupled to the cable in order to be dragged by it ; a pulley coupled to the cable to drag the cable ; and a pulley support structure . The pulley is connected to the support structure so it rotates around an axis .

The cable transport system comprises the bearing 101 to connect the pulley to the support structure so that it rotates .

In particular, the outer ring 102 or the inner ring 103 is connected to the pulley and the inner ring 103 or the outer ring 102 is connected to the support structure .

Finally, it is clear that the seal and the rotating machine described may be modi fied, and variants may be produced thereof , without departing from the scope of the present invention, as defined in the attached claims .