Seat element with axially displaceable bearing unit

Abstract

A seat element (10) comprises: a housing (40) provided with a cylindrical seat portion (41); a bearing unit (30) located inside the cylindrical seat portion (41) of the housing (40); a metal ring (50) arranged between the housing (40) and the bearing unit (30) and provided with a spherical seat portion (51), wherein the metal ring (50) is assembled inside the cylindrical seat portion (41) of the housing (40) and is movable in the axial direction along the cylindrical seat portion (41), the bearing unit (30) is coupled to the metal ring (50) via the spherical seat portion (51) of the metal ring (50) and is movable in the axial direction together with the metal ring (50), and the metal ring (50) is provided with a first groove (53) and a first radial hole (54), the first groove (53) being radially outside, the first radial hole (54) being fluidically connected to the first groove (53) to allow grease to be supplied to the bearing unit (30).

Description

Technical Field

[0001] The invention relates to a housing element with an axially displaceable bearing unit for use in the manufacturing industry.

[0002] In particular, the invention relates to a seat element with an axially movable bearing unit and is suitable for applications in which the shaft on which the bearing unit is mounted requires axial displacement, or in which the seat element and the bearing unit are subject to different thermal expansions and therefore require axial freedom of movement of the bearing unit. Background Art

[0003] It is known that a bearing unit operates correctly if its components (rings with raceways and associated rolling elements) are correctly lubricated with grease and if this grease is replenished during the operating life of the bearing unit so that the unit never operates dry or with insufficient grease.

[0004] A known type of housing element includes an external housing casing for a bearing unit, and grease may be supplied to the bearing unit via a conduit formed through the casing and connecting a grease reservoir with the bearing unit. This arrangement may not be effective if the bearing unit is movable in the axial direction, because displacement of the bearing unit may not allow sufficient grease access to its interior.

[0005] Figure 1A seat element 1 of known type is shown, comprising a housing 4 and a bearing unit 3, which is mounted so as to be movable in the axial direction inside the housing 4 and is provided with a radially inner ring 3a, which engages internally with the rotating shaft 2, and with a radially outer ring 3b having a spherical radially outer surface 3c with a convex appearance. The seat element 1 further comprises an inner cylindrical seat 4a and a metal ring 5, the inner cylindrical seat 4a being axially delimited by a side wall 4b of the housing 4, the metal ring 5 being radially mounted inside the inner cylindrical seat 4a to slide axially relative to the inner cylindrical seat 4a, and being radially arranged between the housing 4 and the radial outer ring 3b to allow axial displacement of the bearing unit 3 to a first operating position and a second operating position, in which the bearing unit 3 abuts against an elastic ring 6 located on a side of the metal ring 5 opposite to the side wall 4b, the elastic ring 6 being inserted into the interior of the inner cylindrical seat 4a, and in the second operating position, the bearing unit 3 abuts against the side wall 4b.

[0006] Still based on Figure 1 As shown in FIG, the seat element 1 of known type further comprises a radial duct 7 formed through the casing 4 at the inner cylindrical seat 4 a to allow grease (known and not shown) to be injected inside said inner cylindrical seat 4 a and thus to allow lubrication of the bearing unit 3.

[0007] Typically, so-called “standard” type bearing units are provided with an axial sealing screen 8 arranged between the inner and outer rings and axially on both sides relative to the rolling elements to prevent contaminants from entering the unit, but in the known solution described above, in order to allow lubrication of the bearing unit 3 by means of grease injection through the duct 7, only one sealing screen 8 can be used, and in order to protect the bearing unit 3 not only from external contaminants but also to prevent grease from escaping from the housing 4 itself, an external seal 9 is required, which is arranged radially between the side wall 4b of the housing 4 and the rotating shaft 2 or the radial inner ring 3a. Therefore, the solution described above not only does not allow the use of so-called “standard” type bearing units, but also leads to the need to use an additional external seal 9, thereby increasing production costs. Furthermore, since the bearing unit 3 is axially movable inside the inner cylindrical seat 4 a , injection of grease into the seat 4 a can be performed only when the bearing unit 3 is not in an axial position obstructing the outlet of the duct 7 .

[0008] The above comments illustrate disadvantages that reduce the possibilities of using the seat element 1 of known type and make its production particularly expensive and its maintenance relatively complicated.

[0009] There is therefore a need for a seat element with an axially displaceable bearing unit which does not have the aforementioned disadvantages, i.e. which not only allows the use of a so-called "standard" type of bearing unit with two axial sealing shields, if necessary, but also allows relubrication and maintenance operations to be carried out in a simple and linear manner without having to use various precautions. Summary of the Invention

[0010] The object of the present invention is to provide a housing element with an axially displaceable bearing unit which does not have the aforementioned disadvantages.

[0011] According to the present invention, there is provided a seat element with an axially movable bearing unit, the seat element comprising: a housing provided with a cylindrical seat portion,

[0012] a bearing unit provided with sealing means and allocated inside the cylindrical seat of the housing,

[0013] a metal ring, interposed between the housing and the bearing unit and provided with a spherical seat portion,

[0014] wherein the metal ring is assembled in a cylindrical seat of the housing and is movable in an axial direction along the cylindrical seat,

[0015] The bearing unit is coupled to the metal ring through the spherical seat portion and is movable in the axial direction together with the metal ring.

[0016] The metal ring is provided with a first groove and a first radial hole, the first groove being radially outer, the first radial hole being in fluid communication with the first groove to allow grease to be supplied to the bearing unit,

[0017] Axial movement of the metal ring and the bearing unit is limited by the elastic ring of the seat member and the wall of the housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention will now be described with reference to the accompanying drawings showing non-limiting examples of embodiments of a sealing system for food applications, in which:

[0019] Figure 1 shows a cross-sectional view of a seat element with an axially displaceable bearing unit according to the prior art;

[0020] Figure 2A sectional view showing a preferred embodiment of a seat element with an axially displaceable bearing unit according to the invention; and

[0021] Figure 3 is based on Figure 2 A perspective view of a detail of the seat element. DETAILED DESCRIPTION

[0022] Now refer to Figure 2 and Figure 3 , an embodiment of a housing element according to the invention with an axially displaceable (axially displaceable) bearing unit is described below purely by way of example.

[0023] Reference Figure 2 A seat element 10 for applications in the manufacturing industry (e.g., the textile, mining, or motor vehicle industries), or also for applications in agricultural machinery or industrial plants, comprises a casing 40 having axial symmetry with respect to an axis X, and a bearing unit 30 housed inside the casing 40. This seat element 10 can be used for fixing against a machine frame in the aforementioned industrial applications and forms part of the present invention.

[0024] The bearing unit 30 accordingly comprises:

[0025] The radial outer ring 31 is preferably, but not necessarily, stationary;

[0026] A radial inner ring 33 rotatable about the central rotation axis X of the bearing unit 30 ;

[0027] a row of rolling elements 32 , in this example balls, arranged between the radially outer ring 31 and the radially inner ring 33 ;

[0028] The cage 34 is used to accommodate the rolling elements so as to keep the rolling elements 32 of the rolling elements in a row in position.

[0029] Throughout the present description and in the claims, terms and expressions indicating position and orientation (such as “radial” and “axial”) should be understood as referring to the central rotation axis X of the bearing unit 30 .

[0030] Radially outer ring 31 is provided with a radially outer raceway 31', while radially inner ring 33 is provided with a radially inner raceway 33' to allow rolling of a row of rolling elements 32 arranged between radially outer ring 31 and radially inner ring 33. To simplify the graphical representation, reference numeral 32 will be assigned to both the individual balls and the row of balls. Again for the sake of simplicity, the term "ball" may be used by way of example in this specification and the drawings instead of the more general term "rolling element" (again, the same reference numerals will be used).

[0031] The bearing unit 30 is further provided with a sealing means 35 for sealing the bearing unit from the external environment. In the following, the sealing means 35 may also be more simply represented as a seal 50 which is obviously understood to indicate the same component.

[0032] The housing 40 is provided with a cylindrical seat 41 in which a metal ring 50 is movable in the axial direction, and the bearing unit 30 is accommodated inside the metal ring 50 inside a spherical seat 51 of the metal ring.

[0033] The metal ring 50 and, together with it, the bearing unit 30 can be displaced axially in two directions parallel to the axis x (as indicated by the double arrow F), and is limited on one axial side by a resilient ring 60 and on the opposite axial side by a radial wall 42 of the housing 40, which preferably has a length in the radial direction of not more than 6 mm.

[0034] Furthermore, the seat element 10 is provided with a radial duct 70 formed through the housing 40 in the region of the inner cylindrical seat 41 and thus in the region of the metal ring 50 for supplying grease to replenish the necessary amount of grease inside the bearing unit 30. The duct 70 is provided with a diameter that is larger than the axial displacement envisaged for the metal ring 50 and the bearing unit 30.

[0035] With this solution, a standard bearing unit can be used (i.e. with two seals 35 on both sides of the rolling element) because the metal ring 50 is provided with a first circumferential groove 53 and connected to the interior of the bearing unit 30, wherein the first circumferential groove 53 has an axial width such that the outlet of the grease supply duct 70 is intercepted in any position of the bearing unit 30 relative to the housing 40, and thus the grease supply function is always allowed.

[0036] Reference Figure 3 The metal ring 50 is provided with two radially inner recesses 52 diametrically opposed with respect to the axis of symmetry X. These two radially inner recesses 52 are required for inserting the bearing unit 30. Furthermore, the metal ring 50 is provided with a first (radially outer) groove 53 formed in its radially outer surface 53a. As already mentioned, this first groove 53 has an axial width such that it blocks the outlet of the conduit 70 in any position of the bearing unit 30 relative to the housing 40. Furthermore, the first groove 53 communicates with a first radial hole 54. This allows grease to pass through the first groove 53 and reach the first radial hole 54. This radial hole 54 is a through hole that passes through the metal ring 50. Grease reaches the bearing unit 30 through the radial hole 54.

[0037] More precisely, and with reference to Figure 2 The grease is supplied by following the path P. The grease is supplied through the duct 70 of the housing 40, then passes through the inside of the first groove 53 of the metal ring 50 and reaches the first radial hole 54. After passing through the radial hole 54, the grease reaches the second (radially inner) groove 55 located in the spherical seat 51 of the metal ring 50, and finally reaches the interior of the bearing unit 30 through the second radial hole 31" located inside the radial outer ring 31 of the bearing unit.

[0038] Preferably, the metal ring 50 can allow an axial displacement of not less than 5 mm, or the metal ring 50 can allow an axial displacement of not less than 2.5 mm for each displacement in the axial direction relative to the axis Y, wherein the axis Y is perpendicular to the axis of symmetry X and passes through the center plane of the bearing unit 30 .

[0039] Compared to other known embodiments, the tolerances of the spherical seat 51 between the metal ring 50 and the bearing unit remain unchanged. The connection between the metal ring 50 and the cylindrical seat 41 of the housing 40 is achieved with a slight interference ( / slight interference), using a tolerance of K7 (+10, -25) for the cylindrical seat 41 of the housing 40 and a tolerance of h7 (0, -35) for the radial outer surface 53a of the metal ring 50. This slight interference allows the metal ring 50 to be assembled and disassembled without applying excessive force, while preventing the metal ring 50 from rotating within the cylindrical seat 41.

[0040] In any case, having interference in the coupling is important because it prevents grease seepage between the casing and the metal ring (which would occur if the coupling had play) and prevents corrosion caused by contact between the ring and the cylindrical seat of the casing.

[0041] The material of the housing 40 can be cast iron, steel or stainless steel, while the material of the metal ring 50 is preferably aluminum. This enables significant weight reduction. Obviously, in the case where weight is not an issue, the metal ring 50 can also be made of steel.

[0042] The main advantages of this type of solution become clear from the description provided and, in any case, can be summarized as follows:

[0043] Use standard bearing units;

[0044] Since the bearing unit is provided with sealing components on both sides, it ensures optimal protection against contaminating agents;

[0045] The housing does not require additional sealing components;

[0046] Allows grease to be supplied in all possible positions of the metal ring and therefore in all possible positions of the bearing unit;

[0047] Ensure an axial displacement of at least 5 mm.

[0048] It should be understood that in addition to the embodiments of the present invention described above, many further variations are possible. It must also be understood that the embodiments described are merely examples and do not limit the subject matter of the present invention, its applications, or its possible configurations. On the contrary, although the description provided above enables a person skilled in the art to implement the present invention in at least one of its examples of configuration, it must be understood that many variations of the described components are possible without thereby departing from the scope of the present invention as defined in the appended claims, interpreted literally and / or in accordance with their legal equivalents.

Claims

1. A seat element (10), comprising: The housing (40) is provided with a cylindrical seat (41), a bearing unit (30), provided with a sealing member (35) and allocated inside a cylindrical seat (41) of said housing (40), A metal ring (50) is interposed between the housing (40) and the bearing unit (30) and is provided with a spherical seat portion (51). in The metal ring (50) is assembled in the cylindrical seat (41) of the housing (40) and is movable in the axial direction along the cylindrical seat (41). The bearing unit (30) is coupled to the metal ring (50) via the spherical seat portion (51) and is movable in the axial direction together with the metal ring (50). The seat element (10) is characterized in that the metal ring (50) is provided with a first groove (53) and a first radial hole (54), the first groove (53) being radially external, the first radial hole (54) being in fluid communication with the first groove (53) to allow grease to be supplied to the bearing unit (30), The axial movement of the metal ring (50) and the bearing unit (30) is limited by the elastic ring (60) of the seat member (10) and the wall (42) of the housing (40).

2. The seat element (10) according to claim 1, characterized in that A fluid path (P) for supplying grease to the bearing unit (30) is defined in sequence by a conduit (70) of the housing (40), a first groove (53) of the metal ring (50), a first radial hole (54) of the metal ring (50), a second groove (55) radially inwardly corresponding to the spherical seat (51) of the metal ring (50), and a second radial hole (31") located inside the radial inner ring (31) of the bearing unit (30).

3. The seat element (10) according to claim 1 or 2, characterized in that The axial movement of the metal ring (50) and the bearing unit (30) is not less than 5 mm.

4. The seat element (10) according to claim 3, characterized in that For each translation direction in the axial direction relative to the centerline axis (Y) of the bearing unit (30), the axial movement of the metal ring (50) and the bearing unit (30) is not less than 2.5 mm.

5. The seat element (10) according to claim 1 or 2, characterized in that The length of the radial wall (42) of the housing (40) in the radial direction is no more than 6 mm.

6. Seat element (10) according to claim 1 or 2, characterized in that The connection between the radial outer surface of the metal ring (50) and the cylindrical seat (41) of the housing (40) is achieved using tolerance grade K7 for the cylindrical seat (41) of the housing (40) and tolerance grade h7 for the radial outer surface of the metal ring (50).

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