1. A housing element (10) for use in a manufacturing machine, comprising:

-a housing (40) provided with a spherical seat (41),

-a bearing unit (30) located inside a spherical seat (41) of the housing (40),

-a plastic end cap (20) provided with a radial hole (24) therethrough, so that a mechanical shaft (50) can be inserted inside, wherein said end cap (20) is constrained to said shaft (50) and can rotate together with said shaft (50),

the housing element (10) is characterized in that the end cap (20) is provided with a resilient sealing member (60) to achieve a static seal on the shaft (50).

2. The housing element (10) according to claim 1, characterized in that it has a first interference between a radially inner edge (21) of the end cap (20) and two projections (61) of the sealing member (60), said two projections (61) being placed radially outwards with respect to said edge (21) and by means of opposite bands, so that the assembly of the sealing member (60) on the end cap (20) is performed.

3. The housing element (10) of claim 1, wherein the sealing member (60) is overmolded on the end cap (20).

4. The housing element (10) according to any one of the preceding claims, characterised in that the material of the elastic sealing component (60) is polytetrafluoroethylene.

5. A housing element (10) according to claim 4, characterized in that the material of the sealing member (60) is polytetrafluoroethylene resistant to temperatures up to 150 ℃.

6. Housing element (10) according to any one of the preceding claims, characterized in that the plastic material of the end cap (20) is polyamide.

7. The housing element (10) according to any one of the preceding claims, characterized in that the end cap (20) is provided with two recesses (22), the two recesses (22) being placed radially outwards with respect to the symmetry axis (Y) of the end cap (20) and by means of opposing strips.

8. The housing element (10) according to any one of the preceding claims, characterised in that it has a second interference between a radially outer surface (33a) of a radially inner ring (33) of the bearing unit (30) and a radially inner surface (23) of the end cover (20), so that the assembly of the end cover (20) on the radially inner ring (33) is performed.

9. The housing element (10) according to claim 8, characterized in that the second interference has a value ranging between 0mm and 0.085 mm.

Background

It is well known in the manufacturing industry that attention is often focused more and more on developing new machines and machine designs aimed at improving the safety level and quality of the finished product. The housing components for such machines typically include an outer shell and end caps, and are designed for various machining operations.

The housing element is fixed to the frame of the machine and, for a given machining operation, is connected to the rotating shaft of the machine by means of a bearing unit. In this case, the end cap of the housing element is referred to as an "open" type, since it must allow the machine shaft to pass through into the housing element. These housing elements may be made of a plastic material or a metal material, typically stainless steel.

One of the problems to be solved is to ensure an effective sealing of the housing element with respect to water or, more generally, any contamination from the external environment, for the people working in this sector. In particular, this problem exists, for example, in the food industry, but in general this is a problem that must be solved by the entire manufacturing industry, bearing in mind that these housing elements are mounted horizontally, so that the cover has exactly the function of protecting the bearing unit from dripping water.

In the case of a housing element with an open-type end cap, a seal between the shaft and the cap is necessary to ensure sealing against the outside. The seal is of the static type, since the cover is integrally fixed to the shaft by locking with the rotating ring of the bearing unit, and therefore the cover can rotate together with the shaft at the same angular velocity.

In particular, the known solution is that the end caps made of pressed steel or cast iron are locked on the shaft by special locking means (socket head cap screws, pins, etc.). However, these solutions do not ensure an effective seal, in particular for given requirements, for example in order to be able to reduce the weight of the housing element, the end cap is made of a plastic material.

There is therefore a need to define a housing element provided with an end cap with optimized sealing, which does not have the aforementioned drawbacks, i.e. the housing element is able to keep water and other contaminants generally outside the housing element itself, being excellent in terms of quality and safety.

Disclosure of Invention

The object of the present invention is to provide a housing element provided with an end cap with an optimized sealing means, which housing element does not have the above-mentioned disadvantages.

According to the present invention, there is provided a housing element (housing element) comprising a housing (case), a bearing unit and an end cap, the housing element having the features indicated in the appended claims.

Drawings

The invention will now be described with reference to the accompanying drawings, which show non-limiting examples of embodiments of the housing element, in which:

fig. 1 shows an isometric view of a housing element according to an embodiment of the invention;

figure 2 shows a cross-section of the housing element according to figure 1 mounted on a shaft for connection to a machine of known type;

figure 3 shows a detail of the assembly of the sealing member according to a preferred embodiment of the invention on the end cap of the housing element; and

fig. 4 shows a plan view of an end cap of a housing element according to another embodiment of the invention.

Detailed Description

Referring now to fig. 1 and 2, an embodiment of a housing element (housing element) according to the present invention is described below by way of example only.

With reference to fig. 1, a housing element 10 for applications in the manufacturing industry (for example, textile, mineral, motor vehicle or food industry) or for applications in agricultural machines or industrial plants comprises an outer shell 40 axially symmetrical with respect to an axis X, an end cap 20 and a bearing unit 30 housed inside the end cap 20. The housing element 10 forming part of the invention may be used in the aforementioned industrial applications so as to be fixed on (fixed for) a rack.

The bearing unit 30 further includes:

a fixed (/ stationary) (stationary) radially outer ring 31;

a radially inner ring 33 rotatable about a rotational central axis X of the bearing unit 30;

a row of rolling elements 32 arranged between the radially outer ring 31 and the radially inner ring 33, the rolling elements 32 being balls in this example.

Throughout the present description and claims, terms and expressions indicating positions and orientations such as "radial" and "axial" should be understood as being relative to the central axis of rotation X of the bearing unit 30.

The radially outer ring 31 is provided with a radially outer raceway 31 'and the radially inner ring 33 is provided with a radially inner raceway 33' to allow rolling of the rows of rolling members 32 arranged between the radially outer ring 31 and the radially inner ring 33. To simplify the illustration, reference numeral 32 will indicate both a single ball and a column of balls. Again for simplicity, the term "ball" may be used by way of example in this description and the accompanying drawings, instead of the more general term "rolling member" (and the same reference numerals will be used as well).

The bearing unit 30 is further provided with a sealing member 35 for sealing the bearing unit from the external environment. In the following, the sealing member 35 may also be more simply indicated as sealing member 35, which obviously should be understood to mean the same component.

The housing 40 is preferably made of cast iron, for example grey cast iron or steel or stainless steel, and the housing 40 is provided with a spherical seat 41, inside which the bearing unit 30 is accommodated.

The end cap 20 is made of a plastic material, for example black polyamide PA6CF30 (black-coloured polyamide PA6CF 30). The end cap 20 is provided with a radial through hole 24 to allow the insertion of a shaft 50 of a machine (known and therefore not described) therein. The end cap 20 is mounted such that the end cap 20 is integral with the shaft 50 and thus the end cap 20 is able to rotate at the same angular velocity as the shaft. The end cap 20 has a specific shape designed to ensure that water and contaminants do not penetrate into the interior of the housing element. This is achieved by assembling an elastic (/ elastomeric) (elastomeric) sealing member 60, for example made of polytetrafluoroethylene (PTFE or Teflon), on the end cap 20. The main features of the sealing member are as follows:

the sealing member 60 is designed to be suitable for non-sliding contact (i.e., to provide a static-type seal) because the shaft 50 and end cap 20 are integral with one another and therefore rotate at the same angular velocity. Thus, the static type of seal allows to achieve the best performance of the seal itself.

The elastomeric material of the sealing member 60 is a special compound (compound) capable of withstanding high temperatures, in particular temperatures up to 150 ℃.

Referring to fig. 3, which shows a detail of the assembly of the sealing member 60 on the end cap 20 of the housing element 10, it can be seen that the sealing member 60 is mounted on the end cap 20 by interference between the radially inner edge 21 of the end cap 21 and two projections 61 of the sealing member 20, the two projections 61 being radially outward (/ radially outward) and on opposite sides of the edge 21. Alternatively, assembly of the sealing member 60 on the end cap 20 may also be performed by overmolding.

Referring to fig. 4, which shows a plan view of the end cap 20 of the housing element 10, the end cap 20 is provided with two recesses 22, the two recesses 22 being radially inward and preferably on opposite sides of the symmetry axis Y of the cap. In this way, the end cap may be used in applications where the end cap is locked on the shaft by a suitable locking means of a known type, such as an Allen screw (Allen screw), a pin or similar element. This solution is therefore suitable for and compatible with the type of seal designed according to the invention, i.e. with a static seal between the end cap 20 and the shaft 50.

Alternatively, but still with the aim of obtaining a static seal between the end cap 20 and the shaft 50, the end cap 20 may be assembled in an interference manner on the radial inner ring 33 of the bearing unit 30. In particular, as shown in fig. 2, assembly is performed by means of interference between the radially outer surface 33a of the radially inner ring 33 and the radially inner surface 23 of the end cap 20. This assembly by interference integrally fixes the end cap 20 to the radially inner ring 33, which in turn integrally mounts the radially inner ring 33 on the shaft 50. In this way, the shaft 50, the radially inner ring 33 and the end cap 20 will be integral with each other and all can rotate at the same angular velocity. In this case, the effect will also be that the sealing member 60 will act in a static type seal.

It is important to determine the value of the interference between the radially outer surface 33a of the radially inner ring 33 and the radially inner surface 23 of the end cap 20. In fact, an excessive interference value would cause unacceptable deformations in the end cap 20, as previously mentioned, the end cap 20 being made of plastic material. Experimental tests carried out on a series of prototypes have shown that interference values ranging between 0mm and 0.085mm give the best performance.

To verify the performance of this new end cap provided with a static seal with an elastomeric sealing member (elastomeric sealing means), a series of tests were performed to answer the following questions:

is a new end cap allowed water to pass?

Is water able to penetrate and wet the shielding surface (/ guard surface) of the bearing unit (shielding surfaces)?

Two types of tests were performed. The first test involved allowing water droplets to fall between the shaft and the lid, while the second test involved allowing water droplets to fall again, but this time on the edge of the lid. Both tests were performed using 22 ℃ water and the water droplets were allowed to fall at a rate of 30 drops per minute for 10 minutes. At the end of the test, both tests confirmed that there was no water in the end cap and also on the shaded surface of the bearing unit.

In addition to the embodiments of the invention described above, it should be understood that many other variations exist. It should also be understood that the described embodiments are merely examples and do not limit the purpose of the invention or its applications or possible configurations. On the contrary, although the description provided above enables a person skilled in the art to carry out the invention in at least one of its constructional examples, it must be understood that numerous modifications of the described components can be envisaged without thereby departing from the scope of the invention as defined in the appended claims, literally and/or according to their legal equivalents.