Support assembly with improved sealing for food applications

Abstract

A support assembly (1) for a live, rotating or sliding shaft (5) has a bearing unit (2), a housing (3) and a cover (10) for a fluid-tight opening (11) of an inner seat (4) of the housing; the cover has an annular coupling portion (14) with a radially external lateral surface (16) facing the housing, which is provided, on the radially internal side, with at least one pair of teeth (20) projecting radially towards the internal side of the cover and circumferentially spaced apart from each other; the radially external lateral surface of the housing is provided with an annular groove (22) for receiving the teeth of the cover, which in turn is provided circumferentially with an alternation of recesses (26) and protrusions (27); the annular coupling portion of the cover is provided with a plurality of radially internal protrusions (40) which, in sequence along a circumferential portion without axial slots (24), engage the lateral surface of the housing and the corresponding recesses in the annular groove of the housing.

Description

Technical Field

[0001] This invention relates to a novel fastening system between the housing and the lid of a support assembly for food applications. Specifically, the support assembly is fixed to a machine frame and serves to support movable shafts, such as rotating shafts, by means of suitable bearing units.

[0002] The novel fastening system improves the installation of the cover on the housing, especially improving the sealing performance. Background Technology

[0003] It is well known that in the food industry (also known as "food and beverage ( / catering)", or simply "F&B"), there is a growing interest in developing new machines and machine designs to improve food safety and quality.

[0004] In addition, it is well known that machines used in the food industry have many moving parts supported by rotating or sliding shafts, such as conveyor belts, mixers, and machines for cleaning fresh food.

[0005] All these machines must be cleaned frequently, typically with water already treated with detergent and / or disinfectant, to control the growth of any bacterial colonies that could contaminate food. In particular, these machines must be free of any gaps or other areas where dirt or even wash water can penetrate and stagnate. This is because stagnation of liquid or moisture promotes the potential proliferation of bacteria.

[0006] This problem is particularly severe for support assemblies used for moving shafts, which can be terminal type, shaft-receiving end type, or through type. These support assemblies consist of a housing, bearing unit, and cover. The housing is typically annular and has a base or flange for fixing to the machine. The bearing unit is located inside the housing and connected to the moving shaft. The cover is typically cup-shaped and press-fitted to the housing in such a way that the connecting portion of the cover forms a fluid seal with the radially outer lateral surface of the housing.

[0007] For known types of forced mounting, the cover must be fitted onto the outside of the housing via, for example, a snap-fit, or by engaging a groove formed on the radially outer lateral surface of the housing. The cover has multiple teeth in the groove engaging the housing. Within the groove of the housing, there are protrusions in the form of rising and falling ramps for locking the teeth of the cover in the circumferential direction.

[0008] In other words, during the installation process, the cover is positioned on the housing, and the teeth of the cover reach the groove of the housing through the corresponding opening on the outer surface of the housing. Then, in a typical bayonet coupling, the cover is rotated and the teeth of the cover move along the groove of the housing past the corresponding protrusion. The cover is thus locked, although it can still be rotated through a circumferential arc until the next protrusion. Two consecutive protrusions are angularly spaced so that the teeth of the cover are not located near an opening on the outer surface of the housing through which the teeth of the cover may disengage, thus causing the cover to be demounted.

[0009] Strictly speaking, the cap's connecting portion does not provide a sealing function for the housing during the cap installation process, as the profile is not optimized for the housing shape. Specifically, during installation, the sealing lip of the cap's connecting portion tends to open; in other words, the sealing lip of the cap's connecting portion tends to deform in a radially outward direction. Therefore, a seal between the cap and the housing cannot be guaranteed, especially during cleaning processes using substantial amounts of fluid.

[0010] Therefore, it is necessary to define a support component that provides a novel design solution that can solve or at least mitigate the aforementioned drawbacks. Summary of the Invention

[0011] In order to fundamentally solve the above-mentioned technical problems, one object of the present invention is to define a novel support assembly for food applications, particularly a support assembly for a rotating shaft and a corresponding bearing unit fixed to a machine frame.

[0012] To this end, according to one aspect of the invention, in order to improve the operation of mounting the cover on the housing, and in particular to improve the fluid sealing performance of the entire support assembly, the cover of the support assembly is provided with a radially internal protrusion, the cross section of which is different from the cross section of the teeth of the cover used for snap fastening.

[0013] These additional protrusions improve cover installation because they provide a larger opening in the radially outward direction during axial connection with the housing and prevent the sealing lip from deforming when in contact with the housing.

[0014] Therefore, according to the present invention, a support assembly for food applications is provided for a movable shaft, a rotating shaft, or a sliding shaft, the support assembly comprising a bearing unit adapted to receive the movable shaft, a housing, and a cover for fluid-sealing an opening of an inner seat of the housing; - the cover includes an annular connecting portion toward a radially outer lateral surface of the housing, the annular connecting portion having at least one pair of teeth on a radially inner side, the at least one pair of teeth projecting radially toward the inner side of the cover and spaced apart from each other in the circumferential direction; - The outer radial side surface of the housing is provided with an annular seat for receiving the teeth of the cover. The annular seat includes an annular groove configured to be axially spaced relative to the front edge of the housing defining the opening and connected to an axial groove. The number of axial grooves is equal to the number of teeth present on the cover, and the axial grooves radially interrupt at least a portion of the front edge. In the bottom wall of the annular groove, which is provided with a plurality of alternating recesses and protrusions in the circumferential direction, the protrusions are configured to be offset in the circumferential direction relative to the axial groove. The annular connecting portion of the cover is provided with a plurality of radially inner protrusions that sequentially engage with the side surface of the housing along a circumferential portion without an axial groove and with corresponding recesses in the annular groove of the housing. Attached Figure Description

[0015] The invention will now be described with reference to the accompanying drawings, which illustrate non-limiting examples of embodiments of the invention, wherein: - Figure 1 A cross-section of a support assembly according to an embodiment of the present invention is shown. - Figure 2 It shows Figure 1 A front view of the housing of the supporting components. - Figure 3 Shown at magnified scale Figure 2 Details - Figure 4 It shows Figure 1 Side view of the cover supporting the components. - Figure 5 It shows Figure 1 A front view of the cover of the supporting components, and Figures 6 and 7 show two details of the corresponding connection between the outer shell and the cover. Detailed Implementation

[0016] By way of non-limiting example only and with reference to the above figures, the number 1 indicates the whole of the support assembly for a movable axis, a rotating axis or a sliding axis (the axis is not shown for simplicity).

[0017] The support assembly 1 also includes a bearing unit 2 and a housing 3. For example, the bearing unit 2 is a rolling bearing of a known type, capable of accommodating the movable shaft 5, such as a rotating shaft, in a known manner. The housing 3 has a through seat 4 in which the bearing unit 2 is stably and knownly accommodated.

[0018] Specifically, the support assembly 1 is used for mounting on machinery used in the food industry. For this purpose, the housing 3 (such as...) Figure 2 (As shown in the front view) It has a type for fixed mounting on a frame of a known machine (particularly for machines used in the food industry, not shown for simplicity).

[0019] The housing 3 has an integral annular shape and is designed to accommodate the bearing unit 2 therein in a known manner, particularly in the through seat 4. The housing also includes a base or flange 8 for fixing to the frame of the machine; the seat 4 has a total axis of symmetry X, which is also the axis of symmetry of the housing 3.

[0020] Obviously, Figure 2 The embodiment of the housing 3 shown is only one of the possible embodiments; for example, the square base or flange 8 in the illustrated example may have other symmetrical or asymmetrical shapes.

[0021] In any case, the support assembly 1 also includes a cover 10 for the opening 11 of the through seat 4 of the fluid-sealed housing 3.

[0022] The cover 10 for the housing 3 is generally bowl-shaped and includes a bottom wall 12, an annular side wall 13 extending laterally relative to the bottom wall 12, and a connecting portion 14 facing the housing 3.

[0023] The connecting portion 14 is annular and designed to be laterally connected to the housing 3 on the outside of the housing during use. In particular, the connecting portion 14 is shaped as a socket joint and is radially and laterally connected to the outer side of the radially outer lateral surface 16 of the housing 3.

[0024] Lateral surface 16 and connecting portion 14 are defined by a solid of revolution and share a common axis of symmetry, which in the illustrated example coincides with the axis of symmetry X of cover 10. Figure 1 ) overlaps and is also the axis of symmetry between the outer shell 3 and the through seat 4.

[0025] The cover 10 is made of a suitable synthetic plastic material as a single piece, and the connecting portion 14 is provided with an annular sealing lip 18 on the opposite side of the bottom wall 12, the sealing lip 18 extending from the front edge 19 of the connecting portion 14. Figure 4It extends forward and is made of the same synthetic plastic material as the cover 10, so that it can elastically deform from the inside to the outside in the radial direction.

[0026] The connecting portion 14 of the cover 10 is provided with at least a pair of teeth 20 on its radially inner side. These teeth 20 project radially toward the inner side of the cover 10 and are spaced apart from each other in the circumferential direction. Each tooth extends on a defined circumferential portion of the connecting portion. Figure 5 In the non-limiting example shown, the number of teeth 20 is four and they are spaced apart from each other at 90°.

[0027] According to one aspect of the invention, in order to improve the operation of mounting the cover on the seat, and especially to improve the fluid sealing performance of the entire support assembly, the annular connecting portion 14 of the cover 10 of the support assembly 1 is further provided with a plurality of radially internal protrusions 40, the plurality of radially internal protrusions 40 having an end cross section different from the end cross section of the teeth 20 used for bayonet fastening. In particular, the protrusions 40 are provided with a convex end surface 40a (FIG. 7).

[0028] like Figure 5 As shown in the illustrated example of the embodiment, these additional protrusions 40 may be four in number and alternate with the teeth 20. Therefore, the protrusions 40 will also be angularly spaced at 90° to each other, and the angular distance between the protrusions 40 and the subsequent teeth 20 will be 45°. The protrusions 40 are essential to the invention, and due to their specific shape and size, the protrusions 40 serve to improve the mounting of the cover on the housing, as explained more fully below.

[0029] In combination with the presence of the teeth 20 on the cover 10, the radially outer lateral surface 16 of the housing 3 is provided with an annular seat 21 for receiving the teeth 20 of the cover 10. The annular seat 21 includes an annular groove 22, which is configured to be axially spaced relative to the front edge 23 of the defining opening 11 of the housing 3 and is provided with axial grooves 24, the number of which is equal to the number of teeth 20 present on the cover 10, and these grooves 24 radially interrupt at least a portion of the front edge 23 of the housing 3.

[0030] The bottom wall 25 of the annular groove 22 is provided with a plurality of alternating recesses 26 and protrusions 27 in the circumferential direction, the protrusions 27 being configured to be offset (or staggered) relative to the axial groove 24 in the circumferential direction.

[0031] The radial depth of the axial groove 24 is equal to the radial depth of the annular groove 22 at the position of the axial groove 24, so that the corresponding bottom wall of the axial groove is flush with the bottom wall 25 of the radial groove 22.

[0032] In the preferred example of the illustrated embodiment, the cover 10 has two pairs of teeth 20 configured to be symmetrically spaced and offset by 90° in the circumferential direction. In this case, the radially outer lateral surface 16 of the outer casing 3 has two pairs of axial grooves 24 symmetrically spaced and offset by 90° in the circumferential direction. The bottom wall 25 of the annular groove 22 has a plurality of circumferential sectors of equal angular size, including eight recesses 26 and eight protrusions. Four of the eight recesses 26 are axially defined by edges 23, and the other four are free and disposed at the location of the groove 24. The recesses 26 are defined by curved surfaces flush with the bottom wall 25 of the annular groove 22, while the protrusions 27 protrude radially relative to the bottom wall 25 of the annular groove 22 and are alternately arranged with the recesses 26.

[0033] Advantageously, the annular groove 22 ( Figure 3 The protrusions 27 of the annular groove 22 each include a first circumferential portion 29 with a flat surface that rises (or is raised) relative to the bottom wall 25 of the annular groove 22, and second and third circumferential portions 30 and 31 with flat surfaces, respectively. The second and third circumferential portions 30 and 31 are located on either side of the first portion 29 and form two inclined planes connecting the first portion 29 with the bottom wall 25 of the annular groove 22. These two inclined planes are characterized by having different sloping angles, thus the protrusions 27 take the form of asymmetrical slopes. Specifically, as... Figure 3 As shown, the inclination of the second circumferential portion 30 with a flat surface (in other words, it is less steep) is less than the inclination of the third circumferential portion 31 with a flat surface (which is steeper).

[0034] Advantageously, the annular groove 22 has at least one pair of mechanical stops 32, which are further protrusions relative to the bottom wall 25 of the annular groove 22. The protrusions 32 project radially relative to the corresponding recesses 26 and extend to be flush with the lateral surface 16 of the housing 3. The introduction of this feature forms end stops for the teeth 20 of the cover 10 during the installation process; therefore, the number of mechanical stops 32 is equal to the number of teeth 20 of the cover 10.

[0035] The protrusion 40 plays a fundamental role in improving the mounting of the cover 10 on the housing 3 by allowing the cover 10 to have a larger opening during axial coupling to the housing 3, and in particular in improving the fluid seal between these components by preventing deformation of the coupling portion 14 (especially preventing deformation of the annular sealing lip 18 of the cover 10).

[0036] Specifically, the installation of the cover 10 onto the housing 3 requires a first step of axially connecting the two components and a second step of rotating the cover relative to the housing. In other words, in the installation step, the cover 10 is first positioned on the housing 3, and the teeth 20 of the cover 10 enter the annular groove 22 of the housing 3 along the lateral surface 16 of the housing 3 via the corresponding axial groove 24 at the position of the recess 26 of the annular groove 22. Then, in the second step, a bayonet connection is formed by rotating the cover 10 so that the teeth 20 of the cover 10 ride over the corresponding protrusion 27 along the annular groove 22 of the housing 3.

[0037] Referring also to Figures 6 and 7, during the first connection step (connection in the axial direction as indicated by the arrow), the protrusion 40 is connected to the lateral surface 16 of the housing 3 along the circumferential portion without the axial groove 24. Therefore, during the first step of installation, there is no contact between the sealing lip 18 of the cover 10 and the lateral surface 16 of the housing 3, even in the truncated conical portion 17 of the lateral surface 16 of the housing 3. Therefore, there is no interference, and thus no stress state on the sealing lip 18, thereby preventing the lip from bending relative to the housing 3.

[0038] On the other hand, in the second step of installation (bayonet connection), when the teeth 20 of the cover 10 pass over (or ride over) the corresponding protrusion 27 along the annular groove 22 of the housing 3, the protrusion 40 also rotates and is no longer under stress because the protrusion 40 reaches the corresponding recess 26 in the annular groove 22 of the housing 3. In this step, that is, when the cover is installed on the housing, the lateral surface 16 of the housing contacts the sealing lip 18, providing better sealing performance.

[0039] The design of Protrusion 40 is very complex and various factors must be taken into account.

[0040] First, the dimensions of the annular groove 22 must be considered. The depth H of the annular groove 22 in the radial direction is determined by the following formula: H= (D le – D h ) / 2 in D le ( Figure 2 () is the diameter of the side surface 16 of the outer casing 3. D h ( Figure 2 ) is the diameter of the bottom wall 25 of the annular groove 22.

[0041] Therefore, the width W of the protrusion 40 in the axial direction must be sufficient to allow the protrusion to be accurately inserted into the annular groove 22. It must be as follows: W≤H–2mm The limitation of the width W of the protrusion 40 is necessary to ensure that when the cover 10 is installed and rotated to close it on the housing, the profile of the protrusion 40 always enters the annular groove 22 with a certain safety margin.

[0042] The specifications of the radius of curvature R of the convex end surface 40a and the radial thickness of the protrusion 40 are also very important. Advantageously, as revealed by the dynamic simulations performed, the radius of curvature R must be: R≤0.4mm The radial thickness D of protrusion 40 must be: 0.6mm≤D≤0.8mm With this sizing choice, the connection between the protrusion 40 of the cover 10 and the lateral surface 16 of the housing 3 allows the first installation step (axial connection) to be completed without any interference between the annular sealing lip 18 of the cover 10 and the truncated conical portion 17 of the lateral surface 16 of the housing 3.

[0043] Furthermore, the value of the radial thickness D is also helpful during the process of removing the cover 10, as the circular profile with the convex surface 40a slides on the annular groove 22 of the housing 3 and releases the annular sealing lip 18 of the cover when the protrusion 40 is located on the lateral surface 16 of the housing.

[0044] Finally, due to the introduction of the new protrusion 40 on the cover 10, the support assembly 1 can be certified for use as a new unit in the "food and beverage" production line because it can provide: - Better sealing performance when covering the housing, because the sealing lip does not deform during installation; - Better axial connection to secure the cover to the housing.

[0045] In addition to the embodiments of the present invention described above, it should be understood that many other variations exist. It should also be understood that these embodiments are described by way of example only and do not limit the purpose of the invention, its application, or its possible construction. Rather, while the above description enables those skilled in the art to practice the invention according to at least one example of its embodiments, it should be understood that many variations of the described components are possible without departing from the purpose of the invention.

Claims

1. A support assembly (1) for a movable shaft, a rotating shaft or a sliding shaft (5), the support assembly (1) comprising a bearing unit (2) adapted to receive the movable shaft, a housing (3) and a cover (10) for fluid sealing an opening (11) of an inner seat (4) of the housing (3). - The cover (10) includes an annular connecting portion (14) facing the radially outer lateral surface (16) of the outer shell (3), the annular connecting portion (14) having at least one pair of teeth (20) on the radially inner side, the at least one pair of teeth (20) protruding radially toward the inner side of the cover and spaced apart from each other in the circumferential direction. - The radially outer lateral surface (16) of the housing (3) is provided with an annular seat (21) for receiving the teeth (20) of the cover, - the annular seat (21) includes an annular groove (22) configured to be spaced axially relative to the front edge (23) of the housing (3) defining the opening (11) and connected to an axial groove (24), the number of axial grooves (24) being equal to the number of teeth (20) present on the cover, and the axial grooves (24) interrupting at least a portion of the front edge (23) radially; in the bottom wall (25) of the annular groove (22) provided with alternating recesses (26) and protrusions (27) in the circumferential direction, the protrusions are configured to be offset circumferentially relative to the axial grooves (24); The support assembly (1) is characterized in that the annular connecting portion (14) of the cover (10) is provided with a plurality of radially internal protrusions (40), which sequentially engage with the lateral surface (16) of the outer shell (3) along the circumferential portion without the axial groove (24) and engage with the corresponding recess (26) in the annular groove (22) of the outer shell (3). The radially inner protrusion (40) has an end section that is different from the end section of the tooth (20) used for bayonet fastening.

2. The support component (1) according to claim 1, characterized in that, The plurality of radially inner protrusions (40) have convex end surfaces (40a).

3. The support component (1) according to claim 1 or 2, characterized in that, The annular groove (22) has at least one pair of mechanical stops (32) for at least one pair of teeth (20) of the cover (10), the mechanical stops (32) extending in the radial direction relative to the corresponding recess (26) to be flush with the lateral surface (16) of the outer shell (3).

4. The support component (1) according to claim 1 or 2, characterized in that, The protrusions (27) of the annular groove (22) include a first circumferential portion (29) with a flat surface that protrudes relative to the bottom wall (25) of the annular groove (22), and a second circumferential portion (30) and a third circumferential portion (31) with flat surfaces. The second circumferential portion (30) and the third circumferential portion (31) are on both sides of the first circumferential portion (29) and form two inclined planes that connect the first circumferential portion (29) with the surface to the bottom wall (25) of the annular groove (22). The inclination of the second circumferential portion (30) is less than that of the third circumferential portion (31), thereby making the protrusions (27) have an asymmetrical shape.

5. The support component (1) according to claim 1 or 2, characterized in that, The number of the plurality of radially inner protrusions (40) is equal to the number of the teeth (20).

6. The support component (1) according to claim 5, characterized in that, The number of the plurality of radial inner protrusions (40) is four, which alternate with the teeth (20) and are angularly spaced at 90° from each other, while the angle between the radial inner protrusions (40) and the subsequent teeth (20) is 45°.

7. The support component (1) according to claim 1 or 2, characterized in that, The relationship between the width (W) of the radially inner protrusion (40) in the axial direction and the width (H) of the annular groove (22) is as follows: W≤H–2mm.

8. The support component (1) according to claim 2, characterized in that, The radius of curvature (R) of the convex end surface (40a) of the radially inner protrusion (40) follows the following relationship: R≤0.4mm.

9. The support component (1) according to claim 1 or 2, characterized in that, The radial thickness (D) of the radially inner protrusion (40) follows the following relationship: 0.6mm≤D≤0.8mm.

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