The invention relates to an improved design for a hub bearing system.
It is known in the art to provide free and fixed rolling element bearing assemblies. Typically these comprise a clamp ring assembly (bearing inner race and clamp collars), a cage and rolling element assembly, and a bearing outer race (fitted into a bearing housing), all of which is positioned in use around a shaft.
Such roller bearing assemblies may be incorporated in hubs. Example applications of such assemblies include, but are not limited to, automotive and truck transmissions, agricultural and construction equipment, pumps and compressors, and two-cycle engines such as marine outboards and garden equipment.
Traditional rolling element bearing assemblies used in hubs are associated with problems of dirt ingress and contamination.
In some areas of implementation hubs are replaced on a regular basis. For example when used with agricultural equipment, hubs incorporating rolling element bearings are typically replaced once a season.
An aim of the invention is to provide an improved hub bearing system.
There is provided a replacement for traditional rolling element hub bearing assemblies which are more durable and hard wearing.
A seal free hub bearing system unit may be provided. Dirt and water can pass through the unit without causing damage.
Hubs can be replaced less frequently.
There is provided an improved hub bearing system which is seal free (i.e. non-lubricated). The improved hub bearing system utilises journal/plain/sliding bearings capable of supporting radial, axial and moment loads between two bodies rotating relative to each other about their shared axis of rotation.
The improved hub bearing system allows unidirectional or bidirectional relative rotation of a hub and a pin about their shared axis of relative rotation, whilst restricting relative rotation about the remaining two perpendicular axes. The improved hub bearing system also has to restrict bi-directional relative linear motion of the hub and the pin along all three perpendicular axes.
The journal/plain/sliding bearings are defined by two surfaces in motion relative to each other. There can be linear and/or rotational motion. Both surfaces are independent of each other at the bearing location, and it is the surfaces themselves that permit the relative motion.
Rolling element bearings are defined by two surfaces in motion relative to each other. There can be linear and/or rotational motion. Both surfaces are independent of each other at the bearing location, but the relative motion is permitted via the use of rolling elements, which are third entities in-between the two surfaces, enabling motion via rotation about their own rolling axis.
Loads are transmitted through elements rotating relative to each other—the hub bearing system is the system that avails the transfer of these forces across bodies rotating relative to each other.
Bearing components may be either fixed to the hub, fixed to the pin or neither fixed to hub or pin and merely enclosed within the system.
The external components may be fixed to either the hub or the pin, and both hub and pin may rotate relative to each other, and either may be stationary.
There is provided a hub bearing assembly comprising: a housing having an internal cylindrical opening; an annular bearing accommodated within the cylindrical opening of the housing; and a cylindrical pin accommodated within the annular bearing, wherein the housing and the cylindrical pin rotate relative to each other.
The internal cylindrical opening may be at least one void of revolution opening. The annular bearing may have a finite length. The annular bearing may be a solid of revolution. The cylindrical pin may be a solid of revolution.
The annular bearing may be fixed so that it rotates with the hub relative to the pin.
The annular bearing may be an integral part of the hub.
The annular bearing may be fixed so that it rotates with the pin relative to the hub.
The annular bearing may be an integral part of the pin.
The annular bearing may be accommodated between the housing and the cylindrical pin as an independent body.
The housing and the cylindrical pin rotate in the same direction or in opposite directions.
The hub bearing assembly may be configured to minimise relative rotation between the housing and the cylindrical pin about the two axes perpendicular to their common axis of rotation.
The annular bearing may have a finite length in the direction of the common axis of rotation.
The hub bearing assembly may be configured to minimise relative linear motion of the housing and the cylindrical pin along the common axis of rotation.
The hub bearing assembly may be configured to minimise relative linear motion of the housing and the cylindrical pin along the two axes perpendicular to their common axis of rotation.
The hub bearing assembly may be configured to minimise the linear motion of the housing and the cylindrical pin along the two axes perpendicular to their common axis of rotation bidirectionally and minimise the linear motion of the housing and the cylindrical pin along the common axis of rotation unidirectionally.
The relative linear motion along any of the common axis of rotation or the two axes perpendicular thereto is minimised by providing a bearing surface which is non-parallel to the shared axis of rotation.
The hub bearing assembly may further comprise a thrust element located adjacent the cylindrical pin, and having a thrust face towards the cylindrical pin.
The thrust element may be a washer.
The hub bearing assembly may further comprise a groove within the inner surface of the cylindrical opening, wherein the thrust washer is accommodated within the groove.
The hub bearing assembly may further comprise a first disc positioned between a first surface at the first end of the cylindrical steel pin and a surface of the thrust washer.
The hub bearing assembly may further comprise a second disc positioned at the other surface of the thrust washer.
The thrust element may be one of: fixed so it rotates with the housing relative to the cylindrical pin; fixed so it rotates with the cylindrical pin relative to the housing; accommodated between the housing and cylindrical pin relative rotating surfaces.
The annular bearing may comprise: a first annular bearing part between a first part of the cylindrical pin and the internal cylindrical opening of the housing; and a second annular bearing part between a second part of the cylindrical pin and the internal cylindrical opening of the housing.
The first annular bearing part may restrict linear motion along the common axis of rotation in a first direction, and the second annular bearing part restricts linear motion along the common axis of rotation in a second direction, the first direction being opposite to the second direction.
The bearing element may further comprise a pin extending from a position in the cylindrical.
The bearing element may further comprise a bolt for securing the second disc, the thrust washer and the first disc to the cylindrical steel pin.
The pin and thrust washer may rotate relative to the housing.
The housing may be fixed in position, and the pin and thrust washer rotate.
The housing may be fixed to a supporting frame.
The cylindrical steel pin may be connected to a rotatable element.
A second end of the cylindrical steel pin may be provided with a screw thread which is fitted to the rotatable element.
There is provided agricultural machinery comprising: a supporting frame; a housing comprising a cylindrical opening, the housing being fixably attached to the supporting frame; an annular bearing fitted to the cylindrical opening within the housing; and a cylindrical steel pin accommodated within the annular bearing, and having one end fixably attached to a rotating element.
The agricultural machinery may further comprise a thrust washer accommodated with the annular bearing, fixably attached to an other end the cylindrical steel pin.
There is provided a bearing element comprising: a housing comprising a cylindrical opening and having an annular groove within the cylindrical opening; an annular bearing fitted to the cylindrical opening; a cylindrical steel pin accommodated within the annular bearing; and a thrust washer accommodated within the annular groove.
The bearing element may further comprise a first disc positioned between a first surface at the first end of the cylindrical steel pin and a surface of the thrust washer.
The bearing element may further comprise a second disc positioned at the other surface of the thrust washer.
The bearing element may further comprise a pin extending from a position in the cylindrical steel pin and through the first disc, the thrust washer and the second pin. The bearing element may further comprise a bolt for securing the second disc, the thrust washer and the first disc to the cylindrical steel pin.
The pin and thrust washer may rotate relative to the housing.
The housing may be fixed in position, and the pin and thrust washer may rotate.
The housing may be fixed to a supporting frame.
The cylindrical steel pin may be connected to a rotatable element.
A second end of the cylindrical steel pin may be provided with a screw thread which is fitted to the rotatable element.
There is provided agricultural machinery comprising: a supporting frame; a housing comprising a cylindrical opening, the housing being fixably attached to the supporting frame; an annular bearing fitted to the cylindrical opening within the housing; a cylindrical steel pin accommodated within the annular bearing, and having one end fixably attached to a rotating element; and a thrust washer accommodated with the annular bearing, fixably attached to another end the cylindrical steel pin.
There is provided a fixed rolling element bearing assembly comprising: a housing; an inner race for attaching to a rotating shaft; a cage and rolling element assembly positioned around the inner race; first and second positional locators for positioning the cage and rolling element assembly between inner edges thereof; a thrust washer adjacent an outer edge of either the first or second positional locator and fixably connected to the housing.
There is provided a hub bearing system comprising: a hub (housing) containing (at least one) void of revolution opening within its body; at least one solid of revolution bearing (with finite length) accommodated within the (at least one) void of revolution opening(s) of the hub; and a solid of revolution pin accommodated within the (at least one) solid of revolution bearing(s).
A solid of revolution bearing can be one of: (i) held so that it rotates with the hub relative to the pin (or even an integral part of the hub); (ii) held so that it rotates with the pin relative to the hub (or even an integral part of the pin); or (iii) merely accommodated in-between both hub and pin relative rotating surfaces as an independent body.
Voids of revolution and solids of revolution are respectively voids and solids created by rotating about the shared axis of rotation of both hub and pin.
Both hub and pin are designed to relatively rotate about their shared axis of rotation.
The bearing surfaces of hub and pin may be arranged such that they restrict bidirectional relative rotation of the hub and the pin about the remaining two axes as well as restricting bidirectional relative linear motion of the hub and pin along all three axes.
This is achieved via bearing surface(s) created between hub and body that are non-parallel to the hub and pin shared axis of rotation, capable of restricting the motions listed.
The bearing surfaces of hub and pin are arranged such that they restrict bidirectional relative rotation of the hub and the pin about the remaining two axes as well as restricting bidirectional relative linear motion of the hub and pin along two axes but only restricting unidirectionally relative linear motion of the hub and pin along the shared axis of rotation.
This is achieved via bearing surface(s) created between hub and body that are non-parallel to the hub and pin shared axis of rotation, capable of restricting the motions listed.
The bearing surfaces of hub and pin may be arranged such that they restrict bidirectional relative rotation of the hub and the pin about the remaining two axes as well as restricting bidirectional relative linear motion of the hub and pin along two axes yet does not restrict in either direction relative linear motion of hub and pin along the shared axis of rotation.
The hub bearing system may further comprise at least one axially-extruded (along the hub and pin shared axis of rotation) void within the hub void of revolution opening, creating at least one thrust face within the hub. This thrust face may have an additional bearing material fixed to it.
The hub bearing system may further comprise the at least one axially-extruded (along the hub and pin shared axis of rotation) solid attached to the pin, creating at least one thrust face attached to the pin. This thrust face may have an additional bearing material fixed to it.
The hub bearing system may further comprise at least one axially-extruded (along the hub and pin shared axis of rotation) void within the hub void of revolution opening, creating at least one thrust face within the hub. This thrust face may have an additional bearing material fixed to it. The hub bearing system may further comprise at least one axially-extruded (along the hub and pin shared axis of rotation) solid attached to the pin, creating at least one thrust face attached to the pin. This thrust face may have an additional bearing material fixed to it.
Relative linear motion of hub and pin along the shared axis of rotation of hub and pin may be restricted by the contact of hub and pin thrust faces in one direction.
Relative linear motion of hub and pin along the shared axis of rotation of hub and pin may also be restricted by the contact of hub and pin thrust faces in the opposite direction.
An independent thrust washer may be accommodated in-between the hub and pin thrust faces, yet may be free to rotate relatively independently of both hub and pin.
Either hub or pin thrust faces may have additional bearing material fixed to them.
The hub bearing system may further comprise at least one axially extruded (along the shared hub and pin axis of rotation) groove within the hub void of revolution opening, and the at least one thrust washer, wherein the at least one thrust washer is axially accommodated within the at least one axially-extruded groove. The thrust washer can be one of: (i) held so it rotates with the hub, relative to the pin (or an integral part of the hub); (ii) held so it rotates with the pin, relative to the hub (or an integral part of the pin; or (iii) merely accommodated between both hub and pin relative rotating surfaces
The hub bearing system my further comprise a first thrust body positioned axially along the solid of revolution pin (or connected to an end face of the pin) and a surface of the at least one thrust washer, restricting relative linear motion of hub and pin along the shared axis of relative rotation of hub and pin.
The hub bearing system may further comprise a second thrust body positioned axially along the solid of revolution pin (or connected to an end face of the pin or connected to the end face of the first thrust body) and an opposite surface (relative to the thrust washer surface above) of the at least one thrust washer, restricting relative linear motion of hub and pin along the shared axis of relative rotation of hub and pin, in the direction opposite.
The hub bearing system may further comprise a non-turn pin extending from a position in the solid of revolution pin and through first thrust body (if the first thrust body is connected to an end face of the pin) and through the second thrust body (if the second thrust body is connected to either an end face of the pin or an end face of the first thrust body). This is to ensure that pin and both thrust bodies are rotationally fixed relative to each other.
The non-turn pin does not pass through the thrust washer.
The hub bearing system may further comprise a bolt and washer for securing the first and/or second thrust bodies to the solid of revolution pin (where either or both thrust bodies are connected to an end face of the pin or the other thrust body).
The hub and thrust washer may rotate relative to the pin, and the pin may be fixed.
The pin may rotate relative to the hub and thrust washer, and the hub and thrust washer may be fixed.
The hub may be fixed to a supporting frame. The hub may be fixed to a rotatable element.
The solid of revolution pin may be connected to a rotatable element. The solid of revolution pin may be fixed to a supporting frame.
A second axial end of the solid of revolution pin (or an axial end of either thrust body) may be provided with a screw thread which is fitted to the rotatable element.
A second axial end of the solid of revolution pin (or an axial end of either thrust body) may be provided with a screw thread which is fitted to a supporting frame.
There is provided agricultural machinery comprising: a supporting frame; a housing (hub) comprising a void of revolution, the housing being fixably attached to the supporting frame; a solid of revolution bearing accommodated within the void of revolution of the housing; and a solid of revolution pin accommodated within the solid of revolution bearing, and having one end fixably attached to a rotatable element.
There is provided agricultural machinery comprising: a supporting frame; a rotatable element; a housing (hub) comprising a void of revolution, the housing being fixably attached to the rotatable element; a solid of revolution bearing accommodated within the void of revolution of the housing; and a solid of revolution pin accommodated within the solid of revolution bearing, and having one end fixably attached to the supporting frame.
There is provided agricultural machinery comprising a thrust washer accommodated within the solid of revolution bearing, fixably attached to another end of the solid of revolution pin.
The invention is described by way of example to the accompanying drawings in which:
The invention is now described with reference to examples and embodiments.
With reference to
The basic pin 10 is preferably a basic solid of revolution. The exemplary basic pin 10 comprises a cylindrical element having three distinct portions of different outer diameters. A first portion 2 having the smallest outer diameter is screw threaded. A second portion 4 has a middle outer diameter and a third portion 6 has the largest outer diameter. The portions 2 and 6 of the exemplary basic pin 10 are disposed at either end of the cylindrical pin, and the portion 4 in the middle, effectively joining the portions 2 and 6. The radial steps between the portions 4 and 6 and the portions 4 and 2 create a non-parallel (to the axis of rotation) radial surface along the pin. The radial step between the portions 4 and 6 is denoted by reference numeral 5.
The portion 6 has a radial end face 12, having an opening 8 for a hollow axial portion, which as will be described further below accommodates a retaining element. The face 12 is also provided with an off-centre or off-rotation axis hollow portion or recess 11 for a non-turn pin to be accommodated, as described further hereinbelow. The face 12 may contain a recess or a protrusion relative to the external surface of the portion 6 to aid alignment of components fitted later.
Also identified in
For assembly of the bearing, the basic pin 10 as shown in
With reference to
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In
The hub or housing 32 is exemplary, and other hubs or housings having different dimensions and configurations may be provided.
The hub 32 preferably comprises a solid of revolution with a void of revolution formed therein. The hub 32 is hollowed out and generally can be considered as containing a cavity or void. The void of the hub 32 has a first portion which is shaped to accommodate the basic pin 10 of
The void of the hub 32 also extends to cover any remaining part of portion 6 of the basic pin 10, but with this portion of the void in the hub 32 having a larger outer diameter such that there is an additional gap between the outer diameter of portion 6 of the basic pin 10, and an inner surface 38c of the void within the hub. This difference in outer diameters creates a radial gap in the hub void, between the outer surface of section 6 of the pin and the inner surface 36a, 36b of the hub.
Within this additional gap is provided the plain bearing 34, the edges of which are shown in
As can be seen from
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Next to this surface there is provided a first axial extrusion or groove 42 within the hub, which has a surface denoted by reference numeral 42a. This axial extrusion is thus preferably formed within the void of revolution of the hub 32. This axial extrusion exists to accommodate a thrust washer, the purpose of which will be discussed hereinafter.
There is also adjacent to the second axial extrusion 42 a further inner surface 47 of the void within the hub. As shown in
The first axial extrusion 42 extends to open within this second axial extrusion 46.
The exemplary hub 32 has a generally conical external shape, having a narrowest outer diameter at the point at which the portions 4 and 2 of the pin 10 extend from the hub, and having a largest outer diameter at the portion which encompasses the inner surface 47. This external diameter is sufficiently large to encompass axial extrusions or openings such as axial extrusion 48, which can be used for fitting the hub 32 to a piece of machinery in an implementation (or to a relative rotating external component).
As also shown in
Turning to
To achieve this axial restriction within axial extrusion 42 requires the thrust washer to axially traverse within the axial void bounded by axial surfaces 47, 44a, 46 and 44b, and then once axially adjacent axial extrusion 42 to radially move so that the further axial linear motion of the thrust washer relative to the hub is restricted by the radial surfaces of the axial extrusion 42. Note there has to be radial clearance between thrust washer and the axial surfaces 44a, 46 and 44b to allow this axial travel from hub end face to axial extrusion 42.
The thrust washer 42 has two anti-rotation lugs, or retaining portions, 43a and 43b. The exemplary thrust washer shown is not a 360° solid of revolution body generated by revolution about the axis of rotation, such that it is not an entire annular ring. The thrust washer 62 does not complete an annular ring, but terminates at the anti-rotation lugs 43a and 43b. These anti-rotation lugs extend into the axial extrusion bounded by axial surfaces 44a, 46 and 46b when the thrust washer is in situ, in order to restrict the relative angular motion of the thrust washer 62 relative to the hub 32, each lug restricting relative angular motion in one direction. Alternative designs may be provided in order to retain the thrust washer in place. The thrust washer does not have to be formed in the specific arrangement as shown, nor does the housing 32 have to be formed to have the specific arrangement to accommodate this specifically shaped thrust washer.
With reference to
With reference to
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This second thrust body element 72 operates to restrict the relative linear motion of the pin and hub in the opposite direction to that of the first thrust body element 52.
Hence via two thrust body elements and one thrust washer, axial relative motion of the hub 32 and the basic pin 5 is restricted.
It should be noted that both thrust body elements are provided with a radially off-set axial extrusion to accommodate the non-turn pin 22, which extends at least partly through the second thrust body element and fully through the first thrust body element, to ensure that both thrust body elements and the pin rotate together.
With regard to
A hexagonal head bolt (and a washer) is added to the arrangement. The hexagonal head bolt is represented by reference numeral 82, and the washer is represented by reference numeral 84. The axial void 8 within the basic pin 10 is preferably provided with a screw thread along at least a portion of its axial surface, and the hexagonal head bolt 82 is screwed into this screw thread, so as to secure the first 52 and second 72 thrust body elements to the basic pin 10, and enclose the non-turn pin 22 which ensures that the assembly 80 rotates together.
Referring to
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With this first embodiment there has been shown a cylindrical journal bearing which allows bidirectional relative rotation of the hub and pin about their shared axis of rotation. This bearing is also capable of restricting relative rotation about the other two perpendicular axes due to its finite length. Relative linear motion is also restricted about the two axes perpendicular to the shared axis of rotation of hub and pin. However relative linear motion of the hub and pin is not restricted by this bearing. Hence the use of the thrust washer axially restricting bidirectional relative linear motion of hub and pin along the shared axis of rotation. This may be direct contact of thrust-faces on hub and pin, or the use as shown in the exemplary first embodiment of an intermediary sliding element.
There is now described alternate second embodiment of a hub bearing system. This second embodiment utilises the same principles as the described first embodiment. These principles are:
If the void of revolution opening(s) and solid of revolution bearing(s) do not restrict relative axial linear motion of the hub and the pin (as well as restricting all the other previously listed relative motion restrictions required), then additional bearing(s) are introduced to perform this/these restriction(s) where necessary.
The second embodiment is a modification of the first embodiment, in as much as:
The second embodiment achieves the same result, but utilises two thrust washers, each of which is connected to one of the cylindrical bearings in opposed directions). Two thrust body thrust-faces are again employed. One thrust body thrust-face is an integral part of the pin, the other thrust body thrust-face is a washer that axially slides onto the pin to create the second thrust-face, resulting in the required relative linear motion restriction which is not facilitated by the use of cylindrical bearings alone.
There is shown in
Bush 132 is a hollow cylindrical portion having an outer surface 136, and an extended lip 140 at one end. Bush 134 is also a hollow cylinder having an outer surface 138, and an extended lip 142 at one end.
With reference to
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The two non-turn pins 146 and 148 are shown. These are shown as extending from the relative caps 142 and 144, through the extended lip of the relevant bush elements and into the body of the housing element 152. Reference numerals 160a, 160b represent portions of the bush element 132, being both the extended lip 140 and the outer portion 136. Reference numerals 162a, 162b represent portions of the bush element 134, being both the extended lip 142 and portions 138.
Also shown in
As shown in the cut-away of
The housing 152 of
The second embodiment illustrates a variation of the first embodiment, where cylindrical journal bearings are employed as in the first embodiment, but the ‘thrust washer’ principle is replaced via two ‘flange’ bearing elements (shown as an integral additional parts of the cylindrical journal bearings in the illustrated second embodiment), bi-directionally restricting the relative linear motion of hub and pin via thrust faces on hub and pin—these thrust faces are non-parallel to the shared axis of rotation of hub and pin, enabling this relative linear motion restriction.
The invention has been described with reference to particular examples, features of which may be combined. Not all described features are essential.