HUB ASSEMBLY FOR AN AGRICULTURAL IMPLEMENT AND ASSOCIATED AGRICULTURAL IMPLEMENT

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a hub assembly for an agricultural implement, more specifically for an implement that rolls on the ground such as a disc harrow. It also relates to an agricultural implement provided with such a hub assembly.

BACKGROUND ART

Independent disc stubble cultivators and soil tillage machines are commonly equipped with several dozens of discs, each supported by an independent hub assembly. Usually, each hub assembly comprises a hub housing provided with a through hole defining cylindrical cavity and a shoulder protruding radially inwards with respect to the through hole for receiving an outer race ring, which is press-fitted into the cylindrical cavity and abuts against the shoulder. The hub housing is provided with a flange protruding radially outwardly at one end of the hub housing for securing a disc harrow. A spacer may be pinched axially between the disc harrow and the outer race ring to locate the outer race ring in the axial direction. The spacer is a closed ring press-fitted into the cavity. As a result, the mounting process of the hub assembly necessitates tools for assembling the spacer with press-fit.

SUMMARY OF THE INVENTION

The invention aims to provide improved hub assembly which is easy to mount.

According to a first aspect of the invention, there is provided a hub assembly for an agricultural implement, comprising:

• a hub housing having an outer wall defining a mounting flange and an inner wall defining a through cavity;
• an outer race ring unit comprising one or more outer race rings press-fitted into the through cavity, the outer race ring unit defining a reference axis of the hub assembly and having a first axial end bearing against a shoulder of the inner wall of the hub housing inside the through cavity, and
• a semi-flexible open spacer ring radially elastically retained against the inner wall in the through cavity, the semi-flexible open spacer ring having an inner axial end bearing against a second axial end of the outer race ring unit opposite the first axial end and an outer axial end which is flush with, or protrudes from, a planar face of the mounting flange.

The force necessary to mount the semi-flexible open spacer ring into the through cavity is greatly reduced. The installation of the semi-flexible open spacer ring can be done by hand within seconds.

Preferably, wherein the inner wall has a cylindrical portion, the outer race ring unit is press-fitted into the cylindrical portion of the inner wall and the semi-flexible open spacer ring is radially elastically retained against the cylindrical portion of the inner wall. The semi-flexible open spacer ring is not retained in a groove of the inner wall.

According to one embodiment, the semi-flexible open spacer ring has a cylindrical outer face in contact with the inner wall of the hub housing. Preferably, the semi-flexible open spacer ring has quadrangular cross-section.

According to one embodiment, the mounting flange has one or more through holes parallel to the reference axis. The through holes are used to fasten the agricultural implement to the hub housing by means of mechanical fasteners such as bolts, screws, rivets or the like. The through holes can be cylindrical, with or without inner threads.

According to one embodiment, the mounting flange is provided with an annular groove opened axially for receiving an annular seal. The annular seal seals the interface between the flange of the hub housing and the agricultural implement.

According to one embodiment, the hub assembly is further provided with an inner race ring unit comprising one or more inner race rings, and one or more rows of rolling bodies between the inner race ring unit and the outer race ring unit, for guiding a rotation movement of the outer race ring unit relative to the inner race ring unit about the reference axis of the hub assembly. The rolling bodies can be balls, cylindrical or tapered rollers, and more generally any kind of rolling bodies that has an external surface of revolution.

According to a another aspect of the invention, there is provided an agricultural implement assembly comprising the hub assembly as described hereinbefore and an agricultural rotary implement, in particular a disc harrow, fixed to the flange of the hub housing, wherein the rotary implement bears axially against the outer end of the semi-flexible open spacer ring. Thus, the outer race ring unit is maintained axially between the shoulder at one axial end and the spacer ring and agricultural implement at the other.

According to an embodiment, the agricultural implement further comprises a support pin having an inner section inside the through cavity of the hub housing and a protruding section that protrudes axially outside the hub housing in a direction opposite the planar face, wherein the inner race ring unit is press-fitted onto the inner section of the support pin and bears axially against a shoulder of the support pin at one end of the inner section of the support pin opposite the protruding section.

According to one embodiment, the agricultural implement further comprises a support arm to which the support pin is fastened. Advantageously, the support arm bears axially directly or indirectly against the inner race ring unit. A spacer ring and/or a washer can be fitted on the support pin between the inner race ring unit and the support arm. The inner race ring unit is rigidly maintained axially between the shoulder of the support pin and the support arm.

The support pin can be fixed by any means to the support arm, preferably by releasable mechanical fasteners such as screws or bolts, to allow maintenance or replacement of the agricultural implement or of the hub assembly. Preferably, the protruding section of the support pin extends through a through hole of the support arm. A nut can be screwed onto a threaded end of the protruding end section of the support pin.

According to a preferred embodiment, the support arm is part of a harrow frame.

BRIEF DESCRIPTION OF THE FIGURES

Other advantages and features of the invention will then become more clearly apparent from the following description of a specific embodiment of the invention given as non-restrictive example only and represented in the accompanying drawings in which:

• figure 1 is an isometric view of a hub assembly for an agricultural implement according to an embodiment of the invention;
• figure 2 is a radial section of an agricultural implement provided with the hub assembly of figure 1.

Corresponding reference numerals refer to the same or corresponding parts in each of the figures.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the figures, a hub assembly 10 for an agricultural implement 12, e.g. a disc harrow, comprises a hub housing 14 having an outer wall 16 defining a mounting flange 18 and an inner wall 20 defining a through cavity 22.

The mounting flange 18 is preferably annular and has a planar face 24 that extends in a plane perpendicular to a reference axis 100 of the hub assembly 10. The mounting flange 18 has one or more threaded through holes 26 parallel to the reference axis 100 for mounting the agricultural implement 12 by means of screws or other mechanical fasteners 28, as illustrated in Figure 2. The mounting flange 18 may also be provided with an annular groove 30 opened axially for receiving an annular seal 32 that seals the interface between the mounting flange 18 and the agricultural implement 12.

The inner wall 20 of the hub housing 14 has a cylindrical portion 34 that extends from the planar face 24 of the flange 18 to a shoulder 36 inside the through cavity 22.

A rolling bearing 38 is received inside the through cavity 22 to allow rotation of the hub housing 14 and implement 12 about the reference axis 100. The rolling bearing 38 comprises an outer race ring unit 40 that consists of one or more outer race rings, which is press-fitted into the cylindrical portion 34 of the inner wall 20, such that a first axial end 41 of the outer race ring unit 40 bears against the shoulder 36 of the inner wall 20 of the hub housing 14 inside the through cavity 20.

The hub assembly 10 further comprises a semi-flexible open spacer ring 42 of quadrangular cross-section, with a cylindrical outer facewhich has a larger nominal diameter than the cylindrical portion 34 of the inner wall 20 and is elastically retained against the cylindrical portion 34 of the inner wall 20 in the through cavity 20. The spacer ring 42 has an inner axial end 44 that bears against a second axial end 46 of the outer race ring unit 42 opposite the first axial end 41, and an outer axial end 48 which is flush with, or slightly protrudes from, the planar face 24 of the mounting flange 18. The agricultural implement 12 fixed to the flange 18 of the hub housing 14 bears axially against the outer end 48 of the open spacer ring 42 to axially maintain the position of the open spacer ring 42 and of the outer race ring unit 40. As illustrated in figure 1, the open spacer ring 42 extends in the circumferential direction over an angle of more than 270°, preferably more 290°, and in one preferred embodiment more than 300°, and can easily be deformed elastically to temporally reduce its diameter, insert it into the through cavity 22 and snap it into place.

The rolling bearing 38 further comprises an inner race ring unit 50 comprising one or more inner race rings 51, and one or more rows of rolling bodies 52 between the inner race ring unit 50 and the outer race ring unit 40, for guiding a rotation movement of the outer race ring unit 40 relative to the inner race ring unit 50 about the reference axis 100 of the hub assembly 10.

The inner race ring unit 50 is press-fitted onto an inner section 54 of a support pin 56 and bears axially against a shoulder 58 at one end of the inner section 54 of the support pin 56. The support pin 56 has a protruding section 60 that protrudes axially outside the hub housing 14 in a direction opposite the planar face 24 and extends through a through hole 62 of a support arm 64, which can be a fixed or articulated part of an implement frame, e.g. a harrow frame. A nut 66 is screwed onto a threaded end of the protruding end section 60 of the support pin 56 to fasten the support pin 60 to the support arm 64. A washer 68 and a spacer ring 70 are mounted on the support pin 56 between the support arm 64 and the inner race ring unit 50. The washer 68 substantially closes the open space between the support pin 56 and the hub housing 14, without contacting the hub housing 14. Cassette seals 72 are mounted between the spacer ring 70 and the hub housing 14 and between the outer race ring unit 40 and inner race ring unit 50.