Field of application

[0001] The present invention relates to a joint group and a single-suspended-wheel steering system of a vehicle for agricultural use comprising said joint group.

State of the art

[0002] In mechanics, and in general, in mechanical interactions, transformation systems of the motion have long been known of in which the motion is converted from a linear movement to a rotary movement; among the various solutions are connecting rod-crank systems or systems with a jack which controls t he rotation of a shaft.

[0003] However, the components in it comprised in the mutual engagement, often as a result of geometric or mechanical problems, does not present a limited movement on a single axis; in fact, the mutual engagement between the various components is achieved by the use of spherical joints, which by definition allow the rotary movement with respect to its spherical end in the three axes .

[0004] The main drawback in the use of spherical joints is that of not allowing a simple and effective assessment and detection of the rotation, and -of the rotation angles, about the axes of the joint. Presentation of the- invention

[0005] The purpose of the present invention is to provide a joint group in which it is possible to detect the main angle of rotation of the joint, i.e., a joint group in which the above-mentioned drawback typical of the prior art is overcome.

[0006] Such purpose is achieved by a joint group made according to claim 1; such purpose is also achieved for example in a single-suspended-wheel steering system of a vehicle according to claim 13. The dependent claims describe further preferred embodiments.

Description of the drawings

[0007] The characteristics and advantages of the joint group , according to the present invention will be evident from the description given below, by way of a non- limiting example, according to the. appended drawings, wherein:

figure 1 shows a side view of a joint group of the present invention, according to a preferred embodiment; - figure la shows a cross-section view of the joint group in figure 1, along the cross-section plane V-V;

figure lb is a view from above of the joint group in figure 1;

figure 2 shows a perspective view in separate parts of the joint group in figure 1; figure 3 shows a perspective view of a single- suspended-wheel steering system comprising the joint group shown in the aforementioned drawings.

Detailed description

[0008] With reference to the appended drawings, reference numeral 1 globally denotes a joint group in its entirety according to a preferred embodiment.

[0009] Preferably, the joint group is suitable for operatively connecting a first . component and a second component. In particular, the joint group 1 is suitable to allow the movement of the first component with respect to the second component, wherein said movement is of the rotary type, preferably around an axis of rotation R-R. By means of the joint group 1 therefore the first component is suitable to rotate relative to the second component and / or vice versa.

[00010] It is to be noted that the present invention is not limited to the type of components connected to and from the joint group 1. Any component to which the joint group 1 is attachable to, is suitable to be operatively connected by this to another component, according to the description given below. For example, in one embodiment, the joint group 1 is operatively connected to a jack and to a shaft, in such .a way that the movement of the jack causes the rotary movement of said shaft. [00011] In a preferred embodiment, the joint group 1 according to the present invention finds application in a vehicle for agricultural use, for example a tractor. Preferably, it finds application in a single-suspended- wheel steering system 100 of the tractor, i.e. the support and control system of the rotation of a wheel assembly, or of a tyre. Preferably, the single-suspended- wheel steering system 100 is at the front of the vehicle for agricultural use. Preferably, the single-suspended- wheel steering system 100 is a drive wheel.

[00012] According to a preferred embodiment, the system 100 comprises a wheel-carrier 150 for the wheel group and at least one suspension arm 151 for the support and cushioning of the wheel group. The joint group 1 is therefore suitable to operatively connect said wheel carrier 150 to the suspension arm 151, according to the description below, respectively the first and the second component operatively connected by the joint group 1.

[00013] Preferably, the joint group 1 comprises a pin 10 that extends along a pivot axis P-P between a first end 11 and a second spherical end 12.

[00014] Preferably, the joint group 1 comprises a housing body 50 fixable to the second component and suitable to house the spherical end 12, according to the description below. In a preferred embodiment, the housing body 50 is provided with at least a fixing wall 505 on which the second component is suitable to be fixed, for example by means of screws-bolts.

[00015] According to a preferred embodiment, instead, the first end 11 is suitable to be fixed to the first component .

[00016] According to a preferred embodiment, the first end 11 is fixable to the first component which is, for example, screwed to it. Preferably, the first end 11 comprises a threaded cavity 111 in which a special locking screw 161 is screwable.

[00017] Preferably, the joint group 1 comprises a flange element 55 integrally connected to the first end 11, for example by means of a threaded coupling, for example being fitted on said first end 11 fixed by means of a special locking screw 161. Said flange element 55 comprises an assembly surface 555 to which the first component is suitable to be fixed.

[00018] According to a preferred embodiment, the joint group 1 comprises a rotation device 20 comprising . a central body 21 in which is fitted and integrally connected the second spherical end 12 of the pin 10 and rotation means 25 suitable to allow the free rotation of the central body 21 around the axis of rotation R-R.

[00019] In other words, the housing body 50 comprises a housing cavity 500 preferably axial symmetric, which extends along the axis of rotation R-R. In this manner, the joint group 1 in its entirety is substantially contained in the housing cavity 500; in fact, only a portion of the pin 10 extends outside said housing cavity 500, in particular the first end 11.

[00020] Preferably, the central body 21 comprises a ball housing 210 delimited by housing walls 210', in which the second spherical end 12 is received.

[00021] According to a preferred embodiment, the second spherical end 12 is connected to the central body 21 by means of a transverse pin 121 which extends along a transverse axis Y-Y perpendicular to the axis of rotation R-R and passing from the centre C of the second spherical end 12. The pin 121 engages said housing walls 210' so that the pin 10 is free to rotate around said transverse axis Y-Y. In other words the pin 121 prevents the second spherical end 12 from freely rotating around the centre C in all degrees of freedom.

[00022] According to a preferred embodiment, the central body 21 has two pin slots 215 radially opposite with respect to the axis of rotation R-R. Preferably, the pin slots 215 are made on the housing walls 210' and extend parallel to the axis of rotation R-R. In said pin slots 215 the ends of the transverse pin 121 are housed, free to move.

[00023] In other words, the two pin slots 215 allow movements of the pin 121 such as to recover, for example, shaking of the relative movement between first and second components and any assembly tolerances between the. components. It is to be noted that the angular movement of the pin 121 in the slots 215 is represented in figure la by the dotted lines.

[ 00024 ] In addition, preferably, the central body 21 comprises an abutment element 212 suitable to keep, the centre C fixed along the axis of rotation R-R. In other words, the central body 21 has inside it an abutment element 212 on which the second spherical end 12 acts, free to move the abutment element 212 has ^' in fact a concave shape such as to allow the housing and the support of a portion of the second spherical end 12. Preferably, the curvature of said concave portion has the same radius as the second spherical end 12; in other words its radius is equal to the distance from the centre C of the outer wall of the second spherical end 12.

[00025] According to a preferred embodiment, the abutment element 212 is in an anti-friction material, i.e. with a low friction coefficient, preferably, a material selected from the group of polymers or metals having a low friction coefficient or low-friction, such as bronze alloys.

[00026] According to a preferred embodiment, the rotation means 25 comprise one or more bearings 251, having the inner surface 251' operatively connected to the central body 21 and the outer surface 251" operatively connected to the component in which the rotation device 20 is housed.

[00027] In a preferred embodiment, the rotation means 25 comprise two tapered roller bearings 251 arranged in such a way that the available angles of the cones are opposite and facing the centre of the joint group 1 where the second spherical end 12 is preferably placed. Embodiments are however known in which the rotation means 25 comprise one or more ball or sliding bearings.

[00028] In other words, the rotation means 25 are suitable to manage both the axial loads and radial loads.

[00029] According to a preferred embodiment, the central body 21 consists of two main portions.

[00030] Preferably, the central body 21 comprises a first portion 21a and a second portion 21b suitable to engage each other along the axis of rotation R-R in such a way as to delimit the ball housing 210. In other words, along the vertical, the first portion 21a and second portion 21b are adapted to engage each other, for example by screwing to one another. Preferably, the first portion 21a and second portion 21b are flanged radially in such a way as to sandwich the rotation means 25 between the respective flanges.

[00031] According to a preferred embodiment, the joint group further comprises a rotation sensor device 30 suitable for ^' detecting the angle of rotation of the central body 21 around said rotation axis R-R; in other words, the rotation sensor device 30 is suitable to detect the angle of rotation of the second component.

[00032] Depending on the various embodiments, the rotation sensor device 30 is fixed to the housing body 50.

[00033] Preferably, the rotation sensor device 30 comprises a detection element 31 positioned on the axis of rotation R-R.

[00034] In a preferred embodiment, the rotation sensor device 30 comprises a flange 32 for fixing the rotation sensor device 30 to the housing body 50.

[00035] Preferably, the flange 32 has along ^' the rotation axis R-R, a detection aperture 320 through which the detection element 31 is inserted to interface with the central body 21.

[00036] In a preferred embodiment, the detection element 31 interfaces with the second portion 21b.

[00037] Preferably, the flange 32 has, along the axis of rotation R-R, a seat 321 for housing the detection element 31, wherein said seat 321 is in communication with the detection aperture 320.

[00038] According to a preferred embodiment, the detection element 31 is suitable for detecting angles of rotation around the axis of rotation R-R of the central body 21, starting from a zero position, up to ±90°, preferably up to ±60°.

[00039] Depending on the type of configuration therefore, the detection element 31 is suitable to detect a rotation of the central body 21, for example induced by the pin 10 through the pin 121, with respect to the flange 320. Conversely, in other embodiments, the central body 21 is kept in a fixed position by the pin 10, by means of the pin 121, and it is the housing body 50 and thus the flange 320 fixed to it which are rotated: the detection element 31 is suitable to detect the relative rotation of the central body 21 with respect to these.

[00040] In a preferred embodiment, the rotation sensor device 30 also comprises a realignment sleeve 300, suitable to recover any misalignments of the sensor with respect to the axis of rotation R-R, for example related to assembly tolerances. In other words, the detection element 31 is suitable to detect the relative movement of said sleeve 300 induced by the main body 21 to which the sleeve 300 is fixed.

[00041] In a preferred embodiment, the realignment sleeve 300 is made of an elastically yielding material, for example a polymeric rubber material.

[00042] Innovatively, the joint group of the present invention makes it possible to achieve the intended purpose of the invention, i.e. to provide a precise detection of the angle of relative rotation between two operatively connected components.

[00043] Advantageously, the joint group is suitable to perform the detection of the angle of rotation about the axis of rotation continuing to ensure the coupling with three degrees of freedom needed in these embodiments.

[00044] Moreover, advantageously, the detection is always reliable and correct in real time being taken with respect to the central body, without, instead, being conditioned by the movements of the rotary joint.

[00045] A further advantage is that of having a coupling group in which the three axes of movement are isolated from each other and thus the rotations around them are effectively measurable. Advantageously therefore the movement around one axis does not affect that around the other axes.

[00046] Yet a further advantage lies in the fact that the joint group is rigid and sturdy, and therefore suitable to be used in hostile and demanding environments such as those related to mechanical applications.

[00047] Moreover, advantageously, the joint group is not particularly cumbersome and can be fitted to a plurality of mutually different components.

[00048] Advantageously, the joint group is suitable to find application in various mechanical applications, such as on a single-suspended-wheel steering system.

[00049] Furthermore, the joint group is advantageously suitable in various mechanical applications in which two generic components must be placed in a relative rotary movement operatively connected to each other, in other words the joint group is suitable to replace the use of ball joints continuing to ensure the three degrees of freedom; advantageously, the joint group is also applicable ¹ in connecting rod-crank systems or is applicable to join a jack to a rotation shaft.

[00050] It is clear that a person skilled in the art may make modifications to the joint group so as to satisfy contingent requirements ,all contained within the scope of protection as defined by the following claims.