ASSEMBLY COMPRISING THE CV JOINT

Description

Technical Field

The present invention finds application in the field of the operating machines and relates to an articulated CV joint for power transmissions for connecting a driving machine to an operating machine.

State of the art

The driving machines for uses in agriculture, such as tractors and the like, are generally provided with a power take-off (PTO) for the removable connection of an operating machine, such as threshing machines, fertilizer spreaders and the like, selected in function of the specific work to be performed.

In particular, the connection between the driving machine and the operating machine is realized by means of a transmission system comprising a first and a second connection joint designed to be respectively associated with the PTO of the driving machine and to a coupling element of the operating machine.

The two joints are mutually connected by means of a transmission shaft that transmits the rotational movement from the first joint to the second joint, which in turn will be connected through a suitable linkage to the work unit of the operating machine to provide it with the necessary work motion.

Examples of such a system for power transmission are disclosed in US 2012/028723, US 3,385,388, DE 19803614 and in WO 2008/037006, wherein the two end joints are connected by a transmission shaft with telescopic structure.

The main drawback, common to the known solutions, is represented by the difficulty in adjusting the angle between the connecting shafts of the joints without reducing the transmitted power and avoiding the occurrence of excessive vibrations.

In particular, the known jointing systems for operating machines allow to realize connections between the junction shaft within very limited ranges of mutual angulations.

From US 2,584,648 a universal joint is known which comprises a head stably associated to a transmission shaft and which is provided with a spherical seat for a spherical joint body provided with a driven shaft movable within the spherical seat.

The two spherical elements are connected by a conical gear that allows the mutual inclination of the shafts with a large adjustable angle of inclination . However, this joint limits the rotation of the driven shaft also in a plane transverse to the transmission shaft, thus limiting the possibilities of connection between the driving machine and the operating machine, not granting sufficient flexibility in operation to the junction.

Scope of the invention

An object of the present invention is to overcome the above drawbacks, realizing an articulated CV joint for power transmissions which is particularly efficient and relatively cost-effective.

A particular object is to realize an articulated CV joint for power transmissions which allows to vary the angle of inclination of the connecting shaft to the PTO of the driving machine or operating machine within a very high range of values.

Still another object is to provide an articulated CV joint for power transmissions which has high power transmission rate.

Still another object is to provide an articulated CV joint for power transmission which reduces the vibrations transmitted from the driving machine to the operating machine, containing the wear.

A further object is to provide an articulated CV joint for power transmissions which allows complete rotations in the space of the connecting shaft to allow the transmission of power even when the driving shaft and the driven shaft are not axially aligned.

Not last object is to provide an articulated CV joint for power transmission which is particularly compact and safe, with reduced overall dimensions and provided with a high ease of assembly and disassembly on the machine to be connected.

These objects, as well as others which will appear more clear hereinafter, are obtained by an articulated CV joint for power transmissions designed to connect a driving machine equipped with a PTO to an operating machine and which, according to claim 1, comprises a head having first means for connection to one of the driving machine and the operating machine and a containment shell defining thereinside an at least partially spherical seat, a spherical body movably housed in said seat and having second means for connection to the other between the driving machine and the operating machine, a first gear element solidal with said spherical body and provided with a first conical toothing, a second gear element solidal to said shell and provided with a second conical toothing adapted to engage with the conical toothing of said first gear element to allow the rotation of said spherical body in said seat around a first axis of rotation .

The second gear element comprises a pair of rollers mutually solidal and rotatable about a common second axis of rotation orthogonal to said first axis of rotation and having respective second conical toothed surfaces defining respective portions of said second conical toothing and adapted to engage simultaneously said first conical toothing to allow the rotation of said spherical body around said first axis and the rotation of said first axis of rotation around said second axis solidal with said spherical body.

Thanks to this combination of features, the joint will allow to rotate the spherical body and the related second connection means not only in a single plane of rotation but in the whole space, allowing to obtain a high angle in the connection between the driving shaft of the driving machine and the driven shaft of the operating machine.

By this way it will possible to compensate the movements and oscillations of the joint outside the vertical symmetry plane so that the power transmission rate will not be affected and the vibration transmitted from the driving machine to the operating machine will be reduced.

According to a further aspect of the invention a jointing assembly is provided for connecting a driving machine and an operating machine which assembly, according to claim 17, comprises a pair of CV joints according to the invention provided with corresponding first connecting means for respectively connecting to the PTO of the driving machine and to the operating machine and a driving shaft having opposite ends adapted to be removably connected to the second connecting means of respective transmission joints for transmitting the motion from the PTO to the operating machine. This embodiment will allow to obtain an angle between the two joints having a value in a range considerably wider than the known solutions, as the two joints may be angled relative to the driving shaft with a 90° angle.

Advantageous embodiments of the joint and of the assembly are provided according to the dependent claims.

Brief disclosures of the drawings

Further features and advantages of the invention will become more apparent in light of the detailed description of some preferred but not exclusive embodiments of an articulated CV joint for power transmission according to the invention, wherein such embodiments are shown by way of a not limiting example with the aid of the annexed drawings wherein:

FIG. 1 is a front view of a joint assembly comprising a pair of joints according to the invention;

FIG. 2 is a sectional view of a joint according to the invention in a first preferred embodiment;

FIG. 3 is a perspective view of a joint of the invention in a second preferred embodiment;

FIG. 4 is a front view of the joint of Fig. 3;

FIG. 5 is a sectional view of the joint of Fig. 4 sectioned along the V- V plane;

FIG. 6 is a sectional view of the joint of Fig. 4 sectioned along the VI- VI plane; FIG. 7 is an exploded perspective view of a particular of the joint of Fig. 3.

Best modes of carrying out the invention

Fig. 1 shows a jointing assembly for the transmission of power from a driving machine to an operating machine comprising a pair of joints according to the present invention. This assembly, generally indicated by 1, will find application in any industrial field and in particular in the agricultural field to connect the PTO of a tractor or similar driving machine to any operating machine of common use, such as, but not limited to, a threshing machine, fertilizer spreaders, lawn mower or other machine for working soil and/or crop.

The assembly and the joint may also be applied in industrial machines, in the nautical sector, for example for boats such as fishing boats, pleasure boats and motorboats, and in all the applications wherein moving mechanical members are provided which require special transmissions to transfer power from a driving member to a driven or user member.

The assembly 1 essentially comprises a first joint 2 adapted to be connected, in a known manner, to a PTO of a driving machine and a second joint 2' adapted to be connected in turn to a suitable coupling element of an operating machine designed to receive the motion and to be actuated from the driving machine through the PTO, both machines and related parts not being illustrated in the attached figures as of known type.

The two joints 2, 2' are mutually connected in a removable manner to the opposite ends of a transmission shaft 3 to transmit the motion from the PTO to the operating machine. For sake of simplicity, since the two joints 2, 2' will be substantially similar to each other, in the following we will refer only to the joint 2, intending that everything will be referred to the joint 2 will be found in a substantially identical and technically equivalent manner also in the other joint 2'.

In its most general embodiment, the joint 2 comprises a head 4 having first means 5 for connection to one of the driving machine and the operating machine and a containment shell 6 defining thereinside an at least partially spherical seat 7 for housing a spherical body 8 movable in the seat 7 and having second connecting means 9 to the other between the driving machine and the operating machine.

The spherical body 8 is solidal with a first gear element 10 provided with a first conical toothing 11.

In turn, the containment shell 6 comprises a second gear element 12 provided with a second conical toothing 13 adapted to mesh with the first gear toothing 11 of the first gear element 10 to allow the rotation of the spherical body 8 inside the seat 7 around a first axis of rotation X.

The second gear element 12 comprises a pair of rollers 14, 15 mutually solidal and rotatable about a common second axis of rotation Y orthogonal to the first axis of rotation X.

Each roller 14, 15 has a respective second conical toothed surface 13', 12" that defines a portion of the second conical toothing 13.

Furthermore, the two second toothed surfaces 13', 13" are adapted to mesh simultaneously with the first conical toothing 11 to allow rotation of the spherical body 8 about the first axis X and at the same time the rotation of the first axis X about the second axis Y integrally with the spherical body 8, so that the same can be spatially oriented.

The first gear element 10 may preferably be made of one piece with the spherical body 8, so as to improve the reliability of the joint and to grant high efficiency in power transmission. Alternatively, the first gear element 10 may be anchored in a removable manner to the spherical body 8 so as to be possibly substituted in case of breakage or excessive wear.

Fig. 2 shows in section a first preferred embodiment of the CV joint 2, wherein the first gear element 10 is defined by a pair of first conical toothed surfaces 11 ', 11" formed in the material of the spherical body 8 and each of which defines a respective portion of the first conical toothing 11.

The first conical toothed surfaces 11', 11" are arranged in diametrically opposite positions with respect to the first axis of rotation X symmetrically with respect to a plane π passing through the first axis X and orthogonal to the second axis Y and each of them will be adapted to mesh with a corresponding second conical toothed surface 13', 13".

According to a not shown variant, the first gear element 10 may instead comprise a pair of toothed wheels rigidly attached to the spherical body 8, possibly in a removable manner, and each of which will have an outer surface comprising a respective first toothed conical surface 11 ' , 11" .

In the shown embodiment, each roller 14, 15 comprises a respective pin 16, 17 associated with a guide bearing 18, 19, with tapered roller bearings or ball bearings to be freely adjustable and allow the angle of the spherical body 8 to be adjusted.

The first connecting means 5 comprise a female coupling element 20, shown in Fig. 1, adapted to mate with a corresponding male element of the PTO of the driving or operating machine, not shown.

It is however understood that the coupling element 20 may also be shaped as a male element to connect with a counter- shaped female element of the machine, as well as the first connecting means 5 may be selected among the common mechanical connection means, without particular limitations.

The second connection means 9 comprise, in turn, a driven shaft 21 which extends from the spherical body 8 along a third axis Z orthogonal to the second axis of rotation Y. The driven shaft 21 will preferably be integral with the spherical body 8, possibly made in one piece, and will be designed to engage in a special cavity, not visible in the figures, realized in the corresponding end of the transmission shaft 3.

To promote the proper transmission of power between the driven shaft 21 and the transmission shaft 3, the respective contact surfaces will be provided with axial grooves and/or recesses 22 complementary shaped.

The head 4 is formed by two mutually joined half-shells 6', 6" and each of which has a semispherical seat adapted to receive a portion of the spherical body 8.

The shell 6 will also be provided with anti-friction means 23 associated with the inner surface thereof to allow the use of the joint for a high number of cycles without the need to provide for its continuous lubrication.

In particular, the inner surface of the spherical seat 7 may be provided with bushings or anti-friction rings in a low friction material.

Fig. 3 and Fig. 4 show a second preferred embodiment of the joint 2, which comprises a head 4 having an outer shell 6 provided with a flange 24 solidal with the first connecting means 5 to the driving or operating machine.

Even in this case, the first connecting means 5 comprise a female coupling element 20 defined by a tapered projection 25 extending from the flange 24 and which is provided with a peripherally grooved inner passage 26 to mate to the means of connection of the machine for which the joint 2 is designed. The shell 6 defines thereinside a spherical seat 7 for housing the spherical body 8 provided with the driven shaft 21 adapted to be connected to the transmission shaft 3. As shown in Fig. 5, the first gear element 10 is defined by a single conical gear wheel solidal with the spherical body 8 and which may be made either of one piece therewith or anchored in a stable and possibly removable manner.

In each case the gear wheel 10 may rotate about a first axis of rotation X integrally with the spherical body 8.

The toothed wheel 10 is also provided with an outer surface defining the first conical toothing 11 for simultaneously meshing with the second conical surface 13', 13" of the rollers 14, 15.

These latter, more clearly visible in Fig. 6, comprise each a cylindrical body 27, 28 rotatable on respective bearing means 29, 30 about a second axis of rotation Y.

Each roller 14, 15 is provided with a respective second conical toothed surface 13', 13" which extends peripherally to the respective cylindrical body 27, 28 with a perimeter smaller than the whole perimeter thereof, so that a part of the peripheral surface of the cylindrical body 27, 28 is lacking in teeth 13', 13" .

The two toothed rollers 14, 15 are made solidal with each other by means of a passing through pin 31 having ends 3 , 31" anchored in a fixed and possibly removable manner to the head 4 and which extends along the second axis of rotation Y, orthogonally to the driven shaft 21. The two rollers 14, 15 will be suitably keyed on the passing through pin 31 by the respective bearing means 29, 30.

Thus, the passing-through pin 31 will be solidal with the head 4, and then locked in the movements, while the spherical body 8 may rotate with a large degree of freedom both in a rotation plane π' parallel to the extension axis Y of the pin 31 and in plane π" orthogonal thereto, allowing the driven shaft 21 to achieve high angles of inclination with respect to the conical projection, with values up to 90°.

Finally, Fig. 7 shows a detail of the head 4: in particular it is possible to observe the guide rings 32, for example bushings, adapted to be interposed between the spherical body 8 and the housing 7 to reduce friction during the rotation.

The same figure also shows more clearly that the coupling element 20 comprises a locking tang 33 provided with a biasing spring 34 adapted to be operated manually to enable the locking and unlocking of the first connecting means 5 from the driving or operating machine and make easy the operations of connection and removal of the joint 2 from the machine. From the foregoing it is evident that the invention achieves the intended objects and in particular that of making available a CV joint which allows to transmit the power from a driving machine to an operating machine with high transmission rates, reducing vibration and wear.

The joint and the assembly according to the invention are susceptible of numerous modifications and variations, all falling within the inventive concept expressed in the appended claims.

All the details may be replaced with other technically equivalent elements and the materials may be different depending on needs, without departing from the scope of protection of the present invention. Also the dimensions of the various components do not represent a limit for the present invention and they may vary depending on the uses for which the joint and the assembly are designed.

Even if the joint and the assembly have been disclosed with particular reference to the annexed figures, reference numbers in the description and in the claims are used to improve the intelligence of the invention and do not constitute any limitation to the claimed scope of protection.