Device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle

Abstract

The device (1) for the transmission of motion between a driving machine and an equipment or in a special vehicle comprises: - a supporting body (2); - a pair of transmission joints (5) of the homokinetic ball joint type associated to a respective end of the support body (2); - an input shaft (6) connectable to a driving machine or to the engine of a special vehicle and connected to one of the transmission joints (5); - an output shaft (7) connectable to an appliance to be operated or to the wheels of a special vehicle and connected to the other of the transmission joints (5); - a linkage joint (8) of the universal joint type, housed internally to the supporting body (2) and adapted to kinematically connect the input shaft (6) to the output shaft (7); - a centering assembly (9) positioned between the linkage joint (8) and the shafts (6, 7).

Description

[0001] DEVICE FOR THE TRANSMISSION OF MOTION BETWEEN A DRIVING MACHINE AND A PIECE OF EQUIPMENT OR IN A SPECIAL VEHICLE

[0002] Technical Field

[0003] The present invention relates to a device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle.

[0004] Background Art

[0005] In several areas of mechanics, special mechanical components, known as transmission joints, are known to be used to transmit power and rotary motion from an input shaft, also known as a crankshaft, to an output shaft, also known as a driven shaft.

[0006] Transmission joints can be used to transmit motion between a driving machine and a piece of equipment to be driven.

[0007] Again, transmission joints can be used to transmit motion in special types of vehicles which, in the context of this disclosure, are referred to by the verbal phrase “special vehicles”.

[0008] In such a case, the transmission joints are inserted into the kinematic chain of special vehicles, placing between the engine of the special vehicle and the wheels of the same, thus enabling the transmission of the rotary motion from the engine to the wheels.

[0009] “Special vehicles”, with reference to this disclosure, are to be meant as special motor vehicles that are preferably used in agriculture and / or construction to carry out special works.

[0010] The following types of vehicles may fall under the definition of “special vehicles”: vehicles used for road maintenance and public works; agricultural tractors and self-propelled agricultural equipment; construction machinery; earthmoving equipment; snowplow; all-terrain vehicles. The aforementioned vehicles are generally moved in very tight maneuvering spaces that require being able to steer with very small turning radii.

[0011] In mechanical transmissions, rotating shafts that are kinematically connected through transmission joints can be aligned or can be incident and form a joint angle of varying amplitude.

[0012] A special type of device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle are the universal joints of the cardan type.

[0013] As is well known, a universal joint consists of a spider, on which two forks are articulated, and which allows the forks to rotate the one with respect to the other according to two substantially orthogonal axes.

[0014] One of the two forks is connected to the crankshaft while the other of the two forks is connected to the driven shaft.

[0015] In the case of universal joints, the instantaneous transmission ratio, meant as the ratio of the instantaneous speeds of the driving fork and of the driven fork, is not constant over time but has a periodic sinusoidal pattern.

[0016] Consequently, even in the case where the speed of the driving fork is uniform, the speed of the driven fork is variable instant by instant, that is, the driven fork rotates with accelerated motion.

[0017] In particular, the aforementioned variation in speed occurs periodically several times for each rotation of the shafts thus generating, as an inevitable consequence, strong impulses on the crankshaft and on the driven shaft, which result in vibration and noise.

[0018] This drawback is compounded by an additional problem from which universal joints suffer, namely the occurrence, on the crankshaft and on the driven shaft, of bending moments that also vary in amplitude depending on the joint angle.

[0019] These stresses, called secondary torques, further increase the impulses, vibrations and noises generated, eventually further exacerbating the drawbacks just described.

[0020] To at least partly fix these drawbacks, the use of special rotary device for the transmission of motions, known as homokinetic ball joints, is known. Notoriously, a homokinetic ball joint consists of a bell-shaped body which is connected to the crankshaft and rotates together with the latter, and a central core, which is mounted inside the bell-shaped body and connected to the driven shaft. In some cases, depending on industrial applications, provision can be made to connect the bell-shaped body to the driven shaft and the central core to the crankshaft.

[0021] In addition, the homokinetic ball joints comprise a plurality of balls which are arranged between the bell-shaped body and the central core and which enable the transmission of motion between the aforementioned components.

[0022] In detail, in the case where the shafts connected to the homokinetic joint are misaligned, the balls begin to rotate thus allowing the transmission of the rotary motion from the bell-shaped body to the central core.

[0023] Thanks to the presence of grooves, cut on both the bell-shaped body and on the central core, the balls can rotate and slide within the grooves themselves, thus enabling the transmission of motion even if the output shaft and the input shaft are incident.

[0024] The homokinetic joints also comprise a cage whose job is to hold the balls, thus preventing them from falling out of the homokinetic joint due to the forces they are subjected to during the transmission of motion between the crankshaft and the driven shaft.

[0025] Homokinetic joints, regardless of the amplitude of the joint angle, are able to maintain a constant transmission ratio over time, i.e., the ratio of the angular speed of the crankshaft to the angular speed of the driven shaft.

[0026] It seems clear that homokinetic joints do not suffer from the drawbacks suffered by universal joints and related to a non-uniform transmission ratio between the rotational speeds of the crankshaft and the rotational speed of the driven shaft. However, the use of homokinetic ball joints has some drawbacks that are mainly related to the fact that they do not allow motion to be transmitted between two shafts arranged according to a high joint angle.

[0027] In this regard, it is worth noting that homokinetic joints of known type can operate with a maximum joint angle of about 50°. Related to this, it is necessary to point out that if the joint angle increases beyond a certain value, the bell-shaped body may collide with the shaft connected to the central core, damaging both the bell-shaped body and the shaft itself

[0028] Again, as a result of the high operating angle, considerable heat can be generated due to rubbing of the components which can damage the homokinetic joint.

[0029] Additionally, if high joint angles are reached, the balls are subjected to high forces which must be counteracted by the retaining cage which may be damaged accordingly.

[0030] In addition, if the joint angle is very high, the transmissible torque from the homokinetic joint must be kept low, and similarly, if high torque needs to be transmitted, the amplitude from the joint angle must be kept low.

[0031] Again, in cases where it is necessary to maintain a high joint angle, without sacrificing the ability to transmit high torque, it is necessary to reduce the friction between the components by having significant lubrication of the components.

[0032] In some industrial applications, a compromise can be made between the width of the joint angle and the torque to be transmitted so as to ensure an appreciable useful life of the homokinetic joint.

[0033] However, there are industrial applications in which the homokinetic joints of known type cannot be used because both high joint angles and high transmission torque are required.

[0034] This is, for example, the case with special vehicles wherein, in the case of tight steering, very high joint angles are reached which are poorly tolerated by the homokinetic joints of known type which, in detail, can break.

[0035] This makes the use of homokinetic joints of the known type very inconvenient in the case of special vehicles.

[0036] By way of example only, it is possible to point out that in the agricultural / forestry field it is necessary to ensure the transmission of motion between rotating shafts arranged according to joint angles as wide as 80°, in order to ensure steering maneuverability for all types of equipment used.

[0037] To fix at least partly the aforementioned drawbacks suffered by the homokinetic joints of known type, the use of special device for the transmission of motions is known consisting of two universal joints connected in series.

[0038] Such special joints allow motion to be transmitted even between incident shafts arranged at high joint angles but, nevertheless, they suffer from some drawbacks mainly related to the fact that by connecting two universal joints, optimal centering cannot be achieved.

[0039] This is compounded by the fact that double universal joint transmission devices can become significantly damaged when placed in unfavorable environments, particularly dusty and / or humid environments, resulting in low reliability over time.

[0040] Again, double universal joint transmission devices are generally very bulky and require frequent maintenance work.

[0041] These aspects make the use of double universal joint transmission devices very inconvenient.

[0042] Description of the Invention

[0043] The main aim of the present invention is to devise a device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle which allows rotary motion and power to be transmitted even when the rotating shafts are mutually inclined by high joint angles.

[0044] Within the scope of this aim, one object of the present invention is to devise a device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle which allows rotary motion and power to be transmitted between two incident shafts according to a joint angle greater than 50°.

[0045] Still, another object of the present invention is to devise a device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle which allows high torques to be transmitted even in the case of high joint angles between rotating shafts.

[0046] A further object of the present invention is to devise a device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle which may have a very long service life while requiring little maintenance. Another object of the present invention is to devise a device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle which can overcome the aforementioned drawbacks of the prior art within the framework of a simple, rational, easy and effective to use as well as inexpensive solution.

[0047] The aforementioned objects are achieved by this device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle having the characteristics of claim 1.

[0048] Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle, illustrated by way of an indicative, yet nonlimiting example, in the accompanying tables of drawings in which:

[0049] Figure 1 is an axonometric view of a device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle according to the invention;

[0050] Figure 2 is an axonometric, partly exploded view of the device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle according to the invention;

[0051] Figure 3 is an axonometric, partly exploded view of some components of the device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle according to the invention;

[0052] Figure 4 is an axonometric, partly exploded view of some components of the device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle according to the invention;

[0053] Figures 5, 6 and 7 are cross-sectional views of the device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle according to the invention in three different configurations of use.

[0054] Embodiments of the Invention

[0055] With particular reference to these figures, reference numeral 1 globally denotes a device for the transmission of motion between a driving machine and a piece of equipment or in a special vehicle.

[0056] The device 1 according to the invention comprises: at least one supporting body 2 having a substantially elongated conformation, substantially hollow and provided with a first end 3 and with a second end 4; a pair of transmission joints 5 of the homokinetic ball joint type, one of the transmission joints 5 being associated with the first end 3 and the other of the transmission joints 5 being associated with the second end 4; at least one input shaft 6, connectable to a driving machine or to the engine of a special vehicle and connected to one of the transmission joints 5, the input shaft 6 extending longitudinally along an input axis A; at least one output shaft 7, connectable to an appliance to be operated or to the wheels of a special vehicle and connected to the other of the transmission joints 5, the output shaft 7 extending longitudinally along an output axis B, the input axis A and the output axis B being mutually inclined by a joint angle a of variable amplitude; at least one linkage joint 8 of the universal joint type, housed internally to the supporting body 2, adapted to kinematically connect the input shaft 6 to the output shaft 7 and to allow for their mutual positioning as the amplitude of the joint angle a changes; at least one centering assembly 9 positioned between the linkage joint 8 and the input shaft 6 and between the linkage joint 8 and the output shaft 7 and adapted to keep the linkage joint 8 in a centered position between the first end 3 and the second end 4 as the amplitude of the joint angle a changes.

[0057] The device 1 can be used to transmit rotary motion between a driving machine, which is connected to the input shaft 6, and an appliance to be operated, which is connected to the output shaft 7.

[0058] For example, the driving machine may be of the type of an agricultural machine and the equipment may be of the type of a piece of equipment of the agricultural type that is operated by the driving force transmitted thereto by the agricultural machine by means of the device 1. Again, the device 1 can be inserted into the kinematic chain of a special vehicle to transmit rotary motion between the engine of the special vehicle and the wheels of the latter.

[0059] In this particular case, the input shaft 6 is connected to a crankshaft connected to the engine of the special vehicle and the output shaft is connected to the wheels of the special vehicle itself

[0060] As previously described, within the scope of this disclosure by the verbal phrase “special vehicle”, particular motor vehicles are to be meant that are preferably used in the agricultural and / or construction fields to carry out special works.

[0061] The following types of vehicles may fall under the definition of “special vehicles”: vehicles used for road maintenance and public works; agricultural tractors and self-propelled agricultural equipment; construction machinery; earthmoving equipment; snowplow; all-terrain vehicles.

[0062] The aforementioned vehicles are generally moved in very tight maneuvering spaces that require being able to steer with very small radii of curvature.

[0063] With particular reference to the embodiment shown in the figures, the supporting body 2 has a substantially tubular conformation.

[0064] The first end 3 and the second end 4 are arranged aligned along the axis of longitudinal development of the supporting body 2.

[0065] With reference to the preferred embodiment shown in the figures, the first end 3 is the one positioned at the input shaft 6 and the second end 4 is positioned at the output shaft 7.

[0066] As can be seen from Figure 3, each of the transmission joints 5 comprises: at least one central core 10 mounted on one of either the input shaft 6 or the output shaft 7; at least one bell-shaped body 11 associated with one end 3, 4 of the supporting body 2 and developing around a respective central core 10; a plurality of ball-shaped bodies 12 positioned between the central core 10 and the bell-shaped body 11 and adapted to transfer the motion between the bell-shaped body 11 and the central core 10.

[0067] Specifically, the transmission joints 5 are homokinetic ball joints of the fixed type.

[0068] Again, each transmission joint 5 comprises a clamping element 26 placed between the central core 10 and the input shaft 6 or the output shaft 7 to which it is connected and adapted to prevent the input shaft 6 or the output shaft 7 from slipping off the respective central core 10.

[0069] Preferably, the clamping element 26 has a substantially annular conformation, with open ends, and is made of substantially elastic material.

[0070] In actual facts, the clamping element 26 is of the type of a seeger.

[0071] The bell-shaped body 11 and the central core 10 comprise a plurality of grooves 13 wherein the ball-shaped bodies 12 are adapted to slide and roll.

[0072] For pure representational simplicity, Figure 3 shows the transmission joint 5 associated with the input shaft 6.

[0073] Due to the presence of the grooves 13, it is possible to transmit motion between the central core 10 and the respective bell-shaped body 11 even when they are not aligned, that is, when the central core 10 is rotated with respect to the respective bell-shaped body 11.

[0074] In this particular condition, the ball-shaped bodies 12 can rotate and shift within the grooves 13 thus enabling the transmission of the rotary motion between the central core 10 and the bell-shaped body 11.

[0075] Such a condition, as will be shown below, occurs e.g. when the input shaft 6 and the output shaft 7 are no longer aligned but arranged in an incidental maimer.

[0076] Conveniently, each of the transmission joints 5 comprises at least one cage element 14 associated with the central core 10 and adapted to hold the ball-shaped bodies 12 associated with the relevant central core 10.

[0077] In detail, the cage element 14 is adapted to counteract the forces to which the ballshaped bodies 12 are subjected as a result of setting the central core 10 in rotation. Again, the device 1 comprises a pair of protective caps 15, each of which is associated with a respective transmission joint 5, at the bell-shaped body 11, and is arranged around the shaft 6, 7, associated with the same transmission joint 5. The protective caps 15 are adapted to protect the transmission joints 5 from being hit by objects placed outside the device 1 and / or from dust and / or dirt.

[0078] Usefully, the protective caps 15 are made of elastically deformable material in order to allow the rotation of the shaft 6, 7 and of the central core 10 with respect to the bell-shaped body 11 with which it is associated.

[0079] Again and with particular reference to the preferred embodiment shown in the figures, the protective caps 15 have a substantially bellows-like conformation in order to be able to be elastically compressed during the rotation of the central cores 10 with respect to their respective bell-shaped bodies 11.

[0080] These aspects will be explained in detail later.

[0081] As a result of the input shaft 6 being set into rotation, which occurs as a result of the transmission of rotary motion and power by the driving machine or motor of the special vehicle, the central core 10 connected to the input shaft 6, i.e., placed at the first end 3, begins to rotate.

[0082] Through the ball-shaped bodies 12, the rotary motion is transmitted from the central core 10, connected to the input shaft 6, to the bell-shaped body 11, associated with the first end 3.

[0083] Through the supporting body 2, the rotary motion is transmitted from the bellshaped body 11 associated with the first end 3 to the bell-shaped body 11 associated with the second end 4, i.e., positioned at the output shaft 7.

[0084] Thanks to the ball-shaped bodies 12, it is possible to transmit the rotary motion from the bell-shaped body 11 associated with the second end 4 to the relevant central core 10, that is, to the central core 10 connected to the output shaft 7.

[0085] As a result of this, the rotary motion is transmitted from the central core 10 located at the second end 4 to the output shaft 7 and from there to the appliance connected thereto or to the wheels of the special vehicle.

[0086] As a result of the mutual positioning between the driving machine and the appliance or between the crankshaft exiting the special vehicle’s engine and the driven shaft entering the special vehicle’s wheels, it is possible that the inclination of the input shaft 6 with respect to the output shaft 7 may change, thus generating a change in the amplitude of the joint angle a.

[0087] In detail, the input shaft 6 and the output shaft 7 may vary their positions between a condition of mutual alignment, wherein the amplitude of the joint angle a is substantially 0°, and a condition of incidence, wherein the amplitude of the joint angle a is greater than 0°.

[0088] Figure 5 shows a first configuration of using the device 1, wherein the input shaft 6 and the output shaft 7 are substantially aligned and the joint angle a is substantially equal to 0°.

[0089] In this particular configuration of use, the input shaft 6 and the output shaft 7 are substantially parallel to the axis of longitudinal development of the supporting body 2.

[0090] Figures 6 and 7 show two configurations of use of the device 1 that differ from each other and from the configuration of use in Figure 5 wherein the input shaft 6 and the output shaft 7 are incident and the joint angle a has an amplitude greater than 0°.

[0091] In detail, Figure 7 shows a particular configuration of the device 1 wherein the joint angle a has an amplitude substantially equal to 80°, corresponding to the maximum inclination of operation according to which the shafts 6, 7 can be positioned.

[0092] In this regard, it should be pointed out that under particular conditions it is possible to place the input shaft 6 and the output shaft 7 in a condition of mutual inclination wherein the joint angle a has an amplitude substantially equal to 90°, corresponding to a condition of maximum inclination.

[0093] This particular condition of inclination is preferably not reached under normal conditions of use of the device 1, due to the possible damage that may be done to the device’s components.

[0094] In particular, the joint angle a can be increased to an amplitude of 90° only under special conditions such as, e.g., assembly sequences or inspections.

[0095] Figure 6 shows a particular configuration of the device 1, which is intermediate between the configuration in Figure 5 and the configuration in Figure 7, wherein the joint angle a has an amplitude substantially equal to 45°.

[0096] With regard to this, it should be pointed out that it is possible to position the device 1 in infinite intermediate configurations between the one shown in Figure 5 and the one shown in Figure 7, besides the one shown in Figure 6, wherein the amplitude of the joint angle a is of between 0° and 80°.

[0097] When the input shaft 6 and the output shaft 7 are mutually positioned according to a joint angle a of amplitude greater than 0°, the central core 10 associated with the input shaft 6 rotates together with the latter, thus rotating with respect to the bell-shaped body 11 associated with the first end 3.

[0098] Likewise, the central core 10 associated with the output shaft 7 rotates together with the latter, thus rotating with respect to the bell-shaped body 11 associated with the second end 4.

[0099] The bell-shaped bodies 11 maintain their position substantially unchanged as they are connected to the supporting body 2.

[0100] As a result of the rotation of the central cores 10 with respect to the corresponding bell-shaped bodies 11, the protective caps 15 are compressed in order to allow the above-mentioned rotary motion.

[0101] The protective caps 15 are not shown in Figures 5 and 6 and 7 for pure representational simplicity.

[0102] The following disclosure will explain in more detail how the linkage joint 8 and the centering assembly 9 operate synergistically in conjunction with each other in order to enable the mutual positioning between the input shaft 6 and the output shaft 7 as the amplitude of the joint angle a changes.

[0103] Specifically, it is shown that the linkage joint 8 and the centering assembly 9 allow the incidence of the input axis A of the input shaft 6 and of the output axis B of the output shaft 7 to be maintained during operation as the amplitude of the joint angle a changes.

[0104] Specifically, the point of incidence between the two axes A and B remains centered between the first end 3 and the second end 4 as the amplitude of the joint angle a changes.

[0105] As can be seen in detail in Figure 4, the linkage joint 8 comprises: at least one cruciform body 16 defining at least a first axis of rotation C and at least a second axis of rotation D substantially orthogonal to each other; at least a first fork-shaped body 17 associated with the input shaft 6 and associated with the cruciform body 16 in a rotatable maimer around the first axis of rotation C; at least a second fork-shaped body 18 associated with the output shaft 7 and associated with the cruciform body 16 in a rotatable manner around the second axis of rotation D.

[0106] At least one of either the first fork-shaped body 17 or the second fork-shaped body 18 is adapted to rotate around the cruciform body 16 as a result of the change of the amplitude of the joint angle a.

[0107] Usefully, the centering assembly 9 comprises: at least a first sliding pin 19 associated with the first fork-shaped body 17 and adapted to slide internally to the input shaft 6, along the input axis A, as a result of the rotation of the first fork-shaped body 17 around the first axis of rotation C; at least a second sliding pin 20 associated with the second fork-shaped body 18 and adapted to slide internally to the output shaft 7, along the output axis B, as a result of the rotation of the second fork-shaped body 18 around the second axis of rotation D.

[0108] Advantageously, the input shaft 6 internally comprises at least a first sliding seat 21 developing along the input axis A.

[0109] The first sliding pin 19 is associated with the first sliding seat 21 in a sliding manner.

[0110] Usefully, the output shaft 7 internally comprises at least a second sliding seat 22 developing along the output axis B.

[0111] The second sliding pin 20 is associated with the second sliding seat 22 in a sliding manner.

[0112] The linkage joint 8 performs the centering function with respect to the two transmission joints 5 connected thereto by means of the input shaft 6 and the output shaft 7. The linkage joint 8, as can be seen from the figures, is arranged in the exact centerline of the supporting body 2 both when the joint angle a has amplitude equal to 0° and when the joint angle a has amplitude greater than 0°.

[0113] In other words, the linkage joint 8 is kept at the same distance from the ends 3, 4, regardless of the width of the joint angle a.

[0114] This special positioning of the linkage joint 8 is made possible by the centering assembly 9 and, in particular, by the ability to make the first sliding pin 19 slide within the input shaft 6 and the second sliding pin 20 within the output shaft 7. In detail, the sliding pins 19, 20 slide in the proximity of the central cores 10.

[0115] The aforementioned sliding is essential to enable the articulation of the input shaft 6 to the output shaft 7 and of the two transmission joints 5.

[0116] The sliding of the sliding pins 19, 20 is at the minimum level when the joint angle a has an amplitude substantially equal to 0° and is at the maximum level when the amplitude of the joint angle a is maximum, as in Figure 7.

[0117] The sliding function is followed hand in hand by the idle rotation function and it is not binding.

[0118] It is therefore irrelevant if the linkage joint 8 cannot transmit power consistently over time as the amplitude of the joint angle a changes because it does not perform the function of transmitting motion but merely represents a joint center of the device 1.

[0119] It may happen that for the first degrees of articulation, that is, in the case where the amplitude of the joint angle a is a little more than 0°, the linkage joint 8 rotates together with the input shaft 6 and with the output shaft 7.

[0120] Subsequently, i.e., as the amplitude of the joint angle a increases, it may happen that the linkage joint 8 stops rotating but continues to perform, together with the centering assembly 9, the function of a centering device by further angling itself when still.

[0121] The ability for the linkage joint 8 to rotate together with the input shaft and with the output shaft 7, or to stand still while the latter rotate, is ensured by the sliding pins 19, 20 sliding within the shafts 6, 7.

[0122] According to the preferred embodiment shown in the figures, the centering assembly 9 comprises elastic retaining means 23, 24 adapted to counteract at least one of either the sliding of the first sliding pin 19 within the input shaft 6 or the sliding of the second sliding pin 20 within the output shaft 7.

[0123] Preferably, the elastic retaining means 23, 24 comprise: at least a first spring element 23, associated with the input shaft 6 and with the first sliding pin 19 and arranged within the first sliding seat 21; at least a second spring element 24, associated with the output shaft 7 and with the second sliding pin 20 and arranged within the second sliding seat 22. Advantageously, the first sliding seat 21 defines at least a first abutment surface substantially orthogonal to the input axis A.

[0124] The first spring element 23 is located between the first abutment surface and the first sliding pin 19.

[0125] Usefully, the second sliding seat 22 defines at least a second abutment surface substantially orthogonal to the output axis B.

[0126] The second spring element 24 is located between the second abutment surface and the second sliding pin 20.

[0127] Usefully, the first spring element 23 and the second spring element 24 are substantially identical to each other.

[0128] In other words, the first spring element 23 and the second spring element 24 are made of the same construction material, have substantially the same diameter, the same length and the same pitch.

[0129] The first spring element 23 and the second spring element 24 operate in conjunction with the sliding pins 19, 20 in keeping the linkage joint 8 in a centered position with respect to the ends 3, 4.

[0130] In fact, since the spring elements 23, 24 are substantially identical, they react substantially the same to any external stress.

[0131] If the linkage joint 8 were not to be positioned centered with respect to the ends 3, 4, of the supporting body 2, one of the spring elements 23, 24 would be more loaded than the other spring element 23, 24 and would push on the corresponding sliding pin 19, 20 until the two spring elements 23, 24 are equally stressed.

[0132] In actual facts, due to the synergistic combination of the action of the sliding pins 19, 20 and of the spring elements 23, 24, the linkage joint 8 is always positioned in a balanced maimer between the ends 3, 4.

[0133] However, it should be noted that alternative embodiments of the device 1 are provided wherein the centering assembly 9 does not comprise the elastic retaining means 23, 24.

[0134] In such a case, the centering action of the linkage joint 8 is solely enacted by the combined action of the first sliding pin 19 and of the second sliding pin 20 sliding within the input shaft 6 and the output shaft 7, respectively.

[0135] In light of these considerations, it is possible to state that the device 1 according to the invention allows the input shaft 6 and the output shaft 7 to be positioned according to the desired joint angle a by dividing the magnitude of the joint angle a between the two transmission joints 5.

[0136] In other words, the central core 10 of the transmission joint 5 connected to the input shaft 6 is positioned inclined with respect to the corresponding bell-shaped body 11 according to a first angle of amplitude substantially equal to half the joint angle a.

[0137] Similarly, the central core 10 of the transmission joint 5 connected to the output shaft 7 is positioned inclined with respect to the corresponding bell-shaped body 11 according to a second angle of amplitude substantially equal to half the joint angle a.

[0138] In this way, it is possible to incline the input shaft 6 and the output shaft 7 according to high joint angles a, even of amplitude on the order of 80°, since the overall amplitude is divided into two angles of half amplitude.

[0139] For example, if the joint angle a has an amplitude of 45°, using a single homokinetic ball joint, the job takes place in a range of stresses and frictions close to the operating limit of the single homokinetic joint.

[0140] Differently, if the joint angle a has an amplitude of 45°, the device 1 allows each transmission joint 5 of the homokinetic type to work at an angle of half amplitude of approximately 22.5°, that is, a value abundantly within the operating limits of the homokinetic joint of known type.

[0141] It is therefore evident how the use of the device 1 is convenient in all those ranges where rotary motion with a large joint angle a needs to be transmitted, reaching a value of 80° for the operations, e.g. of steering turns in maneuvering by feeding a towed piece of equipment.

[0142] Again, the device 1 according to the invention allows for decreasing the radii of curvature in special vehicles or can be used as a replacement for conventional universal joints to be able to work under conditions of steep inclination between the driving machine and equipment.

[0143] Dividing the amplitude of the joint angle a in half between the transmission joints 5 also makes it possible to lower, for the same joint angle a, the stresses, friction and heat operating on each transmission joint 5 by 50% at all times compared with the case where there is a single homokinetic ball joint.

[0144] This aspect makes it possible to increase the rotational speed of the input shaft 6 and of the output shaft 7, allowing higher power values to be transmitted than if a single homokinetic joint were used.

[0145] Advantageously, the supporting body 2 defines at least one housing compartment 25 adapted to house the linkage joint 8 and at least one lubricating fluid of the transmission joints 5, of the linkage joint 8 and of the centering assembly 9.

[0146] In actual facts, the lubrication of the linkage joint 8 and of the centering assembly 9 is provided by the same lubricant as the homokinetic transmission joints 5, thus not requiring a dedicated lubrication system.

[0147] Again, the special conformation of the supporting body 2 allows accommodating a much larger amount of lubricating fluid than can be accommodated in the transmission devices of known type.

[0148] The possibility of having a much larger amount of lubricating fluid than is the case in known technology makes it possible to increase the level of lubrication of the components of the device 1, thereby reducing the frequency with which maintenance work on the device 1 itself must be provided.

[0149] It has in practice been ascertained that the described invention achieves the intended objects, and in particular, the fact is emphasized that providing for the presence of two homokinetic joints connected by means of a universal joint and a centering assembly makes it possible to transmit the rotary motion and power even when the rotating shafts are mutually inclined by high joint angles.

[0150] In detail, it is possible to state that the device for the transmission of motion according to the invention allows operating even at joint angles of more than 50° amplitude. Additionally, the device for the transmission of motion according to the invention makes it possible to reduce the radius of curvature in the case of special vehicles. Furthermore, it is possible to say that the device for the transmission of motion according to the invention allows high torques to be transmitted even in the case of high joint angles between the rotating shafts, and allows maintenance work to be reduced, while providing a particularly long service life.

[0151] Additionally, the device for the transmission of motion according to the invention has a substantially compact conformation and, in particular, has a narrower width than the solutions of known type.

[0152] In addition, the device for the transmission of motion according to the invention has a lower weight than the solutions of known type.

[0153] Such expedients make the device covered by the invention easily adaptable to being mounted in confined spaces and facilitate the movement thereof, even if to be carried out frequently.

Claims

CLAIMS1) Device (1) for the transmission of motion between a driving machine and an equipment or in a special vehicle, characterized by the fact that it comprises: at least one supporting body (2) having a substantially elongated conformation, substantially hollow and provided with a first end (3) and with a second end (4); a pair of transmission joints (5) of the homokinetic ball joint type, one of said transmission joints (5) being associated with said first end (3) and the other of said transmission joints (5) being associated with said second end (4); at least one input shaft (6), connectable to a driving machine or to the engine of a special vehicle and connected to one of said transmission joints (5), said input shaft (6) extending longitudinally along an input axis (A); at least one output shaft (7), connectable to an appliance to be operated or to the wheels of a special vehicle and connected to the other of said transmission joints (5), said output shaft (7) extending longitudinally along an output axis (B), said input axis (A) and said output axis (B) being mutually inclined by a joint angle (a) of variable amplitude; at least one linkage joint (8) of the universal joint type, housed internally to said supporting body (2), adapted to kinematically connect said input shaft (6) to said output shaft (7) and to allow for their mutual positioning as the amplitude of said joint angle (a) changes; at least one centering assembly (9) positioned between said linkage joint (8) and said input shaft (6) and between said linkage joint (8) and said output shaft (7) and adapted to keep said linkage joint (8) in a centered position between said first end (3) and said second end (4) as the amplitude of said joint angle (a) changes.2) Device (1) according to claim 1, characterized by the fact that said linkage joint (8) comprises: at least one cruciform body (16) defining at least a first axis of rotation (C) and at least a second axis of rotation (D) substantially orthogonal to each other;at least a first fork-shaped body (17) associated with said input shaft (6) and associated with said cruciform body (16) in a rotatable maimer around said first axis of rotation (C); at least a second fork-shaped body (18) associated with said output shaft (7) and associated with said cruciform body (16) in a rotatable manner around said second axis of rotation (D); wherein at least one of either said first fork-shaped body (17) or said second forkshaped body (18) is adapted to rotate around said cruciform body (16) as a result of the variation from the amplitude of said joint angle (a).3) Device (1) according to one or more of the preceding claims, characterized by the fact that said centering assembly (9) comprises: at least a first sliding pin (19) associated with said first fork-shaped body (17) and adapted to slide internally to said input shaft (6), along said input axis (A), as a result of the rotation of said first fork-shaped body (17) around said first axis of rotation (C); at least a second sliding pin (20) associated with said second fork-shaped body (18) and adapted to slide internally to said output shaft (7), along said output axis (B), as a result of the rotation of said second fork-shaped body (18) around said second axis of rotation (D).4) Device (1) according to one or more of the preceding claims, characterized by the fact that: said output shaft (7) internally comprises at least a second sliding seat (22) developing along said output axis (B), said second sliding pin (20) being associated with said second sliding seat (22) in a sliding manner.5) Device (1) according to one or more of the preceding claims, characterized by the fact that said centering assembly (9) comprises elastic retaining means (23, 24) adapted to counteract at least one of either the sliding of said first sliding pin (19) within said input shaft (6) or the sliding of said second sliding pin (20) within said output shaft (7).6) Device (1) according to one or more of the preceding claims, characterized by the fact that said elastic retaining means (23, 24) comprise:at least a first spring element (23), associated with said input shaft (6) and with said first sliding pin (19) and arranged within said first sliding seat (21); at least a second spring element (24), associated with said output shaft (7) and with said second sliding pin (20) and arranged within said second sliding seat (22).7) Device (1) according to one or more of the preceding claims, characterized by the fact that said first spring element (23) and said second spring element (24) are substantially identical to each other.8) Device (1) according to one or more of the preceding claims, characterized by the fact that: said first sliding seat (21) defines at least a first abutment surface substantially orthogonal to said input axis (A), said first spring element (23) being located between said first abutment surface and said first sliding pin (19); said second sliding seat (22) defines at least a second abutment surface substantially orthogonal to said output axis (B), said second spring element (24) being located between said second abutment surface and said second sliding pin (20).9) Device (1) according to one or more of the preceding claims, characterized by the fact that each of said transmission joints (5) comprises: at least one central core (10) mounted on one of either said input shaft (6) or said output shaft (7); at least one bell-shaped body (11) associated with one said end (3, 4) of said supporting body (2) and developing around a respective said central core (10); a plurality of ball-shaped bodies (12) positioned between said central core (10) and said bell-shaped body (11) and adapted to transfer the motion between said bell-shaped body (11) and said central core (10), said bellshaped body (11) and said central core (10) comprising a plurality of grooves (13) wherein said ball-shaped bodies (12) are adapted to slide and roll.10) Device (1) according to one or more of the preceding claims, characterized by the fact that said supporting body (2) has a substantially tubular conformationand defines at least one housing compartment (25) adapted to house said linkage joint (8) and at least one lubricating fluid of said transmission joints (5), of said linkage joint (8) and of said centering assembly (9).

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