Variable track wheel and associated systems and methods

Abstract

A variable track wheel comprises a rim suitable for receiving a tire, and a disc through which said wheel is mountable on a hub, said disc being removably secured by fastenings to a connecting member provided in said rim, said connecting member projecting towards a rotation axis of said wheel, said wheel further comprising a plurality of spacers interposed between an annular perimeter zone of said disc and said connecting member of said rim, said disc and said rim being mountable in a plurality of reciprocal axial positions and in a plurality of reciprocal orientations to obtain a variation in the track of said wheel, said wheel further comprising at least one centering device for mutual positioning of said disc and of said rim said centering device comprising a hole and a pin said hole or said pin being provided in said connecting member or in said disc said centering device further comprising a coupling element so conformed as to cooperate with said hole and with said pin for reciprocally coupling said pin and said hole.

Claims

1. A variable track wheel comprising: a. a rim configured to receive a tire, the rim comprising a connecting member projecting toward the rotational axis of the wheel; b. a disc through which the wheel is mountable to a hub; c. a plurality of spacers disposed between the connecting member and the disc; and d. at least one centering device comprising; i. an opening in the connecting member; ii. a pin; iii. a coupling element; iv. a first portion defining a cavity to receive the pin, and v. a second portion comprising a stem for insertion into the opening, and wherein: a. the coupling element is constructed and arranged for reciprocal coupling of the pin and the opening; b. the disc is mountable to the rim in a plurality of positions; and c. the first portion further comprises a first arresting surface for contacting the disc and a second arresting surface for contacting the connecting member.

2. The variable track wheel of claim 1, further comprising a second centering device.

3. The variable track wheel of claim 2, wherein the second centering device comprises a pin of a diameter different than the diameter of the pin of the first centering device.

4. The variable track wheel of claim 3, wherein the second centering device comprises an opening of a different diameter than diameter of the opening of the first centering device.

5. A variable track wheel comprising: a. a disc; b. a rim; c. a plurality of spacers; and d. a pair of centering devices, each centering device comprising: i. an opening; ii. a pin; and iii. a coupling element, the coupling element comprising: a. a first portion defining a cavity; and b. a second portion defining a stem, and wherein: a. the at least one centering device is constructed and arranged to mount the disc and the rim such that the disc and rim are substantially coaxial; b. the disc and rim are connected via a plurality of bolts; c. the coupling element, the pin, and the opening are constructed and arranged to couple with one another; d. the each of the pair of centering devices is arranged in an intermediate zone between two consecutive bolts; e. the pair of centering devices are diametrically opposite one another; and f. the pin of a first centering device has a first diameter and the pin of a second centering device has a second diameter.

6. The variable track wheel of claim 5, wherein the disc may be mounted on the rim in a plurality of configurations.

7. The variable track wheel of claim 6, wherein the coupling element is constructed and arranged for repeated mounting of the disc to the rim.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention can be better comprised and implemented with reference to the attached drawings, which illustrate one embodiment thereof by way of non-limiting example, in which:

(2) FIG. 1 is a front view of a variable track wheel;

(3) FIG. 2 is an enlarged cross section taken along the plane II-II in FIG. 1;

(4) FIG. 3 is an enlarged cross section taken along the plane III-III in FIG. 1;

(5) FIG. 4 is an enlarged cross section taken along the plane IV-IV in FIG. 1;

(6) FIG. 5 is an enlarged view of the section in FIG. 3;

(7) FIG. 6 shows fragmentary and shrunk cross sections of the wheel in FIG. 1 corresponding to axial positions that are different from one another of the wheel and of a hub.

DETAILED DESCRIPTION

(8) FIGS. 1 and 2 show a variable track wheel 1, comprising a rim 2 that is suitable for receiving a tire, which is not shown, and a disc 3 through which the wheel 1 is mountable on a hub, which is also shown.

(9) The rim 2 comprises a connecting member 4, that projects from an internal circumferential surface 5 of the rim 2 to a rotation axis X of the wheel 1.

(10) The connecting member 4 comprises a circumferentially continuous singular annular element, which is fixed to the internal circumferential surface 5 for example by welding, in particular angular welding, indicated by W in FIGS. 1 and 2.

(11) In one alternative embodiment that is not shown, instead of a circumferentially continuous singular annular element, the connecting member 4 can comprise a plurality of circumferentially equidistant lobes.

(12) The connecting member 4 is substantially flat, i.e. extends parallel to a central diametral plane of the rim 2and thus of the wheel 1, of line M in FIG. 2, at a preset distance K from the latter.

(13) The disc 3 comprises a flat central region 30 in which a central opening 31 is provided that is arranged for receiving a portion of the hub. In the flat central region 30 a plurality of peripheral openings 32 are also provided that are angularly equidistant from one another and are arranged around the central circular opening 31, to mount the disc 3, and thus the wheel 1, on the hub, by means of removable connecting means such as, for example, bolts. The disc 3 further comprises a shaped region 33, for example of conical shape, which can include a first conical portion 34 and a second conical portion 35, wherein the first conical portion 34 has an angle at the vertex of the cone corresponding thereto that is greater than the angle at the vertex of the cone corresponding to the second conical portion 35. The disc 3 further comprises a flange region 36 of annular and substantially flat shape, arranged for facing the connecting member 4.

(14) Between the disc 3 and the connecting member 4 spacers 15 are interposed. The disc 3 is removably secured to the connecting member 4 by fastenings, in particular bolts 6, each bolt 6 comprising a screw 6a and a nut 6b. One or more washers 7 can be associated with the bolt 6 in the known manner. Each bolt 6 is received in a passage 12 provided in the connecting member 4 and in a fixing hole 13 provided in the disc 3, in particular in the flange region 36. Each bolt 6 is then received in a through hole 14 of the respective spacer 15, which is interposed between the connecting member 4 and the disc 3 at each passage 12 and each fixing hole 13.

(15) In the embodiment shown, on the connecting member 4 six passages 12 are provided, and respectively on the disc 3 six fixing holes 13 are provided. The passages 12 and the fixing holes 13 are angularly equidistant. In the embodiment shown, six spacers 15 are therefore provided.

(16) The spacers 15 have a set thickness S, by means of which it is possible to obtain a plurality of tracks that are different from one another according to the position and orientation of the disc 3 with respect to the rim 2 and of the rim 2 with respect to the hub.

(17) The wheel 1 comprises one centering device for mutual positioning of the disc 3 and of the rim 2.

(18) In particular, the wheel 1 comprises of pair of centering devices 8, 9 for mutual positioning of the disc 3 of the rim 2.

(19) The pair of centering devices 8, 9 comprises a first centering device 8 and a second centering device 9, which are in particular diametrically opposite one another.

(20) Each centering device 8, 9 is arranged in a respectively intermediate zone between two consecutive bolts 6.

(21) The first centering device 8 and a second centering device 9 are in particular arranged substantially at the same distance from the rotation axis (X).

(22) Subsequently, the common elements of the first centering device 8 and of the second centering device 9 are indicated by the same reference numbers.

(23) With reference to FIG. 5, each centering device 8, 9 comprises a hole 10 and a pin 11, the hole 10 being provided in the connecting member 4 and the pin 11 being mounted on the disc 3.

(24) The pin 11 is mounted with forced coupling or interference in an opening 16 of the disc 3. In particular, the pin 11 comprises a central, for example knurled, zone 17, intended for being in contact with walls of the opening 16. The pin 11 further comprises a first end 18 protruding from the disc 3 to the connecting member 4. The pin 11 can further comprise a second end 19, opposite the first end 18, protruding from a face of the disc 3 opposite the face from which the first end 18 protrudes. The first end 18 and the second end 19, which are both cylindrical in shape, have diameters that are substantially the same as one another. Hereinafter, when reference is made to the dimensions, and in particular to the diameter, of the pin 11, the dimensions, and in particular the diameter, of one of the protruding ends of the pin 11 is meant, namely of the first end 18 or of the second end 19.

(25) The fact that the first end 18 and the second end 19 protrude from faces of the disc 3 that are opposite one another enables the same pin 11 to be used for centering between disc 3 and rim 2 also in the configuration in which the disc 3 is rotated by 180 with respect to the central diametral plane M of the rim 2, as will be disclosed below.

(26) Each centering device 8, 9 further comprises a coupling element 21 cooperating with the hole 10 and with the pin 11 for reciprocally coupling the pin 11 and the hole 10.

(27) The coupling element 21 comprises a body provided with a first portion 23, for example of cylindrical shape.

(28) The first portion 23 is provided with a cavity 25, arranged for receiving in a shapingly coupled manner the first end 18, or the second end 19, of the pin 11. The cavity 25 extends centrally to the first portion 23.

(29) The first portion 23 is interposed between the connecting member 4 and the disc 3. The first portion 23 is provided with a first arresting surface 26 and with a second arresting surface 27 intended for contacting respectively the connecting member 4 and the disc 3.

(30) Further, the first portion 23 compensates the distance between the disc 3 and the connecting member 4 set by the spacers 15. Thus the first portion 23 has a longitudinal extent D that is substantially the same as the thickness S of the spacer 15.

(31) The body of the coupling element 21 further comprises a second portion 24, which projects from the first portion 23 so as to form a stem. In particular, the stem 24 projects from the first arresting surface 26, centrally thereto.

(32) The second portion or stem 24 is so conformed as to be received in a shapingly coupled manner in the hole 10 of the connecting member 4. The stem 24 is housed in the hole 10 with free coupling.

(33) The coupling element 21 enables the dimensions of the pin 11 to be disconnected from those of the hole 10 and vice versa.

(34) In fact, the difference in dimensions, in particular in diameter, that may be present between the pin 11 and the hole 10 is compensated by the coupling element 21.

(35) Thus the coupling element 21 enables only the disc or only the rim of a variable track wheel to be replaced without it being necessary to implement mechanical machinings on the disc and/or on the rim to be coupled to maintain the centering device effective. In other words, the coupling element acts as an adapter, which enables the pin to be compatible with the dimensions of the hole.

(36) If, for example, in the case of replacement of the rim or of the disc, the pin on the disc has too small a diameter compared with the diameter of the hole on the connecting member, the centering device does not operate, inasmuch as the excessive play between pin and hole does not permit precise coupling and thus sufficiently precise alignment of the axis of the rim and of the axis of the disc. In this case, the coupling element 21 will be conformed as to increase the reduced dimensions of the pin, such as to make the coupling between pin and hole of the centering device more precise.

(37) In the absence of the coupling element 21 that is specifically shaped for adapting to the dimensions of the pin 11, it would be necessary to remove the pin 11 from the forced coupling with the opening 16, widen this opening 16 and mount therein a new pin of larger dimensions that are compatible with the hole 10; alternatively it would be necessary to widen the hole 10 on the connecting member 4 or provide a new hole 10. Such operations might not be easily performable on the place in which the disc or the rim is replaced, with the risk of damaging the disc or the connecting member and making the centering device ineffective. Further, such operations could modify the weight of the disc and/or of the rim, thus causing the wheel to be no longer balanced.

(38) Similarly, if, for example, in the event of replacement of the rim or of the disc, the pin on the disc has a diameter that is greater than the diameter of the hole on the connecting member, the centering device might not be reused. In this case, it is sufficient to provide a coupling element that is specifically shaped to house the pin, for example the cavity 25 will have a diameter that is such as to house in a shapingly coupled manner the pin 11 of greater dimensions, whereas the stem 24 will have substantially the same dimensions as the hole 10.

(39) The coupling element 21 will thus be shaped in such a manner as to adapt to the dimensions of the hole 10 and to the dimensions of the pin 11 and in this manner adapt that hole 10 to that pin 11.

(40) In other words, instead of machining mechanically the spare parts or the parts on which the latter are mounted, it is possible to provide a certain range of coupling elements that differ from one another through the dimensions of the opening and of the stem to reuse the coupling device in the event of replacement. Such coupling elements enable the parts of the centering device to be adapted that are arranged respectively on the disc and on the rim. Owing to the coupling element, it is possible to choose a centering device in which the hole has different dimensions from the pin.

(41) In particular, the two centering devices 8, 9 can differ from one another by the respective dimensions of the hole or of the pin.

(42) In the embodiment illustrated in FIGS. 3 and 4, the first centering device 8 (FIG. 3) comprises a hole 10a of diameter L1 and the second centering device 9 (FIG. 4) comprises a hole 10b of diameter L2, wherein L1 and L2 are different from one another. The first centering device 8 thus comprises a first coupling element 21a provided with a stem 24a of a diameter that is such as to be housed in the hole 10a with free coupling. In other words, the diameter of the stem 24a is substantially the same as the diameter L1 or the hole 10a, less the coupling tolerance. Similarly, the second centering device 9 comprises a second coupling element 21b having a stem 24b of a diameter that is such as to be housed in the hole 10b with free coupling. In other words, the diameter of the stem 24b is substantially the same as the diameter L2 of the hole 10b, less the coupling tolerance. In this embodiment, the pin of the first centering device 8 and the pin of the second centering device 9 are the same as one another and these pins are indicated by the same reference number 11. Consequently, also the cavity 25 has the same dimensions on the two coupling elements 21a and 21b.

(43) In one embodiment that is not shown, the hole 10 can be provided on the disc 3 and the pin 11 on the connecting member 4. In this embodiment, the coupling element 21 is arranged rotated by 180 around a diametral plane of the rim with respect to the arrangement shown in FIG. 4 of the coupling element 20, i.e. the stem 24 is to the right of the cavity 25, not to the left, as shown in FIG. 4, and both stem 24 and cavity 25 will extend from left to right, and not from right to left as in FIG. 4.

(44) The centering devices 8, 9 are made during manufacture of the wheel 1.

(45) The disc 3 and the rim 2 are arranged substantially concentrically in a mask. Naturally, the manufacturing tolerances of the passage 12 on the connecting member 4 of the fixing hole 13 on the disc 3, and of the through hole 14 on the spacer 15 are such as to enable the position of the disc 3 to be adjusted in relation to the rim 2 in such a manner as to be able to align together the passages 12, the fixing holes 13 and the through hole 14 before the bolts 6 are tightened and the substantially concentric position of the disc 3 and rim 2 is fixed.

(46) In the substantially concentric position of the disc 3 and of the rim 2, the holes 10, or 10a and 10b are made respectively on the connecting member 4 and the openings 16, or 16a and 16b, on the disc 3.

(47) Subsequently, the bolts 6 are loosened and the disc 3 and the rim 2 are again moved away, such that the pins 11 can be mounted on the disc 3. The coupling element 21, or 21a and 21b, is associated with the corresponding pin 11. By again repositioning the disc 3 and the rim 2 on the mark in the substantially concentric position, the coupling element 21, or 21a and 21b, is now inserted into the hole 10, or 10a and 10b, and the first portion 23 is interposed between the disc 3 and the rim 2. The bolts 6 are tightened and the mask is removed.

(48) At this point the wheel 1 is ready for being subjected to balancing and marking.

(49) Marking the rim at the highor positive value point of the first harmonic of the wheelis known, which first harmonic is defined as the assembly of the rim and of the discand marking the wheel at the lowor negativevalue point of the first harmonic of the wheel. By mounting the wheel on the rim in such a manner that the position of the high value of the wheel substantially coincides with the position of the low value of the wheel, compensation is obtained of the geometrical manufacturing errors and of the distribution of the masses of the wheel and of the tire, which are one of the causes of vibrations in the vehicle. In this manner, lack of uniformity of the wheel-tire assembly is minimised, increasing the comfort of the driver of agricultural vehicles that are intended to travel at 50 km/h.

(50) In all the embodiments disclosed above, owing to the coupling element 21, it is possible to find at each reassembly of the rim 2 and of the disc 3 the alignment position of the respective axis, in which preset balancing of the wheel 1 is obtained.

(51) The coupling element 21, or 21a and 21b, enables centering of variable track wheels to be obtained, in which varying of the wheel track is possible owing to the presence of spacers, such as the spacers 15 in the embodiments shown.

(52) The disc 3 and the rim 2 can also be mounted according to positions that are different from one another that are illustrated in FIG. 6. With reference to FIG. 6, A-H indicate the different distances that are obtainable between the central diametral plane M of the wheel 1 and a mounting plan N of the hub 37 against which the disc 3 is mounted when the axial mounting position between the rim 2 and disc 3 is varied, for example by mounting the flange region to the left of the connecting member rather than to the right and/or by rotating the disc 3 around the vertical diameter.

(53) Varying the distance between the central diametral plane M and the mounting plane N of the hub 37 moves a pair of wheels 1 of the vehicle nearer or further that are mounted on the same axle.

(54) FIG. 6 illustrates how the position of the connecting element 21 varies with the varying of the position between the disc 3 and rim 2.

(55) The connecting element 21 ensures that the rim 2 and the disc 3 can be reassembled in the substantially concentric position even when the track of the vehicle on which the wheel 1 is mounted is varied, in accordance with one of the corresponding positions of the disc 3 and rim 2 shown in FIG. 6.

(56) Further, the embodiment in which two centering devices 8 and 9 are provided that are different from one another, ensures in an effective manner that the assembly of the rim 2 on the disc 3 occurs on the same substantially concentric position made during the wheel 1 manufacturing step, without the risk that the coupling element 21a can be coupled with the hole 10b, if diametrically opposite, or vice versa that the coupling element 21b can be coupled with the hole 10a.

(57) This significantly limits the possibility of an error in mounting the rim 2 on the disc 3, in particular in the event of replacement of the tire, in which the disc 3 remains mounted on the axis of the wheels of the vehicle and the rim 2 is remounted on the disc 3 that is already provided with the new tire. It should be observed that the wheels of agricultural vehicles such as tractors are rather bulky and positioning the rim with respect to the disc directly on the vehicle can be rather difficult when in the field.