WO2016147067A1

WO2016147067A1 - Single-suspended-wheel steering system comprising a rotation sensor device

Info

Publication number: WO2016147067A1
Application number: PCT/IB2016/050975
Authority: WO
Inventors: Laurent Heraudet; Luca Stucchi
Original assignee: Same Deutz Fahr Group SpA
Current assignee: Same Deutz Fahr Group SpA
Priority date: 2015-03-13
Filing date: 2016-02-23
Publication date: 2016-09-22
Anticipated expiration: 2017-09-13
Also published as: CN107531091A; EP3268263B1; JP6640240B2; CN107531091B; EP3268263A1; JP2018509336A

Abstract

A single-suspended-wheel steering system (5) of a vehicle for agricultural use. The system (5) having a wheel carrier (51) and an arm (52) engaged to each other via a joint group (1). The joint group (1) comprises: i) a pin (10) that extends along a pivot axis (P-P) between a first end (11) and a second spherical end (12); ii) 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); iii) a rotation 1 sensor device (30) comprising a detection element (31) suitable to detect the angle of rotation of the central body (21) around said axis of rotation (R-R).

Description

DESCRIPTION

"SINGLE-SUSPENDED-WHEEL STEERING SYSTEM COMPRISING A

ROTATION SENSOR DEVICE"

Field of application

[0001] This invention relates to a single-suspended- wheel steering system of a vehicle for agricultural use and a tractor or riding mower comprising said single- suspended-wheel system.

[0002] In other words, in this description, "single- suspended-wheel steering system" identifies a system with independent wheel suspensions.

[0003] Furthermore, in the following description, the phrase "vehicles for agricultural use" refers to those vehicles typically suitable to move and operate on agricultural land; the term "tractor" means both agricultural tractors and, more in general, large machines, such as earth moving machines derived from agricultural tractors and, in general, specific machines power operations, such as actions directly on the ground, such as ploughing or the loading/unloading of agricultural material; the term "riding mower" refers to that type of vehicle, typically compact in size, for example used in the viticulture, and therefore typically suitable to move in the space between two adjacent rows. State of the art [0004] The single—suspended—wheel steering systems currently known provide the vehicle a plurality of advantages such as large steering angles, an effective shock absorption of the vehicle, the independence of the wheels on the ground in such a way to deal with situations in which only three wheels are on the ground while one is raised from it, i.e., the situation that typically occurs with solutions with rigid axle.

[0005] However, the known single-wheel-suspended steering systems have the main problem of difficulty of detecting the steering angle. However, this detection is necessary to allow some basic functions of the vehicle for agricultural use such as, for example, the disengagement of the drive wheels, or the management of automated movement of the vehicle by means of movement systems with GPS.

[0006] In some typical prior art solutions, this issue has been resolved by maintaining the mechanical components unchanged and interfacing them with a specific, particularly complex sensor system. However, these particularly complex sensor solutions are unreliable and subject to breakage, particularly in the light of the fact that find application in demanding environments such as agriculture.

[0007] In further typical prior art solutions, this issue has instead been resolved by proposing particularly complex mechanical components interacting with a simpler sensor system; however, these solutions have undesirable overall dimensions and require complex manufacturing steps .

Presentation of the invention

[0008] The objective of this invention is to provide a single-suspended-wheel steering system that overcomes the above-mentioned problem typical of the prior art by providing a single-suspended-wheel steering system in which the detection of the steering angle of the wheel is effective and reliable.

[0009] This objective is achieved by a single- suspended-wheel steering system realised according to claim 1, and by a tractor or riding mower in accordance with claim 15. The dependent claims describe further variants of preferred embodiments.

Description of the drawings

[00010] The characteristics and advantages of a single- suspended-wheel steering system according to this invention will be apparent from the following description, given by way of non-limiting example, in accordance with the accompanying figures, in which:

Figure 1 shows a perspective view of a single- suspended-wheel steering system covered by this invention according to a preferred embodiment;

Figure 2 illustrates an exploded perspective view of a portion, in particular a joint group, of the single- suspended-wheel steering system of Figure 1;

- Figure 3 shows a side view of the portion of the single-suspended-wheel steering system of Figure 2 according to a preferred embodiment;

Figure 3a shows a sectional view of the portion of the single-suspended-wheel steering system of Figure 3 along a sectional plane V-V;

Figure 4 shows a perspective view of a single- suspended-wheel steering system covered by this invention according to a further preferred embodiment;

Figure 5 illustrates an exploded perspective view of a portion, in particular a joint group, of the single- suspended-wheel steering system of Figure 4;

Figure 6 shows a side view of the portion of the single-suspended-wheel steering system of Figure 5;

Figure 6a shows a sectional view of the portion of the single-suspended-wheel steering system of Figure 6 along a sectional plane VI-VI;

Figure 7 shows a perspective view of a single- suspended-wheel steering system covered by this invention according to a still further preferred embodiment;

- Figure 8 illustrates an exploded perspective view of a portion, in particular a joint group, of the single- suspended-wheel steering system of Figure 7 ;

Figure 9 shows a side view of the portion of the single-suspended-wheel steering system of Figure 8 ;

- Figure 9a shows a sectional view of the portion of the single-suspended-wheel steering system of Figure 9 along a sectional plane VI I-VI I;

Figure 9b shows a top view of the portion of the single-suspended-wheel steering system of Figure 9.

Detailed description

[00011] In accordance with the accompanying figures, reference number 5 indicates, in its entirety, a single- suspended-wheel steering system of a vehicle for agricultural use (not shown) connected to a wheel assembly (not shown) . Preferably, the vehicle is a tractor. Preferably, the vehicle is a riding mower.

[00012] The accompanying figures do not even show the wheel assembly; in fact, the single-suspended-wheel steering system 5 is independent of the type of wheel assembly, tyre or tyres, for example twinned, supported.

[00013] Preferably, the single-suspended-wheel steering system 5 is the front of the vehicle for agricultural use. In other words, the wheel assembly that the single- suspended-wheel steering system supports is a front wheel carrier assembly. [00014] In a preferred embodiment, the single- suspended-wheel steering system 5 is a drive wheel; in other words, it is connected to the transmission means of the vehicle to transmit the motion to the ground through the respective wheel assembly. In the embodiment in which the single-suspended-wheel steering system is in the front, it thus refers to vehicles such as to present, directly or optionally, traction of four drive wheels.

[00015] According to a preferred embodiment, the system 5 comprises a wheel carrier 51 for the wheel assembly and at least one arm 52 for the support and shock absorption of the wheel carrier 51, preferably the system 5 is a mechanical suspension system with quadrilateral structure having an upper arm 52' and a lower arm 52". The respective wheel carrier 51 is thus supported superiorly by the upper arm 52' and inferiorly by the lower arm 52".

[00016] According to a preferred embodiment, the system 5 also comprises a joint group 1 suitable to allow the engagement between wheel carrier 51 and respective arm 52. Preferably, the joint group 1 allows rotation of the wheel carrier 51 relative to the arm 52 about an axis of rotation R-R.

[00017] 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. [00018] According to a preferred embodiment, the first end 11 is suitable to be fixed to the wheel carrier 51 in such a way that a rotation of the wheel carrier 51 corresponds to a rotation of the pin 10.

[00019] According to a further embodiment, the first end 11 is suitable to be fixed to the arm 52, so as to maintain its fixed angular position with respect to the pivot axis P-P pin and with respect to the axis of rotation R-R, while the wheel carrier 51 is suitable to rotate around it.

[00020] In other words, the first end 11 is suitable to be connected to the wheel carrier 51 or to the arm 52 by appropriate means such as a screw-bolt system, or by means of threading directly formed on it.

[00021] According to a preferred embodiment, the second spherical end 12 is instead housed in the arm 52 or is instead housed in the wheel carrier 51.

[00022] In a further preferred embodiment, the joint group 1 respectively comprises a wheel carrier flange 510 and/or an arm flange 520 suitable to be respectively engaged by the first or second end of the pin 10 and in turn fixed to the wheel carrier 51 and to the arm 52 for example by means of appropriate locking means, for example by means of screws.

[00023] Preferably, 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.

[00024] In other words, as a function of the different embodiments, the wheel carrier 51 or the arm 52 and/or respectively the wheel carrier flange 510 or the arm flange 520 have, along the axis of rotation R-R, an axially symmetric housing cavity 500; said housing cavity substantially contains the joint group 1 in its entirety; in fact, only a portion of the pin 10 extends to the outside of said housing cavity 500, in particular the first end 11.

[00025] Preferably, the central body 21 comprises a ball housing 210 delimited by the housing walls 210' , in which the second spherical end 12 is received.

[00026] According to a preferred embodiment, the second spherical end 12 is connected to the central body 21 by means of a transverse pin 121 that 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 free rotation of the second spherical end 12 around the centre C in all degrees of freedom.

[00027] According to a preferred embodiment, the central body 21, on the housing walls 210' , has two pin slots 215 radially opposite with respect to the axis of rotation R-R, which extend parallel to it, in which the ends of the transverse pin 121 are housed free to move.

[00028] In other words, the two pin slots 215 allow movements of the pin 121 such as to recover, for example, shaking of the wheel carrier or mounting tolerances of the wheel carrier to the arm. Note that the angular movement of the pin 121 in the slots 215 is shown by the dashed lines in Figures 3a, 6a, and 9a.

[00029] 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 an abutment element 212 inside it on which the second spherical end 12 acts, free to move; in fact, the abutment element 212 has a concave shape such as to allow the housing and 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, i.e., the distance from the centre C to the outer wall of the second spherical end 12. [00030] According to a preferred embodiment, the abutment element 212 is made of an anti-friction material, i.e., with a low coefficient of friction, preferably, made of a material selected from the group of polymers or metals with a low coefficient of friction or low-friction, for example the bronze alloys.

[00031] 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.

[00032] In a preferred embodiment, the rotation means 25 comprise two conical roller bearings 251 arranged in such a way that the disposition angles of the cones are opposite and facing the centre of the joint group 1 where the second spherical end 12 is preferably placed. However, embodiments are known in which the rotation means 25 comprise one or more ball or sliding bearings.

[00033] In other words, the rotation means 25 are suitable to manage both the axial loads and the radial loads .

[00034] According to a preferred embodiment, the central body 21 is constituted by two main portions.

[00035] 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 suitable to engage each other, for example by screwing one to the other. Preferably, the first portion 21a and second portion 21b are flanged radially in such a way as to enclose the rotation means 25 in a sandwich between the respective flanges.

[00036] According to a preferred embodiment, the joint group also comprises a rotation sensor device 30 suitable to detect the angle of rotation of the central body 21 around said axis of rotation R-R; in other words, the rotation sensor device 30 is suitable to detect the rotation angle of the wheel carrier 51, i.e., the steering angle of the vehicle.

[00037] As a function of the different embodiments, the rotation sensor device 30 is respectively fixed to the arm 52 or the wheel carrier 51 and/or to the wheel carrier flange 510 or to the arm flange 520.

[00038] Preferably, the rotation sensor device 30 comprises a detection element 31 positioned on the axis of rotation R-R. In other words, the detection element 31 is located in the single-suspended-wheel steering system 5 along the rotation axis R-R system. [00039] In a preferred embodiment, the rotation sensor device 30 comprises a flange 32 for fixing the rotation sensor device 30 to the arm 52; the fixing is executable with appropriate means for example using specific locking screws screwed through the flange 32 on the arm 52. In further embodiments, the flange 32 is, instead, suitable to carry out the fixing of the rotation sensor device to the wheel carrier 51 or to the wheel carrier flange 510.

[00040] 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.

[00041] In a preferred embodiment, the detection element 31 interfaces with the second portion 21b.

[00042] 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.

[00043] According to a preferred embodiment, the detection element 31 is suitable for detecting angles of rotation around the axis of rotation R-R, starting from a zero position, up to ±90°, preferably up to ±60°.

[00044] In other words, the detection element 31 integrally housed in the respective seat 321, for example fixed by means of appropriate fixing means such as fixing screws screwed to the flange 32, is suitable, through the detection aperture 320, to detect the rotations of the flange 320 with respect to the central body 21.

[00045] In a preferred embodiment, the flange 32 and the rotation means 25 are suitable to support the central body 21, the pin 10, to the arm 52 or to the wheel carrier 51 or to the wheel carrier flange 510.

[00046] Therefore, as a function of the type of configuration, the detection element 31 is suitable to detect a rotation of the central body 21, for example induced by the pin 10 through the ping 121, with respect to the flange 320. Conversely, in other embodiments, the central body 21 is maintained in a fixed position by the pin 10, through the pin 121, and it is the flange 320 that is rotated: so, the detection element 31 is suitable to detect the relative rotation of the central body 21 with respect to the flange 320, i.e., the rotation of the flange 320 with respect to the central body 21.

[00047] 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 linked to mounting tolerances. In other words, the detection element 31 is suitable to detect the related movement of said sleeve 300. [00048] Preferably, the realignment sleeve 300 is fixed to the central body 21.

[00049] In a preferred embodiment, the realignment sleeve 300 is made of an elastically yielding material, for example a polymeric rubber material.

[00050] Innovatively, the single-suspended-wheel steering system of this invention allows achieving the intended purpose of the invention, i.e., to provide a precise detection of the angle of rotation of the wheel carrier.

[00051] Advantageously, the single-suspended-wheel steering system is suitable to detect the steering angle without the need of important design and manufacturing distortions of the system itself, unlike what is the case in the state of the art solutions.

[00052] Moreover, advantageously, the detection is always reliable and correct in real time, since it is taken from the central body, without, instead, being conditioned by the relative movements of the ball joint; the use of the steering angle and the management of this information by specific systems such as that of the management of the four-wheel drive or that of movement with an automated system with GPS, is not vitiated by errors or by related movements.

[00053] A further advantage is that of having a single- suspended-wheel steering system in which the movement axes of the joint are isolated from each other and therefore the rotations are- them are effectively measurable .

[00054] A still further advantage resides in the fact that the single-suspended-wheel steering system is rigid and strong, and therefore suitable to be used in hostile environments such as agriculture.

[00055] Moreover, advantageously, the joint group is not bulky and, instead, is suitable to be integrated in the solutions already known for example of suspension arms .

[00056] Advantageously, the single-suspended-wheel steering system can be integrated in solutions of vehicles such as tractors, i.e., of large dimensions and subject to important actions and reactions, for example with the ground.

[00057] In addition, advantageously, the single- suspended-wheel steering system can be integrated into solutions such as tractors in which the preservation of the overall dimensions is the main issue here effectively resolved .

[00058] In the embodiment in which the system comprises a joint group having specific flanges, a further advantage resides in the fact that the design and production of the components of the wheel carrier assembly and arm in that they must be provided with specific slots for the fixing of the respective flanges, while their design is not linked to the shape of the joint group and its housing in the respective components.

[00059] It is clear that one skilled in the art, in order to meet specific needs, may make changes to the single-suspended-wheel steering system, the tractor and the riding mower described above, all contained within the scope of protection defined by the following claims.

Claims

1. A single-suspended-wheel steering system (5) of a vehicle for agricultural use connected to a wheel group, wherein the system (5) comprises:

- a wheel carrier (51) for the wheel group;

- at least one arm (52) for the support and damping of the wheel carrier (51); and

- a joint group (1) suitable to allow the engagement between wheel carrier (51) and arm (52) for the rotation of the wheel carrier (51) relative to the arm (52) about an axis of rotation (R-R) ;

wherein said joint group (1) comprises:

i) a pin (10) that extends along a pivot axis (P-P) between a first end (11) and a second spherical end (12); ii) 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);

iii) a rotation sensor device (30) comprising a detection element (31) positioned on the axis of rotation (R-R) and suitable to detect the rotation of the central body (21) around said axis of rotation (R-R) with respect to it; wherein the joint group (1) is substantially housed in the wheel carrier (51) or arm (52) , and the first end is integrally connected respectively to the arm (52) or to the wheel carrier (51).

2. System (5) according to claim 1, wherein the central body (21) comprises a ball housing (210) delimited by housing walls (210' ) , wherein 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) to engage said housing walls (210'), in such a way that the pin (10) is free to rotate about said transverse axis (Y-Y) .

3. System (5) according to claim 2, wherein the central body (21) has, radially opposite with respect to the axis of rotation (R-R) , on the housing walls (210' ) , two pin slots (215) that extend parallel the axis of rotation (R- R) , in which the ends of the transverse pin (121) are housed, free to move.

4. System (5) according to any of claims 2 or 3, wherein the central body (21) comprises an abutment element (212) suitable to keep the centre (C) fixed along the axis of rotation (R-R) .

5. System (5) according to any of the preceding claims, wherein 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 is housed.

6. System (5) according to any of the preceding claims, wherein the central body (21) comprises a first portion

(21a) and a second upper 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) .

7. System (5) according to any of the preceding claims, wherein the rotation sensor device (30) comprises a flange (32) for fixing the rotation sensor device (30), in which the flange (32) has, along the axis of rotation (R-R), a detector aperture (320) through which is inserted the detection element (31) to interface with the central body (21), preferably with a second portion (21b) .

8. System (5) according to claim 7, wherein 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) .

9. System (5) according with any of claims 7 or 8, wherein the detection element (31) is suitable for detecting angles of rotation around the axis of rotation (R-R), starting from a zero position, up to ±90°, preferably up to ±60°.

10. System (5) according to any of claims 7 to 9, in combination with any of claims 1 to 6, wherein the flange (32) and rotation means (25) are suitable to support the central body (21), the pin (10) and the wheel carrier (51), on the respective component in which the rotation device (20) is housed.

11. System (5) according to any of the preceding claims, wherein the joint group (1) comprises an arm flange (520) suitable to be integrally connected with the arm (52) and suitable to be rotationally engaged with the first end (11) of the pin (10) .

12. System (5) according to any of the preceding claims, wherein the joint group (1) comprises a wheel-carrier flange (510) suitable to be integrally connected with the wheel carrier (51) and suitable to house and be rotationally engaged with the rotation device (20) and with the rotation sensor device (30) .

13. System (5) according to any of claims 10 to 12, wherein the wheel carrier group (51) or the arm (52) and/or the wheel carrier flange (510) or the arm flange (520) have, along the axis of rotation (R-R) , an axially symmetric housing cavity (500), substantially for housing the joint group (1) .

14. System (5) according to any of the preceding claims, wherein the wheel group, connected by a single-suspended- wheel steering system (5), is at the front.

15. Tractor or riding mower comprising a single- suspended-wheel steering system (5) according with any of the preceding claims, wherein the system is a drive system.

16. Tractor or riding mower according to claim 15, wherein the single-suspended-wheel steering system is placed on the front axle.