Suspension and traction system for vehicles

Abstract

A suspension and traction system (MC) is described for vehicles equipped with a frame and a propulsive element (R), which by rolling on the ground (T) is adapted to move the vehicle relative to the ground (T). A rotary electric motor (12) operates two rotors (14, 16) independently controllable from one another to supply two epicycloidal mechanisms (20, 30) whose outer ring gears (28, 38) are independently movable to rotate about the respective solar gear (24, 34) and rigidly connected substantially to a same point (P) of the frame.

Claims

1. Suspension and traction system (MC) for vehicles equipped with a frame and a propulsive element (R), which by rolling on the ground (T) is adapted to move the vehicle relative to the ground (T), comprising: a rotary electric motor (12) comprising two rotors (14, 16) independently controllable from one another and rotatable with respect to a stator (12s) fixed on the frame, wherein the rotors (14, 16) preferably have a common rotation axis (X), two epicycloidal mechanisms (20, 30) each comprising a central solar gear (24, 34), meshing with satellite gears (26, 36), meshing in turn with an outer ring gear (28, 38); wherein in each epicycloidal mechanism one among the solar gear (24, 34) and the satellite gears (26, 36) is coupled, respectively, to a rotor (14, 16) and the other among the solar gear (24, 34) and the satellite gears (26, 36) is connected/connectable to the propulsive element (R) to impart to it equiverse angular torque to propel the vehicle on the ground (T), and the two outer ring gears (28, 38) are independently movable to rotate about the respective solar gear (24, 34) and rigidly connected substantially to a same point (P) outside the epicycloidal mechanisms, wherein on said point (P) a thrust, determined by the coordinated angular displacement of the ring gears (28, 38) about the solar gears (24, 34), can be imparted.

2. System (MC) according to claim 1, wherein the rotation axis (X) of the solar gears (24, 34) of both epicycloidal mechanisms coincides.

3. System (MC) according to claim 1, comprising an electronic control unit configured to control the two rotors (14, 16) so that they transfer torque to the propulsive element (R) through the two oidalal mechanisms, and adjust the height or distance between said point (P) and the propulsive element (R) by imposing a predetermined angular position to each ring gear (28, 38) with respect to its own solar gear (24, 34).

4. System (MC) according to claim 1, wherein said point (P) is fixed on the frame or in turn movable along a trajectory predefined by constraints with respect to the frame.

5. System (MC) according to claim 1, wherein said electric motor comprises a stator (12s) common for the two rotors (14, 16).

6. System (MC) according to claim 1, wherein the rotors (14, 16) are coaxial with each other.

7. System (MC) according to claim 1, wherein the rotors (14, 16) are arranged one inside the other.

8. System (MC) according to claim 1, wherein each rotor (14, 16) is connected respectively with the solar gear (24, 34) of an epicycloidal mechanism (20, 30), and the satellite gears (26, 36) are connected to the propulsive element (R).

9. System (MC) according to claim 1, comprising a transmission for transmitting the thrust from said point (P) towards the propulsive element (R), the transmission being structured to reverse the direction of the thrust generated on said point (P) in order to direct it towards the propulsive element (R).

10. System (MC) according to claim 1, wherein said point (P) is connected to the ring gears (28, 38) through two respective rigid arms (52, 54), wherein each rigid arm (52, 54) has a point or end connected to a ring gear (28, 38) and a point or end connected to said point (P).

Description

(1) The advantages of the invention will be clearer from the following description of a preferred embodiment of a suspension and traction system, reference making to the annexed drawing in which

(2) FIG. 1 shows a schematic three-dimensional principle view of a system:

(3) FIG. 2 shows a vertical cross-section view of the diagram of FIG. 1.

(4) The shown system MC serves to rotate a propulsive element in the form of a wheel R. The wheel, R, by rolling on a terrain T, moves an associated vehicle (not shown). The system MC is e.g. replicated on all the wheels of the vehicle.

(5) The system MC comprises a rotary electric motor 12 formed by a common stator 12s and two independent rotors 14, 16. The electrical part of the motor 12 is e.g. of a known type.

(6) The rotors 14, 16 are coaxial and have a common rotation axis indicated with X. The X axis is fixed with respect to the vehicle frame.

(7) The rotors 14, 16 are also mounted one inside the other (for example, they are two concentric sleeves), and carry torque to the motor to, respectively, a solar gear 24 and a solar gear 34, each belonging to a respective epicycloidal mechanism 20, 30.

(8) The epicycloidal mechanism 20 (30) comprises, in a known manner, a central solar gear 24 (34), which meshes with satellite gears 26 (36), which in turn mesh on an outer ring gear 28 (38).

(9) The epicycloidal mechanism 20 is independent and separate from the epicycloidal mechanism 30. In particular the ring gears 28, 38 are able to rotate with respect to the frame about the X axis independently of each other (i.e. they are not fixed to the vehicle frame).

(10) The satellite gears 26, 36 are all integrally pivoted on a support 40, which is connected to the wheel R through a shaft 90 to transfer torque to it.

(11) Each ring gear 28, 38 is connected to a respective rigid arm 52, 54, and the arms 52, 54 are connected to a common point P external to the epicycloidal mechanisms 20, 30.

(12) Point P belongs, or is connected directly, to the frame, or at the end of a lever 40 which is oscillating, approximately at its center, about an axis Y fixed with respect to the vehicle frame. The other end of lever 40 (point Q) is connected to the wheel R (for example to the shaft 90) through e.g. a rigid arm 56.

(13) The rotation of the satellite gears 26, 36 about the X axis, pushed by the rotors 14, 16, rotates the wheel R.

(14) By controlling the electric power supply of the rotors 14, 16 in the electric motor 12 (i.e. by giving more or less power than that required by the wheel R) it is possible to move the ring gears 28, 38 simultaneously about the X axis, one in clockwise direction and one counter-clockwise.

(15) E.g. the arms 52, 54 may be made to rise and push the point P upwards (in this case the point P moves away from the X axis). The lever 40 then rotates about the Y axis and moves the point Q downwards. It follows that the arm 56 pushes the wheel R downwards and towards the ground, obtaining among others a variation of the distance between the W and X axes, which are parallel in the example. In the example, the Y axis is orthogonal to an imaginary vertical plane passing through X (and/or W).

(16) One can get an upward movement of the wheel R by reversing all the motions described for the previous case (the point P approaches the X axis).

(17) Note that the rotary torque applied to the wheel R by the rotors 14, 16 and the force imparted to the wheel R towards the ground by the ring gears 28, 38 are independently controllable quantities. Then it is e.g. possible, during the acceleration phase, to push the wheel R further towards the ground to increase its gripping.

(18) The electric power supply of the motor 12 can be e.g. obtained through inverters or power-electronics stages of known topology. An electronic control unit E will take care of properly controlling the inverters or power-electronics stages so as to control the rotation speed of the wheel R and the height of the point P and Q.

(19) The electronic control unit E is easily mounted on the stator 12s, close to the windings to be powered.

(20) On the shaft 90 it is preferable to mount at least one joint, for example a. Cardan joint, for allowing or facilitating the offset of the W and X axes and/or a different orientation of the W axis.

(21) Each ring gear 28, 38 may be connected to the point P also by means other than the arms 52, 54, and the point P does not necessarily represent a geometric point, being able to be—for mechanical needs—an extended element to which the ring gears 28, 38 are connected at slightly spaced points.

(22) The lever 40 may be oscillating at a point other than its center, and the Y axis fixed with respect to the frame may be obtained e.g. by simple pivoting.

(23) The arrangement of the points Q and P on the lever 40 may vary too, as well as the means for transferring, from the point Q to the wheel R, the force generated upon displacing the ring gears 28, 38.