Not applicable.
Not applicable.
Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates to a gear-motor with integrated brake and inverter for direct transmission to the wheel of an electrical traction vehicle according to the characteristics of the pre-characterizing part of claim 1.
The electric-traction vehicle with said gear-motor with integrated brake and inverter is also part of the present invention, according to the characteristics of the pre-characterizing part of claim 22.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
In the field of motion transmission to the driving wheels of vehicles, particularly industrial vehicles, e.g. tractors, forklift trucks, or operating machines, electric or hydraulic motors are normally used.
Motors are commonly associated to a mechanical gear-reducing device that transmits motion to the wheels.
Compact configurations of these gear-reducing devices exist, called axles, which dispense the torque supplied by a single motor to the two wheels by means of a distribution differential group. Other axle configurations provide the use of two motors, one for each wheel.
A second configuration of the traction system provides the use of two completely independent transmissions, one for each driving-wheel, with the aid of a transmission system with incorporated gear-reducing device and brake.
The steering is controlled by an electronic system monitoring signals from the speed sensors on each of the two motors and by a transducer measuring the steering angle.
The current trend aims at using faster and faster, as well as more and more compact, electric motors, in order to reduce the external encumbrance of the gear-motor system and end users require more and more silent machines.
Closest Prior Art to the Invention
Among the prior art techniques, the closest solution to the present invention is the one described in patent WO2007022865, of the same applicant. WO2007022865, describing a gear-motor with integrated brake for direct drive to the wheel of an electric-traction vehicle in which the traction motor is integrated with a reduction transmission connected to the driving-wheel, and in which the traction motor includes a passing driving axle including a pinion on the wheel side which internally gears to the reducer-transmission system integrated with the wheel for the traction motion in a corresponding gear chamber and on the side opposite to the wheel is keyed to a braking system, which is also integrated, and cased with the same assembly, in a corresponding opposite braking chamber forming a detachable motor-brake assembly and in which the transmission reducing group is housed in a structural supporting casing connectable to the vehicle and the motor group has its supporting casing fixed as a cover to the structural supporting casing covering the reducing system and allowing free access after its opening.
Issues of the Prior Art
The prior art techniques providing the use of the axle configuration highly limit designers of industrial vehicles, as the axle size and its encumbrance do not allow a full operational freedom, since the vehicle track, the vehicle frame shape and, in case of forklift trucks, the anchorage system choice of the stanchion, remain fixed.
The traction system configurations providing the use of two completely independent transmissions, one for each driving-wheel, with the aid of a transmission system with integrated gear-reducing device and brake do not limit the designer, showing however issues in terms of high costs in their embodiments and having numerous additional components that need to be duplicated and arranged on the vehicle, this determining an increase of required space for the installation of transmission control components.
Drawbacks of the present state of the art also include:
The configuration providing two separate transmissions requires the arrangement of a double wiring carrying the power supply and thermal and speed sensor cables to the electronic control junction box.
Even the solution described in WO2007022865 shows drawbacks due to the overall encumbrance of the gear-motor device and to the size of its corresponding components to take into account transmitted power and torque. Additionally, it is necessary to provide the positioning of control devices on the electric-traction vehicle and arrange the corresponding wiring between the control devices and the gear-motor group, with the consequent need to carefully analyse the installation to take into account even the running of all wirings, including power wirings and motor control wirings.
The aim of this invention is that of implementing a compact and highly reliable integrated gear-motor device with braking function and electronic control, being cost-effective in terms of implementation, installation and maintenance.
The aim is achieved by means of the characteristics of the main claim. Sub-claims represent advantageous solutions.
The solution in accordance with the present invention, by means of the significant creative contribution the effect of which constitutes an immediate and non-negligible technical progress, shows many advantages.
The system in accordance with the present invention allows providing a motor being highly compact and, as a result, cost-effective and easy to install.
Moreover, the maximum transmission input torque is shown to be almost halved, allowing the use of smaller gears; particularly, the input pinion can be easily produced directly on the motor shaft.
Moreover, the reduction ratio of the gear-reducing device increases proportionally to the speed.
Finally, by arranging an emergency dynamic brake or a parking-brake between motor and gear-reducing device, this will have to develop a little braking torque, with consequent advantages in terms of component sizing, weight, total cost, operational cost-effectiveness and energy saving.
Furthermore, the invention solution considerably reduces the length of power cables that run from the motor control inverter to the motor itself, with significant advantages in terms of installation and maintenance simplicity, as well as in terms of overall costs.
The following describes a performable solution with reference to the attached drawings, which shall be considered as a non-limitative example of the present invention in which:
With reference to the figures, the gear-motor with integrated brake and inverter for direct transmission to the wheel according to the present invention allows obtaining a single body consisting (
Advantageously, all misalignment and coupling issues possibly arising during the installation of an external motor can be therefore avoided. The casing (34) includes one or more chambers (41,42) which may be used as an oil reserve for the braking chamber and/or as a recirculation channel of the oil itself, in case all the reducer oil is to be used for cooling purposes.
In the solution according to the present invention the motor (24) shaft also directly constitutes the first pinion (29) of the first stage of reduction of the gear-motor. In fact (
Consequently the shaft of the motor (24) performs the triple function of:
This solution produced a very cost-effective and compact transmission able to reach almost absolute constructive precision limits: by obtaining the input gear of the gear-reducing device, namely the first pinion (29), directly on the shaft of the motor (24) the reduction gears can be increased with consequent possibility to increase the rotational speed of the motor thanks to a highly precise construction.
Furthermore, unlike the prior art techniques, the present invention provides the use of a high-speed motor (24), which is made possible by the fact that, thanks to the integration of the motor (24) itself with the gear-reducing device, a single body is formed with a particularly precise coupling. The use of a high-speed motor, for example a motor with maximum speed of about 8000 to 12000 RPM, allows important advantages compared to the prior art techniques:
The gear-motor can provide or not provide the use of oil-immersed motors, thus performing a system in which the oil of the gear-reducing device recirculates through appropriate channels passing through the motor (24) and the brake (49), however without passing close to the motor rotor to perform an overall cooling form of the gear-motor in general: it is therefore possible to avoid the use of sealing gaskets among motor (24), gear-reducing device (50) and brake (49), to the benefit of its mechanical efficiency.
The motor wheel (27) is actuated by the respective hub (1) which is integrated or however integral (
The spider (11) in turn receives the motion by means of satellites (12) of the second stage of reduction that, in the shown embodiment (
All the gears of the gear-reducing device (50) are incorporated in the first chamber (41) or chamber of the gear-reducing device. By means of a connecting channel (45), the first chamber (41) is in flow communication (
The motor (24), in correspondence of the side opposite to the one on which the interface between motor (24) and gear-reducing device (50) is located, is closed (
As explained above, the casing (34), consisting of cover (16) and box (7), constitutes the container containing both the motor (24) and the gear-reducing device (50) also allowing full access to the gear-motor in that, by dismantling the casing (34) in its two constituent parts, the gear-motor opens very easily in two parts showing the gear-reducing device (50) on one side and the motor (24) on the other side. Consequently, access to the gear-motor is particularly simple and complete in correspondence with all its components with key advantages in terms of supervision and maintenance simplicity.
With respect to the prior art techniques, the external brake lever (26) for the mechanical operation of the brake does not act centrally on the axis of the gear-motor (51) in correspondence of the head (35) of the motor (24), but the external brake lever (26) for the mechanical operation of the brake (49) acts (
The characteristics and inventive technical solutions related to the use of a high-speed motor (24), to the arrangement of the braking system (49) in an intermediate position between the motor (24) and the reducer (50), to the use of a single closure casing (34) of the motor (24) and reducer (50) assembly, in addition to the above-mentioned advantages in terms of compactness and lightness of the gear-motor (51) in general together, also allows the housing (
All this involves important benefits and obtains a gear-motor (51) assembly with compact, solid, cost-effective, and light integrated inverter (32), with benefits also in terms of overall consumption of the controlled electric-traction vehicle.
The braking system (49) consists of the friction disc (20) or second disc, the action of which is controlled (
The hydraulic activation occurs (
Alternatively, the piston (25) can be brought in pushing condition even by acting on an external brake lever (26) which exerts its own action directly on the piston (25) for the control of the braking action, thus performing a mechanical drive.
Advantageously, the use of a high-speed motor, indicatively 8000 to 12000 RPM, allows the reduction, down to almost a half, of the input maximum torque to the transmission, allowing the use of smaller gears. Consequently higher reduction ratios can be used. Approximately, while the prior art required the use of gear-reducing devices with a reduction ratio of about 20/30, the inventive system allows the use of a reduction ratio of about 50/60.
Advantageously the availability of a particularly compact gear-motor assembly (51) with integrated inverter (32) also allows having configurations of electric-traction vehicles with a complete group for each traction wheel allowing the obtainment of single controls on each of the driving wheels, each equipped with its own gear-motor (51) with integrated inverter (32). Alternatively, the inventive solution can be also applied in correspondence with a single traction wheel, for example, but without limitation within the aim of the present invention, in case of three-wheel electric-traction vehicles.
Without limitation within the aim of the present invention, examples of electric-traction vehicles on which the gear-motor (51) with integrated inverter (32) according to the present invention can be applied are work vehicles, tractors, forklift trucks.
The hub (1) of the wheel (27) is supported (
The existing spans (47) (
Basically, the present invention relates to a gear-motor (51) with integrated brake (49) for direct transmission to the motor wheel (27) of an electric-traction vehicle in which the traction motor (24) is integrated into a gear-reducing device (50) connectable to the driving wheel (27) of the electrical traction vehicle in correspondence of a hub (1), in which the gear-reducing device (50) is housed into a structural supporting box (7) connectable to the electric-traction vehicle by means of fixing holes (52). The traction motor (24) has a support casing that can be fixed as a cover (16) to the box (7), the box (7) and the cover (16) constituting a single structural support casing (34) of the gear-motor (51), the cover (16) covering and closing the gear-reducing device (50) within the box (7), the opening of the cover (16) allowing free access to the gear-reducing device (50) on one side and to the motor (51) on the opposite side. The traction motor (24) is a compact high speed motor (24) with maximum speed of about 8000 to 12000 RPM, whose transmission shaft is coupled in correspondence of the first pinion of the gear-reducing device (50) or is integral with the first pinion of the gear-reducing device (50). Preferably the driving and control inverter (32) of the motor (24) is housed in correspondence with the closing head (35) of the motor (24), the driving and control wiring between the inverter (32) and the motor (24) having a minimum length given by the small distance between the motor (24) and the inverter (32) housed in correspondence of the closing head (35) of the motor (24), the driving and control wiring of the gear-motor (51) by means of controls coming from the electrical traction vehicle comprising power supply cables of the inverter (32) connected to feeding connectors (31) and a control cable connected to a data line connector (33) of the inverter (32).
The gear-reducing device (50) is preferably a two-stage gear-reducing device of which a first stage is coupled to the shaft of the motor (24) and a second stage is an epicycloidal stage coupled to the hub (1).
Finally, the present invention also relates to an electrical traction vehicle including at least one gear-motor (51) according to the present invention for direct transmission to the motor wheel (27) of the electric-traction vehicle.
The description of the present invention, in its preferred embodiment, makes reference to the enclosed figures, it is however obvious that many possible modifications, changes and variants will be immediately clear to those skilled in the art in light of the previous description. Therefore, it should be noted that the previous description is not limitative of the invention, but includes all modifications, changes and variants in accordance with the appended claims.
The following nomenclature has been used with reference to the reference numbers indicated in the enclosed figures:
1. Wheel hub
2. First bearing or bearing of the wheel hub
3. Spacer
4. Adjusting shim
5. Track for the gasket
6. Gasket
7. Box
8. Locking ring of the rim
9. First disc or rim-carrier disc
10. First rim or rim of the epicycloidal stage
11. Spider
12. Satellite
13. Locking ring
14. Transmission
15. Second bearing or transmission bearing
16. Supporting casing or cover
17. Third bearing or bearing of the first stage pinion
18. First flange or dragging flange
19. Counter disc
20. Second disc or friction disc
21. Third disc or pressure disc
22. Second flange or pressure disc supporting flange
23. Internal brake lever
24. Motor
25. Piston
26. External brake lever
27. Wheel
28. Second rim or rim of the first reduction stage
29. First pinion or pinion of the first reduction stage
30. Second pinion or pinion of the epicycloidal stage
31. Inverter feeding connector
32. Inverter
33. Inverter data line connector
34. Casing
35. Head or motor closing head
36. First end
37. Second end
38. Force application point
39. Fulcrum
40. Elastic means
41. First chamber or chamber of the gear-reducing device
42. Second chamber or additional container integrated in the fusion
43. Third chamber or chamber of the disc brake
44. Injection chamber
45. Connecting channel
46. Connection
47. Span
48. Sliding and support means
49. Brake or braking system
50. Gear-reducing device
51. Gear-motor
52. Fixing holes
Number | Date | Country | Kind |
---|---|---|---|
UD2012A000001 | Jan 2012 | IT | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP2012/005390 | 12/28/2012 | WO | 00 | 7/2/2014 |