WO2007017221A1

WO2007017221A1 - Electromotive transmission for vehicles with multifunction integrated braking device

Info

Publication number: WO2007017221A1
Application number: PCT/EP2006/007788
Authority: WO
Inventors: Luigino Pozzo
Original assignee: Pro-Mec S.R.L.
Priority date: 2005-08-10
Filing date: 2006-08-07
Publication date: 2007-02-15
Also published as: ITUD20050133A1

Abstract

Electromotive transmission with multifunction integrated braking device for vehicles, of the type in which the transmission substantially consists in a ratio-motor group with integrated brake, comprising: traction motor (3) and integrated transmission with brake (1) , in an oil bath. It substantially includes two chambers (G, 7) , a first chamber (6) for the gear reducing device transmission system (GR) and , a second chamber (7) where the respective braking system (D) is found, said chambers being equipped with lockable intercommunication passage/s (8, 9) for the possible passage of the oil from one chamber to the other. An external cooling oil container (4-5) is also provided.

Description

DESCRIPTION

ELECTROMOTIVE TRANSMISSION FOR VEHICLES WITH MULTIFUNCTION INTEGRATED BRAKING DEVICE

Technical Field The present invention relates to an electromotive transmission for vehicles with a multifunction integrated braking device, whose characteristics correspond to the precharacterizing part of the main claim. The vehicles equipped with said transmission also form the object of the present invention. The field of application is directed to the vehicle sector in which a braking system directly integrated onto the respective motor is required, e.g. for electric vehicles, forklift trucks, electric-traction or hydraulic tractors etc.. In substance the invention is particularly directed to industrial vehicles, e.g. tractors, forklift trucks, operating machines. However, said list is not to be considered as limitative.

The preferred application is found in all transmission apparatus equipped with an oil bath integrated braking system preferably having a ring-disk brake pack. Background Art In the present state of the art the respective electric or hydraulic engines are known in said vehicles: a) that independently operate each driving-wheel, in which each motor is connected to the axis of the wheel by a transmission system with a gear- reducing device having an incorporated brake; b) that connect to the axis of the wheel by a transmission system with a gear-reducing device and incorporated brake, followed or preceded by a differential group that transmits the motion of the motor to both wheels. In both cases, the use of separated brakes generally integrated into the wheels is saved, instead they are integrated into the reducer system of the transmission. In this case there is the advantage of a considerable cost reduction and simplification of the entire traction system and braking/traction and braking system. Drawbacks of the Present State of the Art

The following are drawbacks of the aforementioned present state of the art:

1 ) Difficulty in accessing the braking system as it is generally incorporated between the transmission reducer system, therefore it is necessary to dismantle the entire reducer transmission system in order to access the braking device.

2) The use of brake discs deteriorates the oil of the gear-reducing device compromising the life of bearings and of gears.

3) Furthermore, an oil-immersed braking system as mentioned as above has the drawback that is has to use a type of oil that finds a compromise between the two uses wherein the gear-reducing device requires an extremely viscous and adhesive oil while the braking system requires an extremely fluid oil.

4) The oil-immersed braking system requires an optimal oil level that is generally different to the optimal level required for the correct working of the gear-reducing device.

A part of the aforementioned drawbacks find a solution by making the braking system independent from the transmission system (e.g. Italian Patent Applications n.UD97A000217 of 25/11/97 and n.98121712.8 of 13/11/98).

The use of the system to separate the chambers of the gear-reducing device and the brake, claimed in the aforementioned Patent Applications, on one hand solves certain drawbacks, but on the other hand can generate a new disadvantage, namely:

5) Given the increasingly exiguous space available, the amount of oil that can be introduced into the chamber of the brake device is sufficient to dissipate the heat produced m during braking only if the brake is not used in a heavy way; otherwise a considerable increase of localised temperature in the brake area is noted, while the rest of the transmission is generally colder. The excessive heating is likely to degrade the properties of the oil itself. Scope of the Invention The scope of the invention is to solve the aforementioned problems and drawbacks and furthermore, without greater costs and without reducing reliability:

- improve functionality and yield;

- increase performance; - increase reliability;

- make the system more accessible and compact.

Solution of the Problem and Identification of the Characteristics of the Invention.

The problem is solved with the characteristics of the main claim. The sub-claims represent preferred advantageous solutions that provide an improved performance. Advantages In this way there is the advantage of:

- improving functionality and yield; - increasing performance;

- increasing reliability;

- making the system more accessible and compact,

- making exchange and maintenance easier. Description of the Preferred Solution

For a better understanding the invention is described in a preferred solution with the aid of the attached Figures, wherein:

- Fig.1.- represents the perspective view of the assembly of the ratio- motor-brake group at the side of the respective oil cooling radiator.

- Fig.2.- represents the sectional view of the reducer-brake part of the group in Fig.1 , in which the main components and the pass ducts of the oil from one chamber to the other are shown.

- Fig.3.- represents the sectional view as in Fig.2, but in which the oil levels in the two chambers are shown, when it is applied to the circulation system.

Detailed Description of the Invention in relation to the Figures According to the Figures it is observed that the invention refers to a ratio- motor-brake group for vehicles as substantially visible in Fig.1. Figure 2 instead shows a section of the system, in which the creation of a communication duct between the two chambers has been carried out; the form of the gears is opportunely shaped for pumping oil inside the brake chamber. Figure 3 shows the oil levels that are obtained in the two communicating chambers when the recirculation-pumping system integrated into the reducer chamber is applied.

From the above it is understood that with this invention a flexible system has been created that solve all the the problems described above. In particular communication openings (8;9) have been produced on the separating wall between the gear-reducing device and the brake device: these openings (8;9) can be opportunely obstructed with closures to restore the condition of physical separation of the two chambers (6-A, 7- B), the numbers (6,7) indicating the chambers and (A₁B) indicating the respective oil quantities contained therein and indicated as different levels: (Level 1 ) and (Level 2).

The cap of the braking system, directed towards the exterior has been equipped moreover with two hydraulic plugs allowing the connection of the brake chamber to an external recirculation circuit by means of two respective pipings (5).

Maintaining the advantages of the separation of chambers it is possible to use the new system in 3 different solutions.

1 ) Double chamber with internal oil recirculation, where through communication openings between the two chambers an internal recirculation is created wherein, using the particular geometric shape, the internal mechanical elements can generate a pumping effect of the oil that is pushed to fill the brake chamber. In this way a recirculation effect is achieved in which all the oil of the transmission participates in the dissipation of the heat generated by the brake. Moreover, it can be generated when required in the two chambers of different optimal levels (Level 1 , Level 2), for each chamber, for example with the pumping effect. However, it will have a decantation effect in the brake chamber (7-B), therefore the heaviest impurities are not introduced into the recirculation flow and therefore do not pass to the gear-reducing device chamber (6-A), where they could damage the respective gears.

This solution can be introduced for heavy applications of the brake, with the disadvantage of the use of only one type of oil because the two chambers (6.7) are placed in communication by the open ducts (8.9) and there is no longer any physical separation between the oil of the brake (b) and that of the gear-reducing device (A).

2) In the event of heavy braking it is possible to use an additional solution with separate chambers, but joining the two brake chambers by means of the aforementioned hydraulic plugs with respective external connecting pipes (5), to an external container (4) that acts as an oil reserve and heat dissipator. In this case different oils can be used for the gear-reducing device and brake device and the dissipator function of the container/tank allows the operational temperatures to be maintained at an optimal value.

3) In 'normal' use conditions of the brakes the two separate chamber structure(6.7) can moreover be used, renouncing both the internal recirculation, obstructing the communication channels (8.9), and the external exchanger/container (4.5); clearly different oils can be used when the physical separation of the chambers is maintained.

In the following drawings the numbers indicate the entities described below:

1 ) mechanical transmission body

2) brake chamber cap 3) traction motor

4) external radiator/container

5) connecting piping of the external recirculation hydraulic circuit

6) reducer internal chamber

7) brake internal chamber 8) upper connecting channel (immission) between the chambers

9) lower connecting channel (drain) between the chambers

AM) transmission system driving shaft (1 )

GR) gear-reducing device

D) Brake disc system integrated in axis with the driving axle (AM).

Claims

1. Electromotive transmission with multifunction integrated braking device for vehicles, of the type in which the transmission substantially consists in a ratio-motor group with integrated brake, comprising: traction motor (3) and integrated transmission with brake (1 ), in an oil bath, characterised in that it substantially includes two chambers (6.7),

- a first chamber (6) where the gear reducing device transmission system (GR) is found and

- a second chamber (7) where the respective braking system (D) is found, said chambers being equipped with lockable intercommunication passage means (8.9) for preventing the possible passage of the oil from one chamber to the other.

2. Electromotive transmission with integrated braking device according to claim 1 , characterised in that said lockable intercommunication passage means (8.9) provide a closing system to prevent as an alternative said intercommunication (8.9).

3. Electromotive transmission with integrated braking device according to any of the previous claims, characterised in that said intercommunication passage means provide at least two channels:

- an upper passage (8) for the flow of the oil from the gear drive chamber (6) to the brake chamber (7);

- a lower passage (9) for the return flow of the oil from the brake chamber (7) to the gear-reducing device chamber (6).

4. Electromotive transmission with integrated braking device according to any of the previous claims, characterised in that said chambers (6.7) and said intercommunication (8.9) are conceived for providing two different oil levels in working (A-Level 1 , B-Level 2).

5. Electromotive transmission with integrated braking device according to the previous claim, characterised in that the oil level working in said gear drive chamber (6) is lower (A-Level 1 ), than the oil level present in working in said brake device (7, B-Level 2).

6. Electromotive transmission with integrated braking device according to any of the previous claims, characterised in that closure means of said intercommunication are provided (8.9).

7. Electromotive transmission with integrated braking device according to any of the previous claims, characterised in that two transmission-brake systems (1 ) opposite said traction motor (3) are provided.

8. Electromotive transmission with integrated braking device according to any of the previous claims, characterised in that said transmission system and brake (1 ) includes a cap (2) to close and access said brake chamber (7-D).

9. Electromotive transmission with integrated braking device according to any of the previous claims, characterised in that external plugs of oil take and delivery for external ducts (5) are provided in said brake chamber (7) to intercommunicate two brake chambers (8) of two transmission devices (1 ), with the intermediation of an external container (4).

10. Electromotive transmission with integrated braking device according to the previous claim, characterised in that said external container (4) is finned for cooling.

11. Electromotive transmission with integrated braking device according to any of the previous claims, characterised in that said brake (D) with respective chamber (7) is placed coaxially to said transmission (1-AM) toward the motor side (3), namely at the opposite side to the wheel connection (C).

12. Electromotive transmission with integrated braking device according to any of the previous claims, characterised in that said traction motor (3) is of the electric type.

13. Electromotive transmission with integrated braking device according to any of the previous claims from 1 to 11 , characterised in that said traction motor (3) is of the hydraulic type.

14. Vehicle provided with a transmission system with integrated brake (1- 3) according to any of the previous claims.