WO2006016196A2

WO2006016196A2 - Clutch device for power transmission system using brake and operating by the differential principle

Info

Publication number: WO2006016196A2
Application number: PCT/HU2005/000087
Authority: WO
Inventors: Attila Vesztroci
Original assignee: Attila Vesztroci
Priority date: 2004-08-09
Filing date: 2005-08-09
Publication date: 2006-02-16
Also published as: HUP0401559A2; HU0401559D0; WO2006016196A3

Abstract

A clutch device for power transmission in vehicles or machines, which comprises a differential gear (2) with sun wheel (3) and planetary bevel gears, and having one drive (i) shaft and two driven semi-shafts (4,5), and a brake (6) mounted on one of the semi-shafts (5), and the other semi-shaft (4) serving as means of power transmission. Based on the operating principles of the differential gear, if the drive shaft (1) is driven by a power-source, with the brake (6) in the released state, the pertinent semi-shaft (5) can rotate freely, thus there cannot be transmission of power through the other semi-shaft (4); in the opposite case however, with the gradual application of the brake (6) the pertinent semi-shaft (5) is gradually stopped, which compels an equivalent increase in the rotation of the other semi-shaft (4), resulting in the gradual transmission of power through the other semi-shaft (4).

Description

Clutch device for power transmission system using brake and operating by the differential principle

The present invention comprises a mechanical clutch device, which makes possible gradual coupling action between two shafts, ^"and automatic operation. It can be used in powered machine systems, in which the jolt-less coupling and de-coupling of different machine units is required, primarily in powered vehicles (cars, truck, trains, etc.).

In a substantial part of the presently used powered vehicles, and in many other types of machine applications, the well-known disc-type mechanical dutch is used, having two discs, one equipped with friction pad and moveable, and having pusher springs and pedal (or lever) control, for the purpose of coupling and de-coupling two shafts in different states of rotation in a gradual manner to avoid stall, for the purpose of transmitting engine power from one shaft to the other as required. This is a proven device, its biggest disadvantages being its susceptibility to undue wear and burning up under heavy load, and that its automated control in practice is not solved. Its automated version in powered vehicles is represented by the hydraulic transmissions, such as the one described in the no. US6758786. patent. They make possible high comfort in driving, and precisely automated control, but they are expensive, therefore they are used almost exclusively in more expensive passenger cars. Because of their lower power transmission efficiency arising from the so-called "slip" in their operation, they are unsuitable for use in heavier cargo carrying road-vehicles.

The purpose of the present invention is to result a mechanical clutch to substitute the aboye mentioned mechanical clutches, whose efficiency in clutching is the same, while not being substantially more complicated or expensive, which makes possible the exclusion of friction components (in the hydraulic brake version, as described later), and makes possible automatic operation in practice. Its further benefits are, that in all versions it is much more durable, and that in the hydraulic brake version it makes possible the design of the gearshift (if used with such) much more flexible, or possibly it may even permit the full exclusion of gearshift. The possible biggest benefit of the present invention is however, that while being a mechanically working device and having the same effectiveness in clutching, it can represent a solution for automated clutch for applications where it was not possible or practical before, primarily in heavy cargo road-vehicles. Of course, the device may be used in a conventional way also as a mechanical clutch with pedal or lever control (for example in farm tractors, heavy duty machines, etc.), in which case it represents a more heavy duty solution for clutch.

Explanation of the drawings:

Fig.1. shows the invention in a cutaway view, the position of the brake being represented by a square.

Fig.2. shows the hydraulic brake, the most preferred type for the invention.

The power from the engine originates through shaft 1 and is placed on sun wheel 3 of differential gear 2 by a bevel gear. For better space utilization the shown parallel arrangement of the shafts may be preferable. Semi-shaft 4 transmits the engine power outside; brake 6 is fastened on semi-shaft 5.

In the unpowered (stationary) state brake 6 is disengaged, thus semi-shaft 5 can rotate freely, which, based on the working order of the differential gear, permits shaft 1 and semi- shaft 4 to rotate freely, independently from each other (idle). When the transmission of engine power is required, the gradual application of brake 6 shall slow up semi-shaft 5, which compels semi-shaft 4 to start revolving at the same rate. The full blocking of brake 6 shall place the full r.p.m. and power coming from the engine on semi-shaft 4 If the transmission of engine power must be stopped, brake 6 must be released, which shall result an idle state. Detailed description

The present invention comprises a mechanical coupling device for machine applications to couple and de-couple two shafts in differing states of rotation in a gradual manner to avoid stall, and to offer the possibility of automatic operation in practice, which utilizes for the task the working principles of the already known differential gear, as invented in 1827 by Onesiphore Pequeur (France), having a plurality of bevel gears forming an epicyclic train of gears, and one in-going powered driveshaft, and two outgoing semi-shafts, and according to whose working principle the mathematical sum total of the two semi-shafts pertaining to each drive shaft revolution value is constant From this it originates, that in the driven state the reduction or increase of the r.p.m. (rotation-per-minute) in one semi-shaft is accompanied be the same increase or reduction of the r.p.m. in the other semi-shaft. The working principle of this differential gear also includes, that in the driven state one semi-shaft can transmit torque only if there is at least an equal braking force on the other semi-shaft; if there is no braking force on one (or both) of the semi-shafts, an idle state will result.

The present invention comprises such a (or an equivalent working order) differential gear. The shaft coming from an outside power source (engine) makes up the in-going shaft of the differential gear ^or is connected with it). However, only one of the semi-shafts is used to transmit engine power, which in case of vehicles leads to the gearshift and / or the wheels, in other applications to the to-be-powered machine unit, and the other semi-shaft is provided with a braking device having a control function. The essence of the invention is, that according to the above-mentioned working principles of the differential gear, in the driven state, the application of the brake with sufficient force shall reduce the r.p.m. of the same side semi-shaft, which shall compel the same increase in the r.p.m. of the other semi-shaft used to transmit engine power; oppositely, the releasing of the brake shall make impossible the transmission of any power, and results an idle state. The full blocking of the brake shall place the full r.p.m. and power coming from the engine on the other semi-shaft. Accordingly, the blocked state of the brake is equivalent to the engaged state of the presently used mechanical clutches, and the released state of the brake is the same as the disengaged state of such clutches. The gradual, load-sensitive application of the braking force ensures the jolt-less coupling action in order to avoid stall.

The brake used in connection with the invention may be any kind of braking device used in machines, such as different types of mechanical brakes, or other, with the same effect, but the most suitable solution appears to be a hydraulic brake of the toothed wheel type excluding any friction components, and the invention subsequently is being explained in association with such brake. The closing valve of this brake is connected with the control mechanism; the closure of the valve shall result braking force, the opening shall stop the braking force. If mechanical brake is used, which works through friction pad or surface, it can be immersed in a suitable liquid (special oil), since it has a separate, closed housing. This oil cools it during braking, and prevents the burning up of the friction surfaces, for this reason the invention results a much more durable clutch in this friction brake form too, than the presently known mechanical clutches.

The automatic (that is without clutch pedal or lever) control may be achieved, if there is an r.p.m. sensor in the engine (centrifugal, electronic), which controls the closing valve of the hydraulic brake, and through it the braking force. At the increase of the engine r.p.m the sensor gradually closes the valve at the rate of the engine r.p.m. increase, therefore applying braking force, until the fully blocked state, to result the transmission of power; oppositely, at the drop of the engine r.p.m. to a preset value (idle r.p.m.) the sensor opens the valve and stops the transmission of power to result idle state, thereby executing the clutching. This ensures load-sensitive start, since the valve of the brake shall be closed (and thus the transmitted power and r.p.m. increased) in a gradual manner, only if, and at the rate at the engine r.p.m. can increase, and if the engine r.p.m. drops back due to too heavy load, the power shall be de-coupled, as described above, therefore the device allows the engine to "labor" under load in order to achieve a successful start.

As for the possibility of automatic operation, in case the invention is used in vehicles in association with conventional gearshift, in order to execute clutching during the shifting of gears, some kind of a sensor is required (mechanical rods, or electric device), connected to the gearshift lever. This sensor senses the movement of the gearshift lever at the start and end positions, and opens, and after the shifting of gear it closes the valve in the brake, as means of clutching. The invention in this form yields semi-automatic operation. Fully automatic operation may be achieved, if the gearshift is equipped with an actuator (such as hydraulic), which executes the shifting of the gears. Sensor must be provided monitoring engine r.p.m. and vehicle speed. Based on input from these two sensors a simple device (such as a chip) controlling the brake valve and the gearshift actuator executes the clutching and the shifting of gears automatically at the preset values.

The invention in the hydraulic brake equipped form makes possible much more flexible gearshift design with less number of gears. The reason is, that in case of conventional mechanical clutches if start from higher gear would be attempted, by the time the vehicle could get moving successfully, the friction pad would burn up. This cannot happen with the invention in this form due to the lack of friction parts. Bigger increments between the gears is also possible for the same reason. It may also be possible, that the special design and closure process of the valve orifice in the brake, possibly also the use of a number of valves each simulating one gear and working in concord, the gearshift might be fully omitted from a vehicle.

The further potential benefits of the invention primarily for powered vehicles are, that it has an r.p.m. reduction immediately after the engine, therefore all revolving .parts of the drive- train run at reduced r.p.m. thereby lowering friction, wear, and fuel consumption; for the same reason there is no need for r.p.m. reduction in the actual differential gear, whose size in the belly of the vehicle may subsequently be smaller; and also that it makes programmed control of torque-management very simple for optimum performance and fuel consumption. In this case the input from the engine r.p.m. sensor and vehicle speed sensor may be fed in a PC (programmable controller) controlling the operation of brake valve and the gearshift actuator, and connected with a selection switch in the dashboard. The selection of the appropriate setting with the switch based on operational conditions (weight carried, city or highway drive, gradient, rain or snow, etc.) the PC executes the clutching and shifting at the most suitable engine r.p.m. and vehicle speed in order to achieve optimum performance. The sun wheel of the differential gear in the invention may also serve as the flywheel of the engine, and contact point for the starter.

Claims

Claims:

1. Coupling device for power transmission in machines, comprising an already known differential gear (2) having a plurality of bevel gears forming an epicyclic train of gears, and one in-going drive shaft (1) and two outgoing semi-shafts (4,5), and a braking device (6) fastened to one of the outgoing semi-shafts (5).

2. The differential gear (2) of Claim 1 , characterized in that arising from its working order, the mathematical sum total of the revolution of the outgoing semi-shafts (4,5) pertaining to each drive shaft (1) revolution value is always constant.

3. The braking device (6) of Claim 1, possessing the possibility of its operation being controlled by an outside controller.